diff options
| author | Omar Sandoval | 2019-12-05 10:36:04 -0800 |
|---|---|---|
| committer | David Sterba | 2020-01-20 16:40:53 +0100 |
| commit | 6bb6b51447ca114980c2debab8241ae21f8557c7 (patch) | |
| tree | 0a5455462faac7e7b63912a7eebc710589df96c9 /fs/btrfs | |
| parent | b38f4cbd65fb56180f8d283f410ddec3965c93bf (diff) | |
btrfs: use simple_dir_inode_operations for placeholder subvolume directory
When you snapshot a subvolume containing a subvolume, you get a
placeholder directory where the subvolume would be. These directories
have their own btrfs_dir_ro_inode_operations.
Al pointed out [1] that these directories can use simple_lookup()
instead of btrfs_lookup(), as they are always empty. Furthermore, they
can use the default generic_permission() instead of btrfs_permission();
the additional checks in the latter don't matter because we can't write
to the directory anyways. Finally, they can use the default
generic_update_time() instead of btrfs_update_time(), as the inode
doesn't exist on disk and doesn't need any special handling.
All together, this means that we can get rid of
btrfs_dir_ro_inode_operations and use simple_dir_inode_operations
instead.
1: https://lore.kernel.org/linux-btrfs/20190929052934.GY26530@ZenIV.linux.org.uk/
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/inode.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 73c148eaae9f..4b2d151b6d7b 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -64,7 +64,6 @@ struct btrfs_dio_data { static const struct inode_operations btrfs_dir_inode_operations; static const struct inode_operations btrfs_symlink_inode_operations; -static const struct inode_operations btrfs_dir_ro_inode_operations; static const struct inode_operations btrfs_special_inode_operations; static const struct inode_operations btrfs_file_inode_operations; static const struct address_space_operations btrfs_aops; @@ -5869,7 +5868,11 @@ static struct inode *new_simple_dir(struct super_block *s, set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags); inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID; - inode->i_op = &btrfs_dir_ro_inode_operations; + /* + * We only need lookup, the rest is read-only and there's no inode + * associated with the dentry + */ + inode->i_op = &simple_dir_inode_operations; inode->i_opflags &= ~IOP_XATTR; inode->i_fop = &simple_dir_operations; inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO; @@ -11010,11 +11013,6 @@ static const struct inode_operations btrfs_dir_inode_operations = { .update_time = btrfs_update_time, .tmpfile = btrfs_tmpfile, }; -static const struct inode_operations btrfs_dir_ro_inode_operations = { - .lookup = btrfs_lookup, - .permission = btrfs_permission, - .update_time = btrfs_update_time, -}; static const struct file_operations btrfs_dir_file_operations = { .llseek = generic_file_llseek, |