linux/fs/btrfs/extent-tree.c

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#include <linux/module.h>
#include "ctree.h"
#include "disk-io.h"
#include "print-tree.h"
#include "transaction.h"
static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*orig_root, u64 num_blocks, u64 search_start, u64
search_end, struct btrfs_key *ins);
static int finish_current_insert(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root);
static int del_pending_extents(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root);
struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
struct btrfs_block_group_cache
*hint, int data)
{
struct btrfs_block_group_cache *cache[8];
struct btrfs_block_group_cache *found_group = NULL;
struct btrfs_fs_info *info = root->fs_info;
u64 used;
u64 last = 0;
u64 hint_last;
int i;
int ret;
int full_search = 0;
if (hint) {
used = btrfs_block_group_used(&hint->item);
if (used < (hint->key.offset * 2) / 3) {
return hint;
}
radix_tree_tag_clear(&info->block_group_radix,
hint->key.objectid + hint->key.offset - 1,
BTRFS_BLOCK_GROUP_AVAIL);
last = hint->key.objectid + hint->key.offset;
hint_last = last;
} else {
hint_last = 0;
last = 0;
}
while(1) {
ret = radix_tree_gang_lookup_tag(&info->block_group_radix,
(void **)cache,
last, ARRAY_SIZE(cache),
BTRFS_BLOCK_GROUP_AVAIL);
if (!ret)
break;
for (i = 0; i < ret; i++) {
used = btrfs_block_group_used(&cache[i]->item);
if (used < (cache[i]->key.offset * 2) / 3) {
info->block_group_cache = cache[i];
found_group = cache[i];
goto found;
}
radix_tree_tag_clear(&info->block_group_radix,
cache[i]->key.objectid +
cache[i]->key.offset - 1,
BTRFS_BLOCK_GROUP_AVAIL);
last = cache[i]->key.objectid +
cache[i]->key.offset;
}
}
last = hint_last;
again:
while(1) {
ret = radix_tree_gang_lookup(&info->block_group_radix,
(void **)cache,
last, ARRAY_SIZE(cache));
if (!ret)
break;
for (i = 0; i < ret; i++) {
used = btrfs_block_group_used(&cache[i]->item);
if (used < cache[i]->key.offset) {
info->block_group_cache = cache[i];
found_group = cache[i];
goto found;
}
radix_tree_tag_clear(&info->block_group_radix,
cache[i]->key.objectid +
cache[i]->key.offset - 1,
BTRFS_BLOCK_GROUP_AVAIL);
last = cache[i]->key.objectid +
cache[i]->key.offset;
}
}
info->block_group_cache = NULL;
if (!full_search) {
last = 0;
full_search = 1;
goto again;
}
found:
if (!found_group) {
ret = radix_tree_gang_lookup(&info->block_group_radix,
(void **)&found_group, 0, 1);
BUG_ON(ret != 1);
}
return found_group;
}
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 blocknr, u64 num_blocks)
{
struct btrfs_path *path;
int ret;
struct btrfs_key key;
struct btrfs_leaf *l;
struct btrfs_extent_item *item;
struct btrfs_key ins;
u32 refs;
find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1,
&ins);
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
key.objectid = blocknr;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
key.offset = num_blocks;
ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
0, 1);
if (ret != 0) {
printk("can't find block %Lu %Lu\n", blocknr, num_blocks);
BUG();
}
BUG_ON(ret != 0);
l = btrfs_buffer_leaf(path->nodes[0]);
item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(item);
btrfs_set_extent_refs(item, refs + 1);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(root->fs_info->extent_root, path);
btrfs_free_path(path);
finish_current_insert(trans, root->fs_info->extent_root);
del_pending_extents(trans, root->fs_info->extent_root);
return 0;
}
static int lookup_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 blocknr,
u64 num_blocks, u32 *refs)
{
struct btrfs_path *path;
int ret;
struct btrfs_key key;
struct btrfs_leaf *l;
struct btrfs_extent_item *item;
path = btrfs_alloc_path();
