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 "compat.h"
  29 #include "ctree.h"
  30 #include "extent_map.h"
  31 #include "disk-io.h"
  32 #include "transaction.h"
  33 #include "print-tree.h"
  34 #include "volumes.h"
  35 #include "async-thread.h"
  36 #include "check-integrity.h"
  37 #include "rcu-string.h"
  38 #include "math.h"
  39
  40 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  41                                 struct btrfs_root *root,
  42                                 struct btrfs_device *device);
  43 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  44 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  45 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  46
  47 static DEFINE_MUTEX(uuid_mutex);
  48 static LIST_HEAD(fs_uuids);
  49
  50 static void lock_chunks(struct btrfs_root *root)
  51 {
  52         mutex_lock(&root->fs_info->chunk_mutex);
  53 }
  54
  55 static void unlock_chunks(struct btrfs_root *root)
  56 {
  57         mutex_unlock(&root->fs_info->chunk_mutex);
  58 }
  59
  60 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  61 {
  62         struct btrfs_device *device;
  63         WARN_ON(fs_devices->opened);
  64         while (!list_empty(&fs_devices->devices)) {
  65                 device = list_entry(fs_devices->devices.next,
  66                                     struct btrfs_device, dev_list);
  67                 list_del(&device->dev_list);
  68                 rcu_string_free(device->name);
  69                 kfree(device);
  70         }
  71         kfree(fs_devices);
  72 }
  73
  74 void btrfs_cleanup_fs_uuids(void)
  75 {
  76         struct btrfs_fs_devices *fs_devices;
  77
  78         while (!list_empty(&fs_uuids)) {
  79                 fs_devices = list_entry(fs_uuids.next,
  80                                         struct btrfs_fs_devices, list);
  81                 list_del(&fs_devices->list);
  82                 free_fs_devices(fs_devices);
  83         }
  84 }
  85
  86 static noinline struct btrfs_device *__find_device(struct list_head *head,
  87                                                    u64 devid, u8 *uuid)
  88 {
  89         struct btrfs_device *dev;
  90
  91         list_for_each_entry(dev, head, dev_list) {
  92                 if (dev->devid == devid &&
  93                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
  94                         return dev;
  95                 }
  96         }
  97         return NULL;
  98 }
  99
 100 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 101 {
 102         struct btrfs_fs_devices *fs_devices;
 103
 104         list_for_each_entry(fs_devices, &fs_uuids, list) {
 105                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 106                         return fs_devices;
 107         }
 108         return NULL;
 109 }
 110
 111 static int
 112 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 113                       int flush, struct block_device **bdev,
 114                       struct buffer_head **bh)
 115 {
 116         int ret;
 117
 118         *bdev = blkdev_get_by_path(device_path, flags, holder);
 119
 120         if (IS_ERR(*bdev)) {
 121                 ret = PTR_ERR(*bdev);
 122                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
 123                 goto error;
 124         }
 125
 126         if (flush)
 127                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 128         ret = set_blocksize(*bdev, 4096);
 129         if (ret) {
 130                 blkdev_put(*bdev, flags);
 131                 goto error;
 132         }
 133         invalidate_bdev(*bdev);
 134         *bh = btrfs_read_dev_super(*bdev);
 135         if (!*bh) {
 136                 ret = -EINVAL;
 137                 blkdev_put(*bdev, flags);
 138                 goto error;
 139         }
 140
 141         return 0;
 142
 143 error:
 144         *bdev = NULL;
 145         *bh = NULL;
 146         return ret;
 147 }
 148
 149 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 150                         struct bio *head, struct bio *tail)
 151 {
 152
 153         struct bio *old_head;
 154
 155         old_head = pending_bios->head;
 156         pending_bios->head = head;
 157         if (pending_bios->tail)
 158                 tail->bi_next = old_head;
 159         else
 160                 pending_bios->tail = tail;
 161 }
 162
 163 /*
 164  * we try to collect pending bios for a device so we don't get a large
 165  * number of procs sending bios down to the same device.  This greatly
 166  * improves the schedulers ability to collect and merge the bios.
 167  *
 168  * But, it also turns into a long list of bios to process and that is sure
 169  * to eventually make the worker thread block.  The solution here is to
 170  * make some progress and then put this work struct back at the end of
 171  * the list if the block device is congested.  This way, multiple devices
 172  * can make progress from a single worker thread.
 173  */
 174 static noinline void run_scheduled_bios(struct btrfs_device *device)
 175 {
 176         struct bio *pending;
 177         struct backing_dev_info *bdi;
 178         struct btrfs_fs_info *fs_info;
 179         struct btrfs_pending_bios *pending_bios;
 180         struct bio *tail;
 181         struct bio *cur;
 182         int again = 0;
 183         unsigned long num_run;
 184         unsigned long batch_run = 0;
 185         unsigned long limit;
 186         unsigned long last_waited = 0;
 187         int force_reg = 0;
 188         int sync_pending = 0;
 189         struct blk_plug plug;
 190
 191         /*
 192          * this function runs all the bios we've collected for
 193          * a particular device.  We don't want to wander off to
 194          * another device without first sending all of these down.
 195          * So, setup a plug here and finish it off before we return
 196          */
 197         blk_start_plug(&plug);
 198
 199         bdi = blk_get_backing_dev_info(device->bdev);
 200         fs_info = device->dev_root->fs_info;
 201         limit = btrfs_async_submit_limit(fs_info);
 202         limit = limit * 2 / 3;
 203
 204 loop:
 205         spin_lock(&device->io_lock);
 206
 207 loop_lock:
 208         num_run = 0;
 209
 210         /* take all the bios off the list at once and process them
 211          * later on (without the lock held).  But, remember the
 212          * tail and other pointers so the bios can be properly reinserted
 213          * into the list if we hit congestion
 214          */
 215         if (!force_reg && device->pending_sync_bios.head) {
 216                 pending_bios = &device->pending_sync_bios;
 217                 force_reg = 1;
 218         } else {
 219                 pending_bios = &device->pending_bios;
 220                 force_reg = 0;
 221         }
 222
 223         pending = pending_bios->head;
 224         tail = pending_bios->tail;
 225         WARN_ON(pending && !tail);
 226
 227         /*
 228          * if pending was null this time around, no bios need processing
 229          * at all and we can stop.  Otherwise it'll loop back up again
 230          * and do an additional check so no bios are missed.
 231          *
 232          * device->running_pending is used to synchronize with the
 233          * schedule_bio code.
 234          */
 235         if (device->pending_sync_bios.head == NULL &&
 236             device->pending_bios.head == NULL) {
 237                 again = 0;
 238                 device->running_pending = 0;
 239         } else {
 240                 again = 1;
 241                 device->running_pending = 1;
 242         }
 243
 244         pending_bios->head = NULL;
 245         pending_bios->tail = NULL;
 246
 247         spin_unlock(&device->io_lock);
 248
 249         while (pending) {
 250
 251                 rmb();
 252                 /* we want to work on both lists, but do more bios on the
 253                  * sync list than the regular list
 254                  */
 255                 if ((num_run > 32 &&
 256                     pending_bios != &device->pending_sync_bios &&
 257                     device->pending_sync_bios.head) ||
 258                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 259                     device->pending_bios.head)) {
 260                         spin_lock(&device->io_lock);
 261                         requeue_list(pending_bios, pending, tail);
 262                         goto loop_lock;
 263                 }
 264
 265                 cur = pending;
 266                 pending = pending->bi_next;
 267                 cur->bi_next = NULL;
 268
 269                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 270                     waitqueue_active(&fs_info->async_submit_wait))
 271                         wake_up(&fs_info->async_submit_wait);
 272
 273                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 274
 275                 /*
 276                  * if we're doing the sync list, record that our
 277                  * plug has some sync requests on it
 278                  *
 279                  * If we're doing the regular list and there are
 280                  * sync requests sitting around, unplug before
 281                  * we add more
 282                  */
 283                 if (pending_bios == &device->pending_sync_bios) {
 284                         sync_pending = 1;
 285                 } else if (sync_pending) {
 286                         blk_finish_plug(&plug);
 287                         blk_start_plug(&plug);
 288                         sync_pending = 0;
 289                 }
 290
 291                 btrfsic_submit_bio(cur->bi_rw, cur);
 292                 num_run++;
 293                 batch_run++;
 294                 if (need_resched())
 295                         cond_resched();
 296
 297                 /*
 298                  * we made progress, there is more work to do and the bdi
 299                  * is now congested.  Back off and let other work structs
 300                  * run instead
 301                  */
 302                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 303                     fs_info->fs_devices->open_devices > 1) {
 304                         struct io_context *ioc;
 305
 306                         ioc = current->io_context;
 307
 308                         /*
 309                          * the main goal here is that we don't want to
 310                          * block if we're going to be able to submit
 311                          * more requests without blocking.
 312                          *
 313                          * This code does two great things, it pokes into
 314                          * the elevator code from a filesystem _and_
 315                          * it makes assumptions about how batching works.
 316                          */
 317                         if (ioc && ioc->nr_batch_requests > 0 &&
 318                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 319                             (last_waited == 0 ||
 320                              ioc->last_waited == last_waited)) {
 321                                 /*
 322                                  * we want to go through our batch of
 323                                  * requests and stop.  So, we copy out
 324                                  * the ioc->last_waited time and test
 325                                  * against it before looping
 326                                  */
 327                                 last_waited = ioc->last_waited;
 328                                 if (need_resched())
 329                                         cond_resched();
 330                                 continue;
 331                         }
 332                         spin_lock(&device->io_lock);
 333                         requeue_list(pending_bios, pending, tail);
 334                         device->running_pending = 1;
 335
 336                         spin_unlock(&device->io_lock);
 337                         btrfs_requeue_work(&device->work);
 338                         goto done;
 339                 }
 340                 /* unplug every 64 requests just for good measure */
 341                 if (batch_run % 64 == 0) {
 342                         blk_finish_plug(&plug);
 343                         blk_start_plug(&plug);
 344                         sync_pending = 0;
 345                 }
 346         }
 347
 348         cond_resched();
 349         if (again)
 350                 goto loop;
 351
 352         spin_lock(&device->io_lock);
 353         if (device->pending_bios.head || device->pending_sync_bios.head)
 354                 goto loop_lock;
 355         spin_unlock(&device->io_lock);
 356
 357 done:
 358         blk_finish_plug(&plug);
 359 }
 360
 361 static void pending_bios_fn(struct btrfs_work *work)
 362 {
 363         struct btrfs_device *device;
 364
 365         device = container_of(work, struct btrfs_device, work);
 366         run_scheduled_bios(device);
 367 }
 368
 369 static noinline int device_list_add(const char *path,
 370                            struct btrfs_super_block *disk_super,
 371                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 372 {
 373         struct btrfs_device *device;
 374         struct btrfs_fs_devices *fs_devices;
 375         struct rcu_string *name;
 376         u64 found_transid = btrfs_super_generation(disk_super);
 377
 378         fs_devices = find_fsid(disk_super->fsid);
 379         if (!fs_devices) {
 380                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 381                 if (!fs_devices)
 382                         return -ENOMEM;
 383                 INIT_LIST_HEAD(&fs_devices->devices);
 384                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 385                 list_add(&fs_devices->list, &fs_uuids);
 386                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 387                 fs_devices->latest_devid = devid;
 388                 fs_devices->latest_trans = found_transid;
 389                 mutex_init(&fs_devices->device_list_mutex);
 390                 device = NULL;
 391         } else {
 392                 device = __find_device(&fs_devices->devices, devid,
 393                                        disk_super->dev_item.uuid);
 394         }
 395         if (!device) {
 396                 if (fs_devices->opened)
 397                         return -EBUSY;
 398
 399                 device = kzalloc(sizeof(*device), GFP_NOFS);
 400                 if (!device) {
 401                         /* we can safely leave the fs_devices entry around */
 402                         return -ENOMEM;
 403                 }
 404                 device->devid = devid;
 405                 device->dev_stats_valid = 0;
 406                 device->work.func = pending_bios_fn;
 407                 memcpy(device->uuid, disk_super->dev_item.uuid,
 408                        BTRFS_UUID_SIZE);
 409                 spin_lock_init(&device->io_lock);
 410
 411                 name = rcu_string_strdup(path, GFP_NOFS);
 412                 if (!name) {
 413                         kfree(device);
 414                         return -ENOMEM;
 415                 }
 416                 rcu_assign_pointer(device->name, name);
 417                 INIT_LIST_HEAD(&device->dev_alloc_list);
 418
 419                 /* init readahead state */
 420                 spin_lock_init(&device->reada_lock);
 421                 device->reada_curr_zone = NULL;
 422                 atomic_set(&device->reada_in_flight, 0);
 423                 device->reada_next = 0;
 424                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 425                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 426
 427                 mutex_lock(&fs_devices->device_list_mutex);
 428                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 429                 mutex_unlock(&fs_devices->device_list_mutex);
 430
 431                 device->fs_devices = fs_devices;
 432                 fs_devices->num_devices++;
 433         } else if (!device->name || strcmp(device->name->str, path)) {
 434                 name = rcu_string_strdup(path, GFP_NOFS);
 435                 if (!name)
 436                         return -ENOMEM;
 437                 rcu_string_free(device->name);
 438                 rcu_assign_pointer(device->name, name);
 439                 if (device->missing) {
 440                         fs_devices->missing_devices--;
 441                         device->missing = 0;
 442                 }
 443         }
 444
 445         if (found_transid > fs_devices->latest_trans) {
 446                 fs_devices->latest_devid = devid;
 447                 fs_devices->latest_trans = found_transid;
 448         }
 449         *fs_devices_ret = fs_devices;
 450         return 0;
 451 }
 452
 453 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 454 {
 455         struct btrfs_fs_devices *fs_devices;
 456         struct btrfs_device *device;
 457         struct btrfs_device *orig_dev;
 458
 459         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 460         if (!fs_devices)
 461                 return ERR_PTR(-ENOMEM);
 462
 463         INIT_LIST_HEAD(&fs_devices->devices);
 464         INIT_LIST_HEAD(&fs_devices->alloc_list);
 465         INIT_LIST_HEAD(&fs_devices->list);
 466         mutex_init(&fs_devices->device_list_mutex);
 467         fs_devices->latest_devid = orig->latest_devid;
 468         fs_devices->latest_trans = orig->latest_trans;
 469         fs_devices->total_devices = orig->total_devices;
 470         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 471
 472         /* We have held the volume lock, it is safe to get the devices. */
 473         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 474                 struct rcu_string *name;
 475
 476                 device = kzalloc(sizeof(*device), GFP_NOFS);
 477                 if (!device)
 478                         goto error;
 479
 480                 /*
 481                  * This is ok to do without rcu read locked because we hold the
 482                  * uuid mutex so nothing we touch in here is going to disappear.
