nfsd: Detect unhashed stids in nfsd4_verify_open_stid()

The state of the stid is guaranteed by 2 locks:
- The nfs4_client 'cl_lock' spinlock
- The nfs4_ol_stateid 'st_mutex' mutex

so it is quite possible for the stid to be unhashed after lookup,
but before calling nfsd4_lock_ol_stateid(). So we do need to check
for a zero value for 'sc_type' in nfsd4_verify_open_stid().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Checuk Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Fixes: 659aefb68eca "nfsd: Ensure we don't recognise lock stateids..."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b29b5a185a2cb444f95fce2685381755d05d9429..5a75135f5f53b45752eca08d08c79a8f55292fa2 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3590,6 +3590,7 @@ nfsd4_verify_open_stid(struct nfs4_stid *s)
        switch (s->sc_type) {
        default:
                break;
+       case 0:
        case NFS4_CLOSED_STID:
        case NFS4_CLOSED_DELEG_STID:
                ret = nfserr_bad_stateid;