On Sun, Aug 07, 2016 at 02:53:07PM -0400, Chuck Lever wrote: > When running LTP's nfslock01 test, the Linux client can send a LOCK > and a FREE_STATEID request at the same time. The LOCK uses the same > lockowner as the stateid sent in the FREE_STATEID request. > > The outcome is: > > Frame 115025 C FREE_STATEID stateid 2/A > Frame 115026 C LOCK offset 672128 len 64 > Frame 115029 R FREE_STATEID NFS4_OK > Frame 115030 R LOCK stateid 3/A > Frame 115034 C WRITE stateid 0/A offset 672128 len 64 > Frame 115038 R WRITE NFS4ERR_BAD_STATEID > > In other words, the server returns stateid A in a successful LOCK > reply, but it has already released it. Subsequent uses of the > stateid fail. > > To address this, protect the generation check in nfsd4_free_stateid > with the st_mutex. This should guarantee that only one of two > outcomes occurs: either LOCK returns a fresh valid stateid, or > FREE_STATEID returns NFS4ERR_LOCKS_HELD. > > Reported-by: Alexey Kodanev <alexey.kodanev@xxxxxxxxxx> > Fix-suggested-by: Jeff Layton <jlayton@xxxxxxxxxx> > Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> > --- > fs/nfsd/nfs4state.c | 19 ++++++++++++------- > 1 file changed, 12 insertions(+), 7 deletions(-) > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index b921123..07dc1aa 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -4911,19 +4911,20 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, > ret = nfserr_locks_held; > break; > case NFS4_LOCK_STID: > + atomic_inc(&s->sc_count); > + spin_unlock(&cl->cl_lock); > + stp = openlockstateid(s); > + mutex_lock(&stp->st_mutex); > ret = check_stateid_generation(stateid, &s->sc_stateid, 1); > if (ret) > - break; > - stp = openlockstateid(s); > + goto out_mutex_unlock; > ret = nfserr_locks_held; > if (check_for_locks(stp->st_stid.sc_file, > lockowner(stp->st_stateowner))) > - break; > - WARN_ON(!unhash_lock_stateid(stp)); > - spin_unlock(&cl->cl_lock); > - nfs4_put_stid(s); > + goto out_mutex_unlock; > + release_lock_stateid(stp); > ret = nfs_ok; > - goto out; > + goto out_mutex_unlock; It would be nice to split the non-trivial cases (at least NFS4_LOCK_STID and NFS4_REVOKED_DELEG_STID) into separate helpers here as a follow on patch.. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
