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nfsd: Protect adding/removing lock owners using client_lock

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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 <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Trond Myklebust 2014-07-29 21:34:35 -04:00 committed by J. Bruce Fields
parent 7ffb588086
commit c58c6610ec
1 changed files with 61 additions and 8 deletions
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69
fs/nfsd/nfs4state.c
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@ -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;
}