btrfs_init_path(path);
key.objectid = blocknr;
key.offset = num_blocks;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
0, 0);
if (ret != 0)
BUG();
l = btrfs_buffer_leaf(path->nodes[0]);
item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
*refs = btrfs_extent_refs(item);
btrfs_release_path(root->fs_info->extent_root, path);
btrfs_free_path(path);
return 0;
}
int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
return btrfs_inc_extent_ref(trans, root, bh_blocknr(root->node), 1);
}
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct buffer_head *buf)
{
u64 blocknr;
struct btrfs_node *buf_node;
struct btrfs_leaf *buf_leaf;
struct btrfs_disk_key *key;
struct btrfs_file_extent_item *fi;
int i;
int leaf;
int ret;
if (!root->ref_cows)
return 0;
buf_node = btrfs_buffer_node(buf);
leaf = btrfs_is_leaf(buf_node);
buf_leaf = btrfs_buffer_leaf(buf);
for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
if (leaf) {
key = &buf_leaf->items[i].key;
if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(buf_leaf, i,
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
ret = btrfs_inc_extent_ref(trans, root,
btrfs_file_extent_disk_blocknr(fi),
btrfs_file_extent_disk_num_blocks(fi));
BUG_ON(ret);
} else {
blocknr = btrfs_node_blockptr(buf_node, i);
ret = btrfs_inc_extent_ref(trans, root, blocknr, 1);
BUG_ON(ret);
}
}
return 0;
}
static int write_one_cache_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_block_group_cache *cache)
{
int ret;
int pending_ret;
struct btrfs_root *extent_root = root->fs_info->extent_root;
struct btrfs_block_group_item *bi;
struct btrfs_key ins;
find_free_extent(trans, extent_root, 0, 0, (u64)-1, &ins);
ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
BUG_ON(ret);
bi = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_block_group_item);
memcpy(bi, &cache->item, sizeof(*bi));
mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(extent_root, path);
finish_current_insert(trans, extent_root);
pending_ret = del_pending_extents(trans, extent_root);
if (ret)
return ret;
if (pending_ret)
return pending_ret;
return 0;
}
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_block_group_cache *cache[8];
int ret;
int err = 0;
int werr = 0;
struct radix_tree_root *radix = &root->fs_info->block_group_radix;
int i;
struct btrfs_path *path;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while(1) {
ret = radix_tree_gang_lookup_tag(radix, (void **)cache,
0, ARRAY_SIZE(cache),
BTRFS_BLOCK_GROUP_DIRTY);
if (!ret)
break;
for (i = 0; i < ret; i++) {
radix_tree_tag_clear(radix, cache[i]->key.objectid +
cache[i]->key.offset - 1,
BTRFS_BLOCK_GROUP_DIRTY);
err = write_one_cache_group(trans, root,
path, cache[i]);
if (err)
werr = err;
cache[i]->last_alloc = cache[i]->first_free;
}
}
btrfs_free_path(path);
return werr;
}
static int update_block_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 blocknr, u64 num, int alloc)
{
struct btrfs_block_group_cache *cache;
struct btrfs_fs_info *info = root->fs_info;
u64 total = num;
u64 old_val;
u64 block_in_group;
int ret;
while(total) {
ret = radix_tree_gang_lookup(&info->block_group_radix,
(void **)&cache, blocknr, 1);
if (!ret) {
printk(KERN_CRIT "blocknr %Lu lookup failed\n",
blocknr);
return -1;
}
block_in_group = blocknr - cache->key.objectid;
WARN_ON(block_in_group > cache->key.offset);
radix_tree_tag_set(&info->block_group_radix,
cache->key.objectid + cache->key.offset - 1,
BTRFS_BLOCK_GROUP_DIRTY);
old_val = btrfs_block_group_used(&cache->item);
num = min(total, cache->key.offset - block_in_group);
total -= num;
blocknr += num;
if (alloc) {
old_val += num;
if (blocknr > cache->last_alloc)
cache->last_alloc = blocknr;
} else {
old_val -= num;
