fs/btrfs/sysfs.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
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/completion.h>
  23 #include <linux/buffer_head.h>
  24 #include <linux/kobject.h>
  25 #include <linux/bug.h>
  26
  27 #include "ctree.h"
  28 #include "disk-io.h"
  29 #include "transaction.h"
  30 #include "sysfs.h"
  31
  32 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  33
  34 static u64 get_features(struct btrfs_fs_info *fs_info,
  35                         enum btrfs_feature_set set)
  36 {
  37         struct btrfs_super_block *disk_super = fs_info->super_copy;
  38         if (set == FEAT_COMPAT)
  39                 return btrfs_super_compat_flags(disk_super);
  40         else if (set == FEAT_COMPAT_RO)
  41                 return btrfs_super_compat_ro_flags(disk_super);
  42         else
  43                 return btrfs_super_incompat_flags(disk_super);
  44 }
  45
  46 static void set_features(struct btrfs_fs_info *fs_info,
  47                          enum btrfs_feature_set set, u64 features)
  48 {
  49         struct btrfs_super_block *disk_super = fs_info->super_copy;
  50         if (set == FEAT_COMPAT)
  51                 btrfs_set_super_compat_flags(disk_super, features);
  52         else if (set == FEAT_COMPAT_RO)
  53                 btrfs_set_super_compat_ro_flags(disk_super, features);
  54         else
  55                 btrfs_set_super_incompat_flags(disk_super, features);
  56 }
  57
  58 static int can_modify_feature(struct btrfs_feature_attr *fa)
  59 {
  60         int val = 0;
  61         u64 set, clear;
  62         switch (fa->feature_set) {
  63         case FEAT_COMPAT:
  64                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  65                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  66                 break;
  67         case FEAT_COMPAT_RO:
  68                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  69                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  70                 break;
  71         case FEAT_INCOMPAT:
  72                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  73                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  74                 break;
  75         default:
  76                 BUG();
  77         }
  78
  79         if (set & fa->feature_bit)
  80                 val |= 1;
  81         if (clear & fa->feature_bit)
  82                 val |= 2;
  83
  84         return val;
  85 }
  86
  87 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  88                                        struct kobj_attribute *a, char *buf)
  89 {
  90         int val = 0;
  91         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  92         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  93         if (fs_info) {
  94                 u64 features = get_features(fs_info, fa->feature_set);
  95                 if (features & fa->feature_bit)
  96                         val = 1;
  97         } else
  98                 val = can_modify_feature(fa);
  99
 100         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 101 }
 102
 103 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 104                                         struct kobj_attribute *a,
 105                                         const char *buf, size_t count)
 106 {
 107         struct btrfs_fs_info *fs_info;
 108         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 109         struct btrfs_trans_handle *trans;
 110         u64 features, set, clear;
 111         unsigned long val;
 112         int ret;
 113
 114         fs_info = to_fs_info(kobj);
 115         if (!fs_info)
 116                 return -EPERM;
 117
 118         ret = kstrtoul(skip_spaces(buf), 0, &val);
 119         if (ret)
 120                 return ret;
 121
 122         if (fa->feature_set == FEAT_COMPAT) {
 123                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 124                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 125         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 126                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 127                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 128         } else {
 129                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 130                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 131         }
 132
 133         features = get_features(fs_info, fa->feature_set);
 134
 135         /* Nothing to do */
 136         if ((val && (features & fa->feature_bit)) ||
 137             (!val && !(features & fa->feature_bit)))
 138                 return count;
 139
 140         if ((val && !(set & fa->feature_bit)) ||
 141             (!val && !(clear & fa->feature_bit))) {
 142                 btrfs_info(fs_info,
 143                         "%sabling feature %s on mounted fs is not supported.",
 144                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 145                 return -EPERM;
 146         }
 147
 148         btrfs_info(fs_info, "%s %s feature flag",
 149                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 150
