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authorTrond Myklebust <trond.myklebust@primarydata.com>2017-11-03 08:00:16 -0400
committerJ. Bruce Fields <bfields@redhat.com>2017-11-27 16:45:10 -0500
commit03da3169c67f67729d8b52cee4e5689b0a3f94c0 (patch)
tree3298b80d391fa2ac9e082534850ba7d3a925cdc3
parent9271d7e509c1bfc0b9a418caec29ec8d1ac38270 (diff)
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 <trond.myklebust@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
-rw-r--r--fs/nfsd/nfs4state.c22
1 files 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;