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;
+        }
+}