fs/btrfs/sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/mm.h>
   8 #include <linux/slab.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/completion.h>
  11 #include <linux/bug.h>
  12
  13 #include "ctree.h"
  14 #include "disk-io.h"
  15 #include "transaction.h"
  16 #include "sysfs.h"
  17 #include "volumes.h"
  18 #include "space-info.h"
  19 #include "block-group.h"
  20
  21 struct btrfs_feature_attr {
  22         struct kobj_attribute kobj_attr;
  23         enum btrfs_feature_set feature_set;
  24         u64 feature_bit;
  25 };
  26
  27 /* For raid type sysfs entries */
  28 struct raid_kobject {
  29         u64 flags;
  30         struct kobject kobj;
  31 };
  32
  33 #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)                   \
  34 {                                                                       \
  35         .attr   = { .name = __stringify(_name), .mode = _mode },        \
  36         .show   = _show,                                                \
  37         .store  = _store,                                               \
  38 }
  39
  40 #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)                    \
  41         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  42                         __INIT_KOBJ_ATTR(_name, 0644, _show, _store)
  43
  44 #define BTRFS_ATTR(_prefix, _name, _show)                               \
  45         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  46                         __INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
  47
  48 #define BTRFS_ATTR_PTR(_prefix, _name)                                  \
  49         (&btrfs_attr_##_prefix##_##_name.attr)
  50
  51 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
  52 static struct btrfs_feature_attr btrfs_attr_features_##_name = {             \
  53         .kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,                        \
  54                                       btrfs_feature_attr_show,               \
  55                                       btrfs_feature_attr_store),             \
  56         .feature_set    = _feature_set,                                      \
  57         .feature_bit    = _feature_prefix ##_## _feature_bit,                \
  58 }
  59 #define BTRFS_FEAT_ATTR_PTR(_name)                                           \
  60         (&btrfs_attr_features_##_name.kobj_attr.attr)
  61
  62 #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
  63         BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
  64 #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
  65         BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
  66 #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
  67         BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
  68
  69 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  70 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  71
  72 static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
  73 {
  74         return container_of(a, struct btrfs_feature_attr, kobj_attr);
  75 }
  76
  77 static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
  78 {
  79         return container_of(attr, struct kobj_attribute, attr);
  80 }
  81
  82 static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
  83                 struct attribute *attr)
  84 {
  85         return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
  86 }
  87
  88 static u64 get_features(struct btrfs_fs_info *fs_info,
  89                         enum btrfs_feature_set set)
  90 {
  91         struct btrfs_super_block *disk_super = fs_info->super_copy;
  92         if (set == FEAT_COMPAT)
  93                 return btrfs_super_compat_flags(disk_super);
  94         else if (set == FEAT_COMPAT_RO)
  95                 return btrfs_super_compat_ro_flags(disk_super);
  96         else
  97                 return btrfs_super_incompat_flags(disk_super);
  98 }
  99
 100 static void set_features(struct btrfs_fs_info *fs_info,
 101                          enum btrfs_feature_set set, u64 features)
 102 {
 103         struct btrfs_super_block *disk_super = fs_info->super_copy;
 104         if (set == FEAT_COMPAT)
 105                 btrfs_set_super_compat_flags(disk_super, features);
 106         else if (set == FEAT_COMPAT_RO)
 107                 btrfs_set_super_compat_ro_flags(disk_super, features);
 108         else
 109                 btrfs_set_super_incompat_flags(disk_super, features);
 110 }
 111
 112 static int can_modify_feature(struct btrfs_feature_attr *fa)
 113 {
 114         int val = 0;
 115         u64 set, clear;
 116         switch (fa->feature_set) {
 117         case FEAT_COMPAT:
 118                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 119                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 120                 break;
 121         case FEAT_COMPAT_RO:
 122                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 123                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 124                 break;
 125         case FEAT_INCOMPAT:
 126                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 127                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 128                 break;
 129         default:
 130                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
 131                                 fa->feature_set);
 132                 return 0;
 133         }
 134
 135         if (set & fa->feature_bit)
 136                 val |= 1;
 137         if (clear & fa->feature_bit)
 138                 val |= 2;
 139
 140         return val;
 141 }
 142
 143 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
