linux/fs/btrfs/sysfs.c
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   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
  35static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  36
  37static u64 get_features(struct btrfs_fs_info *fs_info,
  38                        enum btrfs_feature_set set)
  39{
  40        struct btrfs_super_block *disk_super = fs_info->super_copy;
  41        if (set == FEAT_COMPAT)
  42                return btrfs_super_compat_flags(disk_super);
  43        else if (set == FEAT_COMPAT_RO)
  44                return btrfs_super_compat_ro_flags(disk_super);
  45        else
  46                return btrfs_super_incompat_flags(disk_super);
  47}
  48
  49static void set_features(struct btrfs_fs_info *fs_info,
  50                         enum btrfs_feature_set set, u64 features)
  51{
  52        struct btrfs_super_block *disk_super = fs_info->super_copy;
  53        if (set == FEAT_COMPAT)
  54                btrfs_set_super_compat_flags(disk_super, features);
  55        else if (set == FEAT_COMPAT_RO)
  56                btrfs_set_super_compat_ro_flags(disk_super, features);
  57        else
  58                btrfs_set_super_incompat_flags(disk_super, features);
  59}
  60
  61static int can_modify_feature(struct btrfs_feature_attr *fa)
  62{
  63        int val = 0;
  64        u64 set, clear;
  65        switch (fa->feature_set) {
  66        case FEAT_COMPAT:
  67                set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  68                clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  69                break;
  70        case FEAT_COMPAT_RO:
  71                set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  72                clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  73                break;
  74        case FEAT_INCOMPAT:
  75                set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  76                clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  77                break;
  78        default:
  79                printk(KERN_WARNING "btrfs: sysfs: unknown feature set %d\n",
  80                                fa->feature_set);
  81                return 0;
  82        }
  83
  84        if (set & fa->feature_bit)
  85                val |= 1;
  86        if (clear & fa->feature_bit)
  87                val |= 2;
  88
  89        return val;
  90}
  91
  92static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  93                                       struct kobj_attribute *a, char *buf)
  94{
  95        int val = 0;
  96        struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  97        struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  98        if (fs_info) {
  99                u64 features = get_features(fs_info, fa->feature_set);
 100                if (features & fa->feature_bit)
 101                        val = 1;
 102        } else
 103                val = can_modify_feature(fa);
 104
 105        return snprintf(buf, PAGE_SIZE, "%d\n", val);
 106}
 107
 108static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 109                                        struct kobj_attribute *a,
 110                                        const char *buf, size_t count)
 111{
 112        struct btrfs_fs_info *fs_info;
 113        struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 114        struct btrfs_trans_handle *trans;
 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        trans = btrfs_start_transaction(fs_info->fs_root, 0);
 157        if (IS_ERR(trans))
 158                return PTR_ERR(trans);
 159
 160        spin_lock(&fs_info->super_lock);
 161        features = get_features(fs_info, fa->feature_set);
 162        if (val)
 163                features |= fa->feature_bit;
 164        else
 165                features &= ~fa->feature_bit;
 166        set_features(fs_info, fa->feature_set, features);
 167        spin_unlock(&fs_info->super_lock);
 168
 169        ret = btrfs_commit_transaction(trans, fs_info->fs_root);
 170        if (ret)
 171                return ret;
 172
 173        return count;
 174}
 175
 176static umode_t btrfs_feature_visible(struct kobject *kobj,
 177                                     struct attribute *attr, int unused)
 178{
 179        struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 180        umode_t mode = attr->mode;
 181
 182        if (fs_info) {
 183                struct btrfs_feature_attr *fa;
 184                u64 features;
 185
 186                fa = attr_to_btrfs_feature_attr(attr);
 187                features = get_features(fs_info, fa->feature_set);
 188
 189                if (can_modify_feature(fa))
 190                        mode |= S_IWUSR;
 191                else if (!(features & fa->feature_bit))
 192                        mode = 0;
 193        }
 194
 195        return mode;
 196}
 197
 198BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 199BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 200BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 201BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 202BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 203BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 204BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 205BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 206BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 207
