// SPDX-License-Identifier: GPL-2.0

  /*
   * Copyright (C) 2007 Oracle.  All rights reserved.

   */

  #include <linux/sched.h>

  #include <linux/sched/mm.h>

  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/completion.h>

  #include <linux/bug.h>

  #include <crypto/hash.h>

  #include "ctree.h"

  #include "discard.h"

  #include "disk-io.h"

  #include "send.h"

  #include "transaction.h"

  #include "sysfs.h"

  #include "volumes.h"

  #include "space-info.h"

  #include "block-group.h"

  #include "qgroup.h"

  struct btrfs_feature_attr {
  	struct kobj_attribute kobj_attr;
  	enum btrfs_feature_set feature_set;
  	u64 feature_bit;
  };
  
  /* For raid type sysfs entries */
  struct raid_kobject {
  	u64 flags;
  	struct kobject kobj;
  };
  
  #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)			\
  {									\
  	.attr	= { .name = __stringify(_name), .mode = _mode },	\
  	.show	= _show,						\
  	.store	= _store,						\
  }
  
  #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)			\
  	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
  			__INIT_KOBJ_ATTR(_name, 0644, _show, _store)
  
  #define BTRFS_ATTR(_prefix, _name, _show)				\
  	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
  			__INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
  
  #define BTRFS_ATTR_PTR(_prefix, _name)					\
  	(&btrfs_attr_##_prefix##_##_name.attr)
  
  #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
  static struct btrfs_feature_attr btrfs_attr_features_##_name = {	     \
  	.kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,			     \
  				      btrfs_feature_attr_show,		     \
  				      btrfs_feature_attr_store),	     \
  	.feature_set	= _feature_set,					     \
  	.feature_bit	= _feature_prefix ##_## _feature_bit,		     \
  }
  #define BTRFS_FEAT_ATTR_PTR(_name)					     \
  	(&btrfs_attr_features_##_name.kobj_attr.attr)
  
  #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
  	BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
  #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
  	BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
  #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
  	BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)

  static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);

  static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);

  static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
  {
  	return container_of(a, struct btrfs_feature_attr, kobj_attr);
  }
  
  static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
  {
  	return container_of(attr, struct kobj_attribute, attr);
  }
  
  static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
  		struct attribute *attr)
  {
  	return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
  }

  static u64 get_features(struct btrfs_fs_info *fs_info,
  			enum btrfs_feature_set set)

  {

  	struct btrfs_super_block *disk_super = fs_info->super_copy;
  	if (set == FEAT_COMPAT)
  		return btrfs_super_compat_flags(disk_super);
  	else if (set == FEAT_COMPAT_RO)
  		return btrfs_super_compat_ro_flags(disk_super);
  	else
  		return btrfs_super_incompat_flags(disk_super);

  }

  static void set_features(struct btrfs_fs_info *fs_info,
  			 enum btrfs_feature_set set, u64 features)
  {
  	struct btrfs_super_block *disk_super = fs_info->super_copy;
  	if (set == FEAT_COMPAT)
  		btrfs_set_super_compat_flags(disk_super, features);
  	else if (set == FEAT_COMPAT_RO)
  		btrfs_set_super_compat_ro_flags(disk_super, features);
  	else
  		btrfs_set_super_incompat_flags(disk_super, features);
  }
  
  static int can_modify_feature(struct btrfs_feature_attr *fa)
  {
  	int val = 0;
  	u64 set, clear;
  	switch (fa->feature_set) {
  	case FEAT_COMPAT:
  		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  		break;
  	case FEAT_COMPAT_RO:
  		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  		break;
  	case FEAT_INCOMPAT:
  		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  		break;
  	default:

  		pr_warn("btrfs: sysfs: unknown feature set %d
  ",

  				fa->feature_set);
  		return 0;

  	}
  
  	if (set & fa->feature_bit)
  		val |= 1;
  	if (clear & fa->feature_bit)
  		val |= 2;
  
  	return val;
  }

  static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  				       struct kobj_attribute *a, char *buf)

  {

  	int val = 0;

  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

  	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);

  	if (fs_info) {

  		u64 features = get_features(fs_info, fa->feature_set);
  		if (features & fa->feature_bit)
  			val = 1;

  	} else
  		val = can_modify_feature(fa);

  	return scnprintf(buf, PAGE_SIZE, "%d
  ", val);

  }

  static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
  					struct kobj_attribute *a,
  					const char *buf, size_t count)
  {
  	struct btrfs_fs_info *fs_info;
  	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);

  	u64 features, set, clear;
  	unsigned long val;
  	int ret;
  
  	fs_info = to_fs_info(kobj);
  	if (!fs_info)
  		return -EPERM;

  	if (sb_rdonly(fs_info->sb))

  		return -EROFS;

  	ret = kstrtoul(skip_spaces(buf), 0, &val);
  	if (ret)
  		return ret;
  
  	if (fa->feature_set == FEAT_COMPAT) {
  		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  	} else if (fa->feature_set == FEAT_COMPAT_RO) {
  		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  	} else {
  		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  	}
  
  	features = get_features(fs_info, fa->feature_set);
  
  	/* Nothing to do */
  	if ((val && (features & fa->feature_bit)) ||
  	    (!val && !(features & fa->feature_bit)))
  		return count;
  
  	if ((val && !(set & fa->feature_bit)) ||
  	    (!val && !(clear & fa->feature_bit))) {
  		btrfs_info(fs_info,
  			"%sabling feature %s on mounted fs is not supported.",
  			val ? "En" : "Dis", fa->kobj_attr.attr.name);
  		return -EPERM;
  	}
  
  	btrfs_info(fs_info, "%s %s feature flag",
  		   val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);

  	spin_lock(&fs_info->super_lock);
  	features = get_features(fs_info, fa->feature_set);
  	if (val)
  		features |= fa->feature_bit;
  	else
  		features &= ~fa->feature_bit;
  	set_features(fs_info, fa->feature_set, features);
  	spin_unlock(&fs_info->super_lock);

