[PATCH v2 2/5] NFS: blocklayout pipe creation per network namespace context introduced

[Stanislav Kinsbursky <skinsbursky@parallels.com>]

This patch implements blocklayout pipe creation and registration per each
existent network namespace.
This was achived by registering NFS per-net operations, responsible for
blocklayout pipe allocation/register and unregister/destruction instead of
initialization and destruction of static "bl_device_pipe" pipe (this one was
removed).
Note, than pointer to network blocklayout pipe is stored in per-net "nfs_net"
structure, because allocating of one more per-net structure for blocklayout
module looks redundant.
This patch also changes dev_remove() function prototype (and all it's callers,
where it' requied) by adding network namespace pointer parameter, which is used
to discover proper blocklayout pipe for rpc_queue_upcall() call.

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

---
 fs/nfs/blocklayout/blocklayout.c    |   54 +++++++++++++++++++++++------------
 fs/nfs/blocklayout/blocklayout.h    |    3 +-
 fs/nfs/blocklayout/blocklayoutdev.c |    5 +++
 fs/nfs/blocklayout/blocklayoutdm.c  |    7 +++--
 fs/nfs/inode.c                      |    1 +
 fs/nfs/netns.h                      |    1 +
 6 files changed, 47 insertions(+), 24 deletions(-)

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 489f95c..ce76d05 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -46,7 +46,6 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Andy Adamson <andros@citi.umich.edu>");
 MODULE_DESCRIPTION("The NFSv4.1 pNFS Block layout driver");
 
-struct rpc_pipe *bl_device_pipe;
 wait_queue_head_t bl_wq;
 
 static void print_page(struct page *page)
@@ -1011,6 +1010,37 @@ static void nfs4blocklayout_unregister_net(struct net *net,
 	}
 }
 
+static int nfs4blocklayout_net_init(struct net *net)
+{
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+	struct dentry *dentry;
+
+	nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
+	if (IS_ERR(nn->bl_device_pipe))
+		return PTR_ERR(nn->bl_device_pipe);
+	dentry = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
+	if (IS_ERR(dentry)) {
+		rpc_destroy_pipe_data(nn->bl_device_pipe);
+		return PTR_ERR(dentry);
+	}
+	nn->bl_device_pipe->dentry = dentry;
+	return 0;
+}
+
+static void nfs4blocklayout_net_exit(struct net *net)
+{
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+	nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
+	rpc_destroy_pipe_data(nn->bl_device_pipe);
+	nn->bl_device_pipe = NULL;
+}
+
+static struct pernet_operations nfs4blocklayout_net_ops = {
+	.init = nfs4blocklayout_net_init,
+	.exit = nfs4blocklayout_net_exit,
+};
+
 static int __init nfs4blocklayout_init(void)
 {
 	struct vfsmount *mnt;
@@ -1029,24 +1059,12 @@ static int __init nfs4blocklayout_init(void)
 		ret = PTR_ERR(mnt);
 		goto out_remove;
 	}
-	bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
-	if (IS_ERR(bl_device_pipe)) {
-		ret = PTR_ERR(bl_device_pipe);
-		goto out_putrpc;
-	}
-	bl_device_pipe->dentry = nfs4blocklayout_register_net(&init_net,
-							      bl_device_pipe);
-	if (IS_ERR(bl_device_pipe->dentry)) {
-		ret = PTR_ERR(bl_device_pipe->dentry);
-		goto out_destroy_pipe;
-	}
+	ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
+	if (ret)
+		goto out_remove;
 out:
 	return ret;
 
-out_destroy_pipe:
-	rpc_destroy_pipe_data(bl_device_pipe);
-out_putrpc:
-	rpc_put_mount();
 out_remove:
 	pnfs_unregister_layoutdriver(&blocklayout_type);
 	return ret;
@@ -1057,10 +1075,8 @@ static void __exit nfs4blocklayout_exit(void)
 	dprintk("%s: NFSv4 Block Layout Driver Unregistering...\n",
 	       __func__);
 
+	unregister_pernet_subsys(&nfs4blocklayout_net_ops);
 	pnfs_unregister_layoutdriver(&blocklayout_type);
-	nfs4blocklayout_unregister_net(&init_net, bl_device_pipe);
-	rpc_destroy_pipe_data(bl_device_pipe);
-	rpc_put_mount();
 }
 
 MODULE_ALIAS("nfs-layouttype4-3");
diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h
index 046b513..10e0a62 100644
--- a/fs/nfs/blocklayout/blocklayout.h
+++ b/fs/nfs/blocklayout/blocklayout.h
@@ -37,6 +37,7 @@
 #include <linux/sunrpc/rpc_pipe_fs.h>
 
 #include "../pnfs.h"
+#include "../netns.h"
 
