[PATCH 0/6] NFS: create DNS resolver cache per network namespace

[PATCH 0/6] NFS: create DNS resolver cache per network namespace

[Stanislav Kinsbursky]

This patch set was created in context of clone of git
branch: git://git.linux-nfs.org/projects/trondmy/nfs-2.6.git.
tag: v3.1

This patch set depends on previous patch sets titled:
1) "SUNRPC: initial part of making pipefs work in net ns"
2) "SUNPRC: cleanup PipeFS for network-namespace-aware users"

Actually, this patch set consists of two tightly connected parts:
1) DNS resolver cache per network namespcae implementation itself
2) DNS resolver cache dentries creation by PipeFS network namespace aware
routines.

Thus this patch set is the second part of "PipeFS per network namespace"
story.

The following series consists of:

---

Stanislav Kinsbursky (6):
      SUNRPC: split cache creation and PipeFS registration
      NFS: split cache creation and PipeFS registration
      NFS: handle NFS caches dentries by network namespace aware routines
      NFS: DNS resolver cache per network namespace context introduced
      NFS: DNS resolver PipeFS notifier introduced
      NFS: remove RPC PipeFS mount point references from NFS cache routines


 fs/nfs/cache_lib.c           |   61 ++++++++++++++------
 fs/nfs/cache_lib.h           |   10 +++
 fs/nfs/dns_resolve.c         |  125 ++++++++++++++++++++++++++++++++++--------
 fs/nfs/dns_resolve.h         |   14 ++++-
 fs/nfs/inode.c               |   33 ++++++++++-
 fs/nfs/netns.h               |   13 ++++
 fs/nfs/nfs4namespace.c       |    8 ++-
 include/linux/sunrpc/cache.h |    2 +
 net/sunrpc/cache.c           |   12 ++--
 9 files changed, 218 insertions(+), 60 deletions(-)
 create mode 100644 fs/nfs/netns.h

-- 
Signature

[PATCH 1/6] SUNRPC: split cache creation and PipeFS registration

[Stanislav Kinsbursky]

This precursor patch splits SUNRPC cache creation and PipeFS registartion.
It's required for latter split of NFS DNS resolver cache creation per network
namespace context and PipeFS registration/unregistration on MOUNT/UMOUNT
events.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 fs/nfs/cache_lib.c           |    3 +++
 include/linux/sunrpc/cache.h |    2 ++
 net/sunrpc/cache.c           |   12 +++++-------
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
index c98b439..d62a895 100644
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -120,6 +120,7 @@ int nfs_cache_register(struct cache_detail *cd)
 	mnt = rpc_get_mount();
 	if (IS_ERR(mnt))
 		return PTR_ERR(mnt);
+	sunrpc_init_cache_detail(cd);
 	ret = vfs_path_lookup(mnt->mnt_root, mnt, "/cache", 0, &path);
 	if (ret)
 		goto err;
@@ -128,6 +129,7 @@ int nfs_cache_register(struct cache_detail *cd)
 	if (!ret)
 		return ret;
 err:
+	sunrpc_destroy_cache_detail(cd);
 	rpc_put_mount();
 	return ret;
 }
@@ -135,6 +137,7 @@ err:
 void nfs_cache_unregister(struct cache_detail *cd)
 {
 	sunrpc_cache_unregister_pipefs(cd);
+	sunrpc_destroy_cache_detail(cd);
 	rpc_put_mount();
 }
 
diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 5efd8ce..57d9fa7 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -202,6 +202,8 @@ extern int cache_register_net(struct cache_detail *cd, struct net *net);
 extern void cache_unregister(struct cache_detail *cd);
 extern void cache_unregister_net(struct cache_detail *cd, struct net *net);
 
+extern void sunrpc_init_cache_detail(struct cache_detail *cd);
+extern void sunrpc_destroy_cache_detail(struct cache_detail *cd);
 extern int sunrpc_cache_register_pipefs(struct dentry *parent, const char *,
 					mode_t, struct cache_detail *);
 extern void sunrpc_cache_unregister_pipefs(struct cache_detail *);
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 72ad836..320e549 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -344,7 +344,7 @@ static int current_index;
 static void do_cache_clean(struct work_struct *work);
 static struct delayed_work cache_cleaner;
 
