volumes.c 32.3 KB
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/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */
#include <linux/sched.h>
#include <linux/bio.h>
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#include <linux/buffer_head.h>
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#include <asm/div64.h>
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#include "ctree.h"
#include "extent_map.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#include "volumes.h"

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struct map_lookup {
	u64 type;
	int io_align;
	int io_width;
	int stripe_len;
	int sector_size;
	int num_stripes;
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	struct btrfs_bio_stripe stripes[];
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};

#define map_lookup_size(n) (sizeof(struct map_lookup) + \
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			    (sizeof(struct btrfs_bio_stripe) * (n)))
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static DEFINE_MUTEX(uuid_mutex);
static LIST_HEAD(fs_uuids);

int btrfs_cleanup_fs_uuids(void)
{
	struct btrfs_fs_devices *fs_devices;
	struct list_head *uuid_cur;
	struct list_head *devices_cur;
	struct btrfs_device *dev;

	list_for_each(uuid_cur, &fs_uuids) {
		fs_devices = list_entry(uuid_cur, struct btrfs_fs_devices,
					list);
		while(!list_empty(&fs_devices->devices)) {
			devices_cur = fs_devices->devices.next;
			dev = list_entry(devices_cur, struct btrfs_device,
					 dev_list);
			printk("uuid cleanup finds %s\n", dev->name);
			if (dev->bdev) {
				printk("closing\n");
				close_bdev_excl(dev->bdev);
			}
			list_del(&dev->dev_list);
			kfree(dev);
		}
	}
	return 0;
}

static struct btrfs_device *__find_device(struct list_head *head, u64 devid)
{
	struct btrfs_device *dev;
	struct list_head *cur;

	list_for_each(cur, head) {
		dev = list_entry(cur, struct btrfs_device, dev_list);
		if (dev->devid == devid)
			return dev;
	}
	return NULL;
}

static struct btrfs_fs_devices *find_fsid(u8 *fsid)
{
	struct list_head *cur;
	struct btrfs_fs_devices *fs_devices;

	list_for_each(cur, &fs_uuids) {
		fs_devices = list_entry(cur, struct btrfs_fs_devices, list);
		if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
			return fs_devices;
	}
	return NULL;
}

static int device_list_add(const char *path,
			   struct btrfs_super_block *disk_super,
			   u64 devid, struct btrfs_fs_devices **fs_devices_ret)
{
	struct btrfs_device *device;
	struct btrfs_fs_devices *fs_devices;
	u64 found_transid = btrfs_super_generation(disk_super);

	fs_devices = find_fsid(disk_super->fsid);
	if (!fs_devices) {
		fs_devices = kmalloc(sizeof(*fs_devices), GFP_NOFS);
		if (!fs_devices)
			return -ENOMEM;
		INIT_LIST_HEAD(&fs_devices->devices);
		list_add(&fs_devices->list, &fs_uuids);
		memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
		fs_devices->latest_devid = devid;
		fs_devices->latest_trans = found_transid;
		fs_devices->lowest_devid = (u64)-1;
		fs_devices->num_devices = 0;
		device = NULL;
	} else {
		device = __find_device(&fs_devices->devices, devid);
	}
	if (!device) {
		device = kzalloc(sizeof(*device), GFP_NOFS);
		if (!device) {
			/* we can safely leave the fs_devices entry around */
			return -ENOMEM;
		}
		device->devid = devid;
		device->name = kstrdup(path, GFP_NOFS);
		if (!device->name) {
			kfree(device);
			return -ENOMEM;
		}
		list_add(&device->dev_list, &fs_devices->devices);
		fs_devices->num_devices++;
	}

	if (found_transid > fs_devices->latest_trans) {
		fs_devices->latest_devid = devid;
		fs_devices->latest_trans = found_transid;
	}
	if (fs_devices->lowest_devid > devid) {
		fs_devices->lowest_devid = devid;
		printk("lowest devid now %Lu\n", devid);
	}
	*fs_devices_ret = fs_devices;
	return 0;
}

int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
	struct list_head *head = &fs_devices->devices;
	struct list_head *cur;
	struct btrfs_device *device;

	mutex_lock(&uuid_mutex);
	list_for_each(cur, head) {
		device = list_entry(cur, struct btrfs_device, dev_list);
		if (device->bdev) {
			close_bdev_excl(device->bdev);
			printk("close devices closes %s\n", device->name);
		}
		device->bdev = NULL;
	}
	mutex_unlock(&uuid_mutex);
	return 0;
}

int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
		       int flags, void *holder)
{
	struct block_device *bdev;
	struct list_head *head = &fs_devices->devices;
	struct list_head *cur;
	struct btrfs_device *device;
	int ret;