 483                  */
 484                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 485                 if (!name) {
 486                         kfree(device);
 487                         goto error;
 488                 }
 489                 rcu_assign_pointer(device->name, name);
 490
 491                 device->devid = orig_dev->devid;
 492                 device->work.func = pending_bios_fn;
 493                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 494                 spin_lock_init(&device->io_lock);
 495                 INIT_LIST_HEAD(&device->dev_list);
 496                 INIT_LIST_HEAD(&device->dev_alloc_list);
 497
 498                 list_add(&device->dev_list, &fs_devices->devices);
 499                 device->fs_devices = fs_devices;
 500                 fs_devices->num_devices++;
 501         }
 502         return fs_devices;
 503 error:
 504         free_fs_devices(fs_devices);
 505         return ERR_PTR(-ENOMEM);
 506 }
 507
 508 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 509 {
 510         struct btrfs_device *device, *next;
 511
 512         struct block_device *latest_bdev = NULL;
 513         u64 latest_devid = 0;
 514         u64 latest_transid = 0;
 515
 516         mutex_lock(&uuid_mutex);
 517 again:
 518         /* This is the initialized path, it is safe to release the devices. */
 519         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 520                 if (device->in_fs_metadata) {
 521                         if (!latest_transid ||
 522                             device->generation > latest_transid) {
 523                                 latest_devid = device->devid;
 524                                 latest_transid = device->generation;
 525                                 latest_bdev = device->bdev;
 526                         }
 527                         continue;
 528                 }
 529
 530                 if (device->bdev) {
 531                         blkdev_put(device->bdev, device->mode);
 532                         device->bdev = NULL;
 533                         fs_devices->open_devices--;
 534                 }
 535                 if (device->writeable) {
 536                         list_del_init(&device->dev_alloc_list);
 537                         device->writeable = 0;
 538                         fs_devices->rw_devices--;
 539                 }
 540                 list_del_init(&device->dev_list);
 541                 fs_devices->num_devices--;
 542                 rcu_string_free(device->name);
 543                 kfree(device);
 544         }
 545
 546         if (fs_devices->seed) {
 547                 fs_devices = fs_devices->seed;
 548                 goto again;
 549         }
 550
 551         fs_devices->latest_bdev = latest_bdev;
 552         fs_devices->latest_devid = latest_devid;
 553         fs_devices->latest_trans = latest_transid;
 554
 555         mutex_unlock(&uuid_mutex);
 556 }
 557
 558 static void __free_device(struct work_struct *work)
 559 {
 560         struct btrfs_device *device;
 561
 562         device = container_of(work, struct btrfs_device, rcu_work);
 563
 564         if (device->bdev)
 565                 blkdev_put(device->bdev, device->mode);
 566
 567         rcu_string_free(device->name);
 568         kfree(device);
 569 }
 570
 571 static void free_device(struct rcu_head *head)
 572 {
 573         struct btrfs_device *device;
 574
 575         device = container_of(head, struct btrfs_device, rcu);
 576
 577         INIT_WORK(&device->rcu_work, __free_device);
 578         schedule_work(&device->rcu_work);
 579 }
 580
 581 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 582 {
 583         struct btrfs_device *device;
 584
 585         if (--fs_devices->opened > 0)
 586                 return 0;
 587
 588         mutex_lock(&fs_devices->device_list_mutex);
 589         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 590                 struct btrfs_device *new_device;
 591                 struct rcu_string *name;
 592
 593                 if (device->bdev)
 594                         fs_devices->open_devices--;
 595
 596                 if (device->writeable) {
 597                         list_del_init(&device->dev_alloc_list);
 598                         fs_devices->rw_devices--;
 599                 }
 600
 601                 if (device->can_discard)
 602                         fs_devices->num_can_discard--;
 603
 604                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 605                 BUG_ON(!new_device); /* -ENOMEM */
 606                 memcpy(new_device, device, sizeof(*new_device));
 607
 608                 /* Safe because we are under uuid_mutex */
 609                 if (device->name) {
 610                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
 611                         BUG_ON(device->name && !name); /* -ENOMEM */
 612                         rcu_assign_pointer(new_device->name, name);
 613                 }
 614                 new_device->bdev = NULL;
 615                 new_device->writeable = 0;
 616                 new_device->in_fs_metadata = 0;
 617                 new_device->can_discard = 0;
 618                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 619
 620                 call_rcu(&device->rcu, free_device);
 621         }
 622         mutex_unlock(&fs_devices->device_list_mutex);
 623
 624         WARN_ON(fs_devices->open_devices);
 625         WARN_ON(fs_devices->rw_devices);
 626         fs_devices->opened = 0;
 627         fs_devices->seeding = 0;
 628
 629         return 0;
 630 }
 631
 632 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 633 {
 634         struct btrfs_fs_devices *seed_devices = NULL;
 635         int ret;
 636
 637         mutex_lock(&uuid_mutex);
 638         ret = __btrfs_close_devices(fs_devices);
 639         if (!fs_devices->opened) {
 640                 seed_devices = fs_devices->seed;
 641                 fs_devices->seed = NULL;
 642         }
 643         mutex_unlock(&uuid_mutex);
 644
 645         while (seed_devices) {
 646                 fs_devices = seed_devices;
 647                 seed_devices = fs_devices->seed;
 648                 __btrfs_close_devices(fs_devices);
 649                 free_fs_devices(fs_devices);
 650         }
 651         return ret;
 652 }
 653
 654 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 655                                 fmode_t flags, void *holder)
 656 {
 657         struct request_queue *q;
 658         struct block_device *bdev;
 659         struct list_head *head = &fs_devices->devices;
 660         struct btrfs_device *device;
 661         struct block_device *latest_bdev = NULL;
 662         struct buffer_head *bh;
 663         struct btrfs_super_block *disk_super;
 664         u64 latest_devid = 0;
 665         u64 latest_transid = 0;
 666         u64 devid;
 667         int seeding = 1;
 668         int ret = 0;
 669
 670         flags |= FMODE_EXCL;
 671
 672         list_for_each_entry(device, head, dev_list) {
 673                 if (device->bdev)
 674                         continue;
 675                 if (!device->name)
 676                         continue;
 677
 678                 ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 679                                             &bdev, &bh);
 680                 if (ret)
 681                         continue;
 682
 683                 disk_super = (struct btrfs_super_block *)bh->b_data;
 684                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 685                 if (devid != device->devid)
 686                         goto error_brelse;
 687
 688                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 689                            BTRFS_UUID_SIZE))
 690                         goto error_brelse;
 691
 692                 device->generation = btrfs_super_generation(disk_super);
 693                 if (!latest_transid || device->generation > latest_transid) {
 694                         latest_devid = devid;
 695                         latest_transid = device->generation;
 696                         latest_bdev = bdev;
 697                 }
 698
 699                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 700                         device->writeable = 0;
 701                 } else {
 702                         device->writeable = !bdev_read_only(bdev);
 703                         seeding = 0;
 704                 }
 705
 706                 q = bdev_get_queue(bdev);
 707                 if (blk_queue_discard(q)) {
 708                         device->can_discard = 1;
 709                         fs_devices->num_can_discard++;
 710                 }
 711
 712                 device->bdev = bdev;
 713                 device->in_fs_metadata = 0;
 714                 device->mode = flags;
 715
 716                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 717                         fs_devices->rotating = 1;
 718
 719                 fs_devices->open_devices++;
 720                 if (device->writeable) {
 721                         fs_devices->rw_devices++;
 722                         list_add(&device->dev_alloc_list,
 723                                  &fs_devices->alloc_list);
 724                 }
 725                 brelse(bh);
 726                 continue;
 727
 728 error_brelse:
 729                 brelse(bh);
 730                 blkdev_put(bdev, flags);
 731                 continue;
 732         }
 733         if (fs_devices->open_devices == 0) {
 734                 ret = -EINVAL;
 735                 goto out;
 736         }
 737         fs_devices->seeding = seeding;
 738         fs_devices->opened = 1;
 739         fs_devices->latest_bdev = latest_bdev;
 740         fs_devices->latest_devid = latest_devid;
 741         fs_devices->latest_trans = latest_transid;
 742         fs_devices->total_rw_bytes = 0;
 743 out:
 744         return ret;
 745 }
 746
 747 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 748                        fmode_t flags, void *holder)
 749 {
 750         int ret;
 751
 752         mutex_lock(&uuid_mutex);
 753         if (fs_devices->opened) {
 754                 fs_devices->opened++;
 755                 ret = 0;
 756         } else {
 757                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 758         }
 759         mutex_unlock(&uuid_mutex);
 760         return ret;
 761 }
 762
 763 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 764                           struct btrfs_fs_devices **fs_devices_ret)
 765 {
 766         struct btrfs_super_block *disk_super;
 767         struct block_device *bdev;
 768         struct buffer_head *bh;
 769         int ret;
 770         u64 devid;
 771         u64 transid;
 772         u64 total_devices;
 773
 774         flags |= FMODE_EXCL;
 775         mutex_lock(&uuid_mutex);
 776         ret = btrfs_get_bdev_and_sb(path, flags, holder, 0, &bdev, &bh);
 777         if (ret)
 778                 goto error;
 779         disk_super = (struct btrfs_super_block *)bh->b_data;
 780         devid = btrfs_stack_device_id(&disk_super->dev_item);
 781         transid = btrfs_super_generation(disk_super);
 782         total_devices = btrfs_super_num_devices(disk_super);
 783         if (disk_super->label[0]) {
 784                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
 785                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
 786                 printk(KERN_INFO "device label %s ", disk_super->label);
 787         } else {
 788                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 789         }
 790         printk(KERN_CONT "devid %llu transid %llu %s\n",
 791                (unsigned long long)devid, (unsigned long long)transid, path);
 792         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 793         if (!ret && fs_devices_ret)
 794                 (*fs_devices_ret)->total_devices = total_devices;
 795         brelse(bh);
 796         blkdev_put(bdev, flags);
 797 error:
 798         mutex_unlock(&uuid_mutex);
 799         return ret;
 800 }
 801
 802 /* helper to account the used device space in the range */
 803 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 804                                    u64 end, u64 *length)
 805 {
 806         struct btrfs_key key;
 807         struct btrfs_root *root = device->dev_root;
 808         struct btrfs_dev_extent *dev_extent;
 809         struct btrfs_path *path;
 810         u64 extent_end;
 811         int ret;
 812         int slot;
 813         struct extent_buffer *l;
 814
 815         *length = 0;
 816
 817         if (start >= device->total_bytes)
 818                 return 0;
 819
 820         path = btrfs_alloc_path();
 821         if (!path)
 822                 return -ENOMEM;
 823         path->reada = 2;
 824
 825         key.objectid = device->devid;
 826         key.offset = start;
 827         key.type = BTRFS_DEV_EXTENT_KEY;
 828
 829         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 830         if (ret < 0)
 831                 goto out;
 832         if (ret > 0) {
 833                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 834                 if (ret < 0)
 835                         goto out;
 836         }
 837
 838         while (1) {
 839                 l = path->nodes[0];
 840                 slot = path->slots[0];
 841                 if (slot >= btrfs_header_nritems(l)) {
 842                         ret = btrfs_next_leaf(root, path);
 843                         if (ret == 0)
 844                                 continue;
 845                         if (ret < 0)
 846                                 goto out;
 847
 848                         break;
 849                 }
 850                 btrfs_item_key_to_cpu(l, &key, slot);
 851
 852                 if (key.objectid < device->devid)
 853                         goto next;
 854
 855                 if (key.objectid > device->devid)
 856                         break;
 857
 858                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 859                         goto next;
 860
 861                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 862                 extent_end = key.offset + btrfs_dev_extent_length(l,
 863                                                                   dev_extent);
 864                 if (key.offset <= start && extent_end > end) {
 865                         *length = end - start + 1;
 866                         break;
 867                 } else if (key.offset <= start && extent_end > start)
 868                         *length += extent_end - start;
 869                 else if (key.offset > start && extent_end <= end)
 870                         *length += extent_end - key.offset;
 871                 else if (key.offset > start && key.offset <= end) {
 872                         *length += end - key.offset + 1;
 873                         break;
 874                 } else if (key.offset > end)
 875                         break;
 876
 877 next:
 878                 path->slots[0]++;
 879         }
 880         ret = 0;
 881 out:
 882         btrfs_free_path(path);
 883         return ret;
 884 }
 885
 886 /*
 887  * find_free_dev_extent - find free space in the specified device
 888  * @device:     the device which we search the free space in
 889  * @num_bytes:  the size of the free space that we need
 890  * @start:      store the start of the free space.
 891  * @len:        the size of the free space. that we find, or the size of the max
 892  *              free space if we don't find suitable free space
 893  *
 894  * this uses a pretty simple search, the expectation is that it is
 895  * called very infrequently and that a given device has a small number
 896  * of extents
 897  *
 898  * @start is used to store the start of the free space if we find. But if we
 899  * don't find suitable free space, it will be used to store the start position
 900  * of the max free space.
 901  *
 902  * @len is used to store the size of the free space that we find.
 903  * But if we don't find suitable free space, it is used to store the size of
 904  * the max free space.
 905  */
 906 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 907                          u64 *start, u64 *len)
 908 {
 909         struct btrfs_key key;
 910         struct btrfs_root *root = device->dev_root;
 911         struct btrfs_dev_extent *dev_extent;
 912         struct btrfs_path *path;
 913         u64 hole_size;
 914         u64 max_hole_start;
 915         u64 max_hole_size;
 916         u64 extent_end;
 917         u64 search_start;
 918         u64 search_end = device->total_bytes;
 919         int ret;
 920         int slot;
 921         struct extent_buffer *l;
 922
 923         /* FIXME use last free of some kind */
 924
 925         /* we don't want to overwrite the superblock on the drive,
 926          * so we make sure to start at an offset of at least 1MB
 927          */
 928         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 929
 930         max_hole_start = search_start;
 931         max_hole_size = 0;
 932         hole_size = 0;
 933
 934         if (search_start >= search_end) {
 935                 ret = -ENOSPC;
 936                 goto error;
 937         }
 938
 939         path = btrfs_alloc_path();
 940         if (!path) {
 941                 ret = -ENOMEM;
 942                 goto error;
 943         }
 944         path->reada = 2;
 945
 946         key.objectid = device->devid;
 947         key.offset = search_start;
 948         key.type = BTRFS_DEV_EXTENT_KEY;
 949
 950         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 951         if (ret < 0)
 952                 goto out;
 953         if (ret > 0) {
 954                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 955                 if (ret < 0)
 956                         goto out;
 957         }
 958
 959         while (1) {
 960                 l = path->nodes[0];
 961                 slot = path->slots[0];
 962                 if (slot >= btrfs_header_nritems(l)) {
 963                         ret = btrfs_next_leaf(root, path);
 964                         if (ret == 0)
 965                                 continue;
 966                         if (ret < 0)
 967                                 goto out;
 968
 969                         break;
 970                 }
 971                 btrfs_item_key_to_cpu(l, &key, slot);
 972
 973                 if (key.objectid < device->devid)
 974                         goto next;
 975
 976                 if (key.objectid > device->devid)
 977                         break;
 978
 979                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 980                         goto next;
 981
 982                 if (key.offset > search_start) {
 983                         hole_size = key.offset - search_start;
 984
 985                         if (hole_size > max_hole_size) {
 986                                 max_hole_start = search_start;
 987                                 max_hole_size = hole_size;
 988                         }
 989
 990                         /*
 991                          * If this free space is greater than which we need,
 992                          * it must be the max free space that we have found
 993                          * until now, so max_hole_start must point to the start
 994                          * of this free space and the length of this free space
 995                          * is stored in max_hole_size. Thus, we return
 996                          * max_hole_start and max_hole_size and go back to the
 997                          * caller.
 998                          */
 999                         if (hole_size >= num_bytes) {
1000                                 ret = 0;
1001                                 goto out;
1002                         }
1003                 }
1004
1005                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1006                 extent_end = key.offset + btrfs_dev_extent_length(l,
1007                                                                   dev_extent);
1008                 if (extent_end > search_start)
1009                         search_start = extent_end;
1010 next:
1011                 path->slots[0]++;
1012                 cond_resched();
1013         }
1014
1015         /*
1016          * At this point, search_start should be the end of
1017          * allocated dev extents, and when shrinking the device,
1018          * search_end may be smaller than search_start.
1019          */
1020         if (search_end > search_start)
1021                 hole_size = search_end - search_start;
1022
1023         if (hole_size > max_hole_size) {
1024                 max_hole_start = search_start;
1025                 max_hole_size = hole_size;
1026         }
1027
1028         /* See above. */
1029         if (hole_size < num_bytes)
1030                 ret = -ENOSPC;
1031         else
1032                 ret = 0;
1033
1034 out:
1035         btrfs_free_path(path);
1036 error:
1037         *start = max_hole_start;
1038         if (len)
1039                 *len = max_hole_size;
1040         return ret;
1041 }
1042
1043 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1044                           struct btrfs_device *device,
1045                           u64 start)
1046 {
1047         int ret;
1048         struct btrfs_path *path;
1049         struct btrfs_root *root = device->dev_root;
1050         struct btrfs_key key;
1051         struct btrfs_key found_key;
1052         struct extent_buffer *leaf = NULL;
1053         struct btrfs_dev_extent *extent = NULL;
1054
1055         path = btrfs_alloc_path();
1056         if (!path)
1057                 return -ENOMEM;
1058
1059         key.objectid = device->devid;
1060         key.offset = start;
1061         key.type = BTRFS_DEV_EXTENT_KEY;
1062 again:
1063         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1064         if (ret > 0) {
1065                 ret = btrfs_previous_item(root, path, key.objectid,
1066                                           BTRFS_DEV_EXTENT_KEY);
1067                 if (ret)
1068                         goto out;
1069                 leaf = path->nodes[0];
1070                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1071                 extent = btrfs_item_ptr(leaf, path->slots[0],
1072                                         struct btrfs_dev_extent);
1073                 BUG_ON(found_key.offset > start || found_key.offset +
1074                        btrfs_dev_extent_length(leaf, extent) < start);
1075                 key = found_key;
1076                 btrfs_release_path(path);
1077                 goto again;
1078         } else if (ret == 0) {
1079                 leaf = path->nodes[0];
1080                 extent = btrfs_item_ptr(leaf, path->slots[0],
1081                                         struct btrfs_dev_extent);
1082         } else {
1083                 btrfs_error(root->fs_info, ret, "Slot search failed");
1084                 goto out;
1085         }
1086
1087         if (device->bytes_used > 0) {
1088                 u64 len = btrfs_dev_extent_length(leaf, extent);
1089                 device->bytes_used -= len;
1090                 spin_lock(&root->fs_info->free_chunk_lock);
1091                 root->fs_info->free_chunk_space += len;
1092                 spin_unlock(&root->fs_info->free_chunk_lock);
1093         }
1094         ret = btrfs_del_item(trans, root, path);
1095         if (ret) {
1096                 btrfs_error(root->fs_info, ret,
1097                             "Failed to remove dev extent item");
1098         }
1099 out:
1100         btrfs_free_path(path);
1101         return ret;
1102 }
1103
1104 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1105                            struct btrfs_device *device,
1106                            u64 chunk_tree, u64 chunk_objectid,
1107                            u64 chunk_offset, u64 start, u64 num_bytes)
1108 {
1109         int ret;
1110         struct btrfs_path *path;
1111         struct btrfs_root *root = device->dev_root;
1112         struct btrfs_dev_extent *extent;
1113         struct extent_buffer *leaf;
1114         struct btrfs_key key;
1115
1116         WARN_ON(!device->in_fs_metadata);
1117         path = btrfs_alloc_path();
1118         if (!path)
1119                 return -ENOMEM;
1120
1121         key.objectid = device->devid;
1122         key.offset = start;
1123         key.type = BTRFS_DEV_EXTENT_KEY;
1124         ret = btrfs_insert_empty_item(trans, root, path, &key,
1125                                       sizeof(*extent));
1126         if (ret)
1127                 goto out;
1128
1129         leaf = path->nodes[0];
1130         extent = btrfs_item_ptr(leaf, path->slots[0],
1131                                 struct btrfs_dev_extent);
1132         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1133         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1134         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1135
1136         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1137                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1138                     BTRFS_UUID_SIZE);
1139
1140         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1141         btrfs_mark_buffer_dirty(leaf);
1142 out:
1143         btrfs_free_path(path);
1144         return ret;
1145 }
1146
1147 static noinline int find_next_chunk(struct btrfs_root *root,
1148                                     u64 objectid, u64 *offset)
1149 {
1150         struct btrfs_path *path;
1151         int ret;
1152         struct btrfs_key key;
1153         struct btrfs_chunk *chunk;
1154         struct btrfs_key found_key;
1155
1156         path = btrfs_alloc_path();
1157         if (!path)
1158                 return -ENOMEM;
1159
1160         key.objectid = objectid;
1161         key.offset = (u64)-1;
1162         key.type = BTRFS_CHUNK_ITEM_KEY;
1163
1164         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1165         if (ret < 0)
1166                 goto error;
1167
1168         BUG_ON(ret == 0); /* Corruption */
1169
1170         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1171         if (ret) {
1172                 *offset = 0;
1173         } else {
1174                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1175                                       path->slots[0]);
1176                 if (found_key.objectid != objectid)
1177                         *offset = 0;
1178                 else {
1179                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1180                                                struct btrfs_chunk);
1181                         *offset = found_key.offset +
1182                                 btrfs_chunk_length(path->nodes[0], chunk);
1183                 }
1184         }
1185         ret = 0;
1186 error:
1187         btrfs_free_path(path);
1188         return ret;
1189 }
1190
1191 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1192 {
1193         int ret;
1194         struct btrfs_key key;
1195         struct btrfs_key found_key;
1196         struct btrfs_path *path;
1197
1198         root = root->fs_info->chunk_root;
1199
1200         path = btrfs_alloc_path();
1201         if (!path)
1202                 return -ENOMEM;
1203
1204         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1205         key.type = BTRFS_DEV_ITEM_KEY;
1206         key.offset = (u64)-1;
1207
1208         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1209         if (ret < 0)
1210                 goto error;
1211
1212         BUG_ON(ret == 0); /* Corruption */
1213
1214         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1215                                   BTRFS_DEV_ITEM_KEY);
1216         if (ret) {
1217                 *objectid = 1;
1218         } else {
1219                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1220                                       path->slots[0]);
1221                 *objectid = found_key.offset + 1;
1222         }
1223         ret = 0;
1224 error:
1225         btrfs_free_path(path);
1226         return ret;
1227 }
1228
1229 /*
1230  * the device information is stored in the chunk root
1231  * the btrfs_device struct should be fully filled in
1232  */
1233 int btrfs_add_device(struct btrfs_trans_handle *trans,
1234                      struct btrfs_root *root,
1235                      struct btrfs_device *device)
1236 {
1237         int ret;
1238         struct btrfs_path *path;
1239         struct btrfs_dev_item *dev_item;
1240         struct extent_buffer *leaf;
1241         struct btrfs_key key;
1242         unsigned long ptr;
1243
1244         root = root->fs_info->chunk_root;
1245
1246         path = btrfs_alloc_path();
1247         if (!path)
1248                 return -ENOMEM;
1249
1250         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1251         key.type = BTRFS_DEV_ITEM_KEY;
1252         key.offset = device->devid;
1253
1254         ret = btrfs_insert_empty_item(trans, root, path, &key,
1255                                       sizeof(*dev_item));
1256         if (ret)
1257                 goto out;
1258
1259         leaf = path->nodes[0];
1260         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1261
1262         btrfs_set_device_id(leaf, dev_item, device->devid);
1263         btrfs_set_device_generation(leaf, dev_item, 0);
1264         btrfs_set_device_type(leaf, dev_item, device->type);
1265         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1266         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1267         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1268         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1269         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1270         btrfs_set_device_group(leaf, dev_item, 0);
1271         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1272         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1273         btrfs_set_device_start_offset(leaf, dev_item, 0);
1274
1275         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1276         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1277         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1278         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1279         btrfs_mark_buffer_dirty(leaf);
1280
1281         ret = 0;
1282 out:
1283         btrfs_free_path(path);
1284         return ret;
1285 }
1286
1287 static int btrfs_rm_dev_item(struct btrfs_root *root,
1288                              struct btrfs_device *device)
1289 {
1290         int ret;
1291         struct btrfs_path *path;
1292         struct btrfs_key key;
1293         struct btrfs_trans_handle *trans;
1294
1295         root = root->fs_info->chunk_root;
1296
1297         path = btrfs_alloc_path();
1298         if (!path)
1299                 return -ENOMEM;
1300
1301         trans = btrfs_start_transaction(root, 0);
1302         if (IS_ERR(trans)) {
1303                 btrfs_free_path(path);
1304                 return PTR_ERR(trans);
1305         }
1306         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1307         key.type = BTRFS_DEV_ITEM_KEY;
1308         key.offset = device->devid;
1309         lock_chunks(root);
1310
1311         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1312         if (ret < 0)
1313                 goto out;
1314
1315         if (ret > 0) {
1316                 ret = -ENOENT;
1317                 goto out;
1318         }
1319
1320         ret = btrfs_del_item(trans, root, path);
1321         if (ret)
1322                 goto out;
1323 out:
1324         btrfs_free_path(path);
1325         unlock_chunks(root);
1326         btrfs_commit_transaction(trans, root);
1327         return ret;
1328 }
1329
1330 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1331 {
1332         struct btrfs_device *device;
1333         struct btrfs_device *next_device;
1334         struct block_device *bdev;
1335         struct buffer_head *bh = NULL;
1336         struct btrfs_super_block *disk_super;
1337         struct btrfs_fs_devices *cur_devices;
1338         u64 all_avail;
1339         u64 devid;
1340         u64 num_devices;
1341         u8 *dev_uuid;
1342         int ret = 0;
1343         bool clear_super = false;
1344
1345         mutex_lock(&uuid_mutex);
1346
1347         all_avail = root->fs_info->avail_data_alloc_bits |
1348                 root->fs_info->avail_system_alloc_bits |
1349                 root->fs_info->avail_metadata_alloc_bits;
1350
1351         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1352             root->fs_info->fs_devices->num_devices <= 4) {
1353                 printk(KERN_ERR "btrfs: unable to go below four devices "
1354                        "on raid10\n");
1355                 ret = -EINVAL;
1356                 goto out;
1357         }
1358
1359         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1360             root->fs_info->fs_devices->num_devices <= 2) {
1361                 printk(KERN_ERR "btrfs: unable to go below two "
1362                        "devices on raid1\n");
1363                 ret = -EINVAL;
1364                 goto out;
1365         }
1366
1367         if (strcmp(device_path, "missing") == 0) {
1368                 struct list_head *devices;
1369                 struct btrfs_device *tmp;
1370
1371                 device = NULL;
1372                 devices = &root->fs_info->fs_devices->devices;
1373                 /*
1374                  * It is safe to read the devices since the volume_mutex
1375                  * is held.