-static void sunrpc_init_cache_detail(struct cache_detail *cd)
+void sunrpc_init_cache_detail(struct cache_detail *cd)
 {
 	rwlock_init(&cd->hash_lock);
 	INIT_LIST_HEAD(&cd->queue);
@@ -360,8 +360,9 @@ static void sunrpc_init_cache_detail(struct cache_detail *cd)
 	/* start the cleaning process */
 	schedule_delayed_work(&cache_cleaner, 0);
 }
+EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
 
-static void sunrpc_destroy_cache_detail(struct cache_detail *cd)
+void sunrpc_destroy_cache_detail(struct cache_detail *cd)
 {
 	cache_purge(cd);
 	spin_lock(&cache_list_lock);
@@ -384,6 +385,7 @@ static void sunrpc_destroy_cache_detail(struct cache_detail *cd)
 out:
 	printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
 }
+EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
 
 /* clean cache tries to find something to clean
  * and cleans it.
@@ -1785,17 +1787,14 @@ int sunrpc_cache_register_pipefs(struct dentry *parent,
 	struct dentry *dir;
 	int ret = 0;
 
-	sunrpc_init_cache_detail(cd);
 	q.name = name;
 	q.len = strlen(name);
 	q.hash = full_name_hash(q.name, q.len);
 	dir = rpc_create_cache_dir(parent, &q, umode, cd);
 	if (!IS_ERR(dir))
 		cd->u.pipefs.dir = dir;
-	else {
-		sunrpc_destroy_cache_detail(cd);
+	else
 		ret = PTR_ERR(dir);
-	}
 	return ret;
 }
 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
@@ -1804,7 +1803,6 @@ void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
 {
 	rpc_remove_cache_dir(cd->u.pipefs.dir);
 	cd->u.pipefs.dir = NULL;
-	sunrpc_destroy_cache_detail(cd);
 }
 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
 

[PATCH 2/6] NFS: split cache creation and PipeFS registration

[Stanislav Kinsbursky]

This precursor patch splits NFS cache creation and PipeFS registartion.
It's required for latter split of NFS DNS resolver cache creation per network
namespace context and PipeFS registration/unregistration on MOUNT/UMOUNT
events.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 fs/nfs/cache_lib.c   |   11 +++++++++--
 fs/nfs/cache_lib.h   |    2 ++
 fs/nfs/dns_resolve.c |   11 ++++++++++-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
index d62a895..9d79a2e 100644
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -120,7 +120,6 @@ int nfs_cache_register(struct cache_detail *cd)
 	mnt = rpc_get_mount();
 	if (IS_ERR(mnt))
 		return PTR_ERR(mnt);
-	sunrpc_init_cache_detail(cd);
 	ret = vfs_path_lookup(mnt->mnt_root, mnt, "/cache", 0, &path);
 	if (ret)
 		goto err;
@@ -129,7 +128,6 @@ int nfs_cache_register(struct cache_detail *cd)
 	if (!ret)
 		return ret;
 err:
-	sunrpc_destroy_cache_detail(cd);
 	rpc_put_mount();
 	return ret;
 }
@@ -141,3 +139,12 @@ void nfs_cache_unregister(struct cache_detail *cd)
 	rpc_put_mount();
 }
 
+void nfs_cache_init(struct cache_detail *cd)
+{
+	sunrpc_init_cache_detail(cd);
+}
+
+void nfs_cache_destroy(struct cache_detail *cd)
+{
+	sunrpc_destroy_cache_detail(cd);
+}
diff --git a/fs/nfs/cache_lib.h b/fs/nfs/cache_lib.h
index 7cf6caf..815dd66 100644
--- a/fs/nfs/cache_lib.h
+++ b/fs/nfs/cache_lib.h
@@ -23,5 +23,7 @@ extern struct nfs_cache_defer_req *nfs_cache_defer_req_alloc(void);
 extern void nfs_cache_defer_req_put(struct nfs_cache_defer_req *dreq);
 extern int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq);
 