	mutex_lock(&uuid_mutex);
	list_for_each(cur, head) {
		device = list_entry(cur, struct btrfs_device, dev_list);
		bdev = open_bdev_excl(device->name, flags, holder);
printk("opening %s devid %Lu\n", device->name, device->devid);
		if (IS_ERR(bdev)) {
			printk("open %s failed\n", device->name);
			ret = PTR_ERR(bdev);
			goto fail;
		}
		if (device->devid == fs_devices->latest_devid)
			fs_devices->latest_bdev = bdev;
		if (device->devid == fs_devices->lowest_devid) {
			fs_devices->lowest_bdev = bdev;
printk("lowest bdev %s\n", device->name);
		}
		device->bdev = bdev;
	}
	mutex_unlock(&uuid_mutex);
	return 0;
fail:
	mutex_unlock(&uuid_mutex);
	btrfs_close_devices(fs_devices);
	return ret;
}

int btrfs_scan_one_device(const char *path, int flags, void *holder,
			  struct btrfs_fs_devices **fs_devices_ret)
{
	struct btrfs_super_block *disk_super;
	struct block_device *bdev;
	struct buffer_head *bh;
	int ret;
	u64 devid;

	mutex_lock(&uuid_mutex);

	printk("scan one opens %s\n", path);
	bdev = open_bdev_excl(path, flags, holder);

	if (IS_ERR(bdev)) {
		printk("open failed\n");
		ret = PTR_ERR(bdev);
		goto error;
	}

	ret = set_blocksize(bdev, 4096);
	if (ret)
		goto error_close;
	bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
	if (!bh) {
		ret = -EIO;
		goto error_close;
	}
	disk_super = (struct btrfs_super_block *)bh->b_data;
	if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
	    sizeof(disk_super->magic))) {
		printk("no btrfs found on %s\n", path);
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		ret = -EINVAL;
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		goto error_brelse;
	}
	devid = le64_to_cpu(disk_super->dev_item.devid);
	printk("found device %Lu on %s\n", devid, path);
	ret = device_list_add(path, disk_super, devid, fs_devices_ret);

error_brelse:
	brelse(bh);
error_close:
	close_bdev_excl(bdev);
	printk("scan one closes bdev %s\n", path);
error:
	mutex_unlock(&uuid_mutex);
	return ret;
}
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/*
 * this uses a pretty simple search, the expectation is that it is
 * called very infrequently and that a given device has a small number
 * of extents
 */
static int find_free_dev_extent(struct btrfs_trans_handle *trans,
				struct btrfs_device *device,
				struct btrfs_path *path,
				u64 num_bytes, u64 *start)
{
	struct btrfs_key key;
	struct btrfs_root *root = device->dev_root;
	struct btrfs_dev_extent *dev_extent = NULL;
	u64 hole_size = 0;
	u64 last_byte = 0;
	u64 search_start = 0;
	u64 search_end = device->total_bytes;
	int ret;
	int slot = 0;
	int start_found;
	struct extent_buffer *l;

	start_found = 0;
	path->reada = 2;

	/* FIXME use last free of some kind */

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	/* we don't want to overwrite the superblock on the drive,
	 * so we make sure to start at an offset of at least 1MB
	 */
	search_start = max((u64)1024 * 1024, search_start);
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	key.objectid = device->devid;
	key.offset = search_start;
	key.type = BTRFS_DEV_EXTENT_KEY;
	ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
	if (ret < 0)
		goto error;
	ret = btrfs_previous_item(root, path, 0, key.type);
	if (ret < 0)
		goto error;
	l = path->nodes[0];
	btrfs_item_key_to_cpu(l, &key, path->slots[0]);
	while (1) {
		l = path->nodes[0];
		slot = path->slots[0];
		if (slot >= btrfs_header_nritems(l)) {
			ret = btrfs_next_leaf(root, path);
			if (ret == 0)
				continue;
			if (ret < 0)
				goto error;
no_more_items:
			if (!start_found) {
				if (search_start >= search_end) {
					ret = -ENOSPC;
					goto error;
				}
				*start = search_start;
				start_found = 1;
				goto check_pending;
			}
			*start = last_byte > search_start ?
				last_byte : search_start;
			if (search_end <= *start) {
				ret = -ENOSPC;
				goto error;
			}
			goto check_pending;
		}
		btrfs_item_key_to_cpu(l, &key, slot);

		if (key.objectid < device->devid)
			goto next;

		if (key.objectid > device->devid)
			goto no_more_items;

		if (key.offset >= search_start && key.offset > last_byte &&
		    start_found) {
			if (last_byte < search_start)
				last_byte = search_start;
			hole_size = key.offset - last_byte;
			if (key.offset > last_byte &&
			    hole_size >= num_bytes) {
				*start = last_byte;
				goto check_pending;
			}
		}
		if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) {
			goto next;
		}

		start_found = 1;
		dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
		last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
next:
		path->slots[0]++;
		cond_resched();
	}
check_pending:
	/* we have to make sure we didn't find an extent that has already
	 * been allocated by the map tree or the original allocation
	 */
	btrfs_release_path(root, path);
	BUG_ON(*start < search_start);

