6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
commit 004b8d1491b4bcbb7da1a3206d1e7e66822d47c6 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 16aac5ad1fa9 ("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@xxxxxxxxx>
Closes: https://lore.kernel.org/all/CADpNCvaBimi+zCYfRJHvCOhMih8OU0rmZkwLuh24MKKroRuT8Q@xxxxxxxxxxxxxx/
Fixes: 16aac5ad1fa9 ("ovl: support encoding non-decodable file handles")
Cc: <stable@xxxxxxxxxxxxxxx> # v6.6
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/overlayfs/export.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -186,6 +186,10 @@ static int ovl_check_encode_origin(struc
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;
@@ -214,7 +218,7 @@ static int ovl_check_encode_origin(struc
* 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 */
