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>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/namei.c b/fs/namei.c
index b06a111591a8..6868699272bf 100644
--- 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);