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	if (*start + num_bytes > search_end) {
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		ret = -ENOSPC;
		goto error;
	}
	/* check for pending inserts here */
	return 0;

error:
	btrfs_release_path(root, path);
	return ret;
}

int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
			   struct btrfs_device *device,
			   u64 owner, u64 num_bytes, u64 *start)
{
	int ret;
	struct btrfs_path *path;
	struct btrfs_root *root = device->dev_root;
	struct btrfs_dev_extent *extent;
	struct extent_buffer *leaf;
	struct btrfs_key key;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	ret = find_free_dev_extent(trans, device, path, num_bytes, start);
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	if (ret) {
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		goto err;
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	}
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	key.objectid = device->devid;
	key.offset = *start;
	key.type = BTRFS_DEV_EXTENT_KEY;
	ret = btrfs_insert_empty_item(trans, root, path, &key,
				      sizeof(*extent));
	BUG_ON(ret);

	leaf = path->nodes[0];
	extent = btrfs_item_ptr(leaf, path->slots[0],
				struct btrfs_dev_extent);
	btrfs_set_dev_extent_owner(leaf, extent, owner);
	btrfs_set_dev_extent_length(leaf, extent, num_bytes);
	btrfs_mark_buffer_dirty(leaf);
err:
	btrfs_free_path(path);
	return ret;
}

static int find_next_chunk(struct btrfs_root *root, u64 *objectid)
{
	struct btrfs_path *path;
	int ret;
	struct btrfs_key key;
	struct btrfs_key found_key;

	path = btrfs_alloc_path();
	BUG_ON(!path);

	key.objectid = (u64)-1;
	key.offset = (u64)-1;
	key.type = BTRFS_CHUNK_ITEM_KEY;

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto error;

	BUG_ON(ret == 0);

	ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
	if (ret) {
		*objectid = 0;
	} else {
		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
				      path->slots[0]);
		*objectid = found_key.objectid + found_key.offset;
	}
	ret = 0;
error:
	btrfs_free_path(path);
	return ret;
}

static int find_next_devid(struct btrfs_root *root, struct btrfs_path *path,
			   u64 *objectid)
{
	int ret;
	struct btrfs_key key;
	struct btrfs_key found_key;

	key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
	key.type = BTRFS_DEV_ITEM_KEY;
	key.offset = (u64)-1;

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto error;

	BUG_ON(ret == 0);

	ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
				  BTRFS_DEV_ITEM_KEY);
	if (ret) {
		*objectid = 1;
	} else {
		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
				      path->slots[0]);
		*objectid = found_key.offset + 1;
	}
	ret = 0;
error:
	btrfs_release_path(root, path);
	return ret;
}

/*
 * the device information is stored in the chunk root
 * the btrfs_device struct should be fully filled in
 */
int btrfs_add_device(struct btrfs_trans_handle *trans,
		     struct btrfs_root *root,
		     struct btrfs_device *device)
{
	int ret;
	struct btrfs_path *path;
	struct btrfs_dev_item *dev_item;
	struct extent_buffer *leaf;
	struct btrfs_key key;
	unsigned long ptr;
	u64 free_devid;

	root = root->fs_info->chunk_root;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	ret = find_next_devid(root, path, &free_devid);
	if (ret)
		goto out;

	key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
	key.type = BTRFS_DEV_ITEM_KEY;
	key.offset = free_devid;

	ret = btrfs_insert_empty_item(trans, root, path, &key,
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				      sizeof(*dev_item));
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	if (ret)
		goto out;

	leaf = path->nodes[0];
	dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);

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	device->devid = free_devid;
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	btrfs_set_device_id(leaf, dev_item, device->devid);
	btrfs_set_device_type(leaf, dev_item, device->type);
	btrfs_set_device_io_align(leaf, dev_item, device->io_align);
	btrfs_set_device_io_width(leaf, dev_item, device->io_width);
	btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
	btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
	btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);

	ptr = (unsigned long)btrfs_device_uuid(dev_item);
	write_extent_buffer(leaf, device->uuid, ptr, BTRFS_DEV_UUID_SIZE);
	btrfs_mark_buffer_dirty(leaf);
	ret = 0;

out:
	btrfs_free_path(path);
	return ret;
}
int btrfs_update_device(struct btrfs_trans_handle *trans,
			struct btrfs_device *device)
{
	int ret;
	struct btrfs_path *path;
	struct btrfs_root *root;
	struct btrfs_dev_item *dev_item;
	struct extent_buffer *leaf;
	struct btrfs_key key;

	root = device->dev_root->fs_info->chunk_root;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
	key.type = BTRFS_DEV_ITEM_KEY;
	key.offset = device->devid;

