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
 206 static struct attribute *btrfs_supported_feature_attrs[] = {
 207         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 208         BTRFS_FEAT_ATTR_PTR(default_subvol),
 209         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 210         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 211         BTRFS_FEAT_ATTR_PTR(big_metadata),
 212         BTRFS_FEAT_ATTR_PTR(extended_iref),
 213         BTRFS_FEAT_ATTR_PTR(raid56),
 214         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 215         NULL
 216 };
 217
 218 static const struct attribute_group btrfs_feature_attr_group = {
 219         .name = "features",
 220         .is_visible = btrfs_feature_visible,
 221         .attrs = btrfs_supported_feature_attrs,
 222 };
 223
 224 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 225 {
 226         u64 val;
 227         if (lock)
 228                 spin_lock(lock);
 229         val = *value_ptr;
 230         if (lock)
 231                 spin_unlock(lock);
 232         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 233 }
 234
 235 static ssize_t global_rsv_size_show(struct kobject *kobj,
 236                                     struct kobj_attribute *ka, char *buf)
 237 {
 238         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 239         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 240         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 241 }
 242 BTRFS_ATTR(global_rsv_size, 0444, global_rsv_size_show);
 243
 244 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 245                                         struct kobj_attribute *a, char *buf)
 246 {
 247         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 248         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 249         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 250 }
 251 BTRFS_ATTR(global_rsv_reserved, 0444, global_rsv_reserved_show);
 252
 253 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 254
 255 static ssize_t raid_bytes_show(struct kobject *kobj,
 256                                struct kobj_attribute *attr, char *buf);
 257 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 258 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 259
 260 static ssize_t raid_bytes_show(struct kobject *kobj,
 261                                struct kobj_attribute *attr, char *buf)
 262
 263 {
 264         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 265         struct btrfs_block_group_cache *block_group;
 266         int index = kobj - sinfo->block_group_kobjs;
 267         u64 val = 0;
 268
 269         down_read(&sinfo->groups_sem);
 270         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 271                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
 272                         val += block_group->key.offset;
 273                 else
 274                         val += btrfs_block_group_used(&block_group->item);
 275         }
 276         up_read(&sinfo->groups_sem);
 277         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 278 }
 279
 280 static struct attribute *raid_attributes[] = {
 281         BTRFS_RAID_ATTR_PTR(total_bytes),
 282         BTRFS_RAID_ATTR_PTR(used_bytes),
 283         NULL
 284 };
 285
 286 static void release_raid_kobj(struct kobject *kobj)
 287 {
 288         kobject_put(kobj->parent);
 289 }
 290
 291 struct kobj_type btrfs_raid_ktype = {
 292         .sysfs_ops = &kobj_sysfs_ops,
 293         .release = release_raid_kobj,
 294         .default_attrs = raid_attributes,
 295 };
 296
 297 #define SPACE_INFO_ATTR(field)                                          \
 298 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 299                                              struct kobj_attribute *a,  \
 300                                              char *buf)                 \
 301 {                                                                       \
 302         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 303         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 304 }                                                                       \
 305 BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
 306
 307 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 308                                                        struct kobj_attribute *a,
 309                                                        char *buf)
 310 {
 311         struct btrfs_space_info *sinfo = to_space_info(kobj);
 312         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 313         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 314 }
 315
 316 SPACE_INFO_ATTR(flags);
 317 SPACE_INFO_ATTR(total_bytes);
 318 SPACE_INFO_ATTR(bytes_used);
 319 SPACE_INFO_ATTR(bytes_pinned);
 320 SPACE_INFO_ATTR(bytes_reserved);
 321 SPACE_INFO_ATTR(bytes_may_use);
 322 SPACE_INFO_ATTR(disk_used);
 323 SPACE_INFO_ATTR(disk_total);
 324 BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
 325
 326 static struct attribute *space_info_attrs[] = {
 327         BTRFS_ATTR_PTR(flags),
 328         BTRFS_ATTR_PTR(total_bytes),
 329         BTRFS_ATTR_PTR(bytes_used),
 330         BTRFS_ATTR_PTR(bytes_pinned),
 331         BTRFS_ATTR_PTR(bytes_reserved),
 332         BTRFS_ATTR_PTR(bytes_may_use),
 333         BTRFS_ATTR_PTR(disk_used),
 334         BTRFS_ATTR_PTR(disk_total),
 335         BTRFS_ATTR_PTR(total_bytes_pinned),
 336         NULL,
 337 };
 338
 339 static void space_info_release(struct kobject *kobj)
 340 {
 341         struct btrfs_space_info *sinfo = to_space_info(kobj);
 342         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 343         kfree(sinfo);
