Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qc0-f180.google.com ([209.85.216.180]:43476 "EHLO mail-qc0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751511AbaFZTO4 (ORCPT ); Thu, 26 Jun 2014 15:14:56 -0400 Received: by mail-qc0-f180.google.com with SMTP id r5so3541933qcx.39 for ; Thu, 26 Jun 2014 12:14:55 -0700 (PDT) From: Jeff Layton To: bfields@fieldses.org Cc: linux-nfs@vger.kernel.org Subject: [PATCH v2 051/117] nfsd: ensure atomicity in nfsd4_free_stateid and nfsd4_validate_stateid Date: Thu, 26 Jun 2014 15:12:31 -0400 Message-Id: <1403810017-16062-52-git-send-email-jlayton@primarydata.com> In-Reply-To: <1403810017-16062-1-git-send-email-jlayton@primarydata.com> References: <1403810017-16062-1-git-send-email-jlayton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Hold the cl_lock over the bulk of these functions. In addition to ensuring that they aren't freed prematurely, this will also help prevent a potential race that could be introduced later. Once we remove the client_mutex, it'll be possible for FREE_STATEID and CLOSE to race and for both to try to put the "persistent" reference to the stateid. Signed-off-by: Trond Myklebust --- fs/nfsd/nfs4state.c | 67 ++++++++++++++++++++++++++++------------------------- 1 file changed, 35 insertions(+), 32 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index b188a40f6416..42fea991ae0b 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1693,16 +1693,6 @@ find_stateid_locked(struct nfs4_client *cl, stateid_t *t) return ret; } -static struct nfs4_stid *find_stateid(struct nfs4_client *cl, stateid_t *t) -{ - struct nfs4_stid *ret; - - spin_lock(&cl->cl_lock); - ret = find_stateid_locked(cl, t); - spin_unlock(&cl->cl_lock); - return ret; -} - static struct nfs4_stid *find_stateid_by_type(struct nfs4_client *cl, stateid_t *t, char typemask) { struct nfs4_stid *s; @@ -4063,10 +4053,10 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid) { struct nfs4_stid *s; struct nfs4_ol_stateid *ols; - __be32 status; + __be32 status = nfserr_bad_stateid; if (ZERO_STATEID(stateid) || ONE_STATEID(stateid)) - return nfserr_bad_stateid; + return status; /* Client debugging aid. */ if (!same_clid(&stateid->si_opaque.so_clid, &cl->cl_clientid)) { char addr_str[INET6_ADDRSTRLEN]; @@ -4074,34 +4064,42 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid) sizeof(addr_str)); pr_warn_ratelimited("NFSD: client %s testing state ID " "with incorrect client ID\n", addr_str); - return nfserr_bad_stateid; + return status; } - s = find_stateid(cl, stateid); + spin_lock(&cl->cl_lock); + s = find_stateid_locked(cl, stateid); if (!s) - return nfserr_bad_stateid; + goto out_unlock; status = check_stateid_generation(stateid, &s->sc_stateid, 1); if (status) - return status; + goto out_unlock; switch (s->sc_type) { case NFS4_DELEG_STID: - return nfs_ok; + status = nfs_ok; + break; case NFS4_REVOKED_DELEG_STID: - return nfserr_deleg_revoked; + status = nfserr_deleg_revoked; + break; case NFS4_OPEN_STID: case NFS4_LOCK_STID: ols = openlockstateid(s); if (ols->st_stateowner->so_is_open_owner && !(openowner(ols->st_stateowner)->oo_flags & NFS4_OO_CONFIRMED)) - return nfserr_bad_stateid; - return nfs_ok; + status = nfserr_bad_stateid; + else + status = nfs_ok; + break; default: printk("unknown stateid type %x\n", s->sc_type); /* Fallthrough */ case NFS4_CLOSED_STID: case NFS4_CLOSED_DELEG_STID: - return nfserr_bad_stateid; + status = nfserr_bad_stateid; } +out_unlock: + spin_unlock(&cl->cl_lock); + return status; } static __be32 @@ -4252,31 +4250,36 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, __be32 ret = nfserr_bad_stateid; nfs4_lock_state(); - s = find_stateid(cl, stateid); + spin_lock(&cl->cl_lock); + s = find_stateid_locked(cl, stateid); if (!s) - goto out; + goto out_unlock; switch (s->sc_type) { case NFS4_DELEG_STID: ret = nfserr_locks_held; - goto out; + break; case NFS4_OPEN_STID: case NFS4_LOCK_STID: ret = check_stateid_generation(stateid, &s->sc_stateid, 1); if (ret) - goto out; - if (s->sc_type == NFS4_LOCK_STID) - ret = nfsd4_free_lock_stateid(openlockstateid(s)); - else + break; + if (s->sc_type != NFS4_LOCK_STID) { ret = nfserr_locks_held; - break; + break; + } + spin_unlock(&cl->cl_lock); + ret = nfsd4_free_lock_stateid(openlockstateid(s)); + goto out; case NFS4_REVOKED_DELEG_STID: + spin_unlock(&cl->cl_lock); dp = delegstateid(s); destroy_revoked_delegation(dp); ret = nfs_ok; - break; - default: - ret = nfserr_bad_stateid; + goto out; + /* Default falls through and returns nfserr_bad_stateid */ } +out_unlock: + spin_unlock(&cl->cl_lock); out: nfs4_unlock_state(); return ret; -- 1.9.3