vfs: fix user_statfs to 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, 8 insertions, 1 deletions

diff --git a/fs/statfs.c b/fs/statfs.c
index f8e832e6f0a2..c219e733f553 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -77,10 +77,17 @@ EXPORT_SYMBOL(vfs_statfs);
 int user_statfs(const char __user *pathname, struct kstatfs *st)
 {
         struct path path;
-        int error = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
+        int error;
+        unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT;
+retry:
+        error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
         if (!error) {
                 error = vfs_statfs(&path, st);
                 path_put(&path);
+                if (retry_estale(error, lookup_flags)) {
+                        lookup_flags |= LOOKUP_REVAL;
+                        goto retry;
+                }
         }
         return error;
 }