	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
	if (ret < 0)
		goto out;

	if (ret > 0) {
		ret = -ENOENT;
		goto out;
	}

	leaf = path->nodes[0];
	dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);

	btrfs_set_device_id(leaf, dev_item, device->devid);
	btrfs_set_device_type(leaf, dev_item, device->type);
	btrfs_set_device_io_align(leaf, dev_item, device->io_align);
	btrfs_set_device_io_width(leaf, dev_item, device->io_width);
	btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
	btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
	btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
	btrfs_mark_buffer_dirty(leaf);

out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
			   struct btrfs_root *root,
			   struct btrfs_key *key,
			   struct btrfs_chunk *chunk, int item_size)
{
	struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
	struct btrfs_disk_key disk_key;
	u32 array_size;
	u8 *ptr;

	array_size = btrfs_super_sys_array_size(super_copy);
	if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
		return -EFBIG;

	ptr = super_copy->sys_chunk_array + array_size;
	btrfs_cpu_key_to_disk(&disk_key, key);
	memcpy(ptr, &disk_key, sizeof(disk_key));
	ptr += sizeof(disk_key);
	memcpy(ptr, chunk, item_size);
	item_size += sizeof(disk_key);
	btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
	return 0;
}

int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
		      struct btrfs_root *extent_root, u64 *start,
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		      u64 *num_bytes, u64 type)
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{
	u64 dev_offset;
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	struct btrfs_fs_info *info = extent_root->fs_info;
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	struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
	struct btrfs_stripe *stripes;
	struct btrfs_device *device = NULL;
	struct btrfs_chunk *chunk;
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	struct list_head private_devs;
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	struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices;
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	struct list_head *cur;
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	struct extent_map_tree *em_tree;
	struct map_lookup *map;
	struct extent_map *em;
	u64 physical;
	u64 calc_size = 1024 * 1024 * 1024;
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	u64 min_free = calc_size;
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	u64 avail;
	u64 max_avail = 0;
	int num_stripes = 1;
	int looped = 0;
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	int ret;
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	int index;
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	int stripe_len = 64 * 1024;
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	struct btrfs_key key;

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	if (list_empty(dev_list))
		return -ENOSPC;
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	if (type & (BTRFS_BLOCK_GROUP_RAID0))
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		num_stripes = btrfs_super_num_devices(&info->super_copy);
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	if (type & (BTRFS_BLOCK_GROUP_DUP))
		num_stripes = 2;
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	if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
		num_stripes = min_t(u64, 2,
				  btrfs_super_num_devices(&info->super_copy));
	}
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again:
	INIT_LIST_HEAD(&private_devs);
	cur = dev_list->next;
	index = 0;
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	if (type & BTRFS_BLOCK_GROUP_DUP)
		min_free = calc_size * 2;

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	/* build a private list of devices we will allocate from */
	while(index < num_stripes) {
		device = list_entry(cur, struct btrfs_device, dev_list);
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		avail = device->total_bytes - device->bytes_used;
		cur = cur->next;
		if (avail > max_avail)
			max_avail = avail;
655
		if (avail >= min_free) {
656 657
			list_move_tail(&device->dev_list, &private_devs);
			index++;
658 659
			if (type & BTRFS_BLOCK_GROUP_DUP)
				index++;
660 661 662 663 664 665 666 667 668 669 670 671 672
		}
		if (cur == dev_list)
			break;
	}
	if (index < num_stripes) {
		list_splice(&private_devs, dev_list);
		if (!looped && max_avail > 0) {
			looped = 1;
			calc_size = max_avail;
			goto again;
		}
		return -ENOSPC;
	}
673 674 675 676 677 678 679 680 681

	ret = find_next_chunk(chunk_root, &key.objectid);
	if (ret)
		return ret;

	chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
	if (!chunk)
		return -ENOMEM;

682 683 684 685 686 687
	map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
	if (!map) {
		kfree(chunk);
		return -ENOMEM;
	}

688 689
	stripes = &chunk->stripe;

690
	if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
691 692 693 694
		*num_bytes = calc_size;
	else
		*num_bytes = calc_size * num_stripes;