  	/*
  	 * We don't want to do full transaction commit from inside sysfs
  	 */
  	btrfs_set_pending(fs_info, COMMIT);
  	wake_up_process(fs_info->transaction_kthread);

  
  	return count;
  }

  static umode_t btrfs_feature_visible(struct kobject *kobj,
  				     struct attribute *attr, int unused)

  {

  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  	umode_t mode = attr->mode;
  
  	if (fs_info) {
  		struct btrfs_feature_attr *fa;
  		u64 features;
  
  		fa = attr_to_btrfs_feature_attr(attr);
  		features = get_features(fs_info, fa->feature_set);

  		if (can_modify_feature(fa))
  			mode |= S_IWUSR;
  		else if (!(features & fa->feature_bit))

  			mode = 0;
  	}
  
  	return mode;

  }
  
  BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
  BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
  BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
  BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);

  BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);

  BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
  BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
  BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
  BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);

  BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);

  BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);

  BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);

  BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);

  
  static struct attribute *btrfs_supported_feature_attrs[] = {
  	BTRFS_FEAT_ATTR_PTR(mixed_backref),
  	BTRFS_FEAT_ATTR_PTR(default_subvol),
  	BTRFS_FEAT_ATTR_PTR(mixed_groups),
  	BTRFS_FEAT_ATTR_PTR(compress_lzo),

  	BTRFS_FEAT_ATTR_PTR(compress_zstd),

  	BTRFS_FEAT_ATTR_PTR(big_metadata),
  	BTRFS_FEAT_ATTR_PTR(extended_iref),
  	BTRFS_FEAT_ATTR_PTR(raid56),
  	BTRFS_FEAT_ATTR_PTR(skinny_metadata),

  	BTRFS_FEAT_ATTR_PTR(no_holes),

  	BTRFS_FEAT_ATTR_PTR(metadata_uuid),

  	BTRFS_FEAT_ATTR_PTR(free_space_tree),

  	BTRFS_FEAT_ATTR_PTR(raid1c34),

  	NULL
  };

  /*
   * Features which depend on feature bits and may differ between each fs.
   *
   * /sys/fs/btrfs/features lists all available features of this kernel while
   * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
   * can be changed online.
   */

  static const struct attribute_group btrfs_feature_attr_group = {
  	.name = "features",

  	.is_visible = btrfs_feature_visible,

  	.attrs = btrfs_supported_feature_attrs,
  };

  static ssize_t rmdir_subvol_show(struct kobject *kobj,
  				 struct kobj_attribute *ka, char *buf)
  {

  	return scnprintf(buf, PAGE_SIZE, "0
  ");

  }
  BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);

  static ssize_t supported_checksums_show(struct kobject *kobj,
  					struct kobj_attribute *a, char *buf)
  {
  	ssize_t ret = 0;
  	int i;
  
  	for (i = 0; i < btrfs_get_num_csums(); i++) {
  		/*
  		 * This "trick" only works as long as 'enum btrfs_csum_type' has
  		 * no holes in it
  		 */

  		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",

  				(i == 0 ? "" : " "), btrfs_super_csum_name(i));
  
  	}

  	ret += scnprintf(buf + ret, PAGE_SIZE - ret, "
  ");

  	return ret;
  }
  BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);

  static ssize_t send_stream_version_show(struct kobject *kobj,
  					struct kobj_attribute *ka, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%d
  ", BTRFS_SEND_STREAM_VERSION);
  }
  BTRFS_ATTR(static_feature, send_stream_version, send_stream_version_show);

  static struct attribute *btrfs_supported_static_feature_attrs[] = {
  	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),

  	BTRFS_ATTR_PTR(static_feature, supported_checksums),

  	BTRFS_ATTR_PTR(static_feature, send_stream_version),

  	NULL
  };
  
  /*
   * Features which only depend on kernel version.
   *
   * These are listed in /sys/fs/btrfs/features along with
   * btrfs_feature_attr_group
   */
  static const struct attribute_group btrfs_static_feature_attr_group = {
  	.name = "features",
  	.attrs = btrfs_supported_static_feature_attrs,
  };

  #ifdef CONFIG_BTRFS_DEBUG
  
  /*

   * Discard statistics and tunables
   */

  #define discard_to_fs_info(_kobj)	to_fs_info((_kobj)->parent->parent)

  static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
  					    struct kobj_attribute *a,
  					    char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%lld
  ",

  			atomic64_read(&fs_info->discard_ctl.discardable_bytes));
  }
  BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);

  static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
  					      struct kobj_attribute *a,
  					      char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%d
  ",

  			atomic_read(&fs_info->discard_ctl.discardable_extents));
  }
  BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);

  static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
  					       struct kobj_attribute *a,
  					       char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%lld
  ",

  			fs_info->discard_ctl.discard_bitmap_bytes);
  }
  BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
  
  static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
  					      struct kobj_attribute *a,
  					      char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%lld
  ",

  		atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
  }
  BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
  
  static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
  					       struct kobj_attribute *a,
  					       char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%lld
  ",

  			fs_info->discard_ctl.discard_extent_bytes);
  }
  BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);

  static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
  					     struct kobj_attribute *a,
  					     char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%u
  ",

  			READ_ONCE(fs_info->discard_ctl.iops_limit));
  }
  
  static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
  					      struct kobj_attribute *a,
  					      const char *buf, size_t len)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
  	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
  	u32 iops_limit;
  	int ret;
  
  	ret = kstrtou32(buf, 10, &iops_limit);
  	if (ret)
  		return -EINVAL;
  
  	WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
  
  	return len;
  }
  BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
  	      btrfs_discard_iops_limit_store);

  static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
  					     struct kobj_attribute *a,
  					     char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%u
  ",

  			READ_ONCE(fs_info->discard_ctl.kbps_limit));
  }
  
  static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
  					      struct kobj_attribute *a,
  					      const char *buf, size_t len)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
  	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
  	u32 kbps_limit;
  	int ret;
  
  	ret = kstrtou32(buf, 10, &kbps_limit);
  	if (ret)
  		return -EINVAL;
  