+extern void nfs_cache_init(struct cache_detail *cd);
+extern void nfs_cache_destroy(struct cache_detail *cd);
 extern int nfs_cache_register(struct cache_detail *cd);
 extern void nfs_cache_unregister(struct cache_detail *cd);
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index a6e711a..619dea6 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -361,12 +361,21 @@ ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
 
 int nfs_dns_resolver_init(void)
 {
-	return nfs_cache_register(&nfs_dns_resolve);
+	int err;
+
+	nfs_cache_init(&nfs_dns_resolve);
+	err = nfs_cache_register(&nfs_dns_resolve);
+	if (err) {
+		nfs_cache_destroy(&nfs_dns_resolve);
+		return err;
+	}
+	return 0;
 }
 
 void nfs_dns_resolver_destroy(void)
 {
 	nfs_cache_unregister(&nfs_dns_resolve);
+	nfs_cache_destroy(&nfs_dns_resolve);
 }
 
 #endif

[PATCH 3/6] NFS: handle NFS caches dentries by network namespace aware routines

[Stanislav Kinsbursky]

This patch makes NFS caches PipeFS dentries allocated and destroyed in network
namespace context by PipeFS network namespace aware routines.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 fs/nfs/cache_lib.c   |   44 +++++++++++++++++++++++++++++++++++---------
 fs/nfs/cache_lib.h   |    4 ++--
 fs/nfs/dns_resolve.c |    4 ++--
 3 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
index 9d79a2e..5dd017b 100644
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/sunrpc/cache.h>
 #include <linux/sunrpc/rpc_pipe_fs.h>
+#include <net/net_namespace.h>
 
 #include "cache_lib.h"
 
@@ -111,20 +112,34 @@ int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq)
 	return 0;
 }
 
-int nfs_cache_register(struct cache_detail *cd)
+static int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
+{
+	int ret;
+	struct dentry *dir;
+
+	dir = rpc_d_lookup_sb(sb, "cache");
+	BUG_ON(dir == NULL);
+	ret = sunrpc_cache_register_pipefs(dir, cd->name, 0600, cd);
+	dput(dir);
+	return ret;
+}
+
+int nfs_cache_register_net(struct net *net, struct cache_detail *cd)
 {
 	struct vfsmount *mnt;
-	struct path path;
+	struct super_block *pipefs_sb;
 	int ret;
 
 	mnt = rpc_get_mount();
 	if (IS_ERR(mnt))
 		return PTR_ERR(mnt);
-	ret = vfs_path_lookup(mnt->mnt_root, mnt, "/cache", 0, &path);
-	if (ret)
+	pipefs_sb = rpc_get_sb_net(net);
+	if (!pipefs_sb) {
+		ret = -ENOENT;
 		goto err;
-	ret = sunrpc_cache_register_pipefs(path.dentry, cd->name, 0600, cd);
-	path_put(&path);
+	}
+	ret = nfs_cache_register_sb(pipefs_sb, cd);
+	rpc_put_sb_net(net);
 	if (!ret)
 		return ret;
 err:
@@ -132,10 +147,21 @@ err:
 	return ret;
 }
 
-void nfs_cache_unregister(struct cache_detail *cd)
+static void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd)
 {
-	sunrpc_cache_unregister_pipefs(cd);
-	sunrpc_destroy_cache_detail(cd);
+	if (cd->u.pipefs.dir)
+		sunrpc_cache_unregister_pipefs(cd);
+}
+
+void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd)
+{
+	struct super_block *pipefs_sb;
+
+	pipefs_sb = rpc_get_sb_net(net);
+	if (pipefs_sb) {
+		nfs_cache_unregister_sb(pipefs_sb, cd);
+		rpc_put_sb_net(net);
+	}
 	rpc_put_mount();
 }
 
diff --git a/fs/nfs/cache_lib.h b/fs/nfs/cache_lib.h
index 815dd66..e0a6cc4 100644
--- a/fs/nfs/cache_lib.h
+++ b/fs/nfs/cache_lib.h
@@ -25,5 +25,5 @@ extern int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq);
 
 extern void nfs_cache_init(struct cache_detail *cd);
 extern void nfs_cache_destroy(struct cache_detail *cd);
-extern int nfs_cache_register(struct cache_detail *cd);
-extern void nfs_cache_unregister(struct cache_detail *cd);
+extern int nfs_cache_register_net(struct net *net, struct cache_detail *cd);
+extern void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd);
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 619dea6..3cbf4b8 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -364,7 +364,7 @@ int nfs_dns_resolver_init(void)
 	int err;
 
