From 03da3169c67f67729d8b52cee4e5689b0a3f94c0 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Fri, 3 Nov 2017 08:00:16 -0400 Subject: [PATCH] nfsd: Fix races with check_stateid_generation() The various functions that call check_stateid_generation() in order to compare a client-supplied stateid with the nfs4_stid state, usually need to atomically check for closed state. Those that perform the check after locking the st_mutex using nfsd4_lock_ol_stateid() should now be OK, but we do want to fix up the others. Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4state.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index da07c24e9372..ecb803d7c966 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4906,6 +4906,18 @@ static __be32 check_stateid_generation(stateid_t *in, stateid_t *ref, bool has_s return nfserr_old_stateid; } +static __be32 nfsd4_stid_check_stateid_generation(stateid_t *in, struct nfs4_stid *s, bool has_session) +{ + __be32 ret; + + spin_lock(&s->sc_lock); + ret = nfsd4_verify_open_stid(s); + if (ret == nfs_ok) + ret = check_stateid_generation(in, &s->sc_stateid, has_session); + spin_unlock(&s->sc_lock); + return ret; +} + static __be32 nfsd4_check_openowner_confirmed(struct nfs4_ol_stateid *ols) { if (ols->st_stateowner->so_is_open_owner && @@ -4934,7 +4946,7 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid) s = find_stateid_locked(cl, stateid); if (!s) goto out_unlock; - status = check_stateid_generation(stateid, &s->sc_stateid, 1); + status = nfsd4_stid_check_stateid_generation(stateid, s, 1); if (status) goto out_unlock; switch (s->sc_type) { @@ -5095,7 +5107,7 @@ nfs4_preprocess_stateid_op(struct svc_rqst *rqstp, &s, nn); if (status) return status; - status = check_stateid_generation(stateid, &s->sc_stateid, + status = nfsd4_stid_check_stateid_generation(stateid, s, nfsd4_has_session(cstate)); if (status) goto out; @@ -5188,6 +5200,7 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, s = find_stateid_locked(cl, stateid); if (!s) goto out_unlock; + spin_lock(&s->sc_lock); switch (s->sc_type) { case NFS4_DELEG_STID: ret = nfserr_locks_held; @@ -5199,11 +5212,13 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, ret = nfserr_locks_held; break; case NFS4_LOCK_STID: + spin_unlock(&s->sc_lock); refcount_inc(&s->sc_count); spin_unlock(&cl->cl_lock); ret = nfsd4_free_lock_stateid(stateid, s); goto out; case NFS4_REVOKED_DELEG_STID: + spin_unlock(&s->sc_lock); dp = delegstateid(s); list_del_init(&dp->dl_recall_lru); spin_unlock(&cl->cl_lock); @@ -5212,6 +5227,7 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, goto out; /* Default falls through and returns nfserr_bad_stateid */ } + spin_unlock(&s->sc_lock); out_unlock: spin_unlock(&cl->cl_lock); out: @@ -5491,7 +5507,7 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, if (status) goto out; dp = delegstateid(s); - status = check_stateid_generation(stateid, &dp->dl_stid.sc_stateid, nfsd4_has_session(cstate)); + status = nfsd4_stid_check_stateid_generation(stateid, &dp->dl_stid, nfsd4_has_session(cstate)); if (status) goto put_stateid;