From 1af71cc8014e78e975ca47929c957228019a579b Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 29 Jul 2014 21:34:14 -0400 Subject: [PATCH] nfsd: ensure atomicity in nfsd4_free_stateid and nfsd4_validate_stateid 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 Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4state.c | 71 +++++++++++++++++++++++---------------------- 1 file changed, 36 insertions(+), 35 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 59d44873b68b..f4c7bf96c9fd 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1688,17 +1688,6 @@ 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) { @@ -4098,10 +4087,10 @@ 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]; @@ -4109,34 +4098,42 @@ 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 @@ -4287,34 +4284,38 @@ 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 - ret = nfserr_locks_held; + break; + ret = nfserr_locks_held; break; + case NFS4_LOCK_STID: + ret = check_stateid_generation(stateid, &s->sc_stateid, 1); + if (ret) + break; + spin_unlock(&cl->cl_lock); + ret = nfsd4_free_lock_stateid(openlockstateid(s)); + goto out; case NFS4_REVOKED_DELEG_STID: dp = delegstateid(s); - spin_lock(&cl->cl_lock); list_del_init(&dp->dl_recall_lru); spin_unlock(&cl->cl_lock); nfs4_put_stid(s); 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; -- 2.34.1