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 <sunke32@huawei.com>
Suggested-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220818111935.1683062-1-sunke32@huawei.com/
Link: https://lore.kernel.org/r/20220818125038.2247720-1-sunke32@huawei.com/
Link: https://lore.kernel.org/r/20220826023515.3437469-1-sunke32@huawei.com/

diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index 1fee702d55293e9a25b23fe83dc9bb07dbe96ddb..7e1586bd5cf34e644deb5dd76a238db1f082bfdc 100644 (file)
--- 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;
        }