ovl: fix encoding fid for lower only root

commit 004b8d1491 upstream.

ovl_check_encode_origin() should return a positive number if the lower
dentry is to be encoded, zero otherwise.  If there's no upper layer at all
(read-only overlay), then it obviously needs to return positive.

This was broken by commit 16aac5ad1f ("ovl: support encoding
non-decodable file handles"), which didn't take the lower-only
configuration into account.

Fix by checking the no-upper-layer case up-front.

Reported-and-tested-by: Youzhong Yang <youzhong@gmail.com>
Closes: https://lore.kernel.org/all/CADpNCvaBimi+zCYfRJHvCOhMih8OU0rmZkwLuh24MKKroRuT8Q@mail.gmail.com/
Fixes: 16aac5ad1f ("ovl: support encoding non-decodable file handles")
Cc: <stable@vger.kernel.org> # v6.6
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Miklos Szeredi 2024-06-14 09:55:58 +02:00 committed by Greg Kroah-Hartman
parent c1e670b0db
commit c7f5567b5d

View file

@ -181,6 +181,10 @@ static int ovl_check_encode_origin(struct dentry *dentry)
struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
bool decodable = ofs->config.nfs_export;
/* No upper layer? */
if (!ovl_upper_mnt(ofs))
return 1;
/* Lower file handle for non-upper non-decodable */
if (!ovl_dentry_upper(dentry) && !decodable)
return 1;
@ -209,7 +213,7 @@ static int ovl_check_encode_origin(struct dentry *dentry)
* ovl_connect_layer() will try to make origin's layer "connected" by
* copying up a "connectable" ancestor.
*/
if (d_is_dir(dentry) && ovl_upper_mnt(ofs) && decodable)
if (d_is_dir(dentry) && decodable)
return ovl_connect_layer(dentry);
/* Lower file handle for indexed and non-upper dir/non-dir */