695
	index = 0;
696
printk("new chunk type %Lu start %Lu size %Lu\n", type, key.objectid, *num_bytes);
697
	while(index < num_stripes) {
698 699 700
		BUG_ON(list_empty(&private_devs));
		cur = private_devs.next;
		device = list_entry(cur, struct btrfs_device, dev_list);
701 702 703 704 705

		/* loop over this device again if we're doing a dup group */
		if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
		    (index == num_stripes - 1))
			list_move_tail(&device->dev_list, dev_list);
706 707 708 709 710

		ret = btrfs_alloc_dev_extent(trans, device,
					     key.objectid,
					     calc_size, &dev_offset);
		BUG_ON(ret);
711
printk("alloc chunk start %Lu size %Lu from dev %Lu type %Lu\n", key.objectid, calc_size, device->devid, type);
712 713 714 715
		device->bytes_used += calc_size;
		ret = btrfs_update_device(trans, device);
		BUG_ON(ret);

716 717
		map->stripes[index].dev = device;
		map->stripes[index].physical = dev_offset;
718 719 720 721 722
		btrfs_set_stack_stripe_devid(stripes + index, device->devid);
		btrfs_set_stack_stripe_offset(stripes + index, dev_offset);
		physical = dev_offset;
		index++;
	}
723
	BUG_ON(!list_empty(&private_devs));
724 725 726 727 728

	/* key.objectid was set above */
	key.offset = *num_bytes;
	key.type = BTRFS_CHUNK_ITEM_KEY;
	btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
729
	btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
730 731
	btrfs_set_stack_chunk_type(chunk, type);
	btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
732 733
	btrfs_set_stack_chunk_io_align(chunk, stripe_len);
	btrfs_set_stack_chunk_io_width(chunk, stripe_len);
734
	btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
735 736 737 738 739 740
	map->sector_size = extent_root->sectorsize;
	map->stripe_len = stripe_len;
	map->io_align = stripe_len;
	map->io_width = stripe_len;
	map->type = type;
	map->num_stripes = num_stripes;
741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790

	ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
				btrfs_chunk_item_size(num_stripes));
	BUG_ON(ret);
	*start = key.objectid;

	em = alloc_extent_map(GFP_NOFS);
	if (!em)
		return -ENOMEM;
	em->bdev = (struct block_device *)map;
	em->start = key.objectid;
	em->len = key.offset;
	em->block_start = 0;

	kfree(chunk);

	em_tree = &extent_root->fs_info->mapping_tree.map_tree;
	spin_lock(&em_tree->lock);
	ret = add_extent_mapping(em_tree, em);
	BUG_ON(ret);
	spin_unlock(&em_tree->lock);
	free_extent_map(em);
	return ret;
}

void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
{
	extent_map_tree_init(&tree->map_tree, GFP_NOFS);
}

void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
{
	struct extent_map *em;

	while(1) {
		spin_lock(&tree->map_tree.lock);
		em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
		if (em)
			remove_extent_mapping(&tree->map_tree, em);
		spin_unlock(&tree->map_tree.lock);
		if (!em)
			break;
		kfree(em->bdev);
		/* once for us */
		free_extent_map(em);
		/* once for the tree */
		free_extent_map(em);
	}
}

791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812
int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
{
	struct extent_map *em;
	struct map_lookup *map;
	struct extent_map_tree *em_tree = &map_tree->map_tree;
	int ret;

	spin_lock(&em_tree->lock);
	em = lookup_extent_mapping(em_tree, logical, len);
	BUG_ON(!em);

	BUG_ON(em->start > logical || em->start + em->len < logical);
	map = (struct map_lookup *)em->bdev;
	if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
		ret = map->num_stripes;
	else
		ret = 1;
	free_extent_map(em);
	spin_unlock(&em_tree->lock);
	return ret;
}

813
int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
814
		    u64 logical, u64 *length,
815
		    struct btrfs_multi_bio **multi_ret, int mirror_num)
816 817 818 819 820
{
	struct extent_map *em;
	struct map_lookup *map;
	struct extent_map_tree *em_tree = &map_tree->map_tree;
	u64 offset;
821 822
	u64 stripe_offset;
	u64 stripe_nr;
823
	int stripes_allocated = 8;
824
	int stripe_index;
825 826
	int i;
	struct btrfs_multi_bio *multi = NULL;
827

828 829 830 831 832 833 834 835 836 837
	if (multi_ret && !(rw & (1 << BIO_RW))) {
		stripes_allocated = 1;
	}
again:
	if (multi_ret) {
		multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
				GFP_NOFS);
		if (!multi)
			return -ENOMEM;
	}
838 839 840 841 842 843 844 845

	spin_lock(&em_tree->lock);
	em = lookup_extent_mapping(em_tree, logical, *length);
	BUG_ON(!em);