 144                                        struct kobj_attribute *a, char *buf)
 145 {
 146         int val = 0;
 147         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 148         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 149         if (fs_info) {
 150                 u64 features = get_features(fs_info, fa->feature_set);
 151                 if (features & fa->feature_bit)
 152                         val = 1;
 153         } else
 154                 val = can_modify_feature(fa);
 155
 156         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 157 }
 158
 159 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 160                                         struct kobj_attribute *a,
 161                                         const char *buf, size_t count)
 162 {
 163         struct btrfs_fs_info *fs_info;
 164         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 165         u64 features, set, clear;
 166         unsigned long val;
 167         int ret;
 168
 169         fs_info = to_fs_info(kobj);
 170         if (!fs_info)
 171                 return -EPERM;
 172
 173         if (sb_rdonly(fs_info->sb))
 174                 return -EROFS;
 175
 176         ret = kstrtoul(skip_spaces(buf), 0, &val);
 177         if (ret)
 178                 return ret;
 179
 180         if (fa->feature_set == FEAT_COMPAT) {
 181                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 182                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 183         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 184                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 185                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 186         } else {
 187                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 188                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 189         }
 190
 191         features = get_features(fs_info, fa->feature_set);
 192
 193         /* Nothing to do */
 194         if ((val && (features & fa->feature_bit)) ||
 195             (!val && !(features & fa->feature_bit)))
 196                 return count;
 197
 198         if ((val && !(set & fa->feature_bit)) ||
 199             (!val && !(clear & fa->feature_bit))) {
 200                 btrfs_info(fs_info,
 201                         "%sabling feature %s on mounted fs is not supported.",
 202                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 203                 return -EPERM;
 204         }
 205
 206         btrfs_info(fs_info, "%s %s feature flag",
 207                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 208
 209         spin_lock(&fs_info->super_lock);
 210         features = get_features(fs_info, fa->feature_set);
 211         if (val)
 212                 features |= fa->feature_bit;
 213         else
 214                 features &= ~fa->feature_bit;
 215         set_features(fs_info, fa->feature_set, features);
 216         spin_unlock(&fs_info->super_lock);
 217
 218         /*
 219          * We don't want to do full transaction commit from inside sysfs
 220          */
 221         btrfs_set_pending(fs_info, COMMIT);
 222         wake_up_process(fs_info->transaction_kthread);
 223
 224         return count;
 225 }
 226
 227 static umode_t btrfs_feature_visible(struct kobject *kobj,
 228                                      struct attribute *attr, int unused)
 229 {
 230         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 231         umode_t mode = attr->mode;
 232
 233         if (fs_info) {
 234                 struct btrfs_feature_attr *fa;
 235                 u64 features;
 236
 237                 fa = attr_to_btrfs_feature_attr(attr);
 238                 features = get_features(fs_info, fa->feature_set);
 239
 240                 if (can_modify_feature(fa))
 241                         mode |= S_IWUSR;
 242                 else if (!(features & fa->feature_bit))
 243                         mode = 0;
 244         }
 245
 246         return mode;
 247 }
 248
 249 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 250 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 251 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 252 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 253 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 254 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 255 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 256 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 257 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 258 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 259 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
 260 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 261
 262 static struct attribute *btrfs_supported_feature_attrs[] = {
 263         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 264         BTRFS_FEAT_ATTR_PTR(default_subvol),
 265         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 266         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 267         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 268         BTRFS_FEAT_ATTR_PTR(big_metadata),
 269         BTRFS_FEAT_ATTR_PTR(extended_iref),
 270         BTRFS_FEAT_ATTR_PTR(raid56),
 271         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 272         BTRFS_FEAT_ATTR_PTR(no_holes),
 273         BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 274         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 275         NULL
 276 };
 277
 278 /*
 279  * Features which depend on feature bits and may differ between each fs.
 280  *
 281  * /sys/fs/btrfs/features lists all available features of this kernel while
 282  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 283  * can be changed online.