  	WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
  
  	return len;
  }
  BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
  	      btrfs_discard_kbps_limit_store);

  static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
  						   struct kobj_attribute *a,
  						   char *buf)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%llu
  ",

  			READ_ONCE(fs_info->discard_ctl.max_discard_size));
  }
  
  static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
  						    struct kobj_attribute *a,
  						    const char *buf, size_t len)
  {
  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
  	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
  	u64 max_discard_size;
  	int ret;
  
  	ret = kstrtou64(buf, 10, &max_discard_size);
  	if (ret)
  		return -EINVAL;
  
  	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
  
  	return len;
  }
  BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
  	      btrfs_discard_max_discard_size_store);

  static const struct attribute *discard_debug_attrs[] = {

  	BTRFS_ATTR_PTR(discard, discardable_bytes),

  	BTRFS_ATTR_PTR(discard, discardable_extents),

  	BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
  	BTRFS_ATTR_PTR(discard, discard_bytes_saved),
  	BTRFS_ATTR_PTR(discard, discard_extent_bytes),

  	BTRFS_ATTR_PTR(discard, iops_limit),

  	BTRFS_ATTR_PTR(discard, kbps_limit),

  	BTRFS_ATTR_PTR(discard, max_discard_size),

  	NULL,
  };
  
  /*

   * Runtime debugging exported via sysfs
   *
   * /sys/fs/btrfs/debug - applies to module or all filesystems
   * /sys/fs/btrfs/UUID  - applies only to the given filesystem
   */

  static const struct attribute *btrfs_debug_mount_attrs[] = {
  	NULL,
  };

  static struct attribute *btrfs_debug_feature_attrs[] = {
  	NULL
  };
  
  static const struct attribute_group btrfs_debug_feature_attr_group = {
  	.name = "debug",
  	.attrs = btrfs_debug_feature_attrs,
  };
  
  #endif

  static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
  {
  	u64 val;
  	if (lock)
  		spin_lock(lock);
  	val = *value_ptr;
  	if (lock)
  		spin_unlock(lock);

  	return scnprintf(buf, PAGE_SIZE, "%llu
  ", val);

  }
  
  static ssize_t global_rsv_size_show(struct kobject *kobj,
  				    struct kobj_attribute *ka, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
  	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
  	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
  }

  BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);

  
  static ssize_t global_rsv_reserved_show(struct kobject *kobj,
  					struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
  	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
  	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
  }

  BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);

  
  #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)

  #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)

  
  static ssize_t raid_bytes_show(struct kobject *kobj,
  			       struct kobj_attribute *attr, char *buf);

  BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
  BTRFS_ATTR(raid, used_bytes, raid_bytes_show);

  
  static ssize_t raid_bytes_show(struct kobject *kobj,
  			       struct kobj_attribute *attr, char *buf)
  
  {
  	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);

  	struct btrfs_block_group *block_group;

  	int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);

  	u64 val = 0;
  
  	down_read(&sinfo->groups_sem);
  	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {

  		if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))

  			val += block_group->length;

  		else

  			val += block_group->used;

  	}
  	up_read(&sinfo->groups_sem);

  	return scnprintf(buf, PAGE_SIZE, "%llu
  ", val);

  }

  static struct attribute *raid_attrs[] = {

  	BTRFS_ATTR_PTR(raid, total_bytes),
  	BTRFS_ATTR_PTR(raid, used_bytes),

  	NULL
  };

  ATTRIBUTE_GROUPS(raid);

  
  static void release_raid_kobj(struct kobject *kobj)
  {

  	kfree(to_raid_kobj(kobj));

  }

  static struct kobj_type btrfs_raid_ktype = {

  	.sysfs_ops = &kobj_sysfs_ops,
  	.release = release_raid_kobj,

  	.default_groups = raid_groups,

  };
  
  #define SPACE_INFO_ATTR(field)						\
  static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
  					     struct kobj_attribute *a,	\
  					     char *buf)			\
  {									\
  	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
  	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
  }									\

  BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)

  
  static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
  						       struct kobj_attribute *a,
  						       char *buf)
  {
  	struct btrfs_space_info *sinfo = to_space_info(kobj);
  	s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);

  	return scnprintf(buf, PAGE_SIZE, "%lld
  ", val);

  }
  
  SPACE_INFO_ATTR(flags);
  SPACE_INFO_ATTR(total_bytes);
  SPACE_INFO_ATTR(bytes_used);
  SPACE_INFO_ATTR(bytes_pinned);
  SPACE_INFO_ATTR(bytes_reserved);
  SPACE_INFO_ATTR(bytes_may_use);

  SPACE_INFO_ATTR(bytes_readonly);

  SPACE_INFO_ATTR(disk_used);
  SPACE_INFO_ATTR(disk_total);

  BTRFS_ATTR(space_info, total_bytes_pinned,
  	   btrfs_space_info_show_total_bytes_pinned);

  
  static struct attribute *space_info_attrs[] = {

  	BTRFS_ATTR_PTR(space_info, flags),
  	BTRFS_ATTR_PTR(space_info, total_bytes),
  	BTRFS_ATTR_PTR(space_info, bytes_used),
  	BTRFS_ATTR_PTR(space_info, bytes_pinned),
  	BTRFS_ATTR_PTR(space_info, bytes_reserved),
  	BTRFS_ATTR_PTR(space_info, bytes_may_use),
  	BTRFS_ATTR_PTR(space_info, bytes_readonly),
  	BTRFS_ATTR_PTR(space_info, disk_used),
  	BTRFS_ATTR_PTR(space_info, disk_total),
  	BTRFS_ATTR_PTR(space_info, total_bytes_pinned),

  	NULL,
  };

  ATTRIBUTE_GROUPS(space_info);

  
  static void space_info_release(struct kobject *kobj)
  {
  	struct btrfs_space_info *sinfo = to_space_info(kobj);
  	percpu_counter_destroy(&sinfo->total_bytes_pinned);
  	kfree(sinfo);
  }

  static struct kobj_type space_info_ktype = {

  	.sysfs_ops = &kobj_sysfs_ops,
  	.release = space_info_release,

  	.default_groups = space_info_groups,

  };
  
  static const struct attribute *allocation_attrs[] = {

  	BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
  	BTRFS_ATTR_PTR(allocation, global_rsv_size),