	BUG_ON(em->start > logical || em->start + em->len < logical);
	map = (struct map_lookup *)em->bdev;
	offset = logical - em->start;
846

847 848 849
	if (mirror_num > map->num_stripes)
		mirror_num = 0;

850 851 852 853 854 855 856 857 858 859 860
	/* if our multi bio struct is too small, back off and try again */
	if (multi_ret && (rw & (1 << BIO_RW)) &&
	    stripes_allocated < map->num_stripes &&
	    ((map->type & BTRFS_BLOCK_GROUP_RAID1) ||
	     (map->type & BTRFS_BLOCK_GROUP_DUP))) {
		stripes_allocated = map->num_stripes;
		spin_unlock(&em_tree->lock);
		free_extent_map(em);
		kfree(multi);
		goto again;
	}
861 862 863 864 865 866 867 868 869 870 871 872 873
	stripe_nr = offset;
	/*
	 * stripe_nr counts the total number of stripes we have to stride
	 * to get to this block
	 */
	do_div(stripe_nr, map->stripe_len);

	stripe_offset = stripe_nr * map->stripe_len;
	BUG_ON(offset < stripe_offset);

	/* stripe_offset is the offset of this block in its stripe*/
	stripe_offset = offset - stripe_offset;

874 875 876 877 878 879 880 881 882 883 884 885 886
	if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
			 BTRFS_BLOCK_GROUP_DUP)) {
		/* we limit the length of each bio to what fits in a stripe */
		*length = min_t(u64, em->len - offset,
			      map->stripe_len - stripe_offset);
	} else {
		*length = em->len - offset;
	}
	if (!multi_ret)
		goto out;

	multi->num_stripes = 1;
	stripe_index = 0;
887 888
	if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
		if (rw & (1 << BIO_RW))
889
			multi->num_stripes = map->num_stripes;
890 891 892
		else if (mirror_num) {
			stripe_index = mirror_num - 1;
		} else {
893 894 895 896 897 898 899 900 901 902 903 904 905 906
			int i;
			u64 least = (u64)-1;
			struct btrfs_device *cur;

			for (i = 0; i < map->num_stripes; i++) {
				cur = map->stripes[i].dev;
				spin_lock(&cur->io_lock);
				if (cur->total_ios < least) {
					least = cur->total_ios;
					stripe_index = i;
				}
				spin_unlock(&cur->io_lock);
			}
		}
907
	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
908 909
		if (rw & (1 << BIO_RW))
			multi->num_stripes = map->num_stripes;
910 911
		else if (mirror_num)
			stripe_index = mirror_num - 1;
912 913 914 915 916 917 918 919
	} else {
		/*
		 * after this do_div call, stripe_nr is the number of stripes
		 * on this device we have to walk to find the data, and
		 * stripe_index is the number of our device in the stripe array
		 */
		stripe_index = do_div(stripe_nr, map->num_stripes);
	}
920
	BUG_ON(stripe_index >= map->num_stripes);
921 922 923 924 925 926 927 928
	BUG_ON(stripe_index != 0 && multi->num_stripes > 1);

	for (i = 0; i < multi->num_stripes; i++) {
		multi->stripes[i].physical =
			map->stripes[stripe_index].physical + stripe_offset +
			stripe_nr * map->stripe_len;
		multi->stripes[i].dev = map->stripes[stripe_index].dev;
		stripe_index++;
929
	}
930 931
	*multi_ret = multi;
out:
932 933 934 935 936
	free_extent_map(em);
	spin_unlock(&em_tree->lock);
	return 0;
}

937 938 939 940 941 942 943
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
static void end_bio_multi_stripe(struct bio *bio, int err)
#else
static int end_bio_multi_stripe(struct bio *bio,
				   unsigned int bytes_done, int err)
#endif
{
944
	struct btrfs_multi_bio *multi = bio->bi_private;
945 946 947 948 949 950 951 952

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
	if (bio->bi_size)
		return 1;
#endif
	if (err)
		multi->error = err;

953
	if (atomic_dec_and_test(&multi->stripes_pending)) {
954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969
		bio->bi_private = multi->private;
		bio->bi_end_io = multi->end_io;

		if (!err && multi->error)
			err = multi->error;
		kfree(multi);

		bio_endio(bio, err);
	} else {
		bio_put(bio);
	}
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
	return 0;
#endif
}

