...as always, rename is the messiest of the bunch. We have to track
whether to retry or not via a separate flag since the error handling
is already quite complex.

Signed-off-by: Jeff Layton <jlay...@redhat.com>
---
 fs/namei.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 65e5177..7cf5e91 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3699,12 +3699,25 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char 
__user *, oldname,
        char *from;
        char *to;
        int error;
+       unsigned int try = 0;
+       bool should_retry = false;
+       unsigned int lookup_flags = LOOKUP_PARENT;
 
-       error = user_path_parent(olddfd, oldname, &oldnd, &from);
-       if (error)
+       from = getname(oldname);
+       if (IS_ERR(from))
+               return PTR_ERR(from);
+
+       to = getname(newname);
+       if (IS_ERR(to)) {
+               error = PTR_ERR(to);
                goto exit;
+       }
+retry:
+       error = do_path_lookup(olddfd, from, lookup_flags, &oldnd);
+       if (error)
+               goto exit0;
 
-       error = user_path_parent(newdfd, newname, &newnd, &to);
+       error = do_path_lookup(newdfd, to, lookup_flags, &newnd);
        if (error)
                goto exit1;
 
@@ -3773,13 +3786,21 @@ exit4:
        dput(old_dentry);
 exit3:
        unlock_rename(new_dir, old_dir);
+       if (retry_estale(error, try++))
+               should_retry = true;
 exit2:
        path_put(&newnd.path);
-       putname(to);
 exit1:
        path_put(&oldnd.path);
-       putname(from);
+       if (should_retry) {
+               should_retry = false;
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
+exit0:
+       putname(to);
 exit:
+       putname(from);
        return error;
 }
 
-- 
1.7.11.2

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