[PATCH 0/1] NFSv4: Reduced the footprint of the NFSv4 ID mapper

[Steve Dickson]

Reduced the footprint of the NFSv4 ID mapper

The following two (destine to be) upstream patches
reduce the footprint of the the ID mapping code 
which resolves:
    https://bugzilla.redhat.com/show_bug.cgi?id=593035

Author: Trond Myklebust 
Date:   Wed Feb 8 13:39:15 2012 -0500

NFSv4: Further reduce the footprint of the idmapper

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

Signed-off-by: Trond Myklebust 
    Reviewed-by: Jeff Layton

Author: Trond Myklebust 
Date:   Tue Feb 7 14:59:05 2012 -0500

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 
    Reviewed-by: Jeff Layton

Steve Dickson (1):
  Reduced the footprint of the NFSv4 ID mapper

...FSv4-Reduce-the-footprint-of-the-idmapper.patch |   46 ++++++++
 ...ther-reduce-the-footprint-of-the-idmapper.patch |  109 ++++++++++++++++++++
 kernel.spec                                        |    7 ++
 3 files changed, 162 insertions(+), 0 deletions(-)
 create mode 100644 0001-NFSv4-Reduce-the-footprint-of-the-idmapper.patch
 create mode 100644 0002-NFSv4-Further-reduce-the-footprint-of-the-idmapper.patch

[PATCH 1/1] Reduced the footprint of the NFSv4 ID mapper

[Steve Dickson]

Signed-off-by: Steve Dickson 
---
 ...FSv4-Reduce-the-footprint-of-the-idmapper.patch |   46 ++++++++
 ...ther-reduce-the-footprint-of-the-idmapper.patch |  109 ++++++++++++++++++++
 kernel.spec                                        |    7 ++
 3 files changed, 162 insertions(+), 0 deletions(-)
 create mode 100644 0001-NFSv4-Reduce-the-footprint-of-the-idmapper.patch
 create mode 100644 0002-NFSv4-Further-reduce-the-footprint-of-the-idmapper.patch

diff --git a/0001-NFSv4-Reduce-the-footprint-of-the-idmapper.patch b/0001-NFSv4-Reduce-the-footprint-of-the-idmapper.patch
new file mode 100644
index 0000000..4110ef9
--- /dev/null
+++ b/0001-NFSv4-Reduce-the-footprint-of-the-idmapper.patch
@@ -0,0 +1,46 @@
+diff -up linux-3.2.noarch/fs/nfs/idmap.c.orig linux-3.2.noarch/fs/nfs/idmap.c
+--- linux-3.2.noarch/fs/nfs/idmap.c.orig	2012-02-07 07:12:52.585471833 -0500
++++ linux-3.2.noarch/fs/nfs/idmap.c	2012-03-14 13:08:37.462928792 -0400
+@@ -360,7 +360,7 @@ 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 {
+@@ -424,11 +424,16 @@ 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);
+ }
+ 
+@@ -491,9 +496,14 @@ 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;
+ }
diff --git a/0002-NFSv4-Further-reduce-the-footprint-of-the-idmapper.patch b/0002-NFSv4-Further-reduce-the-footprint-of-the-idmapper.patch
new file mode 100644
index 0000000..42d1052
--- /dev/null
+++ b/0002-NFSv4-Further-reduce-the-footprint-of-the-idmapper.patch
@@ -0,0 +1,109 @@
+diff -up linux-3.2.noarch/fs/nfs/idmap.c.orig linux-3.2.noarch/fs/nfs/idmap.c
+--- linux-3.2.noarch/fs/nfs/idmap.c.orig	2012-03-14 13:08:37.462928792 -0400
++++ linux-3.2.noarch/fs/nfs/idmap.c	2012-03-14 13:10:17.076030982 -0400
+@@ -365,7 +365,7 @@ struct idmap_hashent {
+ 
+ struct idmap_hashtable {
+ 	__u8			h_type;
+-	struct idmap_hashent	h_entries[IDMAP_HASH_SZ];
++	struct idmap_hashent	*h_entries;
+ };
+ 
+ struct idmap {
+@@ -420,20 +420,39 @@ nfs_idmap_new(struct nfs_client *clp)
+ 	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);
+ }
+ 
+@@ -443,6 +462,8 @@ nfs_idmap_delete(struct nfs_client *clp)
+ 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];
+ }
+ 
+@@ -451,6 +472,8 @@ idmap_lookup_name(struct idmap_hashtable
+ {
+ 	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))
+@@ -461,6 +484,8 @@ idmap_lookup_name(struct idmap_hashtable
+ 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];
+ }
+ 
+@@ -468,6 +493,9 @@ static struct idmap_hashent *
+ 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))
+@@ -483,12 +511,14 @@ idmap_lookup_id(struct idmap_hashtable *
+ 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);
+ }
+ 
diff --git a/kernel.spec b/kernel.spec
index 83a2683..5023288 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -739,6 +739,8 @@ Patch2902: linux-2.6-v4l-dvb-uvcvideo-update.patch
 Patch3500: jbd-jbd2-validate-sb-s_first-in-journal_get_superblo.patch

# NFSv4
+Patch4000: 0001-NFSv4-Reduce-the-footprint-of-the-idmapper.patch
+Patch4001: 0002-NFSv4-Further-reduce-the-footprint-of-the-idmapper.patch

# patches headed upstream

@@ -1402,6 +1404,8 @@ ApplyPatch jbd-jbd2-validate-sb-s_first-in-journal_get_superblo.patch
 # eCryptfs

# NFSv4
+ApplyPatch 0001-NFSv4-Reduce-the-footprint-of-the-idmapper.patch
+ApplyPatch 0002-NFSv4-Further-reduce-the-footprint-of-the-idmapper.patch

# USB

@@ -2382,6 +2386,9 @@ fi
 # and build.

%changelog
+* Wed Mar 14 2012 Steve Dickson 
+- Reduce the foot print of the NFSv4 idmapping coda (bz 593035)
+
 * Mon Mar 12 2012 Josh Boyer  - 3.2.10-1
 - Linux 3.2.10

[Dave Jones]

On Wed, Mar 14, 2012 at 01:36:21PM -0400, Steve Dickson wrote:
> Reduced the footprint of the NFSv4 ID mapper
>
> The following two (destine to be) upstream patches
> reduce the footprint of the the ID mapping code 
> which resolves:
>     https://bugzilla.redhat.com/show_bug.cgi?id=593035

Added to f15/f16/f17. I'm leaving master unpatched as that'll be
moving on past 3.3 soon, so will likely inherit this fairly quickly.

Dave