  	NULL,
  };

  static ssize_t btrfs_label_show(struct kobject *kobj,
  				struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

  	char *label = fs_info->super_copy->label;

  	ssize_t ret;
  
  	spin_lock(&fs_info->super_lock);

  	ret = scnprintf(buf, PAGE_SIZE, label[0] ? "%s
  " : "%s", label);

  	spin_unlock(&fs_info->super_lock);
  
  	return ret;

  }
  
  static ssize_t btrfs_label_store(struct kobject *kobj,
  				 struct kobj_attribute *a,
  				 const char *buf, size_t len)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

  	size_t p_len;

  	if (!fs_info)
  		return -EPERM;

  	if (sb_rdonly(fs_info->sb))

  		return -EROFS;

  	/*
  	 * p_len is the len until the first occurrence of either
  	 * '
  ' or '\0'
  	 */
  	p_len = strcspn(buf, "
  ");
  
  	if (p_len >= BTRFS_LABEL_SIZE)

  		return -EINVAL;

  	spin_lock(&fs_info->super_lock);

  	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
  	memcpy(fs_info->super_copy->label, buf, p_len);

  	spin_unlock(&fs_info->super_lock);

  	/*
  	 * We don't want to do full transaction commit from inside sysfs
  	 */
  	btrfs_set_pending(fs_info, COMMIT);
  	wake_up_process(fs_info->transaction_kthread);

  	return len;

  }

  BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);

  static ssize_t btrfs_nodesize_show(struct kobject *kobj,
  				struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%u
  ", fs_info->super_copy->nodesize);

  }

  BTRFS_ATTR(, nodesize, btrfs_nodesize_show);

  
  static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
  				struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%u
  ",
  			 fs_info->super_copy->sectorsize);

  }

  BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);

  
  static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
  				struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%u
  ", fs_info->super_copy->sectorsize);

  }

  BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);

  static ssize_t quota_override_show(struct kobject *kobj,
  				   struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  	int quota_override;
  
  	quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);

  	return scnprintf(buf, PAGE_SIZE, "%d
  ", quota_override);

  }
  
  static ssize_t quota_override_store(struct kobject *kobj,
  				    struct kobj_attribute *a,
  				    const char *buf, size_t len)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  	unsigned long knob;
  	int err;
  
  	if (!fs_info)
  		return -EPERM;
  
  	if (!capable(CAP_SYS_RESOURCE))
  		return -EPERM;
  
  	err = kstrtoul(buf, 10, &knob);
  	if (err)
  		return err;
  	if (knob > 1)
  		return -EINVAL;
  
  	if (knob)
  		set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
  	else
  		clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
  
  	return len;
  }

  BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);

  static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
  				struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

  	return scnprintf(buf, PAGE_SIZE, "%pU
  ",

  			fs_info->fs_devices->metadata_uuid);
  }
  
  BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);

  static ssize_t btrfs_checksum_show(struct kobject *kobj,
  				   struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  	u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);

  	return scnprintf(buf, PAGE_SIZE, "%s (%s)
  ",

  			btrfs_super_csum_name(csum_type),
  			crypto_shash_driver_name(fs_info->csum_shash));
  }
  
  BTRFS_ATTR(, checksum, btrfs_checksum_show);

  static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
  		struct kobj_attribute *a, char *buf)
  {
  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  	const char *str;
  
  	switch (READ_ONCE(fs_info->exclusive_operation)) {
  		case  BTRFS_EXCLOP_NONE:
  			str = "none
  ";
  			break;
  		case BTRFS_EXCLOP_BALANCE:
  			str = "balance
  ";
  			break;
  		case BTRFS_EXCLOP_DEV_ADD:
  			str = "device add
  ";
  			break;
  		case BTRFS_EXCLOP_DEV_REMOVE:
  			str = "device remove
  ";
  			break;
  		case BTRFS_EXCLOP_DEV_REPLACE:
  			str = "device replace
  ";
  			break;
  		case BTRFS_EXCLOP_RESIZE:
  			str = "resize
  ";
  			break;
  		case BTRFS_EXCLOP_SWAP_ACTIVATE:
  			str = "swap activate
  ";
  			break;
  		default:
  			str = "UNKNOWN
  ";
  			break;
  	}
  	return scnprintf(buf, PAGE_SIZE, "%s", str);
  }
  BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);

  static const struct attribute *btrfs_attrs[] = {

  	BTRFS_ATTR_PTR(, label),
  	BTRFS_ATTR_PTR(, nodesize),
  	BTRFS_ATTR_PTR(, sectorsize),
  	BTRFS_ATTR_PTR(, clone_alignment),
  	BTRFS_ATTR_PTR(, quota_override),

  	BTRFS_ATTR_PTR(, metadata_uuid),

  	BTRFS_ATTR_PTR(, checksum),

  	BTRFS_ATTR_PTR(, exclusive_operation),

  	NULL,
  };

  static void btrfs_release_fsid_kobj(struct kobject *kobj)

  {

  	struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);

  	memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));

  	complete(&fs_devs->kobj_unregister);

  }
  
  static struct kobj_type btrfs_ktype = {
  	.sysfs_ops	= &kobj_sysfs_ops,

  	.release	= btrfs_release_fsid_kobj,

  };

  static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
  {
  	if (kobj->ktype != &btrfs_ktype)
  		return NULL;

  	return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);

  }

  static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
  {
  	if (kobj->ktype != &btrfs_ktype)
  		return NULL;

  	return to_fs_devs(kobj)->fs_info;

