fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include <linux/raid/pq.h>
  29 #include <linux/semaphore.h>
  30 #include <asm/div64.h>
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43 #include "sysfs.h"
  44
  45 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
  46         [BTRFS_RAID_RAID10] = {
  47                 .sub_stripes    = 2,
  48                 .dev_stripes    = 1,
  49                 .devs_max       = 0,    /* 0 == as many as possible */
  50                 .devs_min       = 4,
  51                 .tolerated_failures = 1,
  52                 .devs_increment = 2,
  53                 .ncopies        = 2,
  54         },
  55         [BTRFS_RAID_RAID1] = {
  56                 .sub_stripes    = 1,
  57                 .dev_stripes    = 1,
  58                 .devs_max       = 2,
  59                 .devs_min       = 2,
  60                 .tolerated_failures = 1,
  61                 .devs_increment = 2,
  62                 .ncopies        = 2,
  63         },
  64         [BTRFS_RAID_DUP] = {
  65                 .sub_stripes    = 1,
  66                 .dev_stripes    = 2,
  67                 .devs_max       = 1,
  68                 .devs_min       = 1,
  69                 .tolerated_failures = 0,
  70                 .devs_increment = 1,
  71                 .ncopies        = 2,
  72         },
  73         [BTRFS_RAID_RAID0] = {
  74                 .sub_stripes    = 1,
  75                 .dev_stripes    = 1,
  76                 .devs_max       = 0,
  77                 .devs_min       = 2,
  78                 .tolerated_failures = 0,
  79                 .devs_increment = 1,
  80                 .ncopies        = 1,
  81         },
  82         [BTRFS_RAID_SINGLE] = {
  83                 .sub_stripes    = 1,
  84                 .dev_stripes    = 1,
  85                 .devs_max       = 1,
  86                 .devs_min       = 1,
  87                 .tolerated_failures = 0,
  88                 .devs_increment = 1,
  89                 .ncopies        = 1,
  90         },
  91         [BTRFS_RAID_RAID5] = {
  92                 .sub_stripes    = 1,
  93                 .dev_stripes    = 1,
  94                 .devs_max       = 0,
  95                 .devs_min       = 2,
  96                 .tolerated_failures = 1,
  97                 .devs_increment = 1,
  98                 .ncopies        = 2,
  99         },
 100         [BTRFS_RAID_RAID6] = {
 101                 .sub_stripes    = 1,
 102                 .dev_stripes    = 1,
 103                 .devs_max       = 0,
 104                 .devs_min       = 3,
 105                 .tolerated_failures = 2,
 106                 .devs_increment = 1,
 107                 .ncopies        = 3,
 108         },
 109 };
 110
 111 const u64 btrfs_raid_group[BTRFS_NR_RAID_TYPES] = {
 112         [BTRFS_RAID_RAID10] = BTRFS_BLOCK_GROUP_RAID10,
 113         [BTRFS_RAID_RAID1]  = BTRFS_BLOCK_GROUP_RAID1,
 114         [BTRFS_RAID_DUP]    = BTRFS_BLOCK_GROUP_DUP,
 115         [BTRFS_RAID_RAID0]  = BTRFS_BLOCK_GROUP_RAID0,
 116         [BTRFS_RAID_SINGLE] = 0,
 117         [BTRFS_RAID_RAID5]  = BTRFS_BLOCK_GROUP_RAID5,
 118         [BTRFS_RAID_RAID6]  = BTRFS_BLOCK_GROUP_RAID6,
 119 };
 120
 121 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 122                                 struct btrfs_root *root,
 123                                 struct btrfs_device *device);
 124 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
 125 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 126 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 127 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
 128 static void btrfs_close_one_device(struct btrfs_device *device);
 129
 130 DEFINE_MUTEX(uuid_mutex);
 131 static LIST_HEAD(fs_uuids);
 132 struct list_head *btrfs_get_fs_uuids(void)
 133 {
 134         return &fs_uuids;
 135 }
 136
 137 static struct btrfs_fs_devices *__alloc_fs_devices(void)
 138 {
 139         struct btrfs_fs_devices *fs_devs;
 140
 141         fs_devs = kzalloc(sizeof(*fs_devs), GFP_KERNEL);
 142         if (!fs_devs)
 143                 return ERR_PTR(-ENOMEM);
 144
 145         mutex_init(&fs_devs->device_list_mutex);
 146
 147         INIT_LIST_HEAD(&fs_devs->devices);
 148         INIT_LIST_HEAD(&fs_devs->resized_devices);
 149         INIT_LIST_HEAD(&fs_devs->alloc_list);
 150         INIT_LIST_HEAD(&fs_devs->list);
 151
 152         return fs_devs;
 153 }
 154
 155 /**
 156  * alloc_fs_devices - allocate struct btrfs_fs_devices
 157  * @fsid:       a pointer to UUID for this FS.  If NULL a new UUID is
 158  *              generated.
 159  *
 160  * Return: a pointer to a new &struct btrfs_fs_devices on success;
 161  * ERR_PTR() on error.  Returned struct is not linked onto any lists and
 162  * can be destroyed with kfree() right away.
 163  */
 164 static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
 165 {
 166         struct btrfs_fs_devices *fs_devs;
 167
 168         fs_devs = __alloc_fs_devices();
 169         if (IS_ERR(fs_devs))
 170                 return fs_devs;
 171
 172         if (fsid)
 173                 memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);
 174         else
 175                 generate_random_uuid(fs_devs->fsid);
 176
 177         return fs_devs;
 178 }
 179
 180 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
 181 {
 182         struct btrfs_device *device;
 183         WARN_ON(fs_devices->opened);
 184         while (!list_empty(&fs_devices->devices)) {
 185                 device = list_entry(fs_devices->devices.next,
 186                                     struct btrfs_device, dev_list);
 187                 list_del(&device->dev_list);
 188                 rcu_string_free(device->name);
 189                 kfree(device);
 190         }
 191         kfree(fs_devices);
 192 }
 193
 194 static void btrfs_kobject_uevent(struct block_device *bdev,
 195                                  enum kobject_action action)
 196 {
 197         int ret;
 198
 199         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
 200         if (ret)
 201                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
 202                         action,
 203                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
 204                         &disk_to_dev(bdev->bd_disk)->kobj);
 205 }
 206
 207 void btrfs_cleanup_fs_uuids(void)
 208 {
 209         struct btrfs_fs_devices *fs_devices;
 210
 211         while (!list_empty(&fs_uuids)) {
 212                 fs_devices = list_entry(fs_uuids.next,
 213                                         struct btrfs_fs_devices, list);
 214                 list_del(&fs_devices->list);
 215                 free_fs_devices(fs_devices);
 216         }
 217 }
 218
 219 static struct btrfs_device *__alloc_device(void)
 220 {
 221         struct btrfs_device *dev;
 222
 223         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 224         if (!dev)
 225                 return ERR_PTR(-ENOMEM);
 226
 227         INIT_LIST_HEAD(&dev->dev_list);
 228         INIT_LIST_HEAD(&dev->dev_alloc_list);
 229         INIT_LIST_HEAD(&dev->resized_list);
 230
 231         spin_lock_init(&dev->io_lock);
 232
 233         spin_lock_init(&dev->reada_lock);
 234         atomic_set(&dev->reada_in_flight, 0);
 235         atomic_set(&dev->dev_stats_ccnt, 0);
 236         btrfs_device_data_ordered_init(dev);
 237         INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 238         INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 239
 240         return dev;
 241 }
 242
 243 static noinline struct btrfs_device *__find_device(struct list_head *head,
 244                                                    u64 devid, u8 *uuid)
 245 {
 246         struct btrfs_device *dev;
 247
 248         list_for_each_entry(dev, head, dev_list) {
 249                 if (dev->devid == devid &&
 250                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 251                         return dev;
 252                 }
 253         }
 254         return NULL;
 255 }
 256
 257 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 258 {
 259         struct btrfs_fs_devices *fs_devices;
 260
 261         list_for_each_entry(fs_devices, &fs_uuids, list) {
 262                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 263                         return fs_devices;
 264         }
 265         return NULL;
 266 }
 267
 268 static int
 269 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 270                       int flush, struct block_device **bdev,
 271                       struct buffer_head **bh)
 272 {
 273         int ret;
 274
 275         *bdev = blkdev_get_by_path(device_path, flags, holder);
 276
 277         if (IS_ERR(*bdev)) {
 278                 ret = PTR_ERR(*bdev);
 279                 goto error;
 280         }
 281
 282         if (flush)
 283                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 284         ret = set_blocksize(*bdev, 4096);
 285         if (ret) {
 286                 blkdev_put(*bdev, flags);
 287                 goto error;
 288         }
 289         invalidate_bdev(*bdev);
 290         *bh = btrfs_read_dev_super(*bdev);
 291         if (IS_ERR(*bh)) {
 292                 ret = PTR_ERR(*bh);
 293                 blkdev_put(*bdev, flags);
 294                 goto error;
 295         }
 296
 297         return 0;
 298
 299 error:
 300         *bdev = NULL;
 301         *bh = NULL;
 302         return ret;
 303 }
 304
 305 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 306                         struct bio *head, struct bio *tail)
 307 {
 308
 309         struct bio *old_head;
 310
 311         old_head = pending_bios->head;
 312         pending_bios->head = head;
 313         if (pending_bios->tail)
 314                 tail->bi_next = old_head;
 315         else
 316                 pending_bios->tail = tail;
 317 }
 318
 319 /*
 320  * we try to collect pending bios for a device so we don't get a large
 321  * number of procs sending bios down to the same device.  This greatly
 322  * improves the schedulers ability to collect and merge the bios.
 323  *
 324  * But, it also turns into a long list of bios to process and that is sure
 325  * to eventually make the worker thread block.  The solution here is to
 326  * make some progress and then put this work struct back at the end of
 327  * the list if the block device is congested.  This way, multiple devices
 328  * can make progress from a single worker thread.
 329  */
 330 static noinline void run_scheduled_bios(struct btrfs_device *device)
 331 {
 332         struct bio *pending;
 333         struct backing_dev_info *bdi;
 334         struct btrfs_fs_info *fs_info;
 335         struct btrfs_pending_bios *pending_bios;
 336         struct bio *tail;
 337         struct bio *cur;
 338         int again = 0;
 339         unsigned long num_run;
 340         unsigned long batch_run = 0;
 341         unsigned long limit;
 342         unsigned long last_waited = 0;
 343         int force_reg = 0;
 344         int sync_pending = 0;
 345         struct blk_plug plug;
 346
 347         /*
 348          * this function runs all the bios we've collected for
 349          * a particular device.  We don't want to wander off to
 350          * another device without first sending all of these down.
 351          * So, setup a plug here and finish it off before we return
 352          */
 353         blk_start_plug(&plug);
 354
 355         bdi = blk_get_backing_dev_info(device->bdev);
 356         fs_info = device->dev_root->fs_info;
 357         limit = btrfs_async_submit_limit(fs_info);
 358         limit = limit * 2 / 3;
 359
 360 loop:
 361         spin_lock(&device->io_lock);
 362
 363 loop_lock:
 364         num_run = 0;
 365
 366         /* take all the bios off the list at once and process them
 367          * later on (without the lock held).  But, remember the
 368          * tail and other pointers so the bios can be properly reinserted
 369          * into the list if we hit congestion
 370          */
 371         if (!force_reg && device->pending_sync_bios.head) {
 372                 pending_bios = &device->pending_sync_bios;
 373                 force_reg = 1;
 374         } else {
 375                 pending_bios = &device->pending_bios;
 376                 force_reg = 0;
 377         }
 378
 379         pending = pending_bios->head;
 380         tail = pending_bios->tail;
 381         WARN_ON(pending && !tail);
 382
 383         /*
 384          * if pending was null this time around, no bios need processing
 385          * at all and we can stop.  Otherwise it'll loop back up again
 386          * and do an additional check so no bios are missed.
 387          *
 388          * device->running_pending is used to synchronize with the
 389          * schedule_bio code.
 390          */
 391         if (device->pending_sync_bios.head == NULL &&
 392             device->pending_bios.head == NULL) {
 393                 again = 0;
 394                 device->running_pending = 0;
 395         } else {
 396                 again = 1;
 397                 device->running_pending = 1;
 398         }
 399
 400         pending_bios->head = NULL;
 401         pending_bios->tail = NULL;
 402
 403         spin_unlock(&device->io_lock);
 404
 405         while (pending) {
 406
 407                 rmb();
 408                 /* we want to work on both lists, but do more bios on the
 409                  * sync list than the regular list
 410                  */
 411                 if ((num_run > 32 &&
 412                     pending_bios != &device->pending_sync_bios &&
 413                     device->pending_sync_bios.head) ||
 414                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 415                     device->pending_bios.head)) {
 416                         spin_lock(&device->io_lock);
 417                         requeue_list(pending_bios, pending, tail);
 418                         goto loop_lock;
 419                 }
 420
 421                 cur = pending;
 422                 pending = pending->bi_next;
 423                 cur->bi_next = NULL;
 424
 425                 /*
 426                  * atomic_dec_return implies a barrier for waitqueue_active
 427                  */
 428                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 429                     waitqueue_active(&fs_info->async_submit_wait))
 430                         wake_up(&fs_info->async_submit_wait);
 431
 432                 BUG_ON(atomic_read(&cur->__bi_cnt) == 0);
 433
 434                 /*
 435                  * if we're doing the sync list, record that our
 436                  * plug has some sync requests on it
 437                  *
 438                  * If we're doing the regular list and there are
 439                  * sync requests sitting around, unplug before
 440                  * we add more
 441                  */
 442                 if (pending_bios == &device->pending_sync_bios) {
 443                         sync_pending = 1;
 444                 } else if (sync_pending) {
 445                         blk_finish_plug(&plug);
 446                         blk_start_plug(&plug);
 447                         sync_pending = 0;
 448                 }
 449
 450                 btrfsic_submit_bio(cur->bi_rw, cur);
 451                 num_run++;
 452                 batch_run++;
 453
 454                 cond_resched();
 455
 456                 /*
 457                  * we made progress, there is more work to do and the bdi
 458                  * is now congested.  Back off and let other work structs
 459                  * run instead
 460                  */
 461                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 462                     fs_info->fs_devices->open_devices > 1) {
 463                         struct io_context *ioc;
 464
 465                         ioc = current->io_context;
 466
 467                         /*
 468                          * the main goal here is that we don't want to
 469                          * block if we're going to be able to submit
 470                          * more requests without blocking.
 471                          *
 472                          * This code does two great things, it pokes into
 473                          * the elevator code from a filesystem _and_
 474                          * it makes assumptions about how batching works.
 475                          */
 476                         if (ioc && ioc->nr_batch_requests > 0 &&
 477                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 478                             (last_waited == 0 ||
 479                              ioc->last_waited == last_waited)) {
 480                                 /*
 481                                  * we want to go through our batch of
 482                                  * requests and stop.  So, we copy out
 483                                  * the ioc->last_waited time and test
 484                                  * against it before looping
 485                                  */
 486                                 last_waited = ioc->last_waited;
 487                                 cond_resched();
 488                                 continue;
 489                         }
 490                         spin_lock(&device->io_lock);
 491                         requeue_list(pending_bios, pending, tail);
 492                         device->running_pending = 1;
 493
 494                         spin_unlock(&device->io_lock);
 495                         btrfs_queue_work(fs_info->submit_workers,
 496                                          &device->work);
 497                         goto done;
 498                 }
 499                 /* unplug every 64 requests just for good measure */
 500                 if (batch_run % 64 == 0) {
 501                         blk_finish_plug(&plug);
 502                         blk_start_plug(&plug);
 503                         sync_pending = 0;
 504                 }
 505         }
 506
 507         cond_resched();
 508         if (again)
 509                 goto loop;
 510
 511         spin_lock(&device->io_lock);
 512         if (device->pending_bios.head || device->pending_sync_bios.head)
 513                 goto loop_lock;
 514         spin_unlock(&device->io_lock);
 515
 516 done:
 517         blk_finish_plug(&plug);
 518 }
 519
 520 static void pending_bios_fn(struct btrfs_work *work)
 521 {
 522         struct btrfs_device *device;
 523
 524         device = container_of(work, struct btrfs_device, work);
 525         run_scheduled_bios(device);
 526 }
 527
 528
 529 void btrfs_free_stale_device(struct btrfs_device *cur_dev)
 530 {
 531         struct btrfs_fs_devices *fs_devs;
 532         struct btrfs_device *dev;
 533
 534         if (!cur_dev->name)
 535                 return;
 536
 537         list_for_each_entry(fs_devs, &fs_uuids, list) {
 538                 int del = 1;
 539
 540                 if (fs_devs->opened)
 541                         continue;
 542                 if (fs_devs->seeding)
 543                         continue;
 544
 545                 list_for_each_entry(dev, &fs_devs->devices, dev_list) {
 546
 547                         if (dev == cur_dev)
 548                                 continue;
 549                         if (!dev->name)
 550                                 continue;
 551
 552                         /*
 553                          * Todo: This won't be enough. What if the same device
 554                          * comes back (with new uuid and) with its mapper path?
 555                          * But for now, this does help as mostly an admin will
 556                          * either use mapper or non mapper path throughout.
 557                          */
 558                         rcu_read_lock();
 559                         del = strcmp(rcu_str_deref(dev->name),
 560                                                 rcu_str_deref(cur_dev->name));
 561                         rcu_read_unlock();
 562                         if (!del)
 563                                 break;
 564                 }
 565
 566                 if (!del) {
 567                         /* delete the stale device */
 568                         if (fs_devs->num_devices == 1) {
 569                                 btrfs_sysfs_remove_fsid(fs_devs);
 570                                 list_del(&fs_devs->list);
 571                                 free_fs_devices(fs_devs);
 572                         } else {
 573                                 fs_devs->num_devices--;
 574                                 list_del(&dev->dev_list);
 575                                 rcu_string_free(dev->name);
 576                                 kfree(dev);
 577                         }
 578                         break;
 579                 }
 580         }
 581 }
 582
 583 /*
 584  * Add new device to list of registered devices
 585  *
 586  * Returns:
 587  * 1   - first time device is seen
 588  * 0   - device already known
 589  * < 0 - error
 590  */
 591 static noinline int device_list_add(const char *path,
 592                            struct btrfs_super_block *disk_super,
 593                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 594 {
 595         struct btrfs_device *device;
 596         struct btrfs_fs_devices *fs_devices;
 597         struct rcu_string *name;
 598         int ret = 0;
 599         u64 found_transid = btrfs_super_generation(disk_super);
 600
 601         fs_devices = find_fsid(disk_super->fsid);
 602         if (!fs_devices) {
 603                 fs_devices = alloc_fs_devices(disk_super->fsid);
 604                 if (IS_ERR(fs_devices))
 605                         return PTR_ERR(fs_devices);
 606
 607                 list_add(&fs_devices->list, &fs_uuids);
 608
 609                 device = NULL;
 610         } else {
 611                 device = __find_device(&fs_devices->devices, devid,
 612                                        disk_super->dev_item.uuid);
 613         }
 614
 615         if (!device) {
 616                 if (fs_devices->opened)
 617                         return -EBUSY;
 618
 619                 device = btrfs_alloc_device(NULL, &devid,
 620                                             disk_super->dev_item.uuid);
 621                 if (IS_ERR(device)) {
 622                         /* we can safely leave the fs_devices entry around */
 623                         return PTR_ERR(device);
 624                 }
 625
 626                 name = rcu_string_strdup(path, GFP_NOFS);
 627                 if (!name) {
 628                         kfree(device);
 629                         return -ENOMEM;
 630                 }
 631                 rcu_assign_pointer(device->name, name);
 632
 633                 mutex_lock(&fs_devices->device_list_mutex);
 634                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 635                 fs_devices->num_devices++;
 636                 mutex_unlock(&fs_devices->device_list_mutex);
 637
 638                 ret = 1;
 639                 device->fs_devices = fs_devices;
 640         } else if (!device->name || strcmp(device->name->str, path)) {
 641                 /*
 642                  * When FS is already mounted.
 643                  * 1. If you are here and if the device->name is NULL that
 644                  *    means this device was missing at time of FS mount.
 645                  * 2. If you are here and if the device->name is different
 646                  *    from 'path' that means either
 647                  *      a. The same device disappeared and reappeared with
 648                  *         different name. or
 649                  *      b. The missing-disk-which-was-replaced, has
 650                  *         reappeared now.
 651                  *
 652                  * We must allow 1 and 2a above. But 2b would be a spurious
 653                  * and unintentional.
 654                  *
 655                  * Further in case of 1 and 2a above, the disk at 'path'
 656                  * would have missed some transaction when it was away and
 657                  * in case of 2a the stale bdev has to be updated as well.
 658                  * 2b must not be allowed at all time.
 659                  */
 660
 661                 /*
 662                  * For now, we do allow update to btrfs_fs_device through the
 663                  * btrfs dev scan cli after FS has been mounted.  We're still
 664                  * tracking a problem where systems fail mount by subvolume id
 665                  * when we reject replacement on a mounted FS.
 666                  */
 667                 if (!fs_devices->opened && found_transid < device->generation) {
 668                         /*
 669                          * That is if the FS is _not_ mounted and if you
 670                          * are here, that means there is more than one
 671                          * disk with same uuid and devid.We keep the one
 672                          * with larger generation number or the last-in if
 673                          * generation are equal.
 674                          */
 675                         return -EEXIST;
 676                 }
 677
 678                 name = rcu_string_strdup(path, GFP_NOFS);
 679                 if (!name)
 680                         return -ENOMEM;
 681                 rcu_string_free(device->name);
 682                 rcu_assign_pointer(device->name, name);
 683                 if (device->missing) {
 684                         fs_devices->missing_devices--;
 685                         device->missing = 0;
 686                 }
 687         }
 688
 689         /*
 690          * Unmount does not free the btrfs_device struct but would zero
 691          * generation along with most of the other members. So just update
 692          * it back. We need it to pick the disk with largest generation
 693          * (as above).
 694          */
 695         if (!fs_devices->opened)
 696                 device->generation = found_transid;
 697
 698         /*
 699          * if there is new btrfs on an already registered device,
 700          * then remove the stale device entry.
 701          */
 702         btrfs_free_stale_device(device);
 703
 704         *fs_devices_ret = fs_devices;
 705
 706         return ret;
 707 }
 708
 709 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 710 {
 711         struct btrfs_fs_devices *fs_devices;
 712         struct btrfs_device *device;
 713         struct btrfs_device *orig_dev;
 714
 715         fs_devices = alloc_fs_devices(orig->fsid);
 716         if (IS_ERR(fs_devices))
 717                 return fs_devices;
 718
 719         mutex_lock(&orig->device_list_mutex);
 720         fs_devices->total_devices = orig->total_devices;
 721
 722         /* We have held the volume lock, it is safe to get the devices. */
 723         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 724                 struct rcu_string *name;
 725
 726                 device = btrfs_alloc_device(NULL, &orig_dev->devid,
 727                                             orig_dev->uuid);
 728                 if (IS_ERR(device))
 729                         goto error;
 730
 731                 /*
 732                  * This is ok to do without rcu read locked because we hold the
 733                  * uuid mutex so nothing we touch in here is going to disappear.
 734                  */
 735                 if (orig_dev->name) {
 736                         name = rcu_string_strdup(orig_dev->name->str,
 737                                         GFP_KERNEL);
 738                         if (!name) {
 739                                 kfree(device);
 740                                 goto error;
 741                         }
 742                         rcu_assign_pointer(device->name, name);
 743                 }
 744
 745                 list_add(&device->dev_list, &fs_devices->devices);
 746                 device->fs_devices = fs_devices;
 747                 fs_devices->num_devices++;
 748         }
 749         mutex_unlock(&orig->device_list_mutex);
 750         return fs_devices;
 751 error:
 752         mutex_unlock(&orig->device_list_mutex);
 753         free_fs_devices(fs_devices);
 754         return ERR_PTR(-ENOMEM);
 755 }
 756
 757 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step)
 758 {
 759         struct btrfs_device *device, *next;
 760         struct btrfs_device *latest_dev = NULL;
 761
 762         mutex_lock(&uuid_mutex);
 763 again:
 764         /* This is the initialized path, it is safe to release the devices. */
 765         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 766                 if (device->in_fs_metadata) {
 767                         if (!device->is_tgtdev_for_dev_replace &&
 768                             (!latest_dev ||
 769                              device->generation > latest_dev->generation)) {
 770                                 latest_dev = device;
 771                         }
 772                         continue;
 773                 }
 774
 775                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 776                         /*
 777                          * In the first step, keep the device which has
 778                          * the correct fsid and the devid that is used
 779                          * for the dev_replace procedure.
 780                          * In the second step, the dev_replace state is
 781                          * read from the device tree and it is known
 782                          * whether the procedure is really active or
 783                          * not, which means whether this device is
 784                          * used or whether it should be removed.
 785                          */
 786                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 787                                 continue;
 788                         }
 789                 }
 790                 if (device->bdev) {
 791                         blkdev_put(device->bdev, device->mode);
 792                         device->bdev = NULL;
 793                         fs_devices->open_devices--;
 794                 }
 795                 if (device->writeable) {
 796                         list_del_init(&device->dev_alloc_list);
 797                         device->writeable = 0;
 798                         if (!device->is_tgtdev_for_dev_replace)
 799                                 fs_devices->rw_devices--;
 800                 }
 801                 list_del_init(&device->dev_list);
 802                 fs_devices->num_devices--;
 803                 rcu_string_free(device->name);
 804                 kfree(device);
 805         }
 806
 807         if (fs_devices->seed) {
 808                 fs_devices = fs_devices->seed;
 809                 goto again;
 810         }
 811
 812         fs_devices->latest_bdev = latest_dev->bdev;
 813
 814         mutex_unlock(&uuid_mutex);
 815 }
 816
 817 static void __free_device(struct work_struct *work)
 818 {
 819         struct btrfs_device *device;
 820
 821         device = container_of(work, struct btrfs_device, rcu_work);
 822
 823         if (device->bdev)
 824                 blkdev_put(device->bdev, device->mode);
 825
 826         rcu_string_free(device->name);
 827         kfree(device);
 828 }
 829
 830 static void free_device(struct rcu_head *head)
 831 {
 832         struct btrfs_device *device;
 833
 834         device = container_of(head, struct btrfs_device, rcu);
 835
 836         INIT_WORK(&device->rcu_work, __free_device);
 837         schedule_work(&device->rcu_work);
 838 }
 839
 840 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 841 {
 842         struct btrfs_device *device, *tmp;
 843
 844         if (--fs_devices->opened > 0)
 845                 return 0;
 846
 847         mutex_lock(&fs_devices->device_list_mutex);
 848         list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) {
 849                 btrfs_close_one_device(device);
 850         }
 851         mutex_unlock(&fs_devices->device_list_mutex);
 852
 853         WARN_ON(fs_devices->open_devices);
 854         WARN_ON(fs_devices->rw_devices);
 855         fs_devices->opened = 0;
 856         fs_devices->seeding = 0;
 857
 858         return 0;
 859 }
 860
 861 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 862 {
 863         struct btrfs_fs_devices *seed_devices = NULL;
 864         int ret;
 865
 866         mutex_lock(&uuid_mutex);
 867         ret = __btrfs_close_devices(fs_devices);
 868         if (!fs_devices->opened) {
 869                 seed_devices = fs_devices->seed;
 870                 fs_devices->seed = NULL;
 871         }
 872         mutex_unlock(&uuid_mutex);
 873
 874         while (seed_devices) {
 875                 fs_devices = seed_devices;
 876                 seed_devices = fs_devices->seed;
 877                 __btrfs_close_devices(fs_devices);
 878                 free_fs_devices(fs_devices);
 879         }
 880         /*
 881          * Wait for rcu kworkers under __btrfs_close_devices
 882          * to finish all blkdev_puts so device is really
 883          * free when umount is done.