 	nfs_cache_init(&nfs_dns_resolve);
-	err = nfs_cache_register(&nfs_dns_resolve);
+	err = nfs_cache_register_net(&init_net, &nfs_dns_resolve);
 	if (err) {
 		nfs_cache_destroy(&nfs_dns_resolve);
 		return err;
@@ -374,7 +374,7 @@ int nfs_dns_resolver_init(void)
 
 void nfs_dns_resolver_destroy(void)
 {
-	nfs_cache_unregister(&nfs_dns_resolve);
+	nfs_cache_unregister_net(&init_net, &nfs_dns_resolve);
 	nfs_cache_destroy(&nfs_dns_resolve);
 }
 

[PATCH 4/6] NFS: DNS resolver cache per network namespace context introduced

[Stanislav Kinsbursky]

This patch implements DNS resolver cache creation and registration for each
alive network namespace context.
This was done by registering NFS per-net operations, responsible for DNS cache
allocation/register and unregister/destructioning instead of initialization and
destruction of static "nfs_dns_resolve" cache detail (this one was removed).
Pointer to network dns resolver cache is stored in new per-net "nfs_net"
structure.
This patch also changes nfs_dns_resolve_name() function prototype (and it's
calls) by adding network pointer parameter, which is used to get proper DNS
resolver cache pointer for do_cache_lookup_wait() call.

Note: empty nfs_dns_resolver_init() and nfs_dns_resolver_destroy() functions
will be used in next patch in the series.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 fs/nfs/dns_resolve.c   |   96 ++++++++++++++++++++++++++++++++----------------
 fs/nfs/dns_resolve.h   |   14 ++++++-
 fs/nfs/inode.c         |   33 +++++++++++++++--
 fs/nfs/netns.h         |   13 +++++++
 fs/nfs/nfs4namespace.c |    8 +++-
 5 files changed, 123 insertions(+), 41 deletions(-)
 create mode 100644 fs/nfs/netns.h

diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 3cbf4b8..9aea78a 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -11,7 +11,7 @@
 #include <linux/sunrpc/clnt.h>
 #include <linux/dns_resolver.h>
 
-ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
+ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
 		struct sockaddr *sa, size_t salen)
 {
 	ssize_t ret;
@@ -43,12 +43,11 @@ ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
 
 #include "dns_resolve.h"
 #include "cache_lib.h"
+#include "netns.h"
 
 #define NFS_DNS_HASHBITS 4
 #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
 
-static struct cache_head *nfs_dns_table[NFS_DNS_HASHTBL_SIZE];
-
 struct nfs_dns_ent {
 	struct cache_head h;
 
@@ -259,21 +258,6 @@ out:
 	return ret;
 }
 
-static struct cache_detail nfs_dns_resolve = {
-	.owner = THIS_MODULE,
-	.hash_size = NFS_DNS_HASHTBL_SIZE,
-	.hash_table = nfs_dns_table,
-	.name = "dns_resolve",
-	.cache_put = nfs_dns_ent_put,
-	.cache_upcall = nfs_dns_upcall,
-	.cache_parse = nfs_dns_parse,
-	.cache_show = nfs_dns_show,
-	.match = nfs_dns_match,
-	.init = nfs_dns_ent_init,
-	.update = nfs_dns_ent_update,
-	.alloc = nfs_dns_ent_alloc,
-};
-
 static int do_cache_lookup(struct cache_detail *cd,
 		struct nfs_dns_ent *key,
 		struct nfs_dns_ent **item,
@@ -336,8 +320,8 @@ out:
 	return ret;
 }
 
-ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
-		struct sockaddr *sa, size_t salen)
+ssize_t nfs_dns_resolve_name(struct net *net, char *name,
+		size_t namelen, struct sockaddr *sa, size_t salen)
 {
 	struct nfs_dns_ent key = {
 		.hostname = name,
@@ -345,37 +329,83 @@ ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
 	};
 	struct nfs_dns_ent *item = NULL;
 	ssize_t ret;
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
 