  }

  #define NUM_FEATURE_BITS 64

  #define BTRFS_FEATURE_NAME_MAX 13
  static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
  static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];

  static const u64 supported_feature_masks[FEAT_MAX] = {

  	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
  	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
  	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
  };
  
  static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
  {
  	int set;
  
  	for (set = 0; set < FEAT_MAX; set++) {
  		int i;
  		struct attribute *attrs[2];
  		struct attribute_group agroup = {
  			.name = "features",
  			.attrs = attrs,
  		};
  		u64 features = get_features(fs_info, set);
  		features &= ~supported_feature_masks[set];
  
  		if (!features)
  			continue;
  
  		attrs[1] = NULL;
  		for (i = 0; i < NUM_FEATURE_BITS; i++) {
  			struct btrfs_feature_attr *fa;
  
  			if (!(features & (1ULL << i)))
  				continue;
  
  			fa = &btrfs_feature_attrs[set][i];
  			attrs[0] = &fa->kobj_attr.attr;
  			if (add) {
  				int ret;

  				ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,

  							&agroup);
  				if (ret)
  					return ret;
  			} else

  				sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,

  						    &agroup);
  		}
  
  	}
  	return 0;
  }

  static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)

  {

  	if (fs_devs->devinfo_kobj) {
  		kobject_del(fs_devs->devinfo_kobj);
  		kobject_put(fs_devs->devinfo_kobj);
  		fs_devs->devinfo_kobj = NULL;
  	}

  	if (fs_devs->devices_kobj) {
  		kobject_del(fs_devs->devices_kobj);
  		kobject_put(fs_devs->devices_kobj);
  		fs_devs->devices_kobj = NULL;

  	}

  	if (fs_devs->fsid_kobj.state_initialized) {
  		kobject_del(&fs_devs->fsid_kobj);
  		kobject_put(&fs_devs->fsid_kobj);

  		wait_for_completion(&fs_devs->kobj_unregister);
  	}

  }

  /* when fs_devs is NULL it will remove all fsid kobject */

  void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)

  {
  	struct list_head *fs_uuids = btrfs_get_fs_uuids();
  
  	if (fs_devs) {
  		__btrfs_sysfs_remove_fsid(fs_devs);
  		return;
  	}

  	list_for_each_entry(fs_devs, fs_uuids, fs_list) {

  		__btrfs_sysfs_remove_fsid(fs_devs);
  	}
  }

  static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
  {
  	struct btrfs_device *device;

  	struct btrfs_fs_devices *seed;

  
  	list_for_each_entry(device, &fs_devices->devices, dev_list)
  		btrfs_sysfs_remove_device(device);

  
  	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
  		list_for_each_entry(device, &seed->devices, dev_list)
  			btrfs_sysfs_remove_device(device);
  	}

  }

  void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)

  {

  	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;

  	sysfs_remove_link(fsid_kobj, "bdi");

  	if (fs_info->space_info_kobj) {
  		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
  		kobject_del(fs_info->space_info_kobj);
  		kobject_put(fs_info->space_info_kobj);
  	}

  #ifdef CONFIG_BTRFS_DEBUG

  	if (fs_info->discard_debug_kobj) {
  		sysfs_remove_files(fs_info->discard_debug_kobj,
  				   discard_debug_attrs);
  		kobject_del(fs_info->discard_debug_kobj);
  		kobject_put(fs_info->discard_debug_kobj);
  	}

  	if (fs_info->debug_kobj) {
  		sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
  		kobject_del(fs_info->debug_kobj);
  		kobject_put(fs_info->debug_kobj);
  	}

  #endif

  	addrm_unknown_feature_attrs(fs_info, false);

  	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
  	sysfs_remove_files(fsid_kobj, btrfs_attrs);

  	btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);

  }

  static const char * const btrfs_feature_set_names[FEAT_MAX] = {

  	[FEAT_COMPAT]	 = "compat",
  	[FEAT_COMPAT_RO] = "compat_ro",
  	[FEAT_INCOMPAT]	 = "incompat",
  };

  const char *btrfs_feature_set_name(enum btrfs_feature_set set)

  {
  	return btrfs_feature_set_names[set];
  }

  char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
  {
  	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
  	int len = 0;
  	int i;
  	char *str;
  
  	str = kmalloc(bufsize, GFP_KERNEL);
  	if (!str)
  		return str;
  
  	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
  		const char *name;
  
  		if (!(flags & (1ULL << i)))
  			continue;
  
  		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;

  		len += scnprintf(str + len, bufsize - len, "%s%s",

  				len ? "," : "", name);
  	}
  
  	return str;
  }

  static void init_feature_attrs(void)
  {
  	struct btrfs_feature_attr *fa;
  	int set, i;
  
  	BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
  		     ARRAY_SIZE(btrfs_feature_attrs));
  	BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
  		     ARRAY_SIZE(btrfs_feature_attrs[0]));

  	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
  	memset(btrfs_unknown_feature_names, 0,
  	       sizeof(btrfs_unknown_feature_names));

  	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
  		struct btrfs_feature_attr *sfa;
  		struct attribute *a = btrfs_supported_feature_attrs[i];

  		int bit;

  		sfa = attr_to_btrfs_feature_attr(a);

  		bit = ilog2(sfa->feature_bit);
  		fa = &btrfs_feature_attrs[sfa->feature_set][bit];

  
  		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
  	}
  
  	for (set = 0; set < FEAT_MAX; set++) {
  		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
  			char *name = btrfs_unknown_feature_names[set][i];
  			fa = &btrfs_feature_attrs[set][i];
  
  			if (fa->kobj_attr.attr.name)
  				continue;

  			snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",

  				 btrfs_feature_set_names[set], i);
  
  			fa->kobj_attr.attr.name = name;
  			fa->kobj_attr.attr.mode = S_IRUGO;
  			fa->feature_set = set;
  			fa->feature_bit = 1ULL << i;
  		}
  	}
  }

  /*
   * Create a sysfs entry for a given block group type at path
   * /sys/fs/btrfs/UUID/allocation/data/TYPE
   */

  void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)

  {
  	struct btrfs_fs_info *fs_info = cache->fs_info;
  	struct btrfs_space_info *space_info = cache->space_info;
  	struct raid_kobject *rkobj;
  	const int index = btrfs_bg_flags_to_raid_index(cache->flags);
  	unsigned int nofs_flag;
  	int ret;
  