 884          */
 885         rcu_barrier();
 886         return ret;
 887 }
 888
 889 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 890                                 fmode_t flags, void *holder)
 891 {
 892         struct request_queue *q;
 893         struct block_device *bdev;
 894         struct list_head *head = &fs_devices->devices;
 895         struct btrfs_device *device;
 896         struct btrfs_device *latest_dev = NULL;
 897         struct buffer_head *bh;
 898         struct btrfs_super_block *disk_super;
 899         u64 devid;
 900         int seeding = 1;
 901         int ret = 0;
 902
 903         flags |= FMODE_EXCL;
 904
 905         list_for_each_entry(device, head, dev_list) {
 906                 if (device->bdev)
 907                         continue;
 908                 if (!device->name)
 909                         continue;
 910
 911                 /* Just open everything we can; ignore failures here */
 912                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 913                                             &bdev, &bh))
 914                         continue;
 915
 916                 disk_super = (struct btrfs_super_block *)bh->b_data;
 917                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 918                 if (devid != device->devid)
 919                         goto error_brelse;
 920
 921                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 922                            BTRFS_UUID_SIZE))
 923                         goto error_brelse;
 924
 925                 device->generation = btrfs_super_generation(disk_super);
 926                 if (!latest_dev ||
 927                     device->generation > latest_dev->generation)
 928                         latest_dev = device;
 929
 930                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 931                         device->writeable = 0;
 932                 } else {
 933                         device->writeable = !bdev_read_only(bdev);
 934                         seeding = 0;
 935                 }
 936
 937                 q = bdev_get_queue(bdev);
 938                 if (blk_queue_discard(q))
 939                         device->can_discard = 1;
 940
 941                 device->bdev = bdev;
 942                 device->in_fs_metadata = 0;
 943                 device->mode = flags;
 944
 945                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 946                         fs_devices->rotating = 1;
 947
 948                 fs_devices->open_devices++;
 949                 if (device->writeable &&
 950                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
 951                         fs_devices->rw_devices++;
 952                         list_add(&device->dev_alloc_list,
 953                                  &fs_devices->alloc_list);
 954                 }
 955                 brelse(bh);
 956                 continue;
 957
 958 error_brelse:
 959                 brelse(bh);
 960                 blkdev_put(bdev, flags);
 961                 continue;
 962         }
 963         if (fs_devices->open_devices == 0) {
 964                 ret = -EINVAL;
 965                 goto out;
 966         }
 967         fs_devices->seeding = seeding;
 968         fs_devices->opened = 1;
 969         fs_devices->latest_bdev = latest_dev->bdev;
 970         fs_devices->total_rw_bytes = 0;
 971 out:
 972         return ret;
 973 }
 974
 975 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 976                        fmode_t flags, void *holder)
 977 {
 978         int ret;
 979
 980         mutex_lock(&uuid_mutex);
 981         if (fs_devices->opened) {
 982                 fs_devices->opened++;
 983                 ret = 0;
 984         } else {
 985                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 986         }
 987         mutex_unlock(&uuid_mutex);
 988         return ret;
 989 }
 990
 991 /*
 992  * Look for a btrfs signature on a device. This may be called out of the mount path
 993  * and we are not allowed to call set_blocksize during the scan. The superblock
 994  * is read via pagecache
 995  */
 996 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 997                           struct btrfs_fs_devices **fs_devices_ret)
 998 {
 999         struct btrfs_super_block *disk_super;
1000         struct block_device *bdev;
1001         struct page *page;
1002         void *p;
1003         int ret = -EINVAL;
1004         u64 devid;
1005         u64 transid;
1006         u64 total_devices;
1007         u64 bytenr;
1008         pgoff_t index;
1009
1010         /*
1011          * we would like to check all the supers, but that would make
1012          * a btrfs mount succeed after a mkfs from a different FS.
1013          * So, we need to add a special mount option to scan for
1014          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
1015          */
1016         bytenr = btrfs_sb_offset(0);
1017         flags |= FMODE_EXCL;
1018         mutex_lock(&uuid_mutex);
1019
1020         bdev = blkdev_get_by_path(path, flags, holder);
1021
1022         if (IS_ERR(bdev)) {
1023                 ret = PTR_ERR(bdev);
1024                 goto error;
1025         }
1026
1027         /* make sure our super fits in the device */
1028         if (bytenr + PAGE_SIZE >= i_size_read(bdev->bd_inode))
1029                 goto error_bdev_put;
1030
1031         /* make sure our super fits in the page */
1032         if (sizeof(*disk_super) > PAGE_SIZE)
1033                 goto error_bdev_put;
1034
1035         /* make sure our super doesn't straddle pages on disk */
1036         index = bytenr >> PAGE_SHIFT;
1037         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_SHIFT != index)
1038                 goto error_bdev_put;
1039
1040         /* pull in the page with our super */
1041         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
1042                                    index, GFP_NOFS);
1043
1044         if (IS_ERR_OR_NULL(page))
1045                 goto error_bdev_put;
1046
1047         p = kmap(page);
1048
1049         /* align our pointer to the offset of the super block */
1050         disk_super = p + (bytenr & ~PAGE_MASK);
1051
1052         if (btrfs_super_bytenr(disk_super) != bytenr ||
1053             btrfs_super_magic(disk_super) != BTRFS_MAGIC)
1054                 goto error_unmap;
1055
1056         devid = btrfs_stack_device_id(&disk_super->dev_item);
1057         transid = btrfs_super_generation(disk_super);
1058         total_devices = btrfs_super_num_devices(disk_super);
1059
1060         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
1061         if (ret > 0) {
1062                 if (disk_super->label[0]) {
1063                         if (disk_super->label[BTRFS_LABEL_SIZE - 1])
1064                                 disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
1065                         printk(KERN_INFO "BTRFS: device label %s ", disk_super->label);
1066                 } else {
1067                         printk(KERN_INFO "BTRFS: device fsid %pU ", disk_super->fsid);
1068                 }
1069
1070                 printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
1071                 ret = 0;
1072         }
1073         if (!ret && fs_devices_ret)
1074                 (*fs_devices_ret)->total_devices = total_devices;
1075
1076 error_unmap:
1077         kunmap(page);
1078         put_page(page);
1079
1080 error_bdev_put:
1081         blkdev_put(bdev, flags);
1082 error:
1083         mutex_unlock(&uuid_mutex);
1084         return ret;
1085 }
1086
1087 /* helper to account the used device space in the range */
1088 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
1089                                    u64 end, u64 *length)
1090 {
1091         struct btrfs_key key;
1092         struct btrfs_root *root = device->dev_root;
1093         struct btrfs_dev_extent *dev_extent;
1094         struct btrfs_path *path;
1095         u64 extent_end;
1096         int ret;
1097         int slot;
1098         struct extent_buffer *l;
1099
1100         *length = 0;
1101
1102         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
1103                 return 0;
1104
1105         path = btrfs_alloc_path();
1106         if (!path)
1107                 return -ENOMEM;
1108         path->reada = READA_FORWARD;
1109
1110         key.objectid = device->devid;
1111         key.offset = start;
1112         key.type = BTRFS_DEV_EXTENT_KEY;
1113
1114         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1115         if (ret < 0)
1116                 goto out;
1117         if (ret > 0) {
1118                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1119                 if (ret < 0)
1120                         goto out;
1121         }
1122
1123         while (1) {
1124                 l = path->nodes[0];
1125                 slot = path->slots[0];
1126                 if (slot >= btrfs_header_nritems(l)) {
1127                         ret = btrfs_next_leaf(root, path);
1128                         if (ret == 0)
1129                                 continue;
1130                         if (ret < 0)
1131                                 goto out;
1132
1133                         break;
1134                 }
1135                 btrfs_item_key_to_cpu(l, &key, slot);
1136
1137                 if (key.objectid < device->devid)
1138                         goto next;
1139
1140                 if (key.objectid > device->devid)
1141                         break;
1142
1143                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1144                         goto next;
1145
1146                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1147                 extent_end = key.offset + btrfs_dev_extent_length(l,
1148                                                                   dev_extent);
1149                 if (key.offset <= start && extent_end > end) {
1150                         *length = end - start + 1;
1151                         break;
1152                 } else if (key.offset <= start && extent_end > start)
1153                         *length += extent_end - start;
1154                 else if (key.offset > start && extent_end <= end)
1155                         *length += extent_end - key.offset;
1156                 else if (key.offset > start && key.offset <= end) {
1157                         *length += end - key.offset + 1;
1158                         break;
1159                 } else if (key.offset > end)
1160                         break;
1161
1162 next:
1163                 path->slots[0]++;
1164         }
1165         ret = 0;
1166 out:
1167         btrfs_free_path(path);
1168         return ret;
1169 }
1170
1171 static int contains_pending_extent(struct btrfs_transaction *transaction,
1172                                    struct btrfs_device *device,
1173                                    u64 *start, u64 len)
1174 {
1175         struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
1176         struct extent_map *em;
1177         struct list_head *search_list = &fs_info->pinned_chunks;
1178         int ret = 0;
1179         u64 physical_start = *start;
1180
1181         if (transaction)
1182                 search_list = &transaction->pending_chunks;
1183 again:
1184         list_for_each_entry(em, search_list, list) {
1185                 struct map_lookup *map;
1186                 int i;
1187
1188                 map = em->map_lookup;
1189                 for (i = 0; i < map->num_stripes; i++) {
1190                         u64 end;
1191
1192                         if (map->stripes[i].dev != device)
1193                                 continue;
1194                         if (map->stripes[i].physical >= physical_start + len ||
1195                             map->stripes[i].physical + em->orig_block_len <=
1196                             physical_start)
1197                                 continue;
1198                         /*
1199                          * Make sure that while processing the pinned list we do
1200                          * not override our *start with a lower value, because
1201                          * we can have pinned chunks that fall within this
1202                          * device hole and that have lower physical addresses
1203                          * than the pending chunks we processed before. If we
1204                          * do not take this special care we can end up getting
1205                          * 2 pending chunks that start at the same physical
1206                          * device offsets because the end offset of a pinned
1207                          * chunk can be equal to the start offset of some
1208                          * pending chunk.
1209                          */
1210                         end = map->stripes[i].physical + em->orig_block_len;
1211                         if (end > *start) {
1212                                 *start = end;
1213                                 ret = 1;
1214                         }
1215                 }
1216         }
1217         if (search_list != &fs_info->pinned_chunks) {
1218                 search_list = &fs_info->pinned_chunks;
1219                 goto again;
1220         }
1221
1222         return ret;
1223 }
1224
1225
1226 /*
1227  * find_free_dev_extent_start - find free space in the specified device
1228  * @device:       the device which we search the free space in
1229  * @num_bytes:    the size of the free space that we need
1230  * @search_start: the position from which to begin the search
1231  * @start:        store the start of the free space.
1232  * @len:          the size of the free space. that we find, or the size
1233  *                of the max free space if we don't find suitable free space
1234  *
1235  * this uses a pretty simple search, the expectation is that it is
1236  * called very infrequently and that a given device has a small number
1237  * of extents
1238  *
1239  * @start is used to store the start of the free space if we find. But if we
1240  * don't find suitable free space, it will be used to store the start position
1241  * of the max free space.
1242  *
1243  * @len is used to store the size of the free space that we find.
1244  * But if we don't find suitable free space, it is used to store the size of
1245  * the max free space.
1246  */
1247 int find_free_dev_extent_start(struct btrfs_transaction *transaction,
1248                                struct btrfs_device *device, u64 num_bytes,
1249                                u64 search_start, u64 *start, u64 *len)
1250 {
1251         struct btrfs_key key;
1252         struct btrfs_root *root = device->dev_root;
1253         struct btrfs_dev_extent *dev_extent;
1254         struct btrfs_path *path;
1255         u64 hole_size;
1256         u64 max_hole_start;
1257         u64 max_hole_size;
1258         u64 extent_end;
1259         u64 search_end = device->total_bytes;
1260         int ret;
1261         int slot;
1262         struct extent_buffer *l;
1263         u64 min_search_start;
1264
1265         /*
1266          * We don't want to overwrite the superblock on the drive nor any area
1267          * used by the boot loader (grub for example), so we make sure to start
1268          * at an offset of at least 1MB.
1269          */
1270         min_search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1271         search_start = max(search_start, min_search_start);
1272
1273         path = btrfs_alloc_path();
1274         if (!path)
1275                 return -ENOMEM;
1276
1277         max_hole_start = search_start;
1278         max_hole_size = 0;
1279
1280 again:
1281         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1282                 ret = -ENOSPC;
1283                 goto out;
1284         }
1285
1286         path->reada = READA_FORWARD;
1287         path->search_commit_root = 1;
1288         path->skip_locking = 1;
1289
1290         key.objectid = device->devid;
1291         key.offset = search_start;
1292         key.type = BTRFS_DEV_EXTENT_KEY;
1293
1294         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1295         if (ret < 0)
1296                 goto out;
1297         if (ret > 0) {
1298                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1299                 if (ret < 0)
1300                         goto out;
1301         }
1302
1303         while (1) {
1304                 l = path->nodes[0];
1305                 slot = path->slots[0];
1306                 if (slot >= btrfs_header_nritems(l)) {
1307                         ret = btrfs_next_leaf(root, path);
1308                         if (ret == 0)
1309                                 continue;
1310                         if (ret < 0)
1311                                 goto out;
1312
1313                         break;
1314                 }
1315                 btrfs_item_key_to_cpu(l, &key, slot);
1316
1317                 if (key.objectid < device->devid)
1318                         goto next;
1319
1320                 if (key.objectid > device->devid)
1321                         break;
1322
1323                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1324                         goto next;
1325
1326                 if (key.offset > search_start) {
1327                         hole_size = key.offset - search_start;
1328
1329                         /*
1330                          * Have to check before we set max_hole_start, otherwise
1331                          * we could end up sending back this offset anyway.
1332                          */
1333                         if (contains_pending_extent(transaction, device,
1334                                                     &search_start,
1335                                                     hole_size)) {
1336                                 if (key.offset >= search_start) {
1337                                         hole_size = key.offset - search_start;
1338                                 } else {
1339                                         WARN_ON_ONCE(1);
1340                                         hole_size = 0;
1341                                 }
1342                         }
1343
1344                         if (hole_size > max_hole_size) {
1345                                 max_hole_start = search_start;
1346                                 max_hole_size = hole_size;
1347                         }
1348
1349                         /*
1350                          * If this free space is greater than which we need,
1351                          * it must be the max free space that we have found
1352                          * until now, so max_hole_start must point to the start
1353                          * of this free space and the length of this free space
1354                          * is stored in max_hole_size. Thus, we return
1355                          * max_hole_start and max_hole_size and go back to the
1356                          * caller.
1357                          */
1358                         if (hole_size >= num_bytes) {
1359                                 ret = 0;
1360                                 goto out;
1361                         }
1362                 }
1363
1364                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1365                 extent_end = key.offset + btrfs_dev_extent_length(l,
1366                                                                   dev_extent);
1367                 if (extent_end > search_start)
1368                         search_start = extent_end;
1369 next:
1370                 path->slots[0]++;
1371                 cond_resched();
1372         }
1373
1374         /*
1375          * At this point, search_start should be the end of
1376          * allocated dev extents, and when shrinking the device,
1377          * search_end may be smaller than search_start.
1378          */
1379         if (search_end > search_start) {
1380                 hole_size = search_end - search_start;
1381
1382                 if (contains_pending_extent(transaction, device, &search_start,
1383                                             hole_size)) {
1384                         btrfs_release_path(path);
1385                         goto again;
1386                 }
1387
1388                 if (hole_size > max_hole_size) {
1389                         max_hole_start = search_start;
1390                         max_hole_size = hole_size;
1391                 }
1392         }
1393
1394         /* See above. */
1395         if (max_hole_size < num_bytes)
1396                 ret = -ENOSPC;
1397         else
1398                 ret = 0;
1399
1400 out:
1401         btrfs_free_path(path);
1402         *start = max_hole_start;
1403         if (len)
1404                 *len = max_hole_size;
1405         return ret;
1406 }
1407
1408 int find_free_dev_extent(struct btrfs_trans_handle *trans,
1409                          struct btrfs_device *device, u64 num_bytes,
1410                          u64 *start, u64 *len)
1411 {
1412         /* FIXME use last free of some kind */
1413         return find_free_dev_extent_start(trans->transaction, device,
1414                                           num_bytes, 0, start, len);
1415 }
1416
1417 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1418                           struct btrfs_device *device,
1419                           u64 start, u64 *dev_extent_len)
1420 {
1421         int ret;
1422         struct btrfs_path *path;
1423         struct btrfs_root *root = device->dev_root;
1424         struct btrfs_key key;
1425         struct btrfs_key found_key;
1426         struct extent_buffer *leaf = NULL;
1427         struct btrfs_dev_extent *extent = NULL;
1428
1429         path = btrfs_alloc_path();
1430         if (!path)
1431                 return -ENOMEM;
1432
1433         key.objectid = device->devid;
1434         key.offset = start;
1435         key.type = BTRFS_DEV_EXTENT_KEY;
1436 again:
1437         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1438         if (ret > 0) {
1439                 ret = btrfs_previous_item(root, path, key.objectid,
1440                                           BTRFS_DEV_EXTENT_KEY);
1441                 if (ret)
1442                         goto out;
1443                 leaf = path->nodes[0];
1444                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1445                 extent = btrfs_item_ptr(leaf, path->slots[0],
1446                                         struct btrfs_dev_extent);
1447                 BUG_ON(found_key.offset > start || found_key.offset +
1448                        btrfs_dev_extent_length(leaf, extent) < start);
1449                 key = found_key;
1450                 btrfs_release_path(path);
1451                 goto again;
1452         } else if (ret == 0) {
1453                 leaf = path->nodes[0];
1454                 extent = btrfs_item_ptr(leaf, path->slots[0],
1455                                         struct btrfs_dev_extent);
1456         } else {
1457                 btrfs_std_error(root->fs_info, ret, "Slot search failed");
1458                 goto out;
1459         }
1460
1461         *dev_extent_len = btrfs_dev_extent_length(leaf, extent);
1462
1463         ret = btrfs_del_item(trans, root, path);
1464         if (ret) {
1465                 btrfs_std_error(root->fs_info, ret,
1466                             "Failed to remove dev extent item");
1467         } else {
1468                 set_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags);
1469         }
1470 out:
1471         btrfs_free_path(path);
1472         return ret;
1473 }
1474
1475 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1476                                   struct btrfs_device *device,
1477                                   u64 chunk_tree, u64 chunk_objectid,
1478                                   u64 chunk_offset, u64 start, u64 num_bytes)
1479 {
1480         int ret;
1481         struct btrfs_path *path;
1482         struct btrfs_root *root = device->dev_root;
1483         struct btrfs_dev_extent *extent;
1484         struct extent_buffer *leaf;
1485         struct btrfs_key key;
1486
1487         WARN_ON(!device->in_fs_metadata);
1488         WARN_ON(device->is_tgtdev_for_dev_replace);
1489         path = btrfs_alloc_path();
1490         if (!path)
1491                 return -ENOMEM;
1492
1493         key.objectid = device->devid;
1494         key.offset = start;
1495         key.type = BTRFS_DEV_EXTENT_KEY;
1496         ret = btrfs_insert_empty_item(trans, root, path, &key,
1497                                       sizeof(*extent));
1498         if (ret)
1499                 goto out;
1500
1501         leaf = path->nodes[0];
1502         extent = btrfs_item_ptr(leaf, path->slots[0],
1503                                 struct btrfs_dev_extent);
1504         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1505         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1506         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1507
1508         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1509                     btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
1510
1511         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1512         btrfs_mark_buffer_dirty(leaf);
1513 out:
1514         btrfs_free_path(path);
1515         return ret;
1516 }
1517
1518 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
1519 {
1520         struct extent_map_tree *em_tree;
1521         struct extent_map *em;
1522         struct rb_node *n;
1523         u64 ret = 0;
1524
1525         em_tree = &fs_info->mapping_tree.map_tree;
1526         read_lock(&em_tree->lock);
1527         n = rb_last(&em_tree->map);
1528         if (n) {
1529                 em = rb_entry(n, struct extent_map, rb_node);
1530                 ret = em->start + em->len;
1531         }
1532         read_unlock(&em_tree->lock);
1533
1534         return ret;
1535 }
1536
1537 static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
1538                                     u64 *devid_ret)
1539 {
1540         int ret;
1541         struct btrfs_key key;
1542         struct btrfs_key found_key;
1543         struct btrfs_path *path;
1544
1545         path = btrfs_alloc_path();
1546         if (!path)
1547                 return -ENOMEM;
1548
1549         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1550         key.type = BTRFS_DEV_ITEM_KEY;
1551         key.offset = (u64)-1;
1552
1553         ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
1554         if (ret < 0)
1555                 goto error;
1556
1557         BUG_ON(ret == 0); /* Corruption */
1558
1559         ret = btrfs_previous_item(fs_info->chunk_root, path,
1560                                   BTRFS_DEV_ITEMS_OBJECTID,
1561                                   BTRFS_DEV_ITEM_KEY);
1562         if (ret) {
1563                 *devid_ret = 1;
1564         } else {
1565                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1566                                       path->slots[0]);
1567                 *devid_ret = found_key.offset + 1;
1568         }
1569         ret = 0;
1570 error:
1571         btrfs_free_path(path);
1572         return ret;
1573 }
1574
1575 /*
1576  * the device information is stored in the chunk root
1577  * the btrfs_device struct should be fully filled in
1578  */
1579 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1580                             struct btrfs_root *root,
1581                             struct btrfs_device *device)
1582 {
1583         int ret;
1584         struct btrfs_path *path;
1585         struct btrfs_dev_item *dev_item;
1586         struct extent_buffer *leaf;
1587         struct btrfs_key key;
1588         unsigned long ptr;
1589
1590         root = root->fs_info->chunk_root;
1591
1592         path = btrfs_alloc_path();
1593         if (!path)
1594                 return -ENOMEM;
1595
1596         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1597         key.type = BTRFS_DEV_ITEM_KEY;
1598         key.offset = device->devid;
1599
1600         ret = btrfs_insert_empty_item(trans, root, path, &key,
1601                                       sizeof(*dev_item));
1602         if (ret)
1603                 goto out;
1604
1605         leaf = path->nodes[0];
1606         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1607
1608         btrfs_set_device_id(leaf, dev_item, device->devid);
1609         btrfs_set_device_generation(leaf, dev_item, 0);
1610         btrfs_set_device_type(leaf, dev_item, device->type);
1611         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1612         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1613         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1614         btrfs_set_device_total_bytes(leaf, dev_item,
1615                                      btrfs_device_get_disk_total_bytes(device));
1616         btrfs_set_device_bytes_used(leaf, dev_item,
1617                                     btrfs_device_get_bytes_used(device));
1618         btrfs_set_device_group(leaf, dev_item, 0);
1619         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1620         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1621         btrfs_set_device_start_offset(leaf, dev_item, 0);
1622
1623         ptr = btrfs_device_uuid(dev_item);
1624         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1625         ptr = btrfs_device_fsid(dev_item);
1626         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1627         btrfs_mark_buffer_dirty(leaf);
1628
1629         ret = 0;
1630 out:
1631         btrfs_free_path(path);
1632         return ret;
1633 }
1634
1635 /*
1636  * Function to update ctime/mtime for a given device path.
1637  * Mainly used for ctime/mtime based probe like libblkid.
1638  */
1639 static void update_dev_time(char *path_name)
1640 {
1641         struct file *filp;
1642
1643         filp = filp_open(path_name, O_RDWR, 0);
1644         if (IS_ERR(filp))
1645                 return;
1646         file_update_time(filp);
1647         filp_close(filp, NULL);
1648 }
1649
1650 static int btrfs_rm_dev_item(struct btrfs_root *root,
1651                              struct btrfs_device *device)
1652 {
1653         int ret;
1654         struct btrfs_path *path;
1655         struct btrfs_key key;
1656         struct btrfs_trans_handle *trans;
1657
1658         root = root->fs_info->chunk_root;
1659
1660         path = btrfs_alloc_path();
1661         if (!path)
1662                 return -ENOMEM;
1663
1664         trans = btrfs_start_transaction(root, 0);
1665         if (IS_ERR(trans)) {
1666                 btrfs_free_path(path);
1667                 return PTR_ERR(trans);
1668         }
1669         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1670         key.type = BTRFS_DEV_ITEM_KEY;
1671         key.offset = device->devid;
1672
1673         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1674         if (ret < 0)
1675                 goto out;
1676
1677         if (ret > 0) {
1678                 ret = -ENOENT;
1679                 goto out;
1680         }
1681
1682         ret = btrfs_del_item(trans, root, path);
1683         if (ret)
1684                 goto out;
1685 out:
1686         btrfs_free_path(path);
1687         btrfs_commit_transaction(trans, root);
1688         return ret;
1689 }
1690
1691 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1692 {
1693         struct btrfs_device *device;
1694         struct btrfs_device *next_device;
1695         struct block_device *bdev;
1696         struct buffer_head *bh = NULL;
1697         struct btrfs_super_block *disk_super;
1698         struct btrfs_fs_devices *cur_devices;
1699         u64 all_avail;
1700         u64 devid;
1701         u64 num_devices;
1702         u8 *dev_uuid;
1703         unsigned seq;
1704         int ret = 0;
1705         bool clear_super = false;
1706
1707         mutex_lock(&uuid_mutex);
1708
1709         do {
1710                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1711
1712                 all_avail = root->fs_info->avail_data_alloc_bits |
1713                             root->fs_info->avail_system_alloc_bits |
1714                             root->fs_info->avail_metadata_alloc_bits;
1715         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1716
1717         num_devices = root->fs_info->fs_devices->num_devices;
1718         btrfs_dev_replace_lock(&root->fs_info->dev_replace, 0);
1719         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1720                 WARN_ON(num_devices < 1);
1721                 num_devices--;
1722         }
1723         btrfs_dev_replace_unlock(&root->fs_info->dev_replace, 0);
1724
1725         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1726                 ret = BTRFS_ERROR_DEV_RAID10_MIN_NOT_MET;
1727                 goto out;
1728         }
1729
1730         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1731                 ret = BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET;
1732                 goto out;
1733         }
1734
1735         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1736             root->fs_info->fs_devices->rw_devices <= 2) {
1737                 ret = BTRFS_ERROR_DEV_RAID5_MIN_NOT_MET;
1738                 goto out;
1739         }
1740         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1741             root->fs_info->fs_devices->rw_devices <= 3) {
1742                 ret = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET;
1743                 goto out;
1744         }
1745
1746         if (strcmp(device_path, "missing") == 0) {
1747                 struct list_head *devices;
1748                 struct btrfs_device *tmp;
1749
1750                 device = NULL;
1751                 devices = &root->fs_info->fs_devices->devices;
1752                 /*
1753                  * It is safe to read the devices since the volume_mutex
1754                  * is held.
1755                  */
1756                 list_for_each_entry(tmp, devices, dev_list) {
1757                         if (tmp->in_fs_metadata &&
1758                             !tmp->is_tgtdev_for_dev_replace &&
1759                             !tmp->bdev) {
1760                                 device = tmp;
1761                                 break;
1762                         }
1763                 }
1764                 bdev = NULL;
1765                 bh = NULL;
1766                 disk_super = NULL;
1767                 if (!device) {
1768                         ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
1769                         goto out;
1770                 }
1771         } else {
1772                 ret = btrfs_get_bdev_and_sb(device_path,
1773                                             FMODE_WRITE | FMODE_EXCL,
1774                                             root->fs_info->bdev_holder, 0,
1775                                             &bdev, &bh);
1776                 if (ret)
1777                         goto out;
1778                 disk_super = (struct btrfs_super_block *)bh->b_data;
1779                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1780                 dev_uuid = disk_super->dev_item.uuid;
1781                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1782                                            disk_super->fsid);
1783                 if (!device) {
1784                         ret = -ENOENT;
1785                         goto error_brelse;
1786                 }
1787         }
1788
1789         if (device->is_tgtdev_for_dev_replace) {
1790                 ret = BTRFS_ERROR_DEV_TGT_REPLACE;
1791                 goto error_brelse;
1792         }
1793
1794         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1795                 ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
1796                 goto error_brelse;
1797         }
1798
1799         if (device->writeable) {
1800                 lock_chunks(root);
1801                 list_del_init(&device->dev_alloc_list);
1802                 device->fs_devices->rw_devices--;
1803                 unlock_chunks(root);
1804                 clear_super = true;
1805         }
1806
1807         mutex_unlock(&uuid_mutex);
1808         ret = btrfs_shrink_device(device, 0);
1809         mutex_lock(&uuid_mutex);
1810         if (ret)
1811                 goto error_undo;
1812
1813         /*
1814          * TODO: the superblock still includes this device in its num_devices
1815          * counter although write_all_supers() is not locked out. This
1816          * could give a filesystem state which requires a degraded mount.
