NFSv4: Reduce the footprint of the idmapper

commit d073e9b541e1ac3f52d72c3a153855d9a9ee3278 upstream.

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>
[bwh: Backported to 3.2: adjust context in nfs_idmap_delete()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index 47d1c6f..b8c41c3 100644 (file)
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -318,7 +318,7 @@ 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 {
@@ -382,11 +382,16 @@ void
 nfs_idmap_delete(struct nfs_client *clp)
 {
        struct idmap *idmap = clp->cl_idmap;
+       int i;
 
        if (!idmap)
                return;
        rpc_unlink(idmap->idmap_dentry);
        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);
 }
 
@@ -449,9 +454,14 @@ 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;
 }