 151         trans = btrfs_start_transaction(fs_info->fs_root, 1);
 152         if (IS_ERR(trans))
 153                 return PTR_ERR(trans);
 154
 155         spin_lock(&fs_info->super_lock);
 156         features = get_features(fs_info, fa->feature_set);
 157         if (val)
 158                 features |= fa->feature_bit;
 159         else
 160                 features &= ~fa->feature_bit;
 161         set_features(fs_info, fa->feature_set, features);
 162         spin_unlock(&fs_info->super_lock);
 163
 164         ret = btrfs_commit_transaction(trans, fs_info->fs_root);
 165         if (ret)
 166                 return ret;
 167
 168         return count;
 169 }
 170
 171 static umode_t btrfs_feature_visible(struct kobject *kobj,
 172                                      struct attribute *attr, int unused)
 173 {
 174         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 175         umode_t mode = attr->mode;
 176
 177         if (fs_info) {
 178                 struct btrfs_feature_attr *fa;
 179                 u64 features;
 180
 181                 fa = attr_to_btrfs_feature_attr(attr);
 182                 features = get_features(fs_info, fa->feature_set);
 183
 184                 if (can_modify_feature(fa))
 185                         mode |= S_IWUSR;
 186                 else if (!(features & fa->feature_bit))
 187                         mode = 0;
 188         }
 189
 190         return mode;
 191 }
 192
 193 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 194 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 195 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 196 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 197 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzov2, COMPRESS_LZOv2);
 198 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 199 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 200 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 201 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 202
 203 static struct attribute *btrfs_supported_feature_attrs[] = {
 204         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 205         BTRFS_FEAT_ATTR_PTR(default_subvol),
 206         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 207         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 208         BTRFS_FEAT_ATTR_PTR(compress_lzov2),
 209         BTRFS_FEAT_ATTR_PTR(big_metadata),
 210         BTRFS_FEAT_ATTR_PTR(extended_iref),
 211         BTRFS_FEAT_ATTR_PTR(raid56),
 212         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 213         NULL
 214 };
 215
 216 static const struct attribute_group btrfs_feature_attr_group = {
 217         .name = "features",
 218         .is_visible = btrfs_feature_visible,
 219         .attrs = btrfs_supported_feature_attrs,
 220 };
 221
 222 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 223 {
 224         u64 val;
 225         if (lock)
 226                 spin_lock(lock);
 227         val = *value_ptr;
 228         if (lock)
 229                 spin_unlock(lock);
 230         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 231 }
 232
 233 static ssize_t global_rsv_size_show(struct kobject *kobj,
 234                                     struct kobj_attribute *ka, char *buf)
 235 {
 236         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 237         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 238         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 239 }
 240 BTRFS_ATTR(global_rsv_size, 0444, global_rsv_size_show);
 241
 242 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 243                                         struct kobj_attribute *a, char *buf)
 244 {
 245         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 246         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 247         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 248 }
 249 BTRFS_ATTR(global_rsv_reserved, 0444, global_rsv_reserved_show);
 250
 251 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 252
 253 static ssize_t raid_bytes_show(struct kobject *kobj,
 254                                struct kobj_attribute *attr, char *buf);
 255 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 256 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 257
 258 static ssize_t raid_bytes_show(struct kobject *kobj,
 259                                struct kobj_attribute *attr, char *buf)
 260
 261 {
 262         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 263         struct btrfs_block_group_cache *block_group;
 264         int index = kobj - sinfo->block_group_kobjs;
 265         u64 val = 0;
 266
 267         down_read(&sinfo->groups_sem);
 268         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 269                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
 270                         val += block_group->key.offset;
 271                 else
 272                         val += btrfs_block_group_used(&block_group->item);
 273         }
 274         up_read(&sinfo->groups_sem);
 275         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 276 }
 277
 278 static struct attribute *raid_attributes[] = {
 279         BTRFS_RAID_ATTR_PTR(total_bytes),
