[01/40] nfsd4: use cl_lock to synchronize all stateid idr calls

Commit Message

Jeff Layton July 21, 2014, 3:02 p.m. UTC

From: Benny Halevy <[e-mail]>

Currently, this is serialized by the client_mutex, which is slated for
removal. Add finer-grained locking here.

Signed-off-by: Benny Halevy <[e-mail]>
---
 fs/nfsd/nfs4state.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

Comments

Christoph Hellwig July 27, 2014, 1:21 p.m. UTC | #1

>  static void nfs4_free_stid(struct kmem_cache *slab, struct nfs4_stid *s)
> @@ -1421,7 +1426,9 @@ free_client(struct nfs4_client *clp)
>  	rpc_destroy_wait_queue(&clp->cl_cb_waitq);
>  	free_svc_cred(&clp->cl_cred);
>  	kfree(clp->cl_name.data);
> +	spin_lock(&clp->cl_lock);
>  	idr_destroy(&clp->cl_stateids);
> +	spin_unlock(&clp->cl_lock);
>  	kfree(clp);
>  }

No need for  locking around idr_destroy - the client structure better
be dead by the time we free it.

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Patch

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3946a5a9459c..3e55df0d7504 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -455,7 +455,6 @@  static void nfs4_file_put_access(struct nfs4_file *fp, u32 access)
 static struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct
 kmem_cache *slab)
 {
-	struct idr *stateids = &cl->cl_stateids;
 	struct nfs4_stid *stid;
 	int new_id;
 
@@ -463,7 +462,11 @@  kmem_cache *slab)
 	if (!stid)
 		return NULL;
 
-	new_id = idr_alloc_cyclic(stateids, stid, 0, 0, GFP_KERNEL);
+	idr_preload(GFP_KERNEL);
+	spin_lock(&cl->cl_lock);
+	new_id = idr_alloc_cyclic(&cl->cl_stateids, stid, 0, 0, GFP_NOWAIT);
+	spin_unlock(&cl->cl_lock);
+	idr_preload_end();
 	if (new_id < 0)
 		goto out_free;
 	stid->sc_client = cl;
@@ -603,9 +606,11 @@  out_dec:
 
 static void remove_stid(struct nfs4_stid *s)
 {
-	struct idr *stateids = &s->sc_client->cl_stateids;
+	struct nfs4_client *clp = s->sc_client;
 
-	idr_remove(stateids, s->sc_stateid.si_opaque.so_id);
+	spin_lock(&clp->cl_lock);
+	idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
+	spin_unlock(&clp->cl_lock);
 }
 
 static void nfs4_free_stid(struct kmem_cache *slab, struct nfs4_stid *s)
@@ -1421,7 +1426,9 @@  free_client(struct nfs4_client *clp)
 	rpc_destroy_wait_queue(&clp->cl_cb_waitq);
 	free_svc_cred(&clp->cl_cred);
 	kfree(clp->cl_name.data);
+	spin_lock(&clp->cl_lock);
 	idr_destroy(&clp->cl_stateids);
+	spin_unlock(&clp->cl_lock);
 	kfree(clp);
 }
 
@@ -1647,7 +1654,9 @@  static struct nfs4_stid *find_stateid(struct nfs4_client *cl, stateid_t *t)
 {
 	struct nfs4_stid *ret;
 
+	spin_lock(&cl->cl_lock);
 	ret = idr_find(&cl->cl_stateids, t->si_opaque.so_id);
+	spin_unlock(&cl->cl_lock);
 	if (!ret || !ret->sc_type)
 		return NULL;
 	return ret;