pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing

This patches moves parsing of the GETDEVICEINFO XDR to kernel space, as well
as the management of complex devices.  The reason for that is we might have
multiple outstanding complex devices after a NOTIFY_DEVICEID4_CHANGE, which
device mapper or md can't handle as they claim devices exclusively.

But as is turns out simple striping / concatenation is fairly trivial to
implement anyway, so we make our life simpler by reducing the reliance
on blkmapd.  For now we still use blkmapd by feeding it synthetic SIMPLE
device XDR to translate device signatures to device numbers, but in the
long runs I have plans to eliminate it entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 32 insertions, 109 deletions

diff --git a/fs/nfs/blocklayout/rpc_pipefs.c b/fs/nfs/blocklayout/rpc_pipefs.c
index bfb0486..8d04bda 100644
--- a/fs/nfs/blocklayout/rpc_pipefs.c
+++ b/fs/nfs/blocklayout/rpc_pipefs.c
@@ -34,94 +34,53 @@
 
 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
 
-static void bl_dm_remove(struct net *net, dev_t dev)
+static void
+nfs4_encode_simple(__be32 *p, struct pnfs_block_volume *b)
 {
-	struct bl_pipe_msg bl_pipe_msg;
-	struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
-	struct bl_dev_msg bl_umount_request;
-	struct bl_msg_hdr bl_msg = {
-		.type = BL_DEVICE_UMOUNT,
-		.totallen = sizeof(bl_umount_request),
-	};
-	uint8_t *dataptr;
-	DECLARE_WAITQUEUE(wq, current);
-	struct nfs_net *nn = net_generic(net, nfs_net_id);
-
-	dprintk("Entering %s\n", __func__);
-
-	bl_pipe_msg.bl_wq = &nn->bl_wq;
-	memset(msg, 0, sizeof(*msg));
-	msg->len = sizeof(bl_msg) + bl_msg.totallen;
-	msg->data = kzalloc(msg->len, GFP_NOFS);
-	if (!msg->data)
-		goto out;
-
-	memset(&bl_umount_request, 0, sizeof(bl_umount_request));
-	bl_umount_request.major = MAJOR(dev);
-	bl_umount_request.minor = MINOR(dev);
-
-	memcpy(msg->data, &bl_msg, sizeof(bl_msg));
-	dataptr = (uint8_t *) msg->data;
-	memcpy(&dataptr[sizeof(bl_msg)], &bl_umount_request, sizeof(bl_umount_request));
-
-	add_wait_queue(&nn->bl_wq, &wq);
-	if (rpc_queue_upcall(nn->bl_device_pipe, msg) < 0) {
-		remove_wait_queue(&nn->bl_wq, &wq);
-		goto out;
+	int i;
+
+	*p++ = cpu_to_be32(1);
+	*p++ = cpu_to_be32(b->type);
+	*p++ = cpu_to_be32(b->simple.nr_sigs);
+	for (i = 0; i < b->simple.nr_sigs; i++) {
+		p = xdr_encode_hyper(p, b->simple.sigs[i].offset);
+		p = xdr_encode_opaque(p, b->simple.sigs[i].sig,
+					 b->simple.sigs[i].sig_len);
 	}
-
-	set_current_state(TASK_UNINTERRUPTIBLE);
-	schedule();
-	__set_current_state(TASK_RUNNING);
-	remove_wait_queue(&nn->bl_wq, &wq);
-
-out:
-	kfree(msg->data);
 }
 
