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authorDavid Sterba <dsterba@suse.com>2020-05-15 19:35:55 +0200
committerDavid Sterba <dsterba@suse.com>2020-05-25 11:25:36 +0200
commit56e9357a1e8167134388d4c70654795353765c7b (patch)
treee89265fd992d94c54fffb639cf4ee39bd268cfdb /fs/btrfs
parent1dae7e0e58b484eaa43d530f211098fdeeb0f404 (diff)
downloadlinux-56e9357a1e8167134388d4c70654795353765c7b.tar.bz2
btrfs: simplify root lookup by id
The main function to lookup a root by its id btrfs_get_fs_root takes the whole key, while only using the objectid. The value of offset is preset to (u64)-1 but not actually used until btrfs_find_root that does the actual search. Switch btrfs_get_fs_root to use only objectid and remove all local variables that existed just for the lookup. The actual key for search is set up in btrfs_get_fs_root, reusing another key variable. Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/backref.c13
-rw-r--r--fs/btrfs/disk-io.c39
-rw-r--r--fs/btrfs/disk-io.h3
-rw-r--r--fs/btrfs/export.c6
-rw-r--r--fs/btrfs/file.c6
-rw-r--r--fs/btrfs/inode.c2
-rw-r--r--fs/btrfs/ioctl.c28
-rw-r--r--fs/btrfs/relocation.c8
-rw-r--r--fs/btrfs/root-tree.c12
-rw-r--r--fs/btrfs/scrub.c6
-rw-r--r--fs/btrfs/send.c15
-rw-r--r--fs/btrfs/super.c5
-rw-r--r--fs/btrfs/transaction.c2
-rw-r--r--fs/btrfs/tree-log.c8
-rw-r--r--fs/btrfs/uuid-tree.c6
15 files changed, 46 insertions, 113 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 41ef3fa91864..d888e71e66b6 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -538,18 +538,13 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
const u64 *extent_item_pos, bool ignore_offset)
{
struct btrfs_root *root;
- struct btrfs_key root_key;
struct extent_buffer *eb;
int ret = 0;
int root_level;
int level = ref->level;
struct btrfs_key search_key = ref->key_for_search;
- root_key.objectid = ref->root_id;
- root_key.type = BTRFS_ROOT_ITEM_KEY;
- root_key.offset = (u64)-1;
-
- root = btrfs_get_fs_root(fs_info, &root_key, false);
+ root = btrfs_get_fs_root(fs_info, ref->root_id, false);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out_free;
@@ -2690,16 +2685,12 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
struct btrfs_backref_edge *edge;
struct extent_buffer *eb;
struct btrfs_root *root;
- struct btrfs_key root_key;
struct rb_node *rb_node;
int level;
bool need_check = true;
int ret;
- root_key.objectid = ref_key->offset;
- root_key.type = BTRFS_ROOT_ITEM_KEY;
- root_key.offset = (u64)-1;
- root = btrfs_get_fs_root(fs_info, &root_key, false);
+ root = btrfs_get_fs_root(fs_info, ref_key->offset, false);
if (IS_ERR(root))
return PTR_ERR(root);
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7b66a8e4ca54..f2f2864f5978 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1534,35 +1534,34 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
- struct btrfs_key *location,
- bool check_ref)
+ u64 objectid, bool check_ref)
{
struct btrfs_root *root;
struct btrfs_path *path;
struct btrfs_key key;
int ret;
- if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
+ if (objectid == BTRFS_ROOT_TREE_OBJECTID)
return btrfs_grab_root(fs_info->tree_root);
- if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
+ if (objectid == BTRFS_EXTENT_TREE_OBJECTID)
return btrfs_grab_root(fs_info->extent_root);
- if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
+ if (objectid == BTRFS_CHUNK_TREE_OBJECTID)
return btrfs_grab_root(fs_info->chunk_root);
- if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
+ if (objectid == BTRFS_DEV_TREE_OBJECTID)
return btrfs_grab_root(fs_info->dev_root);
- if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
+ if (objectid == BTRFS_CSUM_TREE_OBJECTID)
return btrfs_grab_root(fs_info->csum_root);
- if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
+ if (objectid == BTRFS_QUOTA_TREE_OBJECTID)
return btrfs_grab_root(fs_info->quota_root) ?
