On Tue, Jul 29, 2014 at 09:34:35PM -0400, Jeff Layton wrote:
> 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_lock_stateowner checks the hashtable under the
> client_lock before adding a new element.
Not worth respinning any patches for this, but "alloc_init_..." was
never my favorite naming scheme, and isn't so accurate at this point.
"find_or_create_..." is a little cumbersome too, but maybe it'd do.
--b.
>
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 61 insertions(+), 8 deletions(-)
>
> 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;
> }
> --
> 1.9.3
>
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