1817          */
1818         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1819         if (ret)
1820                 goto error_undo;
1821
1822         device->in_fs_metadata = 0;
1823         btrfs_scrub_cancel_dev(root->fs_info, device);
1824
1825         /*
1826          * the device list mutex makes sure that we don't change
1827          * the device list while someone else is writing out all
1828          * the device supers. Whoever is writing all supers, should
1829          * lock the device list mutex before getting the number of
1830          * devices in the super block (super_copy). Conversely,
1831          * whoever updates the number of devices in the super block
1832          * (super_copy) should hold the device list mutex.
1833          */
1834
1835         cur_devices = device->fs_devices;
1836         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1837         list_del_rcu(&device->dev_list);
1838
1839         device->fs_devices->num_devices--;
1840         device->fs_devices->total_devices--;
1841
1842         if (device->missing)
1843                 device->fs_devices->missing_devices--;
1844
1845         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1846                                  struct btrfs_device, dev_list);
1847         if (device->bdev == root->fs_info->sb->s_bdev)
1848                 root->fs_info->sb->s_bdev = next_device->bdev;
1849         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1850                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1851
1852         if (device->bdev) {
1853                 device->fs_devices->open_devices--;
1854                 /* remove sysfs entry */
1855                 btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
1856         }
1857
1858         call_rcu(&device->rcu, free_device);
1859
1860         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1861         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1862         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1863
1864         if (cur_devices->open_devices == 0) {
1865                 struct btrfs_fs_devices *fs_devices;
1866                 fs_devices = root->fs_info->fs_devices;
1867                 while (fs_devices) {
1868                         if (fs_devices->seed == cur_devices) {
1869                                 fs_devices->seed = cur_devices->seed;
1870                                 break;
1871                         }
1872                         fs_devices = fs_devices->seed;
1873                 }
1874                 cur_devices->seed = NULL;
1875                 __btrfs_close_devices(cur_devices);
1876                 free_fs_devices(cur_devices);
1877         }
1878
1879         root->fs_info->num_tolerated_disk_barrier_failures =
1880                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1881
1882         /*
1883          * at this point, the device is zero sized.  We want to
1884          * remove it from the devices list and zero out the old super
1885          */
1886         if (clear_super && disk_super) {
1887                 u64 bytenr;
1888                 int i;
1889
1890                 /* make sure this device isn't detected as part of
1891                  * the FS anymore
1892                  */
1893                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1894                 set_buffer_dirty(bh);
1895                 sync_dirty_buffer(bh);
1896
1897                 /* clear the mirror copies of super block on the disk
1898                  * being removed, 0th copy is been taken care above and
1899                  * the below would take of the rest
1900                  */
1901                 for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1902                         bytenr = btrfs_sb_offset(i);
1903                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
1904                                         i_size_read(bdev->bd_inode))
1905                                 break;
1906
1907                         brelse(bh);
1908                         bh = __bread(bdev, bytenr / 4096,
1909                                         BTRFS_SUPER_INFO_SIZE);
1910                         if (!bh)
1911                                 continue;
1912
1913                         disk_super = (struct btrfs_super_block *)bh->b_data;
1914
1915                         if (btrfs_super_bytenr(disk_super) != bytenr ||
1916                                 btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
1917                                 continue;
1918                         }
1919                         memset(&disk_super->magic, 0,
1920                                                 sizeof(disk_super->magic));
1921                         set_buffer_dirty(bh);
1922                         sync_dirty_buffer(bh);
1923                 }
1924         }
1925
1926         ret = 0;
1927
1928         if (bdev) {
1929                 /* Notify udev that device has changed */
1930                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1931
1932                 /* Update ctime/mtime for device path for libblkid */
1933                 update_dev_time(device_path);
1934         }
1935
1936 error_brelse:
1937         brelse(bh);
1938         if (bdev)
1939                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1940 out:
1941         mutex_unlock(&uuid_mutex);
1942         return ret;
1943 error_undo:
1944         if (device->writeable) {
1945                 lock_chunks(root);
1946                 list_add(&device->dev_alloc_list,
1947                          &root->fs_info->fs_devices->alloc_list);
1948                 device->fs_devices->rw_devices++;
1949                 unlock_chunks(root);
1950         }
1951         goto error_brelse;
1952 }
1953
1954 void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
1955                                         struct btrfs_device *srcdev)
1956 {
1957         struct btrfs_fs_devices *fs_devices;
1958
1959         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1960
1961         /*
1962          * in case of fs with no seed, srcdev->fs_devices will point
1963          * to fs_devices of fs_info. However when the dev being replaced is
1964          * a seed dev it will point to the seed's local fs_devices. In short
1965          * srcdev will have its correct fs_devices in both the cases.
1966          */
1967         fs_devices = srcdev->fs_devices;
1968
1969         list_del_rcu(&srcdev->dev_list);
1970         list_del_rcu(&srcdev->dev_alloc_list);
1971         fs_devices->num_devices--;
1972         if (srcdev->missing)
1973                 fs_devices->missing_devices--;
1974
1975         if (srcdev->writeable) {
1976                 fs_devices->rw_devices--;
1977                 /* zero out the old super if it is writable */
1978                 btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
1979         }
1980
1981         if (srcdev->bdev)
1982                 fs_devices->open_devices--;
1983 }
1984
1985 void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
1986                                       struct btrfs_device *srcdev)
1987 {
1988         struct btrfs_fs_devices *fs_devices = srcdev->fs_devices;
1989
1990         call_rcu(&srcdev->rcu, free_device);
1991
1992         /*
1993          * unless fs_devices is seed fs, num_devices shouldn't go
1994          * zero
1995          */
1996         BUG_ON(!fs_devices->num_devices && !fs_devices->seeding);
1997
1998         /* if this is no devs we rather delete the fs_devices */
1999         if (!fs_devices->num_devices) {
2000                 struct btrfs_fs_devices *tmp_fs_devices;
2001
2002                 tmp_fs_devices = fs_info->fs_devices;
2003                 while (tmp_fs_devices) {
2004                         if (tmp_fs_devices->seed == fs_devices) {
2005                                 tmp_fs_devices->seed = fs_devices->seed;
2006                                 break;
2007                         }
2008                         tmp_fs_devices = tmp_fs_devices->seed;
2009                 }
2010                 fs_devices->seed = NULL;
2011                 __btrfs_close_devices(fs_devices);
2012                 free_fs_devices(fs_devices);
2013         }
2014 }
2015
2016 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
2017                                       struct btrfs_device *tgtdev)
2018 {
2019         struct btrfs_device *next_device;
2020
2021         mutex_lock(&uuid_mutex);
2022         WARN_ON(!tgtdev);
2023         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2024
2025         btrfs_sysfs_rm_device_link(fs_info->fs_devices, tgtdev);
2026
2027         if (tgtdev->bdev) {
2028                 btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
2029                 fs_info->fs_devices->open_devices--;
2030         }
2031         fs_info->fs_devices->num_devices--;
2032
2033         next_device = list_entry(fs_info->fs_devices->devices.next,
2034                                  struct btrfs_device, dev_list);
2035         if (tgtdev->bdev == fs_info->sb->s_bdev)
2036                 fs_info->sb->s_bdev = next_device->bdev;
2037         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
2038                 fs_info->fs_devices->latest_bdev = next_device->bdev;
2039         list_del_rcu(&tgtdev->dev_list);
2040
2041         call_rcu(&tgtdev->rcu, free_device);
2042
2043         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2044         mutex_unlock(&uuid_mutex);
2045 }
2046
2047 static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
2048                                      struct btrfs_device **device)
2049 {
2050         int ret = 0;
2051         struct btrfs_super_block *disk_super;
2052         u64 devid;
2053         u8 *dev_uuid;
2054         struct block_device *bdev;
2055         struct buffer_head *bh;
2056
2057         *device = NULL;
2058         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
2059                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
2060         if (ret)
2061                 return ret;
2062         disk_super = (struct btrfs_super_block *)bh->b_data;
2063         devid = btrfs_stack_device_id(&disk_super->dev_item);
2064         dev_uuid = disk_super->dev_item.uuid;
2065         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2066                                     disk_super->fsid);
2067         brelse(bh);
2068         if (!*device)
2069                 ret = -ENOENT;
2070         blkdev_put(bdev, FMODE_READ);
2071         return ret;
2072 }
2073
2074 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
2075                                          char *device_path,
2076                                          struct btrfs_device **device)
2077 {
2078         *device = NULL;
2079         if (strcmp(device_path, "missing") == 0) {
2080                 struct list_head *devices;
2081                 struct btrfs_device *tmp;
2082
2083                 devices = &root->fs_info->fs_devices->devices;
2084                 /*
2085                  * It is safe to read the devices since the volume_mutex
2086                  * is held by the caller.
2087                  */
2088                 list_for_each_entry(tmp, devices, dev_list) {
2089                         if (tmp->in_fs_metadata && !tmp->bdev) {
2090                                 *device = tmp;
2091                                 break;
2092                         }
2093                 }
2094
2095                 if (!*device)
2096                         return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
2097
2098                 return 0;
2099         } else {
2100                 return btrfs_find_device_by_path(root, device_path, device);
2101         }
2102 }
2103
2104 /*
2105  * does all the dirty work required for changing file system's UUID.
2106  */
2107 static int btrfs_prepare_sprout(struct btrfs_root *root)
2108 {
2109         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2110         struct btrfs_fs_devices *old_devices;
2111         struct btrfs_fs_devices *seed_devices;
2112         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
2113         struct btrfs_device *device;
2114         u64 super_flags;
2115
2116         BUG_ON(!mutex_is_locked(&uuid_mutex));
2117         if (!fs_devices->seeding)
2118                 return -EINVAL;
2119
2120         seed_devices = __alloc_fs_devices();
2121         if (IS_ERR(seed_devices))
2122                 return PTR_ERR(seed_devices);
2123
2124         old_devices = clone_fs_devices(fs_devices);
2125         if (IS_ERR(old_devices)) {
2126                 kfree(seed_devices);
2127                 return PTR_ERR(old_devices);
2128         }
2129
2130         list_add(&old_devices->list, &fs_uuids);
2131
2132         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
2133         seed_devices->opened = 1;
2134         INIT_LIST_HEAD(&seed_devices->devices);
2135         INIT_LIST_HEAD(&seed_devices->alloc_list);
2136         mutex_init(&seed_devices->device_list_mutex);
2137
2138         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2139         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
2140                               synchronize_rcu);
2141         list_for_each_entry(device, &seed_devices->devices, dev_list)
2142                 device->fs_devices = seed_devices;
2143
2144         lock_chunks(root);
2145         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
2146         unlock_chunks(root);
2147
2148         fs_devices->seeding = 0;
2149         fs_devices->num_devices = 0;
2150         fs_devices->open_devices = 0;
2151         fs_devices->missing_devices = 0;
2152         fs_devices->rotating = 0;
2153         fs_devices->seed = seed_devices;
2154
2155         generate_random_uuid(fs_devices->fsid);
2156         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2157         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2158         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2159
2160         super_flags = btrfs_super_flags(disk_super) &
2161                       ~BTRFS_SUPER_FLAG_SEEDING;
2162         btrfs_set_super_flags(disk_super, super_flags);
2163
2164         return 0;
2165 }
2166
2167 /*
2168  * strore the expected generation for seed devices in device items.
2169  */
2170 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
2171                                struct btrfs_root *root)
2172 {
2173         struct btrfs_path *path;
2174         struct extent_buffer *leaf;
2175         struct btrfs_dev_item *dev_item;
2176         struct btrfs_device *device;
2177         struct btrfs_key key;
2178         u8 fs_uuid[BTRFS_UUID_SIZE];
2179         u8 dev_uuid[BTRFS_UUID_SIZE];
2180         u64 devid;
2181         int ret;
2182
2183         path = btrfs_alloc_path();
2184         if (!path)
2185                 return -ENOMEM;
2186
2187         root = root->fs_info->chunk_root;
2188         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2189         key.offset = 0;
2190         key.type = BTRFS_DEV_ITEM_KEY;
2191
2192         while (1) {
2193                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2194                 if (ret < 0)
2195                         goto error;
2196
2197                 leaf = path->nodes[0];
2198 next_slot:
2199                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
2200                         ret = btrfs_next_leaf(root, path);
2201                         if (ret > 0)
2202                                 break;
2203                         if (ret < 0)
2204                                 goto error;
2205                         leaf = path->nodes[0];
2206                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2207                         btrfs_release_path(path);
2208                         continue;
2209                 }
2210
2211                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2212                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
2213                     key.type != BTRFS_DEV_ITEM_KEY)
2214                         break;
2215
2216                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
2217                                           struct btrfs_dev_item);
2218                 devid = btrfs_device_id(leaf, dev_item);
2219                 read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
2220                                    BTRFS_UUID_SIZE);
2221                 read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
2222                                    BTRFS_UUID_SIZE);
2223                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2224                                            fs_uuid);
2225                 BUG_ON(!device); /* Logic error */
2226
2227                 if (device->fs_devices->seeding) {
2228                         btrfs_set_device_generation(leaf, dev_item,
2229                                                     device->generation);
2230                         btrfs_mark_buffer_dirty(leaf);
2231                 }
2232
2233                 path->slots[0]++;
2234                 goto next_slot;
2235         }
2236         ret = 0;
2237 error:
2238         btrfs_free_path(path);
2239         return ret;
2240 }
2241
2242 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
2243 {
2244         struct request_queue *q;
2245         struct btrfs_trans_handle *trans;
2246         struct btrfs_device *device;
2247         struct block_device *bdev;
2248         struct list_head *devices;
2249         struct super_block *sb = root->fs_info->sb;
2250         struct rcu_string *name;
2251         u64 tmp;
2252         int seeding_dev = 0;
2253         int ret = 0;
2254
2255         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
2256                 return -EROFS;
2257
2258         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2259                                   root->fs_info->bdev_holder);
2260         if (IS_ERR(bdev))
2261                 return PTR_ERR(bdev);
2262
2263         if (root->fs_info->fs_devices->seeding) {
2264                 seeding_dev = 1;
2265                 down_write(&sb->s_umount);
2266                 mutex_lock(&uuid_mutex);
2267         }
2268
2269         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2270
2271         devices = &root->fs_info->fs_devices->devices;
2272
2273         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2274         list_for_each_entry(device, devices, dev_list) {
2275                 if (device->bdev == bdev) {
2276                         ret = -EEXIST;
2277                         mutex_unlock(
2278                                 &root->fs_info->fs_devices->device_list_mutex);
2279                         goto error;
2280                 }
2281         }
2282         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2283
2284         device = btrfs_alloc_device(root->fs_info, NULL, NULL);
2285         if (IS_ERR(device)) {
2286                 /* we can safely leave the fs_devices entry around */
2287                 ret = PTR_ERR(device);
2288                 goto error;
2289         }
2290
2291         name = rcu_string_strdup(device_path, GFP_KERNEL);
2292         if (!name) {
2293                 kfree(device);
2294                 ret = -ENOMEM;
2295                 goto error;
2296         }
2297         rcu_assign_pointer(device->name, name);
2298
2299         trans = btrfs_start_transaction(root, 0);
2300         if (IS_ERR(trans)) {
2301                 rcu_string_free(device->name);
2302                 kfree(device);
2303                 ret = PTR_ERR(trans);
2304                 goto error;
2305         }
2306
2307         q = bdev_get_queue(bdev);
2308         if (blk_queue_discard(q))
2309                 device->can_discard = 1;
2310         device->writeable = 1;
2311         device->generation = trans->transid;
2312         device->io_width = root->sectorsize;
2313         device->io_align = root->sectorsize;
2314         device->sector_size = root->sectorsize;
2315         device->total_bytes = i_size_read(bdev->bd_inode);
2316         device->disk_total_bytes = device->total_bytes;
2317         device->commit_total_bytes = device->total_bytes;
2318         device->dev_root = root->fs_info->dev_root;
2319         device->bdev = bdev;
2320         device->in_fs_metadata = 1;
2321         device->is_tgtdev_for_dev_replace = 0;
2322         device->mode = FMODE_EXCL;
2323         device->dev_stats_valid = 1;
2324         set_blocksize(device->bdev, 4096);
2325
2326         if (seeding_dev) {
2327                 sb->s_flags &= ~MS_RDONLY;
2328                 ret = btrfs_prepare_sprout(root);
2329                 BUG_ON(ret); /* -ENOMEM */
2330         }
2331
2332         device->fs_devices = root->fs_info->fs_devices;
2333
2334         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2335         lock_chunks(root);
2336         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2337         list_add(&device->dev_alloc_list,
2338                  &root->fs_info->fs_devices->alloc_list);
2339         root->fs_info->fs_devices->num_devices++;
2340         root->fs_info->fs_devices->open_devices++;
2341         root->fs_info->fs_devices->rw_devices++;
2342         root->fs_info->fs_devices->total_devices++;
2343         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2344
2345         spin_lock(&root->fs_info->free_chunk_lock);
2346         root->fs_info->free_chunk_space += device->total_bytes;
2347         spin_unlock(&root->fs_info->free_chunk_lock);
2348
2349         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2350                 root->fs_info->fs_devices->rotating = 1;
2351
2352         tmp = btrfs_super_total_bytes(root->fs_info->super_copy);
2353         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2354                                     tmp + device->total_bytes);
2355
2356         tmp = btrfs_super_num_devices(root->fs_info->super_copy);
2357         btrfs_set_super_num_devices(root->fs_info->super_copy,
2358                                     tmp + 1);
2359
2360         /* add sysfs device entry */
2361         btrfs_sysfs_add_device_link(root->fs_info->fs_devices, device);
2362
2363         /*
2364          * we've got more storage, clear any full flags on the space
2365          * infos
2366          */
2367         btrfs_clear_space_info_full(root->fs_info);
2368
2369         unlock_chunks(root);
2370         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2371
2372         if (seeding_dev) {
2373                 lock_chunks(root);
2374                 ret = init_first_rw_device(trans, root, device);
2375                 unlock_chunks(root);
2376                 if (ret) {
2377                         btrfs_abort_transaction(trans, root, ret);
2378                         goto error_trans;
2379                 }
2380         }
2381
2382         ret = btrfs_add_device(trans, root, device);
2383         if (ret) {
2384                 btrfs_abort_transaction(trans, root, ret);
2385                 goto error_trans;
2386         }
2387
2388         if (seeding_dev) {
2389                 char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2390
2391                 ret = btrfs_finish_sprout(trans, root);
2392                 if (ret) {
2393                         btrfs_abort_transaction(trans, root, ret);
2394                         goto error_trans;
2395                 }
2396
2397                 /* Sprouting would change fsid of the mounted root,
2398                  * so rename the fsid on the sysfs
2399                  */
2400                 snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
2401                                                 root->fs_info->fsid);
2402                 if (kobject_rename(&root->fs_info->fs_devices->fsid_kobj,
2403                                                                 fsid_buf))
2404                         btrfs_warn(root->fs_info,
2405                                 "sysfs: failed to create fsid for sprout");
2406         }
2407
2408         root->fs_info->num_tolerated_disk_barrier_failures =
2409                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2410         ret = btrfs_commit_transaction(trans, root);
2411
2412         if (seeding_dev) {
2413                 mutex_unlock(&uuid_mutex);
2414                 up_write(&sb->s_umount);
2415
2416                 if (ret) /* transaction commit */
2417                         return ret;
2418
2419                 ret = btrfs_relocate_sys_chunks(root);
2420                 if (ret < 0)
2421                         btrfs_std_error(root->fs_info, ret,
2422                                     "Failed to relocate sys chunks after "
2423                                     "device initialization. This can be fixed "
2424                                     "using the \"btrfs balance\" command.");
2425                 trans = btrfs_attach_transaction(root);
2426                 if (IS_ERR(trans)) {
2427                         if (PTR_ERR(trans) == -ENOENT)
2428                                 return 0;
2429                         return PTR_ERR(trans);
2430                 }
2431                 ret = btrfs_commit_transaction(trans, root);
2432         }
2433
2434         /* Update ctime/mtime for libblkid */
2435         update_dev_time(device_path);
2436         return ret;
2437
2438 error_trans:
2439         btrfs_end_transaction(trans, root);
2440         rcu_string_free(device->name);
2441         btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
2442         kfree(device);
2443 error:
2444         blkdev_put(bdev, FMODE_EXCL);
2445         if (seeding_dev) {
2446                 mutex_unlock(&uuid_mutex);
2447                 up_write(&sb->s_umount);
2448         }
2449         return ret;
2450 }
2451
2452 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2453                                   struct btrfs_device *srcdev,
2454                                   struct btrfs_device **device_out)
2455 {
2456         struct request_queue *q;
2457         struct btrfs_device *device;
2458         struct block_device *bdev;
2459         struct btrfs_fs_info *fs_info = root->fs_info;
2460         struct list_head *devices;
2461         struct rcu_string *name;
2462         u64 devid = BTRFS_DEV_REPLACE_DEVID;
2463         int ret = 0;
2464
2465         *device_out = NULL;
2466         if (fs_info->fs_devices->seeding) {
2467                 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
2468                 return -EINVAL;
2469         }
2470
2471         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2472                                   fs_info->bdev_holder);
2473         if (IS_ERR(bdev)) {
2474                 btrfs_err(fs_info, "target device %s is invalid!", device_path);
2475                 return PTR_ERR(bdev);
2476         }
2477
2478         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2479
2480         devices = &fs_info->fs_devices->devices;
2481         list_for_each_entry(device, devices, dev_list) {
2482                 if (device->bdev == bdev) {
2483                         btrfs_err(fs_info, "target device is in the filesystem!");
2484                         ret = -EEXIST;
2485                         goto error;
2486                 }
2487         }
2488
2489
2490         if (i_size_read(bdev->bd_inode) <
2491             btrfs_device_get_total_bytes(srcdev)) {
2492                 btrfs_err(fs_info, "target device is smaller than source device!");
2493                 ret = -EINVAL;
2494                 goto error;
2495         }
2496
2497
2498         device = btrfs_alloc_device(NULL, &devid, NULL);
2499         if (IS_ERR(device)) {
2500                 ret = PTR_ERR(device);
2501                 goto error;
2502         }
2503
2504         name = rcu_string_strdup(device_path, GFP_NOFS);
2505         if (!name) {
2506                 kfree(device);
2507                 ret = -ENOMEM;
2508                 goto error;
2509         }
2510         rcu_assign_pointer(device->name, name);
2511
2512         q = bdev_get_queue(bdev);
2513         if (blk_queue_discard(q))
2514                 device->can_discard = 1;
2515         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2516         device->writeable = 1;
2517         device->generation = 0;
2518         device->io_width = root->sectorsize;
2519         device->io_align = root->sectorsize;
2520         device->sector_size = root->sectorsize;
2521         device->total_bytes = btrfs_device_get_total_bytes(srcdev);
2522         device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
2523         device->bytes_used = btrfs_device_get_bytes_used(srcdev);
2524         ASSERT(list_empty(&srcdev->resized_list));
2525         device->commit_total_bytes = srcdev->commit_total_bytes;
2526         device->commit_bytes_used = device->bytes_used;
2527         device->dev_root = fs_info->dev_root;
2528         device->bdev = bdev;
2529         device->in_fs_metadata = 1;
2530         device->is_tgtdev_for_dev_replace = 1;
2531         device->mode = FMODE_EXCL;
2532         device->dev_stats_valid = 1;
2533         set_blocksize(device->bdev, 4096);
2534         device->fs_devices = fs_info->fs_devices;
2535         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2536         fs_info->fs_devices->num_devices++;
2537         fs_info->fs_devices->open_devices++;
2538         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2539
2540         *device_out = device;
2541         return ret;
2542
2543 error:
2544         blkdev_put(bdev, FMODE_EXCL);
2545         return ret;
2546 }
2547
2548 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2549                                               struct btrfs_device *tgtdev)
2550 {
2551         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2552         tgtdev->io_width = fs_info->dev_root->sectorsize;
2553         tgtdev->io_align = fs_info->dev_root->sectorsize;
2554         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2555         tgtdev->dev_root = fs_info->dev_root;
2556         tgtdev->in_fs_metadata = 1;
2557 }
2558
2559 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2560                                         struct btrfs_device *device)
2561 {
2562         int ret;
2563         struct btrfs_path *path;
2564         struct btrfs_root *root;
2565         struct btrfs_dev_item *dev_item;
2566         struct extent_buffer *leaf;
2567         struct btrfs_key key;
2568
2569         root = device->dev_root->fs_info->chunk_root;
2570
2571         path = btrfs_alloc_path();
2572         if (!path)
2573                 return -ENOMEM;
2574
2575         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2576         key.type = BTRFS_DEV_ITEM_KEY;
2577         key.offset = device->devid;
2578
2579         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2580         if (ret < 0)
2581                 goto out;
2582
2583         if (ret > 0) {
2584                 ret = -ENOENT;
2585                 goto out;
2586         }
2587
2588         leaf = path->nodes[0];
2589         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2590
2591         btrfs_set_device_id(leaf, dev_item, device->devid);
2592         btrfs_set_device_type(leaf, dev_item, device->type);
2593         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2594         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2595         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2596         btrfs_set_device_total_bytes(leaf, dev_item,
2597                                      btrfs_device_get_disk_total_bytes(device));
2598         btrfs_set_device_bytes_used(leaf, dev_item,
2599                                     btrfs_device_get_bytes_used(device));
2600         btrfs_mark_buffer_dirty(leaf);
2601
2602 out:
2603         btrfs_free_path(path);
2604         return ret;
2605 }
2606
2607 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2608                       struct btrfs_device *device, u64 new_size)
2609 {
2610         struct btrfs_super_block *super_copy =
2611                 device->dev_root->fs_info->super_copy;
2612         struct btrfs_fs_devices *fs_devices;
2613         u64 old_total;
2614         u64 diff;
2615
2616         if (!device->writeable)
2617                 return -EACCES;
2618
2619         lock_chunks(device->dev_root);
2620         old_total = btrfs_super_total_bytes(super_copy);
2621         diff = new_size - device->total_bytes;
2622
2623         if (new_size <= device->total_bytes ||
2624             device->is_tgtdev_for_dev_replace) {
2625                 unlock_chunks(device->dev_root);
2626                 return -EINVAL;
2627         }
2628
2629         fs_devices = device->dev_root->fs_info->fs_devices;
2630
2631         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2632         device->fs_devices->total_rw_bytes += diff;
2633
2634         btrfs_device_set_total_bytes(device, new_size);
2635         btrfs_device_set_disk_total_bytes(device, new_size);
2636         btrfs_clear_space_info_full(device->dev_root->fs_info);
2637         if (list_empty(&device->resized_list))
2638                 list_add_tail(&device->resized_list,
2639                               &fs_devices->resized_devices);
2640         unlock_chunks(device->dev_root);
2641
2642         return btrfs_update_device(trans, device);
2643 }
2644
2645 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2646                             struct btrfs_root *root, u64 chunk_objectid,
2647                             u64 chunk_offset)
2648 {
2649         int ret;
2650         struct btrfs_path *path;
2651         struct btrfs_key key;
2652
2653         root = root->fs_info->chunk_root;
2654         path = btrfs_alloc_path();
2655         if (!path)
2656                 return -ENOMEM;
2657
2658         key.objectid = chunk_objectid;
2659         key.offset = chunk_offset;
2660         key.type = BTRFS_CHUNK_ITEM_KEY;
2661
2662         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2663         if (ret < 0)
2664                 goto out;
2665         else if (ret > 0) { /* Logic error or corruption */
2666                 btrfs_std_error(root->fs_info, -ENOENT,
2667                             "Failed lookup while freeing chunk.");
2668                 ret = -ENOENT;
2669                 goto out;
2670         }
2671
2672         ret = btrfs_del_item(trans, root, path);
2673         if (ret < 0)
2674                 btrfs_std_error(root->fs_info, ret,
2675                             "Failed to delete chunk item.");
2676 out:
2677         btrfs_free_path(path);
2678         return ret;
2679 }
2680
2681 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2682                         chunk_offset)
2683 {
2684         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2685         struct btrfs_disk_key *disk_key;
2686         struct btrfs_chunk *chunk;
2687         u8 *ptr;
2688         int ret = 0;
2689         u32 num_stripes;
2690         u32 array_size;
2691         u32 len = 0;
2692         u32 cur;
2693         struct btrfs_key key;
2694
2695         lock_chunks(root);
2696         array_size = btrfs_super_sys_array_size(super_copy);
2697
2698         ptr = super_copy->sys_chunk_array;
2699         cur = 0;
2700
2701         while (cur < array_size) {
2702                 disk_key = (struct btrfs_disk_key *)ptr;
2703                 btrfs_disk_key_to_cpu(&key, disk_key);
2704
2705                 len = sizeof(*disk_key);
2706
2707                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2708                         chunk = (struct btrfs_chunk *)(ptr + len);
2709                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2710                         len += btrfs_chunk_item_size(num_stripes);
2711                 } else {
2712                         ret = -EIO;
2713                         break;
2714                 }
2715                 if (key.objectid == chunk_objectid &&
2716                     key.offset == chunk_offset) {
2717                         memmove(ptr, ptr + len, array_size - (cur + len));
2718                         array_size -= len;
2719                         btrfs_set_super_sys_array_size(super_copy, array_size);
2720                 } else {
2721                         ptr += len;
2722                         cur += len;
2723                 }
2724         }
2725         unlock_chunks(root);
2726         return ret;
2727 }
2728
2729 int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
2730                        struct btrfs_root *root, u64 chunk_offset)
2731 {
2732         struct extent_map_tree *em_tree;
2733         struct extent_map *em;
2734         struct btrfs_root *extent_root = root->fs_info->extent_root;
2735         struct map_lookup *map;
2736         u64 dev_extent_len = 0;
2737         u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2738         int i, ret = 0;
2739
2740         /* Just in case */
2741         root = root->fs_info->chunk_root;
2742         em_tree = &root->fs_info->mapping_tree.map_tree;
2743
2744         read_lock(&em_tree->lock);
2745         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2746         read_unlock(&em_tree->lock);
2747
2748         if (!em || em->start > chunk_offset ||
2749             em->start + em->len < chunk_offset) {
2750                 /*
2751                  * This is a logic error, but we don't want to just rely on the
2752                  * user having built with ASSERT enabled, so if ASSERT doesn't
2753                  * do anything we still error out.