1376                  */
1377                 list_for_each_entry(tmp, devices, dev_list) {
1378                         if (tmp->in_fs_metadata && !tmp->bdev) {
1379                                 device = tmp;
1380                                 break;
1381                         }
1382                 }
1383                 bdev = NULL;
1384                 bh = NULL;
1385                 disk_super = NULL;
1386                 if (!device) {
1387                         printk(KERN_ERR "btrfs: no missing devices found to "
1388                                "remove\n");
1389                         goto out;
1390                 }
1391         } else {
1392                 ret = btrfs_get_bdev_and_sb(device_path,
1393                                             FMODE_READ | FMODE_EXCL,
1394                                             root->fs_info->bdev_holder, 0,
1395                                             &bdev, &bh);
1396                 if (ret)
1397                         goto out;
1398                 disk_super = (struct btrfs_super_block *)bh->b_data;
1399                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1400                 dev_uuid = disk_super->dev_item.uuid;
1401                 device = btrfs_find_device(root, devid, dev_uuid,
1402                                            disk_super->fsid);
1403                 if (!device) {
1404                         ret = -ENOENT;
1405                         goto error_brelse;
1406                 }
1407         }
1408
1409         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1410                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1411                        "device\n");
1412                 ret = -EINVAL;
1413                 goto error_brelse;
1414         }
1415
1416         if (device->writeable) {
1417                 lock_chunks(root);
1418                 list_del_init(&device->dev_alloc_list);
1419                 unlock_chunks(root);
1420                 root->fs_info->fs_devices->rw_devices--;
1421                 clear_super = true;
1422         }
1423
1424         ret = btrfs_shrink_device(device, 0);
1425         if (ret)
1426                 goto error_undo;
1427
1428         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1429         if (ret)
1430                 goto error_undo;
1431
1432         spin_lock(&root->fs_info->free_chunk_lock);
1433         root->fs_info->free_chunk_space = device->total_bytes -
1434                 device->bytes_used;
1435         spin_unlock(&root->fs_info->free_chunk_lock);
1436
1437         device->in_fs_metadata = 0;
1438         btrfs_scrub_cancel_dev(root, device);
1439
1440         /*
1441          * the device list mutex makes sure that we don't change
1442          * the device list while someone else is writing out all
1443          * the device supers.
1444          */
1445
1446         cur_devices = device->fs_devices;
1447         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1448         list_del_rcu(&device->dev_list);
1449
1450         device->fs_devices->num_devices--;
1451         device->fs_devices->total_devices--;
1452
1453         if (device->missing)
1454                 root->fs_info->fs_devices->missing_devices--;
1455
1456         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1457                                  struct btrfs_device, dev_list);
1458         if (device->bdev == root->fs_info->sb->s_bdev)
1459                 root->fs_info->sb->s_bdev = next_device->bdev;
1460         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1461                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1462
1463         if (device->bdev)
1464                 device->fs_devices->open_devices--;
1465
1466         call_rcu(&device->rcu, free_device);
1467         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1468
1469         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1470         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1471
1472         if (cur_devices->open_devices == 0) {
1473                 struct btrfs_fs_devices *fs_devices;
1474                 fs_devices = root->fs_info->fs_devices;
1475                 while (fs_devices) {
1476                         if (fs_devices->seed == cur_devices)
1477                                 break;
1478                         fs_devices = fs_devices->seed;
1479                 }
1480                 fs_devices->seed = cur_devices->seed;
1481                 cur_devices->seed = NULL;
1482                 lock_chunks(root);
1483                 __btrfs_close_devices(cur_devices);
1484                 unlock_chunks(root);
1485                 free_fs_devices(cur_devices);
1486         }
1487
1488         root->fs_info->num_tolerated_disk_barrier_failures =
1489                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1490
1491         /*
1492          * at this point, the device is zero sized.  We want to
1493          * remove it from the devices list and zero out the old super
1494          */
1495         if (clear_super) {
1496                 /* make sure this device isn't detected as part of
1497                  * the FS anymore
1498                  */
1499                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1500                 set_buffer_dirty(bh);
1501                 sync_dirty_buffer(bh);
1502         }
1503
1504         ret = 0;
1505
1506 error_brelse:
1507         brelse(bh);
1508 error_close:
1509         if (bdev)
1510                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1511 out:
1512         mutex_unlock(&uuid_mutex);
1513         return ret;
1514 error_undo:
1515         if (device->writeable) {
1516                 lock_chunks(root);
1517                 list_add(&device->dev_alloc_list,
1518                          &root->fs_info->fs_devices->alloc_list);
1519                 unlock_chunks(root);
1520                 root->fs_info->fs_devices->rw_devices++;
1521         }
1522         goto error_brelse;
1523 }
1524
1525 int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1526                               struct btrfs_device **device)
1527 {
1528         int ret = 0;
1529         struct btrfs_super_block *disk_super;
1530         u64 devid;
1531         u8 *dev_uuid;
1532         struct block_device *bdev;
1533         struct buffer_head *bh;
1534
1535         *device = NULL;
1536         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1537                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1538         if (ret)
1539                 return ret;
1540         disk_super = (struct btrfs_super_block *)bh->b_data;
1541         devid = btrfs_stack_device_id(&disk_super->dev_item);
1542         dev_uuid = disk_super->dev_item.uuid;
1543         *device = btrfs_find_device(root, devid, dev_uuid,
1544                                     disk_super->fsid);
1545         brelse(bh);
1546         if (!*device)
1547                 ret = -ENOENT;
1548         blkdev_put(bdev, FMODE_READ);
1549         return ret;
1550 }
1551
1552 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1553                                          char *device_path,
1554                                          struct btrfs_device **device)
1555 {
1556         *device = NULL;
1557         if (strcmp(device_path, "missing") == 0) {
1558                 struct list_head *devices;
1559                 struct btrfs_device *tmp;
1560
1561                 devices = &root->fs_info->fs_devices->devices;
1562                 /*
1563                  * It is safe to read the devices since the volume_mutex
1564                  * is held by the caller.
1565                  */
1566                 list_for_each_entry(tmp, devices, dev_list) {
1567                         if (tmp->in_fs_metadata && !tmp->bdev) {
1568                                 *device = tmp;
1569                                 break;
1570                         }
1571                 }
1572
1573                 if (!*device) {
1574                         pr_err("btrfs: no missing device found\n");
1575                         return -ENOENT;
1576                 }
1577
1578                 return 0;
1579         } else {
1580                 return btrfs_find_device_by_path(root, device_path, device);
1581         }
1582 }
1583
1584 /*
1585  * does all the dirty work required for changing file system's UUID.
1586  */
1587 static int btrfs_prepare_sprout(struct btrfs_root *root)
1588 {
1589         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1590         struct btrfs_fs_devices *old_devices;
1591         struct btrfs_fs_devices *seed_devices;
1592         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1593         struct btrfs_device *device;
1594         u64 super_flags;
1595
1596         BUG_ON(!mutex_is_locked(&uuid_mutex));
1597         if (!fs_devices->seeding)
1598                 return -EINVAL;
1599
1600         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1601         if (!seed_devices)
1602                 return -ENOMEM;
1603
1604         old_devices = clone_fs_devices(fs_devices);
1605         if (IS_ERR(old_devices)) {
1606                 kfree(seed_devices);
1607                 return PTR_ERR(old_devices);
1608         }
1609
1610         list_add(&old_devices->list, &fs_uuids);
1611
1612         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1613         seed_devices->opened = 1;
1614         INIT_LIST_HEAD(&seed_devices->devices);
1615         INIT_LIST_HEAD(&seed_devices->alloc_list);
1616         mutex_init(&seed_devices->device_list_mutex);
1617
1618         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1619         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1620                               synchronize_rcu);
1621         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1622
1623         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1624         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1625                 device->fs_devices = seed_devices;
1626         }
1627
1628         fs_devices->seeding = 0;
1629         fs_devices->num_devices = 0;
1630         fs_devices->open_devices = 0;
1631         fs_devices->total_devices = 0;
1632         fs_devices->seed = seed_devices;
1633
1634         generate_random_uuid(fs_devices->fsid);
1635         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1636         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1637         super_flags = btrfs_super_flags(disk_super) &
1638                       ~BTRFS_SUPER_FLAG_SEEDING;
1639         btrfs_set_super_flags(disk_super, super_flags);
1640
1641         return 0;
1642 }
1643
1644 /*
1645  * strore the expected generation for seed devices in device items.
1646  */
1647 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1648                                struct btrfs_root *root)
1649 {
1650         struct btrfs_path *path;
1651         struct extent_buffer *leaf;
1652         struct btrfs_dev_item *dev_item;
1653         struct btrfs_device *device;
1654         struct btrfs_key key;
1655         u8 fs_uuid[BTRFS_UUID_SIZE];
1656         u8 dev_uuid[BTRFS_UUID_SIZE];
1657         u64 devid;
1658         int ret;
1659
1660         path = btrfs_alloc_path();
1661         if (!path)
1662                 return -ENOMEM;
1663
1664         root = root->fs_info->chunk_root;
1665         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1666         key.offset = 0;
1667         key.type = BTRFS_DEV_ITEM_KEY;
1668
1669         while (1) {
1670                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1671                 if (ret < 0)
1672                         goto error;
1673
1674                 leaf = path->nodes[0];
1675 next_slot:
1676                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1677                         ret = btrfs_next_leaf(root, path);
1678                         if (ret > 0)
1679                                 break;
1680                         if (ret < 0)
1681                                 goto error;
1682                         leaf = path->nodes[0];
1683                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1684                         btrfs_release_path(path);
1685                         continue;
1686                 }
1687
1688                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1689                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1690                     key.type != BTRFS_DEV_ITEM_KEY)
1691                         break;
1692
1693                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1694                                           struct btrfs_dev_item);
1695                 devid = btrfs_device_id(leaf, dev_item);
1696                 read_extent_buffer(leaf, dev_uuid,
1697                                    (unsigned long)btrfs_device_uuid(dev_item),
1698                                    BTRFS_UUID_SIZE);
1699                 read_extent_buffer(leaf, fs_uuid,
1700                                    (unsigned long)btrfs_device_fsid(dev_item),
1701                                    BTRFS_UUID_SIZE);
1702                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1703                 BUG_ON(!device); /* Logic error */
1704
1705                 if (device->fs_devices->seeding) {
1706                         btrfs_set_device_generation(leaf, dev_item,
1707                                                     device->generation);
1708                         btrfs_mark_buffer_dirty(leaf);
1709                 }
1710
1711                 path->slots[0]++;
1712                 goto next_slot;
1713         }
1714         ret = 0;
1715 error:
1716         btrfs_free_path(path);
1717         return ret;
1718 }
1719
1720 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1721 {
1722         struct request_queue *q;
1723         struct btrfs_trans_handle *trans;
1724         struct btrfs_device *device;
1725         struct block_device *bdev;
1726         struct list_head *devices;
1727         struct super_block *sb = root->fs_info->sb;
1728         struct rcu_string *name;
1729         u64 total_bytes;
1730         int seeding_dev = 0;
1731         int ret = 0;
1732
1733         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1734                 return -EROFS;
1735
1736         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1737                                   root->fs_info->bdev_holder);
1738         if (IS_ERR(bdev))
1739                 return PTR_ERR(bdev);
1740
1741         if (root->fs_info->fs_devices->seeding) {
1742                 seeding_dev = 1;
1743                 down_write(&sb->s_umount);
1744                 mutex_lock(&uuid_mutex);
1745         }
1746
1747         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1748
1749         devices = &root->fs_info->fs_devices->devices;
1750
1751         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1752         list_for_each_entry(device, devices, dev_list) {
1753                 if (device->bdev == bdev) {
1754                         ret = -EEXIST;
1755                         mutex_unlock(
1756                                 &root->fs_info->fs_devices->device_list_mutex);
1757                         goto error;
1758                 }
1759         }
1760         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1761
1762         device = kzalloc(sizeof(*device), GFP_NOFS);
1763         if (!device) {
1764                 /* we can safely leave the fs_devices entry around */
1765                 ret = -ENOMEM;
1766                 goto error;
1767         }
1768
1769         name = rcu_string_strdup(device_path, GFP_NOFS);
1770         if (!name) {
1771                 kfree(device);
1772                 ret = -ENOMEM;
1773                 goto error;
1774         }
1775         rcu_assign_pointer(device->name, name);
1776
1777         ret = find_next_devid(root, &device->devid);
1778         if (ret) {
1779                 rcu_string_free(device->name);
1780                 kfree(device);
1781                 goto error;
1782         }
1783
1784         trans = btrfs_start_transaction(root, 0);
1785         if (IS_ERR(trans)) {
1786                 rcu_string_free(device->name);
1787                 kfree(device);
1788                 ret = PTR_ERR(trans);
1789                 goto error;
1790         }
1791
1792         lock_chunks(root);
1793
1794         q = bdev_get_queue(bdev);
1795         if (blk_queue_discard(q))
1796                 device->can_discard = 1;
1797         device->writeable = 1;
1798         device->work.func = pending_bios_fn;
1799         generate_random_uuid(device->uuid);
1800         spin_lock_init(&device->io_lock);
1801         device->generation = trans->transid;
1802         device->io_width = root->sectorsize;
1803         device->io_align = root->sectorsize;
1804         device->sector_size = root->sectorsize;
1805         device->total_bytes = i_size_read(bdev->bd_inode);
1806         device->disk_total_bytes = device->total_bytes;
1807         device->dev_root = root->fs_info->dev_root;
1808         device->bdev = bdev;
1809         device->in_fs_metadata = 1;
1810         device->mode = FMODE_EXCL;
1811         set_blocksize(device->bdev, 4096);
1812
1813         if (seeding_dev) {
1814                 sb->s_flags &= ~MS_RDONLY;
1815                 ret = btrfs_prepare_sprout(root);
1816                 BUG_ON(ret); /* -ENOMEM */
1817         }
1818
1819         device->fs_devices = root->fs_info->fs_devices;
1820
1821         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1822         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1823         list_add(&device->dev_alloc_list,
1824                  &root->fs_info->fs_devices->alloc_list);
1825         root->fs_info->fs_devices->num_devices++;
1826         root->fs_info->fs_devices->open_devices++;
1827         root->fs_info->fs_devices->rw_devices++;
1828         root->fs_info->fs_devices->total_devices++;
1829         if (device->can_discard)
1830                 root->fs_info->fs_devices->num_can_discard++;
1831         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1832
1833         spin_lock(&root->fs_info->free_chunk_lock);
1834         root->fs_info->free_chunk_space += device->total_bytes;
1835         spin_unlock(&root->fs_info->free_chunk_lock);
1836
1837         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1838                 root->fs_info->fs_devices->rotating = 1;
1839
1840         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1841         btrfs_set_super_total_bytes(root->fs_info->super_copy,
1842                                     total_bytes + device->total_bytes);
1843
1844         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1845         btrfs_set_super_num_devices(root->fs_info->super_copy,
1846                                     total_bytes + 1);
1847         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1848
1849         if (seeding_dev) {
1850                 ret = init_first_rw_device(trans, root, device);
1851                 if (ret) {
1852                         btrfs_abort_transaction(trans, root, ret);
1853                         goto error_trans;
1854                 }
1855                 ret = btrfs_finish_sprout(trans, root);
1856                 if (ret) {
1857                         btrfs_abort_transaction(trans, root, ret);
1858                         goto error_trans;
1859                 }
1860         } else {
1861                 ret = btrfs_add_device(trans, root, device);
1862                 if (ret) {
1863                         btrfs_abort_transaction(trans, root, ret);
1864                         goto error_trans;
1865                 }
1866         }
1867
1868         /*
1869          * we've got more storage, clear any full flags on the space
1870          * infos
1871          */
1872         btrfs_clear_space_info_full(root->fs_info);
1873
1874         unlock_chunks(root);
1875         root->fs_info->num_tolerated_disk_barrier_failures =
1876                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1877         ret = btrfs_commit_transaction(trans, root);
1878
1879         if (seeding_dev) {
1880                 mutex_unlock(&uuid_mutex);
1881                 up_write(&sb->s_umount);
1882
1883                 if (ret) /* transaction commit */
1884                         return ret;
1885
1886                 ret = btrfs_relocate_sys_chunks(root);
1887                 if (ret < 0)
1888                         btrfs_error(root->fs_info, ret,
1889                                     "Failed to relocate sys chunks after "
1890                                     "device initialization. This can be fixed "
1891                                     "using the \"btrfs balance\" command.");
1892                 trans = btrfs_attach_transaction(root);
1893                 if (IS_ERR(trans)) {
1894                         if (PTR_ERR(trans) == -ENOENT)
1895                                 return 0;
1896                         return PTR_ERR(trans);
1897                 }
1898                 ret = btrfs_commit_transaction(trans, root);
1899         }
1900
1901         return ret;
1902
1903 error_trans:
1904         unlock_chunks(root);
1905         btrfs_end_transaction(trans, root);
1906         rcu_string_free(device->name);
1907         kfree(device);
1908 error:
1909         blkdev_put(bdev, FMODE_EXCL);
1910         if (seeding_dev) {
1911                 mutex_unlock(&uuid_mutex);
1912                 up_write(&sb->s_umount);
1913         }
1914         return ret;
1915 }
1916
1917 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1918                                         struct btrfs_device *device)
1919 {
1920         int ret;
1921         struct btrfs_path *path;
1922         struct btrfs_root *root;
1923         struct btrfs_dev_item *dev_item;
1924         struct extent_buffer *leaf;
1925         struct btrfs_key key;
1926
1927         root = device->dev_root->fs_info->chunk_root;
1928
1929         path = btrfs_alloc_path();
1930         if (!path)
1931                 return -ENOMEM;
1932
1933         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1934         key.type = BTRFS_DEV_ITEM_KEY;
1935         key.offset = device->devid;
1936
1937         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1938         if (ret < 0)
1939                 goto out;
1940
1941         if (ret > 0) {
1942                 ret = -ENOENT;
1943                 goto out;
1944         }
1945
1946         leaf = path->nodes[0];
1947         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1948
1949         btrfs_set_device_id(leaf, dev_item, device->devid);
1950         btrfs_set_device_type(leaf, dev_item, device->type);
1951         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1952         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1953         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1954         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1955         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1956         btrfs_mark_buffer_dirty(leaf);
1957
1958 out:
1959         btrfs_free_path(path);
1960         return ret;
1961 }
1962
1963 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1964                       struct btrfs_device *device, u64 new_size)
1965 {
1966         struct btrfs_super_block *super_copy =
1967                 device->dev_root->fs_info->super_copy;
1968         u64 old_total = btrfs_super_total_bytes(super_copy);
1969         u64 diff = new_size - device->total_bytes;
1970
1971         if (!device->writeable)
1972                 return -EACCES;
1973         if (new_size <= device->total_bytes)
1974                 return -EINVAL;
1975
1976         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1977         device->fs_devices->total_rw_bytes += diff;
1978
1979         device->total_bytes = new_size;
1980         device->disk_total_bytes = new_size;
1981         btrfs_clear_space_info_full(device->dev_root->fs_info);
1982
1983         return btrfs_update_device(trans, device);
1984 }
1985
1986 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1987                       struct btrfs_device *device, u64 new_size)
1988 {
1989         int ret;
1990         lock_chunks(device->dev_root);
1991         ret = __btrfs_grow_device(trans, device, new_size);
1992         unlock_chunks(device->dev_root);
1993         return ret;
1994 }
1995
1996 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1997                             struct btrfs_root *root,
1998                             u64 chunk_tree, u64 chunk_objectid,
1999                             u64 chunk_offset)
2000 {
2001         int ret;
2002         struct btrfs_path *path;
2003         struct btrfs_key key;
2004
2005         root = root->fs_info->chunk_root;
2006         path = btrfs_alloc_path();
2007         if (!path)
2008                 return -ENOMEM;
2009
2010         key.objectid = chunk_objectid;
2011         key.offset = chunk_offset;
2012         key.type = BTRFS_CHUNK_ITEM_KEY;
2013
2014         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2015         if (ret < 0)
2016                 goto out;
2017         else if (ret > 0) { /* Logic error or corruption */
2018                 btrfs_error(root->fs_info, -ENOENT,
2019                             "Failed lookup while freeing chunk.");
2020                 ret = -ENOENT;
2021                 goto out;
2022         }
2023
2024         ret = btrfs_del_item(trans, root, path);
2025         if (ret < 0)
2026                 btrfs_error(root->fs_info, ret,
2027                             "Failed to delete chunk item.");
2028 out:
2029         btrfs_free_path(path);
2030         return ret;
2031 }
2032
2033 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2034                         chunk_offset)
2035 {
2036         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2037         struct btrfs_disk_key *disk_key;
2038         struct btrfs_chunk *chunk;
2039         u8 *ptr;
2040         int ret = 0;
2041         u32 num_stripes;
2042         u32 array_size;
2043         u32 len = 0;
2044         u32 cur;
2045         struct btrfs_key key;
2046
2047         array_size = btrfs_super_sys_array_size(super_copy);
2048
2049         ptr = super_copy->sys_chunk_array;
2050         cur = 0;
2051
2052         while (cur < array_size) {
2053                 disk_key = (struct btrfs_disk_key *)ptr;
2054                 btrfs_disk_key_to_cpu(&key, disk_key);
2055
2056                 len = sizeof(*disk_key);
2057
2058                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2059                         chunk = (struct btrfs_chunk *)(ptr + len);
2060                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2061                         len += btrfs_chunk_item_size(num_stripes);
2062                 } else {
2063                         ret = -EIO;
2064                         break;
