NFSv4: Reduce the footprint of the idmapper

Instead of pre-allocating the storage for all the strings, we can
significantly reduce the size of that table by doing the allocation
when we do the downcall.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 13 insertions, 3 deletions

diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index 5a5566fa1619..fff79481218c 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -362,7 +362,7 @@ struct idmap_hashent {
         unsigned long           ih_expires;
         __u32                   ih_id;
         size_t                  ih_namelen;
-        char                    ih_name[IDMAP_NAMESZ];
+        const char              *ih_name;
 };
 
 struct idmap_hashtable {
@@ -482,12 +482,17 @@ void
 nfs_idmap_delete(struct nfs_client *clp)
 {
         struct idmap *idmap = clp->cl_idmap;
+        int i;
 
         if (!idmap)
                 return;
         nfs_idmap_unregister(clp, idmap->idmap_pipe);
         rpc_destroy_pipe_data(idmap->idmap_pipe);
         clp->cl_idmap = NULL;
+        for (i = 0; i < ARRAY_SIZE(idmap->idmap_user_hash.h_entries); i++)
+                kfree(idmap->idmap_user_hash.h_entries[i].ih_name);
+        for (i = 0; i < ARRAY_SIZE(idmap->idmap_group_hash.h_entries); i++)
+                kfree(idmap->idmap_group_hash.h_entries[i].ih_name);
         kfree(idmap);
 }
 
@@ -634,9 +639,14 @@ static void
 idmap_update_entry(struct idmap_hashent *he, const char *name,
                 size_t namelen, __u32 id)
 {
+        char *str = kmalloc(namelen + 1, GFP_KERNEL);
+        if (str == NULL)
+                return;
+        kfree(he->ih_name);
         he->ih_id = id;
-        memcpy(he->ih_name, name, namelen);
-        he->ih_name[namelen] = '\0';
+        memcpy(str, name, namelen);
+        str[namelen] = '\0';
+        he->ih_name = str;
         he->ih_namelen = namelen;
         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 }