2754                  */
2755                 ASSERT(0);
2756                 if (em)
2757                         free_extent_map(em);
2758                 return -EINVAL;
2759         }
2760         map = em->map_lookup;
2761         lock_chunks(root->fs_info->chunk_root);
2762         check_system_chunk(trans, extent_root, map->type);
2763         unlock_chunks(root->fs_info->chunk_root);
2764
2765         for (i = 0; i < map->num_stripes; i++) {
2766                 struct btrfs_device *device = map->stripes[i].dev;
2767                 ret = btrfs_free_dev_extent(trans, device,
2768                                             map->stripes[i].physical,
2769                                             &dev_extent_len);
2770                 if (ret) {
2771                         btrfs_abort_transaction(trans, root, ret);
2772                         goto out;
2773                 }
2774
2775                 if (device->bytes_used > 0) {
2776                         lock_chunks(root);
2777                         btrfs_device_set_bytes_used(device,
2778                                         device->bytes_used - dev_extent_len);
2779                         spin_lock(&root->fs_info->free_chunk_lock);
2780                         root->fs_info->free_chunk_space += dev_extent_len;
2781                         spin_unlock(&root->fs_info->free_chunk_lock);
2782                         btrfs_clear_space_info_full(root->fs_info);
2783                         unlock_chunks(root);
2784                 }
2785
2786                 if (map->stripes[i].dev) {
2787                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2788                         if (ret) {
2789                                 btrfs_abort_transaction(trans, root, ret);
2790                                 goto out;
2791                         }
2792                 }
2793         }
2794         ret = btrfs_free_chunk(trans, root, chunk_objectid, chunk_offset);
2795         if (ret) {
2796                 btrfs_abort_transaction(trans, root, ret);
2797                 goto out;
2798         }
2799
2800         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2801
2802         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2803                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2804                 if (ret) {
2805                         btrfs_abort_transaction(trans, root, ret);
2806                         goto out;
2807                 }
2808         }
2809
2810         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset, em);
2811         if (ret) {
2812                 btrfs_abort_transaction(trans, extent_root, ret);
2813                 goto out;
2814         }
2815
2816 out:
2817         /* once for us */
2818         free_extent_map(em);
2819         return ret;
2820 }
2821
2822 static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
2823 {
2824         struct btrfs_root *extent_root;
2825         struct btrfs_trans_handle *trans;
2826         int ret;
2827
2828         root = root->fs_info->chunk_root;
2829         extent_root = root->fs_info->extent_root;
2830
2831         /*
2832          * Prevent races with automatic removal of unused block groups.
2833          * After we relocate and before we remove the chunk with offset
2834          * chunk_offset, automatic removal of the block group can kick in,
2835          * resulting in a failure when calling btrfs_remove_chunk() below.
2836          *
2837          * Make sure to acquire this mutex before doing a tree search (dev
2838          * or chunk trees) to find chunks. Otherwise the cleaner kthread might
2839          * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after
2840          * we release the path used to search the chunk/dev tree and before
2841          * the current task acquires this mutex and calls us.
2842          */
2843         ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex));
2844
2845         ret = btrfs_can_relocate(extent_root, chunk_offset);
2846         if (ret)
2847                 return -ENOSPC;
2848
2849         /* step one, relocate all the extents inside this chunk */
2850         btrfs_scrub_pause(root);
2851         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2852         btrfs_scrub_continue(root);
2853         if (ret)
2854                 return ret;
2855
2856         trans = btrfs_start_trans_remove_block_group(root->fs_info,
2857                                                      chunk_offset);
2858         if (IS_ERR(trans)) {
2859                 ret = PTR_ERR(trans);
2860                 btrfs_std_error(root->fs_info, ret, NULL);
2861                 return ret;
2862         }
2863
2864         /*
2865          * step two, delete the device extents and the
2866          * chunk tree entries
2867          */
2868         ret = btrfs_remove_chunk(trans, root, chunk_offset);
2869         btrfs_end_transaction(trans, root);
2870         return ret;
2871 }
2872
2873 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2874 {
2875         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2876         struct btrfs_path *path;
2877         struct extent_buffer *leaf;
2878         struct btrfs_chunk *chunk;
2879         struct btrfs_key key;
2880         struct btrfs_key found_key;
2881         u64 chunk_type;
2882         bool retried = false;
2883         int failed = 0;
2884         int ret;
2885
2886         path = btrfs_alloc_path();
2887         if (!path)
2888                 return -ENOMEM;
2889
2890 again:
2891         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2892         key.offset = (u64)-1;
2893         key.type = BTRFS_CHUNK_ITEM_KEY;
2894
2895         while (1) {
2896                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
2897                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2898                 if (ret < 0) {
2899                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2900                         goto error;
2901                 }
2902                 BUG_ON(ret == 0); /* Corruption */
2903
2904                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2905                                           key.type);
2906                 if (ret)
2907                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2908                 if (ret < 0)
2909                         goto error;
2910                 if (ret > 0)
2911                         break;
2912
2913                 leaf = path->nodes[0];
2914                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2915
2916                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2917                                        struct btrfs_chunk);
2918                 chunk_type = btrfs_chunk_type(leaf, chunk);
2919                 btrfs_release_path(path);
2920
2921                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2922                         ret = btrfs_relocate_chunk(chunk_root,
2923                                                    found_key.offset);
2924                         if (ret == -ENOSPC)
2925                                 failed++;
2926                         else
2927                                 BUG_ON(ret);
2928                 }
2929                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2930
2931                 if (found_key.offset == 0)
2932                         break;
2933                 key.offset = found_key.offset - 1;
2934         }
2935         ret = 0;
2936         if (failed && !retried) {
2937                 failed = 0;
2938                 retried = true;
2939                 goto again;
2940         } else if (WARN_ON(failed && retried)) {
2941                 ret = -ENOSPC;
2942         }
2943 error:
2944         btrfs_free_path(path);
2945         return ret;
2946 }
2947
2948 static int insert_balance_item(struct btrfs_root *root,
2949                                struct btrfs_balance_control *bctl)
2950 {
2951         struct btrfs_trans_handle *trans;
2952         struct btrfs_balance_item *item;
2953         struct btrfs_disk_balance_args disk_bargs;
2954         struct btrfs_path *path;
2955         struct extent_buffer *leaf;
2956         struct btrfs_key key;
2957         int ret, err;
2958
2959         path = btrfs_alloc_path();
2960         if (!path)
2961                 return -ENOMEM;
2962
2963         trans = btrfs_start_transaction(root, 0);
2964         if (IS_ERR(trans)) {
2965                 btrfs_free_path(path);
2966                 return PTR_ERR(trans);
2967         }
2968
2969         key.objectid = BTRFS_BALANCE_OBJECTID;
2970         key.type = BTRFS_TEMPORARY_ITEM_KEY;
2971         key.offset = 0;
2972
2973         ret = btrfs_insert_empty_item(trans, root, path, &key,
2974                                       sizeof(*item));
2975         if (ret)
2976                 goto out;
2977
2978         leaf = path->nodes[0];
2979         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2980
2981         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2982
2983         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2984         btrfs_set_balance_data(leaf, item, &disk_bargs);
2985         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2986         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2987         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2988         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2989
2990         btrfs_set_balance_flags(leaf, item, bctl->flags);
2991
2992         btrfs_mark_buffer_dirty(leaf);
2993 out:
2994         btrfs_free_path(path);
2995         err = btrfs_commit_transaction(trans, root);
2996         if (err && !ret)
2997                 ret = err;
2998         return ret;
2999 }
3000
3001 static int del_balance_item(struct btrfs_root *root)
3002 {
3003         struct btrfs_trans_handle *trans;
3004         struct btrfs_path *path;
3005         struct btrfs_key key;
3006         int ret, err;
3007
3008         path = btrfs_alloc_path();
3009         if (!path)
3010                 return -ENOMEM;
3011
3012         trans = btrfs_start_transaction(root, 0);
3013         if (IS_ERR(trans)) {
3014                 btrfs_free_path(path);
3015                 return PTR_ERR(trans);
3016         }
3017
3018         key.objectid = BTRFS_BALANCE_OBJECTID;
3019         key.type = BTRFS_TEMPORARY_ITEM_KEY;
3020         key.offset = 0;
3021
3022         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3023         if (ret < 0)
3024                 goto out;
3025         if (ret > 0) {
3026                 ret = -ENOENT;
3027                 goto out;
3028         }
3029
3030         ret = btrfs_del_item(trans, root, path);
3031 out:
3032         btrfs_free_path(path);
3033         err = btrfs_commit_transaction(trans, root);
3034         if (err && !ret)
3035                 ret = err;
3036         return ret;
3037 }
3038
3039 /*
3040  * This is a heuristic used to reduce the number of chunks balanced on
3041  * resume after balance was interrupted.
3042  */
3043 static void update_balance_args(struct btrfs_balance_control *bctl)
3044 {
3045         /*
3046          * Turn on soft mode for chunk types that were being converted.
3047          */
3048         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
3049                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
3050         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
3051                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
3052         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
3053                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
3054
3055         /*
3056          * Turn on usage filter if is not already used.  The idea is
3057          * that chunks that we have already balanced should be
3058          * reasonably full.  Don't do it for chunks that are being
3059          * converted - that will keep us from relocating unconverted
3060          * (albeit full) chunks.
3061          */
3062         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3063             !(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3064             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3065                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
3066                 bctl->data.usage = 90;
3067         }
3068         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3069             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3070             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3071                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
3072                 bctl->sys.usage = 90;
3073         }
3074         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3075             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3076             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3077                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
3078                 bctl->meta.usage = 90;
3079         }
3080 }
3081
3082 /*
3083  * Should be called with both balance and volume mutexes held to
3084  * serialize other volume operations (add_dev/rm_dev/resize) with
3085  * restriper.  Same goes for unset_balance_control.
3086  */
3087 static void set_balance_control(struct btrfs_balance_control *bctl)
3088 {
3089         struct btrfs_fs_info *fs_info = bctl->fs_info;
3090
3091         BUG_ON(fs_info->balance_ctl);
3092
3093         spin_lock(&fs_info->balance_lock);
3094         fs_info->balance_ctl = bctl;
3095         spin_unlock(&fs_info->balance_lock);
3096 }
3097
3098 static void unset_balance_control(struct btrfs_fs_info *fs_info)
3099 {
3100         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3101
3102         BUG_ON(!fs_info->balance_ctl);
3103
3104         spin_lock(&fs_info->balance_lock);
3105         fs_info->balance_ctl = NULL;
3106         spin_unlock(&fs_info->balance_lock);
3107
3108         kfree(bctl);
3109 }
3110
3111 /*
3112  * Balance filters.  Return 1 if chunk should be filtered out
3113  * (should not be balanced).
3114  */
3115 static int chunk_profiles_filter(u64 chunk_type,
3116                                  struct btrfs_balance_args *bargs)
3117 {
3118         chunk_type = chunk_to_extended(chunk_type) &
3119                                 BTRFS_EXTENDED_PROFILE_MASK;
3120
3121         if (bargs->profiles & chunk_type)
3122                 return 0;
3123
3124         return 1;
3125 }
3126
3127 static int chunk_usage_range_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
3128                               struct btrfs_balance_args *bargs)
3129 {
3130         struct btrfs_block_group_cache *cache;
3131         u64 chunk_used;
3132         u64 user_thresh_min;
3133         u64 user_thresh_max;
3134         int ret = 1;
3135
3136         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3137         chunk_used = btrfs_block_group_used(&cache->item);
3138
3139         if (bargs->usage_min == 0)
3140                 user_thresh_min = 0;
3141         else
3142                 user_thresh_min = div_factor_fine(cache->key.offset,
3143                                         bargs->usage_min);
3144
3145         if (bargs->usage_max == 0)
3146                 user_thresh_max = 1;
3147         else if (bargs->usage_max > 100)
3148                 user_thresh_max = cache->key.offset;
3149         else
3150                 user_thresh_max = div_factor_fine(cache->key.offset,
3151                                         bargs->usage_max);
3152
3153         if (user_thresh_min <= chunk_used && chunk_used < user_thresh_max)
3154                 ret = 0;
3155
3156         btrfs_put_block_group(cache);
3157         return ret;
3158 }
3159
3160 static int chunk_usage_filter(struct btrfs_fs_info *fs_info,
3161                 u64 chunk_offset, struct btrfs_balance_args *bargs)
3162 {
3163         struct btrfs_block_group_cache *cache;
3164         u64 chunk_used, user_thresh;
3165         int ret = 1;
3166
3167         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3168         chunk_used = btrfs_block_group_used(&cache->item);
3169
3170         if (bargs->usage_min == 0)
3171                 user_thresh = 1;
3172         else if (bargs->usage > 100)
3173                 user_thresh = cache->key.offset;
3174         else
3175                 user_thresh = div_factor_fine(cache->key.offset,
3176                                               bargs->usage);
3177
3178         if (chunk_used < user_thresh)
3179                 ret = 0;
3180
3181         btrfs_put_block_group(cache);
3182         return ret;
3183 }
3184
3185 static int chunk_devid_filter(struct extent_buffer *leaf,
3186                               struct btrfs_chunk *chunk,
3187                               struct btrfs_balance_args *bargs)
3188 {
3189         struct btrfs_stripe *stripe;
3190         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3191         int i;
3192
3193         for (i = 0; i < num_stripes; i++) {
3194                 stripe = btrfs_stripe_nr(chunk, i);
3195                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
3196                         return 0;
3197         }
3198
3199         return 1;
3200 }
3201
3202 /* [pstart, pend) */
3203 static int chunk_drange_filter(struct extent_buffer *leaf,
3204                                struct btrfs_chunk *chunk,
3205                                u64 chunk_offset,
3206                                struct btrfs_balance_args *bargs)
3207 {
3208         struct btrfs_stripe *stripe;
3209         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3210         u64 stripe_offset;
3211         u64 stripe_length;
3212         int factor;
3213         int i;
3214
3215         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
3216                 return 0;
3217
3218         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
3219              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
3220                 factor = num_stripes / 2;
3221         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
3222                 factor = num_stripes - 1;
3223         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
3224                 factor = num_stripes - 2;
3225         } else {
3226                 factor = num_stripes;
3227         }
3228
3229         for (i = 0; i < num_stripes; i++) {
3230                 stripe = btrfs_stripe_nr(chunk, i);
3231                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
3232                         continue;
3233
3234                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
3235                 stripe_length = btrfs_chunk_length(leaf, chunk);
3236                 stripe_length = div_u64(stripe_length, factor);
3237
3238                 if (stripe_offset < bargs->pend &&
3239                     stripe_offset + stripe_length > bargs->pstart)
3240                         return 0;
3241         }
3242
3243         return 1;
3244 }
3245
3246 /* [vstart, vend) */
3247 static int chunk_vrange_filter(struct extent_buffer *leaf,
3248                                struct btrfs_chunk *chunk,
3249                                u64 chunk_offset,
3250                                struct btrfs_balance_args *bargs)
3251 {
3252         if (chunk_offset < bargs->vend &&
3253             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
3254                 /* at least part of the chunk is inside this vrange */
3255                 return 0;
3256
3257         return 1;
3258 }
3259
3260 static int chunk_stripes_range_filter(struct extent_buffer *leaf,
3261                                struct btrfs_chunk *chunk,
3262                                struct btrfs_balance_args *bargs)
3263 {
3264         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3265
3266         if (bargs->stripes_min <= num_stripes
3267                         && num_stripes <= bargs->stripes_max)
3268                 return 0;
3269
3270         return 1;
3271 }
3272
3273 static int chunk_soft_convert_filter(u64 chunk_type,
3274                                      struct btrfs_balance_args *bargs)
3275 {
3276         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
3277                 return 0;
3278
3279         chunk_type = chunk_to_extended(chunk_type) &
3280                                 BTRFS_EXTENDED_PROFILE_MASK;
3281
3282         if (bargs->target == chunk_type)
3283                 return 1;
3284
3285         return 0;
3286 }
3287
3288 static int should_balance_chunk(struct btrfs_root *root,
3289                                 struct extent_buffer *leaf,
3290                                 struct btrfs_chunk *chunk, u64 chunk_offset)
3291 {
3292         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3293         struct btrfs_balance_args *bargs = NULL;
3294         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
3295
3296         /* type filter */
3297         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
3298               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
3299                 return 0;
3300         }
3301
3302         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3303                 bargs = &bctl->data;
3304         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3305                 bargs = &bctl->sys;
3306         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3307                 bargs = &bctl->meta;
3308
3309         /* profiles filter */
3310         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
3311             chunk_profiles_filter(chunk_type, bargs)) {
3312                 return 0;
3313         }
3314
3315         /* usage filter */
3316         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
3317             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
3318                 return 0;
3319         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3320             chunk_usage_range_filter(bctl->fs_info, chunk_offset, bargs)) {
3321                 return 0;
3322         }
3323
3324         /* devid filter */
3325         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
3326             chunk_devid_filter(leaf, chunk, bargs)) {
3327                 return 0;
3328         }
3329
3330         /* drange filter, makes sense only with devid filter */
3331         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
3332             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
3333                 return 0;
3334         }
3335
3336         /* vrange filter */
3337         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
3338             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
3339                 return 0;
3340         }
3341
3342         /* stripes filter */
3343         if ((bargs->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) &&
3344             chunk_stripes_range_filter(leaf, chunk, bargs)) {
3345                 return 0;
3346         }
3347
3348         /* soft profile changing mode */
3349         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
3350             chunk_soft_convert_filter(chunk_type, bargs)) {
3351                 return 0;
3352         }
3353
3354         /*
3355          * limited by count, must be the last filter
3356          */
3357         if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT)) {
3358                 if (bargs->limit == 0)
3359                         return 0;
3360                 else
3361                         bargs->limit--;
3362         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)) {
3363                 /*
3364                  * Same logic as the 'limit' filter; the minimum cannot be
3365                  * determined here because we do not have the global informatoin
3366                  * about the count of all chunks that satisfy the filters.
3367                  */
3368                 if (bargs->limit_max == 0)
3369                         return 0;
3370                 else
3371                         bargs->limit_max--;
3372         }
3373
3374         return 1;
3375 }
3376
3377 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
3378 {
3379         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3380         struct btrfs_root *chunk_root = fs_info->chunk_root;
3381         struct btrfs_root *dev_root = fs_info->dev_root;
3382         struct list_head *devices;
3383         struct btrfs_device *device;
3384         u64 old_size;
3385         u64 size_to_free;
3386         u64 chunk_type;
3387         struct btrfs_chunk *chunk;
3388         struct btrfs_path *path;
3389         struct btrfs_key key;
3390         struct btrfs_key found_key;
3391         struct btrfs_trans_handle *trans;
3392         struct extent_buffer *leaf;
3393         int slot;
3394         int ret;
3395         int enospc_errors = 0;
3396         bool counting = true;
3397         /* The single value limit and min/max limits use the same bytes in the */
3398         u64 limit_data = bctl->data.limit;
3399         u64 limit_meta = bctl->meta.limit;
3400         u64 limit_sys = bctl->sys.limit;
3401         u32 count_data = 0;
3402         u32 count_meta = 0;
3403         u32 count_sys = 0;
3404         int chunk_reserved = 0;
3405         u64 bytes_used = 0;
3406
3407         /* step one make some room on all the devices */
3408         devices = &fs_info->fs_devices->devices;
3409         list_for_each_entry(device, devices, dev_list) {
3410                 old_size = btrfs_device_get_total_bytes(device);
3411                 size_to_free = div_factor(old_size, 1);
3412                 size_to_free = min_t(u64, size_to_free, SZ_1M);
3413                 if (!device->writeable ||
3414                     btrfs_device_get_total_bytes(device) -
3415                     btrfs_device_get_bytes_used(device) > size_to_free ||
3416                     device->is_tgtdev_for_dev_replace)
3417                         continue;
3418
3419                 ret = btrfs_shrink_device(device, old_size - size_to_free);
3420                 if (ret == -ENOSPC)
3421                         break;
3422                 BUG_ON(ret);
3423
3424                 trans = btrfs_start_transaction(dev_root, 0);
3425                 BUG_ON(IS_ERR(trans));
3426
3427                 ret = btrfs_grow_device(trans, device, old_size);
3428                 BUG_ON(ret);
3429
3430                 btrfs_end_transaction(trans, dev_root);
3431         }
3432
3433         /* step two, relocate all the chunks */
3434         path = btrfs_alloc_path();
3435         if (!path) {
3436                 ret = -ENOMEM;
3437                 goto error;
3438         }
3439
3440         /* zero out stat counters */
3441         spin_lock(&fs_info->balance_lock);
3442         memset(&bctl->stat, 0, sizeof(bctl->stat));
3443         spin_unlock(&fs_info->balance_lock);
3444 again:
3445         if (!counting) {
3446                 /*
3447                  * The single value limit and min/max limits use the same bytes
3448                  * in the
3449                  */
3450                 bctl->data.limit = limit_data;
3451                 bctl->meta.limit = limit_meta;
3452                 bctl->sys.limit = limit_sys;
3453         }
3454         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3455         key.offset = (u64)-1;
3456         key.type = BTRFS_CHUNK_ITEM_KEY;
3457
3458         while (1) {
3459                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
3460                     atomic_read(&fs_info->balance_cancel_req)) {
3461                         ret = -ECANCELED;
3462                         goto error;
3463                 }
3464
3465                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
3466                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
3467                 if (ret < 0) {
3468                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3469                         goto error;
3470                 }
3471
3472                 /*
3473                  * this shouldn't happen, it means the last relocate
3474                  * failed
3475                  */
3476                 if (ret == 0)
3477                         BUG(); /* FIXME break ? */
3478
3479                 ret = btrfs_previous_item(chunk_root, path, 0,
3480                                           BTRFS_CHUNK_ITEM_KEY);
3481                 if (ret) {
3482                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3483                         ret = 0;
3484                         break;
3485                 }
3486
3487                 leaf = path->nodes[0];
3488                 slot = path->slots[0];
3489                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3490
3491                 if (found_key.objectid != key.objectid) {
3492                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3493                         break;
3494                 }
3495
3496                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3497                 chunk_type = btrfs_chunk_type(leaf, chunk);
3498
3499                 if (!counting) {
3500                         spin_lock(&fs_info->balance_lock);
3501                         bctl->stat.considered++;
3502                         spin_unlock(&fs_info->balance_lock);
3503                 }
3504
3505                 ret = should_balance_chunk(chunk_root, leaf, chunk,
3506                                            found_key.offset);
3507
3508                 btrfs_release_path(path);
3509                 if (!ret) {
3510                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3511                         goto loop;
3512                 }
3513
3514                 if (counting) {
3515                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3516                         spin_lock(&fs_info->balance_lock);
3517                         bctl->stat.expected++;
3518                         spin_unlock(&fs_info->balance_lock);
3519
3520                         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3521                                 count_data++;
3522                         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3523                                 count_sys++;
3524                         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3525                                 count_meta++;
3526
3527                         goto loop;
3528                 }
3529
3530                 /*
3531                  * Apply limit_min filter, no need to check if the LIMITS
3532                  * filter is used, limit_min is 0 by default
3533                  */
3534                 if (((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3535                                         count_data < bctl->data.limit_min)
3536                                 || ((chunk_type & BTRFS_BLOCK_GROUP_METADATA) &&
3537                                         count_meta < bctl->meta.limit_min)
3538                                 || ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&
3539                                         count_sys < bctl->sys.limit_min)) {
3540                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3541                         goto loop;
3542                 }
3543
3544                 ASSERT(fs_info->data_sinfo);
3545                 spin_lock(&fs_info->data_sinfo->lock);
3546                 bytes_used = fs_info->data_sinfo->bytes_used;
3547                 spin_unlock(&fs_info->data_sinfo->lock);
3548
3549                 if ((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3550                     !chunk_reserved && !bytes_used) {
3551                         trans = btrfs_start_transaction(chunk_root, 0);
3552                         if (IS_ERR(trans)) {
3553                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3554                                 ret = PTR_ERR(trans);
3555                                 goto error;
3556                         }
3557
3558                         ret = btrfs_force_chunk_alloc(trans, chunk_root,
3559                                                       BTRFS_BLOCK_GROUP_DATA);
3560                         btrfs_end_transaction(trans, chunk_root);
3561                         if (ret < 0) {
3562                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3563                                 goto error;
3564                         }
3565                         chunk_reserved = 1;
3566                 }
3567
3568                 ret = btrfs_relocate_chunk(chunk_root,
3569                                            found_key.offset);
3570                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3571                 if (ret && ret != -ENOSPC)
3572                         goto error;
3573                 if (ret == -ENOSPC) {
3574                         enospc_errors++;
3575                 } else {
3576                         spin_lock(&fs_info->balance_lock);
3577                         bctl->stat.completed++;
3578                         spin_unlock(&fs_info->balance_lock);
3579                 }
3580 loop:
3581                 if (found_key.offset == 0)
3582                         break;
3583                 key.offset = found_key.offset - 1;
3584         }
3585
3586         if (counting) {
3587                 btrfs_release_path(path);
3588                 counting = false;
3589                 goto again;
3590         }
3591 error:
3592         btrfs_free_path(path);
3593         if (enospc_errors) {
3594                 btrfs_info(fs_info, "%d enospc errors during balance",
3595                        enospc_errors);
3596                 if (!ret)
3597                         ret = -ENOSPC;
3598         }
3599
3600         return ret;
3601 }
3602
3603 /**
3604  * alloc_profile_is_valid - see if a given profile is valid and reduced
3605  * @flags: profile to validate
3606  * @extended: if true @flags is treated as an extended profile
3607  */
3608 static int alloc_profile_is_valid(u64 flags, int extended)
3609 {
3610         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3611                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3612
3613         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3614
3615         /* 1) check that all other bits are zeroed */
3616         if (flags & ~mask)
3617                 return 0;
3618
3619         /* 2) see if profile is reduced */
3620         if (flags == 0)
3621                 return !extended; /* "0" is valid for usual profiles */
3622
3623         /* true if exactly one bit set */
3624         return (flags & (flags - 1)) == 0;
3625 }
3626
3627 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3628 {
3629         /* cancel requested || normal exit path */
3630         return atomic_read(&fs_info->balance_cancel_req) ||
3631                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3632                  atomic_read(&fs_info->balance_cancel_req) == 0);
3633 }
3634
3635 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3636 {
3637         int ret;
3638
3639         unset_balance_control(fs_info);
3640         ret = del_balance_item(fs_info->tree_root);
3641         if (ret)
3642                 btrfs_std_error(fs_info, ret, NULL);
3643
3644         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3645 }
3646
3647 /* Non-zero return value signifies invalidity */
3648 static inline int validate_convert_profile(struct btrfs_balance_args *bctl_arg,
3649                 u64 allowed)
3650 {
3651         return ((bctl_arg->flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3652                 (!alloc_profile_is_valid(bctl_arg->target, 1) ||
3653                  (bctl_arg->target & ~allowed)));
3654 }
3655
3656 /*
3657  * Should be called with both balance and volume mutexes held
3658  */
3659 int btrfs_balance(struct btrfs_balance_control *bctl,
3660                   struct btrfs_ioctl_balance_args *bargs)
3661 {
3662         struct btrfs_fs_info *fs_info = bctl->fs_info;
3663         u64 allowed;
3664         int mixed = 0;
3665         int ret;
3666         u64 num_devices;
3667         unsigned seq;
3668
3669         if (btrfs_fs_closing(fs_info) ||
3670             atomic_read(&fs_info->balance_pause_req) ||
3671             atomic_read(&fs_info->balance_cancel_req)) {
3672                 ret = -EINVAL;
3673                 goto out;
3674         }
3675
3676         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3677         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3678                 mixed = 1;
3679
3680         /*
3681          * In case of mixed groups both data and meta should be picked,
3682          * and identical options should be given for both of them.
