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(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(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_RAID_ATTR(total_bytes, raid_bytes_show);
 267 BTRFS_RAID_ATTR(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 = to_raid_kobj(kobj)->raid_type;
 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_RAID_ATTR_PTR(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_RAID_ATTR_PTR(total_bytes),
 291         BTRFS_RAID_ATTR_PTR(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(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(total_bytes_pinned, btrfs_space_info_show_total_bytes_pinned);
 335
 336 static struct attribute *space_info_attrs[] = {
 337         BTRFS_ATTR_PTR(flags),
 338         BTRFS_ATTR_PTR(total_bytes),
 339         BTRFS_ATTR_PTR(bytes_used),
 340         BTRFS_ATTR_PTR(bytes_pinned),
 341         BTRFS_ATTR_PTR(bytes_reserved),
 342         BTRFS_ATTR_PTR(bytes_may_use),
 343         BTRFS_ATTR_PTR(bytes_readonly),
 344         BTRFS_ATTR_PTR(disk_used),
 345         BTRFS_ATTR_PTR(disk_total),
 346         BTRFS_ATTR_PTR(total_bytes_pinned),
 347         NULL,
 348 };
 349
 350 static void space_info_release(struct kobject *kobj)
 351 {
 352         struct btrfs_space_info *sinfo = to_space_info(kobj);
 353         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 354         kfree(sinfo);
 355 }
 356
 357 struct kobj_type space_info_ktype = {
 358         .sysfs_ops = &kobj_sysfs_ops,
 359         .release = space_info_release,
 360         .default_attrs = space_info_attrs,
 361 };
 362
 363 static const struct attribute *allocation_attrs[] = {
 364         BTRFS_ATTR_PTR(global_rsv_reserved),
 365         BTRFS_ATTR_PTR(global_rsv_size),
 366         NULL,
 367 };
 368
 369 static ssize_t btrfs_label_show(struct kobject *kobj,
 370                                 struct kobj_attribute *a, char *buf)
 371 {
 372         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 373         char *label = fs_info->super_copy->label;
 374         ssize_t ret;
 375
 376         spin_lock(&fs_info->super_lock);
 377         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 378         spin_unlock(&fs_info->super_lock);
 379
 380         return ret;
 381 }
 382
 383 static ssize_t btrfs_label_store(struct kobject *kobj,
 384                                  struct kobj_attribute *a,
 385                                  const char *buf, size_t len)
 386 {
 387         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 388         size_t p_len;
 389
 390         if (!fs_info)
 391                 return -EPERM;
 392
 393         if (sb_rdonly(fs_info->sb))
 394                 return -EROFS;
 395
 396         /*
 397          * p_len is the len until the first occurrence of either
 398          * '\n' or '\0'
 399          */
 400         p_len = strcspn(buf, "\n");
 401
 402         if (p_len >= BTRFS_LABEL_SIZE)
 403                 return -EINVAL;
 404
 405         spin_lock(&fs_info->super_lock);
 406         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 407         memcpy(fs_info->super_copy->label, buf, p_len);
 408         spin_unlock(&fs_info->super_lock);
 409
 410         /*
 411          * We don't want to do full transaction commit from inside sysfs
 412          */
 413         btrfs_set_pending(fs_info, COMMIT);
 414         wake_up_process(fs_info->transaction_kthread);
 415
 416         return len;
 417 }
 418 BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
 419
 420 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 421                                 struct kobj_attribute *a, char *buf)
 422 {
 423         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 424
 425         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 426 }
 427
 428 BTRFS_ATTR(nodesize, btrfs_nodesize_show);
 429
 430 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 431                                 struct kobj_attribute *a, char *buf)
 432 {
 433         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 434
 435         return snprintf(buf, PAGE_SIZE, "%u\n",
 436                         fs_info->super_copy->sectorsize);
 437 }
 438
 439 BTRFS_ATTR(sectorsize, btrfs_sectorsize_show);
 440
 441 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 442                                 struct kobj_attribute *a, char *buf)
 443 {
 444         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 445
 446         return snprintf(buf, PAGE_SIZE, "%u\n",
 447                         fs_info->super_copy->sectorsize);
 448 }
 449
 450 BTRFS_ATTR(clone_alignment, btrfs_clone_alignment_show);
 451
 452 static ssize_t quota_override_show(struct kobject *kobj,
 453                                    struct kobj_attribute *a, char *buf)
 454 {
 455         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 456         int quota_override;
 457
 458         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 459         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 460 }
 461
 462 static ssize_t quota_override_store(struct kobject *kobj,
 463                                     struct kobj_attribute *a,
 464                                     const char *buf, size_t len)
 465 {
 466         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 467         unsigned long knob;
 468         int err;
 469
 470         if (!fs_info)
 471                 return -EPERM;
 472
 473         if (!capable(CAP_SYS_RESOURCE))
 474                 return -EPERM;
