6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bernd Schubert <bschubert@xxxxxxx>
commit 3ab394b363c5fd14b231e335fb6746ddfb93aaaa upstream.
Current design and handling of passthrough is without fuse
caching and with that FUSE_WRITEBACK_CACHE is conflicting.
Fixes: 7dc4e97a4f9a ("fuse: introduce FUSE_PASSTHROUGH capability")
Cc: stable@xxxxxxxxxx # v6.9
Signed-off-by: Bernd Schubert <bschubert@xxxxxxx>
Acked-by: Amir Goldstein <amir73il@xxxxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/fuse/inode.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1336,11 +1336,16 @@ static void process_init_reply(struct fu
* on a stacked fs (e.g. overlayfs) themselves and with
* max_stack_depth == 1, FUSE fs can be stacked as the
* underlying fs of a stacked fs (e.g. overlayfs).
+ *
+ * Also don't allow the combination of FUSE_PASSTHROUGH
+ * and FUSE_WRITEBACK_CACHE, current design doesn't handle
+ * them together.
*/
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) &&
(flags & FUSE_PASSTHROUGH) &&
arg->max_stack_depth > 0 &&
- arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH) {
+ arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH &&
+ !(flags & FUSE_WRITEBACK_CACHE)) {
fc->passthrough = 1;
fc->max_stack_depth = arg->max_stack_depth;
fm->sb->s_stack_depth = arg->max_stack_depth;
