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 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  37
  38 static u64 get_features(struct btrfs_fs_info *fs_info,
  39                         enum btrfs_feature_set set)
  40 {
  41         struct btrfs_super_block *disk_super = fs_info->super_copy;
  42         if (set == FEAT_COMPAT)
  43                 return btrfs_super_compat_flags(disk_super);
  44         else if (set == FEAT_COMPAT_RO)
  45                 return btrfs_super_compat_ro_flags(disk_super);
  46         else
  47                 return btrfs_super_incompat_flags(disk_super);
  48 }
  49
  50 static void set_features(struct btrfs_fs_info *fs_info,
  51                          enum btrfs_feature_set set, u64 features)
  52 {
  53         struct btrfs_super_block *disk_super = fs_info->super_copy;
  54         if (set == FEAT_COMPAT)
  55                 btrfs_set_super_compat_flags(disk_super, features);
  56         else if (set == FEAT_COMPAT_RO)
  57                 btrfs_set_super_compat_ro_flags(disk_super, features);
  58         else
  59                 btrfs_set_super_incompat_flags(disk_super, features);
  60 }
  61
  62 static int can_modify_feature(struct btrfs_feature_attr *fa)
  63 {
  64         int val = 0;
  65         u64 set, clear;
  66         switch (fa->feature_set) {
  67         case FEAT_COMPAT:
  68                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  69                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  70                 break;
  71         case FEAT_COMPAT_RO:
  72                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  73                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  74                 break;
  75         case FEAT_INCOMPAT:
  76                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  77                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  78                 break;
  79         default:
  80                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
  81                                 fa->feature_set);
  82                 return 0;
  83         }
  84
  85         if (set & fa->feature_bit)
  86                 val |= 1;
  87         if (clear & fa->feature_bit)
  88                 val |= 2;
  89
  90         return val;
  91 }
  92
  93 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  94                                        struct kobj_attribute *a, char *buf)
  95 {
  96         int val = 0;
  97         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  98         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  99         if (fs_info) {
 100                 u64 features = get_features(fs_info, fa->feature_set);
 101                 if (features & fa->feature_bit)
 102                         val = 1;
 103         } else
 104                 val = can_modify_feature(fa);
 105
 106         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 107 }
 108
 109 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 110                                         struct kobj_attribute *a,
 111                                         const char *buf, size_t count)
 112 {
 113         struct btrfs_fs_info *fs_info;
 114         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 115         u64 features, set, clear;
 116         unsigned long val;
 117         int ret;
 118
 119         fs_info = to_fs_info(kobj);
 120         if (!fs_info)
 121                 return -EPERM;
 122
 123         if (sb_rdonly(fs_info->sb))
 124                 return -EROFS;
 125
 126         ret = kstrtoul(skip_spaces(buf), 0, &val);
 127         if (ret)
 128                 return ret;
 129
 130         if (fa->feature_set == FEAT_COMPAT) {
 131                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 132                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 133         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 134                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 135                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 136         } else {
 137                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 138                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 139         }
 140
 141         features = get_features(fs_info, fa->feature_set);
 142
 143         /* Nothing to do */
 144         if ((val && (features & fa->feature_bit)) ||
 145             (!val && !(features & fa->feature_bit)))
 146                 return count;
 147
 148         if ((val && !(set & fa->feature_bit)) ||
 149             (!val && !(clear & fa->feature_bit))) {
 150                 btrfs_info(fs_info,
 151                         "%sabling feature %s on mounted fs is not supported.",
 152                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 153                 return -EPERM;
 154         }
 155
 156         btrfs_info(fs_info, "%s %s feature flag",
 157                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 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         /*
 169          * We don't want to do full transaction commit from inside sysfs
 170          */
 171         btrfs_set_pending(fs_info, COMMIT);
 172         wake_up_process(fs_info->transaction_kthread);
 173
 174         return count;
 175 }
 176
 177 static umode_t btrfs_feature_visible(struct kobject *kobj,
 178                                      struct attribute *attr, int unused)
 179 {
 180         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 181         umode_t mode = attr->mode;