 475
 476         err = kstrtoul(buf, 10, &knob);
 477         if (err)
 478                 return err;
 479         if (knob > 1)
 480                 return -EINVAL;
 481
 482         if (knob)
 483                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 484         else
 485                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 486
 487         return len;
 488 }
 489
 490 BTRFS_ATTR_RW(quota_override, quota_override_show, quota_override_store);
 491
 492 static const struct attribute *btrfs_attrs[] = {
 493         BTRFS_ATTR_PTR(label),
 494         BTRFS_ATTR_PTR(nodesize),
 495         BTRFS_ATTR_PTR(sectorsize),
 496         BTRFS_ATTR_PTR(clone_alignment),
 497         BTRFS_ATTR_PTR(quota_override),
 498         NULL,
 499 };
 500
 501 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 502 {
 503         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 504
 505         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 506         complete(&fs_devs->kobj_unregister);
 507 }
 508
 509 static struct kobj_type btrfs_ktype = {
 510         .sysfs_ops      = &kobj_sysfs_ops,
 511         .release        = btrfs_release_fsid_kobj,
 512 };
 513
 514 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 515 {
 516         if (kobj->ktype != &btrfs_ktype)
 517                 return NULL;
 518         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 519 }
 520
 521 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 522 {
 523         if (kobj->ktype != &btrfs_ktype)
 524                 return NULL;
 525         return to_fs_devs(kobj)->fs_info;
 526 }
 527
 528 #define NUM_FEATURE_BITS 64
 529 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 530 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 531
 532 static const u64 supported_feature_masks[3] = {
 533         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 534         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 535         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 536 };
 537
 538 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 539 {
 540         int set;
 541
 542         for (set = 0; set < FEAT_MAX; set++) {
 543                 int i;
 544                 struct attribute *attrs[2];
 545                 struct attribute_group agroup = {
 546                         .name = "features",
 547                         .attrs = attrs,
 548                 };
 549                 u64 features = get_features(fs_info, set);
 550                 features &= ~supported_feature_masks[set];
 551
 552                 if (!features)
 553                         continue;
 554
 555                 attrs[1] = NULL;
 556                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 557                         struct btrfs_feature_attr *fa;
 558
 559                         if (!(features & (1ULL << i)))
 560                                 continue;
 561
 562                         fa = &btrfs_feature_attrs[set][i];
 563                         attrs[0] = &fa->kobj_attr.attr;
 564                         if (add) {
 565                                 int ret;
 566                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 567                                                         &agroup);
 568                                 if (ret)
 569                                         return ret;
 570                         } else
 571                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 572                                                     &agroup);
 573                 }
 574
 575         }
 576         return 0;
 577 }
 578
 579 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 580 {
 581         if (fs_devs->device_dir_kobj) {
 582                 kobject_del(fs_devs->device_dir_kobj);
 583                 kobject_put(fs_devs->device_dir_kobj);
 584                 fs_devs->device_dir_kobj = NULL;
 585         }
 586
 587         if (fs_devs->fsid_kobj.state_initialized) {
 588                 kobject_del(&fs_devs->fsid_kobj);
 589                 kobject_put(&fs_devs->fsid_kobj);
 590                 wait_for_completion(&fs_devs->kobj_unregister);
 591         }
 592 }
 593
 594 /* when fs_devs is NULL it will remove all fsid kobject */
 595 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 596 {
 597         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 598
 599         if (fs_devs) {
 600                 __btrfs_sysfs_remove_fsid(fs_devs);
 601                 return;
 602         }
 603
 604         list_for_each_entry(fs_devs, fs_uuids, list) {
 605                 __btrfs_sysfs_remove_fsid(fs_devs);
 606         }
 607 }
 608
 609 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 610 {
 611         btrfs_reset_fs_info_ptr(fs_info);
 612
 613         if (fs_info->space_info_kobj) {
 614                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 615                 kobject_del(fs_info->space_info_kobj);
 616                 kobject_put(fs_info->space_info_kobj);
 617         }
 618         addrm_unknown_feature_attrs(fs_info, false);
 619         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 620         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 621         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 622 }
 623
 624 const char * const btrfs_feature_set_names[3] = {
 625         [FEAT_COMPAT]    = "compat",
 626         [FEAT_COMPAT_RO] = "compat_ro",
 627         [FEAT_INCOMPAT]  = "incompat",
 628 };
 629