 284  */
 285 static const struct attribute_group btrfs_feature_attr_group = {
 286         .name = "features",
 287         .is_visible = btrfs_feature_visible,
 288         .attrs = btrfs_supported_feature_attrs,
 289 };
 290
 291 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 292                                  struct kobj_attribute *ka, char *buf)
 293 {
 294         return snprintf(buf, PAGE_SIZE, "0\n");
 295 }
 296 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 297
 298 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 299         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 300         NULL
 301 };
 302
 303 /*
 304  * Features which only depend on kernel version.
 305  *
 306  * These are listed in /sys/fs/btrfs/features along with
 307  * btrfs_feature_attr_group
 308  */
 309 static const struct attribute_group btrfs_static_feature_attr_group = {
 310         .name = "features",
 311         .attrs = btrfs_supported_static_feature_attrs,
 312 };
 313
 314 #ifdef CONFIG_BTRFS_DEBUG
 315
 316 /*
 317  * Runtime debugging exported via sysfs
 318  *
 319  * /sys/fs/btrfs/debug - applies to module or all filesystems
 320  * /sys/fs/btrfs/UUID  - applies only to the given filesystem
 321  */
 322 static struct attribute *btrfs_debug_feature_attrs[] = {
 323         NULL
 324 };
 325
 326 static const struct attribute_group btrfs_debug_feature_attr_group = {
 327         .name = "debug",
 328         .attrs = btrfs_debug_feature_attrs,
 329 };
 330
 331 #endif
 332
 333 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 334 {
 335         u64 val;
 336         if (lock)
 337                 spin_lock(lock);
 338         val = *value_ptr;
 339         if (lock)
 340                 spin_unlock(lock);
 341         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 342 }
 343
 344 static ssize_t global_rsv_size_show(struct kobject *kobj,
 345                                     struct kobj_attribute *ka, char *buf)
 346 {
 347         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 348         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 349         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 350 }
 351 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 352
 353 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 354                                         struct kobj_attribute *a, char *buf)
 355 {
 356         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 357         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 358         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 359 }
 360 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 361
 362 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 363 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 364
 365 static ssize_t raid_bytes_show(struct kobject *kobj,
 366                                struct kobj_attribute *attr, char *buf);
 367 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 368 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 369
 370 static ssize_t raid_bytes_show(struct kobject *kobj,
 371                                struct kobj_attribute *attr, char *buf)
 372
 373 {
 374         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 375         struct btrfs_block_group_cache *block_group;
 376         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 377         u64 val = 0;
 378
 379         down_read(&sinfo->groups_sem);
 380         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 381                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 382                         val += block_group->key.offset;
 383                 else
 384                         val += btrfs_block_group_used(&block_group->item);
 385         }
 386         up_read(&sinfo->groups_sem);
 387         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 388 }
 389
 390 static struct attribute *raid_attrs[] = {
 391         BTRFS_ATTR_PTR(raid, total_bytes),
 392         BTRFS_ATTR_PTR(raid, used_bytes),
 393         NULL
 394 };
 395 ATTRIBUTE_GROUPS(raid);
 396
 397 static void release_raid_kobj(struct kobject *kobj)
 398 {
 399         kfree(to_raid_kobj(kobj));
 400 }
 401
 402 static struct kobj_type btrfs_raid_ktype = {
 403         .sysfs_ops = &kobj_sysfs_ops,
 404         .release = release_raid_kobj,
 405         .default_groups = raid_groups,
 406 };
 407
 408 #define SPACE_INFO_ATTR(field)                                          \
 409 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 410                                              struct kobj_attribute *a,  \
 411                                              char *buf)                 \
 412 {                                                                       \
 413         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 414         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 415 }                                                                       \
 416 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 417
 418 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 419                                                        struct kobj_attribute *a,
