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                 printk(KERN_WARNING "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 (fs_info->sb->s_flags & MS_RDONLY)
 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(big_metadata, BIG_METADATA);
 204 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 205 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 206 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 207 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 208 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 209
 210 static struct attribute *btrfs_supported_feature_attrs[] = {
 211         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 212         BTRFS_FEAT_ATTR_PTR(default_subvol),
 213         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 214         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 215         BTRFS_FEAT_ATTR_PTR(big_metadata),
 216         BTRFS_FEAT_ATTR_PTR(extended_iref),
 217         BTRFS_FEAT_ATTR_PTR(raid56),
 218         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 219         BTRFS_FEAT_ATTR_PTR(no_holes),
 220         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 221         NULL
 222 };
 223
 224 static const struct attribute_group btrfs_feature_attr_group = {
 225         .name = "features",
 226         .is_visible = btrfs_feature_visible,
 227         .attrs = btrfs_supported_feature_attrs,
 228 };
 229
 230 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 231 {
 232         u64 val;
 233         if (lock)
 234                 spin_lock(lock);
 235         val = *value_ptr;
 236         if (lock)
 237                 spin_unlock(lock);
 238         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 239 }
 240
 241 static ssize_t global_rsv_size_show(struct kobject *kobj,
 242                                     struct kobj_attribute *ka, char *buf)
 243 {
 244         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 245         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 246         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 247 }
 248 BTRFS_ATTR(global_rsv_size, global_rsv_size_show);
 249
 250 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 251                                         struct kobj_attribute *a, char *buf)
 252 {
 253         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 254         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 255         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 256 }
 257 BTRFS_ATTR(global_rsv_reserved, global_rsv_reserved_show);
 258
 259 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 260 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 261
 262 static ssize_t raid_bytes_show(struct kobject *kobj,
 263                                struct kobj_attribute *attr, char *buf);
 264 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 265 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 266
 267 static ssize_t raid_bytes_show(struct kobject *kobj,
 268                                struct kobj_attribute *attr, char *buf)
 269
 270 {
 271         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 272         struct btrfs_block_group_cache *block_group;
 273         int index = to_raid_kobj(kobj)->raid_type;
 274         u64 val = 0;
 275
 276         down_read(&sinfo->groups_sem);
 277         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 278                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
 279                         val += block_group->key.offset;
 280                 else
 281                         val += btrfs_block_group_used(&block_group->item);
 282         }
 283         up_read(&sinfo->groups_sem);
 284         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 285 }
 286
 287 static struct attribute *raid_attributes[] = {
 288         BTRFS_RAID_ATTR_PTR(total_bytes),
 289         BTRFS_RAID_ATTR_PTR(used_bytes),
 290         NULL
 291 };
 292
 293 static void release_raid_kobj(struct kobject *kobj)
 294 {
 295         kfree(to_raid_kobj(kobj));
 296 }
 297
 298 struct kobj_type btrfs_raid_ktype = {
 299         .sysfs_ops = &kobj_sysfs_ops,
 300         .release = release_raid_kobj,
 301         .default_attrs = raid_attributes,
 302 };
 303
 304 #define SPACE_INFO_ATTR(field)                                          \
 305 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 306                                              struct kobj_attribute *a,  \
 307                                              char *buf)                 \
 308 {                                                                       \
 309         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 310         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 311 }                                                                       \
 312 BTRFS_ATTR(field, btrfs_space_info_show_##field)
 313
 314 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 315                                                        struct kobj_attribute *a,