 630 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 631 {
 632         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 633         int len = 0;
 634         int i;
 635         char *str;
 636
 637         str = kmalloc(bufsize, GFP_KERNEL);
 638         if (!str)
 639                 return str;
 640
 641         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 642                 const char *name;
 643
 644                 if (!(flags & (1ULL << i)))
 645                         continue;
 646
 647                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 648                 len += snprintf(str + len, bufsize - len, "%s%s",
 649                                 len ? "," : "", name);
 650         }
 651
 652         return str;
 653 }
 654
 655 static void init_feature_attrs(void)
 656 {
 657         struct btrfs_feature_attr *fa;
 658         int set, i;
 659
 660         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 661                      ARRAY_SIZE(btrfs_feature_attrs));
 662         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 663                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 664
 665         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 666         memset(btrfs_unknown_feature_names, 0,
 667                sizeof(btrfs_unknown_feature_names));
 668
 669         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 670                 struct btrfs_feature_attr *sfa;
 671                 struct attribute *a = btrfs_supported_feature_attrs[i];
 672                 int bit;
 673                 sfa = attr_to_btrfs_feature_attr(a);
 674                 bit = ilog2(sfa->feature_bit);
 675                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 676
 677                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 678         }
 679
 680         for (set = 0; set < FEAT_MAX; set++) {
 681                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 682                         char *name = btrfs_unknown_feature_names[set][i];
 683                         fa = &btrfs_feature_attrs[set][i];
 684
 685                         if (fa->kobj_attr.attr.name)
 686                                 continue;
 687
 688                         snprintf(name, 13, "%s:%u",
 689                                  btrfs_feature_set_names[set], i);
 690
 691                         fa->kobj_attr.attr.name = name;
 692                         fa->kobj_attr.attr.mode = S_IRUGO;
 693                         fa->feature_set = set;
 694                         fa->feature_bit = 1ULL << i;
 695                 }
 696         }
 697 }
 698
 699 /* when one_device is NULL, it removes all device links */
 700
 701 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 702                 struct btrfs_device *one_device)
 703 {
 704         struct hd_struct *disk;
 705         struct kobject *disk_kobj;
 706
 707         if (!fs_devices->device_dir_kobj)
 708                 return -EINVAL;
 709
 710         if (one_device && one_device->bdev) {
 711                 disk = one_device->bdev->bd_part;
 712                 disk_kobj = &part_to_dev(disk)->kobj;
 713
 714                 sysfs_remove_link(fs_devices->device_dir_kobj,
 715                                                 disk_kobj->name);
 716         }
 717
 718         if (one_device)
 719                 return 0;
 720
 721         list_for_each_entry(one_device,
 722                         &fs_devices->devices, dev_list) {
 723                 if (!one_device->bdev)
 724                         continue;
 725                 disk = one_device->bdev->bd_part;
 726                 disk_kobj = &part_to_dev(disk)->kobj;
 727
 728                 sysfs_remove_link(fs_devices->device_dir_kobj,
 729                                                 disk_kobj->name);
 730         }
 731
 732         return 0;
 733 }
 734
 735 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 736 {
 737         if (!fs_devs->device_dir_kobj)
 738                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 739                                                 &fs_devs->fsid_kobj);
 740
 741         if (!fs_devs->device_dir_kobj)
 742                 return -ENOMEM;
 743
 744         return 0;
 745 }
 746
 747 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 748                                 struct btrfs_device *one_device)
 749 {
 750         int error = 0;
 751         struct btrfs_device *dev;
 752
 753         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 754                 struct hd_struct *disk;
 755                 struct kobject *disk_kobj;
 756
 757                 if (!dev->bdev)
 758                         continue;
 759
 760                 if (one_device && one_device != dev)
 761                         continue;
 762
 763                 disk = dev->bdev->bd_part;
 764                 disk_kobj = &part_to_dev(disk)->kobj;
 765
 766                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 767                                           disk_kobj, disk_kobj->name);
 768                 if (error)
 769                         break;
 770         }
 771
 772         return error;
 773 }
 774
 775 /* /sys/fs/btrfs/ entry */
 776 static struct kset *btrfs_kset;
 777
 778 /* /sys/kernel/debug/btrfs */
 779 static struct dentry *btrfs_debugfs_root_dentry;
 780
 781 /* Debugging tunables and exported data */
 782 u64 btrfs_debugfs_test;
 783
 784 /*
 785  * Can be called by the device discovery thread.