2065                 }
2066                 if (key.objectid == chunk_objectid &&
2067                     key.offset == chunk_offset) {
2068                         memmove(ptr, ptr + len, array_size - (cur + len));
2069                         array_size -= len;
2070                         btrfs_set_super_sys_array_size(super_copy, array_size);
2071                 } else {
2072                         ptr += len;
2073                         cur += len;
2074                 }
2075         }
2076         return ret;
2077 }
2078
2079 static int btrfs_relocate_chunk(struct btrfs_root *root,
2080                          u64 chunk_tree, u64 chunk_objectid,
2081                          u64 chunk_offset)
2082 {
2083         struct extent_map_tree *em_tree;
2084         struct btrfs_root *extent_root;
2085         struct btrfs_trans_handle *trans;
2086         struct extent_map *em;
2087         struct map_lookup *map;
2088         int ret;
2089         int i;
2090
2091         root = root->fs_info->chunk_root;
2092         extent_root = root->fs_info->extent_root;
2093         em_tree = &root->fs_info->mapping_tree.map_tree;
2094
2095         ret = btrfs_can_relocate(extent_root, chunk_offset);
2096         if (ret)
2097                 return -ENOSPC;
2098
2099         /* step one, relocate all the extents inside this chunk */
2100         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2101         if (ret)
2102                 return ret;
2103
2104         trans = btrfs_start_transaction(root, 0);
2105         BUG_ON(IS_ERR(trans));
2106
2107         lock_chunks(root);
2108
2109         /*
2110          * step two, delete the device extents and the
2111          * chunk tree entries
2112          */
2113         read_lock(&em_tree->lock);
2114         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2115         read_unlock(&em_tree->lock);
2116
2117         BUG_ON(!em || em->start > chunk_offset ||
2118                em->start + em->len < chunk_offset);
2119         map = (struct map_lookup *)em->bdev;
2120
2121         for (i = 0; i < map->num_stripes; i++) {
2122                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2123                                             map->stripes[i].physical);
2124                 BUG_ON(ret);
2125
2126                 if (map->stripes[i].dev) {
2127                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2128                         BUG_ON(ret);
2129                 }
2130         }
2131         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2132                                chunk_offset);
2133
2134         BUG_ON(ret);
2135
2136         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2137
2138         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2139                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2140                 BUG_ON(ret);
2141         }
2142
2143         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2144         BUG_ON(ret);
2145
2146         write_lock(&em_tree->lock);
2147         remove_extent_mapping(em_tree, em);
2148         write_unlock(&em_tree->lock);
2149
2150         kfree(map);
2151         em->bdev = NULL;
2152
2153         /* once for the tree */
2154         free_extent_map(em);
2155         /* once for us */
2156         free_extent_map(em);
2157
2158         unlock_chunks(root);
2159         btrfs_end_transaction(trans, root);
2160         return 0;
2161 }
2162
2163 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2164 {
2165         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2166         struct btrfs_path *path;
2167         struct extent_buffer *leaf;
2168         struct btrfs_chunk *chunk;
2169         struct btrfs_key key;
2170         struct btrfs_key found_key;
2171         u64 chunk_tree = chunk_root->root_key.objectid;
2172         u64 chunk_type;
2173         bool retried = false;
2174         int failed = 0;
2175         int ret;
2176
2177         path = btrfs_alloc_path();
2178         if (!path)
2179                 return -ENOMEM;
2180
2181 again:
2182         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2183         key.offset = (u64)-1;
2184         key.type = BTRFS_CHUNK_ITEM_KEY;
2185
2186         while (1) {
2187                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2188                 if (ret < 0)
2189                         goto error;
2190                 BUG_ON(ret == 0); /* Corruption */
2191
2192                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2193                                           key.type);
2194                 if (ret < 0)
2195                         goto error;
2196                 if (ret > 0)
2197                         break;
2198
2199                 leaf = path->nodes[0];
2200                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2201
2202                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2203                                        struct btrfs_chunk);
2204                 chunk_type = btrfs_chunk_type(leaf, chunk);
2205                 btrfs_release_path(path);
2206
2207                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2208                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2209                                                    found_key.objectid,
2210                                                    found_key.offset);
2211                         if (ret == -ENOSPC)
2212                                 failed++;
2213                         else if (ret)
2214                                 BUG();
2215                 }
2216
2217                 if (found_key.offset == 0)
2218                         break;
2219                 key.offset = found_key.offset - 1;
2220         }
2221         ret = 0;
2222         if (failed && !retried) {
2223                 failed = 0;
2224                 retried = true;
2225                 goto again;
2226         } else if (failed && retried) {
2227                 WARN_ON(1);
2228                 ret = -ENOSPC;
2229         }
2230 error:
2231         btrfs_free_path(path);
2232         return ret;
2233 }
2234
2235 static int insert_balance_item(struct btrfs_root *root,
2236                                struct btrfs_balance_control *bctl)
2237 {
2238         struct btrfs_trans_handle *trans;
2239         struct btrfs_balance_item *item;
2240         struct btrfs_disk_balance_args disk_bargs;
2241         struct btrfs_path *path;
2242         struct extent_buffer *leaf;
2243         struct btrfs_key key;
2244         int ret, err;
2245
2246         path = btrfs_alloc_path();
2247         if (!path)
2248                 return -ENOMEM;
2249
2250         trans = btrfs_start_transaction(root, 0);
2251         if (IS_ERR(trans)) {
2252                 btrfs_free_path(path);
2253                 return PTR_ERR(trans);
2254         }
2255
2256         key.objectid = BTRFS_BALANCE_OBJECTID;
2257         key.type = BTRFS_BALANCE_ITEM_KEY;
2258         key.offset = 0;
2259
2260         ret = btrfs_insert_empty_item(trans, root, path, &key,
2261                                       sizeof(*item));
2262         if (ret)
2263                 goto out;
2264
2265         leaf = path->nodes[0];
2266         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2267
2268         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2269
2270         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2271         btrfs_set_balance_data(leaf, item, &disk_bargs);
2272         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2273         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2274         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2275         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2276
2277         btrfs_set_balance_flags(leaf, item, bctl->flags);
2278
2279         btrfs_mark_buffer_dirty(leaf);
2280 out:
2281         btrfs_free_path(path);
2282         err = btrfs_commit_transaction(trans, root);
2283         if (err && !ret)
2284                 ret = err;
2285         return ret;
2286 }
2287
2288 static int del_balance_item(struct btrfs_root *root)
2289 {
2290         struct btrfs_trans_handle *trans;
2291         struct btrfs_path *path;
2292         struct btrfs_key key;
2293         int ret, err;
2294
2295         path = btrfs_alloc_path();
2296         if (!path)
2297                 return -ENOMEM;
2298
2299         trans = btrfs_start_transaction(root, 0);
2300         if (IS_ERR(trans)) {
2301                 btrfs_free_path(path);
2302                 return PTR_ERR(trans);
2303         }
2304
2305         key.objectid = BTRFS_BALANCE_OBJECTID;
2306         key.type = BTRFS_BALANCE_ITEM_KEY;
2307         key.offset = 0;
2308
2309         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2310         if (ret < 0)
2311                 goto out;
2312         if (ret > 0) {
2313                 ret = -ENOENT;
2314                 goto out;
2315         }
2316
2317         ret = btrfs_del_item(trans, root, path);
2318 out:
2319         btrfs_free_path(path);
2320         err = btrfs_commit_transaction(trans, root);
2321         if (err && !ret)
2322                 ret = err;
2323         return ret;
2324 }
2325
2326 /*
2327  * This is a heuristic used to reduce the number of chunks balanced on
2328  * resume after balance was interrupted.
2329  */
2330 static void update_balance_args(struct btrfs_balance_control *bctl)
2331 {
2332         /*
2333          * Turn on soft mode for chunk types that were being converted.
2334          */
2335         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2336                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2337         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2338                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2339         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2340                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2341
2342         /*
2343          * Turn on usage filter if is not already used.  The idea is
2344          * that chunks that we have already balanced should be
2345          * reasonably full.  Don't do it for chunks that are being
2346          * converted - that will keep us from relocating unconverted
2347          * (albeit full) chunks.
2348          */
2349         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2350             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2351                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2352                 bctl->data.usage = 90;
2353         }
2354         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2355             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2356                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2357                 bctl->sys.usage = 90;
2358         }
2359         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2360             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2361                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2362                 bctl->meta.usage = 90;
2363         }
2364 }
2365
2366 /*
2367  * Should be called with both balance and volume mutexes held to
2368  * serialize other volume operations (add_dev/rm_dev/resize) with
2369  * restriper.  Same goes for unset_balance_control.
2370  */
2371 static void set_balance_control(struct btrfs_balance_control *bctl)
2372 {
2373         struct btrfs_fs_info *fs_info = bctl->fs_info;
2374
2375         BUG_ON(fs_info->balance_ctl);
2376
2377         spin_lock(&fs_info->balance_lock);
2378         fs_info->balance_ctl = bctl;
2379         spin_unlock(&fs_info->balance_lock);
2380 }
2381
2382 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2383 {
2384         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2385
2386         BUG_ON(!fs_info->balance_ctl);
2387
2388         spin_lock(&fs_info->balance_lock);
2389         fs_info->balance_ctl = NULL;
2390         spin_unlock(&fs_info->balance_lock);
2391
2392         kfree(bctl);
2393 }
2394
2395 /*
2396  * Balance filters.  Return 1 if chunk should be filtered out
2397  * (should not be balanced).
2398  */
2399 static int chunk_profiles_filter(u64 chunk_type,
2400                                  struct btrfs_balance_args *bargs)
2401 {
2402         chunk_type = chunk_to_extended(chunk_type) &
2403                                 BTRFS_EXTENDED_PROFILE_MASK;
2404
2405         if (bargs->profiles & chunk_type)
2406                 return 0;
2407
2408         return 1;
2409 }
2410
2411 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2412                               struct btrfs_balance_args *bargs)
2413 {
2414         struct btrfs_block_group_cache *cache;
2415         u64 chunk_used, user_thresh;
2416         int ret = 1;
2417
2418         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2419         chunk_used = btrfs_block_group_used(&cache->item);
2420
2421         user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
2422         if (chunk_used < user_thresh)
2423                 ret = 0;
2424
2425         btrfs_put_block_group(cache);
2426         return ret;
2427 }
2428
2429 static int chunk_devid_filter(struct extent_buffer *leaf,
2430                               struct btrfs_chunk *chunk,
2431                               struct btrfs_balance_args *bargs)
2432 {
2433         struct btrfs_stripe *stripe;
2434         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2435         int i;
2436
2437         for (i = 0; i < num_stripes; i++) {
2438                 stripe = btrfs_stripe_nr(chunk, i);
2439                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2440                         return 0;
2441         }
2442
2443         return 1;
2444 }
2445
2446 /* [pstart, pend) */
2447 static int chunk_drange_filter(struct extent_buffer *leaf,
2448                                struct btrfs_chunk *chunk,
2449                                u64 chunk_offset,
2450                                struct btrfs_balance_args *bargs)
2451 {
2452         struct btrfs_stripe *stripe;
2453         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2454         u64 stripe_offset;
2455         u64 stripe_length;
2456         int factor;
2457         int i;
2458
2459         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2460                 return 0;
2461
2462         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2463              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
2464                 factor = 2;
2465         else
2466                 factor = 1;
2467         factor = num_stripes / factor;
2468
2469         for (i = 0; i < num_stripes; i++) {
2470                 stripe = btrfs_stripe_nr(chunk, i);
2471                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2472                         continue;
2473
2474                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2475                 stripe_length = btrfs_chunk_length(leaf, chunk);
2476                 do_div(stripe_length, factor);
2477
2478                 if (stripe_offset < bargs->pend &&
2479                     stripe_offset + stripe_length > bargs->pstart)
2480                         return 0;
2481         }
2482
2483         return 1;
2484 }
2485
2486 /* [vstart, vend) */
2487 static int chunk_vrange_filter(struct extent_buffer *leaf,
2488                                struct btrfs_chunk *chunk,
2489                                u64 chunk_offset,
2490                                struct btrfs_balance_args *bargs)
2491 {
2492         if (chunk_offset < bargs->vend &&
2493             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2494                 /* at least part of the chunk is inside this vrange */
2495                 return 0;
2496
2497         return 1;
2498 }
2499
2500 static int chunk_soft_convert_filter(u64 chunk_type,
2501                                      struct btrfs_balance_args *bargs)
2502 {
2503         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2504                 return 0;
2505
2506         chunk_type = chunk_to_extended(chunk_type) &
2507                                 BTRFS_EXTENDED_PROFILE_MASK;
2508
2509         if (bargs->target == chunk_type)
2510                 return 1;
2511
2512         return 0;
2513 }
2514
2515 static int should_balance_chunk(struct btrfs_root *root,
2516                                 struct extent_buffer *leaf,
2517                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2518 {
2519         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2520         struct btrfs_balance_args *bargs = NULL;
2521         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2522
2523         /* type filter */
2524         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2525               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2526                 return 0;
2527         }
2528
2529         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2530                 bargs = &bctl->data;
2531         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2532                 bargs = &bctl->sys;
2533         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2534                 bargs = &bctl->meta;
2535
2536         /* profiles filter */
2537         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2538             chunk_profiles_filter(chunk_type, bargs)) {
2539                 return 0;
2540         }
2541
2542         /* usage filter */
2543         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2544             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2545                 return 0;
2546         }
2547
2548         /* devid filter */
2549         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2550             chunk_devid_filter(leaf, chunk, bargs)) {
2551                 return 0;
2552         }
2553
2554         /* drange filter, makes sense only with devid filter */
2555         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2556             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2557                 return 0;
2558         }
2559
2560         /* vrange filter */
2561         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2562             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2563                 return 0;
2564         }
2565
2566         /* soft profile changing mode */
2567         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2568             chunk_soft_convert_filter(chunk_type, bargs)) {
2569                 return 0;
2570         }
2571
2572         return 1;
2573 }
2574
2575 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2576 {
2577         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2578         struct btrfs_root *chunk_root = fs_info->chunk_root;
2579         struct btrfs_root *dev_root = fs_info->dev_root;
2580         struct list_head *devices;
2581         struct btrfs_device *device;
2582         u64 old_size;
2583         u64 size_to_free;
2584         struct btrfs_chunk *chunk;
2585         struct btrfs_path *path;
2586         struct btrfs_key key;
2587         struct btrfs_key found_key;
2588         struct btrfs_trans_handle *trans;
2589         struct extent_buffer *leaf;
2590         int slot;
2591         int ret;
2592         int enospc_errors = 0;
2593         bool counting = true;
2594
2595         /* step one make some room on all the devices */
2596         devices = &fs_info->fs_devices->devices;
2597         list_for_each_entry(device, devices, dev_list) {
2598                 old_size = device->total_bytes;
2599                 size_to_free = div_factor(old_size, 1);
2600                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2601                 if (!device->writeable ||
2602                     device->total_bytes - device->bytes_used > size_to_free)
2603                         continue;
2604
2605                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2606                 if (ret == -ENOSPC)
2607                         break;
2608                 BUG_ON(ret);
2609
2610                 trans = btrfs_start_transaction(dev_root, 0);
2611                 BUG_ON(IS_ERR(trans));
2612
2613                 ret = btrfs_grow_device(trans, device, old_size);
2614                 BUG_ON(ret);
2615
2616                 btrfs_end_transaction(trans, dev_root);
2617         }
2618
2619         /* step two, relocate all the chunks */
2620         path = btrfs_alloc_path();
2621         if (!path) {
2622                 ret = -ENOMEM;
2623                 goto error;
2624         }
2625
2626         /* zero out stat counters */
2627         spin_lock(&fs_info->balance_lock);
2628         memset(&bctl->stat, 0, sizeof(bctl->stat));
2629         spin_unlock(&fs_info->balance_lock);
2630 again:
2631         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2632         key.offset = (u64)-1;
2633         key.type = BTRFS_CHUNK_ITEM_KEY;
2634
2635         while (1) {
2636                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2637                     atomic_read(&fs_info->balance_cancel_req)) {
2638                         ret = -ECANCELED;
2639                         goto error;
2640                 }
2641
2642                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2643                 if (ret < 0)
2644                         goto error;
2645
2646                 /*
2647                  * this shouldn't happen, it means the last relocate
2648                  * failed
2649                  */
2650                 if (ret == 0)
2651                         BUG(); /* FIXME break ? */
2652
2653                 ret = btrfs_previous_item(chunk_root, path, 0,
2654                                           BTRFS_CHUNK_ITEM_KEY);
2655                 if (ret) {
2656                         ret = 0;
2657                         break;
2658                 }
2659
2660                 leaf = path->nodes[0];
2661                 slot = path->slots[0];
2662                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2663
2664                 if (found_key.objectid != key.objectid)
2665                         break;
2666
2667                 /* chunk zero is special */
2668                 if (found_key.offset == 0)
2669                         break;
2670
2671                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2672
2673                 if (!counting) {
2674                         spin_lock(&fs_info->balance_lock);
2675                         bctl->stat.considered++;
2676                         spin_unlock(&fs_info->balance_lock);
2677                 }
2678
2679                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2680                                            found_key.offset);
2681                 btrfs_release_path(path);
2682                 if (!ret)
2683                         goto loop;
2684
2685                 if (counting) {
2686                         spin_lock(&fs_info->balance_lock);
2687                         bctl->stat.expected++;
2688                         spin_unlock(&fs_info->balance_lock);
2689                         goto loop;
2690                 }
2691
2692                 ret = btrfs_relocate_chunk(chunk_root,
2693                                            chunk_root->root_key.objectid,
2694                                            found_key.objectid,
2695                                            found_key.offset);
2696                 if (ret && ret != -ENOSPC)
2697                         goto error;
2698                 if (ret == -ENOSPC) {
2699                         enospc_errors++;
2700                 } else {
2701                         spin_lock(&fs_info->balance_lock);
2702                         bctl->stat.completed++;
2703                         spin_unlock(&fs_info->balance_lock);
2704                 }
2705 loop:
2706                 key.offset = found_key.offset - 1;
2707         }
2708
2709         if (counting) {
2710                 btrfs_release_path(path);
2711                 counting = false;
2712                 goto again;
2713         }
2714 error:
2715         btrfs_free_path(path);
2716         if (enospc_errors) {
2717                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2718                        enospc_errors);
2719                 if (!ret)
2720                         ret = -ENOSPC;
2721         }
2722
2723         return ret;
2724 }
2725
2726 /**
2727  * alloc_profile_is_valid - see if a given profile is valid and reduced
2728  * @flags: profile to validate
2729  * @extended: if true @flags is treated as an extended profile
2730  */
2731 static int alloc_profile_is_valid(u64 flags, int extended)
2732 {
2733         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
2734                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
2735
2736         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
2737
2738         /* 1) check that all other bits are zeroed */
2739         if (flags & ~mask)
2740                 return 0;
2741
2742         /* 2) see if profile is reduced */
2743         if (flags == 0)
2744                 return !extended; /* "0" is valid for usual profiles */
2745
2746         /* true if exactly one bit set */
2747         return (flags & (flags - 1)) == 0;
2748 }
2749
2750 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
2751 {
2752         /* cancel requested || normal exit path */
2753         return atomic_read(&fs_info->balance_cancel_req) ||
2754                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
2755                  atomic_read(&fs_info->balance_cancel_req) == 0);
2756 }
2757
2758 static void __cancel_balance(struct btrfs_fs_info *fs_info)
2759 {
2760         int ret;
2761
2762         unset_balance_control(fs_info);
2763         ret = del_balance_item(fs_info->tree_root);
2764         BUG_ON(ret);
2765 }
2766
2767 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
2768                                struct btrfs_ioctl_balance_args *bargs);
2769
2770 /*
2771  * Should be called with both balance and volume mutexes held
2772  */
2773 int btrfs_balance(struct btrfs_balance_control *bctl,
2774                   struct btrfs_ioctl_balance_args *bargs)
2775 {
2776         struct btrfs_fs_info *fs_info = bctl->fs_info;
2777         u64 allowed;
2778         int mixed = 0;
2779         int ret;
2780
2781         if (btrfs_fs_closing(fs_info) ||
2782             atomic_read(&fs_info->balance_pause_req) ||
2783             atomic_read(&fs_info->balance_cancel_req)) {
2784                 ret = -EINVAL;
2785                 goto out;
2786         }
2787
2788         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2789         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
2790                 mixed = 1;
2791
2792         /*
2793          * In case of mixed groups both data and meta should be picked,
2794          * and identical options should be given for both of them.
