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         ret = kstrtoul(skip_spaces(buf), 0, &val);
 124         if (ret)
 125                 return ret;
 126
 127         if (fa->feature_set == FEAT_COMPAT) {
 128                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 129                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 130         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 131                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 132                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 133         } else {
 134                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 135                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 136         }
 137
 138         features = get_features(fs_info, fa->feature_set);
 139
 140         /* Nothing to do */
 141         if ((val && (features & fa->feature_bit)) ||
 142             (!val && !(features & fa->feature_bit)))
 143                 return count;
 144
 145         if ((val && !(set & fa->feature_bit)) ||
 146             (!val && !(clear & fa->feature_bit))) {
 147                 btrfs_info(fs_info,
 148                         "%sabling feature %s on mounted fs is not supported.",
 149                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 150                 return -EPERM;
 151         }
 152
 153         btrfs_info(fs_info, "%s %s feature flag",
 154                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 155
 156         spin_lock(&fs_info->super_lock);
 157         features = get_features(fs_info, fa->feature_set);
 158         if (val)
 159                 features |= fa->feature_bit;
 160         else
 161                 features &= ~fa->feature_bit;
 162         set_features(fs_info, fa->feature_set, features);
 163         spin_unlock(&fs_info->super_lock);
 164
 165         /*
 166          * We don't want to do full transaction commit from inside sysfs
 167          */
 168         btrfs_set_pending(fs_info, COMMIT);
 169         wake_up_process(fs_info->transaction_kthread);
 170
 171         return count;
 172 }
 173
 174 static umode_t btrfs_feature_visible(struct kobject *kobj,
 175                                      struct attribute *attr, int unused)
 176 {
 177         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 178         umode_t mode = attr->mode;
 179
 180         if (fs_info) {
 181                 struct btrfs_feature_attr *fa;
 182                 u64 features;
 183
 184                 fa = attr_to_btrfs_feature_attr(attr);
 185                 features = get_features(fs_info, fa->feature_set);
 186
 187                 if (can_modify_feature(fa))
 188                         mode |= S_IWUSR;
 189                 else if (!(features & fa->feature_bit))
 190                         mode = 0;
 191         }
 192
 193         return mode;
 194 }
 195
 196 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 197 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 198 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 199 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 200 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 201 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 202 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 203 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 204 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 205
 206 static struct attribute *btrfs_supported_feature_attrs[] = {
 207         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 208         BTRFS_FEAT_ATTR_PTR(default_subvol),
 209         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 210         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 211         BTRFS_FEAT_ATTR_PTR(big_metadata),
 212         BTRFS_FEAT_ATTR_PTR(extended_iref),
 213         BTRFS_FEAT_ATTR_PTR(raid56),
 214         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 215         BTRFS_FEAT_ATTR_PTR(no_holes),
 216         NULL
 217 };
 218
 219 static const struct attribute_group btrfs_feature_attr_group = {
 220         .name = "features",
 221         .is_visible = btrfs_feature_visible,
 222         .attrs = btrfs_supported_feature_attrs,
 223 };
 224
 225 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 226 {
 227         u64 val;
 228         if (lock)
 229                 spin_lock(lock);
 230         val = *value_ptr;
 231         if (lock)
 232                 spin_unlock(lock);
 233         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 234 }
 235
 236 static ssize_t global_rsv_size_show(struct kobject *kobj,
 237                                     struct kobj_attribute *ka, char *buf)
 238 {
 239         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 240         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 241         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 242 }
 243 BTRFS_ATTR(global_rsv_size, global_rsv_size_show);
 244
 245 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 246                                         struct kobj_attribute *a, char *buf)
 247 {