if (blocknr < cache->first_free)
cache->first_free = blocknr;
}
btrfs_set_block_group_used(&cache->item, old_val);
}
return 0;
}
static int try_remove_page(struct address_space *mapping, unsigned long index)
{
int ret;
ret = invalidate_mapping_pages(mapping, index, index);
return ret;
}
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
btrfs_root *root)
{
unsigned long gang[8];
struct inode *btree_inode = root->fs_info->btree_inode;
u64 first = 0;
int ret;
int i;
struct radix_tree_root *pinned_radix = &root->fs_info->pinned_radix;
while(1) {
ret = find_first_radix_bit(pinned_radix, gang,
ARRAY_SIZE(gang));
if (!ret)
break;
if (!first)
first = gang[0];
for (i = 0; i < ret; i++) {
clear_radix_bit(pinned_radix, gang[i]);
try_remove_page(btree_inode->i_mapping,
gang[i] << (PAGE_CACHE_SHIFT -
btree_inode->i_blkbits));
}
}
return 0;
}
static int finish_current_insert(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root)
{
struct btrfs_key ins;
struct btrfs_extent_item extent_item;
int i;
int ret;
u64 super_blocks_used;
struct btrfs_fs_info *info = extent_root->fs_info;
btrfs_set_extent_refs(&extent_item, 1);
ins.offset = 1;
ins.flags = 0;
btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
btrfs_set_extent_owner(&extent_item, extent_root->root_key.objectid);
for (i = 0; i < extent_root->fs_info->extent_tree_insert_nr; i++) {
ins.objectid = extent_root->fs_info->extent_tree_insert[i];
super_blocks_used = btrfs_super_blocks_used(info->disk_super);
btrfs_set_super_blocks_used(info->disk_super,
super_blocks_used + 1);
ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
sizeof(extent_item));
BUG_ON(ret);
}
extent_root->fs_info->extent_tree_insert_nr = 0;
extent_root->fs_info->extent_tree_prealloc_nr = 0;
return 0;
}
static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
{
int err;
struct btrfs_header *header;
struct buffer_head *bh;
if (!pending) {
bh = btrfs_find_tree_block(root, blocknr);
if (bh) {
if (buffer_uptodate(bh)) {
u64 transid =
root->fs_info->running_transaction->transid;
header = btrfs_buffer_header(bh);
if (btrfs_header_generation(header) ==
transid) {
btrfs_block_release(root, bh);
return 0;
}
}
btrfs_block_release(root, bh);
}
err = set_radix_bit(&root->fs_info->pinned_radix, blocknr);
} else {
err = set_radix_bit(&root->fs_info->pending_del_radix, blocknr);
}
BUG_ON(err);
return 0;
}
/*
* remove an extent from the root, returns 0 on success
*/
static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 blocknr, u64 num_blocks, int pin)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_root *extent_root = info->extent_root;
int ret;
struct btrfs_extent_item *ei;
struct btrfs_key ins;
u32 refs;
key.objectid = blocknr;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
key.offset = num_blocks;
find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
if (ret) {
printk("failed to find %Lu\n", key.objectid);
btrfs_print_tree(extent_root, extent_root->node);
printk("failed to find %Lu\n", key.objectid);
BUG();
}
ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_extent_item);
BUG_ON(ei->refs == 0);
refs = btrfs_extent_refs(ei) - 1;
btrfs_set_extent_refs(ei, refs);
btrfs_mark_buffer_dirty(path->nodes[0]);
if (refs == 0) {
u64 super_blocks_used;
if (pin) {
ret = pin_down_block(root, blocknr, 0);
BUG_ON(ret);
}
super_blocks_used = btrfs_super_blocks_used(info->disk_super);
btrfs_set_super_blocks_used(info->disk_super,
super_blocks_used - num_blocks);
ret = btrfs_del_item(trans, extent_root, path);
if (ret)
BUG();
ret = update_block_group(trans, root, blocknr, num_blocks, 0);
BUG_ON(ret);
}
btrfs_release_path(extent_root, path);
btrfs_free_path(path);
finish_current_insert(trans, extent_root);
return ret;
}
/*
