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