 208static struct attribute *btrfs_supported_feature_attrs[] = {
 209        BTRFS_FEAT_ATTR_PTR(mixed_backref),
 210        BTRFS_FEAT_ATTR_PTR(default_subvol),
 211        BTRFS_FEAT_ATTR_PTR(mixed_groups),
 212        BTRFS_FEAT_ATTR_PTR(compress_lzo),
 213        BTRFS_FEAT_ATTR_PTR(big_metadata),
 214        BTRFS_FEAT_ATTR_PTR(extended_iref),
 215        BTRFS_FEAT_ATTR_PTR(raid56),
 216        BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 217        BTRFS_FEAT_ATTR_PTR(no_holes),
 218        NULL
 219};
 220
 221static 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
 227static 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
 238static 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}
 245BTRFS_ATTR(global_rsv_size, 0444, global_rsv_size_show);
 246
 247static 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}
 254BTRFS_ATTR(global_rsv_reserved, 0444, 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
 259static ssize_t raid_bytes_show(struct kobject *kobj,
 260                               struct kobj_attribute *attr, char *buf);
 261BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
 262BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
 263
 264static 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
 284static struct attribute *raid_attributes[] = {
 285        BTRFS_RAID_ATTR_PTR(total_bytes),
 286        BTRFS_RAID_ATTR_PTR(used_bytes),
 287        NULL
 288};
 289
 290static void release_raid_kobj(struct kobject *kobj)
 291{
 292        kfree(to_raid_kobj(kobj));
 293}
 294
 295struct 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)                                          \
 302static 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}                                                                       \
 309BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
 310
 311static 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
 320SPACE_INFO_ATTR(flags);
 321SPACE_INFO_ATTR(total_bytes);
 322SPACE_INFO_ATTR(bytes_used);
 323SPACE_INFO_ATTR(bytes_pinned);
 324SPACE_INFO_ATTR(bytes_reserved);
 325SPACE_INFO_ATTR(bytes_may_use);
 326SPACE_INFO_ATTR(disk_used);
 327SPACE_INFO_ATTR(disk_total);
 328BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
 329
 330static 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
 343static 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
 350struct kobj_type space_info_ktype = {
 351        .sysfs_ops = &kobj_sysfs_ops,
 352        .release = space_info_release,
 353        .default_attrs = space_info_attrs,
 354};
 355
 356static const struct attribute *allocation_attrs[] = {
 357        BTRFS_ATTR_PTR(global_rsv_reserved),
 358        BTRFS_ATTR_PTR(global_rsv_size),
 359        NULL,
 360};
 361
 362static 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        return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
 367}
 368
 369static ssize_t btrfs_label_store(struct kobject *kobj,
 370                                 struct kobj_attribute *a,
 371                                 const char *buf, size_t len)
 372{
 373        struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 374        struct btrfs_trans_handle *trans;
 375        struct btrfs_root *root = fs_info->fs_root;
 376        int ret;
 377
 378        if (len >= BTRFS_LABEL_SIZE)
 379                return -EINVAL;
 380
 381        trans = btrfs_start_transaction(root, 0);
 382        if (IS_ERR(trans))
 383                return PTR_ERR(trans);
 384
 385        spin_lock(&root->fs_info->super_lock);
 386        strcpy(fs_info->super_copy->label, buf);
 387        spin_unlock(&root->fs_info->super_lock);
 388        ret = btrfs_commit_transaction(trans, root);
 389
 390        if (!ret)
 391                return len;
 392
 393        return ret;
 394}
 395BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
 396
 397static ssize_t btrfs_no_store(struct kobject *kobj,
 398                                 struct kobj_attribute *a,
 399                                 const char *buf, size_t len)
 400{
 401        return -EPERM;
 402}
 403
 404static 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
 412BTRFS_ATTR_RW(nodesize, 0444, btrfs_nodesize_show, btrfs_no_store);
 413
 414static 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
 422BTRFS_ATTR_RW(sectorsize, 0444, btrfs_sectorsize_show, btrfs_no_store);
 423
 424static 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
 432BTRFS_ATTR_RW(clone_alignment, 0444, btrfs_clone_alignment_show, btrfs_no_store);
 433
 434static 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
 442static void btrfs_release_super_kobj(struct kobject *kobj)
 443{
 444        struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 445        complete(&fs_info->kobj_unregister);
 446}
 447
 448static struct kobj_type btrfs_ktype = {
 449        .sysfs_ops      = &kobj_sysfs_ops,
 450        .release        = btrfs_release_super_kobj,
 451        .default_attrs  = btrfs_attrs,
 452};
 453
 454static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 455{
