1 files changed, 34 insertions, 0 deletions

diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c
index ff14b032459b..a824050be807 100644
--- a/fs/nfs/fscache-index.c
+++ b/fs/nfs/fscache-index.c
@@ -112,3 +112,37 @@ const struct fscache_cookie_def nfs_fscache_server_index_def = {
         .type           = FSCACHE_COOKIE_TYPE_INDEX,
         .get_key        = nfs_server_get_key,
 };
+
+/*
+ * Generate a key to describe a superblock key in the main NFS index
+ */
+static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
+                                  void *buffer, uint16_t bufmax)
+{
+        const struct nfs_fscache_key *key;
+        const struct nfs_server *nfss = cookie_netfs_data;
+        uint16_t len;
+
+        key = nfss->fscache_key;
+        len = sizeof(key->key) + key->key.uniq_len;
+        if (len > bufmax) {
+                len = 0;
+        } else {
+                memcpy(buffer, &key->key, sizeof(key->key));
+                memcpy(buffer + sizeof(key->key),
+                       key->key.uniquifier, key->key.uniq_len);
+        }
+
+        return len;
+}
+
+/*
+ * Define the superblock object for FS-Cache.  This is used to describe a
+ * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
+ * parameters that might cause a separate superblock.
+ */
+const struct fscache_cookie_def nfs_fscache_super_index_def = {
+        .name           = "NFS.super",
+        .type           = FSCACHE_COOKIE_TYPE_INDEX,
+        .get_key        = nfs_super_get_key,
+};