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 #include <linux/debugfs.h>
  28
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "transaction.h"
  32 #include "sysfs.h"
  33 #include "volumes.h"
  34
  35 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  36
  37 static u64 get_features(struct btrfs_fs_info *fs_info,
  38                         enum btrfs_feature_set set)
  39 {
  40         struct btrfs_super_block *disk_super = fs_info->super_copy;
  41         if (set == FEAT_COMPAT)
  42                 return btrfs_super_compat_flags(disk_super);
  43         else if (set == FEAT_COMPAT_RO)
  44                 return btrfs_super_compat_ro_flags(disk_super);
  45         else
  46                 return btrfs_super_incompat_flags(disk_super);
  47 }
  48
  49 static void set_features(struct btrfs_fs_info *fs_info,
  50                          enum btrfs_feature_set set, u64 features)
  51 {
  52         struct btrfs_super_block *disk_super = fs_info->super_copy;
  53         if (set == FEAT_COMPAT)
  54                 btrfs_set_super_compat_flags(disk_super, features);
  55         else if (set == FEAT_COMPAT_RO)
  56                 btrfs_set_super_compat_ro_flags(disk_super, features);
  57         else
  58                 btrfs_set_super_incompat_flags(disk_super, features);
  59 }
  60
  61 static int can_modify_feature(struct btrfs_feature_attr *fa)
  62 {
  63         int val = 0;
  64         u64 set, clear;
  65         switch (fa->feature_set) {
  66         case FEAT_COMPAT:
  67                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  68                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  69                 break;
  70         case FEAT_COMPAT_RO:
  71                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  72                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  73                 break;
  74         case FEAT_INCOMPAT:
  75                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  76                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  77                 break;
  78         default:
  79                 printk(KERN_WARNING "btrfs: sysfs: unknown feature set %d\n",
  80                                 fa->feature_set);
  81                 return 0;
  82         }
  83
  84         if (set & fa->feature_bit)
  85                 val |= 1;
  86         if (clear & fa->feature_bit)
  87                 val |= 2;
  88
  89         return val;
  90 }
  91
  92 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  93                                        struct kobj_attribute *a, char *buf)
  94 {
  95         int val = 0;
  96         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  97         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  98         if (fs_info) {
  99                 u64 features = get_features(fs_info, fa->feature_set);
 100                 if (features & fa->feature_bit)
 101                         val = 1;
 102         } else
 103                 val = can_modify_feature(fa);
 104
 105         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 106 }
 107
 108 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 109                                         struct kobj_attribute *a,
 110                                         const char *buf, size_t count)
 111 {
 112         struct btrfs_fs_info *fs_info;
 113         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 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         spin_lock(&fs_info->super_lock);
 156         features = get_features(fs_info, fa->feature_set);
 157         if (val)
 158                 features |= fa->feature_bit;
 159         else
 160                 features &= ~fa->feature_bit;
 161         set_features(fs_info, fa->feature_set, features);
 162         spin_unlock(&fs_info->super_lock);
 163
 164         /*
 165          * We don't want to do full transaction commit from inside sysfs
 166          */
 167         btrfs_set_pending(fs_info, COMMIT);
 168         wake_up_process(fs_info->transaction_kthread);
 169
 170         return count;
 171 }
 172
 173 static umode_t btrfs_feature_visible(struct kobject *kobj,
 174                                      struct attribute *attr, int unused)
 175 {
 176         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 177         umode_t mode = attr->mode;
 178
 179         if (fs_info) {
 180                 struct btrfs_feature_attr *fa;
 181                 u64 features;
 182
 183                 fa = attr_to_btrfs_feature_attr(attr);
 184                 features = get_features(fs_info, fa->feature_set);
 185
 186                 if (can_modify_feature(fa))
 187                         mode |= S_IWUSR;
 188                 else if (!(features & fa->feature_bit))
 189                         mode = 0;