* find all the blocks marked as pending in the radix tree and remove
* them from the extent map
*/
static int del_pending_extents(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root)
{
int ret;
int wret;
int err = 0;
unsigned long gang[4];
int i;
struct radix_tree_root *pending_radix;
struct radix_tree_root *pinned_radix;
pending_radix = &extent_root->fs_info->pending_del_radix;
pinned_radix = &extent_root->fs_info->pinned_radix;
while(1) {
ret = find_first_radix_bit(pending_radix, gang,
ARRAY_SIZE(gang));
if (!ret)
break;
for (i = 0; i < ret; i++) {
wret = set_radix_bit(pinned_radix, gang[i]);
BUG_ON(wret);
wret = clear_radix_bit(pending_radix, gang[i]);
BUG_ON(wret);
wret = __free_extent(trans, extent_root,
gang[i], 1, 0);
if (wret)
err = wret;
}
}
return err;
}
/*
* remove an extent from the root, returns 0 on success
*/
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 blocknr, u64 num_blocks, int pin)
{
struct btrfs_root *extent_root = root->fs_info->extent_root;
int pending_ret;
int ret;
if (root == extent_root) {
pin_down_block(root, blocknr, 1);
return 0;
}
ret = __free_extent(trans, root, blocknr, num_blocks, pin);
pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
return ret ? ret : pending_ret;
}
/*
* walks the btree of allocated extents and find a hole of a given size.
* The key ins is changed to record the hole:
* ins->objectid == block start
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == number of blocks
* Any available blocks before search_start are skipped.
*/
static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*orig_root, u64 num_blocks, u64 search_start, u64
search_end, struct btrfs_key *ins)
{
struct btrfs_path *path;
struct btrfs_key key;
int ret;
u64 hole_size = 0;
int slot = 0;
u64 last_block = 0;
u64 test_block;
int start_found;
struct btrfs_leaf *l;
struct btrfs_root * root = orig_root->fs_info->extent_root;
struct btrfs_fs_info *info = root->fs_info;
int total_needed = num_blocks;
int total_found = 0;
int fill_prealloc = 0;
int level;
int update_block_group = 0;
struct btrfs_block_group_cache *hint_block_group;
path = btrfs_alloc_path();
ins->flags = 0;
btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
level = btrfs_header_level(btrfs_buffer_header(root->node));
/* find search start here */
if (0 && search_start && num_blocks) {
u64 used;
ret = radix_tree_gang_lookup(&info->block_group_radix,
(void **)&hint_block_group,
search_start, 1);
if (ret) {
used = btrfs_block_group_used(&hint_block_group->item);
if (used > (hint_block_group->key.offset * 9) / 10)
search_start = 0;
else if (search_start < hint_block_group->last_alloc)
search_start = hint_block_group->last_alloc;
} else {
search_start = 0;
}
}
if (num_blocks == 0) {
fill_prealloc = 1;
num_blocks = 1;
total_needed = (min(level + 1, BTRFS_MAX_LEVEL) + 2) * 3;
}
if (1 || !search_start) {
trans->block_group = btrfs_find_block_group(root,
trans->block_group,
0);
if (trans->block_group->last_alloc > search_start)
search_start = trans->block_group->last_alloc;
update_block_group = 1;
}
check_failed:
btrfs_init_path(path);
ins->objectid = search_start;
ins->offset = 0;
start_found = 0;
ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
if (ret < 0)
goto error;
if (path->slots[0] > 0)
path->slots[0]--;
while (1) {
l = btrfs_buffer_leaf(path->nodes[0]);
slot = path->slots[0];
if (slot >= btrfs_header_nritems(&l->header)) {
if (fill_prealloc) {
info->extent_tree_prealloc_nr = 0;
total_found = 0;
}
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto error;
if (!start_found) {
ins->objectid = search_start;
ins->offset = (u64)-1 - search_start;
start_found = 1;
goto check_pending;
}
ins->objectid = last_block > search_start ?