2795          */
2796         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
2797         if (mixed && (bctl->flags & allowed)) {
2798                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
2799                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
2800                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
2801                         printk(KERN_ERR "btrfs: with mixed groups data and "
2802                                "metadata balance options must be the same\n");
2803                         ret = -EINVAL;
2804                         goto out;
2805                 }
2806         }
2807
2808         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
2809         if (fs_info->fs_devices->num_devices == 1)
2810                 allowed |= BTRFS_BLOCK_GROUP_DUP;
2811         else if (fs_info->fs_devices->num_devices < 4)
2812                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
2813         else
2814                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2815                                 BTRFS_BLOCK_GROUP_RAID10);
2816
2817         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2818             (!alloc_profile_is_valid(bctl->data.target, 1) ||
2819              (bctl->data.target & ~allowed))) {
2820                 printk(KERN_ERR "btrfs: unable to start balance with target "
2821                        "data profile %llu\n",
2822                        (unsigned long long)bctl->data.target);
2823                 ret = -EINVAL;
2824                 goto out;
2825         }
2826         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2827             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
2828              (bctl->meta.target & ~allowed))) {
2829                 printk(KERN_ERR "btrfs: unable to start balance with target "
2830                        "metadata profile %llu\n",
2831                        (unsigned long long)bctl->meta.target);
2832                 ret = -EINVAL;
2833                 goto out;
2834         }
2835         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2836             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
2837              (bctl->sys.target & ~allowed))) {
2838                 printk(KERN_ERR "btrfs: unable to start balance with target "
2839                        "system profile %llu\n",
2840                        (unsigned long long)bctl->sys.target);
2841                 ret = -EINVAL;
2842                 goto out;
2843         }
2844
2845         /* allow dup'ed data chunks only in mixed mode */
2846         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2847             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
2848                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
2849                 ret = -EINVAL;
2850                 goto out;
2851         }
2852
2853         /* allow to reduce meta or sys integrity only if force set */
2854         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2855                         BTRFS_BLOCK_GROUP_RAID10;
2856         if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2857              (fs_info->avail_system_alloc_bits & allowed) &&
2858              !(bctl->sys.target & allowed)) ||
2859             ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2860              (fs_info->avail_metadata_alloc_bits & allowed) &&
2861              !(bctl->meta.target & allowed))) {
2862                 if (bctl->flags & BTRFS_BALANCE_FORCE) {
2863                         printk(KERN_INFO "btrfs: force reducing metadata "
2864                                "integrity\n");
2865                 } else {
2866                         printk(KERN_ERR "btrfs: balance will reduce metadata "
2867                                "integrity, use force if you want this\n");
2868                         ret = -EINVAL;
2869                         goto out;
2870                 }
2871         }
2872
2873         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
2874                 int num_tolerated_disk_barrier_failures;
2875                 u64 target = bctl->sys.target;
2876
2877                 num_tolerated_disk_barrier_failures =
2878                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2879                 if (num_tolerated_disk_barrier_failures > 0 &&
2880                     (target &
2881                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
2882                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
2883                         num_tolerated_disk_barrier_failures = 0;
2884                 else if (num_tolerated_disk_barrier_failures > 1 &&
2885                          (target &
2886                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
2887                         num_tolerated_disk_barrier_failures = 1;
2888
2889                 fs_info->num_tolerated_disk_barrier_failures =
2890                         num_tolerated_disk_barrier_failures;
2891         }
2892
2893         ret = insert_balance_item(fs_info->tree_root, bctl);
2894         if (ret && ret != -EEXIST)
2895                 goto out;
2896
2897         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
2898                 BUG_ON(ret == -EEXIST);
2899                 set_balance_control(bctl);
2900         } else {
2901                 BUG_ON(ret != -EEXIST);
2902                 spin_lock(&fs_info->balance_lock);
2903                 update_balance_args(bctl);
2904                 spin_unlock(&fs_info->balance_lock);
2905         }
2906
2907         atomic_inc(&fs_info->balance_running);
2908         mutex_unlock(&fs_info->balance_mutex);
2909
2910         ret = __btrfs_balance(fs_info);
2911
2912         mutex_lock(&fs_info->balance_mutex);
2913         atomic_dec(&fs_info->balance_running);
2914
2915         if (bargs) {
2916                 memset(bargs, 0, sizeof(*bargs));
2917                 update_ioctl_balance_args(fs_info, 0, bargs);
2918         }
2919
2920         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
2921             balance_need_close(fs_info)) {
2922                 __cancel_balance(fs_info);
2923         }
2924
2925         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
2926                 fs_info->num_tolerated_disk_barrier_failures =
2927                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2928         }
2929
2930         wake_up(&fs_info->balance_wait_q);
2931
2932         return ret;
2933 out:
2934         if (bctl->flags & BTRFS_BALANCE_RESUME)
2935                 __cancel_balance(fs_info);
2936         else
2937                 kfree(bctl);
2938         return ret;
2939 }
2940
2941 static int balance_kthread(void *data)
2942 {
2943         struct btrfs_fs_info *fs_info = data;
2944         int ret = 0;
2945
2946         mutex_lock(&fs_info->volume_mutex);
2947         mutex_lock(&fs_info->balance_mutex);
2948
2949         if (fs_info->balance_ctl) {
2950                 printk(KERN_INFO "btrfs: continuing balance\n");
2951                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
2952         }
2953
2954         mutex_unlock(&fs_info->balance_mutex);
2955         mutex_unlock(&fs_info->volume_mutex);
2956
2957         return ret;
2958 }
2959
2960 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
2961 {
2962         struct task_struct *tsk;
2963
2964         spin_lock(&fs_info->balance_lock);
2965         if (!fs_info->balance_ctl) {
2966                 spin_unlock(&fs_info->balance_lock);
2967                 return 0;
2968         }
2969         spin_unlock(&fs_info->balance_lock);
2970
2971         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
2972                 printk(KERN_INFO "btrfs: force skipping balance\n");
2973                 return 0;
2974         }
2975
2976         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
2977         if (IS_ERR(tsk))
2978                 return PTR_ERR(tsk);
2979
2980         return 0;
2981 }
2982
2983 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
2984 {
2985         struct btrfs_balance_control *bctl;
2986         struct btrfs_balance_item *item;
2987         struct btrfs_disk_balance_args disk_bargs;
2988         struct btrfs_path *path;
2989         struct extent_buffer *leaf;
2990         struct btrfs_key key;
2991         int ret;
2992
2993         path = btrfs_alloc_path();
2994         if (!path)
2995                 return -ENOMEM;
2996
2997         key.objectid = BTRFS_BALANCE_OBJECTID;
2998         key.type = BTRFS_BALANCE_ITEM_KEY;
2999         key.offset = 0;
3000
3001         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3002         if (ret < 0)
3003                 goto out;
3004         if (ret > 0) { /* ret = -ENOENT; */
3005                 ret = 0;
3006                 goto out;
3007         }
3008
3009         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3010         if (!bctl) {
3011                 ret = -ENOMEM;
3012                 goto out;
3013         }
3014
3015         leaf = path->nodes[0];
3016         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3017
3018         bctl->fs_info = fs_info;
3019         bctl->flags = btrfs_balance_flags(leaf, item);
3020         bctl->flags |= BTRFS_BALANCE_RESUME;
3021
3022         btrfs_balance_data(leaf, item, &disk_bargs);
3023         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3024         btrfs_balance_meta(leaf, item, &disk_bargs);
3025         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3026         btrfs_balance_sys(leaf, item, &disk_bargs);
3027         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3028
3029         mutex_lock(&fs_info->volume_mutex);
3030         mutex_lock(&fs_info->balance_mutex);
3031
3032         set_balance_control(bctl);
3033
3034         mutex_unlock(&fs_info->balance_mutex);
3035         mutex_unlock(&fs_info->volume_mutex);
3036 out:
3037         btrfs_free_path(path);
3038         return ret;
3039 }
3040
3041 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3042 {
3043         int ret = 0;
3044
3045         mutex_lock(&fs_info->balance_mutex);
3046         if (!fs_info->balance_ctl) {
3047                 mutex_unlock(&fs_info->balance_mutex);
3048                 return -ENOTCONN;
3049         }
3050
3051         if (atomic_read(&fs_info->balance_running)) {
3052                 atomic_inc(&fs_info->balance_pause_req);
3053                 mutex_unlock(&fs_info->balance_mutex);
3054
3055                 wait_event(fs_info->balance_wait_q,
3056                            atomic_read(&fs_info->balance_running) == 0);
3057
3058                 mutex_lock(&fs_info->balance_mutex);
3059                 /* we are good with balance_ctl ripped off from under us */
3060                 BUG_ON(atomic_read(&fs_info->balance_running));
3061                 atomic_dec(&fs_info->balance_pause_req);
3062         } else {
3063                 ret = -ENOTCONN;
3064         }
3065
3066         mutex_unlock(&fs_info->balance_mutex);
3067         return ret;
3068 }
3069
3070 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3071 {
3072         mutex_lock(&fs_info->balance_mutex);
3073         if (!fs_info->balance_ctl) {
3074                 mutex_unlock(&fs_info->balance_mutex);
3075                 return -ENOTCONN;
3076         }
3077
3078         atomic_inc(&fs_info->balance_cancel_req);
3079         /*
3080          * if we are running just wait and return, balance item is
3081          * deleted in btrfs_balance in this case
3082          */
3083         if (atomic_read(&fs_info->balance_running)) {
3084                 mutex_unlock(&fs_info->balance_mutex);
3085                 wait_event(fs_info->balance_wait_q,
3086                            atomic_read(&fs_info->balance_running) == 0);
3087                 mutex_lock(&fs_info->balance_mutex);
3088         } else {
3089                 /* __cancel_balance needs volume_mutex */
3090                 mutex_unlock(&fs_info->balance_mutex);
3091                 mutex_lock(&fs_info->volume_mutex);
3092                 mutex_lock(&fs_info->balance_mutex);
3093
3094                 if (fs_info->balance_ctl)
3095                         __cancel_balance(fs_info);
3096
3097                 mutex_unlock(&fs_info->volume_mutex);
3098         }
3099
3100         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3101         atomic_dec(&fs_info->balance_cancel_req);
3102         mutex_unlock(&fs_info->balance_mutex);
3103         return 0;
3104 }
3105
3106 /*
3107  * shrinking a device means finding all of the device extents past
3108  * the new size, and then following the back refs to the chunks.
3109  * The chunk relocation code actually frees the device extent
3110  */
3111 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3112 {
3113         struct btrfs_trans_handle *trans;
3114         struct btrfs_root *root = device->dev_root;
3115         struct btrfs_dev_extent *dev_extent = NULL;
3116         struct btrfs_path *path;
3117         u64 length;
3118         u64 chunk_tree;
3119         u64 chunk_objectid;
3120         u64 chunk_offset;
3121         int ret;
3122         int slot;
3123         int failed = 0;
3124         bool retried = false;
3125         struct extent_buffer *l;
3126         struct btrfs_key key;
3127         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3128         u64 old_total = btrfs_super_total_bytes(super_copy);
3129         u64 old_size = device->total_bytes;
3130         u64 diff = device->total_bytes - new_size;
3131
3132         path = btrfs_alloc_path();
3133         if (!path)
3134                 return -ENOMEM;
3135
3136         path->reada = 2;
3137
3138         lock_chunks(root);
3139
3140         device->total_bytes = new_size;
3141         if (device->writeable) {
3142                 device->fs_devices->total_rw_bytes -= diff;
3143                 spin_lock(&root->fs_info->free_chunk_lock);
3144                 root->fs_info->free_chunk_space -= diff;
3145                 spin_unlock(&root->fs_info->free_chunk_lock);
3146         }
3147         unlock_chunks(root);
3148
3149 again:
3150         key.objectid = device->devid;
3151         key.offset = (u64)-1;
3152         key.type = BTRFS_DEV_EXTENT_KEY;
3153
3154         do {
3155                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3156                 if (ret < 0)
3157                         goto done;
3158
3159                 ret = btrfs_previous_item(root, path, 0, key.type);
3160                 if (ret < 0)
3161                         goto done;
3162                 if (ret) {
3163                         ret = 0;
3164                         btrfs_release_path(path);
3165                         break;
3166                 }
3167
3168                 l = path->nodes[0];
3169                 slot = path->slots[0];
3170                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3171
3172                 if (key.objectid != device->devid) {
3173                         btrfs_release_path(path);
3174                         break;
3175                 }
3176
3177                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3178                 length = btrfs_dev_extent_length(l, dev_extent);
3179
3180                 if (key.offset + length <= new_size) {
3181                         btrfs_release_path(path);
3182                         break;
3183                 }
3184
3185                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3186                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3187                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3188                 btrfs_release_path(path);
3189
3190                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3191                                            chunk_offset);
3192                 if (ret && ret != -ENOSPC)
3193                         goto done;
3194                 if (ret == -ENOSPC)
3195                         failed++;
3196         } while (key.offset-- > 0);
3197
3198         if (failed && !retried) {
3199                 failed = 0;
3200                 retried = true;
3201                 goto again;
3202         } else if (failed && retried) {
3203                 ret = -ENOSPC;
3204                 lock_chunks(root);
3205
3206                 device->total_bytes = old_size;
3207                 if (device->writeable)
3208                         device->fs_devices->total_rw_bytes += diff;
3209                 spin_lock(&root->fs_info->free_chunk_lock);
3210                 root->fs_info->free_chunk_space += diff;
3211                 spin_unlock(&root->fs_info->free_chunk_lock);
3212                 unlock_chunks(root);
3213                 goto done;
3214         }
3215
3216         /* Shrinking succeeded, else we would be at "done". */
3217         trans = btrfs_start_transaction(root, 0);
3218         if (IS_ERR(trans)) {
3219                 ret = PTR_ERR(trans);
3220                 goto done;
3221         }
3222
3223         lock_chunks(root);
3224
3225         device->disk_total_bytes = new_size;
3226         /* Now btrfs_update_device() will change the on-disk size. */
3227         ret = btrfs_update_device(trans, device);
3228         if (ret) {
3229                 unlock_chunks(root);
3230                 btrfs_end_transaction(trans, root);
3231                 goto done;
3232         }
3233         WARN_ON(diff > old_total);
3234         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3235         unlock_chunks(root);
3236         btrfs_end_transaction(trans, root);
3237 done:
3238         btrfs_free_path(path);
3239         return ret;
3240 }
3241
3242 static int btrfs_add_system_chunk(struct btrfs_root *root,
3243                            struct btrfs_key *key,
3244                            struct btrfs_chunk *chunk, int item_size)
3245 {
3246         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3247         struct btrfs_disk_key disk_key;
3248         u32 array_size;
3249         u8 *ptr;
3250
3251         array_size = btrfs_super_sys_array_size(super_copy);
3252         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3253                 return -EFBIG;
3254
3255         ptr = super_copy->sys_chunk_array + array_size;
3256         btrfs_cpu_key_to_disk(&disk_key, key);
3257         memcpy(ptr, &disk_key, sizeof(disk_key));
3258         ptr += sizeof(disk_key);
3259         memcpy(ptr, chunk, item_size);
3260         item_size += sizeof(disk_key);
3261         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3262         return 0;
3263 }
3264
3265 /*
3266  * sort the devices in descending order by max_avail, total_avail
3267  */
3268 static int btrfs_cmp_device_info(const void *a, const void *b)
3269 {
3270         const struct btrfs_device_info *di_a = a;
3271         const struct btrfs_device_info *di_b = b;
3272
3273         if (di_a->max_avail > di_b->max_avail)
3274                 return -1;
3275         if (di_a->max_avail < di_b->max_avail)
3276                 return 1;
3277         if (di_a->total_avail > di_b->total_avail)
3278                 return -1;
3279         if (di_a->total_avail < di_b->total_avail)
3280                 return 1;
3281         return 0;
3282 }
3283
3284 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3285                                struct btrfs_root *extent_root,
3286                                struct map_lookup **map_ret,
3287                                u64 *num_bytes_out, u64 *stripe_size_out,
3288                                u64 start, u64 type)
3289 {
3290         struct btrfs_fs_info *info = extent_root->fs_info;
3291         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3292         struct list_head *cur;
3293         struct map_lookup *map = NULL;
3294         struct extent_map_tree *em_tree;
3295         struct extent_map *em;
3296         struct btrfs_device_info *devices_info = NULL;
3297         u64 total_avail;
3298         int num_stripes;        /* total number of stripes to allocate */
3299         int sub_stripes;        /* sub_stripes info for map */
3300         int dev_stripes;        /* stripes per dev */
3301         int devs_max;           /* max devs to use */
3302         int devs_min;           /* min devs needed */
3303         int devs_increment;     /* ndevs has to be a multiple of this */
3304         int ncopies;            /* how many copies to data has */
3305         int ret;
3306         u64 max_stripe_size;
3307         u64 max_chunk_size;
3308         u64 stripe_size;
3309         u64 num_bytes;
3310         int ndevs;
3311         int i;
3312         int j;
3313
3314         BUG_ON(!alloc_profile_is_valid(type, 0));
3315
3316         if (list_empty(&fs_devices->alloc_list))
3317                 return -ENOSPC;
3318
3319         sub_stripes = 1;
3320         dev_stripes = 1;
3321         devs_increment = 1;
3322         ncopies = 1;
3323         devs_max = 0;   /* 0 == as many as possible */
3324         devs_min = 1;
3325
3326         /*
3327          * define the properties of each RAID type.