 190         }
 191
 192         return mode;
 193 }
 194
 195 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 196 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 197 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 198 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 199 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 200 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 201 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 202 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 203 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 204
 205 static struct attribute *btrfs_supported_feature_attrs[] = {
 206         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 207         BTRFS_FEAT_ATTR_PTR(default_subvol),
 208         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 209         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 210         BTRFS_FEAT_ATTR_PTR(big_metadata),
 211         BTRFS_FEAT_ATTR_PTR(extended_iref),
 212         BTRFS_FEAT_ATTR_PTR(raid56),
 213         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 214         BTRFS_FEAT_ATTR_PTR(no_holes),
 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, 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, global_rsv_reserved_show);
 252
 253 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 254 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 255
 256 static ssize_t raid_bytes_show(struct kobject *kobj,
 257                                struct kobj_attribute *attr, char *buf);
 258 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 259 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 260
 261 static ssize_t raid_bytes_show(struct kobject *kobj,
 262                                struct kobj_attribute *attr, char *buf)
 263
 264 {
 265         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 266         struct btrfs_block_group_cache *block_group;
 267         int index = to_raid_kobj(kobj)->raid_type;
 268         u64 val = 0;
 269
 270         down_read(&sinfo->groups_sem);
 271         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 272                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
 273                         val += block_group->key.offset;
 274                 else
 275                         val += btrfs_block_group_used(&block_group->item);
 276         }
 277         up_read(&sinfo->groups_sem);
 278         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 279 }
 280
 281 static struct attribute *raid_attributes[] = {
 282         BTRFS_RAID_ATTR_PTR(total_bytes),
 283         BTRFS_RAID_ATTR_PTR(used_bytes),
 284         NULL
 285 };
 286
 287 static void release_raid_kobj(struct kobject *kobj)
 288 {
 289         kfree(to_raid_kobj(kobj));
 290 }
 291
 292 struct kobj_type btrfs_raid_ktype = {
 293         .sysfs_ops = &kobj_sysfs_ops,
 294         .release = release_raid_kobj,
 295         .default_attrs = raid_attributes,
 296 };
 297
 298 #define SPACE_INFO_ATTR(field)                                          \
 299 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 300                                              struct kobj_attribute *a,  \
 301                                              char *buf)                 \
 302 {                                                                       \
 303         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 304         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 305 }                                                                       \
 306 BTRFS_ATTR(field, btrfs_space_info_show_##field)
 307
 308 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 309                                                        struct kobj_attribute *a,
 310                                                        char *buf)
 311 {
 312         struct btrfs_space_info *sinfo = to_space_info(kobj);
 313         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 314         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 315 }
 316
 317 SPACE_INFO_ATTR(flags);
 318 SPACE_INFO_ATTR(total_bytes);
 319 SPACE_INFO_ATTR(bytes_used);
 320 SPACE_INFO_ATTR(bytes_pinned);
 321 SPACE_INFO_ATTR(bytes_reserved);
 322 SPACE_INFO_ATTR(bytes_may_use);
 323 SPACE_INFO_ATTR(disk_used);
 324 SPACE_INFO_ATTR(disk_total);
 325 BTRFS_ATTR(total_bytes_pinned, btrfs_space_info_show_total_bytes_pinned);
 326
 327 static struct attribute *space_info_attrs[] = {
 328         BTRFS_ATTR_PTR(flags),
 329         BTRFS_ATTR_PTR(total_bytes),
 330         BTRFS_ATTR_PTR(bytes_used),
 331         BTRFS_ATTR_PTR(bytes_pinned),
 332         BTRFS_ATTR_PTR(bytes_reserved),
 333         BTRFS_ATTR_PTR(bytes_may_use),
 334         BTRFS_ATTR_PTR(disk_used),
 335         BTRFS_ATTR_PTR(disk_total),
 336         BTRFS_ATTR_PTR(total_bytes_pinned),
