Btrfs: allow treeid==0 in the inode lookup ioctl

When a root id of 0 is sent to the inode lookup ioctl, it will
use the root of the file we're ioctling and pass the root id
back to userland along with the results.

This allows userland to do searches based on that root later on.


Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index fd757f57695..1e462de6556 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1215,6 +1215,9 @@ static noinline int btrfs_ioctl_ino_lookup(struct file *file,
 	}
 	inode = fdentry(file)->d_inode;
 
+	if (args->treeid == 0)
+		args->treeid = BTRFS_I(inode)->root->root_key.objectid;
+
 	ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
 					args->treeid, args->objectid,
 					args->name);