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 #include <linux/genhd.h>
  27
  28 #include "ctree.h"
  29 #include "disk-io.h"
  30 #include "transaction.h"
  31 #include "sysfs.h"
  32 #include "volumes.h"
  33
  34 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  35
  36 static u64 get_features(struct btrfs_fs_info *fs_info,
  37                         enum btrfs_feature_set set)
  38 {
  39         struct btrfs_super_block *disk_super = fs_info->super_copy;
  40         if (set == FEAT_COMPAT)
  41                 return btrfs_super_compat_flags(disk_super);
  42         else if (set == FEAT_COMPAT_RO)
  43                 return btrfs_super_compat_ro_flags(disk_super);
  44         else
  45                 return btrfs_super_incompat_flags(disk_super);
  46 }
  47
  48 static void set_features(struct btrfs_fs_info *fs_info,
  49                          enum btrfs_feature_set set, u64 features)
  50 {
  51         struct btrfs_super_block *disk_super = fs_info->super_copy;
  52         if (set == FEAT_COMPAT)
  53                 btrfs_set_super_compat_flags(disk_super, features);
  54         else if (set == FEAT_COMPAT_RO)
  55                 btrfs_set_super_compat_ro_flags(disk_super, features);
  56         else
  57                 btrfs_set_super_incompat_flags(disk_super, features);
  58 }
  59
  60 static int can_modify_feature(struct btrfs_feature_attr *fa)
  61 {
  62         int val = 0;
  63         u64 set, clear;
  64         switch (fa->feature_set) {
  65         case FEAT_COMPAT:
  66                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  67                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  68                 break;
  69         case FEAT_COMPAT_RO:
  70                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  71                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  72                 break;
  73         case FEAT_INCOMPAT:
  74                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  75                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  76                 break;
  77         default:
  78                 printk(KERN_WARNING "btrfs: sysfs: unknown feature set %d\n",
  79                                 fa->feature_set);
  80                 return 0;
  81         }
  82
  83         if (set & fa->feature_bit)
  84                 val |= 1;
  85         if (clear & fa->feature_bit)
  86                 val |= 2;
  87
  88         return val;
  89 }
  90
  91 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  92                                        struct kobj_attribute *a, char *buf)
  93 {
  94         int val = 0;
  95         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  96         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  97         if (fs_info) {
  98                 u64 features = get_features(fs_info, fa->feature_set);
  99                 if (features & fa->feature_bit)
 100                         val = 1;
 101         } else
 102                 val = can_modify_feature(fa);
 103
 104         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 105 }
 106
 107 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 108                                         struct kobj_attribute *a,
 109                                         const char *buf, size_t count)
 110 {
 111         struct btrfs_fs_info *fs_info;
 112         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 113         struct btrfs_trans_handle *trans;
 114         u64 features, set, clear;
 115         unsigned long val;
 116         int ret;
 117
 118         fs_info = to_fs_info(kobj);
 119         if (!fs_info)
 120                 return -EPERM;
 121
 122         ret = kstrtoul(skip_spaces(buf), 0, &val);
 123         if (ret)
 124                 return ret;
 125
 126         if (fa->feature_set == FEAT_COMPAT) {
 127                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 128                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 129         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 130                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 131                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 132         } else {
 133                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 134                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 135         }
 136
 137         features = get_features(fs_info, fa->feature_set);
 138
 139         /* Nothing to do */
 140         if ((val && (features & fa->feature_bit)) ||
 141             (!val && !(features & fa->feature_bit)))
 142                 return count;
 143
 144         if ((val && !(set & fa->feature_bit)) ||
 145             (!val && !(clear & fa->feature_bit))) {
 146                 btrfs_info(fs_info,