 337         NULL,
 338 };
 339
 340 static void space_info_release(struct kobject *kobj)
 341 {
 342         struct btrfs_space_info *sinfo = to_space_info(kobj);
 343         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 344         kfree(sinfo);
 345 }
 346
 347 struct kobj_type space_info_ktype = {
 348         .sysfs_ops = &kobj_sysfs_ops,
 349         .release = space_info_release,
 350         .default_attrs = space_info_attrs,
 351 };
 352
 353 static const struct attribute *allocation_attrs[] = {
 354         BTRFS_ATTR_PTR(global_rsv_reserved),
 355         BTRFS_ATTR_PTR(global_rsv_size),
 356         NULL,
 357 };
 358
 359 static ssize_t btrfs_label_show(struct kobject *kobj,
 360                                 struct kobj_attribute *a, char *buf)
 361 {
 362         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 363         char *label = fs_info->super_copy->label;
 364         return snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", 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         size_t p_len;
 373
 374         if (fs_info->sb->s_flags & MS_RDONLY)
 375                 return -EROFS;
 376
 377         /*
 378          * p_len is the len until the first occurrence of either
 379          * '\n' or '\0'
 380          */
 381         p_len = strcspn(buf, "\n");
 382
 383         if (p_len >= BTRFS_LABEL_SIZE)
 384                 return -EINVAL;
 385
 386         spin_lock(&fs_info->super_lock);
 387         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 388         memcpy(fs_info->super_copy->label, buf, p_len);
 389         spin_unlock(&fs_info->super_lock);
 390
 391         /*
 392          * We don't want to do full transaction commit from inside sysfs
 393          */
 394         btrfs_set_pending(fs_info, COMMIT);
 395         wake_up_process(fs_info->transaction_kthread);
 396
 397         return len;
 398 }
 399 BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
 400
 401 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 402                                 struct kobj_attribute *a, char *buf)
 403 {
 404         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 405
 406         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 407 }
 408
 409 BTRFS_ATTR(nodesize, btrfs_nodesize_show);
 410
 411 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 412                                 struct kobj_attribute *a, char *buf)
 413 {
 414         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 415
 416         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 417 }
 418
 419 BTRFS_ATTR(sectorsize, btrfs_sectorsize_show);
 420
 421 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 422                                 struct kobj_attribute *a, char *buf)
 423 {
 424         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 425
 426         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 427 }
 428
 429 BTRFS_ATTR(clone_alignment, btrfs_clone_alignment_show);
 430
 431 static struct attribute *btrfs_attrs[] = {
 432         BTRFS_ATTR_PTR(label),
 433         BTRFS_ATTR_PTR(nodesize),
 434         BTRFS_ATTR_PTR(sectorsize),
 435         BTRFS_ATTR_PTR(clone_alignment),
 436         NULL,
 437 };
 438
 439 static void btrfs_release_super_kobj(struct kobject *kobj)
 440 {
 441         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 442         complete(&fs_info->kobj_unregister);
 443 }
 444
 445 static struct kobj_type btrfs_ktype = {
 446         .sysfs_ops      = &kobj_sysfs_ops,
 447         .release        = btrfs_release_super_kobj,
 448         .default_attrs  = btrfs_attrs,
 449 };
 450
 451 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 452 {
 453         if (kobj->ktype != &btrfs_ktype)
 454                 return NULL;
 455         return container_of(kobj, struct btrfs_fs_info, super_kobj);
 456 }
 457
 458 #define NUM_FEATURE_BITS 64
 459 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 460 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 461
 462 static u64 supported_feature_masks[3] = {
 463         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 464         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 465         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 466 };
 467
 468 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 469 {
 470         int set;
 471
 472         for (set = 0; set < FEAT_MAX; set++) {
 473                 int i;
 474                 struct attribute *attrs[2];
 475                 struct attribute_group agroup = {
 476                         .name = "features",
 477                         .attrs = attrs,
 478                 };
 479                 u64 features = get_features(fs_info, set);
 480                 features &= ~supported_feature_masks[set];
 481
 482                 if (!features)