 420                                                        char *buf)
 421 {
 422         struct btrfs_space_info *sinfo = to_space_info(kobj);
 423         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 424         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 425 }
 426
 427 SPACE_INFO_ATTR(flags);
 428 SPACE_INFO_ATTR(total_bytes);
 429 SPACE_INFO_ATTR(bytes_used);
 430 SPACE_INFO_ATTR(bytes_pinned);
 431 SPACE_INFO_ATTR(bytes_reserved);
 432 SPACE_INFO_ATTR(bytes_may_use);
 433 SPACE_INFO_ATTR(bytes_readonly);
 434 SPACE_INFO_ATTR(disk_used);
 435 SPACE_INFO_ATTR(disk_total);
 436 BTRFS_ATTR(space_info, total_bytes_pinned,
 437            btrfs_space_info_show_total_bytes_pinned);
 438
 439 static struct attribute *space_info_attrs[] = {
 440         BTRFS_ATTR_PTR(space_info, flags),
 441         BTRFS_ATTR_PTR(space_info, total_bytes),
 442         BTRFS_ATTR_PTR(space_info, bytes_used),
 443         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 444         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 445         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 446         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 447         BTRFS_ATTR_PTR(space_info, disk_used),
 448         BTRFS_ATTR_PTR(space_info, disk_total),
 449         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 450         NULL,
 451 };
 452 ATTRIBUTE_GROUPS(space_info);
 453
 454 static void space_info_release(struct kobject *kobj)
 455 {
 456         struct btrfs_space_info *sinfo = to_space_info(kobj);
 457         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 458         kfree(sinfo);
 459 }
 460
 461 static struct kobj_type space_info_ktype = {
 462         .sysfs_ops = &kobj_sysfs_ops,
 463         .release = space_info_release,
 464         .default_groups = space_info_groups,
 465 };
 466
 467 static const struct attribute *allocation_attrs[] = {
 468         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 469         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 470         NULL,
 471 };
 472
 473 static ssize_t btrfs_label_show(struct kobject *kobj,
 474                                 struct kobj_attribute *a, char *buf)
 475 {
 476         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 477         char *label = fs_info->super_copy->label;
 478         ssize_t ret;
 479
 480         spin_lock(&fs_info->super_lock);
 481         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 482         spin_unlock(&fs_info->super_lock);
 483
 484         return ret;
 485 }
 486
 487 static ssize_t btrfs_label_store(struct kobject *kobj,
 488                                  struct kobj_attribute *a,
 489                                  const char *buf, size_t len)
 490 {
 491         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 492         size_t p_len;
 493
 494         if (!fs_info)
 495                 return -EPERM;
 496
 497         if (sb_rdonly(fs_info->sb))
 498                 return -EROFS;
 499
 500         /*
 501          * p_len is the len until the first occurrence of either
 502          * '\n' or '\0'
 503          */
 504         p_len = strcspn(buf, "\n");
 505
 506         if (p_len >= BTRFS_LABEL_SIZE)
 507                 return -EINVAL;
 508
 509         spin_lock(&fs_info->super_lock);
 510         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 511         memcpy(fs_info->super_copy->label, buf, p_len);
 512         spin_unlock(&fs_info->super_lock);
 513
 514         /*
 515          * We don't want to do full transaction commit from inside sysfs
 516          */
 517         btrfs_set_pending(fs_info, COMMIT);
 518         wake_up_process(fs_info->transaction_kthread);
 519
 520         return len;
 521 }
 522 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 523
 524 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 525                                 struct kobj_attribute *a, char *buf)
 526 {
 527         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 528
 529         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 530 }
 531
 532 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 533
 534 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 535                                 struct kobj_attribute *a, char *buf)
 536 {
 537         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 538
 539         return snprintf(buf, PAGE_SIZE, "%u\n",
 540                         fs_info->super_copy->sectorsize);
 541 }
 542
 543 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 544
 545 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 546                                 struct kobj_attribute *a, char *buf)
 547 {
 548         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 549
 550         return snprintf(buf, PAGE_SIZE, "%u\n",
 551                         fs_info->super_copy->sectorsize);
 552 }
 553
 554 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 555
 556 static ssize_t quota_override_show(struct kobject *kobj,
 557                                    struct kobj_attribute *a, char *buf)
 558 {
 559         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 560         int quota_override;