 147                         "%sabling feature %s on mounted fs is not supported.",
 148                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 149                 return -EPERM;
 150         }
 151
 152         btrfs_info(fs_info, "%s %s feature flag",
 153                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 154
 155         trans = btrfs_start_transaction(fs_info->fs_root, 0);
 156         if (IS_ERR(trans))
 157                 return PTR_ERR(trans);
 158
 159         spin_lock(&fs_info->super_lock);
 160         features = get_features(fs_info, fa->feature_set);
 161         if (val)
 162                 features |= fa->feature_bit;
 163         else
 164                 features &= ~fa->feature_bit;
 165         set_features(fs_info, fa->feature_set, features);
 166         spin_unlock(&fs_info->super_lock);
 167
 168         ret = btrfs_commit_transaction(trans, fs_info->fs_root);
 169         if (ret)
 170                 return ret;
 171
 172         return count;
 173 }
 174
 175 static umode_t btrfs_feature_visible(struct kobject *kobj,
 176                                      struct attribute *attr, int unused)
 177 {
 178         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 179         umode_t mode = attr->mode;
 180
 181         if (fs_info) {
 182                 struct btrfs_feature_attr *fa;
 183                 u64 features;
 184
 185                 fa = attr_to_btrfs_feature_attr(attr);
 186                 features = get_features(fs_info, fa->feature_set);
 187
 188                 if (can_modify_feature(fa))
 189                         mode |= S_IWUSR;
 190                 else if (!(features & fa->feature_bit))
 191                         mode = 0;
 192         }
 193
 194         return mode;
 195 }
 196
 197 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 198 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 199 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 200 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 201 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 202 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 203 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 204 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 205 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 206
 207 static struct attribute *btrfs_supported_feature_attrs[] = {
 208         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 209         BTRFS_FEAT_ATTR_PTR(default_subvol),
 210         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 211         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 212         BTRFS_FEAT_ATTR_PTR(big_metadata),
 213         BTRFS_FEAT_ATTR_PTR(extended_iref),
 214         BTRFS_FEAT_ATTR_PTR(raid56),
 215         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 216         BTRFS_FEAT_ATTR_PTR(no_holes),
 217         NULL
 218 };
 219
 220 static const struct attribute_group btrfs_feature_attr_group = {
 221         .name = "features",
 222         .is_visible = btrfs_feature_visible,
 223         .attrs = btrfs_supported_feature_attrs,
 224 };
 225
 226 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 227 {
 228         u64 val;
 229         if (lock)
 230                 spin_lock(lock);
 231         val = *value_ptr;
 232         if (lock)
 233                 spin_unlock(lock);
 234         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 235 }
 236
 237 static ssize_t global_rsv_size_show(struct kobject *kobj,
 238                                     struct kobj_attribute *ka, char *buf)
 239 {
 240         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 241         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 242         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 243 }
 244 BTRFS_ATTR(global_rsv_size, 0444, global_rsv_size_show);
 245
 246 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 247                                         struct kobj_attribute *a, char *buf)
 248 {
 249         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 250         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 251         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 252 }
 253 BTRFS_ATTR(global_rsv_reserved, 0444, global_rsv_reserved_show);
 254
 255 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 256
 257 static ssize_t raid_bytes_show(struct kobject *kobj,
 258                                struct kobj_attribute *attr, char *buf);
 259 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 260 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 261
 262 static ssize_t raid_bytes_show(struct kobject *kobj,
 263                                struct kobj_attribute *attr, char *buf)
 264
 265 {
 266         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 267         struct btrfs_block_group_cache *block_group;
 268         int index = kobj - sinfo->block_group_kobjs;