3683          */
3684         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3685         if (mixed && (bctl->flags & allowed)) {
3686                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3687                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3688                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3689                         btrfs_err(fs_info, "with mixed groups data and "
3690                                    "metadata balance options must be the same");
3691                         ret = -EINVAL;
3692                         goto out;
3693                 }
3694         }
3695
3696         num_devices = fs_info->fs_devices->num_devices;
3697         btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
3698         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3699                 BUG_ON(num_devices < 1);
3700                 num_devices--;
3701         }
3702         btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
3703         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE | BTRFS_BLOCK_GROUP_DUP;
3704         if (num_devices > 1)
3705                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3706         if (num_devices > 2)
3707                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3708         if (num_devices > 3)
3709                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3710                             BTRFS_BLOCK_GROUP_RAID6);
3711         if (validate_convert_profile(&bctl->data, allowed)) {
3712                 btrfs_err(fs_info, "unable to start balance with target "
3713                            "data profile %llu",
3714                        bctl->data.target);
3715                 ret = -EINVAL;
3716                 goto out;
3717         }
3718         if (validate_convert_profile(&bctl->meta, allowed)) {
3719                 btrfs_err(fs_info,
3720                            "unable to start balance with target metadata profile %llu",
3721                        bctl->meta.target);
3722                 ret = -EINVAL;
3723                 goto out;
3724         }
3725         if (validate_convert_profile(&bctl->sys, allowed)) {
3726                 btrfs_err(fs_info,
3727                            "unable to start balance with target system profile %llu",
3728                        bctl->sys.target);
3729                 ret = -EINVAL;
3730                 goto out;
3731         }
3732
3733         /* allow to reduce meta or sys integrity only if force set */
3734         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3735                         BTRFS_BLOCK_GROUP_RAID10 |
3736                         BTRFS_BLOCK_GROUP_RAID5 |
3737                         BTRFS_BLOCK_GROUP_RAID6;
3738         do {
3739                 seq = read_seqbegin(&fs_info->profiles_lock);
3740
3741                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3742                      (fs_info->avail_system_alloc_bits & allowed) &&
3743                      !(bctl->sys.target & allowed)) ||
3744                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3745                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3746                      !(bctl->meta.target & allowed))) {
3747                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3748                                 btrfs_info(fs_info, "force reducing metadata integrity");
3749                         } else {
3750                                 btrfs_err(fs_info, "balance will reduce metadata "
3751                                            "integrity, use force if you want this");
3752                                 ret = -EINVAL;
3753                                 goto out;
3754                         }
3755                 }
3756         } while (read_seqretry(&fs_info->profiles_lock, seq));
3757
3758         if (btrfs_get_num_tolerated_disk_barrier_failures(bctl->meta.target) <
3759                 btrfs_get_num_tolerated_disk_barrier_failures(bctl->data.target)) {
3760                 btrfs_warn(fs_info,
3761         "metadata profile 0x%llx has lower redundancy than data profile 0x%llx",
3762                         bctl->meta.target, bctl->data.target);
3763         }
3764
3765         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3766                 fs_info->num_tolerated_disk_barrier_failures = min(
3767                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info),
3768                         btrfs_get_num_tolerated_disk_barrier_failures(
3769                                 bctl->sys.target));
3770         }
3771
3772         ret = insert_balance_item(fs_info->tree_root, bctl);
3773         if (ret && ret != -EEXIST)
3774                 goto out;
3775
3776         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3777                 BUG_ON(ret == -EEXIST);
3778                 set_balance_control(bctl);
3779         } else {
3780                 BUG_ON(ret != -EEXIST);
3781                 spin_lock(&fs_info->balance_lock);
3782                 update_balance_args(bctl);
3783                 spin_unlock(&fs_info->balance_lock);
3784         }
3785
3786         atomic_inc(&fs_info->balance_running);
3787         mutex_unlock(&fs_info->balance_mutex);
3788
3789         ret = __btrfs_balance(fs_info);
3790
3791         mutex_lock(&fs_info->balance_mutex);
3792         atomic_dec(&fs_info->balance_running);
3793
3794         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3795                 fs_info->num_tolerated_disk_barrier_failures =
3796                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3797         }
3798
3799         if (bargs) {
3800                 memset(bargs, 0, sizeof(*bargs));
3801                 update_ioctl_balance_args(fs_info, 0, bargs);
3802         }
3803
3804         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3805             balance_need_close(fs_info)) {
3806                 __cancel_balance(fs_info);
3807         }
3808
3809         wake_up(&fs_info->balance_wait_q);
3810
3811         return ret;
3812 out:
3813         if (bctl->flags & BTRFS_BALANCE_RESUME)
3814                 __cancel_balance(fs_info);
3815         else {
3816                 kfree(bctl);
3817                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3818         }
3819         return ret;
3820 }
3821
3822 static int balance_kthread(void *data)
3823 {
3824         struct btrfs_fs_info *fs_info = data;
3825         int ret = 0;
3826
3827         mutex_lock(&fs_info->volume_mutex);
3828         mutex_lock(&fs_info->balance_mutex);
3829
3830         if (fs_info->balance_ctl) {
3831                 btrfs_info(fs_info, "continuing balance");
3832                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3833         }
3834
3835         mutex_unlock(&fs_info->balance_mutex);
3836         mutex_unlock(&fs_info->volume_mutex);
3837
3838         return ret;
3839 }
3840
3841 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3842 {
3843         struct task_struct *tsk;
3844
3845         spin_lock(&fs_info->balance_lock);
3846         if (!fs_info->balance_ctl) {
3847                 spin_unlock(&fs_info->balance_lock);
3848                 return 0;
3849         }
3850         spin_unlock(&fs_info->balance_lock);
3851
3852         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3853                 btrfs_info(fs_info, "force skipping balance");
3854                 return 0;
3855         }
3856
3857         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3858         return PTR_ERR_OR_ZERO(tsk);
3859 }
3860
3861 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3862 {
3863         struct btrfs_balance_control *bctl;
3864         struct btrfs_balance_item *item;
3865         struct btrfs_disk_balance_args disk_bargs;
3866         struct btrfs_path *path;
3867         struct extent_buffer *leaf;
3868         struct btrfs_key key;
3869         int ret;
3870
3871         path = btrfs_alloc_path();
3872         if (!path)
3873                 return -ENOMEM;
3874
3875         key.objectid = BTRFS_BALANCE_OBJECTID;
3876         key.type = BTRFS_TEMPORARY_ITEM_KEY;
3877         key.offset = 0;
3878
3879         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3880         if (ret < 0)
3881                 goto out;
3882         if (ret > 0) { /* ret = -ENOENT; */
3883                 ret = 0;
3884                 goto out;
3885         }
3886
3887         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3888         if (!bctl) {
3889                 ret = -ENOMEM;
3890                 goto out;
3891         }
3892
3893         leaf = path->nodes[0];
3894         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3895
3896         bctl->fs_info = fs_info;
3897         bctl->flags = btrfs_balance_flags(leaf, item);
3898         bctl->flags |= BTRFS_BALANCE_RESUME;
3899
3900         btrfs_balance_data(leaf, item, &disk_bargs);
3901         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3902         btrfs_balance_meta(leaf, item, &disk_bargs);
3903         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3904         btrfs_balance_sys(leaf, item, &disk_bargs);
3905         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3906
3907         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3908
3909         mutex_lock(&fs_info->volume_mutex);
3910         mutex_lock(&fs_info->balance_mutex);
3911
3912         set_balance_control(bctl);
3913
3914         mutex_unlock(&fs_info->balance_mutex);
3915         mutex_unlock(&fs_info->volume_mutex);
3916 out:
3917         btrfs_free_path(path);
3918         return ret;
3919 }
3920
3921 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3922 {
3923         int ret = 0;
3924
3925         mutex_lock(&fs_info->balance_mutex);
3926         if (!fs_info->balance_ctl) {
3927                 mutex_unlock(&fs_info->balance_mutex);
3928                 return -ENOTCONN;
3929         }
3930
3931         if (atomic_read(&fs_info->balance_running)) {
3932                 atomic_inc(&fs_info->balance_pause_req);
3933                 mutex_unlock(&fs_info->balance_mutex);
3934
3935                 wait_event(fs_info->balance_wait_q,
3936                            atomic_read(&fs_info->balance_running) == 0);
3937
3938                 mutex_lock(&fs_info->balance_mutex);
3939                 /* we are good with balance_ctl ripped off from under us */
3940                 BUG_ON(atomic_read(&fs_info->balance_running));
3941                 atomic_dec(&fs_info->balance_pause_req);
3942         } else {
3943                 ret = -ENOTCONN;
3944         }
3945
3946         mutex_unlock(&fs_info->balance_mutex);
3947         return ret;
3948 }
3949
3950 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3951 {
3952         if (fs_info->sb->s_flags & MS_RDONLY)
3953                 return -EROFS;
3954
3955         mutex_lock(&fs_info->balance_mutex);
3956         if (!fs_info->balance_ctl) {
3957                 mutex_unlock(&fs_info->balance_mutex);
3958                 return -ENOTCONN;
3959         }
3960
3961         atomic_inc(&fs_info->balance_cancel_req);
3962         /*
3963          * if we are running just wait and return, balance item is
3964          * deleted in btrfs_balance in this case
3965          */
3966         if (atomic_read(&fs_info->balance_running)) {
3967                 mutex_unlock(&fs_info->balance_mutex);
3968                 wait_event(fs_info->balance_wait_q,
3969                            atomic_read(&fs_info->balance_running) == 0);
3970                 mutex_lock(&fs_info->balance_mutex);
3971         } else {
3972                 /* __cancel_balance needs volume_mutex */
3973                 mutex_unlock(&fs_info->balance_mutex);
3974                 mutex_lock(&fs_info->volume_mutex);
3975                 mutex_lock(&fs_info->balance_mutex);
3976
3977                 if (fs_info->balance_ctl)
3978                         __cancel_balance(fs_info);
3979
3980                 mutex_unlock(&fs_info->volume_mutex);
3981         }
3982
3983         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3984         atomic_dec(&fs_info->balance_cancel_req);
3985         mutex_unlock(&fs_info->balance_mutex);
3986         return 0;
3987 }
3988
3989 static int btrfs_uuid_scan_kthread(void *data)
3990 {
3991         struct btrfs_fs_info *fs_info = data;
3992         struct btrfs_root *root = fs_info->tree_root;
3993         struct btrfs_key key;
3994         struct btrfs_key max_key;
3995         struct btrfs_path *path = NULL;
3996         int ret = 0;
3997         struct extent_buffer *eb;
3998         int slot;
3999         struct btrfs_root_item root_item;
4000         u32 item_size;
4001         struct btrfs_trans_handle *trans = NULL;
4002
4003         path = btrfs_alloc_path();
4004         if (!path) {
4005                 ret = -ENOMEM;
4006                 goto out;
4007         }
4008
4009         key.objectid = 0;
4010         key.type = BTRFS_ROOT_ITEM_KEY;
4011         key.offset = 0;
4012
4013         max_key.objectid = (u64)-1;
4014         max_key.type = BTRFS_ROOT_ITEM_KEY;
4015         max_key.offset = (u64)-1;
4016
4017         while (1) {
4018                 ret = btrfs_search_forward(root, &key, path, 0);
4019                 if (ret) {
4020                         if (ret > 0)
4021                                 ret = 0;
4022                         break;
4023                 }
4024
4025                 if (key.type != BTRFS_ROOT_ITEM_KEY ||
4026                     (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
4027                      key.objectid != BTRFS_FS_TREE_OBJECTID) ||
4028                     key.objectid > BTRFS_LAST_FREE_OBJECTID)
4029                         goto skip;
4030
4031                 eb = path->nodes[0];
4032                 slot = path->slots[0];
4033                 item_size = btrfs_item_size_nr(eb, slot);
4034                 if (item_size < sizeof(root_item))
4035                         goto skip;
4036
4037                 read_extent_buffer(eb, &root_item,
4038                                    btrfs_item_ptr_offset(eb, slot),
4039                                    (int)sizeof(root_item));
4040                 if (btrfs_root_refs(&root_item) == 0)
4041                         goto skip;
4042
4043                 if (!btrfs_is_empty_uuid(root_item.uuid) ||
4044                     !btrfs_is_empty_uuid(root_item.received_uuid)) {
4045                         if (trans)
4046                                 goto update_tree;
4047
4048                         btrfs_release_path(path);
4049                         /*
4050                          * 1 - subvol uuid item
4051                          * 1 - received_subvol uuid item
4052                          */
4053                         trans = btrfs_start_transaction(fs_info->uuid_root, 2);
4054                         if (IS_ERR(trans)) {
4055                                 ret = PTR_ERR(trans);
4056                                 break;
4057                         }
4058                         continue;
4059                 } else {
4060                         goto skip;
4061                 }
4062 update_tree:
4063                 if (!btrfs_is_empty_uuid(root_item.uuid)) {
4064                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4065                                                   root_item.uuid,
4066                                                   BTRFS_UUID_KEY_SUBVOL,
4067                                                   key.objectid);
4068                         if (ret < 0) {
4069                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4070                                         ret);
4071                                 break;
4072                         }
4073                 }
4074
4075                 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
4076                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4077                                                   root_item.received_uuid,
4078                                                  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4079                                                   key.objectid);
4080                         if (ret < 0) {
4081                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4082                                         ret);
4083                                 break;
4084                         }
4085                 }
4086
4087 skip:
4088                 if (trans) {
4089                         ret = btrfs_end_transaction(trans, fs_info->uuid_root);
4090                         trans = NULL;
4091                         if (ret)
4092                                 break;
4093                 }
4094
4095                 btrfs_release_path(path);
4096                 if (key.offset < (u64)-1) {
4097                         key.offset++;
4098                 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
4099                         key.offset = 0;
4100                         key.type = BTRFS_ROOT_ITEM_KEY;
4101                 } else if (key.objectid < (u64)-1) {
4102                         key.offset = 0;
4103                         key.type = BTRFS_ROOT_ITEM_KEY;
4104                         key.objectid++;
4105                 } else {
4106                         break;
4107                 }
4108                 cond_resched();
4109         }
4110
4111 out:
4112         btrfs_free_path(path);
4113         if (trans && !IS_ERR(trans))
4114                 btrfs_end_transaction(trans, fs_info->uuid_root);
4115         if (ret)
4116                 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
4117         else
4118                 fs_info->update_uuid_tree_gen = 1;
4119         up(&fs_info->uuid_tree_rescan_sem);
4120         return 0;
4121 }
4122
4123 /*
4124  * Callback for btrfs_uuid_tree_iterate().
4125  * returns:
4126  * 0    check succeeded, the entry is not outdated.
4127  * < 0  if an error occurred.
4128  * > 0  if the check failed, which means the caller shall remove the entry.
4129  */
4130 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
4131                                        u8 *uuid, u8 type, u64 subid)
4132 {
4133         struct btrfs_key key;
4134         int ret = 0;
4135         struct btrfs_root *subvol_root;
4136
4137         if (type != BTRFS_UUID_KEY_SUBVOL &&
4138             type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
4139                 goto out;
4140
4141         key.objectid = subid;
4142         key.type = BTRFS_ROOT_ITEM_KEY;
4143         key.offset = (u64)-1;
4144         subvol_root = btrfs_read_fs_root_no_name(fs_info, &key);
4145         if (IS_ERR(subvol_root)) {
4146                 ret = PTR_ERR(subvol_root);
4147                 if (ret == -ENOENT)
4148                         ret = 1;
4149                 goto out;
4150         }
4151
4152         switch (type) {
4153         case BTRFS_UUID_KEY_SUBVOL:
4154                 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
4155                         ret = 1;
4156                 break;
4157         case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
4158                 if (memcmp(uuid, subvol_root->root_item.received_uuid,
4159                            BTRFS_UUID_SIZE))
4160                         ret = 1;
4161                 break;
4162         }
4163
4164 out:
4165         return ret;
4166 }
4167
4168 static int btrfs_uuid_rescan_kthread(void *data)
4169 {
4170         struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
4171         int ret;
4172
4173         /*
4174          * 1st step is to iterate through the existing UUID tree and
4175          * to delete all entries that contain outdated data.
4176          * 2nd step is to add all missing entries to the UUID tree.
4177          */
4178         ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
4179         if (ret < 0) {
4180                 btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
4181                 up(&fs_info->uuid_tree_rescan_sem);
4182                 return ret;
4183         }
4184         return btrfs_uuid_scan_kthread(data);
4185 }
4186
4187 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
4188 {
4189         struct btrfs_trans_handle *trans;
4190         struct btrfs_root *tree_root = fs_info->tree_root;
4191         struct btrfs_root *uuid_root;
4192         struct task_struct *task;
4193         int ret;
4194
4195         /*
4196          * 1 - root node
4197          * 1 - root item
4198          */
4199         trans = btrfs_start_transaction(tree_root, 2);
4200         if (IS_ERR(trans))
4201                 return PTR_ERR(trans);
4202
4203         uuid_root = btrfs_create_tree(trans, fs_info,
4204                                       BTRFS_UUID_TREE_OBJECTID);
4205         if (IS_ERR(uuid_root)) {
4206                 ret = PTR_ERR(uuid_root);
4207                 btrfs_abort_transaction(trans, tree_root, ret);
4208                 return ret;
4209         }
4210
4211         fs_info->uuid_root = uuid_root;
4212
4213         ret = btrfs_commit_transaction(trans, tree_root);
4214         if (ret)
4215                 return ret;
4216
4217         down(&fs_info->uuid_tree_rescan_sem);
4218         task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
4219         if (IS_ERR(task)) {
4220                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4221                 btrfs_warn(fs_info, "failed to start uuid_scan task");
4222                 up(&fs_info->uuid_tree_rescan_sem);
4223                 return PTR_ERR(task);
4224         }
4225
4226         return 0;
4227 }
4228
4229 int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
4230 {
4231         struct task_struct *task;
4232
4233         down(&fs_info->uuid_tree_rescan_sem);
4234         task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
4235         if (IS_ERR(task)) {
4236                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4237                 btrfs_warn(fs_info, "failed to start uuid_rescan task");
4238                 up(&fs_info->uuid_tree_rescan_sem);
4239                 return PTR_ERR(task);
4240         }
4241
4242         return 0;
4243 }
4244
4245 /*
4246  * shrinking a device means finding all of the device extents past
4247  * the new size, and then following the back refs to the chunks.
4248  * The chunk relocation code actually frees the device extent
4249  */
4250 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
4251 {
4252         struct btrfs_trans_handle *trans;
4253         struct btrfs_root *root = device->dev_root;
4254         struct btrfs_dev_extent *dev_extent = NULL;
4255         struct btrfs_path *path;
4256         u64 length;
4257         u64 chunk_offset;
4258         int ret;
4259         int slot;
4260         int failed = 0;
4261         bool retried = false;
4262         bool checked_pending_chunks = false;
4263         struct extent_buffer *l;
4264         struct btrfs_key key;
4265         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4266         u64 old_total = btrfs_super_total_bytes(super_copy);
4267         u64 old_size = btrfs_device_get_total_bytes(device);
4268         u64 diff = old_size - new_size;
4269
4270         if (device->is_tgtdev_for_dev_replace)
4271                 return -EINVAL;
4272
4273         path = btrfs_alloc_path();
4274         if (!path)
4275                 return -ENOMEM;
4276
4277         path->reada = READA_FORWARD;
4278
4279         lock_chunks(root);
4280
4281         btrfs_device_set_total_bytes(device, new_size);
4282         if (device->writeable) {
4283                 device->fs_devices->total_rw_bytes -= diff;
4284                 spin_lock(&root->fs_info->free_chunk_lock);
4285                 root->fs_info->free_chunk_space -= diff;
4286                 spin_unlock(&root->fs_info->free_chunk_lock);
4287         }
4288         unlock_chunks(root);
4289
4290 again:
4291         key.objectid = device->devid;
4292         key.offset = (u64)-1;
4293         key.type = BTRFS_DEV_EXTENT_KEY;
4294
4295         do {
4296                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
4297                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4298                 if (ret < 0) {
4299                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4300                         goto done;
4301                 }
4302
4303                 ret = btrfs_previous_item(root, path, 0, key.type);
4304                 if (ret)
4305                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4306                 if (ret < 0)
4307                         goto done;
4308                 if (ret) {
4309                         ret = 0;
4310                         btrfs_release_path(path);
4311                         break;
4312                 }
4313
4314                 l = path->nodes[0];
4315                 slot = path->slots[0];
4316                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
4317
4318                 if (key.objectid != device->devid) {
4319                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4320                         btrfs_release_path(path);
4321                         break;
4322                 }
4323
4324                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
4325                 length = btrfs_dev_extent_length(l, dev_extent);
4326
4327                 if (key.offset + length <= new_size) {
4328                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4329                         btrfs_release_path(path);
4330                         break;
4331                 }
4332
4333                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
4334                 btrfs_release_path(path);
4335
4336                 ret = btrfs_relocate_chunk(root, chunk_offset);
4337                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4338                 if (ret && ret != -ENOSPC)
4339                         goto done;
4340                 if (ret == -ENOSPC)
4341                         failed++;
4342         } while (key.offset-- > 0);
4343
4344         if (failed && !retried) {
4345                 failed = 0;
4346                 retried = true;
4347                 goto again;
4348         } else if (failed && retried) {
4349                 ret = -ENOSPC;
4350                 goto done;
4351         }
4352
4353         /* Shrinking succeeded, else we would be at "done". */
4354         trans = btrfs_start_transaction(root, 0);
4355         if (IS_ERR(trans)) {
4356                 ret = PTR_ERR(trans);
4357                 goto done;
4358         }
4359
4360         lock_chunks(root);
4361
4362         /*
4363          * We checked in the above loop all device extents that were already in
4364          * the device tree. However before we have updated the device's
4365          * total_bytes to the new size, we might have had chunk allocations that
4366          * have not complete yet (new block groups attached to transaction
4367          * handles), and therefore their device extents were not yet in the
4368          * device tree and we missed them in the loop above. So if we have any
4369          * pending chunk using a device extent that overlaps the device range
4370          * that we can not use anymore, commit the current transaction and
4371          * repeat the search on the device tree - this way we guarantee we will
4372          * not have chunks using device extents that end beyond 'new_size'.
4373          */
4374         if (!checked_pending_chunks) {
4375                 u64 start = new_size;
4376                 u64 len = old_size - new_size;
4377
4378                 if (contains_pending_extent(trans->transaction, device,
4379                                             &start, len)) {
4380                         unlock_chunks(root);
4381                         checked_pending_chunks = true;
4382                         failed = 0;
4383                         retried = false;
4384                         ret = btrfs_commit_transaction(trans, root);
4385                         if (ret)
4386                                 goto done;
4387                         goto again;
4388                 }
4389         }
4390
4391         btrfs_device_set_disk_total_bytes(device, new_size);
4392         if (list_empty(&device->resized_list))
4393                 list_add_tail(&device->resized_list,
4394                               &root->fs_info->fs_devices->resized_devices);
4395
4396         WARN_ON(diff > old_total);
4397         btrfs_set_super_total_bytes(super_copy, old_total - diff);
4398         unlock_chunks(root);
4399
4400         /* Now btrfs_update_device() will change the on-disk size. */
4401         ret = btrfs_update_device(trans, device);
4402         btrfs_end_transaction(trans, root);
4403 done:
4404         btrfs_free_path(path);
4405         if (ret) {
4406                 lock_chunks(root);
4407                 btrfs_device_set_total_bytes(device, old_size);
4408                 if (device->writeable)
4409                         device->fs_devices->total_rw_bytes += diff;
4410                 spin_lock(&root->fs_info->free_chunk_lock);
4411                 root->fs_info->free_chunk_space += diff;
4412                 spin_unlock(&root->fs_info->free_chunk_lock);
4413                 unlock_chunks(root);
4414         }
4415         return ret;
4416 }
4417
4418 static int btrfs_add_system_chunk(struct btrfs_root *root,
4419                            struct btrfs_key *key,
4420                            struct btrfs_chunk *chunk, int item_size)
4421 {
4422         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4423         struct btrfs_disk_key disk_key;
4424         u32 array_size;
4425         u8 *ptr;
4426
4427         lock_chunks(root);
4428         array_size = btrfs_super_sys_array_size(super_copy);
4429         if (array_size + item_size + sizeof(disk_key)
4430                         > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
4431                 unlock_chunks(root);
4432                 return -EFBIG;
4433         }
4434
4435         ptr = super_copy->sys_chunk_array + array_size;
4436         btrfs_cpu_key_to_disk(&disk_key, key);
4437         memcpy(ptr, &disk_key, sizeof(disk_key));
4438         ptr += sizeof(disk_key);
4439         memcpy(ptr, chunk, item_size);
4440         item_size += sizeof(disk_key);
4441         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
4442         unlock_chunks(root);
4443
4444         return 0;
4445 }
4446
4447 /*
4448  * sort the devices in descending order by max_avail, total_avail
4449  */
4450 static int btrfs_cmp_device_info(const void *a, const void *b)
4451 {
4452         const struct btrfs_device_info *di_a = a;
4453         const struct btrfs_device_info *di_b = b;
4454
4455         if (di_a->max_avail > di_b->max_avail)
4456                 return -1;
4457         if (di_a->max_avail < di_b->max_avail)
4458                 return 1;
4459         if (di_a->total_avail > di_b->total_avail)
4460                 return -1;
4461         if (di_a->total_avail < di_b->total_avail)
4462                 return 1;
4463         return 0;
4464 }
4465
4466 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
4467 {
4468         /* TODO allow them to set a preferred stripe size */
4469         return SZ_64K;
4470 }
4471
4472 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
4473 {
4474         if (!(type & BTRFS_BLOCK_GROUP_RAID56_MASK))
4475                 return;
4476
4477         btrfs_set_fs_incompat(info, RAID56);
4478 }
4479
4480 #define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)             \
4481                         - sizeof(struct btrfs_item)             \
4482                         - sizeof(struct btrfs_chunk))           \
4483                         / sizeof(struct btrfs_stripe) + 1)
4484
4485 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
4486                                 - 2 * sizeof(struct btrfs_disk_key)     \
4487                                 - 2 * sizeof(struct btrfs_chunk))       \
4488                                 / sizeof(struct btrfs_stripe) + 1)
4489
4490 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4491                                struct btrfs_root *extent_root, u64 start,
4492                                u64 type)
4493 {
4494         struct btrfs_fs_info *info = extent_root->fs_info;
4495         struct btrfs_fs_devices *fs_devices = info->fs_devices;
4496         struct list_head *cur;
4497         struct map_lookup *map = NULL;
4498         struct extent_map_tree *em_tree;
4499         struct extent_map *em;
4500         struct btrfs_device_info *devices_info = NULL;
4501         u64 total_avail;
4502         int num_stripes;        /* total number of stripes to allocate */
4503         int data_stripes;       /* number of stripes that count for
4504                                    block group size */
4505         int sub_stripes;        /* sub_stripes info for map */
4506         int dev_stripes;        /* stripes per dev */
4507         int devs_max;           /* max devs to use */
4508         int devs_min;           /* min devs needed */
4509         int devs_increment;     /* ndevs has to be a multiple of this */
4510         int ncopies;            /* how many copies to data has */
4511         int ret;
4512         u64 max_stripe_size;
4513         u64 max_chunk_size;
4514         u64 stripe_size;
4515         u64 num_bytes;
4516         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
4517         int ndevs;
4518         int i;
4519         int j;
4520         int index;
4521
4522         BUG_ON(!alloc_profile_is_valid(type, 0));
4523
4524         if (list_empty(&fs_devices->alloc_list))
4525                 return -ENOSPC;
4526
4527         index = __get_raid_index(type);
4528
4529         sub_stripes = btrfs_raid_array[index].sub_stripes;
4530         dev_stripes = btrfs_raid_array[index].dev_stripes;
4531         devs_max = btrfs_raid_array[index].devs_max;
4532         devs_min = btrfs_raid_array[index].devs_min;
4533         devs_increment = btrfs_raid_array[index].devs_increment;
4534         ncopies = btrfs_raid_array[index].ncopies;
4535
4536         if (type & BTRFS_BLOCK_GROUP_DATA) {
4537                 max_stripe_size = SZ_1G;
4538                 max_chunk_size = 10 * max_stripe_size;
4539                 if (!devs_max)
4540                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4541         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
4542                 /* for larger filesystems, use larger metadata chunks */
4543                 if (fs_devices->total_rw_bytes > 50ULL * SZ_1G)
4544                         max_stripe_size = SZ_1G;
4545                 else
4546                         max_stripe_size = SZ_256M;
4547                 max_chunk_size = max_stripe_size;
4548                 if (!devs_max)
4549                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4550         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
4551                 max_stripe_size = SZ_32M;
4552                 max_chunk_size = 2 * max_stripe_size;
4553                 if (!devs_max)
4554                         devs_max = BTRFS_MAX_DEVS_SYS_CHUNK;
4555         } else {
4556                 btrfs_err(info, "invalid chunk type 0x%llx requested",
4557                        type);
4558                 BUG_ON(1);
4559         }
4560
4561         /* we don't want a chunk larger than 10% of writeable space */
4562         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
4563                              max_chunk_size);
4564
4565         devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
4566                                GFP_NOFS);
4567         if (!devices_info)
4568                 return -ENOMEM;
4569
4570         cur = fs_devices->alloc_list.next;
4571
4572         /*
4573          * in the first pass through the devices list, we gather information
4574          * about the available holes on each device.
