#include <stdio.h>
#include <stdlib.h>
#include "kerncompat.h"
#include "radix-tree.h"
#include "ctree.h"
#include "disk-io.h"
#include "print-tree.h"
static int find_free_extent(struct ctree_root *orig_root, u64 num_blocks,
u64 search_start, u64 search_end,
struct btrfs_key *ins);
static int finish_current_insert(struct ctree_root *extent_root);
static int run_pending(struct ctree_root *extent_root);
/*
* pending extents are blocks that we're trying to allocate in the extent
* map while trying to grow the map because of other allocations. To avoid
* recursing, they are tagged in the radix tree and cleaned up after
* other allocations are done. The pending tag is also used in the same
* manner for deletes.
*/
#define CTREE_EXTENT_PENDING_DEL 0
static int inc_block_ref(struct ctree_root *root, u64 blocknr)
{
struct ctree_path path;
int ret;
struct btrfs_key key;
struct leaf *l;
struct extent_item *item;
struct btrfs_key ins;
find_free_extent(root->extent_root, 0, 0, (u64)-1, &ins);
init_path(&path);
key.objectid = blocknr;
key.flags = 0;
key.offset = 1;
ret = search_slot(root->extent_root, &key, &path, 0, 1);
if (ret != 0)
BUG();
BUG_ON(ret != 0);
l = &path.nodes[0]->leaf;
item = (struct extent_item *)(l->data + btrfs_item_offset(l->items +
path.slots[0]));
item->refs++;
BUG_ON(list_empty(&path.nodes[0]->dirty));
release_path(root->extent_root, &path);
finish_current_insert(root->extent_root);
run_pending(root->extent_root);
return 0;
}
static int lookup_block_ref(struct ctree_root *root, u64 blocknr, u32 *refs)
{
struct ctree_path path;
int ret;
struct btrfs_key key;
struct leaf *l;
struct extent_item *item;
init_path(&path);
key.objectid = blocknr;
key.flags = 0;
key.offset = 1;
ret = search_slot(root->extent_root, &key, &path, 0, 0);
if (ret != 0)
BUG();
l = &path.nodes[0]->leaf;
item = (struct extent_item *)(l->data +
btrfs_item_offset(l->items +
path.slots[0]));
*refs = item->refs;
release_path(root->extent_root, &path);
return 0;
}
int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf)
{
u64 blocknr;
int i;
if (root == root->extent_root)
return 0;
if (btrfs_is_leaf(&buf->node))
return 0;
for (i = 0; i < btrfs_header_nritems(&buf->node.header); i++) {
blocknr = btrfs_node_blockptr(&buf->node, i);
inc_block_ref(root, blocknr);
}
return 0;
}
int btrfs_finish_extent_commit(struct ctree_root *root)
{
struct ctree_root *extent_root = root->extent_root;
unsigned long gang[8];
int ret;
int i;
while(1) {
ret = radix_tree_gang_lookup(&extent_root->pinned_radix,
(void **)gang, 0,
ARRAY_SIZE(gang));
if (!ret)
break;
for (i = 0; i < ret; i++) {
radix_tree_delete(&extent_root->pinned_radix, gang[i]);
}
}
extent_root->last_insert.objectid = 0;
extent_root->last_insert.offset = 0;
return 0;
}
static int finish_current_insert(struct ctree_root *extent_root)
{
struct btrfs_key ins;
struct extent_item extent_item;
int i;
int ret;
extent_item.refs = 1;
extent_item.owner =
btrfs_header_parentid(&extent_root->node->node.header);
ins.offset = 1;
ins.flags = 0;
for (i = 0; i < extent_root->current_insert.flags; i++) {
ins.objectid = extent_root->current_insert.objectid + i;
ret = insert_item(extent_root, &ins, &extent_item,
sizeof(extent_item));
BUG_ON(ret);
}
extent_root->current_insert.offset = 0;
return 0;
}
/*
* remove an extent from the root, returns 0 on success
*/
int __free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
{
struct ctree_path path;
struct btrfs_key key;
struct ctree_root *extent_root = root->extent_root;