 316                                                        char *buf)
 317 {
 318         struct btrfs_space_info *sinfo = to_space_info(kobj);
 319         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 320         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 321 }
 322
 323 SPACE_INFO_ATTR(flags);
 324 SPACE_INFO_ATTR(total_bytes);
 325 SPACE_INFO_ATTR(bytes_used);
 326 SPACE_INFO_ATTR(bytes_pinned);
 327 SPACE_INFO_ATTR(bytes_reserved);
 328 SPACE_INFO_ATTR(bytes_may_use);
 329 SPACE_INFO_ATTR(disk_used);
 330 SPACE_INFO_ATTR(disk_total);
 331 BTRFS_ATTR(total_bytes_pinned, btrfs_space_info_show_total_bytes_pinned);
 332
 333 static struct attribute *space_info_attrs[] = {
 334         BTRFS_ATTR_PTR(flags),
 335         BTRFS_ATTR_PTR(total_bytes),
 336         BTRFS_ATTR_PTR(bytes_used),
 337         BTRFS_ATTR_PTR(bytes_pinned),
 338         BTRFS_ATTR_PTR(bytes_reserved),
 339         BTRFS_ATTR_PTR(bytes_may_use),
 340         BTRFS_ATTR_PTR(disk_used),
 341         BTRFS_ATTR_PTR(disk_total),
 342         BTRFS_ATTR_PTR(total_bytes_pinned),
 343         NULL,
 344 };
 345
 346 static void space_info_release(struct kobject *kobj)
 347 {
 348         struct btrfs_space_info *sinfo = to_space_info(kobj);
 349         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 350         kfree(sinfo);
 351 }
 352
 353 struct kobj_type space_info_ktype = {
 354         .sysfs_ops = &kobj_sysfs_ops,
 355         .release = space_info_release,
 356         .default_attrs = space_info_attrs,
 357 };
 358
 359 static const struct attribute *allocation_attrs[] = {
 360         BTRFS_ATTR_PTR(global_rsv_reserved),
 361         BTRFS_ATTR_PTR(global_rsv_size),
 362         NULL,
 363 };
 364
 365 static ssize_t btrfs_label_show(struct kobject *kobj,
 366                                 struct kobj_attribute *a, char *buf)
 367 {
 368         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 369         char *label = fs_info->super_copy->label;
 370         ssize_t ret;
 371
 372         spin_lock(&fs_info->super_lock);
 373         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 374         spin_unlock(&fs_info->super_lock);
 375
 376         return ret;
 377 }
 378
 379 static ssize_t btrfs_label_store(struct kobject *kobj,
 380                                  struct kobj_attribute *a,
 381                                  const char *buf, size_t len)
 382 {
 383         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 384         size_t p_len;
 385
 386         if (!fs_info)
 387                 return -EPERM;
 388
 389         if (fs_info->sb->s_flags & MS_RDONLY)
 390                 return -EROFS;
 391
 392         /*
 393          * p_len is the len until the first occurrence of either
 394          * '\n' or '\0'
 395          */
 396         p_len = strcspn(buf, "\n");
 397
 398         if (p_len >= BTRFS_LABEL_SIZE)
 399                 return -EINVAL;
 400
 401         spin_lock(&fs_info->super_lock);
 402         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 403         memcpy(fs_info->super_copy->label, buf, p_len);
 404         spin_unlock(&fs_info->super_lock);
 405
 406         /*
 407          * We don't want to do full transaction commit from inside sysfs
 408          */
 409         btrfs_set_pending(fs_info, COMMIT);
 410         wake_up_process(fs_info->transaction_kthread);
 411
 412         return len;
 413 }
 414 BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
 415
 416 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 417                                 struct kobj_attribute *a, char *buf)
 418 {
 419         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 420
 421         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 422 }
 423
 424 BTRFS_ATTR(nodesize, btrfs_nodesize_show);
 425
 426 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 427                                 struct kobj_attribute *a, char *buf)
 428 {
 429         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 430
 431         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 432 }
 433
 434 BTRFS_ATTR(sectorsize, btrfs_sectorsize_show);
 435
 436 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 437                                 struct kobj_attribute *a, char *buf)
 438 {
 439         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 440
 441         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 442 }
 443
 444 BTRFS_ATTR(clone_alignment, btrfs_clone_alignment_show);
 445
 446 static const struct attribute *btrfs_attrs[] = {
 447         BTRFS_ATTR_PTR(label),
 448         BTRFS_ATTR_PTR(nodesize),
 449         BTRFS_ATTR_PTR(sectorsize),
 450         BTRFS_ATTR_PTR(clone_alignment),
 451         NULL,
 452 };
 453
 454 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 455 {
 456         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 457
 458         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 459         complete(&fs_devs->kobj_unregister);