 561
 562         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 563         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 564 }
 565
 566 static ssize_t quota_override_store(struct kobject *kobj,
 567                                     struct kobj_attribute *a,
 568                                     const char *buf, size_t len)
 569 {
 570         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 571         unsigned long knob;
 572         int err;
 573
 574         if (!fs_info)
 575                 return -EPERM;
 576
 577         if (!capable(CAP_SYS_RESOURCE))
 578                 return -EPERM;
 579
 580         err = kstrtoul(buf, 10, &knob);
 581         if (err)
 582                 return err;
 583         if (knob > 1)
 584                 return -EINVAL;
 585
 586         if (knob)
 587                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 588         else
 589                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 590
 591         return len;
 592 }
 593
 594 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 595
 596 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 597                                 struct kobj_attribute *a, char *buf)
 598 {
 599         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 600
 601         return snprintf(buf, PAGE_SIZE, "%pU\n",
 602                         fs_info->fs_devices->metadata_uuid);
 603 }
 604
 605 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 606
 607 static const struct attribute *btrfs_attrs[] = {
 608         BTRFS_ATTR_PTR(, label),
 609         BTRFS_ATTR_PTR(, nodesize),
 610         BTRFS_ATTR_PTR(, sectorsize),
 611         BTRFS_ATTR_PTR(, clone_alignment),
 612         BTRFS_ATTR_PTR(, quota_override),
 613         BTRFS_ATTR_PTR(, metadata_uuid),
 614         NULL,
 615 };
 616
 617 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 618 {
 619         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 620
 621         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 622         complete(&fs_devs->kobj_unregister);
 623 }
 624
 625 static struct kobj_type btrfs_ktype = {
 626         .sysfs_ops      = &kobj_sysfs_ops,
 627         .release        = btrfs_release_fsid_kobj,
 628 };
 629
 630 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 631 {
 632         if (kobj->ktype != &btrfs_ktype)
 633                 return NULL;
 634         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 635 }
 636
 637 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 638 {
 639         if (kobj->ktype != &btrfs_ktype)
 640                 return NULL;
 641         return to_fs_devs(kobj)->fs_info;
 642 }
 643
 644 #define NUM_FEATURE_BITS 64
 645 #define BTRFS_FEATURE_NAME_MAX 13
 646 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 647 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 648
 649 static const u64 supported_feature_masks[FEAT_MAX] = {
 650         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 651         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 652         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 653 };
 654
 655 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 656 {
 657         int set;
 658
 659         for (set = 0; set < FEAT_MAX; set++) {
 660                 int i;
 661                 struct attribute *attrs[2];
 662                 struct attribute_group agroup = {
 663                         .name = "features",
 664                         .attrs = attrs,
 665                 };
 666                 u64 features = get_features(fs_info, set);
 667                 features &= ~supported_feature_masks[set];
 668
 669                 if (!features)
 670                         continue;
 671
 672                 attrs[1] = NULL;
 673                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 674                         struct btrfs_feature_attr *fa;
 675
 676                         if (!(features & (1ULL << i)))
 677                                 continue;
 678
 679                         fa = &btrfs_feature_attrs[set][i];
 680                         attrs[0] = &fa->kobj_attr.attr;
 681                         if (add) {
 682                                 int ret;
 683                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 684                                                         &agroup);
 685                                 if (ret)
 686                                         return ret;
 687                         } else
 688                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 689                                                     &agroup);
 690                 }
 691
 692         }
 693         return 0;
 694 }
 695
 696 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 697 {
 698         if (fs_devs->device_dir_kobj) {
 699                 kobject_del(fs_devs->device_dir_kobj);
 700                 kobject_put(fs_devs->device_dir_kobj);
 701                 fs_devs->device_dir_kobj = NULL;
 702         }
 703
 704         if (fs_devs->fsid_kobj.state_initialized) {
 705                 kobject_del(&fs_devs->fsid_kobj);
