From: Trond Myklebust Date: Wed, 30 Jul 2014 01:34:35 +0000 (-0400) Subject: nfsd: Protect adding/removing lock owners using client_lock X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c58c6610ec248134b0b0ede2ac80859bf1cefa29;p=linux-beck.git nfsd: Protect adding/removing lock owners using client_lock Once we remove client mutex protection, we'll need to ensure that stateowner lookup and creation are atomic between concurrent compounds. Ensure that alloc_init_lock_stateowner checks the hashtable under the client_lock before adding a new element. Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields --- diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index c4bb7f2b29d9..7c15918d20f0 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1000,26 +1000,42 @@ static void release_lock_stateid(struct nfs4_ol_stateid *stp) nfs4_put_stid(&stp->st_stid); } -static void unhash_lockowner(struct nfs4_lockowner *lo) +static void unhash_lockowner_locked(struct nfs4_lockowner *lo) { + struct nfsd_net *nn = net_generic(lo->lo_owner.so_client->net, + nfsd_net_id); + + lockdep_assert_held(&nn->client_lock); + list_del_init(&lo->lo_owner.so_strhash); } static void release_lockowner_stateids(struct nfs4_lockowner *lo) { + struct nfsd_net *nn = net_generic(lo->lo_owner.so_client->net, + nfsd_net_id); struct nfs4_ol_stateid *stp; + lockdep_assert_held(&nn->client_lock); + while (!list_empty(&lo->lo_owner.so_stateids)) { stp = list_first_entry(&lo->lo_owner.so_stateids, struct nfs4_ol_stateid, st_perstateowner); + spin_unlock(&nn->client_lock); release_lock_stateid(stp); + spin_lock(&nn->client_lock); } } static void release_lockowner(struct nfs4_lockowner *lo) { - unhash_lockowner(lo); + struct nfsd_net *nn = net_generic(lo->lo_owner.so_client->net, + nfsd_net_id); + + spin_lock(&nn->client_lock); + unhash_lockowner_locked(lo); release_lockowner_stateids(lo); + spin_unlock(&nn->client_lock); nfs4_put_stateowner(&lo->lo_owner); } @@ -4801,7 +4817,7 @@ nevermind: } static struct nfs4_lockowner * -find_lockowner_str(clientid_t *clid, struct xdr_netobj *owner, +find_lockowner_str_locked(clientid_t *clid, struct xdr_netobj *owner, struct nfsd_net *nn) { unsigned int strhashval = ownerstr_hashval(clid->cl_id, owner); @@ -4818,9 +4834,25 @@ find_lockowner_str(clientid_t *clid, struct xdr_netobj *owner, return NULL; } +static struct nfs4_lockowner * +find_lockowner_str(clientid_t *clid, struct xdr_netobj *owner, + struct nfsd_net *nn) +{ + struct nfs4_lockowner *lo; + + spin_lock(&nn->client_lock); + lo = find_lockowner_str_locked(clid, owner, nn); + spin_unlock(&nn->client_lock); + return lo; +} + static void nfs4_unhash_lockowner(struct nfs4_stateowner *sop) { - unhash_lockowner(lockowner(sop)); + struct nfsd_net *nn = net_generic(sop->so_client->net, nfsd_net_id); + + spin_lock(&nn->client_lock); + unhash_lockowner_locked(lockowner(sop)); + spin_unlock(&nn->client_lock); } static void nfs4_free_lockowner(struct nfs4_stateowner *sop) @@ -4843,9 +4875,12 @@ static const struct nfs4_stateowner_operations lockowner_ops = { * strhashval = ownerstr_hashval */ static struct nfs4_lockowner * -alloc_init_lock_stateowner(unsigned int strhashval, struct nfs4_client *clp, struct nfs4_ol_stateid *open_stp, struct nfsd4_lock *lock) { - struct nfs4_lockowner *lo; +alloc_init_lock_stateowner(unsigned int strhashval, struct nfs4_client *clp, + struct nfs4_ol_stateid *open_stp, + struct nfsd4_lock *lock) +{ struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id); + struct nfs4_lockowner *lo, *ret; lo = alloc_stateowner(lockowner_slab, &lock->lk_new_owner, clp); if (!lo) @@ -4854,7 +4889,16 @@ alloc_init_lock_stateowner(unsigned int strhashval, struct nfs4_client *clp, str lo->lo_owner.so_is_open_owner = 0; lo->lo_owner.so_seqid = lock->lk_new_lock_seqid; lo->lo_owner.so_ops = &lockowner_ops; - list_add(&lo->lo_owner.so_strhash, &nn->ownerstr_hashtbl[strhashval]); + spin_lock(&nn->client_lock); + ret = find_lockowner_str_locked(&clp->cl_clientid, + &lock->lk_new_owner, nn); + if (ret == NULL) { + list_add(&lo->lo_owner.so_strhash, + &nn->ownerstr_hashtbl[strhashval]); + ret = lo; + } else + nfs4_free_lockowner(&lo->lo_owner); + spin_unlock(&nn->client_lock); return lo; } @@ -5395,6 +5439,7 @@ nfsd4_release_lockowner(struct svc_rqst *rqstp, unsigned int hashval = ownerstr_hashval(clid->cl_id, owner); __be32 status; struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); + struct nfs4_client *clp; dprintk("nfsd4_release_lockowner clientid: (%08x/%08x):\n", clid->cl_boot, clid->cl_id); @@ -5408,6 +5453,7 @@ nfsd4_release_lockowner(struct svc_rqst *rqstp, status = nfserr_locks_held; /* Find the matching lock stateowner */ + spin_lock(&nn->client_lock); list_for_each_entry(tmp, &nn->ownerstr_hashtbl[hashval], so_strhash) { if (tmp->so_is_open_owner) continue; @@ -5417,6 +5463,7 @@ nfsd4_release_lockowner(struct svc_rqst *rqstp, break; } } + spin_unlock(&nn->client_lock); /* No matching owner found, maybe a replay? Just declare victory... */ if (!sop) { @@ -5426,16 +5473,22 @@ nfsd4_release_lockowner(struct svc_rqst *rqstp, lo = lockowner(sop); /* see if there are still any locks associated with it */ + clp = cstate->clp; + spin_lock(&clp->cl_lock); list_for_each_entry(stp, &sop->so_stateids, st_perstateowner) { if (check_for_locks(stp->st_stid.sc_file, lo)) { - nfs4_put_stateowner(sop); + spin_unlock(&clp->cl_lock); goto out; } } + spin_unlock(&clp->cl_lock); status = nfs_ok; + sop = NULL; release_lockowner(lo); out: + if (sop) + nfs4_put_stateowner(sop); nfs4_unlock_state(); return status; }