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 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 257
 258 static ssize_t raid_bytes_show(struct kobject *kobj,
 259                                struct kobj_attribute *attr, char *buf);
 260 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 261 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 262
 263 static ssize_t raid_bytes_show(struct kobject *kobj,
 264                                struct kobj_attribute *attr, char *buf)
 265
 266 {
 267         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 268         struct btrfs_block_group_cache *block_group;
 269         int index = to_raid_kobj(kobj)->raid_type;
 270         u64 val = 0;
 271
 272         down_read(&sinfo->groups_sem);
 273         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 274                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
 275                         val += block_group->key.offset;
 276                 else
 277                         val += btrfs_block_group_used(&block_group->item);
 278         }
 279         up_read(&sinfo->groups_sem);
 280         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 281 }
 282
 283 static struct attribute *raid_attributes[] = {
 284         BTRFS_RAID_ATTR_PTR(total_bytes),
 285         BTRFS_RAID_ATTR_PTR(used_bytes),
 286         NULL
 287 };
 288
 289 static void release_raid_kobj(struct kobject *kobj)
 290 {
 291         kfree(to_raid_kobj(kobj));
 292 }
 293
 294 struct kobj_type btrfs_raid_ktype = {
 295         .sysfs_ops = &kobj_sysfs_ops,
 296         .release = release_raid_kobj,
 297         .default_attrs = raid_attributes,
 298 };
 299
 300 #define SPACE_INFO_ATTR(field)                                          \
 301 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 302                                              struct kobj_attribute *a,  \
 303                                              char *buf)                 \
 304 {                                                                       \
 305         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 306         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 307 }                                                                       \
 308 BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
 309
 310 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 311                                                        struct kobj_attribute *a,
 312                                                        char *buf)
 313 {
 314         struct btrfs_space_info *sinfo = to_space_info(kobj);
 315         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 316         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 317 }
 318
 319 SPACE_INFO_ATTR(flags);
 320 SPACE_INFO_ATTR(total_bytes);
 321 SPACE_INFO_ATTR(bytes_used);
 322 SPACE_INFO_ATTR(bytes_pinned);
 323 SPACE_INFO_ATTR(bytes_reserved);
 324 SPACE_INFO_ATTR(bytes_may_use);
 325 SPACE_INFO_ATTR(disk_used);
 326 SPACE_INFO_ATTR(disk_total);
 327 BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
 328
 329 static struct attribute *space_info_attrs[] = {
 330         BTRFS_ATTR_PTR(flags),
 331         BTRFS_ATTR_PTR(total_bytes),
 332         BTRFS_ATTR_PTR(bytes_used),
 333         BTRFS_ATTR_PTR(bytes_pinned),
 334         BTRFS_ATTR_PTR(bytes_reserved),
 335         BTRFS_ATTR_PTR(bytes_may_use),
 336         BTRFS_ATTR_PTR(disk_used),
 337         BTRFS_ATTR_PTR(disk_total),
 338         BTRFS_ATTR_PTR(total_bytes_pinned),
 339         NULL,
 340 };
 341
 342 static void space_info_release(struct kobject *kobj)
 343 {
 344         struct btrfs_space_info *sinfo = to_space_info(kobj);
 345         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 346         kfree(sinfo);
 347 }
 348
 349 struct kobj_type space_info_ktype = {
 350         .sysfs_ops = &kobj_sysfs_ops,
 351         .release = space_info_release,
 352         .default_attrs = space_info_attrs,
 353 };
 354
 355 static const struct attribute *allocation_attrs[] = {
 356         BTRFS_ATTR_PTR(global_rsv_reserved),
 357         BTRFS_ATTR_PTR(global_rsv_size),
 358         NULL,
 359 };
 360
 361 static ssize_t btrfs_label_show(struct kobject *kobj,
 362                                 struct kobj_attribute *a, char *buf)
 363 {
 364         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 365         return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
 366 }
 367
 368 static ssize_t btrfs_label_store(struct kobject *kobj,
 369                                  struct kobj_attribute *a,
 370                                  const char *buf, size_t len)
 371 {
 372         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 373         struct btrfs_trans_handle *trans;
 374         struct btrfs_root *root = fs_info->fs_root;
 375         int ret;
 376
 377         if (len >= BTRFS_LABEL_SIZE) {
 378                 pr_err("BTRFS: unable to set label with more than %d bytes\n",
 379                        BTRFS_LABEL_SIZE - 1);
 380                 return -EINVAL;
 381         }
 382
