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>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index fd757f5769562cb33ca68c695a361e09cb916c2b..1e462de6556e21ea37802fab6588f2e65177bfa5 100644 (file)
--- 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);