 456        if (kobj->ktype != &btrfs_ktype)
 457                return NULL;
 458        return container_of(kobj, struct btrfs_fs_info, super_kobj);
 459}
 460
 461#define NUM_FEATURE_BITS 64
 462static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 463static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 464
 465static u64 supported_feature_masks[3] = {
 466        [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 467        [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 468        [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 469};
 470
 471static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 472{
 473        int set;
 474
 475        for (set = 0; set < FEAT_MAX; set++) {
 476                int i;
 477                struct attribute *attrs[2];
 478                struct attribute_group agroup = {
 479                        .name = "features",
 480                        .attrs = attrs,
 481                };
 482                u64 features = get_features(fs_info, set);
 483                features &= ~supported_feature_masks[set];
 484
 485                if (!features)
 486                        continue;
 487
 488                attrs[1] = NULL;
 489                for (i = 0; i < NUM_FEATURE_BITS; i++) {
 490                        struct btrfs_feature_attr *fa;
 491
 492                        if (!(features & (1ULL << i)))
 493                                continue;
 494
 495                        fa = &btrfs_feature_attrs[set][i];
 496                        attrs[0] = &fa->kobj_attr.attr;
 497                        if (add) {
 498                                int ret;
 499                                ret = sysfs_merge_group(&fs_info->super_kobj,
 500                                                        &agroup);
 501                                if (ret)
 502                                        return ret;
 503                        } else
 504                                sysfs_unmerge_group(&fs_info->super_kobj,
 505                                                    &agroup);
 506                }
 507
 508        }
 509        return 0;
 510}
 511
 512static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 513{
 514        kobject_del(&fs_info->super_kobj);
 515        kobject_put(&fs_info->super_kobj);
 516        wait_for_completion(&fs_info->kobj_unregister);
 517}
 518
 519void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 520{
 521        if (fs_info->space_info_kobj) {
 522                sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 523                kobject_del(fs_info->space_info_kobj);
 524                kobject_put(fs_info->space_info_kobj);
 525        }
 526        kobject_del(fs_info->device_dir_kobj);
 527        kobject_put(fs_info->device_dir_kobj);
 528        addrm_unknown_feature_attrs(fs_info, false);
 529        sysfs_remove_group(&fs_info->super_kobj, &btrfs_feature_attr_group);
 530        __btrfs_sysfs_remove_one(fs_info);
 531}
 532
 533const char * const btrfs_feature_set_names[3] = {
 534        [FEAT_COMPAT]    = "compat",
 535        [FEAT_COMPAT_RO] = "compat_ro",
 536        [FEAT_INCOMPAT]  = "incompat",
 537};
 538
 539char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 540{
 541        size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 542        int len = 0;
 543        int i;
 544        char *str;
 545
 546        str = kmalloc(bufsize, GFP_KERNEL);
 547        if (!str)
 548                return str;
 549
 550        for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 551                const char *name;
 552
 553                if (!(flags & (1ULL << i)))
 554                        continue;
 555
 556                name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 557                len += snprintf(str + len, bufsize - len, "%s%s",
 558                                len ? "," : "", name);
 559        }
 560
 561        return str;
 562}
 563
 564static void init_feature_attrs(void)
 565{
 566        struct btrfs_feature_attr *fa;
 567        int set, i;
 568
 569        BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 570                     ARRAY_SIZE(btrfs_feature_attrs));
 571        BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 572                     ARRAY_SIZE(btrfs_feature_attrs[0]));
 573
 574        memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 575        memset(btrfs_unknown_feature_names, 0,
 576               sizeof(btrfs_unknown_feature_names));
 577
 578        for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 579                struct btrfs_feature_attr *sfa;
 580                struct attribute *a = btrfs_supported_feature_attrs[i];
 581                int bit;
 582                sfa = attr_to_btrfs_feature_attr(a);
 583                bit = ilog2(sfa->feature_bit);
 584                fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 585
 586                fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 587        }
 588
 589        for (set = 0; set < FEAT_MAX; set++) {
 590                for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 591                        char *name = btrfs_unknown_feature_names[set][i];
