fs/nfs/blocklayout/dev.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2014-2016 Christoph Hellwig.
  */
 #include <linux/sunrpc/svc.h>
 #include <linux/blkdev.h>
 #include <linux/nfs4.h>
 #include <linux/nfs_fs.h>
 #include <linux/nfs_xdr.h>
 #include <linux/pr.h>

 #include "blocklayout.h"

 #define NFSDBG_FACILITY		NFSDBG_PNFS_LD

 static void
 bl_free_device(struct pnfs_block_dev *dev)
 {
 	if (dev->nr_children) {
 		int i;

 		for (i = 0; i < dev->nr_children; i++)
 			bl_free_device(&dev->children[i]);
 		kfree(dev->children);
 	} else {
 		if (dev->pr_registered) {
 			const struct pr_ops *ops =
 				dev->bdev->bd_disk->fops->pr_ops;
 			int error;

 			error = ops->pr_register(dev->bdev, dev->pr_key, 0,
 				false);
 			if (error)
 				pr_err("failed to unregister PR key.\n");
 		}

 		if (dev->bdev)
 			blkdev_put(dev->bdev, FMODE_READ | FMODE_WRITE);
 	}
 }

 void
 bl_free_deviceid_node(struct nfs4_deviceid_node *d)
 {
 	struct pnfs_block_dev *dev =
 		container_of(d, struct pnfs_block_dev, node);

 	bl_free_device(dev);
 	kfree_rcu(dev, node.rcu);
 }

 static int
 nfs4_block_decode_volume(struct xdr_stream *xdr, struct pnfs_block_volume *b)
 {
 	__be32 *p;
 	int i;

 	p = xdr_inline_decode(xdr, 4);
 	if (!p)
 		return -EIO;
 	b->type = be32_to_cpup(p++);

 	switch (b->type) {
 	case PNFS_BLOCK_VOLUME_SIMPLE:
 		p = xdr_inline_decode(xdr, 4);
 		if (!p)
 			return -EIO;
 		b->simple.nr_sigs = be32_to_cpup(p++);
 		if (!b->simple.nr_sigs || b->simple.nr_sigs > PNFS_BLOCK_MAX_UUIDS) {
 			dprintk("Bad signature count: %d\n", b->simple.nr_sigs);
 			return -EIO;
 		}

 		b->simple.len = 4 + 4;
 		for (i = 0; i < b->simple.nr_sigs; i++) {
 			p = xdr_inline_decode(xdr, 8 + 4);
 			if (!p)
 				return -EIO;
 			p = xdr_decode_hyper(p, &b->simple.sigs[i].offset);
 			b->simple.sigs[i].sig_len = be32_to_cpup(p++);
 			if (b->simple.sigs[i].sig_len > PNFS_BLOCK_UUID_LEN) {
 				pr_info("signature too long: %d\n",
 					b->simple.sigs[i].sig_len);
 				return -EIO;
 			}

 			p = xdr_inline_decode(xdr, b->simple.sigs[i].sig_len);
 			if (!p)
 				return -EIO;
 			memcpy(&b->simple.sigs[i].sig, p,
 				b->simple.sigs[i].sig_len);

 			b->simple.len += 8 + 4 + \
 				(XDR_QUADLEN(b->simple.sigs[i].sig_len) << 2);
 		}
 		break;
 	case PNFS_BLOCK_VOLUME_SLICE:
 		p = xdr_inline_decode(xdr, 8 + 8 + 4);
 		if (!p)
 			return -EIO;
 		p = xdr_decode_hyper(p, &b->slice.start);
 		p = xdr_decode_hyper(p, &b->slice.len);
 		b->slice.volume = be32_to_cpup(p++);
 		break;
 	case PNFS_BLOCK_VOLUME_CONCAT:
 		p = xdr_inline_decode(xdr, 4);
 		if (!p)
 			return -EIO;

 		b->concat.volumes_count = be32_to_cpup(p++);
 		if (b->concat.volumes_count > PNFS_BLOCK_MAX_DEVICES) {
 			dprintk("Too many volumes: %d\n", b->concat.volumes_count);
 			return -EIO;
 		}

 		p = xdr_inline_decode(xdr, b->concat.volumes_count * 4);
 		if (!p)
 			return -EIO;
 		for (i = 0; i < b->concat.volumes_count; i++)
 			b->concat.volumes[i] = be32_to_cpup(p++);
 		break;
 	case PNFS_BLOCK_VOLUME_STRIPE:
 		p = xdr_inline_decode(xdr, 8 + 4);
 		if (!p)
 			return -EIO;