 248         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 249         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 250         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 251 }
 252 BTRFS_ATTR(global_rsv_reserved, global_rsv_reserved_show);
 253
 254 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 255 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 256
 257 static ssize_t raid_bytes_show(struct kobject *kobj,
 258                                struct kobj_attribute *attr, char *buf);
 259 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 260 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 261
 262 static ssize_t raid_bytes_show(struct kobject *kobj,
 263                                struct kobj_attribute *attr, char *buf)
 264
 265 {
 266         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 267         struct btrfs_block_group_cache *block_group;
 268         int index = to_raid_kobj(kobj)->raid_type;
 269         u64 val = 0;
 270
 271         down_read(&sinfo->groups_sem);
 272         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 273                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
 274                         val += block_group->key.offset;
 275                 else
 276                         val += btrfs_block_group_used(&block_group->item);
 277         }
 278         up_read(&sinfo->groups_sem);
 279         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 280 }
 281
 282 static struct attribute *raid_attributes[] = {
 283         BTRFS_RAID_ATTR_PTR(total_bytes),
 284         BTRFS_RAID_ATTR_PTR(used_bytes),
 285         NULL
 286 };
 287
 288 static void release_raid_kobj(struct kobject *kobj)
 289 {
 290         kfree(to_raid_kobj(kobj));
 291 }
 292
 293 struct kobj_type btrfs_raid_ktype = {
 294         .sysfs_ops = &kobj_sysfs_ops,
 295         .release = release_raid_kobj,
 296         .default_attrs = raid_attributes,
 297 };
 298
 299 #define SPACE_INFO_ATTR(field)                                          \
 300 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 301                                              struct kobj_attribute *a,  \
 302                                              char *buf)                 \
 303 {                                                                       \
 304         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 305         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 306 }                                                                       \
 307 BTRFS_ATTR(field, btrfs_space_info_show_##field)
 308
 309 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 310                                                        struct kobj_attribute *a,
 311                                                        char *buf)
 312 {
 313         struct btrfs_space_info *sinfo = to_space_info(kobj);
 314         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 315         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 316 }
 317
 318 SPACE_INFO_ATTR(flags);
 319 SPACE_INFO_ATTR(total_bytes);
 320 SPACE_INFO_ATTR(bytes_used);
 321 SPACE_INFO_ATTR(bytes_pinned);
 322 SPACE_INFO_ATTR(bytes_reserved);
 323 SPACE_INFO_ATTR(bytes_may_use);
 324 SPACE_INFO_ATTR(disk_used);
 325 SPACE_INFO_ATTR(disk_total);
 326 BTRFS_ATTR(total_bytes_pinned, btrfs_space_info_show_total_bytes_pinned);
 327
 328 static struct attribute *space_info_attrs[] = {
 329         BTRFS_ATTR_PTR(flags),
 330         BTRFS_ATTR_PTR(total_bytes),
 331         BTRFS_ATTR_PTR(bytes_used),
 332         BTRFS_ATTR_PTR(bytes_pinned),
 333         BTRFS_ATTR_PTR(bytes_reserved),
 334         BTRFS_ATTR_PTR(bytes_may_use),
 335         BTRFS_ATTR_PTR(disk_used),
 336         BTRFS_ATTR_PTR(disk_total),
 337         BTRFS_ATTR_PTR(total_bytes_pinned),
 338         NULL,
 339 };
 340
 341 static void space_info_release(struct kobject *kobj)
 342 {
 343         struct btrfs_space_info *sinfo = to_space_info(kobj);
 344         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 345         kfree(sinfo);
 346 }
 347
 348 struct kobj_type space_info_ktype = {
 349         .sysfs_ops = &kobj_sysfs_ops,
 350         .release = space_info_release,
 351         .default_attrs = space_info_attrs,
 352 };
 353
 354 static const struct attribute *allocation_attrs[] = {
 355         BTRFS_ATTR_PTR(global_rsv_reserved),
 356         BTRFS_ATTR_PTR(global_rsv_size),
 357         NULL,
 358 };
 359
 360 static ssize_t btrfs_label_show(struct kobject *kobj,
 361                                 struct kobj_attribute *a, char *buf)
 362 {
 363         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 364         char *label = fs_info->super_copy->label;
 365         return snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 366 }
 367
 368 static ssize_t btrfs_label_store(struct kobject *kobj,
 369                                  struct kobj_attribute *a,
 370                                  const char *buf, size_t len)
 371 {
 372         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 373         size_t p_len;
 374
 375         if (fs_info->sb->s_flags & MS_RDONLY)
 376                 return -EROFS;
 377
 378         /*