 483                         continue;
 484
 485                 attrs[1] = NULL;
 486                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 487                         struct btrfs_feature_attr *fa;
 488
 489                         if (!(features & (1ULL << i)))
 490                                 continue;
 491
 492                         fa = &btrfs_feature_attrs[set][i];
 493                         attrs[0] = &fa->kobj_attr.attr;
 494                         if (add) {
 495                                 int ret;
 496                                 ret = sysfs_merge_group(&fs_info->super_kobj,
 497                                                         &agroup);
 498                                 if (ret)
 499                                         return ret;
 500                         } else
 501                                 sysfs_unmerge_group(&fs_info->super_kobj,
 502                                                     &agroup);
 503                 }
 504
 505         }
 506         return 0;
 507 }
 508
 509 static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 510 {
 511         kobject_del(&fs_info->super_kobj);
 512         kobject_put(&fs_info->super_kobj);
 513         wait_for_completion(&fs_info->kobj_unregister);
 514 }
 515
 516 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 517 {
 518         if (fs_info->space_info_kobj) {
 519                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 520                 kobject_del(fs_info->space_info_kobj);
 521                 kobject_put(fs_info->space_info_kobj);
 522         }
 523         kobject_del(fs_info->device_dir_kobj);
 524         kobject_put(fs_info->device_dir_kobj);
 525         addrm_unknown_feature_attrs(fs_info, false);
 526         sysfs_remove_group(&fs_info->super_kobj, &btrfs_feature_attr_group);
 527         __btrfs_sysfs_remove_one(fs_info);
 528 }
 529
 530 const char * const btrfs_feature_set_names[3] = {
 531         [FEAT_COMPAT]    = "compat",
 532         [FEAT_COMPAT_RO] = "compat_ro",
 533         [FEAT_INCOMPAT]  = "incompat",
 534 };
 535
 536 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 537 {
 538         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 539         int len = 0;
 540         int i;
 541         char *str;
 542
 543         str = kmalloc(bufsize, GFP_KERNEL);
 544         if (!str)
 545                 return str;
 546
 547         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 548                 const char *name;
 549
 550                 if (!(flags & (1ULL << i)))
 551                         continue;
 552
 553                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 554                 len += snprintf(str + len, bufsize - len, "%s%s",
 555                                 len ? "," : "", name);
 556         }
 557
 558         return str;
 559 }
 560
 561 static void init_feature_attrs(void)
 562 {
 563         struct btrfs_feature_attr *fa;
 564         int set, i;
 565
 566         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 567                      ARRAY_SIZE(btrfs_feature_attrs));
 568         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 569                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 570
 571         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 572         memset(btrfs_unknown_feature_names, 0,
 573                sizeof(btrfs_unknown_feature_names));
 574
 575         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 576                 struct btrfs_feature_attr *sfa;
 577                 struct attribute *a = btrfs_supported_feature_attrs[i];
 578                 int bit;
 579                 sfa = attr_to_btrfs_feature_attr(a);
 580                 bit = ilog2(sfa->feature_bit);
 581                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 582
 583                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 584         }
 585
 586         for (set = 0; set < FEAT_MAX; set++) {
 587                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 588                         char *name = btrfs_unknown_feature_names[set][i];
 589                         fa = &btrfs_feature_attrs[set][i];
 590
 591                         if (fa->kobj_attr.attr.name)
 592                                 continue;
 593
 594                         snprintf(name, 13, "%s:%u",
 595                                  btrfs_feature_set_names[set], i);
 596
 597                         fa->kobj_attr.attr.name = name;
 598                         fa->kobj_attr.attr.mode = S_IRUGO;
 599                         fa->feature_set = set;
 600                         fa->feature_bit = 1ULL << i;
 601                 }
 602         }
 603 }
 604
 605 int btrfs_kobj_rm_device(struct btrfs_fs_info *fs_info,