  	/*
  	 * Setup a NOFS context because kobject_add(), deep in its call chain,
  	 * does GFP_KERNEL allocations, and we are often called in a context
  	 * where if reclaim is triggered we can deadlock (we are either holding
  	 * a transaction handle or some lock required for a transaction
  	 * commit).
  	 */
  	nofs_flag = memalloc_nofs_save();
  
  	rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
  	if (!rkobj) {
  		memalloc_nofs_restore(nofs_flag);
  		btrfs_warn(cache->fs_info,
  				"couldn't alloc memory for raid level kobject");
  		return;
  	}
  
  	rkobj->flags = cache->flags;
  	kobject_init(&rkobj->kobj, &btrfs_raid_ktype);

  
  	/*
  	 * We call this either on mount, or if we've created a block group for a
  	 * new index type while running (i.e. when restriping).  The running
  	 * case is tricky because we could race with other threads, so we need
  	 * to have this check to make sure we didn't already init the kobject.
  	 *
  	 * We don't have to protect on the free side because it only happens on
  	 * unmount.
  	 */
  	spin_lock(&space_info->lock);
  	if (space_info->block_group_kobjs[index]) {
  		spin_unlock(&space_info->lock);
  		kobject_put(&rkobj->kobj);
  		return;
  	} else {
  		space_info->block_group_kobjs[index] = &rkobj->kobj;
  	}
  	spin_unlock(&space_info->lock);

  	ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
  			  btrfs_bg_type_to_raid_name(rkobj->flags));
  	memalloc_nofs_restore(nofs_flag);
  	if (ret) {

  		spin_lock(&space_info->lock);
  		space_info->block_group_kobjs[index] = NULL;
  		spin_unlock(&space_info->lock);

  		kobject_put(&rkobj->kobj);
  		btrfs_warn(fs_info,
  			"failed to add kobject for block cache, ignoring");
  		return;
  	}

  }

  /*
   * Remove sysfs directories for all block group types of a given space info and
   * the space info as well
   */
  void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
  {
  	int i;
  
  	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
  		struct kobject *kobj;
  
  		kobj = space_info->block_group_kobjs[i];
  		space_info->block_group_kobjs[i] = NULL;
  		if (kobj) {
  			kobject_del(kobj);
  			kobject_put(kobj);
  		}
  	}
  	kobject_del(&space_info->kobj);
  	kobject_put(&space_info->kobj);
  }

  static const char *alloc_name(u64 flags)
  {
  	switch (flags) {
  	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
  		return "mixed";
  	case BTRFS_BLOCK_GROUP_METADATA:
  		return "metadata";
  	case BTRFS_BLOCK_GROUP_DATA:
  		return "data";
  	case BTRFS_BLOCK_GROUP_SYSTEM:
  		return "system";
  	default:
  		WARN_ON(1);
  		return "invalid-combination";
  	};
  }
  
  /*
   * Create a sysfs entry for a space info type at path
   * /sys/fs/btrfs/UUID/allocation/TYPE
   */
  int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
  				    struct btrfs_space_info *space_info)
  {
  	int ret;
  
  	ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
  				   fs_info->space_info_kobj, "%s",
  				   alloc_name(space_info->flags));
  	if (ret) {
  		kobject_put(&space_info->kobj);
  		return ret;
  	}
  
  	return 0;
  }

  void btrfs_sysfs_remove_device(struct btrfs_device *device)

  {
  	struct hd_struct *disk;
  	struct kobject *disk_kobj;

  	struct kobject *devices_kobj;

  	/*
  	 * Seed fs_devices devices_kobj aren't used, fetch kobject from the
  	 * fs_info::fs_devices.
  	 */
  	devices_kobj = device->fs_info->fs_devices->devices_kobj;
  	ASSERT(devices_kobj);

  	if (device->bdev) {
  		disk = device->bdev->bd_part;
  		disk_kobj = &part_to_dev(disk)->kobj;
  		sysfs_remove_link(devices_kobj, disk_kobj->name);
  	}

  	if (device->devid_kobj.state_initialized) {
  		kobject_del(&device->devid_kobj);
  		kobject_put(&device->devid_kobj);
  		wait_for_completion(&device->kobj_unregister);
  	}
  }

  static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
  					         struct kobj_attribute *a,
  					         char *buf)
  {
  	int val;
  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
  						   devid_kobj);
  
  	val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);

  	return scnprintf(buf, PAGE_SIZE, "%d
  ", val);

  }
  BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);

  static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,

  					struct kobj_attribute *a, char *buf)
  {
  	int val;
  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
  						   devid_kobj);
  
  	val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);

  	return scnprintf(buf, PAGE_SIZE, "%d
  ", val);

  }

  BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);

  
  static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
  					         struct kobj_attribute *a,
  					         char *buf)
  {
  	int val;
  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
  						   devid_kobj);
  
  	val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);

  	return scnprintf(buf, PAGE_SIZE, "%d
  ", val);

  }
  BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
  
  static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
  					    struct kobj_attribute *a, char *buf)
  {
  	int val;
  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
  						   devid_kobj);
  
  	val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);

  	return scnprintf(buf, PAGE_SIZE, "%d
  ", val);

  }
  BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
  
  static struct attribute *devid_attrs[] = {
  	BTRFS_ATTR_PTR(devid, in_fs_metadata),
  	BTRFS_ATTR_PTR(devid, missing),
  	BTRFS_ATTR_PTR(devid, replace_target),
  	BTRFS_ATTR_PTR(devid, writeable),
  	NULL
  };
  ATTRIBUTE_GROUPS(devid);
  
  static void btrfs_release_devid_kobj(struct kobject *kobj)
  {
  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
  						   devid_kobj);
  
  	memset(&device->devid_kobj, 0, sizeof(struct kobject));
  	complete(&device->kobj_unregister);
  }
  
  static struct kobj_type devid_ktype = {
  	.sysfs_ops	= &kobj_sysfs_ops,
  	.default_groups = devid_groups,
  	.release	= btrfs_release_devid_kobj,
  };

  int btrfs_sysfs_add_device(struct btrfs_device *device)

