From 7ffb588086e941aa0a46a33e2bf2bf3c0963ed98 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 29 Jul 2014 21:34:34 -0400 Subject: [PATCH] nfsd: Protect adding/removing open state 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_open_stateowner checks the hashtable under the client_lock before adding a new element. Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4state.c | 118 ++++++++++++++++++++++++++++++-------------- 1 file changed, 80 insertions(+), 38 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 6d26d26751f5..c4bb7f2b29d9 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -239,6 +239,53 @@ static void nfsd4_put_session(struct nfsd4_session *ses) spin_unlock(&nn->client_lock); } +static int +same_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner, + clientid_t *clid) +{ + return (sop->so_owner.len == owner->len) && + 0 == memcmp(sop->so_owner.data, owner->data, owner->len) && + (sop->so_client->cl_clientid.cl_id == clid->cl_id); +} + +static struct nfs4_openowner * +find_openstateowner_str_locked(unsigned int hashval, struct nfsd4_open *open, + bool sessions, struct nfsd_net *nn) +{ + struct nfs4_stateowner *so; + struct nfs4_openowner *oo; + struct nfs4_client *clp; + + lockdep_assert_held(&nn->client_lock); + + list_for_each_entry(so, &nn->ownerstr_hashtbl[hashval], so_strhash) { + if (!so->so_is_open_owner) + continue; + if (same_owner_str(so, &open->op_owner, &open->op_clientid)) { + oo = openowner(so); + clp = oo->oo_owner.so_client; + if ((bool)clp->cl_minorversion != sessions) + break; + renew_client_locked(clp); + atomic_inc(&so->so_count); + return oo; + } + } + return NULL; +} + +static struct nfs4_openowner * +find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open, + bool sessions, struct nfsd_net *nn) +{ + struct nfs4_openowner *oo; + + spin_lock(&nn->client_lock); + oo = find_openstateowner_str_locked(hashval, open, sessions, nn); + spin_unlock(&nn->client_lock); + return oo; +} + static inline u32 opaque_hashval(const void *ptr, int nbytes) @@ -1005,8 +1052,13 @@ static void release_open_stateid(struct nfs4_ol_stateid *stp) nfs4_put_stid(&stp->st_stid); } -static void unhash_openowner(struct nfs4_openowner *oo) +static void unhash_openowner_locked(struct nfs4_openowner *oo) { + struct nfsd_net *nn = net_generic(oo->oo_owner.so_client->net, + nfsd_net_id); + + lockdep_assert_held(&nn->client_lock); + list_del_init(&oo->oo_owner.so_strhash); list_del_init(&oo->oo_perclient); } @@ -1025,18 +1077,29 @@ static void release_last_closed_stateid(struct nfs4_openowner *oo) static void release_openowner_stateids(struct nfs4_openowner *oo) { struct nfs4_ol_stateid *stp; + struct nfsd_net *nn = net_generic(oo->oo_owner.so_client->net, + nfsd_net_id); + + lockdep_assert_held(&nn->client_lock); while (!list_empty(&oo->oo_owner.so_stateids)) { stp = list_first_entry(&oo->oo_owner.so_stateids, struct nfs4_ol_stateid, st_perstateowner); + spin_unlock(&nn->client_lock); release_open_stateid(stp); + spin_lock(&nn->client_lock); } } static void release_openowner(struct nfs4_openowner *oo) { - unhash_openowner(oo); + struct nfsd_net *nn = net_generic(oo->oo_owner.so_client->net, + nfsd_net_id); + + spin_lock(&nn->client_lock); + unhash_openowner_locked(oo); release_openowner_stateids(oo); + spin_unlock(&nn->client_lock); release_last_closed_stateid(oo); nfs4_put_stateowner(&oo->oo_owner); } @@ -3004,8 +3067,11 @@ static void hash_openowner(struct nfs4_openowner *oo, struct nfs4_client *clp, u static void nfs4_unhash_openowner(struct nfs4_stateowner *so) { struct nfs4_openowner *oo = openowner(so); + struct nfsd_net *nn = net_generic(so->so_client->net, nfsd_net_id); - unhash_openowner(oo); + spin_lock(&nn->client_lock); + unhash_openowner_locked(oo); + spin_unlock(&nn->client_lock); } static void nfs4_free_openowner(struct nfs4_stateowner *so) @@ -3025,7 +3091,8 @@ alloc_init_open_stateowner(unsigned int strhashval, struct nfsd4_open *open, struct nfsd4_compound_state *cstate) { struct nfs4_client *clp = cstate->clp; - struct nfs4_openowner *oo; + struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id); + struct nfs4_openowner *oo, *ret; oo = alloc_stateowner(openowner_slab, &open->op_owner, clp); if (!oo) @@ -3039,7 +3106,15 @@ alloc_init_open_stateowner(unsigned int strhashval, struct nfsd4_open *open, oo->oo_time = 0; oo->oo_last_closed_stid = NULL; INIT_LIST_HEAD(&oo->oo_close_lru); - hash_openowner(oo, clp, strhashval); + spin_lock(&nn->client_lock); + ret = find_openstateowner_str_locked(strhashval, + open, clp->cl_minorversion, nn); + if (ret == NULL) { + hash_openowner(oo, clp, strhashval); + ret = oo; + } else + nfs4_free_openowner(&oo->oo_owner); + spin_unlock(&nn->client_lock); return oo; } @@ -3100,39 +3175,6 @@ move_to_close_lru(struct nfs4_ol_stateid *s, struct net *net) oo->oo_time = get_seconds(); } -static int -same_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner, - clientid_t *clid) -{ - return (sop->so_owner.len == owner->len) && - 0 == memcmp(sop->so_owner.data, owner->data, owner->len) && - (sop->so_client->cl_clientid.cl_id == clid->cl_id); -} - -static struct nfs4_openowner * -find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open, - bool sessions, struct nfsd_net *nn) -{ - struct nfs4_stateowner *so; - struct nfs4_openowner *oo; - struct nfs4_client *clp; - - list_for_each_entry(so, &nn->ownerstr_hashtbl[hashval], so_strhash) { - if (!so->so_is_open_owner) - continue; - if (same_owner_str(so, &open->op_owner, &open->op_clientid)) { - oo = openowner(so); - clp = oo->oo_owner.so_client; - if ((bool)clp->cl_minorversion != sessions) - return NULL; - renew_client(oo->oo_owner.so_client); - atomic_inc(&oo->oo_owner.so_count); - return oo; - } - } - return NULL; -} - /* search file_hashtbl[] for file */ static struct nfs4_file * find_file_locked(struct knfsd_fh *fh) -- 2.20.1