kernel-fxtec-pro1x/fs/btrfs/volumes.c
Chris Mason cea9e4452e Change btrfs_map_block to return a structure with mappings for all stripes
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-25 11:04:01 -04:00

1260 lines
32 KiB
C

/*
* 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>
#include <linux/buffer_head.h>
#include <asm/div64.h>
#include "ctree.h"
#include "extent_map.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#include "volumes.h"
struct map_lookup {
u64 type;
int io_align;
int io_width;
int stripe_len;
int sector_size;
int num_stripes;
struct btrfs_bio_stripe stripes[];
};
#define map_lookup_size(n) (sizeof(struct map_lookup) + \
(sizeof(struct btrfs_bio_stripe) * (n)))
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);
ret = -EINVAL;
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;
}
/*
* 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 */
/* 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);
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);
if (*start + num_bytes > search_end) {
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);
if (ret) {
goto err;
}
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,
sizeof(*dev_item));
if (ret)
goto out;
leaf = path->nodes[0];
dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
device->devid = free_devid;
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,
u64 *num_bytes, u64 type)
{
u64 dev_offset;
struct btrfs_fs_info *info = extent_root->fs_info;
struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
struct btrfs_stripe *stripes;
struct btrfs_device *device = NULL;
struct btrfs_chunk *chunk;
struct list_head private_devs;
struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices;
struct list_head *cur;
struct extent_map_tree *em_tree;
struct map_lookup *map;
struct extent_map *em;
u64 physical;
u64 calc_size = 1024 * 1024 * 1024;
u64 min_free = calc_size;
u64 avail;
u64 max_avail = 0;
int num_stripes = 1;
int looped = 0;
int ret;
int index;
int stripe_len = 64 * 1024;
struct btrfs_key key;
if (list_empty(dev_list))
return -ENOSPC;
if (type & (BTRFS_BLOCK_GROUP_RAID0))
num_stripes = btrfs_super_num_devices(&info->super_copy);
if (type & (BTRFS_BLOCK_GROUP_DUP))
num_stripes = 2;
if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
num_stripes = min_t(u64, 2,
btrfs_super_num_devices(&info->super_copy));
}
again:
INIT_LIST_HEAD(&private_devs);
cur = dev_list->next;
index = 0;
if (type & BTRFS_BLOCK_GROUP_DUP)
min_free = calc_size * 2;
/* build a private list of devices we will allocate from */
while(index < num_stripes) {
device = list_entry(cur, struct btrfs_device, dev_list);
avail = device->total_bytes - device->bytes_used;
cur = cur->next;
if (avail > max_avail)
max_avail = avail;
if (avail >= min_free) {
list_move_tail(&device->dev_list, &private_devs);
index++;
if (type & BTRFS_BLOCK_GROUP_DUP)
index++;
}
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;
}
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;
map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
if (!map) {
kfree(chunk);
return -ENOMEM;
}
stripes = &chunk->stripe;
if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
*num_bytes = calc_size;
else
*num_bytes = calc_size * num_stripes;
index = 0;
printk("new chunk type %Lu start %Lu size %Lu\n", type, key.objectid, *num_bytes);
while(index < num_stripes) {
BUG_ON(list_empty(&private_devs));
cur = private_devs.next;
device = list_entry(cur, struct btrfs_device, dev_list);
/* 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);
ret = btrfs_alloc_dev_extent(trans, device,
key.objectid,
calc_size, &dev_offset);
BUG_ON(ret);
printk("alloc chunk start %Lu size %Lu from dev %Lu type %Lu\n", key.objectid, calc_size, device->devid, type);
device->bytes_used += calc_size;
ret = btrfs_update_device(trans, device);
BUG_ON(ret);
map->stripes[index].dev = device;
map->stripes[index].physical = dev_offset;
btrfs_set_stack_stripe_devid(stripes + index, device->devid);
btrfs_set_stack_stripe_offset(stripes + index, dev_offset);
physical = dev_offset;
index++;
}
BUG_ON(!list_empty(&private_devs));
/* 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);
btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
btrfs_set_stack_chunk_type(chunk, type);
btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
btrfs_set_stack_chunk_io_align(chunk, stripe_len);
btrfs_set_stack_chunk_io_width(chunk, stripe_len);
btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
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;
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);
}
}
int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
u64 logical, u64 *length,
struct btrfs_multi_bio **multi_ret)
{
struct extent_map *em;
struct map_lookup *map;
struct extent_map_tree *em_tree = &map_tree->map_tree;
u64 offset;
u64 stripe_offset;
u64 stripe_nr;
int stripes_allocated = 8;
int stripe_index;
int i;
struct btrfs_multi_bio *multi = NULL;
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;
}
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;
/* 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;
}
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;
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;
if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
if (rw & (1 << BIO_RW))
multi->num_stripes = map->num_stripes;
else {
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);
}
}
} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
if (rw & (1 << BIO_RW))
multi->num_stripes = map->num_stripes;
} 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);
}
BUG_ON(stripe_index >= map->num_stripes);
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++;
}
*multi_ret = multi;
out:
free_extent_map(em);
spin_unlock(&em_tree->lock);
return 0;
}
#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
{
struct btrfs_multi_bio *multi = bio->bi_private;
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
if (bio->bi_size)
return 1;
#endif
if (err)
multi->error = err;
if (atomic_dec_and_test(&multi->stripes_pending)) {
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
}
int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio)
{
struct btrfs_mapping_tree *map_tree;
struct btrfs_device *dev;
struct bio *first_bio = bio;
u64 logical = bio->bi_sector << 9;
u64 length = 0;
u64 map_length;
struct bio_vec *bvec;
struct btrfs_multi_bio *multi = NULL;
int i;
int ret;
int dev_nr = 0;
int total_devs = 1;
bio_for_each_segment(bvec, bio, i) {
length += bvec->bv_len;
}
map_tree = &root->fs_info->mapping_tree;
map_length = length;
ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi);
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);
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;
}
bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
dev = multi->stripes[dev_nr].dev;
bio->bi_bdev = dev->bdev;
spin_lock(&dev->io_lock);
dev->total_ios++;
spin_unlock(&dev->io_lock);
submit_bio(rw, bio);
dev_nr++;
}
if (total_devs == 1)
kfree(multi);
return 0;
}
struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid)
{
struct list_head *head = &root->fs_info->fs_devices->devices;
return __find_device(head, devid);
}
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;
int num_stripes;
int ret;
int i;
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;
num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
if (!map) {
free_extent_map(em);
return -ENOMEM;
}
em->bdev = (struct block_device *)map;
em->start = logical;
em->len = length;
em->block_start = 0;
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;
}
}
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;
}
static int read_one_dev(struct btrfs_root *root,
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);
device = btrfs_find_device(root, devid);
if (!device) {
printk("warning devid %Lu not found already\n", devid);
device = kmalloc(sizeof(*device), GFP_NOFS);
if (!device)
return -ENOMEM;
list_add(&device->dev_list,
&root->fs_info->fs_devices->devices);
device->total_ios = 0;
spin_lock_init(&device->io_lock);
}
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;
}
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);
}
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;
if (key.type == BTRFS_CHUNK_ITEM_KEY) {
chunk = (struct btrfs_chunk *)sb_ptr;
ret = read_one_chunk(root, &key, sb, chunk);
BUG_ON(ret);
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);
ret = read_one_dev(root, leaf, dev_item);
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;
}