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| author | Josef Bacik <josef@toxicpanda.com> | 2020-02-14 22:11:47 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-03-23 17:02:00 +0100 |
| commit | c75e839414d3610e6487ae3145199c500d55f7f7 (patch) | |
| tree | 68e609a6362c4f259afc2e107fffac94e743a126 /fs/btrfs/export.c | |
| parent | btrfs: make btrfs_cleanup_fs_roots use the radix tree lock (diff) | |
| download | linux-c75e839414d3610e6487ae3145199c500d55f7f7.tar.xz linux-c75e839414d3610e6487ae3145199c500d55f7f7.zip | |
btrfs: kill the subvol_srcu
Now that we have proper root ref counting everywhere we can kill the
subvol_srcu.
* removal of fs_info::subvol_srcu reduces size of fs_info by 1176 bytes
* the refcount_t used for the references checks for accidental 0->1
in cases where the root lifetime would not be properly protected
* there's a leak detector for roots to catch unfreed roots at umount
time
* SRCU served us well over the years but is was not a proper
synchronization mechanism for some cases
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/export.c')
| -rw-r--r-- | fs/btrfs/export.c | 21 |
1 files changed, 4 insertions, 17 deletions
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c index 25bd4317bf5a..2bb25d2dc44b 100644 --- a/fs/btrfs/export.c +++ b/fs/btrfs/export.c @@ -65,8 +65,6 @@ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, struct btrfs_root *root; struct inode *inode; struct btrfs_key key; - int index; - int err = 0; if (objectid < BTRFS_FIRST_FREE_OBJECTID) return ERR_PTR(-ESTALE); @@ -75,13 +73,9 @@ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, key.type = BTRFS_ROOT_ITEM_KEY; key.offset = (u64)-1; - index = srcu_read_lock(&fs_info->subvol_srcu); - root = btrfs_get_fs_root(fs_info, &key, true); - if (IS_ERR(root)) { - err = PTR_ERR(root); - goto fail; - } + if (IS_ERR(root)) + return ERR_CAST(root); key.objectid = objectid; key.type = BTRFS_INODE_ITEM_KEY; @@ -89,12 +83,8 @@ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, inode = btrfs_iget(sb, &key, root); btrfs_put_root(root); - if (IS_ERR(inode)) { - err = PTR_ERR(inode); - goto fail; - } - - srcu_read_unlock(&fs_info->subvol_srcu, index); + if (IS_ERR(inode)) + return ERR_CAST(inode); if (check_generation && generation != inode->i_generation) { iput(inode); @@ -102,9 +92,6 @@ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, } return d_obtain_alias(inode); -fail: - srcu_read_unlock(&fs_info->subvol_srcu, index); - return ERR_PTR(err); } static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, |