 706                 kobject_put(&fs_devs->fsid_kobj);
 707                 wait_for_completion(&fs_devs->kobj_unregister);
 708         }
 709 }
 710
 711 /* when fs_devs is NULL it will remove all fsid kobject */
 712 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 713 {
 714         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 715
 716         if (fs_devs) {
 717                 __btrfs_sysfs_remove_fsid(fs_devs);
 718                 return;
 719         }
 720
 721         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 722                 __btrfs_sysfs_remove_fsid(fs_devs);
 723         }
 724 }
 725
 726 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 727 {
 728         btrfs_reset_fs_info_ptr(fs_info);
 729
 730         if (fs_info->space_info_kobj) {
 731                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 732                 kobject_del(fs_info->space_info_kobj);
 733                 kobject_put(fs_info->space_info_kobj);
 734         }
 735         addrm_unknown_feature_attrs(fs_info, false);
 736         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 737         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 738         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 739 }
 740
 741 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
 742         [FEAT_COMPAT]    = "compat",
 743         [FEAT_COMPAT_RO] = "compat_ro",
 744         [FEAT_INCOMPAT]  = "incompat",
 745 };
 746
 747 const char * const btrfs_feature_set_name(enum btrfs_feature_set set)
 748 {
 749         return btrfs_feature_set_names[set];
 750 }
 751
 752 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 753 {
 754         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 755         int len = 0;
 756         int i;
 757         char *str;
 758
 759         str = kmalloc(bufsize, GFP_KERNEL);
 760         if (!str)
 761                 return str;
 762
 763         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 764                 const char *name;
 765
 766                 if (!(flags & (1ULL << i)))
 767                         continue;
 768
 769                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 770                 len += snprintf(str + len, bufsize - len, "%s%s",
 771                                 len ? "," : "", name);
 772         }
 773
 774         return str;
 775 }
 776
 777 static void init_feature_attrs(void)
 778 {
 779         struct btrfs_feature_attr *fa;
 780         int set, i;
 781
 782         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 783                      ARRAY_SIZE(btrfs_feature_attrs));
 784         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 785                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 786
 787         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 788         memset(btrfs_unknown_feature_names, 0,
 789                sizeof(btrfs_unknown_feature_names));
 790
 791         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 792                 struct btrfs_feature_attr *sfa;
 793                 struct attribute *a = btrfs_supported_feature_attrs[i];
 794                 int bit;
 795                 sfa = attr_to_btrfs_feature_attr(a);
 796                 bit = ilog2(sfa->feature_bit);
 797                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 798
 799                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 800         }
 801
 802         for (set = 0; set < FEAT_MAX; set++) {
 803                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 804                         char *name = btrfs_unknown_feature_names[set][i];
 805                         fa = &btrfs_feature_attrs[set][i];
 806
 807                         if (fa->kobj_attr.attr.name)
 808                                 continue;
 809
 810                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 811                                  btrfs_feature_set_names[set], i);
 812
 813                         fa->kobj_attr.attr.name = name;
 814                         fa->kobj_attr.attr.mode = S_IRUGO;
 815                         fa->feature_set = set;
 816                         fa->feature_bit = 1ULL << i;
 817                 }
 818         }
 819 }
 820
 821 /*
 822  * Create a sysfs entry for a given block group type at path
 823  * /sys/fs/btrfs/UUID/allocation/data/TYPE
 824  */
 825 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group_cache *cache)
 826 {
 827         struct btrfs_fs_info *fs_info = cache->fs_info;
 828         struct btrfs_space_info *space_info = cache->space_info;
 829         struct raid_kobject *rkobj;
 830         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
 831         unsigned int nofs_flag;
 832         int ret;
 833
 834         /*
 835          * Setup a NOFS context because kobject_add(), deep in its call chain,
 836          * does GFP_KERNEL allocations, and we are often called in a context
 837          * where if reclaim is triggered we can deadlock (we are either holding
 838          * a transaction handle or some lock required for a transaction
 839          * commit).