int ret;
struct btrfs_item *item;
struct extent_item *ei;
struct btrfs_key ins;
key.objectid = blocknr;
key.flags = 0;
key.offset = num_blocks;
find_free_extent(root, 0, 0, (u64)-1, &ins);
init_path(&path);
ret = search_slot(extent_root, &key, &path, -1, 1);
if (ret) {
printf("failed to find %Lu\n", key.objectid);
print_tree(extent_root, extent_root->node);
printf("failed to find %Lu\n", key.objectid);
BUG();
}
item = path.nodes[0]->leaf.items + path.slots[0];
ei = (struct extent_item *)(path.nodes[0]->leaf.data +
btrfs_item_offset(item));
BUG_ON(ei->refs == 0);
ei->refs--;
if (ei->refs == 0) {
if (root == extent_root) {
int err;
radix_tree_preload(GFP_KERNEL);
err = radix_tree_insert(&extent_root->pinned_radix,
blocknr, (void *)blocknr);
BUG_ON(err);
radix_tree_preload_end();
}
ret = del_item(extent_root, &path);
if (root != extent_root &&
extent_root->last_insert.objectid < blocknr)
extent_root->last_insert.objectid = blocknr;
if (ret)
BUG();
}
release_path(extent_root, &path);
finish_current_insert(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 ctree_root *extent_root)
{
int ret;
struct tree_buffer *gang[4];
int i;
while(1) {
ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
(void **)gang, 0,
ARRAY_SIZE(gang),
CTREE_EXTENT_PENDING_DEL);
if (!ret)
break;
for (i = 0; i < ret; i++) {
ret = __free_extent(extent_root, gang[i]->blocknr, 1);
radix_tree_tag_clear(&extent_root->cache_radix,
gang[i]->blocknr,
CTREE_EXTENT_PENDING_DEL);
tree_block_release(extent_root, gang[i]);
}
}
return 0;
}
static int run_pending(struct ctree_root *extent_root)
{
while(radix_tree_tagged(&extent_root->cache_radix,
CTREE_EXTENT_PENDING_DEL))
del_pending_extents(extent_root);
return 0;
}
/*
* remove an extent from the root, returns 0 on success
*/
int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
{
struct btrfs_key key;
struct ctree_root *extent_root = root->extent_root;
struct tree_buffer *t;
int pending_ret;
int ret;
if (root == extent_root) {
t = find_tree_block(root, blocknr);
radix_tree_tag_set(&root->cache_radix, blocknr,
CTREE_EXTENT_PENDING_DEL);
return 0;
}
key.objectid = blocknr;
key.flags = 0;
key.offset = num_blocks;
ret = __free_extent(root, blocknr, num_blocks);
pending_ret = run_pending(root->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 = 0
* ins->offset == number of blocks
* Any available blocks before search_start are skipped.
*/
static int find_free_extent(struct ctree_root *orig_root, u64 num_blocks,
u64 search_start, u64 search_end,
struct btrfs_key *ins)
{
struct ctree_path path;
struct btrfs_key key;
int ret;
u64 hole_size = 0;
int slot = 0;
u64 last_block;
u64 test_block;
int start_found;
struct leaf *l;
struct ctree_root * root = orig_root->extent_root;
int total_needed = num_blocks;
total_needed += (btrfs_header_level(&root->node->node.header) + 1) * 3;
if (root->last_insert.objectid > search_start)
search_start = root->last_insert.objectid;
check_failed:
init_path(&path);
ins->objectid = search_start;
ins->offset = 0;
ins->flags = 0;
start_found = 0;
ret = search_slot(root, ins, &path, 0, 0);
if (ret < 0)
goto error;
if (path.slots[0] > 0)
path.slots[0]--;
while (1) {
l = &path.nodes[0]->leaf;
slot = path.slots[0];
if (slot >= btrfs_header_nritems(&l->header)) {
ret = next_leaf(root, &path);
if (ret == 0)
continue;
if (ret < 0)
goto error;
if (!start_found) {
ins->objectid = search_start;
ins->offset = (u64)-1;
start_found = 1;
goto check_pending;
}
ins->objectid = last_block > search_start ?
