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);
  36static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  37
  38static 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
  50static 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
  62static 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
  93static 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
 109static 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
 174static 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
 196BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 197BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 198BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 199BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 200BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 201BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 202BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 203BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 204BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 205BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 206
 207static 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
 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, 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, 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, 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, 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        char *label = fs_info->super_copy->label;
 367        return snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 368}
 369
 370static 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}
 402BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
 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(nodesize, btrfs_nodesize_show);
 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(sectorsize, btrfs_sectorsize_show);
 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(clone_alignment, btrfs_clone_alignment_show);
 433
 434static 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
 442static 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
 450static struct kobj_type btrfs_ktype = {
 451        .sysfs_ops      = &kobj_sysfs_ops,
 452        .release        = btrfs_release_fsid_kobj,
 453};
 454
 455static 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
 462static 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
 470static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 471static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 472
 473static 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
 479static 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
 520static 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 */
 536void 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
 550void 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
 565const char * const btrfs_feature_set_names[3] = {
 566        [FEAT_COMPAT]    = "compat",
 567        [FEAT_COMPAT_RO] = "compat_ro",
 568        [FEAT_INCOMPAT]  = "incompat",
 569};
 570
 571char *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
 596static 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
 642int 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
 676int 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
 688int 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 */
 717static struct kset *btrfs_kset;
 718
 719/* /sys/kernel/debug/btrfs */
 720static struct dentry *btrfs_debugfs_root_dentry;
 721
 722/* Debugging tunables and exported data */
 723u64 btrfs_debugfs_test;
 724
 725/*
 726 * Can be called by the device discovery thread.
 727 * And parent can be specified for seed device
 728 */
 729int 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
 741int 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;
 780failure:
 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 */
 790void 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
 818static 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
 831int 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;
 849out2:
 850        debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 851out1:
 852        kset_unregister(btrfs_kset);
 853
 854        return ret;
 855}
 856
 857void 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
 864