 182
 183         if (fs_info) {
 184                 struct btrfs_feature_attr *fa;
 185                 u64 features;
 186
 187                 fa = attr_to_btrfs_feature_attr(attr);
 188                 features = get_features(fs_info, fa->feature_set);
 189
 190                 if (can_modify_feature(fa))
 191                         mode |= S_IWUSR;
 192                 else if (!(features & fa->feature_bit))
 193                         mode = 0;
 194         }
 195
 196         return mode;
 197 }
 198
 199 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 200 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 201 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 202 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 203 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 204 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 205 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 206 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 207 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 208 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 209 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 210
 211 static struct attribute *btrfs_supported_feature_attrs[] = {
 212         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 213         BTRFS_FEAT_ATTR_PTR(default_subvol),
 214         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 215         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 216         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 217         BTRFS_FEAT_ATTR_PTR(big_metadata),
 218         BTRFS_FEAT_ATTR_PTR(extended_iref),
 219         BTRFS_FEAT_ATTR_PTR(raid56),
 220         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 221         BTRFS_FEAT_ATTR_PTR(no_holes),
 222         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 223         NULL
 224 };
 225
 226 static const struct attribute_group btrfs_feature_attr_group = {
 227         .name = "features",
 228         .is_visible = btrfs_feature_visible,
 229         .attrs = btrfs_supported_feature_attrs,
 230 };
 231
 232 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 233 {
 234         u64 val;
 235         if (lock)
 236                 spin_lock(lock);
 237         val = *value_ptr;
 238         if (lock)
 239                 spin_unlock(lock);
 240         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 241 }
 242
 243 static ssize_t global_rsv_size_show(struct kobject *kobj,
 244                                     struct kobj_attribute *ka, char *buf)
 245 {
 246         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 247         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 248         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 249 }
 250 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 251
 252 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 253                                         struct kobj_attribute *a, char *buf)
 254 {
 255         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 256         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 257         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 258 }
 259 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 260
 261 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 262 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 263
 264 static ssize_t raid_bytes_show(struct kobject *kobj,
 265                                struct kobj_attribute *attr, char *buf);
 266 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 267 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 268
 269 static ssize_t raid_bytes_show(struct kobject *kobj,
 270                                struct kobj_attribute *attr, char *buf)
 271
 272 {
 273         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 274         struct btrfs_block_group_cache *block_group;
 275         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 276         u64 val = 0;
 277
 278         down_read(&sinfo->groups_sem);
 279         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 280                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 281                         val += block_group->key.offset;
 282                 else
 283                         val += btrfs_block_group_used(&block_group->item);
 284         }
 285         up_read(&sinfo->groups_sem);
 286         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 287 }
 288
 289 static struct attribute *raid_attributes[] = {
 290         BTRFS_ATTR_PTR(raid, total_bytes),
 291         BTRFS_ATTR_PTR(raid, used_bytes),
 292         NULL
 293 };
 294
 295 static void release_raid_kobj(struct kobject *kobj)
 296 {
 297         kfree(to_raid_kobj(kobj));
 298 }
 299
 300 struct kobj_type btrfs_raid_ktype = {
 301         .sysfs_ops = &kobj_sysfs_ops,
 302         .release = release_raid_kobj,
 303         .default_attrs = raid_attributes,
 304 };
 305
 306 #define SPACE_INFO_ATTR(field)                                          \
 307 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 308                                              struct kobj_attribute *a,  \
 309                                              char *buf)                 \
 310 {                                                                       \
 311         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 312         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 313 }                                                                       \
 314 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 315