 344 }
 345
 346 struct kobj_type space_info_ktype = {
 347         .sysfs_ops = &kobj_sysfs_ops,
 348         .release = space_info_release,
 349         .default_attrs = space_info_attrs,
 350 };
 351
 352 static const struct attribute *allocation_attrs[] = {
 353         BTRFS_ATTR_PTR(global_rsv_reserved),
 354         BTRFS_ATTR_PTR(global_rsv_size),
 355         NULL,
 356 };
 357
 358 static ssize_t btrfs_label_show(struct kobject *kobj,
 359                                 struct kobj_attribute *a, char *buf)
 360 {
 361         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 362         return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
 363 }
 364
 365 static ssize_t btrfs_label_store(struct kobject *kobj,
 366                                  struct kobj_attribute *a,
 367                                  const char *buf, size_t len)
 368 {
 369         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 370         struct btrfs_trans_handle *trans;
 371         struct btrfs_root *root = fs_info->fs_root;
 372         int ret;
 373
 374         if (len >= BTRFS_LABEL_SIZE) {
 375                 pr_err("BTRFS: unable to set label with more than %d bytes\n",
 376                        BTRFS_LABEL_SIZE - 1);
 377                 return -EINVAL;
 378         }
 379
 380         trans = btrfs_start_transaction(root, 0);
 381         if (IS_ERR(trans))
 382                 return PTR_ERR(trans);
 383
 384         spin_lock(&root->fs_info->super_lock);
 385         strcpy(fs_info->super_copy->label, buf);
 386         spin_unlock(&root->fs_info->super_lock);
 387         ret = btrfs_commit_transaction(trans, root);
 388
 389         if (!ret)
 390                 return len;
 391
 392         return ret;
 393 }
 394 BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
 395
 396 static struct attribute *btrfs_attrs[] = {
 397         BTRFS_ATTR_PTR(label),
 398         NULL,
 399 };
 400
 401 static void btrfs_release_super_kobj(struct kobject *kobj)
 402 {
 403         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 404         complete(&fs_info->kobj_unregister);
 405 }
 406
 407 static struct kobj_type btrfs_ktype = {
 408         .sysfs_ops      = &kobj_sysfs_ops,
 409         .release        = btrfs_release_super_kobj,
 410         .default_attrs  = btrfs_attrs,
 411 };
 412
 413 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 414 {
 415         if (kobj->ktype != &btrfs_ktype)
 416                 return NULL;
 417         return container_of(kobj, struct btrfs_fs_info, super_kobj);
 418 }
 419
 420 #define NUM_FEATURE_BITS 64
 421 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 422 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 423
 424 static u64 supported_feature_masks[3] = {
 425         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 426         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 427         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 428 };
 429
 430 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 431 {
 432         int set;
 433
 434         for (set = 0; set < FEAT_MAX; set++) {
 435                 int i;
 436                 struct attribute *attrs[2];
 437                 struct attribute_group agroup = {
 438                         .name = "features",
 439                         .attrs = attrs,
 440                 };
 441                 u64 features = get_features(fs_info, set);
 442                 features &= ~supported_feature_masks[set];
 443
 444                 if (!features)
 445                         continue;
 446
 447                 attrs[1] = NULL;
 448                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 449                         struct btrfs_feature_attr *fa;
 450
 451                         if (!(features & (1ULL << i)))
 452                                 continue;
 453
 454                         fa = &btrfs_feature_attrs[set][i];
 455                         attrs[0] = &fa->kobj_attr.attr;
 456                         if (add) {
 457                                 int ret;
 458                                 ret = sysfs_merge_group(&fs_info->super_kobj,
 459                                                         &agroup);
 460                                 if (ret)
 461                                         return ret;
 462                         } else
 463                                 sysfs_unmerge_group(&fs_info->super_kobj,
 464                                                     &agroup);
 465                 }
 466
 467         }
 468         return 0;
 469 }
 470
 471 static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 472 {
 473         kobject_del(&fs_info->super_kobj);
 474         kobject_put(&fs_info->super_kobj);
 475         wait_for_completion(&fs_info->kobj_unregister);
 476 }
 477
 478 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 479 {
 480         if (fs_info->space_info_kobj) {
 481                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 482                 kobject_del(fs_info->space_info_kobj);
 483                 kobject_put(fs_info->space_info_kobj);
 484         }
 485         kobject_del(fs_info->device_dir_kobj);
 486         kobject_put(fs_info->device_dir_kobj);
 487         addrm_unknown_feature_attrs(fs_info, false);
 488         sysfs_remove_group(&fs_info->super_kobj, &btrfs_feature_attr_group);
 489         __btrfs_sysfs_remove_one(fs_info);
 490 }
 491
 492 const char * const btrfs_feature_set_names[3] = {
 493         [FEAT_COMPAT]    = "compat",
 494         [FEAT_COMPAT_RO] = "compat_ro",
 495         [FEAT_INCOMPAT]  = "incompat",
 496 };
 497