-	ret = do_cache_lookup_wait(&nfs_dns_resolve, &key, &item);
+	ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
 	if (ret == 0) {
 		if (salen >= item->addrlen) {
 			memcpy(sa, &item->addr, item->addrlen);
 			ret = item->addrlen;
 		} else
 			ret = -EOVERFLOW;
-		cache_put(&item->h, &nfs_dns_resolve);
+		cache_put(&item->h, nn->nfs_dns_resolve);
 	} else if (ret == -ENOENT)
 		ret = -ESRCH;
 	return ret;
 }
 
-int nfs_dns_resolver_init(void)
+int nfs_dns_resolver_cache_init(struct net *net)
 {
-	int err;
+	int err = -ENOMEM;
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+	struct cache_detail *cd;
+	struct cache_head **tbl;
+
+	cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL);
+	if (cd == NULL)
+		goto err_cd;
+
+	tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *),
+			GFP_KERNEL);
+	if (tbl == NULL)
+		goto err_tbl;
+
+	cd->owner = THIS_MODULE,
+	cd->hash_size = NFS_DNS_HASHTBL_SIZE,
+	cd->hash_table = tbl,
+	cd->name = "dns_resolve",
+	cd->cache_put = nfs_dns_ent_put,
+	cd->cache_upcall = nfs_dns_upcall,
+	cd->cache_parse = nfs_dns_parse,
+	cd->cache_show = nfs_dns_show,
+	cd->match = nfs_dns_match,
+	cd->init = nfs_dns_ent_init,
+	cd->update = nfs_dns_ent_update,
+	cd->alloc = nfs_dns_ent_alloc,
+
+	nfs_cache_init(cd);
+	err = nfs_cache_register_net(net, cd);
+	if (err)
+		goto err_reg;
+	nn->nfs_dns_resolve = cd;
+	return 0;
 
-	nfs_cache_init(&nfs_dns_resolve);
-	err = nfs_cache_register_net(&init_net, &nfs_dns_resolve);
-	if (err) {
-		nfs_cache_destroy(&nfs_dns_resolve);
-		return err;
-	}
+err_reg:
+	nfs_cache_destroy(cd);
+	kfree(cd->hash_table);
+err_tbl:
+	kfree(cd);
+err_cd:
+	return err;
+}
+
+void nfs_dns_resolver_cache_destroy(struct net *net)
+{
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+	struct cache_detail *cd = nn->nfs_dns_resolve;
+
+	nfs_cache_unregister_net(net, cd);
+	nfs_cache_destroy(cd);
+	kfree(cd->hash_table);
+	kfree(cd);
+}
+
+int nfs_dns_resolver_init(void)
+{
 	return 0;
 }
 
 void nfs_dns_resolver_destroy(void)
 {
-	nfs_cache_unregister_net(&init_net, &nfs_dns_resolve);
-	nfs_cache_destroy(&nfs_dns_resolve);
 }
-
 #endif
diff --git a/fs/nfs/dns_resolve.h b/fs/nfs/dns_resolve.h
index 199bb55..2e4f596 100644
--- a/fs/nfs/dns_resolve.h
+++ b/fs/nfs/dns_resolve.h
@@ -15,12 +15,22 @@ static inline int nfs_dns_resolver_init(void)
 
 static inline void nfs_dns_resolver_destroy(void)
 {}
+
+static inline int nfs_dns_resolver_cache_init(struct net *net)
+{
+	return 0;
+}
+
+static inline void nfs_dns_resolver_cache_destroy(struct net *net)
+{}
 #else
 extern int nfs_dns_resolver_init(void);
 extern void nfs_dns_resolver_destroy(void);
+extern int nfs_dns_resolver_cache_init(struct net *net);
+extern void nfs_dns_resolver_cache_destroy(struct net *net);
 #endif
 
-extern ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
-		struct sockaddr *sa, size_t salen);
+extern ssize_t nfs_dns_resolve_name(struct net *net, char *name,
+		size_t namelen,	struct sockaddr *sa, size_t salen);
 
 #endif
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index fe12037..84d8506 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -50,6 +50,7 @@
 #include "fscache.h"
 #include "dns_resolve.h"
 #include "pnfs.h"
+#include "netns.h"
 