 840          */
 841         nofs_flag = memalloc_nofs_save();
 842
 843         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
 844         if (!rkobj) {
 845                 memalloc_nofs_restore(nofs_flag);
 846                 btrfs_warn(cache->fs_info,
 847                                 "couldn't alloc memory for raid level kobject");
 848                 return;
 849         }
 850
 851         rkobj->flags = cache->flags;
 852         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
 853         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
 854                           btrfs_bg_type_to_raid_name(rkobj->flags));
 855         memalloc_nofs_restore(nofs_flag);
 856         if (ret) {
 857                 kobject_put(&rkobj->kobj);
 858                 btrfs_warn(fs_info,
 859                         "failed to add kobject for block cache, ignoring");
 860                 return;
 861         }
 862
 863         space_info->block_group_kobjs[index] = &rkobj->kobj;
 864 }
 865
 866 /*
 867  * Remove sysfs directories for all block group types of a given space info and
 868  * the space info as well
 869  */
 870 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
 871 {
 872         int i;
 873
 874         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
 875                 struct kobject *kobj;
 876
 877                 kobj = space_info->block_group_kobjs[i];
 878                 space_info->block_group_kobjs[i] = NULL;
 879                 if (kobj) {
 880                         kobject_del(kobj);
 881                         kobject_put(kobj);
 882                 }
 883         }
 884         kobject_del(&space_info->kobj);
 885         kobject_put(&space_info->kobj);
 886 }
 887
 888 static const char *alloc_name(u64 flags)
 889 {
 890         switch (flags) {
 891         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
 892                 return "mixed";
 893         case BTRFS_BLOCK_GROUP_METADATA:
 894                 return "metadata";
 895         case BTRFS_BLOCK_GROUP_DATA:
 896                 return "data";
 897         case BTRFS_BLOCK_GROUP_SYSTEM:
 898                 return "system";
 899         default:
 900                 WARN_ON(1);
 901                 return "invalid-combination";
 902         };
 903 }
 904
 905 /*
 906  * Create a sysfs entry for a space info type at path
 907  * /sys/fs/btrfs/UUID/allocation/TYPE
 908  */
 909 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
 910                                     struct btrfs_space_info *space_info)
 911 {
 912         int ret;
 913
 914         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
 915                                    fs_info->space_info_kobj, "%s",
 916                                    alloc_name(space_info->flags));
 917         if (ret) {
 918                 kobject_put(&space_info->kobj);
 919                 return ret;
 920         }
 921
 922         return 0;
 923 }
 924
 925 /* when one_device is NULL, it removes all device links */
 926
 927 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 928                 struct btrfs_device *one_device)
 929 {
 930         struct hd_struct *disk;
 931         struct kobject *disk_kobj;
 932
 933         if (!fs_devices->device_dir_kobj)
 934                 return -EINVAL;
 935
 936         if (one_device && one_device->bdev) {
 937                 disk = one_device->bdev->bd_part;
 938                 disk_kobj = &part_to_dev(disk)->kobj;
 939
 940                 sysfs_remove_link(fs_devices->device_dir_kobj,
 941                                                 disk_kobj->name);
 942         }
 943
 944         if (one_device)
 945                 return 0;
 946
 947         list_for_each_entry(one_device,
 948                         &fs_devices->devices, dev_list) {
 949                 if (!one_device->bdev)
 950                         continue;
 951                 disk = one_device->bdev->bd_part;
 952                 disk_kobj = &part_to_dev(disk)->kobj;
 953
 954                 sysfs_remove_link(fs_devices->device_dir_kobj,
 955                                                 disk_kobj->name);
 956         }
 957
 958         return 0;
 959 }
 960
 961 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 962 {
 963         if (!fs_devs->device_dir_kobj)
 964                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 965                                                 &fs_devs->fsid_kobj);
 966
 967         if (!fs_devs->device_dir_kobj)
 968                 return -ENOMEM;
 969
 970         return 0;
 971 }
 972
 973 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 974                                 struct btrfs_device *one_device)
 975 {
 976         int error = 0;
 977         struct btrfs_device *dev;
 978         unsigned int nofs_flag;
 979
 980         nofs_flag = memalloc_nofs_save();
 981         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 982                 struct hd_struct *disk;
 983                 struct kobject *disk_kobj;
 984
 985                 if (!dev->bdev)
 986                         continue;
 987
 988                 if (one_device && one_device != dev)
 989                         continue;
 990
 991                 disk = dev->bdev->bd_part;
 992                 disk_kobj = &part_to_dev(disk)->kobj;
 993
 994                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 995                                           disk_kobj, disk_kobj->name);
 996                 if (error)
 997                         break;
 998         }
 999         memalloc_nofs_restore(nofs_flag);
1000
1001         return error;
1002 }
1003
1004 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1005 {
1006         int ret;
1007
1008         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1009         if (ret)
1010                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1011                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1012                         &disk_to_dev(bdev->bd_disk)->kobj);
1013 }
1014
1015 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
1016                                     const u8 *fsid)
1017 {
1018         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1019
1020         /*
1021          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1022          * directory
1023          */
1024         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fsid);
1025         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1026                 btrfs_warn(fs_devices->fs_info,
1027                                 "sysfs: failed to create fsid for sprout");
1028 }
1029
1030 /* /sys/fs/btrfs/ entry */
1031 static struct kset *btrfs_kset;
1032
1033 /*
1034  * Can be called by the device discovery thread.
