[ 014/108] NFSv4: Reduce the footprint of the idmapper

Ben Hutchings
2012-07-23T02:09:26Z

From: Trond Myklebust <Trond.Myklebust@netapp.com>

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>
---
fs/nfs/idmap.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -318,7 +318,7 @@
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 @@
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 @@
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;
}