 316 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 317                                                        struct kobj_attribute *a,
 318                                                        char *buf)
 319 {
 320         struct btrfs_space_info *sinfo = to_space_info(kobj);
 321         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 322         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 323 }
 324
 325 SPACE_INFO_ATTR(flags);
 326 SPACE_INFO_ATTR(total_bytes);
 327 SPACE_INFO_ATTR(bytes_used);
 328 SPACE_INFO_ATTR(bytes_pinned);
 329 SPACE_INFO_ATTR(bytes_reserved);
 330 SPACE_INFO_ATTR(bytes_may_use);
 331 SPACE_INFO_ATTR(bytes_readonly);
 332 SPACE_INFO_ATTR(disk_used);
 333 SPACE_INFO_ATTR(disk_total);
 334 BTRFS_ATTR(space_info, total_bytes_pinned,
 335            btrfs_space_info_show_total_bytes_pinned);
 336
 337 static struct attribute *space_info_attrs[] = {
 338         BTRFS_ATTR_PTR(space_info, flags),
 339         BTRFS_ATTR_PTR(space_info, total_bytes),
 340         BTRFS_ATTR_PTR(space_info, bytes_used),
 341         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 342         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 343         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 344         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 345         BTRFS_ATTR_PTR(space_info, disk_used),
 346         BTRFS_ATTR_PTR(space_info, disk_total),
 347         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 348         NULL,
 349 };
 350
 351 static void space_info_release(struct kobject *kobj)
 352 {
 353         struct btrfs_space_info *sinfo = to_space_info(kobj);
 354         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 355         kfree(sinfo);
 356 }
 357
 358 struct kobj_type space_info_ktype = {
 359         .sysfs_ops = &kobj_sysfs_ops,
 360         .release = space_info_release,
 361         .default_attrs = space_info_attrs,
 362 };
 363
 364 static const struct attribute *allocation_attrs[] = {
 365         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 366         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 367         NULL,
 368 };
 369
 370 static ssize_t btrfs_label_show(struct kobject *kobj,
 371                                 struct kobj_attribute *a, char *buf)
 372 {
 373         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 374         char *label = fs_info->super_copy->label;
 375         ssize_t ret;
 376
 377         spin_lock(&fs_info->super_lock);
 378         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 379         spin_unlock(&fs_info->super_lock);
 380
 381         return ret;
 382 }
 383
 384 static ssize_t btrfs_label_store(struct kobject *kobj,
 385                                  struct kobj_attribute *a,
 386                                  const char *buf, size_t len)
 387 {
 388         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 389         size_t p_len;
 390
 391         if (!fs_info)
 392                 return -EPERM;
 393
 394         if (sb_rdonly(fs_info->sb))
 395                 return -EROFS;
 396
 397         /*
 398          * p_len is the len until the first occurrence of either
 399          * '\n' or '\0'
 400          */
 401         p_len = strcspn(buf, "\n");
 402
 403         if (p_len >= BTRFS_LABEL_SIZE)
 404                 return -EINVAL;
 405
 406         spin_lock(&fs_info->super_lock);
 407         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 408         memcpy(fs_info->super_copy->label, buf, p_len);
 409         spin_unlock(&fs_info->super_lock);
 410
 411         /*
 412          * We don't want to do full transaction commit from inside sysfs
 413          */
 414         btrfs_set_pending(fs_info, COMMIT);
 415         wake_up_process(fs_info->transaction_kthread);
 416
 417         return len;
 418 }
 419 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 420
 421 static ssize_t btrfs_nodesize_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->nodesize);
 427 }
 428
 429 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 430
 431 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 432                                 struct kobj_attribute *a, char *buf)
 433 {
 434         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 435
 436         return snprintf(buf, PAGE_SIZE, "%u\n",
 437                         fs_info->super_copy->sectorsize);
 438 }
 439
 440 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 441
 442 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 443                                 struct kobj_attribute *a, char *buf)
 444 {
 445         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 446
 447         return snprintf(buf, PAGE_SIZE, "%u\n",
 448                         fs_info->super_copy->sectorsize);
 449 }
 450
 451 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 452
 453 static ssize_t quota_override_show(struct kobject *kobj,
 454                                    struct kobj_attribute *a, char *buf)
 455 {
 456         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 457         int quota_override;
 458
 459         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 460         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 461 }
 462
 463 static ssize_t quota_override_store(struct kobject *kobj,
 464                                     struct kobj_attribute *a,
 465                                     const char *buf, size_t len)
 466 {
 467         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 468         unsigned long knob;
