vfs: have chdir retry lookup and call once on 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 a994ccf39b40dc74b49746ac095f5b5231af3f7d..402dfcb6720b7fff3fa7dab47b04c27ec606c0c5 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -394,8 +394,9 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename)
 {
        struct path path;
        int error;
-
-       error = user_path_dir(filename, &path);
+       unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+retry:
+       error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
        if (error)
                goto out;
 
@@ -407,6 +408,10 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename)
 
 dput_and_out:
        path_put(&path);
+       if (retry_estale(error, lookup_flags)) {
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
 out:
        return error;
 }