  {

  	int ret;

  	unsigned int nofs_flag;

  	struct kobject *devices_kobj;
  	struct kobject *devinfo_kobj;

  	/*
  	 * Make sure we use the fs_info::fs_devices to fetch the kobjects even
  	 * for the seed fs_devices
  	 */
  	devices_kobj = device->fs_info->fs_devices->devices_kobj;
  	devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
  	ASSERT(devices_kobj);
  	ASSERT(devinfo_kobj);

  	nofs_flag = memalloc_nofs_save();

  	if (device->bdev) {
  		struct hd_struct *disk;
  		struct kobject *disk_kobj;

  		disk = device->bdev->bd_part;
  		disk_kobj = &part_to_dev(disk)->kobj;

  		ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
  		if (ret) {
  			btrfs_warn(device->fs_info,
  				"creating sysfs device link for devid %llu failed: %d",
  				device->devid, ret);
  			goto out;

  		}

  	}

  	init_completion(&device->kobj_unregister);
  	ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
  				   devinfo_kobj, "%llu", device->devid);
  	if (ret) {
  		kobject_put(&device->devid_kobj);
  		btrfs_warn(device->fs_info,
  			   "devinfo init for devid %llu failed: %d",
  			   device->devid, ret);

  	}

  
  out:

  	memalloc_nofs_restore(nofs_flag);

  	return ret;
  }

  static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)

  {
  	int ret;

  	struct btrfs_device *device;

  	struct btrfs_fs_devices *seed;

  
  	list_for_each_entry(device, &fs_devices->devices, dev_list) {
  		ret = btrfs_sysfs_add_device(device);
  		if (ret)

  			goto fail;

  	}

  	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
  		list_for_each_entry(device, &seed->devices, dev_list) {
  			ret = btrfs_sysfs_add_device(device);
  			if (ret)

  				goto fail;

  		}
  	}

  	return 0;

  
  fail:
  	btrfs_sysfs_remove_fs_devices(fs_devices);
  	return ret;

  }

  void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
  {
  	int ret;
  
  	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
  	if (ret)
  		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed
  ",
  			action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
  			&disk_to_dev(bdev->bd_disk)->kobj);
  }

  void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)

  {
  	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
  
  	/*
  	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
  	 * directory
  	 */

  	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);

  	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
  		btrfs_warn(fs_devices->fs_info,
  				"sysfs: failed to create fsid for sprout");
  }

  void btrfs_sysfs_update_devid(struct btrfs_device *device)
  {
  	char tmp[24];
  
  	snprintf(tmp, sizeof(tmp), "%llu", device->devid);
  
  	if (kobject_rename(&device->devid_kobj, tmp))
  		btrfs_warn(device->fs_devices->fs_info,
  			   "sysfs: failed to update devid for %llu",
  			   device->devid);
  }

  /* /sys/fs/btrfs/ entry */
  static struct kset *btrfs_kset;

  /*

   * Creates:
   *		/sys/fs/btrfs/UUID
   *

   * Can be called by the device discovery thread.

   */

  int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)

  {
  	int error;

  	init_completion(&fs_devs->kobj_unregister);

  	fs_devs->fsid_kobj.kset = btrfs_kset;

  	error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
  				     "%pU", fs_devs->fsid);

  	if (error) {
  		kobject_put(&fs_devs->fsid_kobj);
  		return error;
  	}

  	fs_devs->devices_kobj = kobject_create_and_add("devices",
  						       &fs_devs->fsid_kobj);
  	if (!fs_devs->devices_kobj) {
  		btrfs_err(fs_devs->fs_info,
  			  "failed to init sysfs device interface");

  		btrfs_sysfs_remove_fsid(fs_devs);

  		return -ENOMEM;
  	}

  	fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
  						       &fs_devs->fsid_kobj);
  	if (!fs_devs->devinfo_kobj) {
  		btrfs_err(fs_devs->fs_info,
  			  "failed to init sysfs devinfo kobject");
  		btrfs_sysfs_remove_fsid(fs_devs);
  		return -ENOMEM;
  	}

  	return 0;

  }

  int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)

  {
  	int error;

  	struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;

  	struct kobject *fsid_kobj = &fs_devs->fsid_kobj;

  	error = btrfs_sysfs_add_fs_devices(fs_devs);

  	if (error)

  		return error;

  	error = sysfs_create_files(fsid_kobj, btrfs_attrs);

  	if (error) {

  		btrfs_sysfs_remove_fs_devices(fs_devs);

  		return error;
  	}

  	error = sysfs_create_group(fsid_kobj,

  				   &btrfs_feature_attr_group);
  	if (error)
  		goto failure;

  #ifdef CONFIG_BTRFS_DEBUG

  	fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
  	if (!fs_info->debug_kobj) {
  		error = -ENOMEM;
  		goto failure;
  	}
  
  	error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);

  	if (error)
  		goto failure;

  
  	/* Discard directory */
  	fs_info->discard_debug_kobj = kobject_create_and_add("discard",
  						     fs_info->debug_kobj);
  	if (!fs_info->discard_debug_kobj) {
  		error = -ENOMEM;
  		goto failure;
  	}
  
  	error = sysfs_create_files(fs_info->discard_debug_kobj,
  				   discard_debug_attrs);
  	if (error)
  		goto failure;

  #endif

  	error = addrm_unknown_feature_attrs(fs_info, true);

  	if (error)
  		goto failure;

  	error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
  	if (error)
  		goto failure;

  	fs_info->space_info_kobj = kobject_create_and_add("allocation",

  						  fsid_kobj);

  	if (!fs_info->space_info_kobj) {
  		error = -ENOMEM;
  		goto failure;
  	}
  
  	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
  	if (error)
  		goto failure;

  	return 0;
  failure:

  	btrfs_sysfs_remove_mounted(fs_info);

  	return error;
  }

  static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
  {
  	return to_fs_info(kobj->parent->parent);
  }
  
  #define QGROUP_ATTR(_member, _show_name)					\
  static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,		\
  					   struct kobj_attribute *a,		\
  					   char *buf)				\
  {										\
  	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
  	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
  			struct btrfs_qgroup, kobj);				\
  	return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);	\
  }										\
  BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
  