3328          * FIXME: move this to a global table and use it in all RAID
3329          * calculation code
3330          */
3331         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
3332                 dev_stripes = 2;
3333                 ncopies = 2;
3334                 devs_max = 1;
3335         } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
3336                 devs_min = 2;
3337         } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
3338                 devs_increment = 2;
3339                 ncopies = 2;
3340                 devs_max = 2;
3341                 devs_min = 2;
3342         } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
3343                 sub_stripes = 2;
3344                 devs_increment = 2;
3345                 ncopies = 2;
3346                 devs_min = 4;
3347         } else {
3348                 devs_max = 1;
3349         }
3350
3351         if (type & BTRFS_BLOCK_GROUP_DATA) {
3352                 max_stripe_size = 1024 * 1024 * 1024;
3353                 max_chunk_size = 10 * max_stripe_size;
3354         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3355                 /* for larger filesystems, use larger metadata chunks */
3356                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3357                         max_stripe_size = 1024 * 1024 * 1024;
3358                 else
3359                         max_stripe_size = 256 * 1024 * 1024;
3360                 max_chunk_size = max_stripe_size;
3361         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3362                 max_stripe_size = 32 * 1024 * 1024;
3363                 max_chunk_size = 2 * max_stripe_size;
3364         } else {
3365                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3366                        type);
3367                 BUG_ON(1);
3368         }
3369
3370         /* we don't want a chunk larger than 10% of writeable space */
3371         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3372                              max_chunk_size);
3373
3374         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3375                                GFP_NOFS);
3376         if (!devices_info)
3377                 return -ENOMEM;
3378
3379         cur = fs_devices->alloc_list.next;
3380
3381         /*
3382          * in the first pass through the devices list, we gather information
3383          * about the available holes on each device.
3384          */
3385         ndevs = 0;
3386         while (cur != &fs_devices->alloc_list) {
3387                 struct btrfs_device *device;
3388                 u64 max_avail;
3389                 u64 dev_offset;
3390
3391                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3392
3393                 cur = cur->next;
3394
3395                 if (!device->writeable) {
3396                         WARN(1, KERN_ERR
3397                                "btrfs: read-only device in alloc_list\n");
3398                         continue;
3399                 }
3400
3401                 if (!device->in_fs_metadata)
3402                         continue;
3403
3404                 if (device->total_bytes > device->bytes_used)
3405                         total_avail = device->total_bytes - device->bytes_used;
3406                 else
3407                         total_avail = 0;
3408
3409                 /* If there is no space on this device, skip it. */
3410                 if (total_avail == 0)
3411                         continue;
3412
3413                 ret = find_free_dev_extent(device,
3414                                            max_stripe_size * dev_stripes,
3415                                            &dev_offset, &max_avail);
3416                 if (ret && ret != -ENOSPC)
3417                         goto error;
3418
3419                 if (ret == 0)
3420                         max_avail = max_stripe_size * dev_stripes;
3421
3422                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3423                         continue;
3424
3425                 devices_info[ndevs].dev_offset = dev_offset;
3426                 devices_info[ndevs].max_avail = max_avail;
3427                 devices_info[ndevs].total_avail = total_avail;
3428                 devices_info[ndevs].dev = device;
3429                 ++ndevs;
3430         }
3431
3432         /*
3433          * now sort the devices by hole size / available space
3434          */
3435         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3436              btrfs_cmp_device_info, NULL);
3437
3438         /* round down to number of usable stripes */
3439         ndevs -= ndevs % devs_increment;
3440
3441         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3442                 ret = -ENOSPC;
3443                 goto error;
3444         }
3445
3446         if (devs_max && ndevs > devs_max)
3447                 ndevs = devs_max;
3448         /*
3449          * the primary goal is to maximize the number of stripes, so use as many
3450          * devices as possible, even if the stripes are not maximum sized.
3451          */
3452         stripe_size = devices_info[ndevs-1].max_avail;
3453         num_stripes = ndevs * dev_stripes;
3454
3455         if (stripe_size * ndevs > max_chunk_size * ncopies) {
3456                 stripe_size = max_chunk_size * ncopies;
3457                 do_div(stripe_size, ndevs);
3458         }
3459
3460         do_div(stripe_size, dev_stripes);
3461
3462         /* align to BTRFS_STRIPE_LEN */
3463         do_div(stripe_size, BTRFS_STRIPE_LEN);
3464         stripe_size *= BTRFS_STRIPE_LEN;
3465
3466         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3467         if (!map) {
3468                 ret = -ENOMEM;
3469                 goto error;
3470         }
3471         map->num_stripes = num_stripes;
3472
3473         for (i = 0; i < ndevs; ++i) {
3474                 for (j = 0; j < dev_stripes; ++j) {
3475                         int s = i * dev_stripes + j;
3476                         map->stripes[s].dev = devices_info[i].dev;
3477                         map->stripes[s].physical = devices_info[i].dev_offset +
3478                                                    j * stripe_size;
3479                 }
3480         }
3481         map->sector_size = extent_root->sectorsize;
3482         map->stripe_len = BTRFS_STRIPE_LEN;
3483         map->io_align = BTRFS_STRIPE_LEN;
3484         map->io_width = BTRFS_STRIPE_LEN;
3485         map->type = type;
3486         map->sub_stripes = sub_stripes;
3487
3488         *map_ret = map;
3489         num_bytes = stripe_size * (num_stripes / ncopies);
3490
3491         *stripe_size_out = stripe_size;
3492         *num_bytes_out = num_bytes;
3493
3494         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3495
3496         em = alloc_extent_map();
3497         if (!em) {
3498                 ret = -ENOMEM;
3499                 goto error;
3500         }
3501         em->bdev = (struct block_device *)map;
3502         em->start = start;
3503         em->len = num_bytes;
3504         em->block_start = 0;
3505         em->block_len = em->len;
3506
3507         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3508         write_lock(&em_tree->lock);
3509         ret = add_extent_mapping(em_tree, em);
3510         write_unlock(&em_tree->lock);
3511         free_extent_map(em);
3512         if (ret)
3513                 goto error;
3514
3515         ret = btrfs_make_block_group(trans, extent_root, 0, type,
3516                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3517                                      start, num_bytes);
3518         if (ret)
3519                 goto error;
3520
3521         for (i = 0; i < map->num_stripes; ++i) {
3522                 struct btrfs_device *device;
3523                 u64 dev_offset;
3524
3525                 device = map->stripes[i].dev;
3526                 dev_offset = map->stripes[i].physical;
3527
3528                 ret = btrfs_alloc_dev_extent(trans, device,
3529                                 info->chunk_root->root_key.objectid,
3530                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3531                                 start, dev_offset, stripe_size);
3532                 if (ret) {
3533                         btrfs_abort_transaction(trans, extent_root, ret);
3534                         goto error;
3535                 }
3536         }
3537
3538         kfree(devices_info);
3539         return 0;
3540
3541 error:
3542         kfree(map);
3543         kfree(devices_info);
3544         return ret;
3545 }
3546
3547 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3548                                 struct btrfs_root *extent_root,
3549                                 struct map_lookup *map, u64 chunk_offset,
3550                                 u64 chunk_size, u64 stripe_size)
3551 {
3552         u64 dev_offset;
3553         struct btrfs_key key;
3554         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3555         struct btrfs_device *device;
3556         struct btrfs_chunk *chunk;
3557         struct btrfs_stripe *stripe;
3558         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
3559         int index = 0;
3560         int ret;
3561
3562         chunk = kzalloc(item_size, GFP_NOFS);
3563         if (!chunk)
3564                 return -ENOMEM;
3565
3566         index = 0;
3567         while (index < map->num_stripes) {
3568                 device = map->stripes[index].dev;
3569                 device->bytes_used += stripe_size;
3570                 ret = btrfs_update_device(trans, device);
3571                 if (ret)
3572                         goto out_free;
3573                 index++;
3574         }
3575
3576         spin_lock(&extent_root->fs_info->free_chunk_lock);
3577         extent_root->fs_info->free_chunk_space -= (stripe_size *
3578                                                    map->num_stripes);
3579         spin_unlock(&extent_root->fs_info->free_chunk_lock);
3580
3581         index = 0;
3582         stripe = &chunk->stripe;
3583         while (index < map->num_stripes) {
3584                 device = map->stripes[index].dev;
3585                 dev_offset = map->stripes[index].physical;
3586
3587                 btrfs_set_stack_stripe_devid(stripe, device->devid);
3588                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
3589                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
3590                 stripe++;
3591                 index++;
3592         }
3593
3594         btrfs_set_stack_chunk_length(chunk, chunk_size);
3595         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
3596         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
3597         btrfs_set_stack_chunk_type(chunk, map->type);
3598         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
3599         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
3600         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
3601         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
3602         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
3603
3604         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3605         key.type = BTRFS_CHUNK_ITEM_KEY;
3606         key.offset = chunk_offset;
3607
3608         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
3609
3610         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
3611                 /*
3612                  * TODO: Cleanup of inserted chunk root in case of
3613                  * failure.
3614                  */
3615                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
3616                                              item_size);
3617         }
3618
3619 out_free:
3620         kfree(chunk);
3621         return ret;
3622 }
3623
3624 /*
3625  * Chunk allocation falls into two parts. The first part does works
3626  * that make the new allocated chunk useable, but not do any operation
3627  * that modifies the chunk tree. The second part does the works that
3628  * require modifying the chunk tree. This division is important for the
3629  * bootstrap process of adding storage to a seed btrfs.
3630  */
3631 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3632                       struct btrfs_root *extent_root, u64 type)
3633 {
3634         u64 chunk_offset;
3635         u64 chunk_size;
3636         u64 stripe_size;
3637         struct map_lookup *map;
3638         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3639         int ret;
3640
3641         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3642                               &chunk_offset);
3643         if (ret)
3644                 return ret;
3645
3646         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3647                                   &stripe_size, chunk_offset, type);
3648         if (ret)
3649                 return ret;
3650
3651         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3652                                    chunk_size, stripe_size);
3653         if (ret)
3654                 return ret;
3655         return 0;
3656 }
3657
3658 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
3659                                          struct btrfs_root *root,
3660                                          struct btrfs_device *device)
3661 {
3662         u64 chunk_offset;
3663         u64 sys_chunk_offset;
3664         u64 chunk_size;
3665         u64 sys_chunk_size;
3666         u64 stripe_size;
3667         u64 sys_stripe_size;
3668         u64 alloc_profile;
3669         struct map_lookup *map;
3670         struct map_lookup *sys_map;
3671         struct btrfs_fs_info *fs_info = root->fs_info;
3672         struct btrfs_root *extent_root = fs_info->extent_root;
3673         int ret;
3674
3675         ret = find_next_chunk(fs_info->chunk_root,
3676                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
3677         if (ret)
3678                 return ret;
3679
3680         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
3681                                 fs_info->avail_metadata_alloc_bits;
3682         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3683
3684         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3685                                   &stripe_size, chunk_offset, alloc_profile);
3686         if (ret)
3687                 return ret;
3688
3689         sys_chunk_offset = chunk_offset + chunk_size;
3690
3691         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
3692                                 fs_info->avail_system_alloc_bits;
3693         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3694
3695         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
3696                                   &sys_chunk_size, &sys_stripe_size,
3697                                   sys_chunk_offset, alloc_profile);
3698         if (ret) {
3699                 btrfs_abort_transaction(trans, root, ret);
3700                 goto out;
3701         }
3702
3703         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
3704         if (ret) {
3705                 btrfs_abort_transaction(trans, root, ret);
3706                 goto out;
3707         }
3708
3709         /*
3710          * Modifying chunk tree needs allocating new blocks from both
3711          * system block group and metadata block group. So we only can
3712          * do operations require modifying the chunk tree after both
3713          * block groups were created.
3714          */
3715         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3716                                    chunk_size, stripe_size);
3717         if (ret) {
3718                 btrfs_abort_transaction(trans, root, ret);
3719                 goto out;
3720         }
3721
3722         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
3723                                    sys_chunk_offset, sys_chunk_size,
3724                                    sys_stripe_size);
3725         if (ret)
3726                 btrfs_abort_transaction(trans, root, ret);
3727
3728 out:
3729
3730         return ret;
3731 }
3732
3733 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
3734 {
3735         struct extent_map *em;
3736         struct map_lookup *map;
3737         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3738         int readonly = 0;
3739         int i;
3740
3741         read_lock(&map_tree->map_tree.lock);
3742         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3743         read_unlock(&map_tree->map_tree.lock);
3744         if (!em)
3745                 return 1;
3746
3747         if (btrfs_test_opt(root, DEGRADED)) {
3748                 free_extent_map(em);
3749                 return 0;
3750         }
3751
3752         map = (struct map_lookup *)em->bdev;
3753         for (i = 0; i < map->num_stripes; i++) {
3754                 if (!map->stripes[i].dev->writeable) {
3755                         readonly = 1;
3756                         break;
3757                 }
3758         }
3759         free_extent_map(em);
3760         return readonly;
3761 }
3762
3763 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
3764 {
3765         extent_map_tree_init(&tree->map_tree);
3766 }
3767
3768 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
3769 {
3770         struct extent_map *em;
3771
3772         while (1) {
3773                 write_lock(&tree->map_tree.lock);
3774                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
3775                 if (em)
3776                         remove_extent_mapping(&tree->map_tree, em);
3777                 write_unlock(&tree->map_tree.lock);
3778                 if (!em)
3779                         break;
3780                 kfree(em->bdev);
3781                 /* once for us */
3782                 free_extent_map(em);
3783                 /* once for the tree */
3784                 free_extent_map(em);
3785         }
3786 }
3787
3788 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
3789 {
3790         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
3791         struct extent_map *em;
3792         struct map_lookup *map;
3793         struct extent_map_tree *em_tree = &map_tree->map_tree;
3794         int ret;
3795
3796         read_lock(&em_tree->lock);
3797         em = lookup_extent_mapping(em_tree, logical, len);
3798         read_unlock(&em_tree->lock);
3799         BUG_ON(!em);
3800
3801         BUG_ON(em->start > logical || em->start + em->len < logical);
3802         map = (struct map_lookup *)em->bdev;
3803         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
3804                 ret = map->num_stripes;
3805         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
3806                 ret = map->sub_stripes;
3807         else
3808                 ret = 1;
3809         free_extent_map(em);
3810         return ret;
3811 }
3812
3813 static int find_live_mirror(struct map_lookup *map, int first, int num,
3814                             int optimal)
3815 {
3816         int i;
3817         if (map->stripes[optimal].dev->bdev)
3818                 return optimal;
3819         for (i = first; i < first + num; i++) {
3820                 if (map->stripes[i].dev->bdev)
3821                         return i;
3822         }
3823         /* we couldn't find one that doesn't fail.  Just return something
3824          * and the io error handling code will clean up eventually
3825          */
3826         return optimal;
3827 }
3828
3829 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3830                              u64 logical, u64 *length,
3831                              struct btrfs_bio **bbio_ret,
3832                              int mirror_num)
3833 {
3834         struct extent_map *em;
3835         struct map_lookup *map;
3836         struct extent_map_tree *em_tree = &map_tree->map_tree;
3837         u64 offset;
3838         u64 stripe_offset;
3839         u64 stripe_end_offset;
3840         u64 stripe_nr;
3841         u64 stripe_nr_orig;
3842         u64 stripe_nr_end;
3843         int stripe_index;
3844         int i;
3845         int ret = 0;
3846         int num_stripes;
3847         int max_errors = 0;
3848         struct btrfs_bio *bbio = NULL;
3849
3850         read_lock(&em_tree->lock);
3851         em = lookup_extent_mapping(em_tree, logical, *length);
3852         read_unlock(&em_tree->lock);
3853
3854         if (!em) {
3855                 printk(KERN_CRIT "btrfs: unable to find logical %llu len %llu\n",
3856                        (unsigned long long)logical,
3857                        (unsigned long long)*length);
3858                 BUG();
3859         }
3860
3861         BUG_ON(em->start > logical || em->start + em->len < logical);
3862         map = (struct map_lookup *)em->bdev;
3863         offset = logical - em->start;
3864
3865         if (mirror_num > map->num_stripes)
3866                 mirror_num = 0;
3867
3868         stripe_nr = offset;
3869         /*
3870          * stripe_nr counts the total number of stripes we have to stride
3871          * to get to this block
3872          */
3873         do_div(stripe_nr, map->stripe_len);
3874
3875         stripe_offset = stripe_nr * map->stripe_len;
3876         BUG_ON(offset < stripe_offset);
3877
3878         /* stripe_offset is the offset of this block in its stripe*/
3879         stripe_offset = offset - stripe_offset;
3880
3881         if (rw & REQ_DISCARD)
3882                 *length = min_t(u64, em->len - offset, *length);
3883         else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
3884                 /* we limit the length of each bio to what fits in a stripe */
3885                 *length = min_t(u64, em->len - offset,
3886                                 map->stripe_len - stripe_offset);
3887         } else {
3888                 *length = em->len - offset;
3889         }
3890
3891         if (!bbio_ret)
3892                 goto out;
3893
3894         num_stripes = 1;
3895         stripe_index = 0;
3896         stripe_nr_orig = stripe_nr;
3897         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
3898                         (~(map->stripe_len - 1));
3899         do_div(stripe_nr_end, map->stripe_len);
3900         stripe_end_offset = stripe_nr_end * map->stripe_len -
3901                             (offset + *length);
3902         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3903                 if (rw & REQ_DISCARD)
3904                         num_stripes = min_t(u64, map->num_stripes,
3905                                             stripe_nr_end - stripe_nr_orig);
3906                 stripe_index = do_div(stripe_nr, map->num_stripes);