 269         u64 val = 0;
 270
 271         down_read(&sinfo->groups_sem);
 272         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 273                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
 274                         val += block_group->key.offset;
 275                 else
 276                         val += btrfs_block_group_used(&block_group->item);
 277         }
 278         up_read(&sinfo->groups_sem);
 279         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 280 }
 281
 282 static struct attribute *raid_attributes[] = {
 283         BTRFS_RAID_ATTR_PTR(total_bytes),
 284         BTRFS_RAID_ATTR_PTR(used_bytes),
 285         NULL
 286 };
 287
 288 static void release_raid_kobj(struct kobject *kobj)
 289 {
 290         kobject_put(kobj->parent);
 291 }
 292
 293 struct kobj_type btrfs_raid_ktype = {
 294         .sysfs_ops = &kobj_sysfs_ops,
 295         .release = release_raid_kobj,
 296         .default_attrs = raid_attributes,
 297 };
 298
 299 #define SPACE_INFO_ATTR(field)                                          \
 300 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 301                                              struct kobj_attribute *a,  \
 302                                              char *buf)                 \
 303 {                                                                       \
 304         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 305         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 306 }                                                                       \
 307 BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
 308
 309 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 310                                                        struct kobj_attribute *a,
 311                                                        char *buf)
 312 {
 313         struct btrfs_space_info *sinfo = to_space_info(kobj);
 314         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 315         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 316 }
 317
 318 SPACE_INFO_ATTR(flags);
 319 SPACE_INFO_ATTR(total_bytes);
 320 SPACE_INFO_ATTR(bytes_used);
 321 SPACE_INFO_ATTR(bytes_pinned);
 322 SPACE_INFO_ATTR(bytes_reserved);
 323 SPACE_INFO_ATTR(bytes_may_use);
 324 SPACE_INFO_ATTR(disk_used);
 325 SPACE_INFO_ATTR(disk_total);
 326 BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
 327
 328 static struct attribute *space_info_attrs[] = {
 329         BTRFS_ATTR_PTR(flags),
 330         BTRFS_ATTR_PTR(total_bytes),
 331         BTRFS_ATTR_PTR(bytes_used),
 332         BTRFS_ATTR_PTR(bytes_pinned),
 333         BTRFS_ATTR_PTR(bytes_reserved),
 334         BTRFS_ATTR_PTR(bytes_may_use),
 335         BTRFS_ATTR_PTR(disk_used),
 336         BTRFS_ATTR_PTR(disk_total),
 337         BTRFS_ATTR_PTR(total_bytes_pinned),
 338         NULL,
 339 };
 340
 341 static void space_info_release(struct kobject *kobj)
 342 {
 343         struct btrfs_space_info *sinfo = to_space_info(kobj);
 344         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 345         kfree(sinfo);
 346 }
 347
 348 struct kobj_type space_info_ktype = {
 349         .sysfs_ops = &kobj_sysfs_ops,
 350         .release = space_info_release,
 351         .default_attrs = space_info_attrs,
 352 };
 353
 354 static const struct attribute *allocation_attrs[] = {
 355         BTRFS_ATTR_PTR(global_rsv_reserved),
 356         BTRFS_ATTR_PTR(global_rsv_size),
 357         NULL,
 358 };
 359
 360 static ssize_t btrfs_label_show(struct kobject *kobj,
 361                                 struct kobj_attribute *a, char *buf)
 362 {
 363         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 364         return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
 365 }
 366
 367 static ssize_t btrfs_label_store(struct kobject *kobj,
 368                                  struct kobj_attribute *a,
 369                                  const char *buf, size_t len)
 370 {
 371         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 372         struct btrfs_trans_handle *trans;
 373         struct btrfs_root *root = fs_info->fs_root;
 374         int ret;
 375
 376         if (len >= BTRFS_LABEL_SIZE) {
 377                 pr_err("BTRFS: unable to set label with more than %d bytes\n",
 378                        BTRFS_LABEL_SIZE - 1);
 379                 return -EINVAL;
 380         }
 381
 382         trans = btrfs_start_transaction(root, 0);
 383         if (IS_ERR(trans))
 384                 return PTR_ERR(trans);
 385
 386         spin_lock(&root->fs_info->super_lock);
 387         strcpy(fs_info->super_copy->label, buf);
 388         spin_unlock(&root->fs_info->super_lock);
 389         ret = btrfs_commit_transaction(trans, root);
 390
 391         if (!ret)
 392                 return len;
 393
 394         return ret;
 395 }
