[ 015/108] NFSv4: Further reduce the footprint of the idmapper

Ben Hutchings
2012-07-23T02:08:37Z

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

commit 685f50f9188ac1e8244d0340a9d6ea36b6136cec upstream.

Don't allocate the legacy idmapper tables until we actually need
them.

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 | 42 ++++++++++++++++++++++++++++++++++++------
1 file changed, 36 insertions(+), 6 deletions(-)

--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -323,7 +323,7 @@

struct idmap_hashtable {
__u8 h_type;
- struct idmap_hashent h_entries[IDMAP_HASH_SZ];
+ struct idmap_hashent *h_entries;
};

struct idmap {
@@ -378,20 +378,39 @@
return 0;
}

+static void
+idmap_alloc_hashtable(struct idmap_hashtable *h)
+{
+ if (h->h_entries != NULL)
+ return;
+ h->h_entries = kcalloc(IDMAP_HASH_SZ,
+ sizeof(*h->h_entries),
+ GFP_KERNEL);
+}
+
+static void
+idmap_free_hashtable(struct idmap_hashtable *h)
+{
+ int i;
+
+ if (h->h_entries == NULL)
+ return;
+ for (i = 0; i < IDMAP_HASH_SZ; i++)
+ kfree(h->h_entries[i].ih_name);
+ kfree(h->h_entries);
+}
+
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);
+ idmap_free_hashtable(&idmap->idmap_user_hash);
+ idmap_free_hashtable(&idmap->idmap_group_hash);
kfree(idmap);
}

@@ -401,6 +420,8 @@
static inline struct idmap_hashent *
idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
{
+ if (h->h_entries == NULL)
+ return NULL;
return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
}

@@ -409,6 +430,8 @@
{
struct idmap_hashent *he = idmap_name_hash(h, name, len);

+ if (he == NULL)
+ return NULL;
if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
return NULL;
if (time_after(jiffies, he->ih_expires))
@@ -419,6 +442,8 @@
static inline struct idmap_hashent *
idmap_id_hash(struct idmap_hashtable* h, __u32 id)
{
+ if (h->h_entries == NULL)
+ return NULL;
return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
}

@@ -426,6 +451,9 @@
idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
{
struct idmap_hashent *he = idmap_id_hash(h, id);
+
+ if (he == NULL)
+ return NULL;
if (he->ih_id != id || he->ih_namelen == 0)
return NULL;
if (time_after(jiffies, he->ih_expires))
@@ -441,12 +469,14 @@
static inline struct idmap_hashent *
idmap_alloc_name(struct idmap_hashtable *h, char *name, size_t len)
{
+ idmap_alloc_hashtable(h);
return idmap_name_hash(h, name, len);
}

static inline struct idmap_hashent *
idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
{
+ idmap_alloc_hashtable(h);
return idmap_id_hash(h, id);
}