4575          */
4576         ndevs = 0;
4577         while (cur != &fs_devices->alloc_list) {
4578                 struct btrfs_device *device;
4579                 u64 max_avail;
4580                 u64 dev_offset;
4581
4582                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
4583
4584                 cur = cur->next;
4585
4586                 if (!device->writeable) {
4587                         WARN(1, KERN_ERR
4588                                "BTRFS: read-only device in alloc_list\n");
4589                         continue;
4590                 }
4591
4592                 if (!device->in_fs_metadata ||
4593                     device->is_tgtdev_for_dev_replace)
4594                         continue;
4595
4596                 if (device->total_bytes > device->bytes_used)
4597                         total_avail = device->total_bytes - device->bytes_used;
4598                 else
4599                         total_avail = 0;
4600
4601                 /* If there is no space on this device, skip it. */
4602                 if (total_avail == 0)
4603                         continue;
4604
4605                 ret = find_free_dev_extent(trans, device,
4606                                            max_stripe_size * dev_stripes,
4607                                            &dev_offset, &max_avail);
4608                 if (ret && ret != -ENOSPC)
4609                         goto error;
4610
4611                 if (ret == 0)
4612                         max_avail = max_stripe_size * dev_stripes;
4613
4614                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
4615                         continue;
4616
4617                 if (ndevs == fs_devices->rw_devices) {
4618                         WARN(1, "%s: found more than %llu devices\n",
4619                              __func__, fs_devices->rw_devices);
4620                         break;
4621                 }
4622                 devices_info[ndevs].dev_offset = dev_offset;
4623                 devices_info[ndevs].max_avail = max_avail;
4624                 devices_info[ndevs].total_avail = total_avail;
4625                 devices_info[ndevs].dev = device;
4626                 ++ndevs;
4627         }
4628
4629         /*
4630          * now sort the devices by hole size / available space
4631          */
4632         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
4633              btrfs_cmp_device_info, NULL);
4634
4635         /* round down to number of usable stripes */
4636         ndevs -= ndevs % devs_increment;
4637
4638         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
4639                 ret = -ENOSPC;
4640                 goto error;
4641         }
4642
4643         if (devs_max && ndevs > devs_max)
4644                 ndevs = devs_max;
4645         /*
4646          * the primary goal is to maximize the number of stripes, so use as many
4647          * devices as possible, even if the stripes are not maximum sized.
4648          */
4649         stripe_size = devices_info[ndevs-1].max_avail;
4650         num_stripes = ndevs * dev_stripes;
4651
4652         /*
4653          * this will have to be fixed for RAID1 and RAID10 over
4654          * more drives
4655          */
4656         data_stripes = num_stripes / ncopies;
4657
4658         if (type & BTRFS_BLOCK_GROUP_RAID5) {
4659                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
4660                                  btrfs_super_stripesize(info->super_copy));
4661                 data_stripes = num_stripes - 1;
4662         }
4663         if (type & BTRFS_BLOCK_GROUP_RAID6) {
4664                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
4665                                  btrfs_super_stripesize(info->super_copy));
4666                 data_stripes = num_stripes - 2;
4667         }
4668
4669         /*
4670          * Use the number of data stripes to figure out how big this chunk
4671          * is really going to be in terms of logical address space,
4672          * and compare that answer with the max chunk size
4673          */
4674         if (stripe_size * data_stripes > max_chunk_size) {
4675                 u64 mask = (1ULL << 24) - 1;
4676
4677                 stripe_size = div_u64(max_chunk_size, data_stripes);
4678
4679                 /* bump the answer up to a 16MB boundary */
4680                 stripe_size = (stripe_size + mask) & ~mask;
4681
4682                 /* but don't go higher than the limits we found
4683                  * while searching for free extents
4684                  */
4685                 if (stripe_size > devices_info[ndevs-1].max_avail)
4686                         stripe_size = devices_info[ndevs-1].max_avail;
4687         }
4688
4689         stripe_size = div_u64(stripe_size, dev_stripes);
4690
4691         /* align to BTRFS_STRIPE_LEN */
4692         stripe_size = div_u64(stripe_size, raid_stripe_len);
4693         stripe_size *= raid_stripe_len;
4694
4695         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4696         if (!map) {
4697                 ret = -ENOMEM;
4698                 goto error;
4699         }
4700         map->num_stripes = num_stripes;
4701
4702         for (i = 0; i < ndevs; ++i) {
4703                 for (j = 0; j < dev_stripes; ++j) {
4704                         int s = i * dev_stripes + j;
4705                         map->stripes[s].dev = devices_info[i].dev;
4706                         map->stripes[s].physical = devices_info[i].dev_offset +
4707                                                    j * stripe_size;
4708                 }
4709         }
4710         map->sector_size = extent_root->sectorsize;
4711         map->stripe_len = raid_stripe_len;
4712         map->io_align = raid_stripe_len;
4713         map->io_width = raid_stripe_len;
4714         map->type = type;
4715         map->sub_stripes = sub_stripes;
4716
4717         num_bytes = stripe_size * data_stripes;
4718
4719         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
4720
4721         em = alloc_extent_map();
4722         if (!em) {
4723                 kfree(map);
4724                 ret = -ENOMEM;
4725                 goto error;
4726         }
4727         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
4728         em->map_lookup = map;
4729         em->start = start;
4730         em->len = num_bytes;
4731         em->block_start = 0;
4732         em->block_len = em->len;
4733         em->orig_block_len = stripe_size;
4734
4735         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4736         write_lock(&em_tree->lock);
4737         ret = add_extent_mapping(em_tree, em, 0);
4738         if (!ret) {
4739                 list_add_tail(&em->list, &trans->transaction->pending_chunks);
4740                 atomic_inc(&em->refs);
4741         }
4742         write_unlock(&em_tree->lock);
4743         if (ret) {
4744                 free_extent_map(em);
4745                 goto error;
4746         }
4747
4748         ret = btrfs_make_block_group(trans, extent_root, 0, type,
4749                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4750                                      start, num_bytes);
4751         if (ret)
4752                 goto error_del_extent;
4753
4754         for (i = 0; i < map->num_stripes; i++) {
4755                 num_bytes = map->stripes[i].dev->bytes_used + stripe_size;
4756                 btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
4757         }
4758
4759         spin_lock(&extent_root->fs_info->free_chunk_lock);
4760         extent_root->fs_info->free_chunk_space -= (stripe_size *
4761                                                    map->num_stripes);
4762         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4763
4764         free_extent_map(em);
4765         check_raid56_incompat_flag(extent_root->fs_info, type);
4766
4767         kfree(devices_info);
4768         return 0;
4769
4770 error_del_extent:
4771         write_lock(&em_tree->lock);
4772         remove_extent_mapping(em_tree, em);
4773         write_unlock(&em_tree->lock);
4774
4775         /* One for our allocation */
4776         free_extent_map(em);
4777         /* One for the tree reference */
4778         free_extent_map(em);
4779         /* One for the pending_chunks list reference */
4780         free_extent_map(em);
4781 error:
4782         kfree(devices_info);
4783         return ret;
4784 }
4785
4786 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
4787                                 struct btrfs_root *extent_root,
4788                                 u64 chunk_offset, u64 chunk_size)
4789 {
4790         struct btrfs_key key;
4791         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4792         struct btrfs_device *device;
4793         struct btrfs_chunk *chunk;
4794         struct btrfs_stripe *stripe;
4795         struct extent_map_tree *em_tree;
4796         struct extent_map *em;
4797         struct map_lookup *map;
4798         size_t item_size;
4799         u64 dev_offset;
4800         u64 stripe_size;
4801         int i = 0;
4802         int ret = 0;
4803
4804         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4805         read_lock(&em_tree->lock);
4806         em = lookup_extent_mapping(em_tree, chunk_offset, chunk_size);
4807         read_unlock(&em_tree->lock);
4808
4809         if (!em) {
4810                 btrfs_crit(extent_root->fs_info, "unable to find logical "
4811                            "%Lu len %Lu", chunk_offset, chunk_size);
4812                 return -EINVAL;
4813         }
4814
4815         if (em->start != chunk_offset || em->len != chunk_size) {
4816                 btrfs_crit(extent_root->fs_info, "found a bad mapping, wanted"
4817                           " %Lu-%Lu, found %Lu-%Lu", chunk_offset,
4818                           chunk_size, em->start, em->len);
4819                 free_extent_map(em);
4820                 return -EINVAL;
4821         }
4822
4823         map = em->map_lookup;
4824         item_size = btrfs_chunk_item_size(map->num_stripes);
4825         stripe_size = em->orig_block_len;
4826
4827         chunk = kzalloc(item_size, GFP_NOFS);
4828         if (!chunk) {
4829                 ret = -ENOMEM;
4830                 goto out;
4831         }
4832
4833         /*
4834          * Take the device list mutex to prevent races with the final phase of
4835          * a device replace operation that replaces the device object associated
4836          * with the map's stripes, because the device object's id can change
4837          * at any time during that final phase of the device replace operation
4838          * (dev-replace.c:btrfs_dev_replace_finishing()).
4839          */
4840         mutex_lock(&chunk_root->fs_info->fs_devices->device_list_mutex);
4841         for (i = 0; i < map->num_stripes; i++) {
4842                 device = map->stripes[i].dev;
4843                 dev_offset = map->stripes[i].physical;
4844
4845                 ret = btrfs_update_device(trans, device);
4846                 if (ret)
4847                         break;
4848                 ret = btrfs_alloc_dev_extent(trans, device,
4849                                              chunk_root->root_key.objectid,
4850                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4851                                              chunk_offset, dev_offset,
4852                                              stripe_size);
4853                 if (ret)
4854                         break;
4855         }
4856         if (ret) {
4857                 mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
4858                 goto out;
4859         }
4860
4861         stripe = &chunk->stripe;
4862         for (i = 0; i < map->num_stripes; i++) {
4863                 device = map->stripes[i].dev;
4864                 dev_offset = map->stripes[i].physical;
4865
4866                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4867                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4868                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4869                 stripe++;
4870         }
4871         mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
4872
4873         btrfs_set_stack_chunk_length(chunk, chunk_size);
4874         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4875         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4876         btrfs_set_stack_chunk_type(chunk, map->type);
4877         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4878         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4879         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4880         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4881         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4882
4883         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4884         key.type = BTRFS_CHUNK_ITEM_KEY;
4885         key.offset = chunk_offset;
4886
4887         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4888         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4889                 /*
4890                  * TODO: Cleanup of inserted chunk root in case of
4891                  * failure.
4892                  */
4893                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4894                                              item_size);
4895         }
4896
4897 out:
4898         kfree(chunk);
4899         free_extent_map(em);
4900         return ret;
4901 }
4902
4903 /*
4904  * Chunk allocation falls into two parts. The first part does works
4905  * that make the new allocated chunk useable, but not do any operation
4906  * that modifies the chunk tree. The second part does the works that
4907  * require modifying the chunk tree. This division is important for the
4908  * bootstrap process of adding storage to a seed btrfs.
4909  */
4910 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4911                       struct btrfs_root *extent_root, u64 type)
4912 {
4913         u64 chunk_offset;
4914
4915         ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex));
4916         chunk_offset = find_next_chunk(extent_root->fs_info);
4917         return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
4918 }
4919
4920 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4921                                          struct btrfs_root *root,
4922                                          struct btrfs_device *device)
4923 {
4924         u64 chunk_offset;
4925         u64 sys_chunk_offset;
4926         u64 alloc_profile;
4927         struct btrfs_fs_info *fs_info = root->fs_info;
4928         struct btrfs_root *extent_root = fs_info->extent_root;
4929         int ret;
4930
4931         chunk_offset = find_next_chunk(fs_info);
4932         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4933         ret = __btrfs_alloc_chunk(trans, extent_root, chunk_offset,
4934                                   alloc_profile);
4935         if (ret)
4936                 return ret;
4937
4938         sys_chunk_offset = find_next_chunk(root->fs_info);
4939         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4940         ret = __btrfs_alloc_chunk(trans, extent_root, sys_chunk_offset,
4941                                   alloc_profile);
4942         return ret;
4943 }
4944
4945 static inline int btrfs_chunk_max_errors(struct map_lookup *map)
4946 {
4947         int max_errors;
4948
4949         if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4950                          BTRFS_BLOCK_GROUP_RAID10 |
4951                          BTRFS_BLOCK_GROUP_RAID5 |
4952                          BTRFS_BLOCK_GROUP_DUP)) {
4953                 max_errors = 1;
4954         } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
4955                 max_errors = 2;
4956         } else {
4957                 max_errors = 0;
4958         }
4959
4960         return max_errors;
4961 }
4962
4963 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4964 {
4965         struct extent_map *em;
4966         struct map_lookup *map;
4967         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4968         int readonly = 0;
4969         int miss_ndevs = 0;
4970         int i;
4971
4972         read_lock(&map_tree->map_tree.lock);
4973         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4974         read_unlock(&map_tree->map_tree.lock);
4975         if (!em)
4976                 return 1;
4977
4978         map = em->map_lookup;
4979         for (i = 0; i < map->num_stripes; i++) {
4980                 if (map->stripes[i].dev->missing) {
4981                         miss_ndevs++;
4982                         continue;
4983                 }
4984
4985                 if (!map->stripes[i].dev->writeable) {
4986                         readonly = 1;
4987                         goto end;
4988                 }
4989         }
4990
4991         /*
4992          * If the number of missing devices is larger than max errors,
4993          * we can not write the data into that chunk successfully, so
4994          * set it readonly.
4995          */
4996         if (miss_ndevs > btrfs_chunk_max_errors(map))
4997                 readonly = 1;
4998 end:
4999         free_extent_map(em);
5000         return readonly;
5001 }
5002
5003 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
5004 {
5005         extent_map_tree_init(&tree->map_tree);
5006 }
5007
5008 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
5009 {
5010         struct extent_map *em;
5011
5012         while (1) {
5013                 write_lock(&tree->map_tree.lock);
5014                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
5015                 if (em)
5016                         remove_extent_mapping(&tree->map_tree, em);
5017                 write_unlock(&tree->map_tree.lock);
5018                 if (!em)
5019                         break;
5020                 /* once for us */
5021                 free_extent_map(em);
5022                 /* once for the tree */
5023                 free_extent_map(em);
5024         }
5025 }
5026
5027 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
5028 {
5029         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5030         struct extent_map *em;
5031         struct map_lookup *map;
5032         struct extent_map_tree *em_tree = &map_tree->map_tree;
5033         int ret;
5034
5035         read_lock(&em_tree->lock);
5036         em = lookup_extent_mapping(em_tree, logical, len);
5037         read_unlock(&em_tree->lock);
5038
5039         /*
5040          * We could return errors for these cases, but that could get ugly and
5041          * we'd probably do the same thing which is just not do anything else
5042          * and exit, so return 1 so the callers don't try to use other copies.
5043          */
5044         if (!em) {
5045                 btrfs_crit(fs_info, "No mapping for %Lu-%Lu", logical,
5046                             logical+len);
5047                 return 1;
5048         }
5049
5050         if (em->start > logical || em->start + em->len < logical) {
5051                 btrfs_crit(fs_info, "Invalid mapping for %Lu-%Lu, got "
5052                             "%Lu-%Lu", logical, logical+len, em->start,
5053                             em->start + em->len);
5054                 free_extent_map(em);
5055                 return 1;
5056         }
5057
5058         map = em->map_lookup;
5059         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
5060                 ret = map->num_stripes;
5061         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5062                 ret = map->sub_stripes;
5063         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
5064                 ret = 2;
5065         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5066                 ret = 3;
5067         else
5068                 ret = 1;
5069         free_extent_map(em);
5070
5071         btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
5072         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
5073                 ret++;
5074         btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
5075
5076         return ret;
5077 }
5078
5079 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
5080                                     struct btrfs_mapping_tree *map_tree,
5081                                     u64 logical)
5082 {
5083         struct extent_map *em;
5084         struct map_lookup *map;
5085         struct extent_map_tree *em_tree = &map_tree->map_tree;
5086         unsigned long len = root->sectorsize;
5087
5088         read_lock(&em_tree->lock);
5089         em = lookup_extent_mapping(em_tree, logical, len);
5090         read_unlock(&em_tree->lock);
5091         BUG_ON(!em);
5092
5093         BUG_ON(em->start > logical || em->start + em->len < logical);
5094         map = em->map_lookup;
5095         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5096                 len = map->stripe_len * nr_data_stripes(map);
5097         free_extent_map(em);
5098         return len;
5099 }
5100
5101 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
5102                            u64 logical, u64 len, int mirror_num)
5103 {
5104         struct extent_map *em;
5105         struct map_lookup *map;
5106         struct extent_map_tree *em_tree = &map_tree->map_tree;
5107         int ret = 0;
5108
5109         read_lock(&em_tree->lock);
5110         em = lookup_extent_mapping(em_tree, logical, len);
5111         read_unlock(&em_tree->lock);
5112         BUG_ON(!em);
5113
5114         BUG_ON(em->start > logical || em->start + em->len < logical);
5115         map = em->map_lookup;
5116         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5117                 ret = 1;
5118         free_extent_map(em);
5119         return ret;
5120 }
5121
5122 static int find_live_mirror(struct btrfs_fs_info *fs_info,
5123                             struct map_lookup *map, int first, int num,
5124                             int optimal, int dev_replace_is_ongoing)
5125 {
5126         int i;
5127         int tolerance;
5128         struct btrfs_device *srcdev;
5129
5130         if (dev_replace_is_ongoing &&
5131             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
5132              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
5133                 srcdev = fs_info->dev_replace.srcdev;
5134         else
5135                 srcdev = NULL;
5136
5137         /*
5138          * try to avoid the drive that is the source drive for a
5139          * dev-replace procedure, only choose it if no other non-missing
5140          * mirror is available
5141          */
5142         for (tolerance = 0; tolerance < 2; tolerance++) {
5143                 if (map->stripes[optimal].dev->bdev &&
5144                     (tolerance || map->stripes[optimal].dev != srcdev))
5145                         return optimal;
5146                 for (i = first; i < first + num; i++) {
5147                         if (map->stripes[i].dev->bdev &&
5148                             (tolerance || map->stripes[i].dev != srcdev))
5149                                 return i;
5150                 }
5151         }
5152
5153         /* we couldn't find one that doesn't fail.  Just return something
5154          * and the io error handling code will clean up eventually
5155          */
5156         return optimal;
5157 }
5158
5159 static inline int parity_smaller(u64 a, u64 b)
5160 {
5161         return a > b;
5162 }
5163
5164 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
5165 static void sort_parity_stripes(struct btrfs_bio *bbio, int num_stripes)
5166 {
5167         struct btrfs_bio_stripe s;
5168         int i;
5169         u64 l;
5170         int again = 1;
5171
5172         while (again) {
5173                 again = 0;
5174                 for (i = 0; i < num_stripes - 1; i++) {
5175                         if (parity_smaller(bbio->raid_map[i],
5176                                            bbio->raid_map[i+1])) {
5177                                 s = bbio->stripes[i];
5178                                 l = bbio->raid_map[i];
5179                                 bbio->stripes[i] = bbio->stripes[i+1];
5180                                 bbio->raid_map[i] = bbio->raid_map[i+1];
5181                                 bbio->stripes[i+1] = s;
5182                                 bbio->raid_map[i+1] = l;
5183
5184                                 again = 1;
5185                         }
5186                 }
5187         }
5188 }
5189
5190 static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
5191 {
5192         struct btrfs_bio *bbio = kzalloc(
5193                  /* the size of the btrfs_bio */
5194                 sizeof(struct btrfs_bio) +
5195                 /* plus the variable array for the stripes */
5196                 sizeof(struct btrfs_bio_stripe) * (total_stripes) +
5197                 /* plus the variable array for the tgt dev */
5198                 sizeof(int) * (real_stripes) +
5199                 /*
5200                  * plus the raid_map, which includes both the tgt dev
5201                  * and the stripes
5202                  */
5203                 sizeof(u64) * (total_stripes),
5204                 GFP_NOFS|__GFP_NOFAIL);
5205
5206         atomic_set(&bbio->error, 0);
5207         atomic_set(&bbio->refs, 1);
5208
5209         return bbio;
5210 }
5211
5212 void btrfs_get_bbio(struct btrfs_bio *bbio)
5213 {
5214         WARN_ON(!atomic_read(&bbio->refs));
5215         atomic_inc(&bbio->refs);
5216 }
5217
5218 void btrfs_put_bbio(struct btrfs_bio *bbio)
5219 {
5220         if (!bbio)
5221                 return;
5222         if (atomic_dec_and_test(&bbio->refs))
5223                 kfree(bbio);
5224 }
5225
5226 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5227                              u64 logical, u64 *length,
5228                              struct btrfs_bio **bbio_ret,
5229                              int mirror_num, int need_raid_map)
5230 {
5231         struct extent_map *em;
5232         struct map_lookup *map;
5233         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5234         struct extent_map_tree *em_tree = &map_tree->map_tree;
5235         u64 offset;
5236         u64 stripe_offset;
5237         u64 stripe_end_offset;
5238         u64 stripe_nr;
5239         u64 stripe_nr_orig;
5240         u64 stripe_nr_end;
5241         u64 stripe_len;
5242         u32 stripe_index;
5243         int i;
5244         int ret = 0;
5245         int num_stripes;
5246         int max_errors = 0;
5247         int tgtdev_indexes = 0;
5248         struct btrfs_bio *bbio = NULL;
5249         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
5250         int dev_replace_is_ongoing = 0;
5251         int num_alloc_stripes;
5252         int patch_the_first_stripe_for_dev_replace = 0;
5253         u64 physical_to_patch_in_first_stripe = 0;
5254         u64 raid56_full_stripe_start = (u64)-1;
5255
5256         read_lock(&em_tree->lock);
5257         em = lookup_extent_mapping(em_tree, logical, *length);
5258         read_unlock(&em_tree->lock);
5259
5260         if (!em) {
5261                 btrfs_crit(fs_info, "unable to find logical %llu len %llu",
5262                         logical, *length);
5263                 return -EINVAL;
5264         }
5265
5266         if (em->start > logical || em->start + em->len < logical) {
5267                 btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
5268                            "found %Lu-%Lu", logical, em->start,
5269                            em->start + em->len);
5270                 free_extent_map(em);
5271                 return -EINVAL;
5272         }
5273
5274         map = em->map_lookup;
5275         offset = logical - em->start;
5276
5277         stripe_len = map->stripe_len;
5278         stripe_nr = offset;
5279         /*
5280          * stripe_nr counts the total number of stripes we have to stride
5281          * to get to this block
5282          */
5283         stripe_nr = div64_u64(stripe_nr, stripe_len);
5284
5285         stripe_offset = stripe_nr * stripe_len;
5286         BUG_ON(offset < stripe_offset);
5287
5288         /* stripe_offset is the offset of this block in its stripe*/
5289         stripe_offset = offset - stripe_offset;
5290
5291         /* if we're here for raid56, we need to know the stripe aligned start */
5292         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5293                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
5294                 raid56_full_stripe_start = offset;
5295
5296                 /* allow a write of a full stripe, but make sure we don't
5297                  * allow straddling of stripes
5298                  */
5299                 raid56_full_stripe_start = div64_u64(raid56_full_stripe_start,
5300                                 full_stripe_len);
5301                 raid56_full_stripe_start *= full_stripe_len;
5302         }
5303
5304         if (rw & REQ_DISCARD) {
5305                 /* we don't discard raid56 yet */
5306                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5307                         ret = -EOPNOTSUPP;
5308                         goto out;
5309                 }
5310                 *length = min_t(u64, em->len - offset, *length);
5311         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
5312                 u64 max_len;
5313                 /* For writes to RAID[56], allow a full stripeset across all disks.
5314                    For other RAID types and for RAID[56] reads, just allow a single
5315                    stripe (on a single disk). */
5316                 if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
5317                     (rw & REQ_WRITE)) {
5318                         max_len = stripe_len * nr_data_stripes(map) -
5319                                 (offset - raid56_full_stripe_start);
5320                 } else {
5321                         /* we limit the length of each bio to what fits in a stripe */
5322                         max_len = stripe_len - stripe_offset;
5323                 }
5324                 *length = min_t(u64, em->len - offset, max_len);
5325         } else {
5326                 *length = em->len - offset;
5327         }
5328
5329         /* This is for when we're called from btrfs_merge_bio_hook() and all
5330            it cares about is the length */
5331         if (!bbio_ret)
5332                 goto out;
5333
5334         btrfs_dev_replace_lock(dev_replace, 0);
5335         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
5336         if (!dev_replace_is_ongoing)
5337                 btrfs_dev_replace_unlock(dev_replace, 0);
5338         else
5339                 btrfs_dev_replace_set_lock_blocking(dev_replace);
5340
5341         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
5342             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
5343             dev_replace->tgtdev != NULL) {
5344                 /*
5345                  * in dev-replace case, for repair case (that's the only
5346                  * case where the mirror is selected explicitly when
5347                  * calling btrfs_map_block), blocks left of the left cursor
5348                  * can also be read from the target drive.
5349                  * For REQ_GET_READ_MIRRORS, the target drive is added as
5350                  * the last one to the array of stripes. For READ, it also
5351                  * needs to be supported using the same mirror number.
5352                  * If the requested block is not left of the left cursor,
5353                  * EIO is returned. This can happen because btrfs_num_copies()
5354                  * returns one more in the dev-replace case.
