vfs: make fchmodat retry once on ESTALE errors

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/open.c b/fs/open.c
index a13a54d3e691..99c3ce5f897b 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -514,11 +514,16 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode
 {
         struct path path;
         int error;
-
-        error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
+        unsigned int lookup_flags = LOOKUP_FOLLOW;
+retry:
+        error = user_path_at(dfd, filename, lookup_flags, &path);
         if (!error) {
                 error = chmod_common(&path, mode);
                 path_put(&path);
+                if (retry_estale(error, lookup_flags)) {
+                        lookup_flags |= LOOKUP_REVAL;
+                        goto retry;
+                }
         }
         return error;
 }