fs_info->quota_root : ERR_PTR(-ENOENT);
- if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
+ if (objectid == BTRFS_UUID_TREE_OBJECTID)
return btrfs_grab_root(fs_info->uuid_root) ?
fs_info->uuid_root : ERR_PTR(-ENOENT);
- if (location->objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
+ if (objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
return btrfs_grab_root(fs_info->free_space_root) ?
fs_info->free_space_root : ERR_PTR(-ENOENT);
again:
- root = btrfs_lookup_fs_root(fs_info, location->objectid);
+ root = btrfs_lookup_fs_root(fs_info, objectid);
if (root) {
if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
btrfs_put_root(root);
@@ -1571,7 +1570,10 @@ again:
return root;
}
- root = btrfs_read_tree_root(fs_info->tree_root, location);
+ key.objectid = objectid;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+ root = btrfs_read_tree_root(fs_info->tree_root, &key);
if (IS_ERR(root))
return root;
@@ -1591,7 +1593,7 @@ again:
}
key.objectid = BTRFS_ORPHAN_OBJECTID;
key.type = BTRFS_ORPHAN_ITEM_KEY;
- key.offset = location->objectid;
+ key.offset = objectid;
ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
btrfs_free_path(path);
@@ -2293,8 +2295,8 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
* This tree can share blocks with some other fs tree during relocation
* and we need a proper setup by btrfs_get_fs_root
*/
- location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
- root = btrfs_get_fs_root(tree_root->fs_info, &location, true);
+ root = btrfs_get_fs_root(tree_root->fs_info,
+ BTRFS_DATA_RELOC_TREE_OBJECTID, true);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out;
@@ -2839,7 +2841,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
u64 generation;
u64 features;
u16 csum_type;
- struct btrfs_key location;
struct btrfs_super_block *disk_super;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *tree_root;
@@ -3253,11 +3254,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
}
}
- location.objectid = BTRFS_FS_TREE_OBJECTID;
- location.type = BTRFS_ROOT_ITEM_KEY;
- location.offset = 0;
-
- fs_info->fs_root = btrfs_get_fs_root(fs_info, &location, true);
+ fs_info->fs_root = btrfs_get_fs_root(fs_info, BTRFS_FS_TREE_OBJECTID, true);
if (IS_ERR(fs_info->fs_root)) {
err = PTR_ERR(fs_info->fs_root);
btrfs_warn(fs_info, "failed to read fs tree: %d", err);
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 734bc5270b6a..bf43245406c4 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -66,8 +66,7 @@ int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);
struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
- struct btrfs_key *key,
- bool check_ref);
+ u64 objectid, bool check_ref);
void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);
int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info);
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 2bb25d2dc44b..e7cc98b4d7dc 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -69,11 +69,7 @@ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
if (objectid < BTRFS_FIRST_FREE_OBJECTID)
return ERR_PTR(-ESTALE);
- key.objectid = root_objectid;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
-
- root = btrfs_get_fs_root(fs_info, &key, true);
+ root = btrfs_get_fs_root(fs_info, root_objectid, true);
if (IS_ERR(root))
return ERR_CAST(root);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 606c2f3c1a38..14e1464870ab 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -281,11 +281,7 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
int ret;
/* get the inode */
- key.objectid = defrag->root;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
-
- inode_root = btrfs_get_fs_root(fs_info, &key, true);
+ inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
if (IS_ERR(inode_root)) {
ret = PTR_ERR(inode_root);
goto cleanup;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5be7820afe90..e0e8f74fa262 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5145,7 +5145,7 @@ static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
btrfs_release_path(path);
- new_root = btrfs_get_fs_root(fs_info, location, true);
+ new_root = btrfs_get_fs_root(fs_info, location->objectid, true);
if (IS_ERR(new_root)) {
err = PTR_ERR(new_root);