last_block : search_start;
ins->offset = (u64)-1;
goto check_pending;
}
btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
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 > total_needed) {
ins->objectid = last_block;
ins->offset = hole_size;
goto check_pending;
}
}
}
start_found = 1;
last_block = key.objectid + key.offset;
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
*/
release_path(root, &path);
BUG_ON(ins->objectid < search_start);
for (test_block = ins->objectid;
test_block < ins->objectid + total_needed; test_block++) {
if (radix_tree_lookup(&root->pinned_radix, test_block)) {
search_start = test_block + 1;
goto check_failed;
}
}
BUG_ON(root->current_insert.offset);
root->current_insert.offset = total_needed - num_blocks;
root->current_insert.objectid = ins->objectid + num_blocks;
root->current_insert.flags = 0;
root->last_insert.objectid = ins->objectid;
ins->offset = num_blocks;
return 0;
error:
release_path(root, &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 alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
u64 search_end, u64 owner, struct btrfs_key *ins)
{
int ret;
int pending_ret;
struct ctree_root *extent_root = root->extent_root;
struct extent_item extent_item;
extent_item.refs = 1;
extent_item.owner = owner;
if (root == extent_root) {
BUG_ON(extent_root->current_insert.offset == 0);
BUG_ON(num_blocks != 1);
BUG_ON(extent_root->current_insert.flags ==
extent_root->current_insert.offset);
ins->offset = 1;
ins->objectid = extent_root->current_insert.objectid +
extent_root->current_insert.flags++;
return 0;
}
ret = find_free_extent(root, num_blocks, search_start,
search_end, ins);
if (ret)
return ret;
ret = insert_item(extent_root, ins, &extent_item,
sizeof(extent_item));
finish_current_insert(extent_root);
pending_ret = run_pending(extent_root);
if (ret)
return ret;
if (pending_ret)
return pending_ret;
return 0;
}
/*
* helper function to allocate a block for a given tree
* returns the tree buffer or NULL.
*/
struct tree_buffer *alloc_free_block(struct ctree_root *root)
{
struct btrfs_key ins;
int ret;
struct tree_buffer *buf;
ret = alloc_extent(root, 1, 0, (unsigned long)-1,
btrfs_header_parentid(&root->node->node.header),
&ins);
if (ret) {
BUG();
return NULL;
}
buf = find_tree_block(root, ins.objectid);
dirty_tree_block(root, buf);
return buf;
}
int walk_down_tree(struct ctree_root *root, struct ctree_path *path, int *level)
{
struct tree_buffer *next;
struct tree_buffer *cur;
u64 blocknr;
int ret;
u32 refs;
ret = lookup_block_ref(root, path->nodes[*level]->blocknr, &refs);
BUG_ON(ret);
if (refs > 1)
goto out;
while(*level > 0) {
cur = path->nodes[*level];
if (path->slots[*level] >=
btrfs_header_nritems(&cur->node.header))
break;
blocknr = btrfs_node_blockptr(&cur->node, path->slots[*level]);
ret = lookup_block_ref(root, blocknr, &refs);
if (refs != 1 || *level == 1) {
path->slots[*level]++;
ret = free_extent(root, blocknr, 1);
BUG_ON(ret);
continue;
}
BUG_ON(ret);
next = read_tree_block(root, blocknr);
if (path->nodes[*level-1])
tree_block_release(root, path->nodes[*level-1]);
path->nodes[*level-1] = next;
*level = btrfs_header_level(&next->node.header);
path->slots[*level] = 0;
}
out:
ret = free_extent(root, path->nodes[*level]->blocknr, 1);
tree_block_release(root, path->nodes[*level]);
path->nodes[*level] = NULL;
*level += 1;
BUG_ON(ret);
return 0;
}
int walk_up_tree(struct ctree_root *root, struct ctree_path *path, int *level)
{
int i;
int slot;
int ret;
for(i = *level; i < MAX_LEVEL - 1 && path->nodes[i]; i++) {
slot = path->slots[i];
if (slot <
btrfs_header_nritems(&path->nodes[i]->node.header)- 1) {
path->slots[i]++;
*level = i;
return 0;
} else {
ret = free_extent(root,
path->nodes[*level]->blocknr, 1);
tree_block_release(root, path->nodes[*level]);
path->nodes[*level] = NULL;
*level = i + 1;
BUG_ON(ret);
}
}
return 1;
}
int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
{
int ret;
int level;
struct ctree_path path;
int i;
int orig_level;
init_path(&path);
level = btrfs_header_level(&snap->node.header);
orig_level = level;
path.nodes[level] = snap;
path.slots[level] = 0;
while(1) {
ret = walk_down_tree(root, &path, &level);
if (ret > 0)
break;
ret = walk_up_tree(root, &path, &level);
if (ret > 0)
break;
}
for (i = 0; i <= orig_level; i++) {
if (path.nodes[i]) {
tree_block_release(root, path.nodes[i]);
}
}
return 0;
}