last_block : search_start;
ins->offset = (u64)-1 - ins->objectid;
goto check_pending;
}
btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
goto next;
if (key.objectid >= search_start) {
if (start_found) {
if (last_block < search_start)
last_block = search_start;
hole_size = key.objectid - last_block;
if (hole_size >= num_blocks) {
ins->objectid = last_block;
ins->offset = hole_size;
goto check_pending;
}
}
}
start_found = 1;
last_block = key.objectid + key.offset;
next:
path->slots[0]++;
}
// FIXME -ENOSPC
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(ins->objectid < search_start);
if (ins->objectid >= btrfs_super_total_blocks(info->disk_super)) {
if (search_start == 0)
return -ENOSPC;
search_start = 0;
goto check_failed;
}
for (test_block = ins->objectid;
test_block < ins->objectid + num_blocks; test_block++) {
if (test_radix_bit(&info->pinned_radix, test_block)) {
search_start = test_block + 1;
goto check_failed;
}
}
if (!fill_prealloc && info->extent_tree_insert_nr) {
u64 last =
info->extent_tree_insert[info->extent_tree_insert_nr - 1];
if (ins->objectid + num_blocks >
info->extent_tree_insert[0] &&
ins->objectid <= last) {
search_start = last + 1;
WARN_ON(1);
goto check_failed;
}
}
if (!fill_prealloc && info->extent_tree_prealloc_nr) {
u64 first =
info->extent_tree_prealloc[info->extent_tree_prealloc_nr - 1];
if (ins->objectid + num_blocks > first &&
ins->objectid <= info->extent_tree_prealloc[0]) {
search_start = info->extent_tree_prealloc[0] + 1;
WARN_ON(1);
goto check_failed;
}
}
if (fill_prealloc) {
int nr;
test_block = ins->objectid;
while(test_block < ins->objectid + ins->offset &&
total_found < total_needed) {
nr = total_needed - total_found - 1;
BUG_ON(nr < 0);
info->extent_tree_prealloc[nr] = test_block;
total_found++;
test_block++;
}
if (total_found < total_needed) {
search_start = test_block;
goto check_failed;
}
info->extent_tree_prealloc_nr = total_found;
}
if (update_block_group) {
ret = radix_tree_gang_lookup(&info->block_group_radix,
(void **)&trans->block_group,
ins->objectid, 1);
if (ret) {
trans->block_group->last_alloc = ins->objectid;
}
}
ins->offset = num_blocks;
btrfs_free_path(path);
return 0;
error:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
}
/*
* finds a free extent and does all the dirty work required for allocation
* returns the key for the extent through ins, and a tree buffer for
* the first block of the extent through buf.
*
* returns 0 if everything worked, non-zero otherwise.
