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(compress_lzov2, COMPRESS_LZOv2);
 202 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 203 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 204 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 205 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 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(compress_lzov2),
 213         BTRFS_FEAT_ATTR_PTR(big_metadata),
 214         BTRFS_FEAT_ATTR_PTR(extended_iref),
 215         BTRFS_FEAT_ATTR_PTR(raid56),
 216         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 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 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 423 {
 424         sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 425         kobject_del(fs_info->device_dir_kobj);
 426         kobject_put(fs_info->device_dir_kobj);
 427         kobject_del(fs_info->space_info_kobj);
 428         kobject_put(fs_info->space_info_kobj);
 429         kobject_del(&fs_info->super_kobj);
 430         kobject_put(&fs_info->super_kobj);
 431         wait_for_completion(&fs_info->kobj_unregister);
 432 }
 433
 434 const char * const btrfs_feature_set_names[3] = {
 435         [FEAT_COMPAT]    = "compat",
 436         [FEAT_COMPAT_RO] = "compat_ro",
 437         [FEAT_INCOMPAT]  = "incompat",
 438 };
 439
 440 #define NUM_FEATURE_BITS 64
 441 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 442 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 443
 444 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 445 {
 446         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 447         int len = 0;
 448         int i;
 449         char *str;
 450
 451         str = kmalloc(bufsize, GFP_KERNEL);
 452         if (!str)
 453                 return str;
 454
 455         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 456                 const char *name;
 457
 458                 if (!(flags & (1ULL << i)))
 459                         continue;
 460
 461                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 462                 len += snprintf(str + len, bufsize - len, "%s%s",
 463                                 len ? "," : "", name);
 464         }
 465
 466         return str;
 467 }
 468
 469 static void init_feature_attrs(void)
 470 {
 471         struct btrfs_feature_attr *fa;
 472         int set, i;
 473
 474         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 475                      ARRAY_SIZE(btrfs_feature_attrs));
 476         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 477                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 478
 479         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 480         memset(btrfs_unknown_feature_names, 0,
 481                sizeof(btrfs_unknown_feature_names));
 482
 483         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 484                 struct btrfs_feature_attr *sfa;
 485                 struct attribute *a = btrfs_supported_feature_attrs[i];
 486                 int bit;
 487                 sfa = attr_to_btrfs_feature_attr(a);
 488                 bit = ilog2(sfa->feature_bit);
 489                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 490
 491                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 492         }
 493
 494         for (set = 0; set < FEAT_MAX; set++) {
 495                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 496                         char *name = btrfs_unknown_feature_names[set][i];
 497                         fa = &btrfs_feature_attrs[set][i];
 498
 499                         if (fa->kobj_attr.attr.name)
 500                                 continue;
 501
 502                         snprintf(name, 13, "%s:%u",
 503                                  btrfs_feature_set_names[set], i);
 504
 505                         fa->kobj_attr.attr.name = name;
 506                         fa->kobj_attr.attr.mode = S_IRUGO;
 507                         fa->feature_set = set;
 508                         fa->feature_bit = 1ULL << i;
 509                 }
 510         }
 511 }
 512
 513 static u64 supported_feature_masks[3] = {
 514         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 515         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 516         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 517 };
 518
 519 static int add_unknown_feature_attrs(struct btrfs_fs_info *fs_info)
 520 {
 521         int set;
 522
 523         for (set = 0; set < FEAT_MAX; set++) {
 524                 int i, count, ret, index = 0;
 525                 struct attribute **attrs;
 526                 struct attribute_group agroup = {
 527                         .name = "features",
 528                 };
 529                 u64 features = get_features(fs_info, set);
 530                 features &= ~supported_feature_masks[set];
 531
 532                 count = hweight64(features);
 533
 534                 if (!count)
 535                         continue;
 536
 537                 attrs = kcalloc(count + 1, sizeof(void *), GFP_KERNEL);
 538
 539                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 540                         struct btrfs_feature_attr *fa;
 541
 542                         if (!(features & (1ULL << i)))
 543                                 continue;
 544
 545                         fa = &btrfs_feature_attrs[set][i];
 546                         attrs[index++] = &fa->kobj_attr.attr;
 547                 }
 548
 549                 attrs[index] = NULL;
 550                 agroup.attrs = attrs;
 551
 552                 ret = sysfs_merge_group(&fs_info->super_kobj, &agroup);
 553                 kfree(attrs);
 554                 if (ret)
 555                         return ret;
 556         }
 557         return 0;
 558 }
 559
 560 static int add_device_membership(struct btrfs_fs_info *fs_info)
 561 {
 562         int error = 0;
 563         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 564         struct btrfs_device *dev;
 565
 566         fs_info->device_dir_kobj = kobject_create_and_add("devices",
 567                                                 &fs_info->super_kobj);
 568         if (!fs_info->device_dir_kobj)
 569                 return -ENOMEM;
 570
 571         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 572                 struct hd_struct *disk = dev->bdev->bd_part;
 573                 struct kobject *disk_kobj = &part_to_dev(disk)->kobj;
 574
 575                 error = sysfs_create_link(fs_info->device_dir_kobj,
 576                                           disk_kobj, disk_kobj->name);
 577                 if (error)
 578                         break;
 579         }
 580
 581         return error;
 582 }
 583
 584 /* /sys/fs/btrfs/ entry */
 585 static struct kset *btrfs_kset;
 586
 587 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 588 {
 589         int error;
 590
 591         init_completion(&fs_info->kobj_unregister);
 592         fs_info->super_kobj.kset = btrfs_kset;
 593         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 594                                      "%pU", fs_info->fsid);
 595
 596         error = sysfs_create_group(&fs_info->super_kobj,
 597                                    &btrfs_feature_attr_group);
 598         if (error)
 599                 goto failure;
 600
 601         error = add_unknown_feature_attrs(fs_info);
 602         if (error)
 603                 goto failure;
 604
 605         error = add_device_membership(fs_info);
 606         if (error)
 607                 goto failure;
 608
 609         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 610                                                   &fs_info->super_kobj);
 611         if (!fs_info->space_info_kobj) {
 612                 error = -ENOMEM;
 613                 goto failure;
 614         }
 615
 616         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 617         if (error)
 618                 goto failure;
 619
 620         return 0;
 621 failure:
 622         btrfs_sysfs_remove_one(fs_info);
 623         return error;
 624 }
 625
 626 int btrfs_init_sysfs(void)
 627 {
 628         int ret;
 629         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 630         if (!btrfs_kset)
 631                 return -ENOMEM;
 632
 633         init_feature_attrs();
 634
 635         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 636         if (ret) {
 637                 kset_unregister(btrfs_kset);
 638                 return ret;
 639         }
 640
 641         return 0;
 642 }
 643
 644 void btrfs_exit_sysfs(void)
 645 {
 646         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 647         kset_unregister(btrfs_kset);
 648 }
 649