 460 }
 461
 462 static struct kobj_type btrfs_ktype = {
 463         .sysfs_ops      = &kobj_sysfs_ops,
 464         .release        = btrfs_release_fsid_kobj,
 465 };
 466
 467 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 468 {
 469         if (kobj->ktype != &btrfs_ktype)
 470                 return NULL;
 471         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 472 }
 473
 474 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 475 {
 476         if (kobj->ktype != &btrfs_ktype)
 477                 return NULL;
 478         return to_fs_devs(kobj)->fs_info;
 479 }
 480
 481 #define NUM_FEATURE_BITS 64
 482 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 483 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 484
 485 static const u64 supported_feature_masks[3] = {
 486         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 487         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 488         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 489 };
 490
 491 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 492 {
 493         int set;
 494
 495         for (set = 0; set < FEAT_MAX; set++) {
 496                 int i;
 497                 struct attribute *attrs[2];
 498                 struct attribute_group agroup = {
 499                         .name = "features",
 500                         .attrs = attrs,
 501                 };
 502                 u64 features = get_features(fs_info, set);
 503                 features &= ~supported_feature_masks[set];
 504
 505                 if (!features)
 506                         continue;
 507
 508                 attrs[1] = NULL;
 509                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 510                         struct btrfs_feature_attr *fa;
 511
 512                         if (!(features & (1ULL << i)))
 513                                 continue;
 514
 515                         fa = &btrfs_feature_attrs[set][i];
 516                         attrs[0] = &fa->kobj_attr.attr;
 517                         if (add) {
 518                                 int ret;
 519                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 520                                                         &agroup);
 521                                 if (ret)
 522                                         return ret;
 523                         } else
 524                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 525                                                     &agroup);
 526                 }
 527
 528         }
 529         return 0;
 530 }
 531
 532 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 533 {
 534         if (fs_devs->device_dir_kobj) {
 535                 kobject_del(fs_devs->device_dir_kobj);
 536                 kobject_put(fs_devs->device_dir_kobj);
 537                 fs_devs->device_dir_kobj = NULL;
 538         }
 539
 540         if (fs_devs->fsid_kobj.state_initialized) {
 541                 kobject_del(&fs_devs->fsid_kobj);
 542                 kobject_put(&fs_devs->fsid_kobj);
 543                 wait_for_completion(&fs_devs->kobj_unregister);
 544         }
 545 }
 546
 547 /* when fs_devs is NULL it will remove all fsid kobject */
 548 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 549 {
 550         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 551
 552         if (fs_devs) {
 553                 __btrfs_sysfs_remove_fsid(fs_devs);
 554                 return;
 555         }
 556
 557         list_for_each_entry(fs_devs, fs_uuids, list) {
 558                 __btrfs_sysfs_remove_fsid(fs_devs);
 559         }
 560 }
 561
 562 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 563 {
 564         btrfs_reset_fs_info_ptr(fs_info);
 565
 566         if (fs_info->space_info_kobj) {
 567                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 568                 kobject_del(fs_info->space_info_kobj);
 569                 kobject_put(fs_info->space_info_kobj);
 570         }
 571         addrm_unknown_feature_attrs(fs_info, false);
 572         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 573         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 574         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 575 }
 576
 577 const char * const btrfs_feature_set_names[3] = {
 578         [FEAT_COMPAT]    = "compat",
 579         [FEAT_COMPAT_RO] = "compat_ro",
 580         [FEAT_INCOMPAT]  = "incompat",
 581 };
 582
 583 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 584 {
 585         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 586         int len = 0;
 587         int i;
 588         char *str;
 589
 590         str = kmalloc(bufsize, GFP_KERNEL);
 591         if (!str)
 592                 return str;
 593
 594         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 595                 const char *name;
 596
 597                 if (!(flags & (1ULL << i)))
 598                         continue;
