From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
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 <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 63 +++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 54 insertions(+), 9 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 296d75d93de4..743a48b6e84a 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -72,6 +72,9 @@ static u64 current_sessionid = 1;
/* forward declarations */
static int check_for_locks(struct nfs4_file *filp, struct nfs4_lockowner *lowner);
static void nfs4_free_generic_stateid(struct nfs4_stid *stid);
+static struct nfs4_openowner *find_openstateowner_str_locked(
+ unsigned int hashval, struct nfsd4_open *open,
+ bool sessions, struct nfsd_net *nn);
static void nfs4_put_stateowner(struct nfs4_stateowner *sop);
/* Locking: */
@@ -1013,8 +1016,13 @@ static void release_open_stateid(struct nfs4_ol_stateid *stp)
put_generic_stateid(stp);
}
-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);
}
@@ -1033,18 +1041,29 @@ 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);
}
@@ -3025,8 +3044,11 @@ 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)
@@ -3042,7 +3064,8 @@ 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)
@@ -3057,7 +3080,15 @@ 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;
}
@@ -3131,13 +3162,15 @@ same_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner,
}
static struct nfs4_openowner *
-find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open,
+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;
@@ -3145,15 +3178,27 @@ find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open,
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);
+ 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;
+}
+
/* search file_hashtbl[] for file */
static struct nfs4_file *
find_file_locked(struct inode *ino)
--
1.9.3
--
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