3907         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3908                 if (rw & (REQ_WRITE | REQ_DISCARD))
3909                         num_stripes = map->num_stripes;
3910                 else if (mirror_num)
3911                         stripe_index = mirror_num - 1;
3912                 else {
3913                         stripe_index = find_live_mirror(map, 0,
3914                                             map->num_stripes,
3915                                             current->pid % map->num_stripes);
3916                         mirror_num = stripe_index + 1;
3917                 }
3918
3919         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3920                 if (rw & (REQ_WRITE | REQ_DISCARD)) {
3921                         num_stripes = map->num_stripes;
3922                 } else if (mirror_num) {
3923                         stripe_index = mirror_num - 1;
3924                 } else {
3925                         mirror_num = 1;
3926                 }
3927
3928         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3929                 int factor = map->num_stripes / map->sub_stripes;
3930
3931                 stripe_index = do_div(stripe_nr, factor);
3932                 stripe_index *= map->sub_stripes;
3933
3934                 if (rw & REQ_WRITE)
3935                         num_stripes = map->sub_stripes;
3936                 else if (rw & REQ_DISCARD)
3937                         num_stripes = min_t(u64, map->sub_stripes *
3938                                             (stripe_nr_end - stripe_nr_orig),
3939                                             map->num_stripes);
3940                 else if (mirror_num)
3941                         stripe_index += mirror_num - 1;
3942                 else {
3943                         int old_stripe_index = stripe_index;
3944                         stripe_index = find_live_mirror(map, stripe_index,
3945                                               map->sub_stripes, stripe_index +
3946                                               current->pid % map->sub_stripes);
3947                         mirror_num = stripe_index - old_stripe_index + 1;
3948                 }
3949         } else {
3950                 /*
3951                  * after this do_div call, stripe_nr is the number of stripes
3952                  * on this device we have to walk to find the data, and
3953                  * stripe_index is the number of our device in the stripe array
3954                  */
3955                 stripe_index = do_div(stripe_nr, map->num_stripes);
3956                 mirror_num = stripe_index + 1;
3957         }
3958         BUG_ON(stripe_index >= map->num_stripes);
3959
3960         bbio = kzalloc(btrfs_bio_size(num_stripes), GFP_NOFS);
3961         if (!bbio) {
3962                 ret = -ENOMEM;
3963                 goto out;
3964         }
3965         atomic_set(&bbio->error, 0);
3966
3967         if (rw & REQ_DISCARD) {
3968                 int factor = 0;
3969                 int sub_stripes = 0;
3970                 u64 stripes_per_dev = 0;
3971                 u32 remaining_stripes = 0;
3972                 u32 last_stripe = 0;
3973
3974                 if (map->type &
3975                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
3976                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
3977                                 sub_stripes = 1;
3978                         else
3979                                 sub_stripes = map->sub_stripes;
3980
3981                         factor = map->num_stripes / sub_stripes;
3982                         stripes_per_dev = div_u64_rem(stripe_nr_end -
3983                                                       stripe_nr_orig,
3984                                                       factor,
3985                                                       &remaining_stripes);
3986                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
3987                         last_stripe *= sub_stripes;
3988                 }
3989
3990                 for (i = 0; i < num_stripes; i++) {
3991                         bbio->stripes[i].physical =
3992                                 map->stripes[stripe_index].physical +
3993                                 stripe_offset + stripe_nr * map->stripe_len;
3994                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
3995
3996                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
3997                                          BTRFS_BLOCK_GROUP_RAID10)) {
3998                                 bbio->stripes[i].length = stripes_per_dev *
3999                                                           map->stripe_len;
4000
4001                                 if (i / sub_stripes < remaining_stripes)
4002                                         bbio->stripes[i].length +=
4003                                                 map->stripe_len;
4004
4005                                 /*
4006                                  * Special for the first stripe and
4007                                  * the last stripe:
4008                                  *
4009                                  * |-------|...|-------|
4010                                  *     |----------|
4011                                  *    off     end_off
4012                                  */
4013                                 if (i < sub_stripes)
4014                                         bbio->stripes[i].length -=
4015                                                 stripe_offset;
4016
4017                                 if (stripe_index >= last_stripe &&
4018                                     stripe_index <= (last_stripe +
4019                                                      sub_stripes - 1))
4020                                         bbio->stripes[i].length -=
4021                                                 stripe_end_offset;
4022
4023                                 if (i == sub_stripes - 1)
4024                                         stripe_offset = 0;
4025                         } else
4026                                 bbio->stripes[i].length = *length;
4027
4028                         stripe_index++;
4029                         if (stripe_index == map->num_stripes) {
4030                                 /* This could only happen for RAID0/10 */
4031                                 stripe_index = 0;
4032                                 stripe_nr++;
4033                         }
4034                 }
4035         } else {
4036                 for (i = 0; i < num_stripes; i++) {
4037                         bbio->stripes[i].physical =
4038                                 map->stripes[stripe_index].physical +
4039                                 stripe_offset +
4040                                 stripe_nr * map->stripe_len;
4041                         bbio->stripes[i].dev =
4042                                 map->stripes[stripe_index].dev;
4043                         stripe_index++;
4044                 }
4045         }
4046
4047         if (rw & REQ_WRITE) {
4048                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4049                                  BTRFS_BLOCK_GROUP_RAID10 |
4050                                  BTRFS_BLOCK_GROUP_DUP)) {
4051                         max_errors = 1;
4052                 }
4053         }
4054
4055         *bbio_ret = bbio;
4056         bbio->num_stripes = num_stripes;
4057         bbio->max_errors = max_errors;
4058         bbio->mirror_num = mirror_num;
4059 out:
4060         free_extent_map(em);
4061         return ret;
4062 }
4063
4064 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
4065                       u64 logical, u64 *length,
4066                       struct btrfs_bio **bbio_ret, int mirror_num)
4067 {
4068         return __btrfs_map_block(map_tree, rw, logical, length, bbio_ret,
4069                                  mirror_num);
4070 }
4071
4072 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4073                      u64 chunk_start, u64 physical, u64 devid,
4074                      u64 **logical, int *naddrs, int *stripe_len)
4075 {
4076         struct extent_map_tree *em_tree = &map_tree->map_tree;
4077         struct extent_map *em;
4078         struct map_lookup *map;
4079         u64 *buf;
4080         u64 bytenr;
4081         u64 length;
4082         u64 stripe_nr;
4083         int i, j, nr = 0;
4084
4085         read_lock(&em_tree->lock);
4086         em = lookup_extent_mapping(em_tree, chunk_start, 1);
4087         read_unlock(&em_tree->lock);
4088
4089         BUG_ON(!em || em->start != chunk_start);
4090         map = (struct map_lookup *)em->bdev;
4091
4092         length = em->len;
4093         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4094                 do_div(length, map->num_stripes / map->sub_stripes);
4095         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4096                 do_div(length, map->num_stripes);
4097
4098         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4099         BUG_ON(!buf); /* -ENOMEM */
4100
4101         for (i = 0; i < map->num_stripes; i++) {
4102                 if (devid && map->stripes[i].dev->devid != devid)
4103                         continue;
4104                 if (map->stripes[i].physical > physical ||
4105                     map->stripes[i].physical + length <= physical)
4106                         continue;
4107
4108                 stripe_nr = physical - map->stripes[i].physical;
4109                 do_div(stripe_nr, map->stripe_len);
4110
4111                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4112                         stripe_nr = stripe_nr * map->num_stripes + i;
4113                         do_div(stripe_nr, map->sub_stripes);
4114                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4115                         stripe_nr = stripe_nr * map->num_stripes + i;
4116                 }
4117                 bytenr = chunk_start + stripe_nr * map->stripe_len;
4118                 WARN_ON(nr >= map->num_stripes);
4119                 for (j = 0; j < nr; j++) {
4120                         if (buf[j] == bytenr)
4121                                 break;
4122                 }
4123                 if (j == nr) {
4124                         WARN_ON(nr >= map->num_stripes);
4125                         buf[nr++] = bytenr;
4126                 }
4127         }
4128
4129         *logical = buf;
4130         *naddrs = nr;
4131         *stripe_len = map->stripe_len;
4132
4133         free_extent_map(em);
4134         return 0;
4135 }
4136
4137 static void *merge_stripe_index_into_bio_private(void *bi_private,
4138                                                  unsigned int stripe_index)
4139 {
4140         /*
4141          * with single, dup, RAID0, RAID1 and RAID10, stripe_index is
4142          * at most 1.
4143          * The alternative solution (instead of stealing bits from the
4144          * pointer) would be to allocate an intermediate structure
4145          * that contains the old private pointer plus the stripe_index.
4146          */
4147         BUG_ON((((uintptr_t)bi_private) & 3) != 0);
4148         BUG_ON(stripe_index > 3);
4149         return (void *)(((uintptr_t)bi_private) | stripe_index);
4150 }
4151
4152 static struct btrfs_bio *extract_bbio_from_bio_private(void *bi_private)
4153 {
4154         return (struct btrfs_bio *)(((uintptr_t)bi_private) & ~((uintptr_t)3));
4155 }
4156
4157 static unsigned int extract_stripe_index_from_bio_private(void *bi_private)
4158 {
4159         return (unsigned int)((uintptr_t)bi_private) & 3;
4160 }
4161
4162 static void btrfs_end_bio(struct bio *bio, int err)
4163 {
4164         struct btrfs_bio *bbio = extract_bbio_from_bio_private(bio->bi_private);
4165         int is_orig_bio = 0;
4166
4167         if (err) {
4168                 atomic_inc(&bbio->error);
4169                 if (err == -EIO || err == -EREMOTEIO) {
4170                         unsigned int stripe_index =
4171                                 extract_stripe_index_from_bio_private(
4172                                         bio->bi_private);
4173                         struct btrfs_device *dev;
4174
4175                         BUG_ON(stripe_index >= bbio->num_stripes);
4176                         dev = bbio->stripes[stripe_index].dev;
4177                         if (dev->bdev) {
4178                                 if (bio->bi_rw & WRITE)
4179                                         btrfs_dev_stat_inc(dev,
4180                                                 BTRFS_DEV_STAT_WRITE_ERRS);
4181                                 else
4182                                         btrfs_dev_stat_inc(dev,
4183                                                 BTRFS_DEV_STAT_READ_ERRS);
4184                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
4185                                         btrfs_dev_stat_inc(dev,
4186                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
4187                                 btrfs_dev_stat_print_on_error(dev);
4188                         }
4189                 }
4190         }
4191
4192         if (bio == bbio->orig_bio)
4193                 is_orig_bio = 1;
4194
4195         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4196                 if (!is_orig_bio) {
4197                         bio_put(bio);
4198                         bio = bbio->orig_bio;
4199                 }
4200                 bio->bi_private = bbio->private;
4201                 bio->bi_end_io = bbio->end_io;
4202                 bio->bi_bdev = (struct block_device *)
4203                                         (unsigned long)bbio->mirror_num;
4204                 /* only send an error to the higher layers if it is
4205                  * beyond the tolerance of the multi-bio
4206                  */
4207                 if (atomic_read(&bbio->error) > bbio->max_errors) {
4208                         err = -EIO;
4209                 } else {
4210                         /*
4211                          * this bio is actually up to date, we didn't
4212                          * go over the max number of errors
4213                          */
4214                         set_bit(BIO_UPTODATE, &bio->bi_flags);
4215                         err = 0;
4216                 }
4217                 kfree(bbio);
4218
4219                 bio_endio(bio, err);
4220         } else if (!is_orig_bio) {
4221                 bio_put(bio);
4222         }
4223 }
4224
4225 struct async_sched {
4226         struct bio *bio;
4227         int rw;
4228         struct btrfs_fs_info *info;
4229         struct btrfs_work work;
4230 };
4231
4232 /*
4233  * see run_scheduled_bios for a description of why bios are collected for
4234  * async submit.
4235  *
4236  * This will add one bio to the pending list for a device and make sure
4237  * the work struct is scheduled.
4238  */
4239 static noinline void schedule_bio(struct btrfs_root *root,
4240                                  struct btrfs_device *device,
4241                                  int rw, struct bio *bio)
4242 {
4243         int should_queue = 1;
4244         struct btrfs_pending_bios *pending_bios;
4245
4246         /* don't bother with additional async steps for reads, right now */
4247         if (!(rw & REQ_WRITE)) {
4248                 bio_get(bio);
4249                 btrfsic_submit_bio(rw, bio);
4250                 bio_put(bio);
4251                 return;
4252         }
4253
4254         /*
4255          * nr_async_bios allows us to reliably return congestion to the
4256          * higher layers.  Otherwise, the async bio makes it appear we have
4257          * made progress against dirty pages when we've really just put it
4258          * on a queue for later
4259          */
4260         atomic_inc(&root->fs_info->nr_async_bios);
4261         WARN_ON(bio->bi_next);
4262         bio->bi_next = NULL;
4263         bio->bi_rw |= rw;
4264
4265         spin_lock(&device->io_lock);
4266         if (bio->bi_rw & REQ_SYNC)
4267                 pending_bios = &device->pending_sync_bios;
4268         else
4269                 pending_bios = &device->pending_bios;
4270
4271         if (pending_bios->tail)
4272                 pending_bios->tail->bi_next = bio;
4273
4274         pending_bios->tail = bio;
4275         if (!pending_bios->head)
4276                 pending_bios->head = bio;
4277         if (device->running_pending)
4278                 should_queue = 0;
4279
4280         spin_unlock(&device->io_lock);
4281
4282         if (should_queue)
4283                 btrfs_queue_worker(&root->fs_info->submit_workers,
4284                                    &device->work);
4285 }
4286
4287 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
4288                        sector_t sector)
4289 {
4290         struct bio_vec *prev;
4291         struct request_queue *q = bdev_get_queue(bdev);
4292         unsigned short max_sectors = queue_max_sectors(q);
4293         struct bvec_merge_data bvm = {
4294                 .bi_bdev = bdev,
4295                 .bi_sector = sector,
4296                 .bi_rw = bio->bi_rw,
4297         };
4298
4299         if (bio->bi_vcnt == 0) {
4300                 WARN_ON(1);
4301                 return 1;
4302         }
4303
4304         prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
4305         if ((bio->bi_size >> 9) > max_sectors)
4306                 return 0;
4307
4308         if (!q->merge_bvec_fn)
4309                 return 1;
4310
4311         bvm.bi_size = bio->bi_size - prev->bv_len;
4312         if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
4313                 return 0;
4314         return 1;
4315 }
4316
4317 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4318                               struct bio *bio, u64 physical, int dev_nr,
4319                               int rw, int async)
4320 {
4321         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
4322
4323         bio->bi_private = bbio;
4324         bio->bi_private = merge_stripe_index_into_bio_private(
4325                         bio->bi_private, (unsigned int)dev_nr);
4326         bio->bi_end_io = btrfs_end_bio;
4327         bio->bi_sector = physical >> 9;
4328 #ifdef DEBUG
4329         {
4330                 struct rcu_string *name;
4331
4332                 rcu_read_lock();
4333                 name = rcu_dereference(dev->name);
4334                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
4335                          "(%s id %llu), size=%u\n", rw,
4336                          (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
4337                          name->str, dev->devid, bio->bi_size);
4338                 rcu_read_unlock();
4339         }
4340 #endif
4341         bio->bi_bdev = dev->bdev;
4342         if (async)
4343                 schedule_bio(root, dev, rw, bio);
4344         else
4345                 btrfsic_submit_bio(rw, bio);
4346 }
4347
4348 static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
4349                               struct bio *first_bio, struct btrfs_device *dev,
4350                               int dev_nr, int rw, int async)
4351 {
4352         struct bio_vec *bvec = first_bio->bi_io_vec;
4353         struct bio *bio;
4354         int nr_vecs = bio_get_nr_vecs(dev->bdev);
4355         u64 physical = bbio->stripes[dev_nr].physical;
4356
4357 again:
4358         bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
4359         if (!bio)
4360                 return -ENOMEM;
4361
4362         while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
4363                 if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
4364                                  bvec->bv_offset) < bvec->bv_len) {
4365                         u64 len = bio->bi_size;
4366
4367                         atomic_inc(&bbio->stripes_pending);
4368                         submit_stripe_bio(root, bbio, bio, physical, dev_nr,
4369                                           rw, async);
4370                         physical += len;
4371                         goto again;
4372                 }
4373                 bvec++;
4374         }
4375
4376         submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
4377         return 0;
4378 }
4379
4380 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
4381 {
4382         atomic_inc(&bbio->error);
4383         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4384                 bio->bi_private = bbio->private;
4385                 bio->bi_end_io = bbio->end_io;
4386                 bio->bi_bdev = (struct block_device *)
4387                         (unsigned long)bbio->mirror_num;
4388                 bio->bi_sector = logical >> 9;
4389                 kfree(bbio);
4390                 bio_endio(bio, -EIO);
4391         }
4392 }
4393
4394 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
4395                   int mirror_num, int async_submit)
4396 {
4397         struct btrfs_mapping_tree *map_tree;
4398         struct btrfs_device *dev;
4399         struct bio *first_bio = bio;
4400         u64 logical = (u64)bio->bi_sector << 9;
4401         u64 length = 0;
4402         u64 map_length;
4403         int ret;
4404         int dev_nr = 0;
4405         int total_devs = 1;
4406         struct btrfs_bio *bbio = NULL;
4407
4408         length = bio->bi_size;
4409         map_tree = &root->fs_info->mapping_tree;
4410         map_length = length;
4411
4412         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &bbio,
4413                               mirror_num);
4414         if (ret) /* -ENOMEM */
4415                 return ret;
4416
4417         total_devs = bbio->num_stripes;
4418         if (map_length < length) {
4419                 printk(KERN_CRIT "btrfs: mapping failed logical %llu bio len %llu "
4420                        "len %llu\n", (unsigned long long)logical,
4421                        (unsigned long long)length,
4422                        (unsigned long long)map_length);
4423                 BUG();
4424         }
4425
4426         bbio->orig_bio = first_bio;
4427         bbio->private = first_bio->bi_private;
4428         bbio->end_io = first_bio->bi_end_io;
4429         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
4430
4431         while (dev_nr < total_devs) {
4432                 dev = bbio->stripes[dev_nr].dev;
4433                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
4434                         bbio_error(bbio, first_bio, logical);
4435                         dev_nr++;
4436                         continue;
4437                 }
4438
4439                 /*
4440                  * Check and see if we're ok with this bio based on it's size
4441                  * and offset with the given device.