 599
 600                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 601                 len += snprintf(str + len, bufsize - len, "%s%s",
 602                                 len ? "," : "", name);
 603         }
 604
 605         return str;
 606 }
 607
 608 static void init_feature_attrs(void)
 609 {
 610         struct btrfs_feature_attr *fa;
 611         int set, i;
 612
 613         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 614                      ARRAY_SIZE(btrfs_feature_attrs));
 615         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 616                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 617
 618         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 619         memset(btrfs_unknown_feature_names, 0,
 620                sizeof(btrfs_unknown_feature_names));
 621
 622         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 623                 struct btrfs_feature_attr *sfa;
 624                 struct attribute *a = btrfs_supported_feature_attrs[i];
 625                 int bit;
 626                 sfa = attr_to_btrfs_feature_attr(a);
 627                 bit = ilog2(sfa->feature_bit);
 628                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 629
 630                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 631         }
 632
 633         for (set = 0; set < FEAT_MAX; set++) {
 634                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 635                         char *name = btrfs_unknown_feature_names[set][i];
 636                         fa = &btrfs_feature_attrs[set][i];
 637
 638                         if (fa->kobj_attr.attr.name)
 639                                 continue;
 640
 641                         snprintf(name, 13, "%s:%u",
 642                                  btrfs_feature_set_names[set], i);
 643
 644                         fa->kobj_attr.attr.name = name;
 645                         fa->kobj_attr.attr.mode = S_IRUGO;
 646                         fa->feature_set = set;
 647                         fa->feature_bit = 1ULL << i;
 648                 }
 649         }
 650 }
 651
 652 /* when one_device is NULL, it removes all device links */
 653
 654 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 655                 struct btrfs_device *one_device)
 656 {
 657         struct hd_struct *disk;
 658         struct kobject *disk_kobj;
 659
 660         if (!fs_devices->device_dir_kobj)
 661                 return -EINVAL;
 662
 663         if (one_device && one_device->bdev) {
 664                 disk = one_device->bdev->bd_part;
 665                 disk_kobj = &part_to_dev(disk)->kobj;
 666
 667                 sysfs_remove_link(fs_devices->device_dir_kobj,
 668                                                 disk_kobj->name);
 669         }
 670
 671         if (one_device)
 672                 return 0;
 673
 674         list_for_each_entry(one_device,
 675                         &fs_devices->devices, dev_list) {
 676                 if (!one_device->bdev)
 677                         continue;
 678                 disk = one_device->bdev->bd_part;
 679                 disk_kobj = &part_to_dev(disk)->kobj;
 680
 681                 sysfs_remove_link(fs_devices->device_dir_kobj,
 682                                                 disk_kobj->name);
 683         }
 684
 685         return 0;
 686 }
 687
 688 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 689 {
 690         if (!fs_devs->device_dir_kobj)
 691                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 692                                                 &fs_devs->fsid_kobj);
 693
 694         if (!fs_devs->device_dir_kobj)
 695                 return -ENOMEM;
 696
 697         return 0;
 698 }
 699
 700 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 701                                 struct btrfs_device *one_device)
 702 {
 703         int error = 0;
 704         struct btrfs_device *dev;
 705
 706         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 707                 struct hd_struct *disk;
 708                 struct kobject *disk_kobj;
 709
 710                 if (!dev->bdev)
 711                         continue;
 712
 713                 if (one_device && one_device != dev)
 714                         continue;
 715
 716                 disk = dev->bdev->bd_part;
 717                 disk_kobj = &part_to_dev(disk)->kobj;
 718
 719                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 720                                           disk_kobj, disk_kobj->name);
 721                 if (error)
 722                         break;
 723         }
 724
 725         return error;
 726 }
 727
 728 /* /sys/fs/btrfs/ entry */
 729 static struct kset *btrfs_kset;
 730
 731 /* /sys/kernel/debug/btrfs */
 732 static struct dentry *btrfs_debugfs_root_dentry;
 733
 734 /* Debugging tunables and exported data */
 735 u64 btrfs_debugfs_test;
 736
 737 /*
 738  * Can be called by the device discovery thread.