  #define QGROUP_RSV_ATTR(_name, _type)						\
  static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,	\
  					     struct kobj_attribute *a,		\
  					     char *buf)				\
  {										\
  	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
  	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
  			struct btrfs_qgroup, kobj);				\
  	return btrfs_show_u64(&qgroup->rsv.values[_type],			\
  			&fs_info->qgroup_lock, buf);				\
  }										\
  BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
  
  QGROUP_ATTR(rfer, referenced);
  QGROUP_ATTR(excl, exclusive);
  QGROUP_ATTR(max_rfer, max_referenced);
  QGROUP_ATTR(max_excl, max_exclusive);
  QGROUP_ATTR(lim_flags, limit_flags);
  QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
  QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
  QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
  
  static struct attribute *qgroup_attrs[] = {
  	BTRFS_ATTR_PTR(qgroup, referenced),
  	BTRFS_ATTR_PTR(qgroup, exclusive),
  	BTRFS_ATTR_PTR(qgroup, max_referenced),
  	BTRFS_ATTR_PTR(qgroup, max_exclusive),
  	BTRFS_ATTR_PTR(qgroup, limit_flags),
  	BTRFS_ATTR_PTR(qgroup, rsv_data),
  	BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
  	BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
  	NULL
  };
  ATTRIBUTE_GROUPS(qgroup);
  
  static void qgroup_release(struct kobject *kobj)
  {
  	struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
  
  	memset(&qgroup->kobj, 0, sizeof(*kobj));
  }
  
  static struct kobj_type qgroup_ktype = {
  	.sysfs_ops = &kobj_sysfs_ops,
  	.release = qgroup_release,
  	.default_groups = qgroup_groups,
  };
  
  int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
  				struct btrfs_qgroup *qgroup)
  {
  	struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
  	int ret;
  
  	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
  		return 0;
  	if (qgroup->kobj.state_initialized)
  		return 0;
  	if (!qgroups_kobj)
  		return -EINVAL;
  
  	ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
  			"%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
  			btrfs_qgroup_subvolid(qgroup->qgroupid));
  	if (ret < 0)
  		kobject_put(&qgroup->kobj);
  
  	return ret;
  }
  
  void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
  {
  	struct btrfs_qgroup *qgroup;
  	struct btrfs_qgroup *next;
  
  	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
  		return;
  
  	rbtree_postorder_for_each_entry_safe(qgroup, next,
  					     &fs_info->qgroup_tree, node)
  		btrfs_sysfs_del_one_qgroup(fs_info, qgroup);

  	if (fs_info->qgroups_kobj) {
  		kobject_del(fs_info->qgroups_kobj);
  		kobject_put(fs_info->qgroups_kobj);
  		fs_info->qgroups_kobj = NULL;
  	}

  }
  
  /* Called when qgroups get initialized, thus there is no need for locking */
  int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
  {
  	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
  	struct btrfs_qgroup *qgroup;
  	struct btrfs_qgroup *next;
  	int ret = 0;
  
  	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
  		return 0;
  
  	ASSERT(fsid_kobj);
  	if (fs_info->qgroups_kobj)
  		return 0;
  
  	fs_info->qgroups_kobj = kobject_create_and_add("qgroups", fsid_kobj);
  	if (!fs_info->qgroups_kobj) {
  		ret = -ENOMEM;
  		goto out;
  	}
  	rbtree_postorder_for_each_entry_safe(qgroup, next,
  					     &fs_info->qgroup_tree, node) {
  		ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
  		if (ret < 0)
  			goto out;
  	}
  
  out:
  	if (ret < 0)
  		btrfs_sysfs_del_qgroups(fs_info);
  	return ret;
  }
  
  void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
  				struct btrfs_qgroup *qgroup)
  {
  	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
  		return;
  
  	if (qgroup->kobj.state_initialized) {
  		kobject_del(&qgroup->kobj);
  		kobject_put(&qgroup->kobj);
  	}
  }

  
  /*
   * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
   * values in superblock. Call after any changes to incompat/compat_ro flags
   */
  void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
  		u64 bit, enum btrfs_feature_set set)
  {
  	struct btrfs_fs_devices *fs_devs;
  	struct kobject *fsid_kobj;

  	u64 __maybe_unused features;
  	int __maybe_unused ret;

  
  	if (!fs_info)
  		return;

  	/*
  	 * See 14e46e04958df74 and e410e34fad913dd, feature bit updates are not
  	 * safe when called from some contexts (eg. balance)
  	 */

  	features = get_features(fs_info, set);
  	ASSERT(bit & supported_feature_masks[set]);
  
  	fs_devs = fs_info->fs_devices;
  	fsid_kobj = &fs_devs->fsid_kobj;

  	if (!fsid_kobj->state_initialized)
  		return;

  	/*
  	 * FIXME: this is too heavy to update just one value, ideally we'd like
  	 * to use sysfs_update_group but some refactoring is needed first.
  	 */
  	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
  	ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
  }

  int __init btrfs_init_sysfs(void)

  {

  	int ret;

  	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
  	if (!btrfs_kset)
  		return -ENOMEM;

  	init_feature_attrs();

  	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);

  	if (ret)
  		goto out2;

  	ret = sysfs_merge_group(&btrfs_kset->kobj,
  				&btrfs_static_feature_attr_group);
  	if (ret)
  		goto out_remove_group;

  #ifdef CONFIG_BTRFS_DEBUG
  	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
  	if (ret)
  		goto out2;
  #endif

  	return 0;

  
  out_remove_group:
  	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);

  out2:

  	kset_unregister(btrfs_kset);

  	return ret;

  }

  void __cold btrfs_exit_sysfs(void)

  {

  	sysfs_unmerge_group(&btrfs_kset->kobj,
  			    &btrfs_static_feature_attr_group);

  	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);

  #ifdef CONFIG_BTRFS_DEBUG
  	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
  #endif

  	kset_unregister(btrfs_kset);

  }