vfs: have faccessat retry once on an ESTALE error

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

diff --git a/fs/open.c b/fs/open.c
index 07449b9..a994ccf 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -316,6 +316,7 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
        struct path path;
        struct inode *inode;
        int res;
+       unsigned int lookup_flags = LOOKUP_FOLLOW;
 
        if (mode & ~S_IRWXO)    /* where's F_OK, X_OK, W_OK, R_OK? */
                return -EINVAL;
@@ -338,8 +339,8 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
        }
 
        old_cred = override_creds(override_cred);
-
-       res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
+retry:
+       res = user_path_at(dfd, filename, lookup_flags, &path);
        if (res)
                goto out;
 
@@ -374,6 +375,10 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
 
 out_path_release:
        path_put(&path);
+       if (retry_estale(res, lookup_flags)) {
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
 out:
        revert_creds(old_cred);
        put_cred(override_cred);