goto out;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 973236b72a97..05a8688ed4fd 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -660,7 +660,7 @@ static noinline int create_subvol(struct inode *dir,
goto fail;
key.offset = (u64)-1;
- new_root = btrfs_get_fs_root(fs_info, &key, true);
+ new_root = btrfs_get_fs_root(fs_info, objectid, true);
if (IS_ERR(new_root)) {
ret = PTR_ERR(new_root);
btrfs_abort_transaction(trans, ret);
@@ -2139,10 +2139,7 @@ static noinline int search_ioctl(struct inode *inode,
/* search the root of the inode that was passed */
root = btrfs_grab_root(BTRFS_I(inode)->root);
} else {
- key.objectid = sk->tree_id;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
- root = btrfs_get_fs_root(info, &key, true);
+ root = btrfs_get_fs_root(info, sk->tree_id, true);
if (IS_ERR(root)) {
btrfs_free_path(path);
return PTR_ERR(root);
@@ -2275,10 +2272,7 @@ static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX - 1];
- key.objectid = tree_id;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
- root = btrfs_get_fs_root(info, &key, true);
+ root = btrfs_get_fs_root(info, tree_id, true);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
root = NULL;
@@ -2371,10 +2365,7 @@ static int btrfs_search_path_in_tree_user(struct inode *inode,
if (dirid != upper_limit.objectid) {
ptr = &args->path[BTRFS_INO_LOOKUP_USER_PATH_MAX - 1];
- key.objectid = treeid;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
- root = btrfs_get_fs_root(fs_info, &key, true);
+ root = btrfs_get_fs_root(fs_info, treeid, true);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out;
@@ -2620,9 +2611,7 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
/* Get root_item of inode's subvolume */
key.objectid = BTRFS_I(inode)->root->root_key.objectid;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
- root = btrfs_get_fs_root(fs_info, &key, true);
+ root = btrfs_get_fs_root(fs_info, key.objectid, true);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out_free;
@@ -3290,7 +3279,6 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
struct btrfs_dir_item *di;
struct btrfs_trans_handle *trans;
struct btrfs_path *path = NULL;
- struct btrfs_key location;
struct btrfs_disk_key disk_key;
u64 objectid = 0;
u64 dir_id;
@@ -3311,11 +3299,7 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
if (!objectid)
objectid = BTRFS_FS_TREE_OBJECTID;
- location.objectid = objectid;
- location.type = BTRFS_ROOT_ITEM_KEY;
- location.offset = (u64)-1;
-
- new_root = btrfs_get_fs_root(fs_info, &location, true);
+ new_root = btrfs_get_fs_root(fs_info, objectid, true);
if (IS_ERR(new_root)) {
ret = PTR_ERR(new_root);
goto out;
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 68dd7a771e5e..19db203a8f3b 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -368,13 +368,7 @@ struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
u64 root_objectid)
{
- struct btrfs_key key;
-
- key.objectid = root_objectid;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
-
- return btrfs_get_fs_root(fs_info, &key, false);
+ return btrfs_get_fs_root(fs_info, root_objectid, false);
}
/*
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 668f22844017..c89697486366 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -210,7 +210,6 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
struct extent_buffer *leaf;
struct btrfs_path *path;
struct btrfs_key key;
- struct btrfs_key root_key;
struct btrfs_root *root;
int err = 0;
int ret;
@@ -223,10 +222,9 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
key.type = BTRFS_ORPHAN_ITEM_KEY;
key.offset = 0;
- root_key.type = BTRFS_ROOT_ITEM_KEY;
- root_key.offset = (u64)-1;
-
while (1) {
+ u64 root_objectid;
+
ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
if (ret < 0) {
err = ret;
@@ -250,10 +248,10 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
key.type != BTRFS_ORPHAN_ITEM_KEY)
break;
- root_key.objectid = key.offset;
+ root_objectid = key.offset;
key.offset++;
- root = btrfs_get_fs_root(fs_info, &root_key, false);
+ root = btrfs_get_fs_root(fs_info, root_objectid, false);
err = PTR_ERR_OR_ZERO(root);
if (err && err != -ENOENT) {
break;
@@ -270,7 +268,7 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
break;
}
err = btrfs_del_orphan_item(trans, tree_root,
- root_key.objectid);
+ root_objectid);
btrfs_end_transaction(trans);
if (err) {
btrfs_handle_fs_error(fs_info, err,