-/*
- * Decodes pnfs_block_deviceaddr4 which is XDR encoded in dev->dev_addr_buf.
- */
-struct nfs4_deviceid_node *
-bl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *dev,
+dev_t
+bl_resolve_deviceid(struct nfs_server *server, struct pnfs_block_volume *b,
 		gfp_t gfp_mask)
 {
-	struct pnfs_block_dev *rv;
-	struct block_device *bd;
-	struct bl_pipe_msg bl_pipe_msg;
-	struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
-	struct bl_msg_hdr bl_msg = {
-		.type = BL_DEVICE_MOUNT,
-		.totallen = dev->mincount,
-	};
-	uint8_t *dataptr;
-	DECLARE_WAITQUEUE(wq, current);
-	int offset, len, i, rc;
 	struct net *net = server->nfs_client->cl_net;
 	struct nfs_net *nn = net_generic(net, nfs_net_id);
 	struct bl_dev_msg *reply = &nn->bl_mount_reply;
+	struct bl_pipe_msg bl_pipe_msg;
+	struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
+	struct bl_msg_hdr *bl_msg;
+	DECLARE_WAITQUEUE(wq, current);
+	dev_t dev = 0;
+	int rc;
 
 	dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
-	dprintk("%s: deviceid: %s, mincount: %d\n", __func__, dev->dev_id.data,
-		dev->mincount);
 
 	bl_pipe_msg.bl_wq = &nn->bl_wq;
+
+	b->simple.len += 4;	/* single volume */
+	if (b->simple.len > PAGE_SIZE)
+		return -EIO;
+
 	memset(msg, 0, sizeof(*msg));
-	msg->data = kzalloc(sizeof(bl_msg) + dev->mincount, gfp_mask);
+	msg->len = sizeof(*bl_msg) + b->simple.len;
+	msg->data = kzalloc(msg->len, gfp_mask);
 	if (!msg->data)
 		goto out;
 
-	memcpy(msg->data, &bl_msg, sizeof(bl_msg));
-	dataptr = (uint8_t *) msg->data;
-	len = dev->mincount;
-	offset = sizeof(bl_msg);
-	for (i = 0; len > 0; i++) {
-		memcpy(&dataptr[offset], page_address(dev->pages[i]),
-				len < PAGE_CACHE_SIZE ? len : PAGE_CACHE_SIZE);
-		len -= PAGE_CACHE_SIZE;
-		offset += PAGE_CACHE_SIZE;
-	}
-	msg->len = sizeof(bl_msg) + dev->mincount;
+	bl_msg = msg->data;
+	bl_msg->type = BL_DEVICE_MOUNT,
+	bl_msg->totallen = b->simple.len;
+	nfs4_encode_simple(msg->data + sizeof(*bl_msg), b);
 
 	dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
 	add_wait_queue(&nn->bl_wq, &wq);
@@ -142,46 +101,10 @@ bl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *dev,
 		goto out;
 	}
 
-	bd = blkdev_get_by_dev(MKDEV(reply->major, reply->minor),
-			       FMODE_READ, NULL);
-	if (IS_ERR(bd)) {
-		printk(KERN_WARNING "%s failed to open device %d:%d (%ld)\n",
-			__func__, reply->major, reply->minor,
-			PTR_ERR(bd));
-		goto out;
-	}
-
-	rv = kzalloc(sizeof(*rv), gfp_mask);
-	if (!rv)
-		goto out;
-
-	nfs4_init_deviceid_node(&rv->d_node, server, &dev->dev_id);
-	rv->d_bdev = bd;
-
-	dprintk("%s Created device %s with bd_block_size %u\n",
-		__func__,
-		bd->bd_disk->disk_name,
-		bd->bd_block_size);
-
-	kfree(msg->data);
-	return &rv->d_node;
-
+	dev = MKDEV(reply->major, reply->minor);
 out:
 	kfree(msg->data);
-	return NULL;
-}
-
-void
-bl_free_deviceid_node(struct nfs4_deviceid_node *d)
-{
-	struct pnfs_block_dev *dev =
-		container_of(d, struct pnfs_block_dev, d_node);
-	struct net *net = d->nfs_client->cl_net;
-
-	blkdev_put(dev->d_bdev, FMODE_READ);
-	bl_dm_remove(net, dev->d_bdev->bd_dev);
-
-	kfree(dev);
+	return dev;
 }
 
 static ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,