NFS: DNS resolver cache per network namespace context introduced

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>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 30 insertions, 3 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index f649fba8c384..0335f6e4ff7e 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -51,6 +51,7 @@
 #include "fscache.h"
 #include "dns_resolve.h"
 #include "pnfs.h"
+#include "netns.h"
 
 #define NFSDBG_FACILITY		NFSDBG_VFS
 
@@ -1552,6 +1553,25 @@ 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
  */
@@ -1561,10 +1581,14 @@ 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();
@@ -1625,10 +1649,12 @@ 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;
 }
 
@@ -1640,6 +1666,7 @@ 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