*/
int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 owner,
u64 num_blocks, u64 search_start,
u64 search_end, struct btrfs_key *ins)
{
int ret;
int pending_ret;
u64 super_blocks_used;
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_root *extent_root = info->extent_root;
struct btrfs_extent_item extent_item;
struct btrfs_key prealloc_key;
btrfs_set_extent_refs(&extent_item, 1);
btrfs_set_extent_owner(&extent_item, owner);
if (root == extent_root) {
int nr;
BUG_ON(info->extent_tree_prealloc_nr == 0);
BUG_ON(num_blocks != 1);
ins->offset = 1;
info->extent_tree_prealloc_nr--;
nr = info->extent_tree_prealloc_nr;
ins->objectid = info->extent_tree_prealloc[nr];
info->extent_tree_insert[info->extent_tree_insert_nr++] =
ins->objectid;
ret = update_block_group(trans, root,
ins->objectid, ins->offset, 1);
BUG_ON(ret);
return 0;
}
/* do the real allocation */
ret = find_free_extent(trans, root, num_blocks, search_start,
search_end, ins);
if (ret)
return ret;
/* then do prealloc for the extent tree */
ret = find_free_extent(trans, root, 0, ins->objectid + ins->offset,
search_end, &prealloc_key);
if (ret)
return ret;
super_blocks_used = btrfs_super_blocks_used(info->disk_super);
btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
num_blocks);
ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
sizeof(extent_item));
finish_current_insert(trans, extent_root);
pending_ret = del_pending_extents(trans, extent_root);
if (ret)
return ret;
if (pending_ret)
return pending_ret;
ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
return 0;
}
/*
* helper function to allocate a block for a given tree
* returns the tree buffer or NULL.
*/
struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 hint)
{
struct btrfs_key ins;
int ret;
struct buffer_head *buf;
ret = btrfs_alloc_extent(trans, root, root->root_key.objectid,
1, hint, (unsigned long)-1, &ins);
if (ret) {
BUG();
return NULL;
}
BUG_ON(ret);
buf = btrfs_find_create_tree_block(root, ins.objectid);
set_buffer_uptodate(buf);
set_radix_bit(&trans->transaction->dirty_pages, buf->b_page->index);
return buf;
}
static int drop_leaf_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct buffer_head *cur)
{
struct btrfs_disk_key *key;
struct btrfs_leaf *leaf;
struct btrfs_file_extent_item *fi;
int i;
int nritems;
int ret;
BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
leaf = btrfs_buffer_leaf(cur);
nritems = btrfs_header_nritems(&leaf->header);
for (i = 0; i < nritems; i++) {
key = &leaf->items[i].key;
if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(fi) == BTRFS_FILE_EXTENT_INLINE)
continue;
/*
* FIXME make sure to insert a trans record that
* repeats the snapshot del on crash
*/
ret = btrfs_free_extent(trans, root,
btrfs_file_extent_disk_blocknr(fi),
btrfs_file_extent_disk_num_blocks(fi),
0);
BUG_ON(ret);
}
return 0;
}
/*
* helper function for drop_snapshot, this walks down the tree dropping ref
* counts as it goes.
*/
static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int *level)
{
struct buffer_head *next;
struct buffer_head *cur;
u64 blocknr;
int ret;
u32 refs;
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
ret = lookup_extent_ref(trans, root, bh_blocknr(path->nodes[*level]),
1, &refs);
BUG_ON(ret);
if (refs > 1)
goto out;
/*
* walk down to the last node level and free all the leaves
*/
while(*level >= 0) {
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
cur = path->nodes[*level];
if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
WARN_ON(1);
if (path->slots[*level] >=
btrfs_header_nritems(btrfs_buffer_header(cur)))
break;
if (*level == 0) {
ret = drop_leaf_ref(trans, root, cur);
BUG_ON(ret);
break;
}
blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
path->slots[*level]);
ret = lookup_extent_ref(trans, root, blocknr, 1, &refs);
BUG_ON(ret);
if (refs != 1) {
path->slots[*level]++;
ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
BUG_ON(ret);
continue;
}
next = read_tree_block(root, blocknr);
WARN_ON(*level <= 0);
if (path->nodes[*level-1])
btrfs_block_release(root, path->nodes[*level-1]);
path->nodes[*level-1] = next;
*level = btrfs_header_level(btrfs_buffer_header(next));
path->slots[*level] = 0;
}
out:
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
ret = btrfs_free_extent(trans, root,
bh_blocknr(path->nodes[*level]), 1, 1);
btrfs_block_release(root, path->nodes[*level]);
path->nodes[*level] = NULL;
*level += 1;
BUG_ON(ret);
return 0;
}
/*
* helper for dropping snapshots. This walks back up the tree in the path
* to find the first node higher up where we haven't yet gone through
* all the slots
*/
static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int *level)
{
int i;
int slot;
int ret;
for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
slot = path->slots[i];
if (slot < btrfs_header_nritems(
btrfs_buffer_header(path->nodes[i])) - 1) {
path->slots[i]++;
*level = i;
return 0;
} else {
ret = btrfs_free_extent(trans, root,
bh_blocknr(path->nodes[*level]),
1, 1);
BUG_ON(ret);
btrfs_block_release(root, path->nodes[*level]);
path->nodes[*level] = NULL;
*level = i + 1;
}
}
return 1;
}
/*
* drop the reference count on the tree rooted at 'snap'. This traverses
* the tree freeing any blocks that have a ref count of zero after being
* decremented.