 		p = xdr_decode_hyper(p, &b->stripe.chunk_size);
 		b->stripe.volumes_count = be32_to_cpup(p++);
 		if (b->stripe.volumes_count > PNFS_BLOCK_MAX_DEVICES) {
 			dprintk("Too many volumes: %d\n", b->stripe.volumes_count);
 			return -EIO;
 		}

 		p = xdr_inline_decode(xdr, b->stripe.volumes_count * 4);
 		if (!p)
 			return -EIO;
 		for (i = 0; i < b->stripe.volumes_count; i++)
 			b->stripe.volumes[i] = be32_to_cpup(p++);
 		break;
 	case PNFS_BLOCK_VOLUME_SCSI:
 		p = xdr_inline_decode(xdr, 4 + 4 + 4);
 		if (!p)
 			return -EIO;
 		b->scsi.code_set = be32_to_cpup(p++);
 		b->scsi.designator_type = be32_to_cpup(p++);
 		b->scsi.designator_len = be32_to_cpup(p++);
 		p = xdr_inline_decode(xdr, b->scsi.designator_len);
 		if (!p)
 			return -EIO;
 		if (b->scsi.designator_len > 256)
 			return -EIO;
 		memcpy(&b->scsi.designator, p, b->scsi.designator_len);
 		p = xdr_inline_decode(xdr, 8);
 		if (!p)
 			return -EIO;
 		p = xdr_decode_hyper(p, &b->scsi.pr_key);
 		break;
 	default:
 		dprintk("unknown volume type!\n");
 		return -EIO;
 	}

 	return 0;
 }

 static bool bl_map_simple(struct pnfs_block_dev *dev, u64 offset,
 		struct pnfs_block_dev_map *map)
 {
 	map->start = dev->start;
 	map->len = dev->len;
 	map->disk_offset = dev->disk_offset;
 	map->bdev = dev->bdev;
 	return true;
 }

 static bool bl_map_concat(struct pnfs_block_dev *dev, u64 offset,
 		struct pnfs_block_dev_map *map)
 {
 	int i;

 	for (i = 0; i < dev->nr_children; i++) {
 		struct pnfs_block_dev *child = &dev->children[i];

 		if (child->start > offset ||
 		    child->start + child->len <= offset)
 			continue;

 		child->map(child, offset - child->start, map);
 		return true;
 	}

 	dprintk("%s: ran off loop!\n", __func__);
 	return false;
 }

 static bool bl_map_stripe(struct pnfs_block_dev *dev, u64 offset,
 		struct pnfs_block_dev_map *map)
 {
 	struct pnfs_block_dev *child;
 	u64 chunk;
 	u32 chunk_idx;
 	u64 disk_offset;

 	chunk = div_u64(offset, dev->chunk_size);
 	div_u64_rem(chunk, dev->nr_children, &chunk_idx);

 	if (chunk_idx >= dev->nr_children) {
 		dprintk("%s: invalid chunk idx %d (%lld/%lld)\n",
 			__func__, chunk_idx, offset, dev->chunk_size);
 		/* error, should not happen */
 		return false;
 	}

 	/* truncate offset to the beginning of the stripe */
 	offset = chunk * dev->chunk_size;

 	/* disk offset of the stripe */
 	disk_offset = div_u64(offset, dev->nr_children);

 	child = &dev->children[chunk_idx];
 	child->map(child, disk_offset, map);

 	map->start += offset;
 	map->disk_offset += disk_offset;
 	map->len = dev->chunk_size;
 	return true;
 }

 static int
 bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask);


 static int
 bl_parse_simple(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
 {
 	struct pnfs_block_volume *v = &volumes[idx];
 	struct block_device *bdev;
 	dev_t dev;

 	dev = bl_resolve_deviceid(server, v, gfp_mask);
 	if (!dev)
 		return -EIO;

 	bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_WRITE, NULL);
 	if (IS_ERR(bdev)) {
 		printk(KERN_WARNING "pNFS: failed to open device %d:%d (%ld)\n",
 			MAJOR(dev), MINOR(dev), PTR_ERR(bdev));
 		return PTR_ERR(bdev);
 	}
 	d->bdev = bdev;


 	d->len = i_size_read(d->bdev->bd_inode);
 	d->map = bl_map_simple;

 	printk(KERN_INFO "pNFS: using block device %s\n",
 		d->bdev->bd_disk->disk_name);
 	return 0;
 }