5355                  */
5356                 u64 tmp_length = *length;
5357                 struct btrfs_bio *tmp_bbio = NULL;
5358                 int tmp_num_stripes;
5359                 u64 srcdev_devid = dev_replace->srcdev->devid;
5360                 int index_srcdev = 0;
5361                 int found = 0;
5362                 u64 physical_of_found = 0;
5363
5364                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
5365                              logical, &tmp_length, &tmp_bbio, 0, 0);
5366                 if (ret) {
5367                         WARN_ON(tmp_bbio != NULL);
5368                         goto out;
5369                 }
5370
5371                 tmp_num_stripes = tmp_bbio->num_stripes;
5372                 if (mirror_num > tmp_num_stripes) {
5373                         /*
5374                          * REQ_GET_READ_MIRRORS does not contain this
5375                          * mirror, that means that the requested area
5376                          * is not left of the left cursor
5377                          */
5378                         ret = -EIO;
5379                         btrfs_put_bbio(tmp_bbio);
5380                         goto out;
5381                 }
5382
5383                 /*
5384                  * process the rest of the function using the mirror_num
5385                  * of the source drive. Therefore look it up first.
5386                  * At the end, patch the device pointer to the one of the
5387                  * target drive.
5388                  */
5389                 for (i = 0; i < tmp_num_stripes; i++) {
5390                         if (tmp_bbio->stripes[i].dev->devid != srcdev_devid)
5391                                 continue;
5392
5393                         /*
5394                          * In case of DUP, in order to keep it simple, only add
5395                          * the mirror with the lowest physical address
5396                          */
5397                         if (found &&
5398                             physical_of_found <= tmp_bbio->stripes[i].physical)
5399                                 continue;
5400
5401                         index_srcdev = i;
5402                         found = 1;
5403                         physical_of_found = tmp_bbio->stripes[i].physical;
5404                 }
5405
5406                 btrfs_put_bbio(tmp_bbio);
5407
5408                 if (!found) {
5409                         WARN_ON(1);
5410                         ret = -EIO;
5411                         goto out;
5412                 }
5413
5414                 mirror_num = index_srcdev + 1;
5415                 patch_the_first_stripe_for_dev_replace = 1;
5416                 physical_to_patch_in_first_stripe = physical_of_found;
5417         } else if (mirror_num > map->num_stripes) {
5418                 mirror_num = 0;
5419         }
5420
5421         num_stripes = 1;
5422         stripe_index = 0;
5423         stripe_nr_orig = stripe_nr;
5424         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
5425         stripe_nr_end = div_u64(stripe_nr_end, map->stripe_len);
5426         stripe_end_offset = stripe_nr_end * map->stripe_len -
5427                             (offset + *length);
5428
5429         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5430                 if (rw & REQ_DISCARD)
5431                         num_stripes = min_t(u64, map->num_stripes,
5432                                             stripe_nr_end - stripe_nr_orig);
5433                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5434                                 &stripe_index);
5435                 if (!(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)))
5436                         mirror_num = 1;
5437         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
5438                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
5439                         num_stripes = map->num_stripes;
5440                 else if (mirror_num)
5441                         stripe_index = mirror_num - 1;
5442                 else {
5443                         stripe_index = find_live_mirror(fs_info, map, 0,
5444                                             map->num_stripes,
5445                                             current->pid % map->num_stripes,
5446                                             dev_replace_is_ongoing);
5447                         mirror_num = stripe_index + 1;
5448                 }
5449
5450         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
5451                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
5452                         num_stripes = map->num_stripes;
5453                 } else if (mirror_num) {
5454                         stripe_index = mirror_num - 1;
5455                 } else {
5456                         mirror_num = 1;
5457                 }
5458
5459         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5460                 u32 factor = map->num_stripes / map->sub_stripes;
5461
5462                 stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
5463                 stripe_index *= map->sub_stripes;
5464
5465                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5466                         num_stripes = map->sub_stripes;
5467                 else if (rw & REQ_DISCARD)
5468                         num_stripes = min_t(u64, map->sub_stripes *
5469                                             (stripe_nr_end - stripe_nr_orig),
5470                                             map->num_stripes);
5471                 else if (mirror_num)
5472                         stripe_index += mirror_num - 1;
5473                 else {
5474                         int old_stripe_index = stripe_index;
5475                         stripe_index = find_live_mirror(fs_info, map,
5476                                               stripe_index,
5477                                               map->sub_stripes, stripe_index +
5478                                               current->pid % map->sub_stripes,
5479                                               dev_replace_is_ongoing);
5480                         mirror_num = stripe_index - old_stripe_index + 1;
5481                 }
5482
5483         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5484                 if (need_raid_map &&
5485                     ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5486                      mirror_num > 1)) {
5487                         /* push stripe_nr back to the start of the full stripe */
5488                         stripe_nr = div_u64(raid56_full_stripe_start,
5489                                         stripe_len * nr_data_stripes(map));
5490
5491                         /* RAID[56] write or recovery. Return all stripes */
5492                         num_stripes = map->num_stripes;
5493                         max_errors = nr_parity_stripes(map);
5494
5495                         *length = map->stripe_len;
5496                         stripe_index = 0;
5497                         stripe_offset = 0;
5498                 } else {
5499                         /*
5500                          * Mirror #0 or #1 means the original data block.
5501                          * Mirror #2 is RAID5 parity block.
5502                          * Mirror #3 is RAID6 Q block.
5503                          */
5504                         stripe_nr = div_u64_rem(stripe_nr,
5505                                         nr_data_stripes(map), &stripe_index);
5506                         if (mirror_num > 1)
5507                                 stripe_index = nr_data_stripes(map) +
5508                                                 mirror_num - 2;
5509
5510                         /* We distribute the parity blocks across stripes */
5511                         div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
5512                                         &stripe_index);
5513                         if (!(rw & (REQ_WRITE | REQ_DISCARD |
5514                                     REQ_GET_READ_MIRRORS)) && mirror_num <= 1)
5515                                 mirror_num = 1;
5516                 }
5517         } else {
5518                 /*
5519                  * after this, stripe_nr is the number of stripes on this
5520                  * device we have to walk to find the data, and stripe_index is
5521                  * the number of our device in the stripe array
5522                  */
5523                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5524                                 &stripe_index);
5525                 mirror_num = stripe_index + 1;
5526         }
5527         BUG_ON(stripe_index >= map->num_stripes);
5528
5529         num_alloc_stripes = num_stripes;
5530         if (dev_replace_is_ongoing) {
5531                 if (rw & (REQ_WRITE | REQ_DISCARD))
5532                         num_alloc_stripes <<= 1;
5533                 if (rw & REQ_GET_READ_MIRRORS)
5534                         num_alloc_stripes++;
5535                 tgtdev_indexes = num_stripes;
5536         }
5537
5538         bbio = alloc_btrfs_bio(num_alloc_stripes, tgtdev_indexes);
5539         if (!bbio) {
5540                 ret = -ENOMEM;
5541                 goto out;
5542         }
5543         if (dev_replace_is_ongoing)
5544                 bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
5545
5546         /* build raid_map */
5547         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK &&
5548             need_raid_map && ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5549             mirror_num > 1)) {
5550                 u64 tmp;
5551                 unsigned rot;
5552
5553                 bbio->raid_map = (u64 *)((void *)bbio->stripes +
5554                                  sizeof(struct btrfs_bio_stripe) *
5555                                  num_alloc_stripes +
5556                                  sizeof(int) * tgtdev_indexes);
5557
5558                 /* Work out the disk rotation on this stripe-set */
5559                 div_u64_rem(stripe_nr, num_stripes, &rot);
5560
5561                 /* Fill in the logical address of each stripe */
5562                 tmp = stripe_nr * nr_data_stripes(map);
5563                 for (i = 0; i < nr_data_stripes(map); i++)
5564                         bbio->raid_map[(i+rot) % num_stripes] =
5565                                 em->start + (tmp + i) * map->stripe_len;
5566
5567                 bbio->raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
5568                 if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5569                         bbio->raid_map[(i+rot+1) % num_stripes] =
5570                                 RAID6_Q_STRIPE;
5571         }
5572
5573         if (rw & REQ_DISCARD) {
5574                 u32 factor = 0;
5575                 u32 sub_stripes = 0;
5576                 u64 stripes_per_dev = 0;
5577                 u32 remaining_stripes = 0;
5578                 u32 last_stripe = 0;
5579
5580                 if (map->type &
5581                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
5582                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5583                                 sub_stripes = 1;
5584                         else
5585                                 sub_stripes = map->sub_stripes;
5586
5587                         factor = map->num_stripes / sub_stripes;
5588                         stripes_per_dev = div_u64_rem(stripe_nr_end -
5589                                                       stripe_nr_orig,
5590                                                       factor,
5591                                                       &remaining_stripes);
5592                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
5593                         last_stripe *= sub_stripes;
5594                 }
5595
5596                 for (i = 0; i < num_stripes; i++) {
5597                         bbio->stripes[i].physical =
5598                                 map->stripes[stripe_index].physical +
5599                                 stripe_offset + stripe_nr * map->stripe_len;
5600                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
5601
5602                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5603                                          BTRFS_BLOCK_GROUP_RAID10)) {
5604                                 bbio->stripes[i].length = stripes_per_dev *
5605                                                           map->stripe_len;
5606
5607                                 if (i / sub_stripes < remaining_stripes)
5608                                         bbio->stripes[i].length +=
5609                                                 map->stripe_len;
5610
5611                                 /*
5612                                  * Special for the first stripe and
5613                                  * the last stripe:
5614                                  *
5615                                  * |-------|...|-------|
5616                                  *     |----------|
5617                                  *    off     end_off
5618                                  */
5619                                 if (i < sub_stripes)
5620                                         bbio->stripes[i].length -=
5621                                                 stripe_offset;
5622
5623                                 if (stripe_index >= last_stripe &&
5624                                     stripe_index <= (last_stripe +
5625                                                      sub_stripes - 1))
5626                                         bbio->stripes[i].length -=
5627                                                 stripe_end_offset;
5628
5629                                 if (i == sub_stripes - 1)
5630                                         stripe_offset = 0;
5631                         } else
5632                                 bbio->stripes[i].length = *length;
5633
5634                         stripe_index++;
5635                         if (stripe_index == map->num_stripes) {
5636                                 /* This could only happen for RAID0/10 */
5637                                 stripe_index = 0;
5638                                 stripe_nr++;
5639                         }
5640                 }
5641         } else {
5642                 for (i = 0; i < num_stripes; i++) {
5643                         bbio->stripes[i].physical =
5644                                 map->stripes[stripe_index].physical +
5645                                 stripe_offset +
5646                                 stripe_nr * map->stripe_len;
5647                         bbio->stripes[i].dev =
5648                                 map->stripes[stripe_index].dev;
5649                         stripe_index++;
5650                 }
5651         }
5652
5653         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5654                 max_errors = btrfs_chunk_max_errors(map);
5655
5656         if (bbio->raid_map)
5657                 sort_parity_stripes(bbio, num_stripes);
5658
5659         tgtdev_indexes = 0;
5660         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
5661             dev_replace->tgtdev != NULL) {
5662                 int index_where_to_add;
5663                 u64 srcdev_devid = dev_replace->srcdev->devid;
5664
5665                 /*
5666                  * duplicate the write operations while the dev replace
5667                  * procedure is running. Since the copying of the old disk
5668                  * to the new disk takes place at run time while the
5669                  * filesystem is mounted writable, the regular write
5670                  * operations to the old disk have to be duplicated to go
5671                  * to the new disk as well.
5672                  * Note that device->missing is handled by the caller, and
5673                  * that the write to the old disk is already set up in the
5674                  * stripes array.
5675                  */
5676                 index_where_to_add = num_stripes;
5677                 for (i = 0; i < num_stripes; i++) {
5678                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5679                                 /* write to new disk, too */
5680                                 struct btrfs_bio_stripe *new =
5681                                         bbio->stripes + index_where_to_add;
5682                                 struct btrfs_bio_stripe *old =
5683                                         bbio->stripes + i;
5684
5685                                 new->physical = old->physical;
5686                                 new->length = old->length;
5687                                 new->dev = dev_replace->tgtdev;
5688                                 bbio->tgtdev_map[i] = index_where_to_add;
5689                                 index_where_to_add++;
5690                                 max_errors++;
5691                                 tgtdev_indexes++;
5692                         }
5693                 }
5694                 num_stripes = index_where_to_add;
5695         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
5696                    dev_replace->tgtdev != NULL) {
5697                 u64 srcdev_devid = dev_replace->srcdev->devid;
5698                 int index_srcdev = 0;
5699                 int found = 0;
5700                 u64 physical_of_found = 0;
5701
5702                 /*
5703                  * During the dev-replace procedure, the target drive can
5704                  * also be used to read data in case it is needed to repair
5705                  * a corrupt block elsewhere. This is possible if the
5706                  * requested area is left of the left cursor. In this area,
5707                  * the target drive is a full copy of the source drive.
5708                  */
5709                 for (i = 0; i < num_stripes; i++) {
5710                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5711                                 /*
5712                                  * In case of DUP, in order to keep it
5713                                  * simple, only add the mirror with the
5714                                  * lowest physical address
5715                                  */
5716                                 if (found &&
5717                                     physical_of_found <=
5718                                      bbio->stripes[i].physical)
5719                                         continue;
5720                                 index_srcdev = i;
5721                                 found = 1;
5722                                 physical_of_found = bbio->stripes[i].physical;
5723                         }
5724                 }
5725                 if (found) {
5726                         if (physical_of_found + map->stripe_len <=
5727                             dev_replace->cursor_left) {
5728                                 struct btrfs_bio_stripe *tgtdev_stripe =
5729                                         bbio->stripes + num_stripes;
5730
5731                                 tgtdev_stripe->physical = physical_of_found;
5732                                 tgtdev_stripe->length =
5733                                         bbio->stripes[index_srcdev].length;
5734                                 tgtdev_stripe->dev = dev_replace->tgtdev;
5735                                 bbio->tgtdev_map[index_srcdev] = num_stripes;
5736
5737                                 tgtdev_indexes++;
5738                                 num_stripes++;
5739                         }
5740                 }
5741         }
5742
5743         *bbio_ret = bbio;
5744         bbio->map_type = map->type;
5745         bbio->num_stripes = num_stripes;
5746         bbio->max_errors = max_errors;
5747         bbio->mirror_num = mirror_num;
5748         bbio->num_tgtdevs = tgtdev_indexes;
5749
5750         /*
5751          * this is the case that REQ_READ && dev_replace_is_ongoing &&
5752          * mirror_num == num_stripes + 1 && dev_replace target drive is
5753          * available as a mirror
5754          */
5755         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
5756                 WARN_ON(num_stripes > 1);
5757                 bbio->stripes[0].dev = dev_replace->tgtdev;
5758                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
5759                 bbio->mirror_num = map->num_stripes + 1;
5760         }
5761 out:
5762         if (dev_replace_is_ongoing) {
5763                 btrfs_dev_replace_clear_lock_blocking(dev_replace);
5764                 btrfs_dev_replace_unlock(dev_replace, 0);
5765         }
5766         free_extent_map(em);
5767         return ret;
5768 }
5769
5770 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5771                       u64 logical, u64 *length,
5772                       struct btrfs_bio **bbio_ret, int mirror_num)
5773 {
5774         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5775                                  mirror_num, 0);
5776 }
5777
5778 /* For Scrub/replace */
5779 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int rw,
5780                      u64 logical, u64 *length,
5781                      struct btrfs_bio **bbio_ret, int mirror_num,
5782                      int need_raid_map)
5783 {
5784         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5785                                  mirror_num, need_raid_map);
5786 }
5787
5788 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
5789                      u64 chunk_start, u64 physical, u64 devid,
5790                      u64 **logical, int *naddrs, int *stripe_len)
5791 {
5792         struct extent_map_tree *em_tree = &map_tree->map_tree;
5793         struct extent_map *em;
5794         struct map_lookup *map;
5795         u64 *buf;
5796         u64 bytenr;
5797         u64 length;
5798         u64 stripe_nr;
5799         u64 rmap_len;
5800         int i, j, nr = 0;
5801
5802         read_lock(&em_tree->lock);
5803         em = lookup_extent_mapping(em_tree, chunk_start, 1);
5804         read_unlock(&em_tree->lock);
5805
5806         if (!em) {
5807                 printk(KERN_ERR "BTRFS: couldn't find em for chunk %Lu\n",
5808                        chunk_start);
5809                 return -EIO;
5810         }
5811
5812         if (em->start != chunk_start) {
5813                 printk(KERN_ERR "BTRFS: bad chunk start, em=%Lu, wanted=%Lu\n",
5814                        em->start, chunk_start);
5815                 free_extent_map(em);
5816                 return -EIO;
5817         }
5818         map = em->map_lookup;
5819
5820         length = em->len;
5821         rmap_len = map->stripe_len;
5822
5823         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5824                 length = div_u64(length, map->num_stripes / map->sub_stripes);
5825         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5826                 length = div_u64(length, map->num_stripes);
5827         else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5828                 length = div_u64(length, nr_data_stripes(map));
5829                 rmap_len = map->stripe_len * nr_data_stripes(map);
5830         }
5831
5832         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
5833         BUG_ON(!buf); /* -ENOMEM */
5834
5835         for (i = 0; i < map->num_stripes; i++) {
5836                 if (devid && map->stripes[i].dev->devid != devid)
5837                         continue;
5838                 if (map->stripes[i].physical > physical ||
5839                     map->stripes[i].physical + length <= physical)
5840                         continue;
5841
5842                 stripe_nr = physical - map->stripes[i].physical;
5843                 stripe_nr = div_u64(stripe_nr, map->stripe_len);
5844
5845                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5846                         stripe_nr = stripe_nr * map->num_stripes + i;
5847                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
5848                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5849                         stripe_nr = stripe_nr * map->num_stripes + i;
5850                 } /* else if RAID[56], multiply by nr_data_stripes().
5851                    * Alternatively, just use rmap_len below instead of
5852                    * map->stripe_len */
5853
5854                 bytenr = chunk_start + stripe_nr * rmap_len;
5855                 WARN_ON(nr >= map->num_stripes);
5856                 for (j = 0; j < nr; j++) {
5857                         if (buf[j] == bytenr)
5858                                 break;
5859                 }
5860                 if (j == nr) {
5861                         WARN_ON(nr >= map->num_stripes);
5862                         buf[nr++] = bytenr;
5863                 }
5864         }
5865
5866         *logical = buf;
5867         *naddrs = nr;
5868         *stripe_len = rmap_len;
5869
5870         free_extent_map(em);
5871         return 0;
5872 }
5873
5874 static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio)
5875 {
5876         bio->bi_private = bbio->private;
5877         bio->bi_end_io = bbio->end_io;
5878         bio_endio(bio);
5879
5880         btrfs_put_bbio(bbio);
5881 }
5882
5883 static void btrfs_end_bio(struct bio *bio)
5884 {
5885         struct btrfs_bio *bbio = bio->bi_private;
5886         int is_orig_bio = 0;
5887
5888         if (bio->bi_error) {
5889                 atomic_inc(&bbio->error);
5890                 if (bio->bi_error == -EIO || bio->bi_error == -EREMOTEIO) {
5891                         unsigned int stripe_index =
5892                                 btrfs_io_bio(bio)->stripe_index;
5893                         struct btrfs_device *dev;
5894
5895                         BUG_ON(stripe_index >= bbio->num_stripes);
5896                         dev = bbio->stripes[stripe_index].dev;
5897                         if (dev->bdev) {
5898                                 if (bio->bi_rw & WRITE)
5899                                         btrfs_dev_stat_inc(dev,
5900                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5901                                 else
5902                                         btrfs_dev_stat_inc(dev,
5903                                                 BTRFS_DEV_STAT_READ_ERRS);
5904                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5905                                         btrfs_dev_stat_inc(dev,
5906                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5907                                 btrfs_dev_stat_print_on_error(dev);
5908                         }
5909                 }
5910         }
5911
5912         if (bio == bbio->orig_bio)
5913                 is_orig_bio = 1;
5914
5915         btrfs_bio_counter_dec(bbio->fs_info);
5916
5917         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5918                 if (!is_orig_bio) {
5919                         bio_put(bio);
5920                         bio = bbio->orig_bio;
5921                 }
5922
5923                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5924                 /* only send an error to the higher layers if it is
5925                  * beyond the tolerance of the btrfs bio
5926                  */
5927                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5928                         bio->bi_error = -EIO;
5929                 } else {
5930                         /*
5931                          * this bio is actually up to date, we didn't
5932                          * go over the max number of errors
5933                          */
5934                         bio->bi_error = 0;
5935                 }
5936
5937                 btrfs_end_bbio(bbio, bio);
5938         } else if (!is_orig_bio) {
5939                 bio_put(bio);
5940         }
5941 }
5942
5943 /*
5944  * see run_scheduled_bios for a description of why bios are collected for
5945  * async submit.
5946  *
5947  * This will add one bio to the pending list for a device and make sure
5948  * the work struct is scheduled.
5949  */
5950 static noinline void btrfs_schedule_bio(struct btrfs_root *root,
5951                                         struct btrfs_device *device,
5952                                         int rw, struct bio *bio)
5953 {
5954         int should_queue = 1;
5955         struct btrfs_pending_bios *pending_bios;
5956
5957         if (device->missing || !device->bdev) {
5958                 bio_io_error(bio);
5959                 return;
5960         }
5961
5962         /* don't bother with additional async steps for reads, right now */
5963         if (!(rw & REQ_WRITE)) {
5964                 bio_get(bio);
5965                 btrfsic_submit_bio(rw, bio);
5966                 bio_put(bio);
5967                 return;
5968         }
5969
5970         /*
5971          * nr_async_bios allows us to reliably return congestion to the
5972          * higher layers.  Otherwise, the async bio makes it appear we have
5973          * made progress against dirty pages when we've really just put it
5974          * on a queue for later
5975          */
5976         atomic_inc(&root->fs_info->nr_async_bios);
5977         WARN_ON(bio->bi_next);
5978         bio->bi_next = NULL;
5979         bio->bi_rw |= rw;
5980
5981         spin_lock(&device->io_lock);
5982         if (bio->bi_rw & REQ_SYNC)
5983                 pending_bios = &device->pending_sync_bios;
5984         else
5985                 pending_bios = &device->pending_bios;
5986
5987         if (pending_bios->tail)
5988                 pending_bios->tail->bi_next = bio;
5989
5990         pending_bios->tail = bio;
5991         if (!pending_bios->head)
5992                 pending_bios->head = bio;
5993         if (device->running_pending)
5994                 should_queue = 0;
5995
5996         spin_unlock(&device->io_lock);
5997
5998         if (should_queue)
5999                 btrfs_queue_work(root->fs_info->submit_workers,
6000                                  &device->work);
6001 }
6002
6003 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
6004                               struct bio *bio, u64 physical, int dev_nr,
6005                               int rw, int async)
6006 {
6007         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
6008
6009         bio->bi_private = bbio;
6010         btrfs_io_bio(bio)->stripe_index = dev_nr;
6011         bio->bi_end_io = btrfs_end_bio;
6012         bio->bi_iter.bi_sector = physical >> 9;
6013 #ifdef DEBUG
6014         {
6015                 struct rcu_string *name;
6016
6017                 rcu_read_lock();
6018                 name = rcu_dereference(dev->name);
6019                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
6020                          "(%s id %llu), size=%u\n", rw,
6021                          (u64)bio->bi_iter.bi_sector, (u_long)dev->bdev->bd_dev,
6022                          name->str, dev->devid, bio->bi_iter.bi_size);
6023                 rcu_read_unlock();
6024         }
6025 #endif
6026         bio->bi_bdev = dev->bdev;
6027
6028         btrfs_bio_counter_inc_noblocked(root->fs_info);
6029
6030         if (async)
6031                 btrfs_schedule_bio(root, dev, rw, bio);
6032         else
6033                 btrfsic_submit_bio(rw, bio);
6034 }
6035
6036 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
6037 {
6038         atomic_inc(&bbio->error);
6039         if (atomic_dec_and_test(&bbio->stripes_pending)) {
6040                 /* Shoud be the original bio. */
6041                 WARN_ON(bio != bbio->orig_bio);
6042
6043                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
6044                 bio->bi_iter.bi_sector = logical >> 9;
6045                 bio->bi_error = -EIO;
6046                 btrfs_end_bbio(bbio, bio);
6047         }
6048 }
6049
6050 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
6051                   int mirror_num, int async_submit)
6052 {
6053         struct btrfs_device *dev;
6054         struct bio *first_bio = bio;
6055         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
6056         u64 length = 0;
6057         u64 map_length;
6058         int ret;
6059         int dev_nr;
6060         int total_devs;
6061         struct btrfs_bio *bbio = NULL;
6062
6063         length = bio->bi_iter.bi_size;
6064         map_length = length;
6065
6066         btrfs_bio_counter_inc_blocked(root->fs_info);
6067         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
6068                               mirror_num, 1);
6069         if (ret) {
6070                 btrfs_bio_counter_dec(root->fs_info);
6071                 return ret;
6072         }
6073
6074         total_devs = bbio->num_stripes;
6075         bbio->orig_bio = first_bio;
6076         bbio->private = first_bio->bi_private;
6077         bbio->end_io = first_bio->bi_end_io;
6078         bbio->fs_info = root->fs_info;
6079         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
6080
6081         if ((bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
6082             ((rw & WRITE) || (mirror_num > 1))) {
6083                 /* In this case, map_length has been set to the length of
6084                    a single stripe; not the whole write */
6085                 if (rw & WRITE) {
6086                         ret = raid56_parity_write(root, bio, bbio, map_length);
6087                 } else {
6088                         ret = raid56_parity_recover(root, bio, bbio, map_length,
6089                                                     mirror_num, 1);
6090                 }
6091
6092                 btrfs_bio_counter_dec(root->fs_info);
6093                 return ret;
6094         }
6095
6096         if (map_length < length) {
6097                 btrfs_crit(root->fs_info, "mapping failed logical %llu bio len %llu len %llu",
6098                         logical, length, map_length);
6099                 BUG();
6100         }
6101
6102         for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
6103                 dev = bbio->stripes[dev_nr].dev;
6104                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
6105                         bbio_error(bbio, first_bio, logical);
6106                         continue;
6107                 }
6108
6109                 if (dev_nr < total_devs - 1) {
6110                         bio = btrfs_bio_clone(first_bio, GFP_NOFS);
6111                         BUG_ON(!bio); /* -ENOMEM */
6112                 } else
6113                         bio = first_bio;
6114
6115                 submit_stripe_bio(root, bbio, bio,
6116                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
6117                                   async_submit);
6118         }
6119         btrfs_bio_counter_dec(root->fs_info);
6120         return 0;
6121 }
6122
6123 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
6124                                        u8 *uuid, u8 *fsid)
6125 {
6126         struct btrfs_device *device;
6127         struct btrfs_fs_devices *cur_devices;
6128
6129         cur_devices = fs_info->fs_devices;
6130         while (cur_devices) {
6131                 if (!fsid ||
6132                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
6133                         device = __find_device(&cur_devices->devices,
6134                                                devid, uuid);
6135                         if (device)
6136                                 return device;
6137                 }
6138                 cur_devices = cur_devices->seed;
6139         }
6140         return NULL;
6141 }
6142
6143 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
6144                                             struct btrfs_fs_devices *fs_devices,
6145                                             u64 devid, u8 *dev_uuid)
6146 {
6147         struct btrfs_device *device;
6148
6149         device = btrfs_alloc_device(NULL, &devid, dev_uuid);
6150         if (IS_ERR(device))
6151                 return NULL;
6152
6153         list_add(&device->dev_list, &fs_devices->devices);
6154         device->fs_devices = fs_devices;
6155         fs_devices->num_devices++;
6156
6157         device->missing = 1;
6158         fs_devices->missing_devices++;
6159
6160         return device;
6161 }
6162
6163 /**
6164  * btrfs_alloc_device - allocate struct btrfs_device
6165  * @fs_info:    used only for generating a new devid, can be NULL if
6166  *              devid is provided (i.e. @devid != NULL).
6167  * @devid:      a pointer to devid for this device.  If NULL a new devid
6168  *              is generated.
6169  * @uuid:       a pointer to UUID for this device.  If NULL a new UUID
6170  *              is generated.
6171  *
6172  * Return: a pointer to a new &struct btrfs_device on success; ERR_PTR()
6173  * on error.  Returned struct is not linked onto any lists and can be
6174  * destroyed with kfree() right away.
