From: Omar Sandoval <osandov@xxxxxx> 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@xxxxxxxxxxxxxxxxxx/ Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Omar Sandoval <osandov@xxxxxx> --- fs/btrfs/inode.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index fec2a78de037..9dc84a88ef0c 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; @@ -5846,7 +5845,7 @@ 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; + 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; @@ -11001,11 +11000,6 @@ 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, -- 2.24.0