 static bool
 bl_validate_designator(struct pnfs_block_volume *v)
 {
 	switch (v->scsi.designator_type) {
 	case PS_DESIGNATOR_EUI64:
 		if (v->scsi.code_set != PS_CODE_SET_BINARY)
 			return false;

 		if (v->scsi.designator_len != 8 &&
 		    v->scsi.designator_len != 10 &&
 		    v->scsi.designator_len != 16)
 			return false;

 		return true;
 	case PS_DESIGNATOR_NAA:
 		if (v->scsi.code_set != PS_CODE_SET_BINARY)
 			return false;

 		if (v->scsi.designator_len != 8 &&
 		    v->scsi.designator_len != 16)
 			return false;

 		return true;
 	case PS_DESIGNATOR_T10:
 	case PS_DESIGNATOR_NAME:
 		pr_err("pNFS: unsupported designator "
 			"(code set %d, type %d, len %d.\n",
 			v->scsi.code_set,
 			v->scsi.designator_type,
 			v->scsi.designator_len);
 		return false;
 	default:
 		pr_err("pNFS: invalid designator "
 			"(code set %d, type %d, len %d.\n",
 			v->scsi.code_set,
 			v->scsi.designator_type,
 			v->scsi.designator_len);
 		return false;
 	}
 }

 /*
  * Try to open the udev path for the WWN.  At least on Debian the udev
  * by-id path will always point to the dm-multipath device if one exists.
  */
 static struct block_device *
 bl_open_udev_path(struct pnfs_block_volume *v)
 {
 	struct block_device *bdev;
 	const char *devname;

 	devname = kasprintf(GFP_KERNEL, "/dev/disk/by-id/wwn-0x%*phN",
 				v->scsi.designator_len, v->scsi.designator);
 	if (!devname)
 		return ERR_PTR(-ENOMEM);

 	bdev = blkdev_get_by_path(devname, FMODE_READ | FMODE_WRITE, NULL);
 	if (IS_ERR(bdev)) {
 		pr_warn("pNFS: failed to open device %s (%ld)\n",
 			devname, PTR_ERR(bdev));
 	}

 	kfree(devname);
 	return bdev;
 }

 /*
  * Try to open the RH/Fedora specific dm-mpath udev path for this WWN, as the
  * wwn- links will only point to the first discovered SCSI device there.
  */
 static struct block_device *
 bl_open_dm_mpath_udev_path(struct pnfs_block_volume *v)
 {
 	struct block_device *bdev;
 	const char *devname;

 	devname = kasprintf(GFP_KERNEL,
 			"/dev/disk/by-id/dm-uuid-mpath-%d%*phN",
 			v->scsi.designator_type,
 			v->scsi.designator_len, v->scsi.designator);
 	if (!devname)
 		return ERR_PTR(-ENOMEM);

 	bdev = blkdev_get_by_path(devname, FMODE_READ | FMODE_WRITE, NULL);
 	kfree(devname);
 	return bdev;
 }

 static int
 bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
 {
 	struct pnfs_block_volume *v = &volumes[idx];
 	struct block_device *bdev;
 	const struct pr_ops *ops;
 	int error;

 	if (!bl_validate_designator(v))
 		return -EINVAL;

 	bdev = bl_open_dm_mpath_udev_path(v);
 	if (IS_ERR(bdev))
 		bdev = bl_open_udev_path(v);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 	d->bdev = bdev;

 	d->len = i_size_read(d->bdev->bd_inode);
 	d->map = bl_map_simple;
 	d->pr_key = v->scsi.pr_key;

 	pr_info("pNFS: using block device %s (reservation key 0x%llx)\n",
 		d->bdev->bd_disk->disk_name, d->pr_key);

 	ops = d->bdev->bd_disk->fops->pr_ops;
 	if (!ops) {
 		pr_err("pNFS: block device %s does not support reservations.",
 				d->bdev->bd_disk->disk_name);
 		error = -EINVAL;
 		goto out_blkdev_put;
 	}

 	error = ops->pr_register(d->bdev, 0, d->pr_key, true);
 	if (error) {
 		pr_err("pNFS: failed to register key for block device %s.",
 				d->bdev->bd_disk->disk_name);
 		goto out_blkdev_put;
 	}

 	d->pr_registered = true;
 	return 0;

 out_blkdev_put:
 	blkdev_put(d->bdev, FMODE_READ | FMODE_WRITE);
 	return error;
 }

 static int
 bl_parse_slice(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
 {
 	struct pnfs_block_volume *v = &volumes[idx];
 	int ret;

