NFSv4: Handle NFS4ERR_OLD_STATEID in delegreturn

If the server returns NFS4ERR_OLD_STATEID in response to our delegreturn,
we want to sync to the most recent seqid for the delegation stateid. However
if we are already at the most recent, we have two possibilities:

- an OPEN reply is still outstanding and will return a new seqid
- an earlier OPEN reply was dropped on the floor due to a timeout.

In the latter case, we may end up unable to complete the delegreturn,
so we want to bump the seqid to a value greater than the cached value.
While this may cause us to lose the delegation in the former case,
it should now be safe to assume that the client will replay the OPEN
if necessary in order to get a new valid stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 48f3c6c9672f4a60053c222e541f2261af54a0f8..fe57b2b5314ae1ede602e3102b2321a39c35da17 100644 (file)
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -1252,6 +1252,7 @@ bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
        delegation = rcu_dereference(NFS_I(inode)->delegation);
        if (delegation != NULL &&
            nfs4_stateid_match_other(dst, &delegation->stateid) &&
+           nfs4_stateid_is_newer(&delegation->stateid, dst) &&
            !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
                dst->seqid = delegation->stateid.seqid;
                ret = true;

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index c7e4a9ba842000d62f7103ea8f977fc87f63d6d7..33a8e53e976c67e30ef0b4f094deb1689c0d4f12 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6196,10 +6196,9 @@ static void nfs4_delegreturn_done(struct rpc_task *task, void *calldata)
                task->tk_status = 0;
                break;
        case -NFS4ERR_OLD_STATEID:
-               if (nfs4_refresh_delegation_stateid(&data->stateid, data->inode))
-                       goto out_restart;
-               task->tk_status = 0;
-               break;
+               if (!nfs4_refresh_delegation_stateid(&data->stateid, data->inode))
+                       nfs4_stateid_seqid_inc(&data->stateid);
+               goto out_restart;
        case -NFS4ERR_ACCESS:
                if (data->args.bitmask) {
                        data->args.bitmask = NULL;