linux/fs/btrfs/volumes.c

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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>
#include "ctree.h"
#include "extent_map.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#include "volumes.h"
struct map_lookup {
struct btrfs_device *dev;
u64 physical;
};
/*
* 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 */
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);
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_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->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 avail;
u64 max_avail = 0;
int num_stripes = 1;
int looped = 0;
int ret;
int index;
struct btrfs_key key;
if (list_empty(dev_list))
return -ENOSPC;
again:
INIT_LIST_HEAD(&private_devs);
cur = dev_list->next;
index = 0;
/* 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 >= calc_size) {
list_move_tail(&device->dev_list, &private_devs);
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;
stripes = &chunk->stripe;
*num_bytes = calc_size;
index = 0;
while(index < num_stripes) {
BUG_ON(list_empty(&private_devs));
cur = private_devs.next;
device = list_entry(cur, struct btrfs_device, dev_list);
list_move_tail(&device->dev_list, dev_list);
ret = btrfs_alloc_dev_extent(trans, device,
key.objectid,
calc_size, &dev_offset);
BUG_ON(ret);
device->bytes_used += calc_size;
ret = btrfs_update_device(trans, device);
BUG_ON(ret);
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, 64 * 1024);
btrfs_set_stack_chunk_type(chunk, type);
btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
btrfs_set_stack_chunk_io_align(chunk, extent_root->sectorsize);
btrfs_set_stack_chunk_io_width(chunk, extent_root->sectorsize);
btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
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;
map = kmalloc(sizeof(*map), GFP_NOFS);
if (!map) {
free_extent_map(em);
return -ENOMEM;
}
em->bdev = (struct block_device *)map;
em->start = key.objectid;
em->len = key.offset;
em->block_start = 0;
map->physical = physical;
map->dev = device;
if (!map->dev) {
kfree(map);
free_extent_map(em);
return -EIO;
}
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,
u64 logical, u64 *phys, u64 *length,
struct btrfs_device **dev)
{
struct extent_map *em;
struct map_lookup *map;
struct extent_map_tree *em_tree = &map_tree->map_tree;
u64 offset;
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;
*phys = map->physical + offset;
*length = em->len - offset;
*dev = map->dev;
free_extent_map(em);
spin_unlock(&em_tree->lock);
return 0;
}
int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio)
{
struct btrfs_mapping_tree *map_tree;
struct btrfs_device *dev;
u64 logical = bio->bi_sector << 9;
u64 physical;
u64 length = 0;
u64 map_length;
struct bio_vec *bvec;
int i;
int ret;
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, logical, &physical, &map_length, &dev);
if (map_length < length) {
printk("mapping failed logical %Lu bio len %Lu physical %Lu "
"len %Lu\n", logical, length, physical, map_length);
BUG();
}
BUG_ON(map_length < length);
bio->bi_sector = physical >> 9;
bio->bi_bdev = dev->bdev;
submit_bio(rw, bio);
return 0;
}
struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid)
{
struct btrfs_device *dev;
struct list_head *cur = root->fs_info->devices.next;
struct list_head *head = &root->fs_info->devices;
while(cur != head) {
dev = list_entry(cur, struct btrfs_device, dev_list);
if (dev->devid == devid)
return dev;
cur = cur->next;
}
return NULL;
}
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 ret;
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;
map = kmalloc(sizeof(*map), 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->physical = btrfs_stripe_offset_nr(leaf, chunk, 0);
devid = btrfs_stripe_devid_nr(leaf, chunk, 0);
map->dev = btrfs_find_device(root, devid);
if (!map->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) {
device = kmalloc(sizeof(*device), GFP_NOFS);
if (!device)
return -ENOMEM;
list_add(&device->dev_list, &root->fs_info->devices);
}
fill_device_from_item(leaf, dev_item, device);
device->dev_root = root->fs_info->dev_root;
device->bdev = root->fs_info->sb->s_bdev;
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;
}