 	ret = bl_parse_deviceid(server, d, volumes, v->slice.volume, gfp_mask);
 	if (ret)
 		return ret;

 	d->disk_offset = v->slice.start;
 	d->len = v->slice.len;
 	return 0;
 }

 static int
 bl_parse_concat(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
 {
 	struct pnfs_block_volume *v = &volumes[idx];
 	u64 len = 0;
 	int ret, i;

 	d->children = kcalloc(v->concat.volumes_count,
 			sizeof(struct pnfs_block_dev), GFP_KERNEL);
 	if (!d->children)
 		return -ENOMEM;

 	for (i = 0; i < v->concat.volumes_count; i++) {
 		ret = bl_parse_deviceid(server, &d->children[i],
 				volumes, v->concat.volumes[i], gfp_mask);
 		if (ret)
 			return ret;

 		d->nr_children++;
 		d->children[i].start += len;
 		len += d->children[i].len;
 	}

 	d->len = len;
 	d->map = bl_map_concat;
 	return 0;
 }

 static int
 bl_parse_stripe(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
 {
 	struct pnfs_block_volume *v = &volumes[idx];
 	u64 len = 0;
 	int ret, i;

 	d->children = kcalloc(v->stripe.volumes_count,
 			sizeof(struct pnfs_block_dev), GFP_KERNEL);
 	if (!d->children)
 		return -ENOMEM;

 	for (i = 0; i < v->stripe.volumes_count; i++) {
 		ret = bl_parse_deviceid(server, &d->children[i],
 				volumes, v->stripe.volumes[i], gfp_mask);
 		if (ret)
 			return ret;

 		d->nr_children++;
 		len += d->children[i].len;
 	}

 	d->len = len;
 	d->chunk_size = v->stripe.chunk_size;
 	d->map = bl_map_stripe;
 	return 0;
 }

 static int
 bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
 {
 	switch (volumes[idx].type) {
 	case PNFS_BLOCK_VOLUME_SIMPLE:
 		return bl_parse_simple(server, d, volumes, idx, gfp_mask);
 	case PNFS_BLOCK_VOLUME_SLICE:
 		return bl_parse_slice(server, d, volumes, idx, gfp_mask);
 	case PNFS_BLOCK_VOLUME_CONCAT:
 		return bl_parse_concat(server, d, volumes, idx, gfp_mask);
 	case PNFS_BLOCK_VOLUME_STRIPE:
 		return bl_parse_stripe(server, d, volumes, idx, gfp_mask);
 	case PNFS_BLOCK_VOLUME_SCSI:
 		return bl_parse_scsi(server, d, volumes, idx, gfp_mask);
 	default:
 		dprintk("unsupported volume type: %d\n", volumes[idx].type);
 		return -EIO;
 	}
 }

 struct nfs4_deviceid_node *
 bl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
 		gfp_t gfp_mask)
 {
 	struct nfs4_deviceid_node *node = NULL;
 	struct pnfs_block_volume *volumes;
 	struct pnfs_block_dev *top;
 	struct xdr_stream xdr;
 	struct xdr_buf buf;
 	struct page *scratch;
 	int nr_volumes, ret, i;
 	__be32 *p;

 	scratch = alloc_page(gfp_mask);
 	if (!scratch)
 		goto out;

 	xdr_init_decode_pages(&xdr, &buf, pdev->pages, pdev->pglen);
 	xdr_set_scratch_buffer(&xdr, page_address(scratch), PAGE_SIZE);

 	p = xdr_inline_decode(&xdr, sizeof(__be32));
 	if (!p)
 		goto out_free_scratch;
 	nr_volumes = be32_to_cpup(p++);

 	volumes = kcalloc(nr_volumes, sizeof(struct pnfs_block_volume),
 			  gfp_mask);
 	if (!volumes)
 		goto out_free_scratch;

 	for (i = 0; i < nr_volumes; i++) {
 		ret = nfs4_block_decode_volume(&xdr, &volumes[i]);
 		if (ret < 0)
 			goto out_free_volumes;
 	}

 	top = kzalloc(sizeof(*top), gfp_mask);
 	if (!top)
 		goto out_free_volumes;

 	ret = bl_parse_deviceid(server, top, volumes, nr_volumes - 1, gfp_mask);
 	if (ret) {
 		bl_free_device(top);
 		kfree(top);
 		goto out_free_volumes;
 	}

 	node = &top->node;
 	nfs4_init_deviceid_node(node, server, &pdev->dev_id);

 out_free_volumes:
 	kfree(volumes);
 out_free_scratch:
 	__free_page(scratch);
 out:
 	return node;
 }
	/*
	* Copyright (c) 2014-2016 Christoph Hellwig.
	*/
	#include <linux/sunrpc/svc.h>
	#include <linux/blkdev.h>
	#include <linux/nfs4.h>
	#include <linux/nfs_fs.h>
	#include <linux/nfs_xdr.h>
	#include <linux/pr.h>