6175  */
6176 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
6177                                         const u64 *devid,
6178                                         const u8 *uuid)
6179 {
6180         struct btrfs_device *dev;
6181         u64 tmp;
6182
6183         if (WARN_ON(!devid && !fs_info))
6184                 return ERR_PTR(-EINVAL);
6185
6186         dev = __alloc_device();
6187         if (IS_ERR(dev))
6188                 return dev;
6189
6190         if (devid)
6191                 tmp = *devid;
6192         else {
6193                 int ret;
6194
6195                 ret = find_next_devid(fs_info, &tmp);
6196                 if (ret) {
6197                         kfree(dev);
6198                         return ERR_PTR(ret);
6199                 }
6200         }
6201         dev->devid = tmp;
6202
6203         if (uuid)
6204                 memcpy(dev->uuid, uuid, BTRFS_UUID_SIZE);
6205         else
6206                 generate_random_uuid(dev->uuid);
6207
6208         btrfs_init_work(&dev->work, btrfs_submit_helper,
6209                         pending_bios_fn, NULL, NULL);
6210
6211         return dev;
6212 }
6213
6214 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
6215                           struct extent_buffer *leaf,
6216                           struct btrfs_chunk *chunk)
6217 {
6218         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
6219         struct map_lookup *map;
6220         struct extent_map *em;
6221         u64 logical;
6222         u64 length;
6223         u64 stripe_len;
6224         u64 devid;
6225         u8 uuid[BTRFS_UUID_SIZE];
6226         int num_stripes;
6227         int ret;
6228         int i;
6229
6230         logical = key->offset;
6231         length = btrfs_chunk_length(leaf, chunk);
6232         stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6233         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6234         /* Validation check */
6235         if (!num_stripes) {
6236                 btrfs_err(root->fs_info, "invalid chunk num_stripes: %u",
6237                           num_stripes);
6238                 return -EIO;
6239         }
6240         if (!IS_ALIGNED(logical, root->sectorsize)) {
6241                 btrfs_err(root->fs_info,
6242                           "invalid chunk logical %llu", logical);
6243                 return -EIO;
6244         }
6245         if (!length || !IS_ALIGNED(length, root->sectorsize)) {
6246                 btrfs_err(root->fs_info,
6247                         "invalid chunk length %llu", length);
6248                 return -EIO;
6249         }
6250         if (!is_power_of_2(stripe_len)) {
6251                 btrfs_err(root->fs_info, "invalid chunk stripe length: %llu",
6252                           stripe_len);
6253                 return -EIO;
6254         }
6255         if (~(BTRFS_BLOCK_GROUP_TYPE_MASK | BTRFS_BLOCK_GROUP_PROFILE_MASK) &
6256             btrfs_chunk_type(leaf, chunk)) {
6257                 btrfs_err(root->fs_info, "unrecognized chunk type: %llu",
6258                           ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
6259                             BTRFS_BLOCK_GROUP_PROFILE_MASK) &
6260                           btrfs_chunk_type(leaf, chunk));
6261                 return -EIO;
6262         }
6263
6264         read_lock(&map_tree->map_tree.lock);
6265         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
6266         read_unlock(&map_tree->map_tree.lock);
6267
6268         /* already mapped? */
6269         if (em && em->start <= logical && em->start + em->len > logical) {
6270                 free_extent_map(em);
6271                 return 0;
6272         } else if (em) {
6273                 free_extent_map(em);
6274         }
6275
6276         em = alloc_extent_map();
6277         if (!em)
6278                 return -ENOMEM;
6279         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
6280         if (!map) {
6281                 free_extent_map(em);
6282                 return -ENOMEM;
6283         }
6284
6285         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
6286         em->map_lookup = map;
6287         em->start = logical;
6288         em->len = length;
6289         em->orig_start = 0;
6290         em->block_start = 0;
6291         em->block_len = em->len;
6292
6293         map->num_stripes = num_stripes;
6294         map->io_width = btrfs_chunk_io_width(leaf, chunk);
6295         map->io_align = btrfs_chunk_io_align(leaf, chunk);
6296         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
6297         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6298         map->type = btrfs_chunk_type(leaf, chunk);
6299         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6300         for (i = 0; i < num_stripes; i++) {
6301                 map->stripes[i].physical =
6302                         btrfs_stripe_offset_nr(leaf, chunk, i);
6303                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
6304                 read_extent_buffer(leaf, uuid, (unsigned long)
6305                                    btrfs_stripe_dev_uuid_nr(chunk, i),
6306                                    BTRFS_UUID_SIZE);
6307                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
6308                                                         uuid, NULL);
6309                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
6310                         free_extent_map(em);
6311                         return -EIO;
6312                 }
6313                 if (!map->stripes[i].dev) {
6314                         map->stripes[i].dev =
6315                                 add_missing_dev(root, root->fs_info->fs_devices,
6316                                                 devid, uuid);
6317                         if (!map->stripes[i].dev) {
6318                                 free_extent_map(em);
6319                                 return -EIO;
6320                         }
6321                         btrfs_warn(root->fs_info, "devid %llu uuid %pU is missing",
6322                                                 devid, uuid);
6323                 }
6324                 map->stripes[i].dev->in_fs_metadata = 1;
6325         }
6326
6327         write_lock(&map_tree->map_tree.lock);
6328         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
6329         write_unlock(&map_tree->map_tree.lock);
6330         BUG_ON(ret); /* Tree corruption */
6331         free_extent_map(em);
6332
6333         return 0;
6334 }
6335
6336 static void fill_device_from_item(struct extent_buffer *leaf,
6337                                  struct btrfs_dev_item *dev_item,
6338                                  struct btrfs_device *device)
6339 {
6340         unsigned long ptr;
6341
6342         device->devid = btrfs_device_id(leaf, dev_item);
6343         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
6344         device->total_bytes = device->disk_total_bytes;
6345         device->commit_total_bytes = device->disk_total_bytes;
6346         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
6347         device->commit_bytes_used = device->bytes_used;
6348         device->type = btrfs_device_type(leaf, dev_item);
6349         device->io_align = btrfs_device_io_align(leaf, dev_item);
6350         device->io_width = btrfs_device_io_width(leaf, dev_item);
6351         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
6352         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
6353         device->is_tgtdev_for_dev_replace = 0;
6354
6355         ptr = btrfs_device_uuid(dev_item);
6356         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
6357 }
6358
6359 static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
6360                                                   u8 *fsid)
6361 {
6362         struct btrfs_fs_devices *fs_devices;
6363         int ret;
6364
6365         BUG_ON(!mutex_is_locked(&uuid_mutex));
6366
6367         fs_devices = root->fs_info->fs_devices->seed;
6368         while (fs_devices) {
6369                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE))
6370                         return fs_devices;
6371
6372                 fs_devices = fs_devices->seed;
6373         }
6374
6375         fs_devices = find_fsid(fsid);
6376         if (!fs_devices) {
6377                 if (!btrfs_test_opt(root, DEGRADED))
6378                         return ERR_PTR(-ENOENT);
6379
6380                 fs_devices = alloc_fs_devices(fsid);
6381                 if (IS_ERR(fs_devices))
6382                         return fs_devices;
6383
6384                 fs_devices->seeding = 1;
6385                 fs_devices->opened = 1;
6386                 return fs_devices;
6387         }
6388
6389         fs_devices = clone_fs_devices(fs_devices);
6390         if (IS_ERR(fs_devices))
6391                 return fs_devices;
6392
6393         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
6394                                    root->fs_info->bdev_holder);
6395         if (ret) {
6396                 free_fs_devices(fs_devices);
6397                 fs_devices = ERR_PTR(ret);
6398                 goto out;
6399         }
6400
6401         if (!fs_devices->seeding) {
6402                 __btrfs_close_devices(fs_devices);
6403                 free_fs_devices(fs_devices);
6404                 fs_devices = ERR_PTR(-EINVAL);
6405                 goto out;
6406         }
6407
6408         fs_devices->seed = root->fs_info->fs_devices->seed;
6409         root->fs_info->fs_devices->seed = fs_devices;
6410 out:
6411         return fs_devices;
6412 }
6413
6414 static int read_one_dev(struct btrfs_root *root,
6415                         struct extent_buffer *leaf,
6416                         struct btrfs_dev_item *dev_item)
6417 {
6418         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6419         struct btrfs_device *device;
6420         u64 devid;
6421         int ret;
6422         u8 fs_uuid[BTRFS_UUID_SIZE];
6423         u8 dev_uuid[BTRFS_UUID_SIZE];
6424
6425         devid = btrfs_device_id(leaf, dev_item);
6426         read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
6427                            BTRFS_UUID_SIZE);
6428         read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
6429                            BTRFS_UUID_SIZE);
6430
6431         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
6432                 fs_devices = open_seed_devices(root, fs_uuid);
6433                 if (IS_ERR(fs_devices))
6434                         return PTR_ERR(fs_devices);
6435         }
6436
6437         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
6438         if (!device) {
6439                 if (!btrfs_test_opt(root, DEGRADED))
6440                         return -EIO;
6441
6442                 device = add_missing_dev(root, fs_devices, devid, dev_uuid);
6443                 if (!device)
6444                         return -ENOMEM;
6445                 btrfs_warn(root->fs_info, "devid %llu uuid %pU missing",
6446                                 devid, dev_uuid);
6447         } else {
6448                 if (!device->bdev && !btrfs_test_opt(root, DEGRADED))
6449                         return -EIO;
6450
6451                 if(!device->bdev && !device->missing) {
6452                         /*
6453                          * this happens when a device that was properly setup
6454                          * in the device info lists suddenly goes bad.
6455                          * device->bdev is NULL, and so we have to set
6456                          * device->missing to one here
6457                          */
6458                         device->fs_devices->missing_devices++;
6459                         device->missing = 1;
6460                 }
6461
6462                 /* Move the device to its own fs_devices */
6463                 if (device->fs_devices != fs_devices) {
6464                         ASSERT(device->missing);
6465
6466                         list_move(&device->dev_list, &fs_devices->devices);
6467                         device->fs_devices->num_devices--;
6468                         fs_devices->num_devices++;
6469
6470                         device->fs_devices->missing_devices--;
6471                         fs_devices->missing_devices++;
6472
6473                         device->fs_devices = fs_devices;
6474                 }
6475         }
6476
6477         if (device->fs_devices != root->fs_info->fs_devices) {
6478                 BUG_ON(device->writeable);
6479                 if (device->generation !=
6480                     btrfs_device_generation(leaf, dev_item))
6481                         return -EINVAL;
6482         }
6483
6484         fill_device_from_item(leaf, dev_item, device);
6485         device->in_fs_metadata = 1;
6486         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
6487                 device->fs_devices->total_rw_bytes += device->total_bytes;
6488                 spin_lock(&root->fs_info->free_chunk_lock);
6489                 root->fs_info->free_chunk_space += device->total_bytes -
6490                         device->bytes_used;
6491                 spin_unlock(&root->fs_info->free_chunk_lock);
6492         }
6493         ret = 0;
6494         return ret;
6495 }
6496
6497 int btrfs_read_sys_array(struct btrfs_root *root)
6498 {
6499         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
6500         struct extent_buffer *sb;
6501         struct btrfs_disk_key *disk_key;
6502         struct btrfs_chunk *chunk;
6503         u8 *array_ptr;
6504         unsigned long sb_array_offset;
6505         int ret = 0;
6506         u32 num_stripes;
6507         u32 array_size;
6508         u32 len = 0;
6509         u32 cur_offset;
6510         struct btrfs_key key;
6511
6512         ASSERT(BTRFS_SUPER_INFO_SIZE <= root->nodesize);
6513         /*
6514          * This will create extent buffer of nodesize, superblock size is
6515          * fixed to BTRFS_SUPER_INFO_SIZE. If nodesize > sb size, this will
6516          * overallocate but we can keep it as-is, only the first page is used.
6517          */
6518         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET);
6519         if (!sb)
6520                 return -ENOMEM;
6521         set_extent_buffer_uptodate(sb);
6522         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
6523         /*
6524          * The sb extent buffer is artifical and just used to read the system array.
6525          * set_extent_buffer_uptodate() call does not properly mark all it's
6526          * pages up-to-date when the page is larger: extent does not cover the
6527          * whole page and consequently check_page_uptodate does not find all
6528          * the page's extents up-to-date (the hole beyond sb),
6529          * write_extent_buffer then triggers a WARN_ON.
6530          *
6531          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
6532          * but sb spans only this function. Add an explicit SetPageUptodate call
6533          * to silence the warning eg. on PowerPC 64.
6534          */
6535         if (PAGE_SIZE > BTRFS_SUPER_INFO_SIZE)
6536                 SetPageUptodate(sb->pages[0]);
6537
6538         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
6539         array_size = btrfs_super_sys_array_size(super_copy);
6540
6541         array_ptr = super_copy->sys_chunk_array;
6542         sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
6543         cur_offset = 0;
6544
6545         while (cur_offset < array_size) {
6546                 disk_key = (struct btrfs_disk_key *)array_ptr;
6547                 len = sizeof(*disk_key);
6548                 if (cur_offset + len > array_size)
6549                         goto out_short_read;
6550
6551                 btrfs_disk_key_to_cpu(&key, disk_key);
6552
6553                 array_ptr += len;
6554                 sb_array_offset += len;
6555                 cur_offset += len;
6556
6557                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
6558                         chunk = (struct btrfs_chunk *)sb_array_offset;
6559                         /*
6560                          * At least one btrfs_chunk with one stripe must be
6561                          * present, exact stripe count check comes afterwards
6562                          */
6563                         len = btrfs_chunk_item_size(1);
6564                         if (cur_offset + len > array_size)
6565                                 goto out_short_read;
6566
6567                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
6568                         if (!num_stripes) {
6569                                 printk(KERN_ERR
6570             "BTRFS: invalid number of stripes %u in sys_array at offset %u\n",
6571                                         num_stripes, cur_offset);
6572                                 ret = -EIO;
6573                                 break;
6574                         }
6575
6576                         len = btrfs_chunk_item_size(num_stripes);
6577                         if (cur_offset + len > array_size)
6578                                 goto out_short_read;
6579
6580                         ret = read_one_chunk(root, &key, sb, chunk);
6581                         if (ret)
6582                                 break;
6583                 } else {
6584                         printk(KERN_ERR
6585                 "BTRFS: unexpected item type %u in sys_array at offset %u\n",
6586                                 (u32)key.type, cur_offset);
6587                         ret = -EIO;
6588                         break;
6589                 }
6590                 array_ptr += len;
6591                 sb_array_offset += len;
6592                 cur_offset += len;
6593         }
6594         free_extent_buffer(sb);
6595         return ret;
6596
6597 out_short_read:
6598         printk(KERN_ERR "BTRFS: sys_array too short to read %u bytes at offset %u\n",
6599                         len, cur_offset);
6600         free_extent_buffer(sb);
6601         return -EIO;
6602 }
6603
6604 int btrfs_read_chunk_tree(struct btrfs_root *root)
6605 {
6606         struct btrfs_path *path;
6607         struct extent_buffer *leaf;
6608         struct btrfs_key key;
6609         struct btrfs_key found_key;
6610         int ret;
6611         int slot;
6612
6613         root = root->fs_info->chunk_root;
6614
6615         path = btrfs_alloc_path();
6616         if (!path)
6617                 return -ENOMEM;
6618
6619         mutex_lock(&uuid_mutex);
6620         lock_chunks(root);
6621
6622         /*
6623          * Read all device items, and then all the chunk items. All
6624          * device items are found before any chunk item (their object id
6625          * is smaller than the lowest possible object id for a chunk
6626          * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
6627          */
6628         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
6629         key.offset = 0;
6630         key.type = 0;
6631         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6632         if (ret < 0)
6633                 goto error;
6634         while (1) {
6635                 leaf = path->nodes[0];
6636                 slot = path->slots[0];
6637                 if (slot >= btrfs_header_nritems(leaf)) {
6638                         ret = btrfs_next_leaf(root, path);
6639                         if (ret == 0)
6640                                 continue;
6641                         if (ret < 0)
6642                                 goto error;
6643                         break;
6644                 }
6645                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6646                 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
6647                         struct btrfs_dev_item *dev_item;
6648                         dev_item = btrfs_item_ptr(leaf, slot,
6649                                                   struct btrfs_dev_item);
6650                         ret = read_one_dev(root, leaf, dev_item);
6651                         if (ret)
6652                                 goto error;
6653                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
6654                         struct btrfs_chunk *chunk;
6655                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
6656                         ret = read_one_chunk(root, &found_key, leaf, chunk);
6657                         if (ret)
6658                                 goto error;
6659                 }
6660                 path->slots[0]++;
6661         }
6662         ret = 0;
6663 error:
6664         unlock_chunks(root);
6665         mutex_unlock(&uuid_mutex);
6666
6667         btrfs_free_path(path);
6668         return ret;
6669 }
6670
6671 void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
6672 {
6673         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6674         struct btrfs_device *device;
6675
6676         while (fs_devices) {
6677                 mutex_lock(&fs_devices->device_list_mutex);
6678                 list_for_each_entry(device, &fs_devices->devices, dev_list)
6679                         device->dev_root = fs_info->dev_root;
6680                 mutex_unlock(&fs_devices->device_list_mutex);
6681
6682                 fs_devices = fs_devices->seed;
6683         }
6684 }
6685
6686 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
6687 {
6688         int i;
6689
6690         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6691                 btrfs_dev_stat_reset(dev, i);
6692 }
6693
6694 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
6695 {
6696         struct btrfs_key key;
6697         struct btrfs_key found_key;
6698         struct btrfs_root *dev_root = fs_info->dev_root;
6699         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6700         struct extent_buffer *eb;
6701         int slot;
6702         int ret = 0;
6703         struct btrfs_device *device;
6704         struct btrfs_path *path = NULL;
6705         int i;
6706
6707         path = btrfs_alloc_path();
6708         if (!path) {
6709                 ret = -ENOMEM;
6710                 goto out;
6711         }
6712
6713         mutex_lock(&fs_devices->device_list_mutex);
6714         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6715                 int item_size;
6716                 struct btrfs_dev_stats_item *ptr;
6717
6718                 key.objectid = BTRFS_DEV_STATS_OBJECTID;
6719                 key.type = BTRFS_PERSISTENT_ITEM_KEY;
6720                 key.offset = device->devid;
6721                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
6722                 if (ret) {
6723                         __btrfs_reset_dev_stats(device);
6724                         device->dev_stats_valid = 1;
6725                         btrfs_release_path(path);
6726                         continue;
6727                 }
6728                 slot = path->slots[0];
6729                 eb = path->nodes[0];
6730                 btrfs_item_key_to_cpu(eb, &found_key, slot);
6731                 item_size = btrfs_item_size_nr(eb, slot);
6732
6733                 ptr = btrfs_item_ptr(eb, slot,
6734                                      struct btrfs_dev_stats_item);
6735
6736                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6737                         if (item_size >= (1 + i) * sizeof(__le64))
6738                                 btrfs_dev_stat_set(device, i,
6739                                         btrfs_dev_stats_value(eb, ptr, i));
6740                         else
6741                                 btrfs_dev_stat_reset(device, i);
6742                 }
6743
6744                 device->dev_stats_valid = 1;
6745                 btrfs_dev_stat_print_on_load(device);
6746                 btrfs_release_path(path);
6747         }
6748         mutex_unlock(&fs_devices->device_list_mutex);
6749
6750 out:
6751         btrfs_free_path(path);
6752         return ret < 0 ? ret : 0;
6753 }
6754
6755 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
6756                                 struct btrfs_root *dev_root,
6757                                 struct btrfs_device *device)
6758 {
6759         struct btrfs_path *path;
6760         struct btrfs_key key;
6761         struct extent_buffer *eb;
6762         struct btrfs_dev_stats_item *ptr;
6763         int ret;
6764         int i;
6765
6766         key.objectid = BTRFS_DEV_STATS_OBJECTID;
6767         key.type = BTRFS_PERSISTENT_ITEM_KEY;
6768         key.offset = device->devid;
6769
6770         path = btrfs_alloc_path();
6771         BUG_ON(!path);
6772         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
6773         if (ret < 0) {
6774                 btrfs_warn_in_rcu(dev_root->fs_info,
6775                         "error %d while searching for dev_stats item for device %s",
6776                               ret, rcu_str_deref(device->name));
6777                 goto out;
6778         }
6779
6780         if (ret == 0 &&
6781             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
6782                 /* need to delete old one and insert a new one */
6783                 ret = btrfs_del_item(trans, dev_root, path);
6784                 if (ret != 0) {
6785                         btrfs_warn_in_rcu(dev_root->fs_info,
6786                                 "delete too small dev_stats item for device %s failed %d",
6787                                       rcu_str_deref(device->name), ret);
6788                         goto out;
6789                 }
6790                 ret = 1;
6791         }
6792
6793         if (ret == 1) {
6794                 /* need to insert a new item */
6795                 btrfs_release_path(path);
6796                 ret = btrfs_insert_empty_item(trans, dev_root, path,
6797                                               &key, sizeof(*ptr));
6798                 if (ret < 0) {
6799                         btrfs_warn_in_rcu(dev_root->fs_info,
6800                                 "insert dev_stats item for device %s failed %d",
6801                                 rcu_str_deref(device->name), ret);
6802                         goto out;
6803                 }
6804         }
6805
6806         eb = path->nodes[0];
6807         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
6808         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6809                 btrfs_set_dev_stats_value(eb, ptr, i,
6810                                           btrfs_dev_stat_read(device, i));
6811         btrfs_mark_buffer_dirty(eb);
6812
6813 out:
6814         btrfs_free_path(path);
6815         return ret;
6816 }
6817
6818 /*
6819  * called from commit_transaction. Writes all changed device stats to disk.
6820  */
6821 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
6822                         struct btrfs_fs_info *fs_info)
6823 {
6824         struct btrfs_root *dev_root = fs_info->dev_root;
6825         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6826         struct btrfs_device *device;
6827         int stats_cnt;
6828         int ret = 0;
6829
6830         mutex_lock(&fs_devices->device_list_mutex);
6831         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6832                 if (!device->dev_stats_valid || !btrfs_dev_stats_dirty(device))
6833                         continue;
6834
6835                 stats_cnt = atomic_read(&device->dev_stats_ccnt);
6836                 ret = update_dev_stat_item(trans, dev_root, device);
6837                 if (!ret)
6838                         atomic_sub(stats_cnt, &device->dev_stats_ccnt);
6839         }
6840         mutex_unlock(&fs_devices->device_list_mutex);
6841
6842         return ret;
6843 }
6844
6845 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
6846 {
6847         btrfs_dev_stat_inc(dev, index);
6848         btrfs_dev_stat_print_on_error(dev);
6849 }
6850
6851 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
6852 {
6853         if (!dev->dev_stats_valid)
6854                 return;
6855         btrfs_err_rl_in_rcu(dev->dev_root->fs_info,
6856                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6857                            rcu_str_deref(dev->name),
6858                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6859                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6860                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6861                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6862                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6863 }
6864
6865 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
6866 {
6867         int i;
6868
6869         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6870                 if (btrfs_dev_stat_read(dev, i) != 0)
6871                         break;
6872         if (i == BTRFS_DEV_STAT_VALUES_MAX)
6873                 return; /* all values == 0, suppress message */
6874
6875         btrfs_info_in_rcu(dev->dev_root->fs_info,
6876                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6877                rcu_str_deref(dev->name),
6878                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6879                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6880                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6881                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6882                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6883 }
6884
6885 int btrfs_get_dev_stats(struct btrfs_root *root,
6886                         struct btrfs_ioctl_get_dev_stats *stats)
6887 {
6888         struct btrfs_device *dev;
6889         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6890         int i;
6891
6892         mutex_lock(&fs_devices->device_list_mutex);
6893         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
6894         mutex_unlock(&fs_devices->device_list_mutex);
6895
6896         if (!dev) {
6897                 btrfs_warn(root->fs_info, "get dev_stats failed, device not found");
6898                 return -ENODEV;
6899         } else if (!dev->dev_stats_valid) {
6900                 btrfs_warn(root->fs_info, "get dev_stats failed, not yet valid");
6901                 return -ENODEV;
6902         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
6903                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6904                         if (stats->nr_items > i)
6905                                 stats->values[i] =
6906                                         btrfs_dev_stat_read_and_reset(dev, i);
6907                         else
6908                                 btrfs_dev_stat_reset(dev, i);
6909                 }
6910         } else {
6911                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6912                         if (stats->nr_items > i)
6913                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
6914         }
6915         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
6916                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
6917         return 0;
6918 }
6919
6920 void btrfs_scratch_superblocks(struct block_device *bdev, char *device_path)
6921 {
6922         struct buffer_head *bh;
6923         struct btrfs_super_block *disk_super;
6924         int copy_num;
6925
6926         if (!bdev)
6927                 return;
6928
6929         for (copy_num = 0; copy_num < BTRFS_SUPER_MIRROR_MAX;
6930                 copy_num++) {
6931
6932                 if (btrfs_read_dev_one_super(bdev, copy_num, &bh))
6933                         continue;
6934
6935                 disk_super = (struct btrfs_super_block *)bh->b_data;
6936
6937                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
6938                 set_buffer_dirty(bh);
6939                 sync_dirty_buffer(bh);
6940                 brelse(bh);
6941         }
6942
6943         /* Notify udev that device has changed */
6944         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
6945
6946         /* Update ctime/mtime for device path for libblkid */
6947         update_dev_time(device_path);
6948 }
6949
6950 /*
6951  * Update the size of all devices, which is used for writing out the
6952  * super blocks.
6953  */
6954 void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
6955 {
6956         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6957         struct btrfs_device *curr, *next;
6958
6959         if (list_empty(&fs_devices->resized_devices))
6960                 return;
6961
6962         mutex_lock(&fs_devices->device_list_mutex);
6963         lock_chunks(fs_info->dev_root);
6964         list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
6965                                  resized_list) {
6966                 list_del_init(&curr->resized_list);
6967                 curr->commit_total_bytes = curr->disk_total_bytes;
6968         }
6969         unlock_chunks(fs_info->dev_root);
6970         mutex_unlock(&fs_devices->device_list_mutex);
6971 }
6972
6973 /* Must be invoked during the transaction commit */
6974 void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
6975                                         struct btrfs_transaction *transaction)
6976 {
6977         struct extent_map *em;
6978         struct map_lookup *map;
6979         struct btrfs_device *dev;
6980         int i;
6981
6982         if (list_empty(&transaction->pending_chunks))
6983                 return;
6984
6985         /* In order to kick the device replace finish process */
6986         lock_chunks(root);
6987         list_for_each_entry(em, &transaction->pending_chunks, list) {
6988                 map = em->map_lookup;
6989
6990                 for (i = 0; i < map->num_stripes; i++) {
6991                         dev = map->stripes[i].dev;
6992                         dev->commit_bytes_used = dev->bytes_used;
6993                 }
6994         }
6995         unlock_chunks(root);
6996 }
6997
6998 void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)
6999 {
7000         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7001         while (fs_devices) {
7002                 fs_devices->fs_info = fs_info;
7003                 fs_devices = fs_devices->seed;
7004         }
7005 }
7006
7007 void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info)
7008 {
7009         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7010         while (fs_devices) {
7011                 fs_devices->fs_info = NULL;
7012                 fs_devices = fs_devices->seed;
7013         }
7014 }
7015
7016 static void btrfs_close_one_device(struct btrfs_device *device)
7017 {
7018         struct btrfs_fs_devices *fs_devices = device->fs_devices;
7019         struct btrfs_device *new_device;
7020         struct rcu_string *name;
7021
7022         if (device->bdev)
7023                 fs_devices->open_devices--;
7024
7025         if (device->writeable &&
7026             device->devid != BTRFS_DEV_REPLACE_DEVID) {
7027                 list_del_init(&device->dev_alloc_list);
7028                 fs_devices->rw_devices--;
7029         }
7030
7031         if (device->missing)
7032                 fs_devices->missing_devices--;
7033
7034         new_device = btrfs_alloc_device(NULL, &device->devid,
7035                                         device->uuid);
7036         BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
7037
7038         /* Safe because we are under uuid_mutex */
7039         if (device->name) {
7040                 name = rcu_string_strdup(device->name->str, GFP_NOFS);
7041                 BUG_ON(!name); /* -ENOMEM */
7042                 rcu_assign_pointer(new_device->name, name);
7043         }
7044
7045         list_replace_rcu(&device->dev_list, &new_device->dev_list);
7046         new_device->fs_devices = device->fs_devices;
7047
7048         call_rcu(&device->rcu, free_device);
7049 }