 739  * And parent can be specified for seed device
 740  */
 741 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 742                                 struct kobject *parent)
 743 {
 744         int error;
 745
 746         init_completion(&fs_devs->kobj_unregister);
 747         fs_devs->fsid_kobj.kset = btrfs_kset;
 748         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 749                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 750         return error;
 751 }
 752
 753 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 754 {
 755         int error;
 756         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 757         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 758
 759         btrfs_set_fs_info_ptr(fs_info);
 760
 761         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 762         if (error)
 763                 return error;
 764
 765         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 766         if (error) {
 767                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 768                 return error;
 769         }
 770
 771         error = sysfs_create_group(fsid_kobj,
 772                                    &btrfs_feature_attr_group);
 773         if (error)
 774                 goto failure;
 775
 776         error = addrm_unknown_feature_attrs(fs_info, true);
 777         if (error)
 778                 goto failure;
 779
 780         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 781                                                   fsid_kobj);
 782         if (!fs_info->space_info_kobj) {
 783                 error = -ENOMEM;
 784                 goto failure;
 785         }
 786
 787         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 788         if (error)
 789                 goto failure;
 790
 791         return 0;
 792 failure:
 793         btrfs_sysfs_remove_mounted(fs_info);
 794         return error;
 795 }
 796
 797
 798 /*
 799  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 800  * values in superblock. Call after any changes to incompat/compat_ro flags
 801  */
 802 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 803                 u64 bit, enum btrfs_feature_set set)
 804 {
 805         struct btrfs_fs_devices *fs_devs;
 806         struct kobject *fsid_kobj;
 807         u64 features;
 808         int ret;
 809
 810         if (!fs_info)
 811                 return;
 812
 813         features = get_features(fs_info, set);
 814         ASSERT(bit & supported_feature_masks[set]);
 815
 816         fs_devs = fs_info->fs_devices;
 817         fsid_kobj = &fs_devs->fsid_kobj;
 818
 819         if (!fsid_kobj->state_initialized)
 820                 return;
 821
 822         /*
 823          * FIXME: this is too heavy to update just one value, ideally we'd like
 824          * to use sysfs_update_group but some refactoring is needed first.
 825          */
 826         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 827         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 828 }
 829
 830 static int btrfs_init_debugfs(void)
 831 {
 832 #ifdef CONFIG_DEBUG_FS
 833         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 834         if (!btrfs_debugfs_root_dentry)
 835                 return -ENOMEM;
 836
 837         debugfs_create_u64("test", S_IRUGO | S_IWUGO, btrfs_debugfs_root_dentry,
 838                         &btrfs_debugfs_test);
 839 #endif
 840         return 0;
 841 }
 842
 843 int btrfs_init_sysfs(void)
 844 {
 845         int ret;
 846
 847         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 848         if (!btrfs_kset)
 849                 return -ENOMEM;
 850
 851         ret = btrfs_init_debugfs();
 852         if (ret)
 853                 goto out1;
 854
 855         init_feature_attrs();
 856         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 857         if (ret)
 858                 goto out2;
 859
 860         return 0;
 861 out2:
 862         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 863 out1:
 864         kset_unregister(btrfs_kset);
 865
 866         return ret;
 867 }
 868
 869 void btrfs_exit_sysfs(void)
 870 {
 871         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 872         kset_unregister(btrfs_kset);
 873         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 874 }
 875