 469         int err;
 470
 471         if (!fs_info)
 472                 return -EPERM;
 473
 474         if (!capable(CAP_SYS_RESOURCE))
 475                 return -EPERM;
 476
 477         err = kstrtoul(buf, 10, &knob);
 478         if (err)
 479                 return err;
 480         if (knob > 1)
 481                 return -EINVAL;
 482
 483         if (knob)
 484                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 485         else
 486                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 487
 488         return len;
 489 }
 490
 491 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 492
 493 static const struct attribute *btrfs_attrs[] = {
 494         BTRFS_ATTR_PTR(, label),
 495         BTRFS_ATTR_PTR(, nodesize),
 496         BTRFS_ATTR_PTR(, sectorsize),
 497         BTRFS_ATTR_PTR(, clone_alignment),
 498         BTRFS_ATTR_PTR(, quota_override),
 499         NULL,
 500 };
 501
 502 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 503 {
 504         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 505
 506         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 507         complete(&fs_devs->kobj_unregister);
 508 }
 509
 510 static struct kobj_type btrfs_ktype = {
 511         .sysfs_ops      = &kobj_sysfs_ops,
 512         .release        = btrfs_release_fsid_kobj,
 513 };
 514
 515 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 516 {
 517         if (kobj->ktype != &btrfs_ktype)
 518                 return NULL;
 519         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 520 }
 521
 522 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 523 {
 524         if (kobj->ktype != &btrfs_ktype)
 525                 return NULL;
 526         return to_fs_devs(kobj)->fs_info;
 527 }
 528
 529 #define NUM_FEATURE_BITS 64
 530 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 531 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 532
 533 static const u64 supported_feature_masks[3] = {
 534         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 535         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 536         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 537 };
 538
 539 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 540 {
 541         int set;
 542
 543         for (set = 0; set < FEAT_MAX; set++) {
 544                 int i;
 545                 struct attribute *attrs[2];
 546                 struct attribute_group agroup = {
 547                         .name = "features",
 548                         .attrs = attrs,
 549                 };
 550                 u64 features = get_features(fs_info, set);
 551                 features &= ~supported_feature_masks[set];
 552
 553                 if (!features)
 554                         continue;
 555
 556                 attrs[1] = NULL;
 557                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 558                         struct btrfs_feature_attr *fa;
 559
 560                         if (!(features & (1ULL << i)))
 561                                 continue;
 562
 563                         fa = &btrfs_feature_attrs[set][i];
 564                         attrs[0] = &fa->kobj_attr.attr;
 565                         if (add) {
 566                                 int ret;
 567                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 568                                                         &agroup);
 569                                 if (ret)
 570                                         return ret;
 571                         } else
 572                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 573                                                     &agroup);
 574                 }
 575
 576         }
 577         return 0;
 578 }
 579
 580 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 581 {
 582         if (fs_devs->device_dir_kobj) {
 583                 kobject_del(fs_devs->device_dir_kobj);
 584                 kobject_put(fs_devs->device_dir_kobj);
 585                 fs_devs->device_dir_kobj = NULL;
 586         }
 587
 588         if (fs_devs->fsid_kobj.state_initialized) {
 589                 kobject_del(&fs_devs->fsid_kobj);
 590                 kobject_put(&fs_devs->fsid_kobj);
 591                 wait_for_completion(&fs_devs->kobj_unregister);
 592         }
 593 }
 594
 595 /* when fs_devs is NULL it will remove all fsid kobject */
 596 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 597 {
 598         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 599
 600         if (fs_devs) {
 601                 __btrfs_sysfs_remove_fsid(fs_devs);
 602                 return;
 603         }
 604
 605         list_for_each_entry(fs_devs, fs_uuids, list) {
 606                 __btrfs_sysfs_remove_fsid(fs_devs);
 607         }
 608 }
 609
 610 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 611 {
 612         btrfs_reset_fs_info_ptr(fs_info);
 613
 614         if (fs_info->space_info_kobj) {
 615                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 616                 kobject_del(fs_info->space_info_kobj);
 617                 kobject_put(fs_info->space_info_kobj);
 618         }
 619         addrm_unknown_feature_attrs(fs_info, false);
 620         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 621         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 622         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 623 }
 624
 625 const char * const btrfs_feature_set_names[3] = {
 626         [FEAT_COMPAT]    = "compat",
 627         [FEAT_COMPAT_RO] = "compat_ro",
