vfs: fix linkat to retry once on ESTALE errors

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

diff --git a/fs/namei.c b/fs/namei.c
index b06a111591a85ffe6c0f044088370e24bd6569fd..6868699272bf2b82f98657ee495c13ecc71708eb 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3626,12 +3626,13 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
 
        if (flags & AT_SYMLINK_FOLLOW)
                how |= LOOKUP_FOLLOW;
-
+retry:
        error = user_path_at(olddfd, oldname, how, &old_path);
        if (error)
                return error;
 
-       new_dentry = user_path_create(newdfd, newname, &new_path, 0);
+       new_dentry = user_path_create(newdfd, newname, &new_path,
+                                       (how & LOOKUP_REVAL));
        error = PTR_ERR(new_dentry);
        if (IS_ERR(new_dentry))
                goto out;
@@ -3648,6 +3649,10 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
        error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);
 out_dput:
        done_path_create(&new_path, new_dentry);
+       if (retry_estale(error, how)) {
+               how |= LOOKUP_REVAL;
+               goto retry;
+       }
 out:
        path_put(&old_path);