 498 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 499 {
 500         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 501         int len = 0;
 502         int i;
 503         char *str;
 504
 505         str = kmalloc(bufsize, GFP_KERNEL);
 506         if (!str)
 507                 return str;
 508
 509         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 510                 const char *name;
 511
 512                 if (!(flags & (1ULL << i)))
 513                         continue;
 514
 515                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 516                 len += snprintf(str + len, bufsize - len, "%s%s",
 517                                 len ? "," : "", name);
 518         }
 519
 520         return str;
 521 }
 522
 523 static void init_feature_attrs(void)
 524 {
 525         struct btrfs_feature_attr *fa;
 526         int set, i;
 527
 528         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 529                      ARRAY_SIZE(btrfs_feature_attrs));
 530         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 531                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 532
 533         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 534         memset(btrfs_unknown_feature_names, 0,
 535                sizeof(btrfs_unknown_feature_names));
 536
 537         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 538                 struct btrfs_feature_attr *sfa;
 539                 struct attribute *a = btrfs_supported_feature_attrs[i];
 540                 int bit;
 541                 sfa = attr_to_btrfs_feature_attr(a);
 542                 bit = ilog2(sfa->feature_bit);
 543                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 544
 545                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 546         }
 547
 548         for (set = 0; set < FEAT_MAX; set++) {
 549                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 550                         char *name = btrfs_unknown_feature_names[set][i];
 551                         fa = &btrfs_feature_attrs[set][i];
 552
 553                         if (fa->kobj_attr.attr.name)
 554                                 continue;
 555
 556                         snprintf(name, 13, "%s:%u",
 557                                  btrfs_feature_set_names[set], i);
 558
 559                         fa->kobj_attr.attr.name = name;
 560                         fa->kobj_attr.attr.mode = S_IRUGO;
 561                         fa->feature_set = set;
 562                         fa->feature_bit = 1ULL << i;
 563                 }
 564         }
 565 }
 566
 567 static int add_device_membership(struct btrfs_fs_info *fs_info)
 568 {
 569         int error = 0;
 570         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 571         struct btrfs_device *dev;
 572
 573         fs_info->device_dir_kobj = kobject_create_and_add("devices",
 574                                                 &fs_info->super_kobj);
 575         if (!fs_info->device_dir_kobj)
 576                 return -ENOMEM;
 577
 578         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 579                 struct hd_struct *disk = dev->bdev->bd_part;
 580                 struct kobject *disk_kobj = &part_to_dev(disk)->kobj;
 581
 582                 error = sysfs_create_link(fs_info->device_dir_kobj,
 583                                           disk_kobj, disk_kobj->name);
 584                 if (error)
 585                         break;
 586         }
 587
 588         return error;
 589 }
 590
 591 /* /sys/fs/btrfs/ entry */
 592 static struct kset *btrfs_kset;
 593
 594 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 595 {
 596         int error;
 597
 598         init_completion(&fs_info->kobj_unregister);
 599         fs_info->super_kobj.kset = btrfs_kset;
 600         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 601                                      "%pU", fs_info->fsid);
 602         if (error)
 603                 return error;
 604
 605         error = sysfs_create_group(&fs_info->super_kobj,
 606                                    &btrfs_feature_attr_group);
 607         if (error) {
 608                 __btrfs_sysfs_remove_one(fs_info);
 609                 return error;
 610         }
 611
 612         error = addrm_unknown_feature_attrs(fs_info, true);
 613         if (error)
 614                 goto failure;
 615
 616         error = add_device_membership(fs_info);
 617         if (error)
 618                 goto failure;
 619
 620         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 621                                                   &fs_info->super_kobj);
 622         if (!fs_info->space_info_kobj) {
 623                 error = -ENOMEM;
 624                 goto failure;
 625         }
 626
 627         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 628         if (error)
 629                 goto failure;
 630
 631         return 0;
 632 failure:
 633         btrfs_sysfs_remove_one(fs_info);
 634         return error;
 635 }
 636
 637 int btrfs_init_sysfs(void)
 638 {
 639         int ret;
 640         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 641         if (!btrfs_kset)
 642                 return -ENOMEM;
 643
 644         init_feature_attrs();
 645
 646         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 647         if (ret) {
 648                 kset_unregister(btrfs_kset);
 649                 return ret;
 650         }
 651
 652         return 0;
 653 }
 654
 655 void btrfs_exit_sysfs(void)
 656 {
 657         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 658         kset_unregister(btrfs_kset);
 659 }
 660