 383         trans = btrfs_start_transaction(root, 0);
 384         if (IS_ERR(trans))
 385                 return PTR_ERR(trans);
 386
 387         spin_lock(&root->fs_info->super_lock);
 388         strcpy(fs_info->super_copy->label, buf);
 389         spin_unlock(&root->fs_info->super_lock);
 390         ret = btrfs_commit_transaction(trans, root);
 391
 392         if (!ret)
 393                 return len;
 394
 395         return ret;
 396 }
 397 BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
 398
 399 static struct attribute *btrfs_attrs[] = {
 400         BTRFS_ATTR_PTR(label),
 401         NULL,
 402 };
 403
 404 static void btrfs_release_super_kobj(struct kobject *kobj)
 405 {
 406         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 407         complete(&fs_info->kobj_unregister);
 408 }
 409
 410 static struct kobj_type btrfs_ktype = {
 411         .sysfs_ops      = &kobj_sysfs_ops,
 412         .release        = btrfs_release_super_kobj,
 413         .default_attrs  = btrfs_attrs,
 414 };
 415
 416 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 417 {
 418         if (kobj->ktype != &btrfs_ktype)
 419                 return NULL;
 420         return container_of(kobj, struct btrfs_fs_info, super_kobj);
 421 }
 422
 423 #define NUM_FEATURE_BITS 64
 424 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 425 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 426
 427 static u64 supported_feature_masks[3] = {
 428         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 429         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 430         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 431 };
 432
 433 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 434 {
 435         int set;
 436
 437         for (set = 0; set < FEAT_MAX; set++) {
 438                 int i;
 439                 struct attribute *attrs[2];
 440                 struct attribute_group agroup = {
 441                         .name = "features",
 442                         .attrs = attrs,
 443                 };
 444                 u64 features = get_features(fs_info, set);
 445                 features &= ~supported_feature_masks[set];
 446
 447                 if (!features)
 448                         continue;
 449
 450                 attrs[1] = NULL;
 451                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 452                         struct btrfs_feature_attr *fa;
 453
 454                         if (!(features & (1ULL << i)))
 455                                 continue;
 456
 457                         fa = &btrfs_feature_attrs[set][i];
 458                         attrs[0] = &fa->kobj_attr.attr;
 459                         if (add) {
 460                                 int ret;
 461                                 ret = sysfs_merge_group(&fs_info->super_kobj,
 462                                                         &agroup);
 463                                 if (ret)
 464                                         return ret;
 465                         } else
 466                                 sysfs_unmerge_group(&fs_info->super_kobj,
 467                                                     &agroup);
 468                 }
 469
 470         }
 471         return 0;
 472 }
 473
 474 static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 475 {
 476         kobject_del(&fs_info->super_kobj);
 477         kobject_put(&fs_info->super_kobj);
 478         wait_for_completion(&fs_info->kobj_unregister);
 479 }
 480
 481 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 482 {
 483         if (fs_info->space_info_kobj) {
 484                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 485                 kobject_del(fs_info->space_info_kobj);
 486                 kobject_put(fs_info->space_info_kobj);
 487         }
 488         kobject_del(fs_info->device_dir_kobj);
 489         kobject_put(fs_info->device_dir_kobj);
 490         addrm_unknown_feature_attrs(fs_info, false);
 491         sysfs_remove_group(&fs_info->super_kobj, &btrfs_feature_attr_group);
 492         __btrfs_sysfs_remove_one(fs_info);
 493 }
 494
 495 const char * const btrfs_feature_set_names[3] = {
 496         [FEAT_COMPAT]    = "compat",
 497         [FEAT_COMPAT_RO] = "compat_ro",
 498         [FEAT_INCOMPAT]  = "incompat",
 499 };
 500
 501 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 502 {
 503         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 504         int len = 0;
 505         int i;
 506         char *str;
 507
 508         str = kmalloc(bufsize, GFP_KERNEL);
 509         if (!str)
 510                 return str;
 511
 512         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 513                 const char *name;
 514
 515                 if (!(flags & (1ULL << i)))
 516                         continue;
 517
 518                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 519                 len += snprintf(str + len, bufsize - len, "%s%s",
 520                                 len ? "," : "", name);
 521         }
 522
 523         return str;