 280         BTRFS_RAID_ATTR_PTR(used_bytes),
 281         NULL
 282 };
 283
 284 static void release_raid_kobj(struct kobject *kobj)
 285 {
 286         kobject_put(kobj->parent);
 287 }
 288
 289 struct kobj_type btrfs_raid_ktype = {
 290         .sysfs_ops = &kobj_sysfs_ops,
 291         .release = release_raid_kobj,
 292         .default_attrs = raid_attributes,
 293 };
 294
 295 #define SPACE_INFO_ATTR(field)                                          \
 296 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 297                                              struct kobj_attribute *a,  \
 298                                              char *buf)                 \
 299 {                                                                       \
 300         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 301         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 302 }                                                                       \
 303 BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
 304
 305 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 306                                                        struct kobj_attribute *a,
 307                                                        char *buf)
 308 {
 309         struct btrfs_space_info *sinfo = to_space_info(kobj);
 310         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 311         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 312 }
 313
 314 SPACE_INFO_ATTR(flags);
 315 SPACE_INFO_ATTR(total_bytes);
 316 SPACE_INFO_ATTR(bytes_used);
 317 SPACE_INFO_ATTR(bytes_pinned);
 318 SPACE_INFO_ATTR(bytes_reserved);
 319 SPACE_INFO_ATTR(bytes_may_use);
 320 SPACE_INFO_ATTR(disk_used);
 321 SPACE_INFO_ATTR(disk_total);
 322 BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
 323
 324 static struct attribute *space_info_attrs[] = {
 325         BTRFS_ATTR_PTR(flags),
 326         BTRFS_ATTR_PTR(total_bytes),
 327         BTRFS_ATTR_PTR(bytes_used),
 328         BTRFS_ATTR_PTR(bytes_pinned),
 329         BTRFS_ATTR_PTR(bytes_reserved),
 330         BTRFS_ATTR_PTR(bytes_may_use),
 331         BTRFS_ATTR_PTR(disk_used),
 332         BTRFS_ATTR_PTR(disk_total),
 333         BTRFS_ATTR_PTR(total_bytes_pinned),
 334         NULL,
 335 };
 336
 337 static void space_info_release(struct kobject *kobj)
 338 {
 339         struct btrfs_space_info *sinfo = to_space_info(kobj);
 340         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 341         kfree(sinfo);
 342 }
 343
 344 struct kobj_type space_info_ktype = {
 345         .sysfs_ops = &kobj_sysfs_ops,
 346         .release = space_info_release,
 347         .default_attrs = space_info_attrs,
 348 };
 349
 350 static const struct attribute *allocation_attrs[] = {
 351         BTRFS_ATTR_PTR(global_rsv_reserved),
 352         BTRFS_ATTR_PTR(global_rsv_size),
 353         NULL,
 354 };
 355
 356 static void btrfs_release_super_kobj(struct kobject *kobj)
 357 {
 358         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 359         complete(&fs_info->kobj_unregister);
 360 }
 361
 362 static struct kobj_type btrfs_ktype = {
 363         .sysfs_ops      = &kobj_sysfs_ops,
 364         .release        = btrfs_release_super_kobj,
 365 };
 366
 367 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 368 {
 369         if (kobj->ktype != &btrfs_ktype)
 370                 return NULL;
 371         return container_of(kobj, struct btrfs_fs_info, super_kobj);
 372 }
 373
 374 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 375 {
 376         sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 377         kobject_del(fs_info->space_info_kobj);
 378         kobject_put(fs_info->space_info_kobj);
 379         kobject_del(&fs_info->super_kobj);
 380         kobject_put(&fs_info->super_kobj);
 381         wait_for_completion(&fs_info->kobj_unregister);
 382 }
 383
 384 const char * const btrfs_feature_set_names[3] = {
 385         [FEAT_COMPAT]    = "compat",
 386         [FEAT_COMPAT_RO] = "compat_ro",
 387         [FEAT_INCOMPAT]  = "incompat",
 388 };
 389
 390 #define NUM_FEATURE_BITS 64
 391 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 392 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 393
 394 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 395 {
 396         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 397         int len = 0;
 398         int i;
 399         char *str;
 400
 401         str = kmalloc(bufsize, GFP_KERNEL);
 402         if (!str)
 403                 return str;
 404
 405         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 406                 const char *name;
 407
 408                 if (!(flags & (1ULL << i)))
 409                         continue;
 410
 411                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 412                 len += snprintf(str + len, bufsize - len, "%s%s",
 413                                 len ? "," : "", name);
 414         }
 415
 416         return str;
 417 }
 418
 419 static void init_feature_attrs(void)
 420 {
 421         struct btrfs_feature_attr *fa;
 422         int set, i;
 423
 424         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 425                      ARRAY_SIZE(btrfs_feature_attrs));