970 971
int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
		  int mirror_num)
972 973 974
{
	struct btrfs_mapping_tree *map_tree;
	struct btrfs_device *dev;
975
	struct bio *first_bio = bio;
976 977 978 979
	u64 logical = bio->bi_sector << 9;
	u64 length = 0;
	u64 map_length;
	struct bio_vec *bvec;
980
	struct btrfs_multi_bio *multi = NULL;
981 982
	int i;
	int ret;
983 984
	int dev_nr = 0;
	int total_devs = 1;
985 986 987 988

	bio_for_each_segment(bvec, bio, i) {
		length += bvec->bv_len;
	}
989

990 991
	map_tree = &root->fs_info->mapping_tree;
	map_length = length;
992

993 994
	ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
			      mirror_num);
995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006
	BUG_ON(ret);

	total_devs = multi->num_stripes;
	if (map_length < length) {
		printk("mapping failed logical %Lu bio len %Lu "
		       "len %Lu\n", logical, length, map_length);
		BUG();
	}
	multi->end_io = first_bio->bi_end_io;
	multi->private = first_bio->bi_private;
	atomic_set(&multi->stripes_pending, multi->num_stripes);

1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017
	while(dev_nr < total_devs) {
		if (total_devs > 1) {
			if (dev_nr < total_devs - 1) {
				bio = bio_clone(first_bio, GFP_NOFS);
				BUG_ON(!bio);
			} else {
				bio = first_bio;
			}
			bio->bi_private = multi;
			bio->bi_end_io = end_bio_multi_stripe;
		}
1018 1019
		bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
		dev = multi->stripes[dev_nr].dev;
1020 1021 1022 1023 1024 1025 1026
		bio->bi_bdev = dev->bdev;
		spin_lock(&dev->io_lock);
		dev->total_ios++;
		spin_unlock(&dev->io_lock);
		submit_bio(rw, bio);
		dev_nr++;
	}
1027 1028
	if (total_devs == 1)
		kfree(multi);
1029 1030 1031 1032 1033
	return 0;
}

struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid)
{
1034
	struct list_head *head = &root->fs_info->fs_devices->devices;
1035

1036
	return __find_device(head, devid);
1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048
}

static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
			  struct extent_buffer *leaf,
			  struct btrfs_chunk *chunk)
{
	struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
	struct map_lookup *map;
	struct extent_map *em;
	u64 logical;
	u64 length;
	u64 devid;
1049
	int num_stripes;
1050
	int ret;
1051
	int i;
1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074

	logical = key->objectid;
	length = key->offset;
	spin_lock(&map_tree->map_tree.lock);
	em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);

	/* already mapped? */
	if (em && em->start <= logical && em->start + em->len > logical) {
		free_extent_map(em);
		spin_unlock(&map_tree->map_tree.lock);
		return 0;
	} else if (em) {
		free_extent_map(em);
	}
	spin_unlock(&map_tree->map_tree.lock);

	map = kzalloc(sizeof(*map), GFP_NOFS);
	if (!map)
		return -ENOMEM;

	em = alloc_extent_map(GFP_NOFS);
	if (!em)
		return -ENOMEM;
1075 1076
	num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
	map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
1077 1078 1079 1080 1081 1082 1083 1084 1085 1086
	if (!map) {
		free_extent_map(em);
		return -ENOMEM;
	}

	em->bdev = (struct block_device *)map;
	em->start = logical;
	em->len = length;
	em->block_start = 0;

1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102
	map->num_stripes = num_stripes;
	map->io_width = btrfs_chunk_io_width(leaf, chunk);
	map->io_align = btrfs_chunk_io_align(leaf, chunk);
	map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
	map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
	map->type = btrfs_chunk_type(leaf, chunk);
	for (i = 0; i < num_stripes; i++) {
		map->stripes[i].physical =
			btrfs_stripe_offset_nr(leaf, chunk, i);
		devid = btrfs_stripe_devid_nr(leaf, chunk, i);
		map->stripes[i].dev = btrfs_find_device(root, devid);
		if (!map->stripes[i].dev) {
			kfree(map);
			free_extent_map(em);
			return -EIO;
		}
1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133
	}

	spin_lock(&map_tree->map_tree.lock);
	ret = add_extent_mapping(&map_tree->map_tree, em);
	BUG_ON(ret);
	spin_unlock(&map_tree->map_tree.lock);
	free_extent_map(em);

	return 0;
}

static int fill_device_from_item(struct extent_buffer *leaf,
				 struct btrfs_dev_item *dev_item,
				 struct btrfs_device *device)
{
	unsigned long ptr;

	device->devid = btrfs_device_id(leaf, dev_item);
	device->total_bytes = btrfs_device_total_bytes(leaf, dev_item);
	device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
	device->type = btrfs_device_type(leaf, dev_item);
	device->io_align = btrfs_device_io_align(leaf, dev_item);
	device->io_width = btrfs_device_io_width(leaf, dev_item);
	device->sector_size = btrfs_device_sector_size(leaf, dev_item);