4442                  */
4443                 if (!bio_size_ok(dev->bdev, first_bio,
4444                                  bbio->stripes[dev_nr].physical >> 9)) {
4445                         ret = breakup_stripe_bio(root, bbio, first_bio, dev,
4446                                                  dev_nr, rw, async_submit);
4447                         BUG_ON(ret);
4448                         dev_nr++;
4449                         continue;
4450                 }
4451
4452                 if (dev_nr < total_devs - 1) {
4453                         bio = bio_clone(first_bio, GFP_NOFS);
4454                         BUG_ON(!bio); /* -ENOMEM */
4455                 } else {
4456                         bio = first_bio;
4457                 }
4458
4459                 submit_stripe_bio(root, bbio, bio,
4460                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
4461                                   async_submit);
4462                 dev_nr++;
4463         }
4464         return 0;
4465 }
4466
4467 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
4468                                        u8 *uuid, u8 *fsid)
4469 {
4470         struct btrfs_device *device;
4471         struct btrfs_fs_devices *cur_devices;
4472
4473         cur_devices = root->fs_info->fs_devices;
4474         while (cur_devices) {
4475                 if (!fsid ||
4476                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4477                         device = __find_device(&cur_devices->devices,
4478                                                devid, uuid);
4479                         if (device)
4480                                 return device;
4481                 }
4482                 cur_devices = cur_devices->seed;
4483         }
4484         return NULL;
4485 }
4486
4487 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
4488                                             u64 devid, u8 *dev_uuid)
4489 {
4490         struct btrfs_device *device;
4491         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4492
4493         device = kzalloc(sizeof(*device), GFP_NOFS);
4494         if (!device)
4495                 return NULL;
4496         list_add(&device->dev_list,
4497                  &fs_devices->devices);
4498         device->dev_root = root->fs_info->dev_root;
4499         device->devid = devid;
4500         device->work.func = pending_bios_fn;
4501         device->fs_devices = fs_devices;
4502         device->missing = 1;
4503         fs_devices->num_devices++;
4504         fs_devices->missing_devices++;
4505         spin_lock_init(&device->io_lock);
4506         INIT_LIST_HEAD(&device->dev_alloc_list);
4507         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
4508         return device;
4509 }
4510
4511 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
4512                           struct extent_buffer *leaf,
4513                           struct btrfs_chunk *chunk)
4514 {
4515         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4516         struct map_lookup *map;
4517         struct extent_map *em;
4518         u64 logical;
4519         u64 length;
4520         u64 devid;
4521         u8 uuid[BTRFS_UUID_SIZE];
4522         int num_stripes;
4523         int ret;
4524         int i;
4525
4526         logical = key->offset;
4527         length = btrfs_chunk_length(leaf, chunk);
4528
4529         read_lock(&map_tree->map_tree.lock);
4530         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
4531         read_unlock(&map_tree->map_tree.lock);
4532
4533         /* already mapped? */
4534         if (em && em->start <= logical && em->start + em->len > logical) {
4535                 free_extent_map(em);
4536                 return 0;
4537         } else if (em) {
4538                 free_extent_map(em);
4539         }
4540
4541         em = alloc_extent_map();
4542         if (!em)
4543                 return -ENOMEM;
4544         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
4545         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4546         if (!map) {
4547                 free_extent_map(em);
4548                 return -ENOMEM;
4549         }
4550
4551         em->bdev = (struct block_device *)map;
4552         em->start = logical;
4553         em->len = length;
4554         em->block_start = 0;
4555         em->block_len = em->len;
4556
4557         map->num_stripes = num_stripes;
4558         map->io_width = btrfs_chunk_io_width(leaf, chunk);
4559         map->io_align = btrfs_chunk_io_align(leaf, chunk);
4560         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
4561         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
4562         map->type = btrfs_chunk_type(leaf, chunk);
4563         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
4564         for (i = 0; i < num_stripes; i++) {
4565                 map->stripes[i].physical =
4566                         btrfs_stripe_offset_nr(leaf, chunk, i);
4567                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
4568                 read_extent_buffer(leaf, uuid, (unsigned long)
4569                                    btrfs_stripe_dev_uuid_nr(chunk, i),
4570                                    BTRFS_UUID_SIZE);
4571                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
4572                                                         NULL);
4573                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
4574                         kfree(map);
4575                         free_extent_map(em);
4576                         return -EIO;
4577                 }
4578                 if (!map->stripes[i].dev) {
4579                         map->stripes[i].dev =
4580                                 add_missing_dev(root, devid, uuid);
4581                         if (!map->stripes[i].dev) {
4582                                 kfree(map);
4583                                 free_extent_map(em);
4584                                 return -EIO;
4585                         }
4586                 }
4587                 map->stripes[i].dev->in_fs_metadata = 1;
4588         }
4589
4590         write_lock(&map_tree->map_tree.lock);
4591         ret = add_extent_mapping(&map_tree->map_tree, em);
4592         write_unlock(&map_tree->map_tree.lock);
4593         BUG_ON(ret); /* Tree corruption */
4594         free_extent_map(em);
4595
4596         return 0;
4597 }
4598
4599 static void fill_device_from_item(struct extent_buffer *leaf,
4600                                  struct btrfs_dev_item *dev_item,
4601                                  struct btrfs_device *device)
4602 {
4603         unsigned long ptr;
4604
4605         device->devid = btrfs_device_id(leaf, dev_item);
4606         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
4607         device->total_bytes = device->disk_total_bytes;
4608         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
4609         device->type = btrfs_device_type(leaf, dev_item);
4610         device->io_align = btrfs_device_io_align(leaf, dev_item);
4611         device->io_width = btrfs_device_io_width(leaf, dev_item);
4612         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
4613
4614         ptr = (unsigned long)btrfs_device_uuid(dev_item);
4615         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
4616 }
4617
4618 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
4619 {
4620         struct btrfs_fs_devices *fs_devices;
4621         int ret;
4622
4623         BUG_ON(!mutex_is_locked(&uuid_mutex));
4624
4625         fs_devices = root->fs_info->fs_devices->seed;
4626         while (fs_devices) {
4627                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4628                         ret = 0;
4629                         goto out;
4630                 }
4631                 fs_devices = fs_devices->seed;
4632         }
4633
4634         fs_devices = find_fsid(fsid);
4635         if (!fs_devices) {
4636                 ret = -ENOENT;
4637                 goto out;
4638         }
4639
4640         fs_devices = clone_fs_devices(fs_devices);
4641         if (IS_ERR(fs_devices)) {
4642                 ret = PTR_ERR(fs_devices);
4643                 goto out;
4644         }
4645
4646         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
4647                                    root->fs_info->bdev_holder);
4648         if (ret) {
4649                 free_fs_devices(fs_devices);
4650                 goto out;
4651         }
4652
4653         if (!fs_devices->seeding) {
4654                 __btrfs_close_devices(fs_devices);
4655                 free_fs_devices(fs_devices);
4656                 ret = -EINVAL;
4657                 goto out;
4658         }
4659
4660         fs_devices->seed = root->fs_info->fs_devices->seed;
4661         root->fs_info->fs_devices->seed = fs_devices;
4662 out:
4663         return ret;
4664 }
4665
4666 static int read_one_dev(struct btrfs_root *root,
4667                         struct extent_buffer *leaf,
4668                         struct btrfs_dev_item *dev_item)
4669 {
4670         struct btrfs_device *device;
4671         u64 devid;
4672         int ret;
4673         u8 fs_uuid[BTRFS_UUID_SIZE];
4674         u8 dev_uuid[BTRFS_UUID_SIZE];
4675
4676         devid = btrfs_device_id(leaf, dev_item);
4677         read_extent_buffer(leaf, dev_uuid,
4678                            (unsigned long)btrfs_device_uuid(dev_item),
4679                            BTRFS_UUID_SIZE);
4680         read_extent_buffer(leaf, fs_uuid,
4681                            (unsigned long)btrfs_device_fsid(dev_item),
4682                            BTRFS_UUID_SIZE);
4683
4684         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
4685                 ret = open_seed_devices(root, fs_uuid);
4686                 if (ret && !btrfs_test_opt(root, DEGRADED))
4687                         return ret;
4688         }
4689
4690         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
4691         if (!device || !device->bdev) {
4692                 if (!btrfs_test_opt(root, DEGRADED))
4693                         return -EIO;
4694
4695                 if (!device) {
4696                         printk(KERN_WARNING "warning devid %llu missing\n",
4697                                (unsigned long long)devid);
4698                         device = add_missing_dev(root, devid, dev_uuid);
4699                         if (!device)
4700                                 return -ENOMEM;
4701                 } else if (!device->missing) {
4702                         /*
4703                          * this happens when a device that was properly setup
4704                          * in the device info lists suddenly goes bad.
4705                          * device->bdev is NULL, and so we have to set
4706                          * device->missing to one here
4707                          */
4708                         root->fs_info->fs_devices->missing_devices++;
4709                         device->missing = 1;
4710                 }
4711         }
4712
4713         if (device->fs_devices != root->fs_info->fs_devices) {
4714                 BUG_ON(device->writeable);
4715                 if (device->generation !=
4716                     btrfs_device_generation(leaf, dev_item))
4717                         return -EINVAL;
4718         }
4719
4720         fill_device_from_item(leaf, dev_item, device);
4721         device->dev_root = root->fs_info->dev_root;
4722         device->in_fs_metadata = 1;
4723         if (device->writeable) {
4724                 device->fs_devices->total_rw_bytes += device->total_bytes;
4725                 spin_lock(&root->fs_info->free_chunk_lock);
4726                 root->fs_info->free_chunk_space += device->total_bytes -
4727                         device->bytes_used;
4728                 spin_unlock(&root->fs_info->free_chunk_lock);
4729         }
4730         ret = 0;
4731         return ret;
4732 }
4733
4734 int btrfs_read_sys_array(struct btrfs_root *root)
4735 {
4736         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4737         struct extent_buffer *sb;
4738         struct btrfs_disk_key *disk_key;
4739         struct btrfs_chunk *chunk;
4740         u8 *ptr;
4741         unsigned long sb_ptr;
4742         int ret = 0;
4743         u32 num_stripes;
4744         u32 array_size;
4745         u32 len = 0;
4746         u32 cur;
4747         struct btrfs_key key;
4748
4749         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
4750                                           BTRFS_SUPER_INFO_SIZE);
4751         if (!sb)
4752                 return -ENOMEM;
4753         btrfs_set_buffer_uptodate(sb);
4754         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
4755         /*
4756          * The sb extent buffer is artifical and just used to read the system array.
4757          * btrfs_set_buffer_uptodate() call does not properly mark all it's
4758          * pages up-to-date when the page is larger: extent does not cover the
4759          * whole page and consequently check_page_uptodate does not find all
4760          * the page's extents up-to-date (the hole beyond sb),
4761          * write_extent_buffer then triggers a WARN_ON.
4762          *
4763          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
4764          * but sb spans only this function. Add an explicit SetPageUptodate call
4765          * to silence the warning eg. on PowerPC 64.
4766          */
4767         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
4768                 SetPageUptodate(sb->pages[0]);
4769
4770         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
4771         array_size = btrfs_super_sys_array_size(super_copy);
4772
4773         ptr = super_copy->sys_chunk_array;
4774         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
4775         cur = 0;
4776
4777         while (cur < array_size) {
4778                 disk_key = (struct btrfs_disk_key *)ptr;
4779                 btrfs_disk_key_to_cpu(&key, disk_key);
4780
4781                 len = sizeof(*disk_key); ptr += len;
4782                 sb_ptr += len;
4783                 cur += len;
4784
4785                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
4786                         chunk = (struct btrfs_chunk *)sb_ptr;
4787                         ret = read_one_chunk(root, &key, sb, chunk);
4788                         if (ret)
4789                                 break;
4790                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
4791                         len = btrfs_chunk_item_size(num_stripes);
4792                 } else {
4793                         ret = -EIO;
4794                         break;
4795                 }
4796                 ptr += len;
4797                 sb_ptr += len;
4798                 cur += len;
4799         }
4800         free_extent_buffer(sb);
4801         return ret;
4802 }
4803
4804 int btrfs_read_chunk_tree(struct btrfs_root *root)
4805 {
4806         struct btrfs_path *path;
4807         struct extent_buffer *leaf;
4808         struct btrfs_key key;
4809         struct btrfs_key found_key;
4810         int ret;
4811         int slot;
4812
4813         root = root->fs_info->chunk_root;
4814
4815         path = btrfs_alloc_path();
4816         if (!path)
4817                 return -ENOMEM;
4818
4819         mutex_lock(&uuid_mutex);
4820         lock_chunks(root);
4821
4822         /* first we search for all of the device items, and then we
4823          * read in all of the chunk items.  This way we can create chunk
4824          * mappings that reference all of the devices that are afound
4825          */
4826         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
4827         key.offset = 0;
4828         key.type = 0;
4829 again:
4830         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4831         if (ret < 0)
4832                 goto error;
4833         while (1) {
4834                 leaf = path->nodes[0];
4835                 slot = path->slots[0];
4836                 if (slot >= btrfs_header_nritems(leaf)) {
4837                         ret = btrfs_next_leaf(root, path);
4838                         if (ret == 0)
4839                                 continue;
4840                         if (ret < 0)
4841                                 goto error;
4842                         break;
4843                 }
4844                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4845                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
4846                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
4847                                 break;
4848                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
4849                                 struct btrfs_dev_item *dev_item;
4850                                 dev_item = btrfs_item_ptr(leaf, slot,
4851                                                   struct btrfs_dev_item);
4852                                 ret = read_one_dev(root, leaf, dev_item);
4853                                 if (ret)
4854                                         goto error;
4855                         }
4856                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
4857                         struct btrfs_chunk *chunk;
4858                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
4859                         ret = read_one_chunk(root, &found_key, leaf, chunk);
4860                         if (ret)
4861                                 goto error;
4862                 }
4863                 path->slots[0]++;
4864         }
4865         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
4866                 key.objectid = 0;
4867                 btrfs_release_path(path);
4868                 goto again;
4869         }
4870         ret = 0;
4871 error:
4872         unlock_chunks(root);
4873         mutex_unlock(&uuid_mutex);
4874
4875         btrfs_free_path(path);
4876         return ret;
4877 }
4878
4879 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
4880 {
4881         int i;
4882
4883         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4884                 btrfs_dev_stat_reset(dev, i);
4885 }
4886
4887 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
4888 {
4889         struct btrfs_key key;
4890         struct btrfs_key found_key;
4891         struct btrfs_root *dev_root = fs_info->dev_root;
4892         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
4893         struct extent_buffer *eb;
4894         int slot;
4895         int ret = 0;
4896         struct btrfs_device *device;
4897         struct btrfs_path *path = NULL;
4898         int i;
4899
4900         path = btrfs_alloc_path();
4901         if (!path) {
4902                 ret = -ENOMEM;
4903                 goto out;
4904         }
4905
4906         mutex_lock(&fs_devices->device_list_mutex);
4907         list_for_each_entry(device, &fs_devices->devices, dev_list) {
4908                 int item_size;
4909                 struct btrfs_dev_stats_item *ptr;
4910
4911                 key.objectid = 0;
4912                 key.type = BTRFS_DEV_STATS_KEY;
4913                 key.offset = device->devid;
4914                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
4915                 if (ret) {
4916                         __btrfs_reset_dev_stats(device);
4917                         device->dev_stats_valid = 1;
4918                         btrfs_release_path(path);
4919                         continue;
4920                 }
4921                 slot = path->slots[0];
4922                 eb = path->nodes[0];
4923                 btrfs_item_key_to_cpu(eb, &found_key, slot);
4924                 item_size = btrfs_item_size_nr(eb, slot);
4925
4926                 ptr = btrfs_item_ptr(eb, slot,
4927                                      struct btrfs_dev_stats_item);
4928
4929                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
4930                         if (item_size >= (1 + i) * sizeof(__le64))
4931                                 btrfs_dev_stat_set(device, i,
4932                                         btrfs_dev_stats_value(eb, ptr, i));
4933                         else
4934                                 btrfs_dev_stat_reset(device, i);
4935                 }
4936
4937                 device->dev_stats_valid = 1;
4938                 btrfs_dev_stat_print_on_load(device);
4939                 btrfs_release_path(path);
4940         }
4941         mutex_unlock(&fs_devices->device_list_mutex);
4942
4943 out:
4944         btrfs_free_path(path);
4945         return ret < 0 ? ret : 0;
4946 }
4947
4948 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
4949                                 struct btrfs_root *dev_root,
4950                                 struct btrfs_device *device)
4951 {
4952         struct btrfs_path *path;
4953         struct btrfs_key key;
4954         struct extent_buffer *eb;
4955         struct btrfs_dev_stats_item *ptr;
4956         int ret;
4957         int i;
4958
4959         key.objectid = 0;
4960         key.type = BTRFS_DEV_STATS_KEY;
4961         key.offset = device->devid;
4962
4963         path = btrfs_alloc_path();
4964         BUG_ON(!path);
4965         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
4966         if (ret < 0) {
4967                 printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
4968                               ret, rcu_str_deref(device->name));
4969                 goto out;
4970         }
4971
4972         if (ret == 0 &&
4973             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
4974                 /* need to delete old one and insert a new one */
4975                 ret = btrfs_del_item(trans, dev_root, path);
4976                 if (ret != 0) {
4977                         printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
4978                                       rcu_str_deref(device->name), ret);
4979                         goto out;
4980                 }
4981                 ret = 1;
4982         }
4983
4984         if (ret == 1) {
4985                 /* need to insert a new item */
4986                 btrfs_release_path(path);
4987                 ret = btrfs_insert_empty_item(trans, dev_root, path,
4988                                               &key, sizeof(*ptr));
4989                 if (ret < 0) {
4990                         printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
4991                                       rcu_str_deref(device->name), ret);
4992                         goto out;
4993                 }
4994         }
4995
4996         eb = path->nodes[0];
4997         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
4998         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4999                 btrfs_set_dev_stats_value(eb, ptr, i,
5000                                           btrfs_dev_stat_read(device, i));
5001         btrfs_mark_buffer_dirty(eb);
5002
5003 out:
5004         btrfs_free_path(path);
5005         return ret;
5006 }
5007
5008 /*
5009  * called from commit_transaction. Writes all changed device stats to disk.
5010  */
5011 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
5012                         struct btrfs_fs_info *fs_info)
5013 {
5014         struct btrfs_root *dev_root = fs_info->dev_root;
5015         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5016         struct btrfs_device *device;
5017         int ret = 0;
5018
5019         mutex_lock(&fs_devices->device_list_mutex);
5020         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5021                 if (!device->dev_stats_valid || !device->dev_stats_dirty)
5022                         continue;
5023
5024                 ret = update_dev_stat_item(trans, dev_root, device);
5025                 if (!ret)
5026                         device->dev_stats_dirty = 0;
5027         }
5028         mutex_unlock(&fs_devices->device_list_mutex);
5029
5030         return ret;
5031 }
5032
5033 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
5034 {
5035         btrfs_dev_stat_inc(dev, index);
5036         btrfs_dev_stat_print_on_error(dev);
5037 }
5038
5039 void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
5040 {
5041         if (!dev->dev_stats_valid)
5042                 return;
5043         printk_ratelimited_in_rcu(KERN_ERR
5044                            "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5045                            rcu_str_deref(dev->name),
5046                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5047                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5048                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5049                            btrfs_dev_stat_read(dev,
5050                                                BTRFS_DEV_STAT_CORRUPTION_ERRS),
5051                            btrfs_dev_stat_read(dev,
5052                                                BTRFS_DEV_STAT_GENERATION_ERRS));
5053 }
5054
5055 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
5056 {
5057         int i;
5058
5059         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5060                 if (btrfs_dev_stat_read(dev, i) != 0)
5061                         break;
5062         if (i == BTRFS_DEV_STAT_VALUES_MAX)
5063                 return; /* all values == 0, suppress message */
5064
5065         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5066                rcu_str_deref(dev->name),
5067                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5068                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5069                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5070                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
5071                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
5072 }
5073
5074 int btrfs_get_dev_stats(struct btrfs_root *root,
5075                         struct btrfs_ioctl_get_dev_stats *stats)
5076 {
5077         struct btrfs_device *dev;
5078         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5079         int i;
5080
5081         mutex_lock(&fs_devices->device_list_mutex);
5082         dev = btrfs_find_device(root, stats->devid, NULL, NULL);
5083         mutex_unlock(&fs_devices->device_list_mutex);
5084
5085         if (!dev) {
5086                 printk(KERN_WARNING
5087                        "btrfs: get dev_stats failed, device not found\n");
5088                 return -ENODEV;
5089         } else if (!dev->dev_stats_valid) {
5090                 printk(KERN_WARNING
5091                        "btrfs: get dev_stats failed, not yet valid\n");
5092                 return -ENODEV;
5093         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
5094                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5095                         if (stats->nr_items > i)
5096                                 stats->values[i] =
5097                                         btrfs_dev_stat_read_and_reset(dev, i);
5098                         else
5099                                 btrfs_dev_stat_reset(dev, i);
5100                 }
5101         } else {
5102                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5103                         if (stats->nr_items > i)
5104                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
5105         }
5106         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
5107                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
5108         return 0;
5109 }