 628         [FEAT_INCOMPAT]  = "incompat",
 629 };
 630
 631 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 632 {
 633         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 634         int len = 0;
 635         int i;
 636         char *str;
 637
 638         str = kmalloc(bufsize, GFP_KERNEL);
 639         if (!str)
 640                 return str;
 641
 642         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 643                 const char *name;
 644
 645                 if (!(flags & (1ULL << i)))
 646                         continue;
 647
 648                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 649                 len += snprintf(str + len, bufsize - len, "%s%s",
 650                                 len ? "," : "", name);
 651         }
 652
 653         return str;
 654 }
 655
 656 static void init_feature_attrs(void)
 657 {
 658         struct btrfs_feature_attr *fa;
 659         int set, i;
 660
 661         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 662                      ARRAY_SIZE(btrfs_feature_attrs));
 663         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 664                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 665
 666         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 667         memset(btrfs_unknown_feature_names, 0,
 668                sizeof(btrfs_unknown_feature_names));
 669
 670         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 671                 struct btrfs_feature_attr *sfa;
 672                 struct attribute *a = btrfs_supported_feature_attrs[i];
 673                 int bit;
 674                 sfa = attr_to_btrfs_feature_attr(a);
 675                 bit = ilog2(sfa->feature_bit);
 676                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 677
 678                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 679         }
 680
 681         for (set = 0; set < FEAT_MAX; set++) {
 682                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 683                         char *name = btrfs_unknown_feature_names[set][i];
 684                         fa = &btrfs_feature_attrs[set][i];
 685
 686                         if (fa->kobj_attr.attr.name)
 687                                 continue;
 688
 689                         snprintf(name, 13, "%s:%u",
 690                                  btrfs_feature_set_names[set], i);
 691
 692                         fa->kobj_attr.attr.name = name;
 693                         fa->kobj_attr.attr.mode = S_IRUGO;
 694                         fa->feature_set = set;
 695                         fa->feature_bit = 1ULL << i;
 696                 }
 697         }
 698 }
 699
 700 /* when one_device is NULL, it removes all device links */
 701
 702 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 703                 struct btrfs_device *one_device)
 704 {
 705         struct hd_struct *disk;
 706         struct kobject *disk_kobj;
 707
 708         if (!fs_devices->device_dir_kobj)
 709                 return -EINVAL;
 710
 711         if (one_device && one_device->bdev) {
 712                 disk = one_device->bdev->bd_part;
 713                 disk_kobj = &part_to_dev(disk)->kobj;
 714
 715                 sysfs_remove_link(fs_devices->device_dir_kobj,
 716                                                 disk_kobj->name);
 717         }
 718
 719         if (one_device)
 720                 return 0;
 721
 722         list_for_each_entry(one_device,
 723                         &fs_devices->devices, dev_list) {
 724                 if (!one_device->bdev)
 725                         continue;
 726                 disk = one_device->bdev->bd_part;
 727                 disk_kobj = &part_to_dev(disk)->kobj;
 728
 729                 sysfs_remove_link(fs_devices->device_dir_kobj,
 730                                                 disk_kobj->name);
 731         }
 732
 733         return 0;
 734 }
 735
 736 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 737 {
 738         if (!fs_devs->device_dir_kobj)
 739                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 740                                                 &fs_devs->fsid_kobj);
 741
 742         if (!fs_devs->device_dir_kobj)
 743                 return -ENOMEM;
 744
 745         return 0;
 746 }
 747
 748 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 749                                 struct btrfs_device *one_device)
 750 {
 751         int error = 0;
 752         struct btrfs_device *dev;
 753
 754         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 755                 struct hd_struct *disk;
 756                 struct kobject *disk_kobj;
 757
 758                 if (!dev->bdev)
 759                         continue;
 760
 761                 if (one_device && one_device != dev)
 762                         continue;
 763
 764                 disk = dev->bdev->bd_part;
 765                 disk_kobj = &part_to_dev(disk)->kobj;
 766
 767                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 768                                           disk_kobj, disk_kobj->name);
 769                 if (error)
 770                         break;
 771         }
 772
 773         return error;
 774 }
 775
 776 /* /sys/fs/btrfs/ entry */
 777 static struct kset *btrfs_kset;
 778
 779 /* /sys/kernel/debug/btrfs */
 780 static struct dentry *btrfs_debugfs_root_dentry;
 781
 782 /* Debugging tunables and exported data */
 783 u64 btrfs_debugfs_test;
 784
 785 /*
 786  * Can be called by the device discovery thread.