	#include "blocklayout.h"

	#define NFSDBG_FACILITY NFSDBG_PNFS_LD

	static void
	bl_free_device(struct pnfs_block_dev *dev)
	{
	if (dev->nr_children) {
	int i;

	for (i = 0; i < dev->nr_children; i++)
	bl_free_device(&dev->children[i]);
	kfree(dev->children);
	} else {
	if (dev->pr_registered) {
	const struct pr_ops *ops =
	dev->bdev->bd_disk->fops->pr_ops;
	int error;

	error = ops->pr_register(dev->bdev, dev->pr_key, 0,
	false);
	if (error)
	pr_err("failed to unregister PR key.\n");
	}

	if (dev->bdev)
	blkdev_put(dev->bdev, FMODE_READ \| FMODE_WRITE);
	}
	}

	void
	bl_free_deviceid_node(struct nfs4_deviceid_node *d)
	{
	struct pnfs_block_dev *dev =
	container_of(d, struct pnfs_block_dev, node);

	bl_free_device(dev);
	kfree_rcu(dev, node.rcu);
	}

	static int
	nfs4_block_decode_volume(struct xdr_stream xdr, struct pnfs_block_volume b)
	{
	__be32 *p;
	int i;

	p = xdr_inline_decode(xdr, 4);
	if (!p)
	return -EIO;
	b->type = be32_to_cpup(p++);

	switch (b->type) {
	case PNFS_BLOCK_VOLUME_SIMPLE:
	p = xdr_inline_decode(xdr, 4);
	if (!p)
	return -EIO;
	b->simple.nr_sigs = be32_to_cpup(p++);
	if (!b->simple.nr_sigs \|\| b->simple.nr_sigs > PNFS_BLOCK_MAX_UUIDS) {
	dprintk("Bad signature count: %d\n", b->simple.nr_sigs);
	return -EIO;
	}

	b->simple.len = 4 + 4;
	for (i = 0; i < b->simple.nr_sigs; i++) {
	p = xdr_inline_decode(xdr, 8 + 4);
	if (!p)
	return -EIO;
	p = xdr_decode_hyper(p, &b->simple.sigs[i].offset);
	b->simple.sigs[i].sig_len = be32_to_cpup(p++);
	if (b->simple.sigs[i].sig_len > PNFS_BLOCK_UUID_LEN) {
	pr_info("signature too long: %d\n",
	b->simple.sigs[i].sig_len);
	return -EIO;
	}

	p = xdr_inline_decode(xdr, b->simple.sigs[i].sig_len);
	if (!p)
	return -EIO;
	memcpy(&b->simple.sigs[i].sig, p,
	b->simple.sigs[i].sig_len);

	b->simple.len += 8 + 4 + \
	(XDR_QUADLEN(b->simple.sigs[i].sig_len) << 2);
	}
	break;
	case PNFS_BLOCK_VOLUME_SLICE:
	p = xdr_inline_decode(xdr, 8 + 8 + 4);
	if (!p)
	return -EIO;
	p = xdr_decode_hyper(p, &b->slice.start);
	p = xdr_decode_hyper(p, &b->slice.len);
	b->slice.volume = be32_to_cpup(p++);
	break;
	case PNFS_BLOCK_VOLUME_CONCAT:
	p = xdr_inline_decode(xdr, 4);
	if (!p)
	return -EIO;

	b->concat.volumes_count = be32_to_cpup(p++);
	if (b->concat.volumes_count > PNFS_BLOCK_MAX_DEVICES) {
	dprintk("Too many volumes: %d\n", b->concat.volumes_count);
	return -EIO;
	}

	p = xdr_inline_decode(xdr, b->concat.volumes_count * 4);
	if (!p)
	return -EIO;
	for (i = 0; i < b->concat.volumes_count; i++)
	b->concat.volumes[i] = be32_to_cpup(p++);
	break;
	case PNFS_BLOCK_VOLUME_STRIPE:
	p = xdr_inline_decode(xdr, 8 + 4);
	if (!p)
	return -EIO;