1035  * And parent can be specified for seed device
1036  */
1037 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
1038                                 struct kobject *parent)
1039 {
1040         int error;
1041
1042         init_completion(&fs_devs->kobj_unregister);
1043         fs_devs->fsid_kobj.kset = btrfs_kset;
1044         error = kobject_init_and_add(&fs_devs->fsid_kobj,
1045                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
1046         if (error) {
1047                 kobject_put(&fs_devs->fsid_kobj);
1048                 return error;
1049         }
1050
1051         return 0;
1052 }
1053
1054 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1055 {
1056         int error;
1057         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1058         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1059
1060         btrfs_set_fs_info_ptr(fs_info);
1061
1062         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
1063         if (error)
1064                 return error;
1065
1066         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1067         if (error) {
1068                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
1069                 return error;
1070         }
1071
1072         error = sysfs_create_group(fsid_kobj,
1073                                    &btrfs_feature_attr_group);
1074         if (error)
1075                 goto failure;
1076
1077 #ifdef CONFIG_BTRFS_DEBUG
1078         error = sysfs_create_group(fsid_kobj,
1079                                    &btrfs_debug_feature_attr_group);
1080         if (error)
1081                 goto failure;
1082 #endif
1083
1084         error = addrm_unknown_feature_attrs(fs_info, true);
1085         if (error)
1086                 goto failure;
1087
1088         fs_info->space_info_kobj = kobject_create_and_add("allocation",
1089                                                   fsid_kobj);
1090         if (!fs_info->space_info_kobj) {
1091                 error = -ENOMEM;
1092                 goto failure;
1093         }
1094
1095         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
1096         if (error)
1097                 goto failure;
1098
1099         return 0;
1100 failure:
1101         btrfs_sysfs_remove_mounted(fs_info);
1102         return error;
1103 }
1104
1105
1106 /*
1107  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
1108  * values in superblock. Call after any changes to incompat/compat_ro flags
1109  */
1110 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
1111                 u64 bit, enum btrfs_feature_set set)
1112 {
1113         struct btrfs_fs_devices *fs_devs;
1114         struct kobject *fsid_kobj;
1115         u64 features;
1116         int ret;
1117
1118         if (!fs_info)
1119                 return;
1120
1121         features = get_features(fs_info, set);
1122         ASSERT(bit & supported_feature_masks[set]);
1123
1124         fs_devs = fs_info->fs_devices;
1125         fsid_kobj = &fs_devs->fsid_kobj;
1126
1127         if (!fsid_kobj->state_initialized)
1128                 return;
1129
1130         /*
1131          * FIXME: this is too heavy to update just one value, ideally we'd like
1132          * to use sysfs_update_group but some refactoring is needed first.
1133          */
1134         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1135         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1136 }
1137
1138 int __init btrfs_init_sysfs(void)
1139 {
1140         int ret;
1141
1142         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1143         if (!btrfs_kset)
1144                 return -ENOMEM;
1145
1146         init_feature_attrs();
1147         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1148         if (ret)
1149                 goto out2;
1150         ret = sysfs_merge_group(&btrfs_kset->kobj,
1151                                 &btrfs_static_feature_attr_group);
1152         if (ret)
1153                 goto out_remove_group;
1154
1155 #ifdef CONFIG_BTRFS_DEBUG
1156         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1157         if (ret) {
1158                 sysfs_unmerge_group(&btrfs_kset->kobj,
1159                                     &btrfs_static_feature_attr_group);
1160                 goto out_remove_group;
1161         }
1162 #endif
1163
1164         return 0;
1165
1166 out_remove_group:
1167         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1168 out2:
1169         kset_unregister(btrfs_kset);
1170
1171         return ret;
1172 }
1173
1174 void __cold btrfs_exit_sysfs(void)
1175 {
1176         sysfs_unmerge_group(&btrfs_kset->kobj,
1177                             &btrfs_static_feature_attr_group);
1178         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1179         kset_unregister(btrfs_kset);
1180 }
1181