 379          * p_len is the len until the first occurrence of either
 380          * '\n' or '\0'
 381          */
 382         p_len = strcspn(buf, "\n");
 383
 384         if (p_len >= BTRFS_LABEL_SIZE)
 385                 return -EINVAL;
 386
 387         spin_lock(&fs_info->super_lock);
 388         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 389         memcpy(fs_info->super_copy->label, buf, p_len);
 390         spin_unlock(&fs_info->super_lock);
 391
 392         /*
 393          * We don't want to do full transaction commit from inside sysfs
 394          */
 395         btrfs_set_pending(fs_info, COMMIT);
 396         wake_up_process(fs_info->transaction_kthread);
 397
 398         return len;
 399 }
 400 BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
 401
 402 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 403                                 struct kobj_attribute *a, char *buf)
 404 {
 405         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 406
 407         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 408 }
 409
 410 BTRFS_ATTR(nodesize, btrfs_nodesize_show);
 411
 412 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 413                                 struct kobj_attribute *a, char *buf)
 414 {
 415         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 416
 417         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 418 }
 419
 420 BTRFS_ATTR(sectorsize, btrfs_sectorsize_show);
 421
 422 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 423                                 struct kobj_attribute *a, char *buf)
 424 {
 425         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 426
 427         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 428 }
 429
 430 BTRFS_ATTR(clone_alignment, btrfs_clone_alignment_show);
 431
 432 static const struct attribute *btrfs_attrs[] = {
 433         BTRFS_ATTR_PTR(label),
 434         BTRFS_ATTR_PTR(nodesize),
 435         BTRFS_ATTR_PTR(sectorsize),
 436         BTRFS_ATTR_PTR(clone_alignment),
 437         NULL,
 438 };
 439
 440 static void btrfs_release_super_kobj(struct kobject *kobj)
 441 {
 442         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 443
 444         memset(&fs_devs->super_kobj, 0, sizeof(struct kobject));
 445         complete(&fs_devs->kobj_unregister);
 446 }
 447
 448 static struct kobj_type btrfs_ktype = {
 449         .sysfs_ops      = &kobj_sysfs_ops,
 450         .release        = btrfs_release_super_kobj,
 451 };
 452
 453 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 454 {
 455         if (kobj->ktype != &btrfs_ktype)
 456                 return NULL;
 457         return container_of(kobj, struct btrfs_fs_devices, super_kobj);
 458 }
 459
 460 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 461 {
 462         if (kobj->ktype != &btrfs_ktype)
 463                 return NULL;
 464         return to_fs_devs(kobj)->fs_info;
 465 }
 466
 467 #define NUM_FEATURE_BITS 64
 468 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 469 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 470
 471 static const u64 supported_feature_masks[3] = {
 472         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 473         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 474         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 475 };
 476
 477 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 478 {
 479         int set;
 480
 481         for (set = 0; set < FEAT_MAX; set++) {
 482                 int i;
 483                 struct attribute *attrs[2];
 484                 struct attribute_group agroup = {
 485                         .name = "features",
 486                         .attrs = attrs,
 487                 };
 488                 u64 features = get_features(fs_info, set);
 489                 features &= ~supported_feature_masks[set];
 490
 491                 if (!features)
 492                         continue;
 493
 494                 attrs[1] = NULL;
 495                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 496                         struct btrfs_feature_attr *fa;
 497
 498                         if (!(features & (1ULL << i)))
 499                                 continue;
 500
 501                         fa = &btrfs_feature_attrs[set][i];
 502                         attrs[0] = &fa->kobj_attr.attr;
 503                         if (add) {
 504                                 int ret;
 505                                 ret = sysfs_merge_group(&fs_info->fs_devices->super_kobj,
 506                                                         &agroup);
 507                                 if (ret)
 508                                         return ret;
 509                         } else
 510                                 sysfs_unmerge_group(&fs_info->fs_devices->super_kobj,
 511                                                     &agroup);
 512                 }
 513
 514         }
 515         return 0;
 516 }
 517
 518 static void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 519 {
 520         if (fs_devs->device_dir_kobj) {
 521                 kobject_del(fs_devs->device_dir_kobj);
 522                 kobject_put(fs_devs->device_dir_kobj);