	p = xdr_decode_hyper(p, &b->stripe.chunk_size);
	b->stripe.volumes_count = be32_to_cpup(p++);
	if (b->stripe.volumes_count > PNFS_BLOCK_MAX_DEVICES) {
	dprintk("Too many volumes: %d\n", b->stripe.volumes_count);
	return -EIO;
	}

	p = xdr_inline_decode(xdr, b->stripe.volumes_count * 4);
	if (!p)
	return -EIO;
	for (i = 0; i < b->stripe.volumes_count; i++)
	b->stripe.volumes[i] = be32_to_cpup(p++);
	break;
	case PNFS_BLOCK_VOLUME_SCSI:
	p = xdr_inline_decode(xdr, 4 + 4 + 4);
	if (!p)
	return -EIO;
	b->scsi.code_set = be32_to_cpup(p++);
	b->scsi.designator_type = be32_to_cpup(p++);
	b->scsi.designator_len = be32_to_cpup(p++);
	p = xdr_inline_decode(xdr, b->scsi.designator_len);
	if (!p)
	return -EIO;
	if (b->scsi.designator_len > 256)
	return -EIO;
	memcpy(&b->scsi.designator, p, b->scsi.designator_len);
	p = xdr_inline_decode(xdr, 8);
	if (!p)
	return -EIO;
	p = xdr_decode_hyper(p, &b->scsi.pr_key);
	break;
	default:
	dprintk("unknown volume type!\n");
	return -EIO;
	}

	return 0;
	}

	static bool bl_map_simple(struct pnfs_block_dev *dev, u64 offset,
	struct pnfs_block_dev_map *map)
	{
	map->start = dev->start;
	map->len = dev->len;
	map->disk_offset = dev->disk_offset;
	map->bdev = dev->bdev;
	return true;
	}

	static bool bl_map_concat(struct pnfs_block_dev *dev, u64 offset,
	struct pnfs_block_dev_map *map)
	{
	int i;

	for (i = 0; i < dev->nr_children; i++) {
	struct pnfs_block_dev *child = &dev->children[i];

	if (child->start > offset \|\|
	child->start + child->len <= offset)
	continue;

	child->map(child, offset - child->start, map);
	return true;
	}

	dprintk("%s: ran off loop!\n", __func__);
	return false;
	}

	static bool bl_map_stripe(struct pnfs_block_dev *dev, u64 offset,
	struct pnfs_block_dev_map *map)
	{
	struct pnfs_block_dev *child;
	u64 chunk;
	u32 chunk_idx;
	u64 disk_offset;

	chunk = div_u64(offset, dev->chunk_size);
	div_u64_rem(chunk, dev->nr_children, &chunk_idx);

	if (chunk_idx >= dev->nr_children) {
	dprintk("%s: invalid chunk idx %d (%lld/%lld)\n",
	__func__, chunk_idx, offset, dev->chunk_size);
	/* error, should not happen */
	return false;
	}

	/* truncate offset to the beginning of the stripe */
	offset = chunk * dev->chunk_size;

	/* disk offset of the stripe */
	disk_offset = div_u64(offset, dev->nr_children);

	child = &dev->children[chunk_idx];
	child->map(child, disk_offset, map);

	map->start += offset;
	map->disk_offset += disk_offset;
	map->len = dev->chunk_size;
	return true;
	}

	static int
	bl_parse_deviceid(struct nfs_server server, struct pnfs_block_dev d,
	struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask);


	static int
	bl_parse_simple(struct nfs_server server, struct pnfs_block_dev d,
	struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
	{
	struct pnfs_block_volume *v = &volumes[idx];
	struct block_device *bdev;
	dev_t dev;

	dev = bl_resolve_deviceid(server, v, gfp_mask);
	if (!dev)
	return -EIO;

	bdev = blkdev_get_by_dev(dev, FMODE_READ \| FMODE_WRITE, NULL);
	if (IS_ERR(bdev)) {
	printk(KERN_WARNING "pNFS: failed to open device %d:%d (%ld)\n",
	MAJOR(dev), MINOR(dev), PTR_ERR(bdev));
	return PTR_ERR(bdev);
	}
	d->bdev = bdev;


	d->len = i_size_read(d->bdev->bd_inode);
	d->map = bl_map_simple;

	printk(KERN_INFO "pNFS: using block device %s\n",
	d->bdev->bd_disk->disk_name);
	return 0;
	}

	static bool
	bl_validate_designator(struct pnfs_block_volume *v)
	{
	switch (v->scsi.designator_type) {
	case PS_DESIGNATOR_EUI64:
	if (v->scsi.code_set != PS_CODE_SET_BINARY)
	return false;