 396 BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
 397
 398 static struct attribute *btrfs_attrs[] = {
 399         BTRFS_ATTR_PTR(label),
 400         NULL,
 401 };
 402
 403 static void btrfs_release_super_kobj(struct kobject *kobj)
 404 {
 405         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 406         complete(&fs_info->kobj_unregister);
 407 }
 408
 409 static struct kobj_type btrfs_ktype = {
 410         .sysfs_ops      = &kobj_sysfs_ops,
 411         .release        = btrfs_release_super_kobj,
 412         .default_attrs  = btrfs_attrs,
 413 };
 414
 415 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 416 {
 417         if (kobj->ktype != &btrfs_ktype)
 418                 return NULL;
 419         return container_of(kobj, struct btrfs_fs_info, super_kobj);
 420 }
 421
 422 #define NUM_FEATURE_BITS 64
 423 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 424 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 425
 426 static u64 supported_feature_masks[3] = {
 427         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 428         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 429         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 430 };
 431
 432 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 433 {
 434         int set;
 435
 436         for (set = 0; set < FEAT_MAX; set++) {
 437                 int i;
 438                 struct attribute *attrs[2];
 439                 struct attribute_group agroup = {
 440                         .name = "features",
 441                         .attrs = attrs,
 442                 };
 443                 u64 features = get_features(fs_info, set);
 444                 features &= ~supported_feature_masks[set];
 445
 446                 if (!features)
 447                         continue;
 448
 449                 attrs[1] = NULL;
 450                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 451                         struct btrfs_feature_attr *fa;
 452
 453                         if (!(features & (1ULL << i)))
 454                                 continue;
 455
 456                         fa = &btrfs_feature_attrs[set][i];
 457                         attrs[0] = &fa->kobj_attr.attr;
 458                         if (add) {
 459                                 int ret;
 460                                 ret = sysfs_merge_group(&fs_info->super_kobj,
 461                                                         &agroup);
 462                                 if (ret)
 463                                         return ret;
 464                         } else
 465                                 sysfs_unmerge_group(&fs_info->super_kobj,
 466                                                     &agroup);
 467                 }
 468
 469         }
 470         return 0;
 471 }
 472
 473 static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 474 {
 475         kobject_del(&fs_info->super_kobj);
 476         kobject_put(&fs_info->super_kobj);
 477         wait_for_completion(&fs_info->kobj_unregister);
 478 }
 479
 480 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 481 {
 482         if (fs_info->space_info_kobj) {
 483                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 484                 kobject_del(fs_info->space_info_kobj);
 485                 kobject_put(fs_info->space_info_kobj);
 486         }
 487         kobject_del(fs_info->device_dir_kobj);
 488         kobject_put(fs_info->device_dir_kobj);
 489         addrm_unknown_feature_attrs(fs_info, false);
 490         sysfs_remove_group(&fs_info->super_kobj, &btrfs_feature_attr_group);
 491         __btrfs_sysfs_remove_one(fs_info);
 492 }
 493
 494 const char * const btrfs_feature_set_names[3] = {
 495         [FEAT_COMPAT]    = "compat",
 496         [FEAT_COMPAT_RO] = "compat_ro",
 497         [FEAT_INCOMPAT]  = "incompat",
 498 };
 499
 500 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 501 {
 502         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 503         int len = 0;
 504         int i;
 505         char *str;
 506
 507         str = kmalloc(bufsize, GFP_KERNEL);
 508         if (!str)
 509                 return str;
 510
 511         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 512                 const char *name;
 513
 514                 if (!(flags & (1ULL << i)))
 515                         continue;
 516
 517                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 518                 len += snprintf(str + len, bufsize - len, "%s%s",
 519                                 len ? "," : "", name);
 520         }
 521
 522         return str;
 523 }
 524
 525 static void init_feature_attrs(void)
 526 {
 527         struct btrfs_feature_attr *fa;
 528         int set, i;
 529
 530         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 531                      ARRAY_SIZE(btrfs_feature_attrs));