 #define NFSDBG_FACILITY		NFSDBG_VFS
 
@@ -1550,6 +1551,25 @@ static void nfsiod_stop(void)
 	destroy_workqueue(wq);
 }
 
+int nfs_net_id;
+
+static int nfs_net_init(struct net *net)
+{
+	return nfs_dns_resolver_cache_init(net);
+}
+
+static void nfs_net_exit(struct net *net)
+{
+	nfs_dns_resolver_cache_destroy(net);
+}
+
+static struct pernet_operations nfs_net_ops = {
+	.init = nfs_net_init,
+	.exit = nfs_net_exit,
+	.id   = &nfs_net_id,
+	.size = sizeof(struct nfs_net),
+};
+
 /*
  * Initialize NFS
  */
@@ -1559,10 +1579,14 @@ static int __init init_nfs_fs(void)
 
 	err = nfs_idmap_init();
 	if (err < 0)
-		goto out9;
+		goto out10;
 
 	err = nfs_dns_resolver_init();
 	if (err < 0)
+		goto out9;
+
+	err = register_pernet_subsys(&nfs_net_ops);
+	if (err < 0)
 		goto out8;
 
 	err = nfs_fscache_register();
@@ -1623,10 +1647,12 @@ out5:
 out6:
 	nfs_fscache_unregister();
 out7:
-	nfs_dns_resolver_destroy();
+	unregister_pernet_subsys(&nfs_net_ops);
 out8:
-	nfs_idmap_quit();
+	nfs_dns_resolver_destroy();
 out9:
+	nfs_idmap_quit();
+out10:
 	return err;
 }
 
@@ -1638,6 +1664,7 @@ static void __exit exit_nfs_fs(void)
 	nfs_destroy_inodecache();
 	nfs_destroy_nfspagecache();
 	nfs_fscache_unregister();
+	unregister_pernet_subsys(&nfs_net_ops);
 	nfs_dns_resolver_destroy();
 	nfs_idmap_quit();
 #ifdef CONFIG_PROC_FS
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
new file mode 100644
index 0000000..8c1f130
--- /dev/null
+++ b/fs/nfs/netns.h
@@ -0,0 +1,13 @@
+#ifndef __NFS_NETNS_H__
+#define __NFS_NETNS_H__
+
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+struct nfs_net {
+	struct cache_detail *nfs_dns_resolve;
+};
+
+extern int nfs_net_id;
+
+#endif
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index bb80c49..919a369 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -94,13 +94,14 @@ static int nfs4_validate_fspath(struct dentry *dentry,
 }
 
 static size_t nfs_parse_server_name(char *string, size_t len,
-		struct sockaddr *sa, size_t salen)
+		struct sockaddr *sa, size_t salen, struct nfs_server *server)
 {
 	ssize_t ret;
 
 	ret = rpc_pton(string, len, sa, salen);
 	if (ret == 0) {
-		ret = nfs_dns_resolve_name(string, len, sa, salen);
+		ret = nfs_dns_resolve_name(server->client->cl_xprt->xprt_net,
+					   string, len, sa, salen);
 		if (ret < 0)
 			ret = 0;
 	}
@@ -137,7 +138,8 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 			continue;
 
 		mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
-				mountdata->addr, addr_bufsize);
+				mountdata->addr, addr_bufsize,
+				NFS_SB(mountdata->sb));
 		if (mountdata->addrlen == 0)
 			continue;
 

[PATCH 5/6] NFS: DNS resolver PipeFS notifier introduced

[Stanislav Kinsbursky]

This patch subscribes DNS resolver caches to RPC pipefs notifications. Notifier
is registering on NFS module load. This notifier callback is responsible for
creation/destruction of PipeFS DNS resolver cache directory.
Note that no locking required in notifier callback because PipeFS superblock
pointer is passed as an argument from it's creation or destruction routine and
thus we can be sure about it's validity.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 fs/nfs/cache_lib.c   |    4 ++--
 fs/nfs/cache_lib.h   |    4 ++++
 fs/nfs/dns_resolve.c |   38 +++++++++++++++++++++++++++++++++++++-
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
index 5dd017b..5905a31 100644
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -112,7 +112,7 @@ int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq)
 	return 0;
 }
 
-static int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
+int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
 {
 	int ret;
 	struct dentry *dir;
@@ -147,7 +147,7 @@ err:
 	return ret;
 }
 