 606                 struct btrfs_device *one_device)
 607 {
 608         struct hd_struct *disk;
 609         struct kobject *disk_kobj;
 610
 611         if (!fs_info->device_dir_kobj)
 612                 return -EINVAL;
 613
 614         if (one_device && one_device->bdev) {
 615                 disk = one_device->bdev->bd_part;
 616                 disk_kobj = &part_to_dev(disk)->kobj;
 617
 618                 sysfs_remove_link(fs_info->device_dir_kobj,
 619                                                 disk_kobj->name);
 620         }
 621
 622         return 0;
 623 }
 624
 625 int btrfs_kobj_add_device(struct btrfs_fs_info *fs_info,
 626                 struct btrfs_device *one_device)
 627 {
 628         int error = 0;
 629         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 630         struct btrfs_device *dev;
 631
 632         if (!fs_info->device_dir_kobj)
 633                 fs_info->device_dir_kobj = kobject_create_and_add("devices",
 634                                                 &fs_info->super_kobj);
 635
 636         if (!fs_info->device_dir_kobj)
 637                 return -ENOMEM;
 638
 639         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 640                 struct hd_struct *disk;
 641                 struct kobject *disk_kobj;
 642
 643                 if (!dev->bdev)
 644                         continue;
 645
 646                 if (one_device && one_device != dev)
 647                         continue;
 648
 649                 disk = dev->bdev->bd_part;
 650                 disk_kobj = &part_to_dev(disk)->kobj;
 651
 652                 error = sysfs_create_link(fs_info->device_dir_kobj,
 653                                           disk_kobj, disk_kobj->name);
 654                 if (error)
 655                         break;
 656         }
 657
 658         return error;
 659 }
 660
 661 /* /sys/fs/btrfs/ entry */
 662 static struct kset *btrfs_kset;
 663
 664 /* /sys/kernel/debug/btrfs */
 665 static struct dentry *btrfs_debugfs_root_dentry;
 666
 667 /* Debugging tunables and exported data */
 668 u64 btrfs_debugfs_test;
 669
 670 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 671 {
 672         int error;
 673
 674         init_completion(&fs_info->kobj_unregister);
 675         fs_info->super_kobj.kset = btrfs_kset;
 676         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 677                                      "%pU", fs_info->fsid);
 678         if (error)
 679                 return error;
 680
 681         error = sysfs_create_group(&fs_info->super_kobj,
 682                                    &btrfs_feature_attr_group);
 683         if (error) {
 684                 __btrfs_sysfs_remove_one(fs_info);
 685                 return error;
 686         }
 687
 688         error = addrm_unknown_feature_attrs(fs_info, true);
 689         if (error)
 690                 goto failure;
 691
 692         error = btrfs_kobj_add_device(fs_info, NULL);
 693         if (error)
 694                 goto failure;
 695
 696         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 697                                                   &fs_info->super_kobj);
 698         if (!fs_info->space_info_kobj) {
 699                 error = -ENOMEM;
 700                 goto failure;
 701         }
 702
 703         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 704         if (error)
 705                 goto failure;
 706
 707         return 0;
 708 failure:
 709         btrfs_sysfs_remove_one(fs_info);
 710         return error;
 711 }
 712
 713 static int btrfs_init_debugfs(void)
 714 {
 715 #ifdef CONFIG_DEBUG_FS
 716         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 717         if (!btrfs_debugfs_root_dentry)
 718                 return -ENOMEM;
 719
 720         debugfs_create_u64("test", S_IRUGO | S_IWUGO, btrfs_debugfs_root_dentry,
 721                         &btrfs_debugfs_test);
 722 #endif
 723         return 0;
 724 }
 725
 726 int btrfs_init_sysfs(void)
 727 {
 728         int ret;
 729
 730         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 731         if (!btrfs_kset)
 732                 return -ENOMEM;
 733
 734         ret = btrfs_init_debugfs();
 735         if (ret)
 736                 goto out1;
 737
 738         init_feature_attrs();
 739         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 740         if (ret)
 741                 goto out2;
 742
 743         return 0;
 744 out2:
 745         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 746 out1:
 747         kset_unregister(btrfs_kset);
 748
 749         return ret;
 750 }
 751
 752 void btrfs_exit_sysfs(void)
 753 {
 754         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 755         kset_unregister(btrfs_kset);
 756         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 757 }
 758