 426         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 427                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 428
 429         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 430         memset(btrfs_unknown_feature_names, 0,
 431                sizeof(btrfs_unknown_feature_names));
 432
 433         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 434                 struct btrfs_feature_attr *sfa;
 435                 struct attribute *a = btrfs_supported_feature_attrs[i];
 436                 int bit;
 437                 sfa = attr_to_btrfs_feature_attr(a);
 438                 bit = ilog2(sfa->feature_bit);
 439                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 440
 441                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 442         }
 443
 444         for (set = 0; set < FEAT_MAX; set++) {
 445                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 446                         char *name = btrfs_unknown_feature_names[set][i];
 447                         fa = &btrfs_feature_attrs[set][i];
 448
 449                         if (fa->kobj_attr.attr.name)
 450                                 continue;
 451
 452                         snprintf(name, 13, "%s:%u",
 453                                  btrfs_feature_set_names[set], i);
 454
 455                         fa->kobj_attr.attr.name = name;
 456                         fa->kobj_attr.attr.mode = S_IRUGO;
 457                         fa->feature_set = set;
 458                         fa->feature_bit = 1ULL << i;
 459                 }
 460         }
 461 }
 462
 463 static u64 supported_feature_masks[3] = {
 464         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 465         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 466         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 467 };
 468
 469 static int add_unknown_feature_attrs(struct btrfs_fs_info *fs_info)
 470 {
 471         int set;
 472
 473         for (set = 0; set < FEAT_MAX; set++) {
 474                 int i, count, ret, index = 0;
 475                 struct attribute **attrs;
 476                 struct attribute_group agroup = {
 477                         .name = "features",
 478                 };
 479                 u64 features = get_features(fs_info, set);
 480                 features &= ~supported_feature_masks[set];
 481
 482                 count = hweight64(features);
 483
 484                 if (!count)
 485                         continue;
 486
 487                 attrs = kcalloc(count + 1, sizeof(void *), GFP_KERNEL);
 488
 489                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 490                         struct btrfs_feature_attr *fa;
 491
 492                         if (!(features & (1ULL << i)))
 493                                 continue;
 494
 495                         fa = &btrfs_feature_attrs[set][i];
 496                         attrs[index++] = &fa->kobj_attr.attr;
 497                 }
 498
 499                 attrs[index] = NULL;
 500                 agroup.attrs = attrs;
 501
 502                 ret = sysfs_merge_group(&fs_info->super_kobj, &agroup);
 503                 kfree(attrs);
 504                 if (ret)
 505                         return ret;
 506         }
 507         return 0;
 508 }
 509
 510 /* /sys/fs/btrfs/ entry */
 511 static struct kset *btrfs_kset;
 512
 513 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 514 {
 515         int error;
 516
 517         init_completion(&fs_info->kobj_unregister);
 518         fs_info->super_kobj.kset = btrfs_kset;
 519         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 520                                      "%pU", fs_info->fsid);
 521
 522         error = sysfs_create_group(&fs_info->super_kobj,
 523                                    &btrfs_feature_attr_group);
 524         if (error)
 525                 goto failure;
 526
 527         error = add_unknown_feature_attrs(fs_info);
 528         if (error)
 529                 goto failure;
 530
 531         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 532                                                   &fs_info->super_kobj);
 533         if (!fs_info->space_info_kobj) {
 534                 error = -ENOMEM;
 535                 goto failure;
 536         }
 537
 538         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 539         if (error)
 540                 goto failure;
 541
 542         return 0;
 543 failure:
 544         btrfs_sysfs_remove_one(fs_info);
 545         return error;
 546 }
 547
 548 int btrfs_init_sysfs(void)
 549 {
 550         int ret;
 551         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 552         if (!btrfs_kset)
 553                 return -ENOMEM;
 554
 555         init_feature_attrs();
 556
 557         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 558         if (ret) {
 559                 kset_unregister(btrfs_kset);
 560                 return ret;
 561         }
 562
 563         return 0;
 564 }
 565
 566 void btrfs_exit_sysfs(void)
 567 {
 568         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 569         kset_unregister(btrfs_kset);
 570 }
 571