nfsd4: use cl_lock to synchronize all stateid idr calls

Currently, this is serialized by the client_mutex, which is slated for
removal. Add finer-grained locking here. Also, do some cleanup around
find_stateid to prepare for taking references.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Benny Halevy <bhalevy@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 30 insertions, 11 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 344cd1ac3f67..bb37cc4dd573 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -467,7 +467,6 @@ 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;
 
@@ -475,7 +474,11 @@ static struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl,
         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;
@@ -635,9 +638,12 @@ nfs4_put_stid(struct nfs4_stid *s)
         struct nfs4_file *fp = s->sc_file;
         struct nfs4_client *clp = s->sc_client;
 
-        if (!atomic_dec_and_test(&s->sc_count))
+        might_lock(&clp->cl_lock);
+
+        if (!atomic_dec_and_lock(&s->sc_count, &clp->cl_lock))
                 return;
         idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
+        spin_unlock(&clp->cl_lock);
         s->sc_free(s);
         if (fp)
                 put_nfs4_file(fp);
@@ -1652,7 +1658,8 @@ static void gen_confirm(struct nfs4_client *clp)
         memcpy(clp->cl_confirm.data, verf, sizeof(clp->cl_confirm.data));
 }
 
-static struct nfs4_stid *find_stateid(struct nfs4_client *cl, stateid_t *t)
+static struct nfs4_stid *
+find_stateid_locked(struct nfs4_client *cl, stateid_t *t)
 {
         struct nfs4_stid *ret;
 
@@ -1662,16 +1669,28 @@ static struct nfs4_stid *find_stateid(struct nfs4_client *cl, stateid_t *t)
         return ret;
 }
 
-static struct nfs4_stid *find_stateid_by_type(struct nfs4_client *cl, stateid_t *t, char typemask)
+static struct nfs4_stid *
+find_stateid(struct nfs4_client *cl, stateid_t *t)
+{
+        struct nfs4_stid *ret;
+
+        spin_lock(&cl->cl_lock);
+        ret = find_stateid_locked(cl, t);
+        spin_unlock(&cl->cl_lock);
+        return ret;
+}
+
+static struct nfs4_stid *
+find_stateid_by_type(struct nfs4_client *cl, stateid_t *t, char typemask)
 {
         struct nfs4_stid *s;
 
-        s = find_stateid(cl, t);
-        if (!s)
-                return NULL;
-        if (typemask & s->sc_type)
-                return s;
-        return NULL;
+        spin_lock(&cl->cl_lock);
+        s = find_stateid_locked(cl, t);
+        if (s != NULL && !(typemask & s->sc_type))
+                s = NULL;
+        spin_unlock(&cl->cl_lock);
+        return s;
 }
 
 static struct nfs4_client *create_client(struct xdr_netobj name,