 523                 fs_devs->device_dir_kobj = NULL;
 524         }
 525
 526         kobject_del(&fs_devs->super_kobj);
 527         kobject_put(&fs_devs->super_kobj);
 528         wait_for_completion(&fs_devs->kobj_unregister);
 529 }
 530
 531 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 532 {
 533         btrfs_reset_fs_info_ptr(fs_info);
 534
 535         if (fs_info->space_info_kobj) {
 536                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 537                 kobject_del(fs_info->space_info_kobj);
 538                 kobject_put(fs_info->space_info_kobj);
 539         }
 540         addrm_unknown_feature_attrs(fs_info, false);
 541         sysfs_remove_group(&fs_info->fs_devices->super_kobj, &btrfs_feature_attr_group);
 542         sysfs_remove_files(&fs_info->fs_devices->super_kobj, btrfs_attrs);
 543         btrfs_kobj_rm_device(fs_info, NULL);
 544         btrfs_sysfs_remove_fsid(fs_info->fs_devices);
 545 }
 546
 547 const char * const btrfs_feature_set_names[3] = {
 548         [FEAT_COMPAT]    = "compat",
 549         [FEAT_COMPAT_RO] = "compat_ro",
 550         [FEAT_INCOMPAT]  = "incompat",
 551 };
 552
 553 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 554 {
 555         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 556         int len = 0;
 557         int i;
 558         char *str;
 559
 560         str = kmalloc(bufsize, GFP_KERNEL);
 561         if (!str)
 562                 return str;
 563
 564         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 565                 const char *name;
 566
 567                 if (!(flags & (1ULL << i)))
 568                         continue;
 569
 570                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 571                 len += snprintf(str + len, bufsize - len, "%s%s",
 572                                 len ? "," : "", name);
 573         }
 574
 575         return str;
 576 }
 577
 578 static void init_feature_attrs(void)
 579 {
 580         struct btrfs_feature_attr *fa;
 581         int set, i;
 582
 583         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 584                      ARRAY_SIZE(btrfs_feature_attrs));
 585         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 586                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 587
 588         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 589         memset(btrfs_unknown_feature_names, 0,
 590                sizeof(btrfs_unknown_feature_names));
 591
 592         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 593                 struct btrfs_feature_attr *sfa;
 594                 struct attribute *a = btrfs_supported_feature_attrs[i];
 595                 int bit;
 596                 sfa = attr_to_btrfs_feature_attr(a);
 597                 bit = ilog2(sfa->feature_bit);
 598                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 599
 600                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 601         }
 602
 603         for (set = 0; set < FEAT_MAX; set++) {
 604                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 605                         char *name = btrfs_unknown_feature_names[set][i];
 606                         fa = &btrfs_feature_attrs[set][i];
 607
 608                         if (fa->kobj_attr.attr.name)
 609                                 continue;
 610
 611                         snprintf(name, 13, "%s:%u",
 612                                  btrfs_feature_set_names[set], i);
 613
 614                         fa->kobj_attr.attr.name = name;
 615                         fa->kobj_attr.attr.mode = S_IRUGO;
 616                         fa->feature_set = set;
 617                         fa->feature_bit = 1ULL << i;
 618                 }
 619         }
 620 }
 621
 622 /* when one_device is NULL, it removes all device links */
 623
 624 int btrfs_kobj_rm_device(struct btrfs_fs_info *fs_info,
 625                 struct btrfs_device *one_device)
 626 {
 627         struct hd_struct *disk;
 628         struct kobject *disk_kobj;
 629
 630         if (!fs_info->fs_devices->device_dir_kobj)
 631                 return -EINVAL;
 632
 633         if (one_device && one_device->bdev) {
 634                 disk = one_device->bdev->bd_part;
 635                 disk_kobj = &part_to_dev(disk)->kobj;
 636
 637                 sysfs_remove_link(fs_info->fs_devices->device_dir_kobj,
 638                                                 disk_kobj->name);
 639         }
 640
 641         if (one_device)
 642                 return 0;
 643
 644         list_for_each_entry(one_device,
 645                         &fs_info->fs_devices->devices, dev_list) {
 646                 if (!one_device->bdev)
 647                         continue;
 648                 disk = one_device->bdev->bd_part;
 649                 disk_kobj = &part_to_dev(disk)->kobj;
 650
 651                 sysfs_remove_link(fs_info->fs_devices->device_dir_kobj,
 652                                                 disk_kobj->name);
 653         }
 654
 655         return 0;
 656 }
 657
 658 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 659 {