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 0f7740970553..016a025e36c7 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -647,13 +647,9 @@ static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
struct btrfs_fs_info *fs_info = swarn->dev->fs_info;
struct inode_fs_paths *ipath = NULL;
struct btrfs_root *local_root;
- struct btrfs_key root_key;
struct btrfs_key key;
- root_key.objectid = root;
- root_key.type = BTRFS_ROOT_ITEM_KEY;
- root_key.offset = (u64)-1;
- local_root = btrfs_get_fs_root(fs_info, &root_key, true);
+ local_root = btrfs_get_fs_root(fs_info, root, true);
if (IS_ERR(local_root)) {
ret = PTR_ERR(local_root);
goto err;
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 4f3b8d2bb56b..3ddd3b9778c7 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -7088,7 +7088,6 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
struct btrfs_root *send_root = BTRFS_I(file_inode(mnt_file))->root;
struct btrfs_fs_info *fs_info = send_root->fs_info;
struct btrfs_root *clone_root;
- struct btrfs_key key;
struct send_ctx *sctx = NULL;
u32 i;
u64 *clone_sources_tmp = NULL;
@@ -7217,11 +7216,8 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
}
for (i = 0; i < arg->clone_sources_count; i++) {
- key.objectid = clone_sources_tmp[i];
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
-
- clone_root = btrfs_get_fs_root(fs_info, &key, true);
+ clone_root = btrfs_get_fs_root(fs_info,
+ clone_sources_tmp[i], true);
if (IS_ERR(clone_root)) {
ret = PTR_ERR(clone_root);
goto out;
@@ -7252,11 +7248,8 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
}
if (arg->parent_root) {
- key.objectid = arg->parent_root;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
-
- sctx->parent_root = btrfs_get_fs_root(fs_info, &key, true);
+ sctx->parent_root = btrfs_get_fs_root(fs_info, arg->parent_root,
+ true);
if (IS_ERR(sctx->parent_root)) {
ret = PTR_ERR(sctx->parent_root);
goto out;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 438ecba26557..6bbf84a26501 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1102,10 +1102,7 @@ char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
btrfs_release_path(path);
- key.objectid = subvol_objectid;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
- fs_root = btrfs_get_fs_root(fs_info, &key, true);
+ fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
if (IS_ERR(fs_root)) {
ret = PTR_ERR(fs_root);
fs_root = NULL;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index a8cc2ddffc17..b359d4b17658 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1630,7 +1630,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
}
key.offset = (u64)-1;
- pending->snap = btrfs_get_fs_root(fs_info, &key, true);
+ pending->snap = btrfs_get_fs_root(fs_info, objectid, true);
if (IS_ERR(pending->snap)) {
ret = PTR_ERR(pending->snap);
btrfs_abort_transaction(trans, ret);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 60febf2082ee..d3662e102b2e 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -6112,7 +6112,6 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
struct btrfs_trans_handle *trans;
struct btrfs_key key;
struct btrfs_key found_key;
- struct btrfs_key tmp_key;
struct btrfs_root *log;
struct btrfs_fs_info *fs_info = log_root_tree->fs_info;
struct walk_control wc = {
@@ -6174,11 +6173,8 @@ again:
goto error;
}
- tmp_key.objectid = found_key.offset;
- tmp_key.type = BTRFS_ROOT_ITEM_KEY;
- tmp_key.offset = (u64)-1;
-
- wc.replay_dest = btrfs_get_fs_root(fs_info, &tmp_key, true);
+ wc.replay_dest = btrfs_get_fs_root(fs_info, found_key.offset,
+ true);
if (IS_ERR(wc.replay_dest)) {
ret = PTR_ERR(wc.replay_dest);
diff --git a/fs/btrfs/uuid-tree.c b/fs/btrfs/uuid-tree.c
index 76671a6bcb61..28525ad7ff8c 100644
--- a/fs/btrfs/uuid-tree.c
+++ b/fs/btrfs/uuid-tree.c
@@ -257,7 +257,6 @@ out:
static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
u8 *uuid, u8 type, u64 subvolid)
{
- struct btrfs_key key;
int ret = 0;
struct btrfs_root *subvol_root;
@@ -265,10 +264,7 @@ static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
goto out;
- key.objectid = subvolid;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
- subvol_root = btrfs_get_fs_root(fs_info, &key, true);
+ subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
if (IS_ERR(subvol_root)) {
ret = PTR_ERR(subvol_root);
if (ret == -ENOENT)