 532         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 533                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 534
 535         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 536         memset(btrfs_unknown_feature_names, 0,
 537                sizeof(btrfs_unknown_feature_names));
 538
 539         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 540                 struct btrfs_feature_attr *sfa;
 541                 struct attribute *a = btrfs_supported_feature_attrs[i];
 542                 int bit;
 543                 sfa = attr_to_btrfs_feature_attr(a);
 544                 bit = ilog2(sfa->feature_bit);
 545                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 546
 547                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 548         }
 549
 550         for (set = 0; set < FEAT_MAX; set++) {
 551                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 552                         char *name = btrfs_unknown_feature_names[set][i];
 553                         fa = &btrfs_feature_attrs[set][i];
 554
 555                         if (fa->kobj_attr.attr.name)
 556                                 continue;
 557
 558                         snprintf(name, 13, "%s:%u",
 559                                  btrfs_feature_set_names[set], i);
 560
 561                         fa->kobj_attr.attr.name = name;
 562                         fa->kobj_attr.attr.mode = S_IRUGO;
 563                         fa->feature_set = set;
 564                         fa->feature_bit = 1ULL << i;
 565                 }
 566         }
 567 }
 568
 569 static int add_device_membership(struct btrfs_fs_info *fs_info)
 570 {
 571         int error = 0;
 572         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 573         struct btrfs_device *dev;
 574
 575         fs_info->device_dir_kobj = kobject_create_and_add("devices",
 576                                                 &fs_info->super_kobj);
 577         if (!fs_info->device_dir_kobj)
 578                 return -ENOMEM;
 579
 580         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 581                 struct hd_struct *disk;
 582                 struct kobject *disk_kobj;
 583
 584                 if (!dev->bdev)
 585                         continue;
 586
 587                 disk = dev->bdev->bd_part;
 588                 disk_kobj = &part_to_dev(disk)->kobj;
 589
 590                 error = sysfs_create_link(fs_info->device_dir_kobj,
 591                                           disk_kobj, disk_kobj->name);
 592                 if (error)
 593                         break;
 594         }
 595
 596         return error;
 597 }
 598
 599 /* /sys/fs/btrfs/ entry */
 600 static struct kset *btrfs_kset;
 601
 602 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 603 {
 604         int error;
 605
 606         init_completion(&fs_info->kobj_unregister);
 607         fs_info->super_kobj.kset = btrfs_kset;
 608         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 609                                      "%pU", fs_info->fsid);
 610         if (error)
 611                 return error;
 612
 613         error = sysfs_create_group(&fs_info->super_kobj,
 614                                    &btrfs_feature_attr_group);
 615         if (error) {
 616                 __btrfs_sysfs_remove_one(fs_info);
 617                 return error;
 618         }
 619
 620         error = addrm_unknown_feature_attrs(fs_info, true);
 621         if (error)
 622                 goto failure;
 623
 624         error = add_device_membership(fs_info);
 625         if (error)
 626                 goto failure;
 627
 628         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 629                                                   &fs_info->super_kobj);
 630         if (!fs_info->space_info_kobj) {
 631                 error = -ENOMEM;
 632                 goto failure;
 633         }
 634
 635         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 636         if (error)
 637                 goto failure;
 638
 639         return 0;
 640 failure:
 641         btrfs_sysfs_remove_one(fs_info);
 642         return error;
 643 }
 644
 645 int btrfs_init_sysfs(void)
 646 {
 647         int ret;
 648         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 649         if (!btrfs_kset)
 650                 return -ENOMEM;
 651
 652         init_feature_attrs();
 653
 654         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 655         if (ret) {
 656                 kset_unregister(btrfs_kset);
 657                 return ret;
 658         }
 659
 660         return 0;
 661 }
 662
 663 void btrfs_exit_sysfs(void)
 664 {
 665         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 666         kset_unregister(btrfs_kset);
 667 }
 668