	if (v->scsi.designator_len != 8 &&
	v->scsi.designator_len != 10 &&
	v->scsi.designator_len != 16)
	return false;

	return true;
	case PS_DESIGNATOR_NAA:
	if (v->scsi.code_set != PS_CODE_SET_BINARY)
	return false;

	if (v->scsi.designator_len != 8 &&
	v->scsi.designator_len != 16)
	return false;

	return true;
	case PS_DESIGNATOR_T10:
	case PS_DESIGNATOR_NAME:
	pr_err("pNFS: unsupported designator "
	"(code set %d, type %d, len %d.\n",
	v->scsi.code_set,
	v->scsi.designator_type,
	v->scsi.designator_len);
	return false;
	default:
	pr_err("pNFS: invalid designator "
	"(code set %d, type %d, len %d.\n",
	v->scsi.code_set,
	v->scsi.designator_type,
	v->scsi.designator_len);
	return false;
	}
	}

	/*
	* Try to open the udev path for the WWN. At least on Debian the udev
	* by-id path will always point to the dm-multipath device if one exists.
	*/
	static struct block_device *
	bl_open_udev_path(struct pnfs_block_volume *v)
	{
	struct block_device *bdev;
	const char *devname;

	devname = kasprintf(GFP_KERNEL, "/dev/disk/by-id/wwn-0x%*phN",
	v->scsi.designator_len, v->scsi.designator);
	if (!devname)
	return ERR_PTR(-ENOMEM);

	bdev = blkdev_get_by_path(devname, FMODE_READ \| FMODE_WRITE, NULL);
	if (IS_ERR(bdev)) {
	pr_warn("pNFS: failed to open device %s (%ld)\n",
	devname, PTR_ERR(bdev));
	}

	kfree(devname);
	return bdev;
	}

	/*
	* Try to open the RH/Fedora specific dm-mpath udev path for this WWN, as the
	* wwn- links will only point to the first discovered SCSI device there.
	*/
	static struct block_device *
	bl_open_dm_mpath_udev_path(struct pnfs_block_volume *v)
	{
	struct block_device *bdev;
	const char *devname;

	devname = kasprintf(GFP_KERNEL,
	"/dev/disk/by-id/dm-uuid-mpath-%d%*phN",
	v->scsi.designator_type,
	v->scsi.designator_len, v->scsi.designator);
	if (!devname)
	return ERR_PTR(-ENOMEM);

	bdev = blkdev_get_by_path(devname, FMODE_READ \| FMODE_WRITE, NULL);
	kfree(devname);
	return bdev;
	}

	static int
	bl_parse_scsi(struct nfs_server server, struct pnfs_block_dev d,
	struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
	{
	struct pnfs_block_volume *v = &volumes[idx];
	struct block_device *bdev;
	const struct pr_ops *ops;
	int error;

	if (!bl_validate_designator(v))
	return -EINVAL;

	bdev = bl_open_dm_mpath_udev_path(v);
	if (IS_ERR(bdev))
	bdev = bl_open_udev_path(v);
	if (IS_ERR(bdev))
	return PTR_ERR(bdev);
	d->bdev = bdev;

	d->len = i_size_read(d->bdev->bd_inode);
	d->map = bl_map_simple;
	d->pr_key = v->scsi.pr_key;

	pr_info("pNFS: using block device %s (reservation key 0x%llx)\n",
	d->bdev->bd_disk->disk_name, d->pr_key);

	ops = d->bdev->bd_disk->fops->pr_ops;
	if (!ops) {
	pr_err("pNFS: block device %s does not support reservations.",
	d->bdev->bd_disk->disk_name);
	error = -EINVAL;
	goto out_blkdev_put;
	}

	error = ops->pr_register(d->bdev, 0, d->pr_key, true);
	if (error) {
	pr_err("pNFS: failed to register key for block device %s.",
	d->bdev->bd_disk->disk_name);
	goto out_blkdev_put;
	}

	d->pr_registered = true;
	return 0;

	out_blkdev_put:
	blkdev_put(d->bdev, FMODE_READ \| FMODE_WRITE);
	return error;
	}

	static int
	bl_parse_slice(struct nfs_server server, struct pnfs_block_dev d,
	struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
	{
	struct pnfs_block_volume *v = &volumes[idx];
	int ret;

	ret = bl_parse_deviceid(server, d, volumes, v->slice.volume, gfp_mask);
	if (ret)
	return ret;