 #define PAGE_CACHE_SECTORS (PAGE_CACHE_SIZE >> SECTOR_SHIFT)
 #define PAGE_CACHE_SECTOR_SHIFT (PAGE_CACHE_SHIFT - SECTOR_SHIFT)
@@ -50,6 +51,7 @@ struct pnfs_block_dev {
 	struct list_head		bm_node;
 	struct nfs4_deviceid		bm_mdevid;    /* associated devid */
 	struct block_device		*bm_mdev;     /* meta device itself */
+	struct net			*net;
 };
 
 enum exstate4 {
@@ -159,7 +161,6 @@ struct bl_msg_hdr {
 	u16 totallen; /* length of entire message, including hdr itself */
 };
 
-extern struct rpc_pipe *bl_device_pipe;
 extern wait_queue_head_t bl_wq;
 
 #define BL_DEVICE_UMOUNT               0x0 /* Umount--delete devices */
diff --git a/fs/nfs/blocklayout/blocklayoutdev.c b/fs/nfs/blocklayout/blocklayoutdev.c
index 949b624..94ed978 100644
--- a/fs/nfs/blocklayout/blocklayoutdev.c
+++ b/fs/nfs/blocklayout/blocklayoutdev.c
@@ -120,6 +120,8 @@ nfs4_blk_decode_device(struct nfs_server *server,
 	DECLARE_WAITQUEUE(wq, current);
 	struct bl_dev_msg *reply = &bl_mount_reply;
 	int offset, len, i, rc;
+	struct net *net = server->nfs_client->net;
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
 
 	dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
 	dprintk("%s: deviceid: %s, mincount: %d\n", __func__, dev->dev_id.data,
@@ -146,7 +148,7 @@ nfs4_blk_decode_device(struct nfs_server *server,
 
 	dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
 	add_wait_queue(&bl_wq, &wq);
-	rc = rpc_queue_upcall(bl_device_pipe, &msg);
+	rc = rpc_queue_upcall(nn->bl_device_pipe, &msg);
 	if (rc < 0) {
 		remove_wait_queue(&bl_wq, &wq);
 		rv = ERR_PTR(rc);
@@ -181,6 +183,7 @@ nfs4_blk_decode_device(struct nfs_server *server,
 
 	rv->bm_mdev = bd;
 	memcpy(&rv->bm_mdevid, &dev->dev_id, sizeof(struct nfs4_deviceid));
+	rv->net = net;
 	dprintk("%s Created device %s with bd_block_size %u\n",
 		__func__,
 		bd->bd_disk->disk_name,
diff --git a/fs/nfs/blocklayout/blocklayoutdm.c b/fs/nfs/blocklayout/blocklayoutdm.c
index 631f254..970490f 100644
--- a/fs/nfs/blocklayout/blocklayoutdm.c
+++ b/fs/nfs/blocklayout/blocklayoutdm.c
@@ -38,7 +38,7 @@
 
 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
 
-static void dev_remove(dev_t dev)
+static void dev_remove(struct net *net, dev_t dev)
 {
 	struct rpc_pipe_msg msg;
 	struct bl_dev_msg bl_umount_request;
@@ -48,6 +48,7 @@ static void dev_remove(dev_t dev)
 	};
 	uint8_t *dataptr;
 	DECLARE_WAITQUEUE(wq, current);
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
 
 	dprintk("Entering %s\n", __func__);
 
@@ -66,7 +67,7 @@ static void dev_remove(dev_t dev)
 	msg.len = sizeof(bl_msg) + bl_msg.totallen;
 
 	add_wait_queue(&bl_wq, &wq);
-	if (rpc_queue_upcall(bl_device_pipe, &msg) < 0) {
+	if (rpc_queue_upcall(nn->bl_device_pipe, &msg) < 0) {
 		remove_wait_queue(&bl_wq, &wq);
 		goto out;
 	}
@@ -93,7 +94,7 @@ static void nfs4_blk_metadev_release(struct pnfs_block_dev *bdev)
 		printk(KERN_ERR "%s nfs4_blkdev_put returns %d\n",
 				__func__, rv);
 
-	dev_remove(bdev->bm_mdev->bd_dev);
+	dev_remove(bdev->net, bdev->bm_mdev->bd_dev);
 }
 
 void bl_free_block_dev(struct pnfs_block_dev *bdev)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 9590da3..60cf71a 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1552,6 +1552,7 @@ static void nfsiod_stop(void)
 }
 
 int nfs_net_id;
+EXPORT_SYMBOL_GPL(nfs_net_id);
 
 static int nfs_net_init(struct net *net)
 {
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
index 8c1f130..39ae4ca 100644
--- a/fs/nfs/netns.h
+++ b/fs/nfs/netns.h
@@ -6,6 +6,7 @@
 
 struct nfs_net {
 	struct cache_detail *nfs_dns_resolve;
+	struct rpc_pipe *bl_device_pipe;
 };
 
 extern int nfs_net_id;