Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qg0-f54.google.com ([209.85.192.54]:47684 "EHLO mail-qg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753304AbaGHSF5 (ORCPT ); Tue, 8 Jul 2014 14:05:57 -0400 Received: by mail-qg0-f54.google.com with SMTP id q107so5358203qgd.41 for ; Tue, 08 Jul 2014 11:05:57 -0700 (PDT) From: Jeff Layton To: bfields@fieldses.org Cc: linux-nfs@vger.kernel.org Subject: [PATCH v4 060/100] nfsd: close potential race in nfsd4_free_stateid Date: Tue, 8 Jul 2014 14:03:48 -0400 Message-Id: <1404842668-22521-61-git-send-email-jlayton@primarydata.com> In-Reply-To: <1404842668-22521-1-git-send-email-jlayton@primarydata.com> References: <1404842668-22521-1-git-send-email-jlayton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Once we remove the client_mutex, it'll be possible for the sc_type of a lock stateid to change after it's found and checked, but before we can go to destroy it. If that happens, we can end up putting the persistent reference to the stateid more than once, and unhash it more than once. Fix this by unhashing the lock stateid prior to dropping the cl_lock but after finding it. Signed-off-by: Jeff Layton --- fs/nfsd/nfs4state.c | 24 +++++++++--------------- 1 file changed, 9 insertions(+), 15 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index ab248ee470dd..cf90c0078503 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4393,17 +4393,6 @@ unlock_state: return status; } -static __be32 -nfsd4_free_lock_stateid(struct nfs4_ol_stateid *stp) -{ - struct nfs4_lockowner *lo = lockowner(stp->st_stateowner); - - if (check_for_locks(stp->st_stid.sc_file, lo)) - return nfserr_locks_held; - release_lock_stateid(stp); - return nfs_ok; -} - /* * Test if the stateid is valid */ @@ -4430,6 +4419,7 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, stateid_t *stateid = &free_stateid->fr_stateid; struct nfs4_stid *s; struct nfs4_delegation *dp; + struct nfs4_ol_stateid *stp; struct nfs4_client *cl = cstate->session->se_client; __be32 ret = nfserr_bad_stateid; @@ -4447,12 +4437,16 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, ret = check_stateid_generation(stateid, &s->sc_stateid, 1); if (ret) break; - if (s->sc_type != NFS4_LOCK_STID) { - ret = nfserr_locks_held; + stp = openlockstateid(s); + ret = nfserr_locks_held; + if (s->sc_type == NFS4_OPEN_STID || + check_for_locks(s->sc_file, + lockowner(stp->st_stateowner))) break; - } + unhash_lock_stateid(stp); spin_unlock(&cl->cl_lock); - ret = nfsd4_free_lock_stateid(openlockstateid(s)); + put_generic_stateid(stp); + ret = nfs_ok; goto out; case NFS4_REVOKED_DELEG_STID: spin_unlock(&cl->cl_lock); -- 1.9.3