*/
int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct buffer_head *snap)
{
int ret = 0;
int wret;
int level;
struct btrfs_path *path;
int i;
int orig_level;
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
level = btrfs_header_level(btrfs_buffer_header(snap));
orig_level = level;
path->nodes[level] = snap;
path->slots[level] = 0;
while(1) {
wret = walk_down_tree(trans, root, path, &level);
if (wret > 0)
break;
if (wret < 0)
ret = wret;
wret = walk_up_tree(trans, root, path, &level);
if (wret > 0)
break;
if (wret < 0)
ret = wret;
}
for (i = 0; i <= orig_level; i++) {
if (path->nodes[i]) {
btrfs_block_release(root, path->nodes[i]);
}
}
btrfs_free_path(path);
return ret;
}
int btrfs_free_block_groups(struct btrfs_fs_info *info)
{
int ret;
struct btrfs_block_group_cache *cache[8];
int i;
while(1) {
ret = radix_tree_gang_lookup(&info->block_group_radix,
(void **)cache, 0,
ARRAY_SIZE(cache));
if (!ret)
break;
for (i = 0; i < ret; i++) {
radix_tree_delete(&info->block_group_radix,
cache[i]->key.objectid +
cache[i]->key.offset - 1);
kfree(cache[i]);
}
}
return 0;
}
int btrfs_read_block_groups(struct btrfs_root *root)
{
struct btrfs_path *path;
int ret;
int err = 0;
struct btrfs_block_group_item *bi;
struct btrfs_block_group_cache *cache;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_leaf *leaf;
u64 group_size_blocks = BTRFS_BLOCK_GROUP_SIZE / root->blocksize;
u64 used;
root = root->fs_info->extent_root;
key.objectid = 0;
key.offset = group_size_blocks;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while(1) {
ret = btrfs_search_slot(NULL, root->fs_info->extent_root,
&key, path, 0, 0);
if (ret != 0) {
err = ret;
break;
}
leaf = btrfs_buffer_leaf(path->nodes[0]);
btrfs_disk_key_to_cpu(&found_key,
&leaf->items[path->slots[0]].key);
cache = kmalloc(sizeof(*cache), GFP_NOFS);
if (!cache) {
err = -1;
break;
}
bi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_block_group_item);
memcpy(&cache->item, bi, sizeof(*bi));
memcpy(&cache->key, &found_key, sizeof(found_key));
cache->last_alloc = cache->key.objectid;
cache->first_free = cache->key.objectid;
key.objectid = found_key.objectid + found_key.offset;
btrfs_release_path(root, path);
ret = radix_tree_insert(&root->fs_info->block_group_radix,
found_key.objectid +
found_key.offset - 1,
(void *)cache);
BUG_ON(ret);
used = btrfs_block_group_used(bi);
if (used < (key.offset * 2) / 3) {
radix_tree_tag_set(&root->fs_info->block_group_radix,
found_key.objectid +
found_key.offset - 1,
BTRFS_BLOCK_GROUP_AVAIL);
}
if (key.objectid >=
btrfs_super_total_blocks(root->fs_info->disk_super))
break;
}
btrfs_free_path(path);
return 0;
}