cachefiles: fix error return code in cachefiles_ondemand_copen()

The cache_size field of copen is specified by the user daemon.
If cache_size < 0, then the OPEN request is expected to fail,
while copen itself shall succeed. However, returning 0 is indeed
unexpected when cache_size is an invalid error code.

Fix this by returning error when cache_size is an invalid error code.

Changes
=======
v4: update the code suggested by Dan
v3: update the commit log suggested by Jingbo.

Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Sun Ke <[email protected]>
Suggested-by: Jeffle Xu <[email protected]>
Suggested-by: Dan Carpenter <[email protected]>
Signed-off-by: David Howells <[email protected]>
Reviewed-by: Gao Xiang <[email protected]>
Reviewed-by: Jingbo Xu <[email protected]>
Reviewed-by: Dan Carpenter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]/ # v2
Link: https://lore.kernel.org/r/[email protected]/ # v3
Link: https://lore.kernel.org/r/[email protected]/ # v4

1 files changed, 7 insertions, 3 deletions

diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index 1fee702d5529..7e1586bd5cf3 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -158,9 +158,13 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args)
 
 	/* fail OPEN request if daemon reports an error */
 	if (size < 0) {
-		if (!IS_ERR_VALUE(size))
-			size = -EINVAL;
-		req->error = size;
+		if (!IS_ERR_VALUE(size)) {
+			req->error = -EINVAL;
+			ret = -EINVAL;
+		} else {
+			req->error = size;
+			ret = 0;
+		}
 		goto out;
 	}