-static void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd)
+void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd)
 {
 	if (cd->u.pipefs.dir)
 		sunrpc_cache_unregister_pipefs(cd);
diff --git a/fs/nfs/cache_lib.h b/fs/nfs/cache_lib.h
index e0a6cc4..317db95 100644
--- a/fs/nfs/cache_lib.h
+++ b/fs/nfs/cache_lib.h
@@ -27,3 +27,7 @@ extern void nfs_cache_init(struct cache_detail *cd);
 extern void nfs_cache_destroy(struct cache_detail *cd);
 extern int nfs_cache_register_net(struct net *net, struct cache_detail *cd);
 extern void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd);
+extern int nfs_cache_register_sb(struct super_block *sb,
+				 struct cache_detail *cd);
+extern void nfs_cache_unregister_sb(struct super_block *sb,
+				    struct cache_detail *cd);
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 9aea78a..200eb67 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -40,6 +40,7 @@ ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/cache.h>
 #include <linux/sunrpc/svcauth.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
 
 #include "dns_resolve.h"
 #include "cache_lib.h"
@@ -400,12 +401,47 @@ void nfs_dns_resolver_cache_destroy(struct net *net)
 	kfree(cd);
 }
 
+static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
+			   void *ptr)
+{
+	struct super_block *sb = ptr;
+	struct net *net = sb->s_fs_info;
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+	struct cache_detail *cd = nn->nfs_dns_resolve;
+	int ret = 0;
+
+	if (cd == NULL)
+		return 0;
+
+	if (!try_module_get(THIS_MODULE))
+		return 0;
+
+	switch (event) {
+	case RPC_PIPEFS_MOUNT:
+		ret = nfs_cache_register_sb(sb, cd);
+		break;
+	case RPC_PIPEFS_UMOUNT:
+		nfs_cache_unregister_sb(sb, cd);
+		break;
+	default:
+		ret = -ENOTSUPP;
+		break;
+	}
+	module_put(THIS_MODULE);
+	return ret;
+}
+
+static struct notifier_block nfs_dns_resolver_block = {
+	.notifier_call	= rpc_pipefs_event,
+};
+
 int nfs_dns_resolver_init(void)
 {
-	return 0;
+	return rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
 }
 
 void nfs_dns_resolver_destroy(void)
 {
+	rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
 }
 #endif

[PATCH 6/6] NFS: remove RPC PipeFS mount point references from NFS cache routines

[Stanislav Kinsbursky]

This is a cleanup patch. We don't need this reference anymore, because DNS
resolver cache now creates it's dentries in per-net operations and on PipeFS
mount/umount notification.
Note that nfs_cache_register_net() now returns 0 instead of -ENOENT in case of
PiepFS superblock absence. This is ok, Dns resolver cache will be regestered on
PipeFS mount event.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 fs/nfs/cache_lib.c |   19 ++++---------------
 1 files changed, 4 insertions(+), 15 deletions(-)

diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
index 5905a31..dded263 100644
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -126,24 +126,14 @@ int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
 
 int nfs_cache_register_net(struct net *net, struct cache_detail *cd)
 {
-	struct vfsmount *mnt;
 	struct super_block *pipefs_sb;
-	int ret;
+	int ret = 0;
 
-	mnt = rpc_get_mount();
-	if (IS_ERR(mnt))
-		return PTR_ERR(mnt);
 	pipefs_sb = rpc_get_sb_net(net);
-	if (!pipefs_sb) {
-		ret = -ENOENT;
-		goto err;
+	if (pipefs_sb) {
+		ret = nfs_cache_register_sb(pipefs_sb, cd);
+		rpc_put_sb_net(net);
 	}
-	ret = nfs_cache_register_sb(pipefs_sb, cd);
-	rpc_put_sb_net(net);
-	if (!ret)
-		return ret;
-err:
-	rpc_put_mount();
 	return ret;
 }
 
@@ -162,7 +152,6 @@ void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd)
 		nfs_cache_unregister_sb(pipefs_sb, cd);
 		rpc_put_sb_net(net);
 	}
-	rpc_put_mount();
 }
 
 void nfs_cache_init(struct cache_detail *cd)