	d->disk_offset = v->slice.start;
	d->len = v->slice.len;
	return 0;
	}

	static int
	bl_parse_concat(struct nfs_server server, struct pnfs_block_dev d,
	struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
	{
	struct pnfs_block_volume *v = &volumes[idx];
	u64 len = 0;
	int ret, i;

	d->children = kcalloc(v->concat.volumes_count,
	sizeof(struct pnfs_block_dev), GFP_KERNEL);
	if (!d->children)
	return -ENOMEM;

	for (i = 0; i < v->concat.volumes_count; i++) {
	ret = bl_parse_deviceid(server, &d->children[i],
	volumes, v->concat.volumes[i], gfp_mask);
	if (ret)
	return ret;

	d->nr_children++;
	d->children[i].start += len;
	len += d->children[i].len;
	}

	d->len = len;
	d->map = bl_map_concat;
	return 0;
	}

	static int
	bl_parse_stripe(struct nfs_server server, struct pnfs_block_dev d,
	struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
	{
	struct pnfs_block_volume *v = &volumes[idx];
	u64 len = 0;
	int ret, i;

	d->children = kcalloc(v->stripe.volumes_count,
	sizeof(struct pnfs_block_dev), GFP_KERNEL);
	if (!d->children)
	return -ENOMEM;

	for (i = 0; i < v->stripe.volumes_count; i++) {
	ret = bl_parse_deviceid(server, &d->children[i],
	volumes, v->stripe.volumes[i], gfp_mask);
	if (ret)
	return ret;

	d->nr_children++;
	len += d->children[i].len;
	}

	d->len = len;
	d->chunk_size = v->stripe.chunk_size;
	d->map = bl_map_stripe;
	return 0;
	}

	static int
	bl_parse_deviceid(struct nfs_server server, struct pnfs_block_dev d,
	struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
	{
	switch (volumes[idx].type) {
	case PNFS_BLOCK_VOLUME_SIMPLE:
	return bl_parse_simple(server, d, volumes, idx, gfp_mask);
	case PNFS_BLOCK_VOLUME_SLICE:
	return bl_parse_slice(server, d, volumes, idx, gfp_mask);
	case PNFS_BLOCK_VOLUME_CONCAT:
	return bl_parse_concat(server, d, volumes, idx, gfp_mask);
	case PNFS_BLOCK_VOLUME_STRIPE:
	return bl_parse_stripe(server, d, volumes, idx, gfp_mask);
	case PNFS_BLOCK_VOLUME_SCSI:
	return bl_parse_scsi(server, d, volumes, idx, gfp_mask);
	default:
	dprintk("unsupported volume type: %d\n", volumes[idx].type);
	return -EIO;
	}
	}

	struct nfs4_deviceid_node *
	bl_alloc_deviceid_node(struct nfs_server server, struct pnfs_device pdev,
	gfp_t gfp_mask)
	{
	struct nfs4_deviceid_node *node = NULL;
	struct pnfs_block_volume *volumes;
	struct pnfs_block_dev *top;
	struct xdr_stream xdr;
	struct xdr_buf buf;
	struct page *scratch;
	int nr_volumes, ret, i;
	__be32 *p;

	scratch = alloc_page(gfp_mask);
	if (!scratch)
	goto out;

	xdr_init_decode_pages(&xdr, &buf, pdev->pages, pdev->pglen);
	xdr_set_scratch_buffer(&xdr, page_address(scratch), PAGE_SIZE);

	p = xdr_inline_decode(&xdr, sizeof(__be32));
	if (!p)
	goto out_free_scratch;
	nr_volumes = be32_to_cpup(p++);

	volumes = kcalloc(nr_volumes, sizeof(struct pnfs_block_volume),
	gfp_mask);
	if (!volumes)
	goto out_free_scratch;

	for (i = 0; i < nr_volumes; i++) {
	ret = nfs4_block_decode_volume(&xdr, &volumes[i]);
	if (ret < 0)
	goto out_free_volumes;
	}

	top = kzalloc(sizeof(*top), gfp_mask);
	if (!top)
	goto out_free_volumes;

	ret = bl_parse_deviceid(server, top, volumes, nr_volumes - 1, gfp_mask);
	if (ret) {
	bl_free_device(top);
	kfree(top);
	goto out_free_volumes;
	}

	node = &top->node;
	nfs4_init_deviceid_node(node, server, &pdev->dev_id);

	out_free_volumes:
	kfree(volumes);
	out_free_scratch:
	__free_page(scratch);
	out:
	return node;
	}