 786  * And parent can be specified for seed device
 787  */
 788 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 789                                 struct kobject *parent)
 790 {
 791         int error;
 792
 793         init_completion(&fs_devs->kobj_unregister);
 794         fs_devs->fsid_kobj.kset = btrfs_kset;
 795         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 796                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 797         return error;
 798 }
 799
 800 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 801 {
 802         int error;
 803         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 804         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 805
 806         btrfs_set_fs_info_ptr(fs_info);
 807
 808         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 809         if (error)
 810                 return error;
 811
 812         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 813         if (error) {
 814                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 815                 return error;
 816         }
 817
 818         error = sysfs_create_group(fsid_kobj,
 819                                    &btrfs_feature_attr_group);
 820         if (error)
 821                 goto failure;
 822
 823         error = addrm_unknown_feature_attrs(fs_info, true);
 824         if (error)
 825                 goto failure;
 826
 827         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 828                                                   fsid_kobj);
 829         if (!fs_info->space_info_kobj) {
 830                 error = -ENOMEM;
 831                 goto failure;
 832         }
 833
 834         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 835         if (error)
 836                 goto failure;
 837
 838         return 0;
 839 failure:
 840         btrfs_sysfs_remove_mounted(fs_info);
 841         return error;
 842 }
 843
 844
 845 /*
 846  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 847  * values in superblock. Call after any changes to incompat/compat_ro flags
 848  */
 849 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 850                 u64 bit, enum btrfs_feature_set set)
 851 {
 852         struct btrfs_fs_devices *fs_devs;
 853         struct kobject *fsid_kobj;
 854         u64 features;
 855         int ret;
 856
 857         if (!fs_info)
 858                 return;
 859
 860         features = get_features(fs_info, set);
 861         ASSERT(bit & supported_feature_masks[set]);
 862
 863         fs_devs = fs_info->fs_devices;
 864         fsid_kobj = &fs_devs->fsid_kobj;
 865
 866         if (!fsid_kobj->state_initialized)
 867                 return;
 868
 869         /*
 870          * FIXME: this is too heavy to update just one value, ideally we'd like
 871          * to use sysfs_update_group but some refactoring is needed first.
 872          */
 873         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 874         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 875 }
 876
 877 static int btrfs_init_debugfs(void)
 878 {
 879 #ifdef CONFIG_DEBUG_FS
 880         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 881         if (!btrfs_debugfs_root_dentry)
 882                 return -ENOMEM;
 883
 884         /*
 885          * Example code, how to export data through debugfs.
 886          *
 887          * file:        /sys/kernel/debug/btrfs/test
 888          * contents of: btrfs_debugfs_test
 889          */
 890 #ifdef CONFIG_BTRFS_DEBUG
 891         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 892                         &btrfs_debugfs_test);
 893 #endif
 894
 895 #endif
 896         return 0;
 897 }
 898
 899 int btrfs_init_sysfs(void)
 900 {
 901         int ret;
 902
 903         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 904         if (!btrfs_kset)
 905                 return -ENOMEM;
 906
 907         ret = btrfs_init_debugfs();
 908         if (ret)
 909                 goto out1;
 910
 911         init_feature_attrs();
 912         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 913         if (ret)
 914                 goto out2;
 915
 916         return 0;
 917 out2:
 918         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 919 out1:
 920         kset_unregister(btrfs_kset);
 921
 922         return ret;
 923 }
 924
 925 void btrfs_exit_sysfs(void)
 926 {
 927         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 928         kset_unregister(btrfs_kset);
 929         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 930 }
 931