	ptr = (unsigned long)btrfs_device_uuid(dev_item);
	read_extent_buffer(leaf, device->uuid, ptr, BTRFS_DEV_UUID_SIZE);

	return 0;
}

1134
static int read_one_dev(struct btrfs_root *root,
1135 1136 1137 1138 1139 1140 1141 1142
			struct extent_buffer *leaf,
			struct btrfs_dev_item *dev_item)
{
	struct btrfs_device *device;
	u64 devid;
	int ret;

	devid = btrfs_device_id(leaf, dev_item);
1143 1144
	device = btrfs_find_device(root, devid);
	if (!device) {
1145
		printk("warning devid %Lu not found already\n", devid);
1146 1147 1148
		device = kmalloc(sizeof(*device), GFP_NOFS);
		if (!device)
			return -ENOMEM;
1149 1150
		list_add(&device->dev_list,
			 &root->fs_info->fs_devices->devices);
1151 1152
		device->total_ios = 0;
		spin_lock_init(&device->io_lock);
1153
	}
1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166

	fill_device_from_item(leaf, dev_item, device);
	device->dev_root = root->fs_info->dev_root;
	ret = 0;
#if 0
	ret = btrfs_open_device(device);
	if (ret) {
		kfree(device);
	}
#endif
	return ret;
}

1167 1168 1169 1170 1171 1172 1173 1174 1175
int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
{
	struct btrfs_dev_item *dev_item;

	dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
						     dev_item);
	return read_one_dev(root, buf, dev_item);
}

1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
int btrfs_read_sys_array(struct btrfs_root *root)
{
	struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
	struct extent_buffer *sb = root->fs_info->sb_buffer;
	struct btrfs_disk_key *disk_key;
	struct btrfs_chunk *chunk;
	struct btrfs_key key;
	u32 num_stripes;
	u32 array_size;
	u32 len = 0;
	u8 *ptr;
	unsigned long sb_ptr;
	u32 cur;
	int ret;

	array_size = btrfs_super_sys_array_size(super_copy);

	/*
	 * we do this loop twice, once for the device items and
	 * once for all of the chunks.  This way there are device
	 * structs filled in for every chunk
	 */
	ptr = super_copy->sys_chunk_array;
	sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
	cur = 0;

	while (cur < array_size) {
		disk_key = (struct btrfs_disk_key *)ptr;
		btrfs_disk_key_to_cpu(&key, disk_key);

		len = sizeof(*disk_key);
		ptr += len;
		sb_ptr += len;
		cur += len;

1211
		if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1212
			chunk = (struct btrfs_chunk *)sb_ptr;
1213 1214
			ret = read_one_chunk(root, &key, sb, chunk);
			BUG_ON(ret);
1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269
			num_stripes = btrfs_chunk_num_stripes(sb, chunk);
			len = btrfs_chunk_item_size(num_stripes);
		} else {
			BUG();
		}
		ptr += len;
		sb_ptr += len;
		cur += len;
	}
	return 0;
}

int btrfs_read_chunk_tree(struct btrfs_root *root)
{
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	struct btrfs_key key;
	struct btrfs_key found_key;
	int ret;
	int slot;

	root = root->fs_info->chunk_root;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	/* first we search for all of the device items, and then we
	 * read in all of the chunk items.  This way we can create chunk
	 * mappings that reference all of the devices that are afound
	 */
	key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
	key.offset = 0;
	key.type = 0;
again:
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	while(1) {
		leaf = path->nodes[0];
		slot = path->slots[0];
		if (slot >= btrfs_header_nritems(leaf)) {
			ret = btrfs_next_leaf(root, path);
			if (ret == 0)
				continue;
			if (ret < 0)
				goto error;
			break;
		}
		btrfs_item_key_to_cpu(leaf, &found_key, slot);
		if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
			if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
				break;
			if (found_key.type == BTRFS_DEV_ITEM_KEY) {
				struct btrfs_dev_item *dev_item;
				dev_item = btrfs_item_ptr(leaf, slot,
						  struct btrfs_dev_item);
1270
				ret = read_one_dev(root, leaf, dev_item);
1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291
				BUG_ON(ret);
			}
		} else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
			struct btrfs_chunk *chunk;
			chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
			ret = read_one_chunk(root, &found_key, leaf, chunk);
		}
		path->slots[0]++;
	}
	if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
		key.objectid = 0;
		btrfs_release_path(root, path);
		goto again;
	}

	btrfs_free_path(path);
	ret = 0;
error:
	return ret;
}