 524 }
 525
 526 static void init_feature_attrs(void)
 527 {
 528         struct btrfs_feature_attr *fa;
 529         int set, i;
 530
 531         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 532                      ARRAY_SIZE(btrfs_feature_attrs));
 533         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 534                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 535
 536         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 537         memset(btrfs_unknown_feature_names, 0,
 538                sizeof(btrfs_unknown_feature_names));
 539
 540         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 541                 struct btrfs_feature_attr *sfa;
 542                 struct attribute *a = btrfs_supported_feature_attrs[i];
 543                 int bit;
 544                 sfa = attr_to_btrfs_feature_attr(a);
 545                 bit = ilog2(sfa->feature_bit);
 546                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 547
 548                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 549         }
 550
 551         for (set = 0; set < FEAT_MAX; set++) {
 552                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 553                         char *name = btrfs_unknown_feature_names[set][i];
 554                         fa = &btrfs_feature_attrs[set][i];
 555
 556                         if (fa->kobj_attr.attr.name)
 557                                 continue;
 558
 559                         snprintf(name, 13, "%s:%u",
 560                                  btrfs_feature_set_names[set], i);
 561
 562                         fa->kobj_attr.attr.name = name;
 563                         fa->kobj_attr.attr.mode = S_IRUGO;
 564                         fa->feature_set = set;
 565                         fa->feature_bit = 1ULL << i;
 566                 }
 567         }
 568 }
 569
 570 static int add_device_membership(struct btrfs_fs_info *fs_info)
 571 {
 572         int error = 0;
 573         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 574         struct btrfs_device *dev;
 575
 576         fs_info->device_dir_kobj = kobject_create_and_add("devices",
 577                                                 &fs_info->super_kobj);
 578         if (!fs_info->device_dir_kobj)
 579                 return -ENOMEM;
 580
 581         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 582                 struct hd_struct *disk;
 583                 struct kobject *disk_kobj;
 584
 585                 if (!dev->bdev)
 586                         continue;
 587
 588                 disk = dev->bdev->bd_part;
 589                 disk_kobj = &part_to_dev(disk)->kobj;
 590
 591                 error = sysfs_create_link(fs_info->device_dir_kobj,
 592                                           disk_kobj, disk_kobj->name);
 593                 if (error)
 594                         break;
 595         }
 596
 597         return error;
 598 }
 599
 600 /* /sys/fs/btrfs/ entry */
 601 static struct kset *btrfs_kset;
 602
 603 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 604 {
 605         int error;
 606
 607         init_completion(&fs_info->kobj_unregister);
 608         fs_info->super_kobj.kset = btrfs_kset;
 609         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 610                                      "%pU", fs_info->fsid);
 611         if (error)
 612                 return error;
 613
 614         error = sysfs_create_group(&fs_info->super_kobj,
 615                                    &btrfs_feature_attr_group);
 616         if (error) {
 617                 __btrfs_sysfs_remove_one(fs_info);
 618                 return error;
 619         }
 620
 621         error = addrm_unknown_feature_attrs(fs_info, true);
 622         if (error)
 623                 goto failure;
 624
 625         error = add_device_membership(fs_info);
 626         if (error)
 627                 goto failure;
 628
 629         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 630                                                   &fs_info->super_kobj);
 631         if (!fs_info->space_info_kobj) {
 632                 error = -ENOMEM;
 633                 goto failure;
 634         }
 635
 636         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 637         if (error)
 638                 goto failure;
 639
 640         return 0;
 641 failure:
 642         btrfs_sysfs_remove_one(fs_info);
 643         return error;
 644 }
 645
 646 int btrfs_init_sysfs(void)
 647 {
 648         int ret;
 649         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 650         if (!btrfs_kset)
 651                 return -ENOMEM;
 652
 653         init_feature_attrs();
 654
 655         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 656         if (ret) {
 657                 kset_unregister(btrfs_kset);
 658                 return ret;
 659         }
 660
 661         return 0;
 662 }
 663
 664 void btrfs_exit_sysfs(void)
 665 {
 666         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 667         kset_unregister(btrfs_kset);
 668 }
 669