 592                        fa = &btrfs_feature_attrs[set][i];
 593
 594                        if (fa->kobj_attr.attr.name)
 595                                continue;
 596
 597                        snprintf(name, 13, "%s:%u",
 598                                 btrfs_feature_set_names[set], i);
 599
 600                        fa->kobj_attr.attr.name = name;
 601                        fa->kobj_attr.attr.mode = S_IRUGO;
 602                        fa->feature_set = set;
 603                        fa->feature_bit = 1ULL << i;
 604                }
 605        }
 606}
 607
 608int btrfs_kobj_rm_device(struct btrfs_fs_info *fs_info,
 609                struct btrfs_device *one_device)
 610{
 611        struct hd_struct *disk;
 612        struct kobject *disk_kobj;
 613
 614        if (!fs_info->device_dir_kobj)
 615                return -EINVAL;
 616
 617        if (one_device && one_device->bdev) {
 618                disk = one_device->bdev->bd_part;
 619                disk_kobj = &part_to_dev(disk)->kobj;
 620
 621                sysfs_remove_link(fs_info->device_dir_kobj,
 622                                                disk_kobj->name);
 623        }
 624
 625        return 0;
 626}
 627
 628int btrfs_kobj_add_device(struct btrfs_fs_info *fs_info,
 629                struct btrfs_device *one_device)
 630{
 631        int error = 0;
 632        struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 633        struct btrfs_device *dev;
 634
 635        if (!fs_info->device_dir_kobj)
 636                fs_info->device_dir_kobj = kobject_create_and_add("devices",
 637                                                &fs_info->super_kobj);
 638
 639        if (!fs_info->device_dir_kobj)
 640                return -ENOMEM;
 641
 642        list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 643                struct hd_struct *disk;
 644                struct kobject *disk_kobj;
 645
 646                if (!dev->bdev)
 647                        continue;
 648
 649                if (one_device && one_device != dev)
 650                        continue;
 651
 652                disk = dev->bdev->bd_part;
 653                disk_kobj = &part_to_dev(disk)->kobj;
 654
 655                error = sysfs_create_link(fs_info->device_dir_kobj,
 656                                          disk_kobj, disk_kobj->name);
 657                if (error)
 658                        break;
 659        }
 660
 661        return error;
 662}
 663
 664/* /sys/fs/btrfs/ entry */
 665static struct kset *btrfs_kset;
 666
 667/* /sys/kernel/debug/btrfs */
 668static struct dentry *btrfs_debugfs_root_dentry;
 669
 670/* Debugging tunables and exported data */
 671u64 btrfs_debugfs_test;
 672
 673int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 674{
 675        int error;
 676
 677        init_completion(&fs_info->kobj_unregister);
 678        fs_info->super_kobj.kset = btrfs_kset;
 679        error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 680                                     "%pU", fs_info->fsid);
 681        if (error)
 682                return error;
 683
 684        error = sysfs_create_group(&fs_info->super_kobj,
 685                                   &btrfs_feature_attr_group);
 686        if (error) {
 687                __btrfs_sysfs_remove_one(fs_info);
 688                return error;
 689        }
 690
 691        error = addrm_unknown_feature_attrs(fs_info, true);
 692        if (error)
 693                goto failure;
 694
 695        error = btrfs_kobj_add_device(fs_info, NULL);
 696        if (error)
 697                goto failure;
 698
 699        fs_info->space_info_kobj = kobject_create_and_add("allocation",
 700                                                  &fs_info->super_kobj);
 701        if (!fs_info->space_info_kobj) {
 702                error = -ENOMEM;
 703                goto failure;
 704        }
 705
 706        error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 707        if (error)
 708                goto failure;
 709
 710        return 0;
 711failure:
 712        btrfs_sysfs_remove_one(fs_info);
 713        return error;
 714}
 715
 716static int btrfs_init_debugfs(void)
 717{
 718#ifdef CONFIG_DEBUG_FS
 719        btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 720        if (!btrfs_debugfs_root_dentry)
 721                return -ENOMEM;
 722
 723        debugfs_create_u64("test", S_IRUGO | S_IWUGO, btrfs_debugfs_root_dentry,
 724                        &btrfs_debugfs_test);
 725#endif
 726        return 0;
 727}
 728
 729int btrfs_init_sysfs(void)
 730{
 731        int ret;
 732
 733        btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 734        if (!btrfs_kset)
 735                return -ENOMEM;
 736
 737        ret = btrfs_init_debugfs();
 738        if (ret)
 739                return ret;
 740
 741        init_feature_attrs();
 742        ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 743
 744        return ret;
 745}
 746
 747void btrfs_exit_sysfs(void)
 748{
 749        sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 750        kset_unregister(btrfs_kset);
 751        debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 752}
 753
 754