 787  * And parent can be specified for seed device
 788  */
 789 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 790                                 struct kobject *parent)
 791 {
 792         int error;
 793
 794         init_completion(&fs_devs->kobj_unregister);
 795         fs_devs->fsid_kobj.kset = btrfs_kset;
 796         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 797                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 798         return error;
 799 }
 800
 801 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 802 {
 803         int error;
 804         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 805         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 806
 807         btrfs_set_fs_info_ptr(fs_info);
 808
 809         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 810         if (error)
 811                 return error;
 812
 813         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 814         if (error) {
 815                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 816                 return error;
 817         }
 818
 819         error = sysfs_create_group(fsid_kobj,
 820                                    &btrfs_feature_attr_group);
 821         if (error)
 822                 goto failure;
 823
 824         error = addrm_unknown_feature_attrs(fs_info, true);
 825         if (error)
 826                 goto failure;
 827
 828         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 829                                                   fsid_kobj);
 830         if (!fs_info->space_info_kobj) {
 831                 error = -ENOMEM;
 832                 goto failure;
 833         }
 834
 835         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 836         if (error)
 837                 goto failure;
 838
 839         return 0;
 840 failure:
 841         btrfs_sysfs_remove_mounted(fs_info);
 842         return error;
 843 }
 844
 845
 846 /*
 847  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 848  * values in superblock. Call after any changes to incompat/compat_ro flags
 849  */
 850 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 851                 u64 bit, enum btrfs_feature_set set)
 852 {
 853         struct btrfs_fs_devices *fs_devs;
 854         struct kobject *fsid_kobj;
 855         u64 features;
 856         int ret;
 857
 858         if (!fs_info)
 859                 return;
 860
 861         features = get_features(fs_info, set);
 862         ASSERT(bit & supported_feature_masks[set]);
 863
 864         fs_devs = fs_info->fs_devices;
 865         fsid_kobj = &fs_devs->fsid_kobj;
 866
 867         if (!fsid_kobj->state_initialized)
 868                 return;
 869
 870         /*
 871          * FIXME: this is too heavy to update just one value, ideally we'd like
 872          * to use sysfs_update_group but some refactoring is needed first.
 873          */
 874         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 875         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 876 }
 877
 878 static int btrfs_init_debugfs(void)
 879 {
 880 #ifdef CONFIG_DEBUG_FS
 881         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 882         if (!btrfs_debugfs_root_dentry)
 883                 return -ENOMEM;
 884
 885         /*
 886          * Example code, how to export data through debugfs.
 887          *
 888          * file:        /sys/kernel/debug/btrfs/test
 889          * contents of: btrfs_debugfs_test
 890          */
 891 #ifdef CONFIG_BTRFS_DEBUG
 892         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 893                         &btrfs_debugfs_test);
 894 #endif
 895
 896 #endif
 897         return 0;
 898 }
 899
 900 int __init btrfs_init_sysfs(void)
 901 {
 902         int ret;
 903
 904         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 905         if (!btrfs_kset)
 906                 return -ENOMEM;
 907
 908         ret = btrfs_init_debugfs();
 909         if (ret)
 910                 goto out1;
 911
 912         init_feature_attrs();
 913         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 914         if (ret)
 915                 goto out2;
 916
 917         return 0;
 918 out2:
 919         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 920 out1:
 921         kset_unregister(btrfs_kset);
 922
 923         return ret;
 924 }
 925
 926 void __cold btrfs_exit_sysfs(void)
 927 {
 928         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 929         kset_unregister(btrfs_kset);
 930         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 931 }
 932