NFSv4: Fix dropped lock for racing OPEN and delegation return
commit 1cbc11aa upstream. Commmit f5ea1613 ("NFSv4: Retry LOCK on OLD_STATEID during delegation return") attempted to solve this problem by using nfs4's generic async error handling, but introduced a regression where v4.0 lock recovery would hang. The additional complexity introduced by overloading that error handling is not necessary for this case. This patch expects that commit to be reverted. The problem as originally explained in the above commit is: There's a small window where a LOCK sent during a delegation return can race with another OPEN on client, but the open stateid has not yet been updated. In this case, the client doesn't handle the OLD_STATEID error from the server and will lose this lock, emitting: "NFS: nfs4_handle_delegation_recall_error: unhandled error -10024". Fix this by using the old_stateid refresh helpers if the server replies with OLD_STATEID. Suggested-by: Trond Myklebust <trondmy@hammerspace.com> Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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