1 files changed, 116 insertions, 0 deletions

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index c3f056f89477..ab2de2c92b21 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -23,6 +23,9 @@
 
 #define NFSDBG_FACILITY		NFSDBG_FSCACHE
 
+static struct rb_root nfs_fscache_keys = RB_ROOT;
+static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
+
 /*
  * Get the per-client index cookie for an NFS client if the appropriate mount
  * flag was set
@@ -50,3 +53,116 @@ void nfs_fscache_release_client_cookie(struct nfs_client *clp)
 	fscache_relinquish_cookie(clp->fscache, 0);
 	clp->fscache = NULL;
 }
+
+/*
+ * Get the cache cookie for an NFS superblock.  We have to handle
+ * uniquification here because the cache doesn't do it for us.
+ */
+void nfs_fscache_get_super_cookie(struct super_block *sb,
+				  struct nfs_parsed_mount_data *data)
+{
+	struct nfs_fscache_key *key, *xkey;
+	struct nfs_server *nfss = NFS_SB(sb);
+	struct rb_node **p, *parent;
+	const char *uniq = data->fscache_uniq ?: "";
+	int diff, ulen;
+
+	ulen = strlen(uniq);
+	key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
+	if (!key)
+		return;
+
+	key->nfs_client = nfss->nfs_client;
+	key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
+	key->key.nfs_server.flags = nfss->flags;
+	key->key.nfs_server.rsize = nfss->rsize;
+	key->key.nfs_server.wsize = nfss->wsize;
+	key->key.nfs_server.acregmin = nfss->acregmin;
+	key->key.nfs_server.acregmax = nfss->acregmax;
+	key->key.nfs_server.acdirmin = nfss->acdirmin;
+	key->key.nfs_server.acdirmax = nfss->acdirmax;
+	key->key.nfs_server.fsid = nfss->fsid;
+	key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
+
+	key->key.uniq_len = ulen;
+	memcpy(key->key.uniquifier, uniq, ulen);
+
+	spin_lock(&nfs_fscache_keys_lock);
+	p = &nfs_fscache_keys.rb_node;
+	parent = NULL;
+	while (*p) {
+		parent = *p;
+		xkey = rb_entry(parent, struct nfs_fscache_key, node);
+
+		if (key->nfs_client < xkey->nfs_client)
+			goto go_left;
+		if (key->nfs_client > xkey->nfs_client)
+			goto go_right;
+
+		diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
+		if (diff < 0)
+			goto go_left;
+		if (diff > 0)
+			goto go_right;
+
+		if (key->key.uniq_len == 0)
+			goto non_unique;
+		diff = memcmp(key->key.uniquifier,
+			      xkey->key.uniquifier,
+			      key->key.uniq_len);
+		if (diff < 0)
+			goto go_left;
+		if (diff > 0)
+			goto go_right;
+		goto non_unique;
+
+	go_left:
+		p = &(*p)->rb_left;
+		continue;
+	go_right:
+		p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&key->node, parent, p);
+	rb_insert_color(&key->node, &nfs_fscache_keys);
+	spin_unlock(&nfs_fscache_keys_lock);
+	nfss->fscache_key = key;
+
+	/* create a cache index for looking up filehandles */
+	nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
+					       &nfs_fscache_super_index_def,
+					       nfss);
+	dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
+		 nfss, nfss->fscache);
+	return;
+
+non_unique:
+	spin_unlock(&nfs_fscache_keys_lock);
+	kfree(key);
+	nfss->fscache_key = NULL;
+	nfss->fscache = NULL;
+	printk(KERN_WARNING "NFS:"
+	       " Cache request denied due to non-unique superblock keys\n");
+}
+
+/*
+ * release a per-superblock cookie
+ */
+void nfs_fscache_release_super_cookie(struct super_block *sb)
+{
+	struct nfs_server *nfss = NFS_SB(sb);
+
+	dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
+		 nfss, nfss->fscache);
+
+	fscache_relinquish_cookie(nfss->fscache, 0);
+	nfss->fscache = NULL;
+
+	if (nfss->fscache_key) {
+		spin_lock(&nfs_fscache_keys_lock);
+		rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
+		spin_unlock(&nfs_fscache_keys_lock);
+		kfree(nfss->fscache_key);
+		nfss->fscache_key = NULL;
+	}
+}