 660         if (!fs_devs->device_dir_kobj)
 661                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 662                                                 &fs_devs->super_kobj);
 663
 664         if (!fs_devs->device_dir_kobj)
 665                 return -ENOMEM;
 666
 667         return 0;
 668 }
 669
 670 int btrfs_kobj_add_device(struct btrfs_fs_info *fs_info,
 671                 struct btrfs_device *one_device)
 672 {
 673         int error = 0;
 674         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 675         struct btrfs_device *dev;
 676
 677         error = btrfs_sysfs_add_device(fs_devices);
 678         if (error)
 679                 return error;
 680
 681         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 682                 struct hd_struct *disk;
 683                 struct kobject *disk_kobj;
 684
 685                 if (!dev->bdev)
 686                         continue;
 687
 688                 if (one_device && one_device != dev)
 689                         continue;
 690
 691                 disk = dev->bdev->bd_part;
 692                 disk_kobj = &part_to_dev(disk)->kobj;
 693
 694                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 695                                           disk_kobj, disk_kobj->name);
 696                 if (error)
 697                         break;
 698         }
 699
 700         return error;
 701 }
 702
 703 /* /sys/fs/btrfs/ entry */
 704 static struct kset *btrfs_kset;
 705
 706 /* /sys/kernel/debug/btrfs */
 707 static struct dentry *btrfs_debugfs_root_dentry;
 708
 709 /* Debugging tunables and exported data */
 710 u64 btrfs_debugfs_test;
 711
 712 /*
 713  * Can be called by the device discovery thread.
 714  * And parent can be specified for seed device
 715  */
 716 static int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 717                                 struct kobject *parent)
 718 {
 719         int error;
 720
 721         init_completion(&fs_devs->kobj_unregister);
 722         fs_devs->super_kobj.kset = btrfs_kset;
 723         error = kobject_init_and_add(&fs_devs->super_kobj, &btrfs_ktype, NULL,
 724                                      "%pU", fs_devs->fsid);
 725         return error;
 726 }
 727
 728 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 729 {
 730         int error;
 731         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 732         struct kobject *super_kobj = &fs_devs->super_kobj;
 733
 734         btrfs_set_fs_info_ptr(fs_info);
 735
 736         error = btrfs_sysfs_add_fsid(fs_devs, NULL);
 737         if (error)
 738                 return error;
 739
 740         error = btrfs_kobj_add_device(fs_info, NULL);
 741         if (error) {
 742                 btrfs_sysfs_remove_fsid(fs_devs);
 743                 return error;
 744         }
 745
 746         error = sysfs_create_files(super_kobj, btrfs_attrs);
 747         if (error) {
 748                 btrfs_sysfs_remove_fsid(fs_devs);
 749                 return error;
 750         }
 751
 752         error = sysfs_create_group(super_kobj,
 753                                    &btrfs_feature_attr_group);
 754         if (error)
 755                 goto failure;
 756
 757         error = addrm_unknown_feature_attrs(fs_info, true);
 758         if (error)
 759                 goto failure;
 760
 761         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 762                                                   super_kobj);
 763         if (!fs_info->space_info_kobj) {
 764                 error = -ENOMEM;
 765                 goto failure;
 766         }
 767
 768         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 769         if (error)
 770                 goto failure;
 771
 772         return 0;
 773 failure:
 774         btrfs_sysfs_remove_one(fs_info);
 775         return error;
 776 }
 777
 778 static int btrfs_init_debugfs(void)
 779 {
 780 #ifdef CONFIG_DEBUG_FS
 781         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 782         if (!btrfs_debugfs_root_dentry)
 783                 return -ENOMEM;
 784
 785         debugfs_create_u64("test", S_IRUGO | S_IWUGO, btrfs_debugfs_root_dentry,
 786                         &btrfs_debugfs_test);
 787 #endif
 788         return 0;
 789 }
 790
 791 int btrfs_init_sysfs(void)
 792 {
 793         int ret;
 794
 795         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 796         if (!btrfs_kset)
 797                 return -ENOMEM;
 798
 799         ret = btrfs_init_debugfs();
 800         if (ret)
 801                 goto out1;
 802
 803         init_feature_attrs();
 804         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 805         if (ret)
 806                 goto out2;
 807
 808         return 0;
 809 out2:
 810         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 811 out1:
 812         kset_unregister(btrfs_kset);
 813
 814         return ret;
 815 }
 816
 817 void btrfs_exit_sysfs(void)
 818 {
 819         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 820         kset_unregister(btrfs_kset);
 821         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 822 }
 823