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linux/fs/btrfs/ctree.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 "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#include "locking.h"
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int level);
static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *ins_key,
struct btrfs_path *path, int data_size, int extend);
static int push_node_left(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *dst,
struct extent_buffer *src, int empty);
static int balance_node_right(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *dst_buf,
struct extent_buffer *src_buf);
static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot);
inline void btrfs_init_path(struct btrfs_path *p)
{
memset(p, 0, sizeof(*p));
}
struct btrfs_path *btrfs_alloc_path(void)
{
struct btrfs_path *path;
path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
if (path) {
btrfs_init_path(path);
path->reada = 1;
}
return path;
}
void btrfs_free_path(struct btrfs_path *p)
{
btrfs_release_path(NULL, p);
kmem_cache_free(btrfs_path_cachep, p);
}
void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
{
int i;
for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
p->slots[i] = 0;
if (!p->nodes[i])
continue;
if (p->locks[i]) {
btrfs_tree_unlock(p->nodes[i]);
p->locks[i] = 0;
}
free_extent_buffer(p->nodes[i]);
p->nodes[i] = NULL;
}
}
struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
{
struct extent_buffer *eb;
spin_lock(&root->node_lock);
eb = root->node;
extent_buffer_get(eb);
spin_unlock(&root->node_lock);
return eb;
}
struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
{
struct extent_buffer *eb;
while(1) {
eb = btrfs_root_node(root);
btrfs_tree_lock(eb);
spin_lock(&root->node_lock);
if (eb == root->node) {
spin_unlock(&root->node_lock);
break;
}
spin_unlock(&root->node_lock);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
}
return eb;
}
static void add_root_to_dirty_list(struct btrfs_root *root)
{
if (root->track_dirty && list_empty(&root->dirty_list)) {
list_add(&root->dirty_list,
&root->fs_info->dirty_cowonly_roots);
}
}
int btrfs_copy_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer **cow_ret, u64 new_root_objectid)
{
struct extent_buffer *cow;
u32 nritems;
int ret = 0;
int level;
struct btrfs_key first_key;
struct btrfs_root *new_root;
new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
if (!new_root)
return -ENOMEM;
memcpy(new_root, root, sizeof(*new_root));
new_root->root_key.objectid = new_root_objectid;
WARN_ON(root->ref_cows && trans->transid !=
root->fs_info->running_transaction->transid);
WARN_ON(root->ref_cows && trans->transid != root->last_trans);
level = btrfs_header_level(buf);
nritems = btrfs_header_nritems(buf);
if (nritems) {
if (level == 0)
btrfs_item_key_to_cpu(buf, &first_key, 0);
else
btrfs_node_key_to_cpu(buf, &first_key, 0);
} else {
first_key.objectid = 0;
}
cow = btrfs_alloc_free_block(trans, new_root, buf->len,
new_root_objectid,
trans->transid, first_key.objectid,
level, buf->start, 0);
if (IS_ERR(cow)) {
kfree(new_root);
return PTR_ERR(cow);
}
copy_extent_buffer(cow, buf, 0, 0, cow->len);
btrfs_set_header_bytenr(cow, cow->start);
btrfs_set_header_generation(cow, trans->transid);
btrfs_set_header_owner(cow, new_root_objectid);
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
WARN_ON(btrfs_header_generation(buf) > trans->transid);
ret = btrfs_inc_ref(trans, new_root, buf, 0);
kfree(new_root);
if (ret)
return ret;
btrfs_mark_buffer_dirty(cow);
*cow_ret = cow;
return 0;
}
int __btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret,
u64 search_start, u64 empty_size,
u64 prealloc_dest)
{
u64 root_gen;
struct extent_buffer *cow;
u32 nritems;
int ret = 0;
int different_trans = 0;
int level;
int unlock_orig = 0;
struct btrfs_key first_key;
if (*cow_ret == buf)
unlock_orig = 1;
WARN_ON(!btrfs_tree_locked(buf));
if (root->ref_cows) {
root_gen = trans->transid;
} else {
root_gen = 0;
}
WARN_ON(root->ref_cows && trans->transid !=
root->fs_info->running_transaction->transid);
WARN_ON(root->ref_cows && trans->transid != root->last_trans);
level = btrfs_header_level(buf);
nritems = btrfs_header_nritems(buf);
if (nritems) {
if (level == 0)
btrfs_item_key_to_cpu(buf, &first_key, 0);
else
btrfs_node_key_to_cpu(buf, &first_key, 0);
} else {
first_key.objectid = 0;
}
if (prealloc_dest) {
struct btrfs_key ins;
ins.objectid = prealloc_dest;
ins.offset = buf->len;
ins.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_alloc_reserved_extent(trans, root,
root->root_key.objectid,
root_gen, level,
first_key.objectid,
&ins);
BUG_ON(ret);
cow = btrfs_init_new_buffer(trans, root, prealloc_dest,
buf->len);
} else {
cow = btrfs_alloc_free_block(trans, root, buf->len,
root->root_key.objectid,
root_gen, first_key.objectid,
level, search_start, empty_size);
}
if (IS_ERR(cow))
return PTR_ERR(cow);
copy_extent_buffer(cow, buf, 0, 0, cow->len);
btrfs_set_header_bytenr(cow, cow->start);
btrfs_set_header_generation(cow, trans->transid);
btrfs_set_header_owner(cow, root->root_key.objectid);
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
WARN_ON(btrfs_header_generation(buf) > trans->transid);
if (btrfs_header_generation(buf) != trans->transid) {
different_trans = 1;
ret = btrfs_inc_ref(trans, root, buf, 1);
if (ret)
return ret;
} else {
clean_tree_block(trans, root, buf);
}
if (buf == root->node) {
WARN_ON(parent && parent != buf);
root_gen = btrfs_header_generation(buf);
spin_lock(&root->node_lock);
root->node = cow;
extent_buffer_get(cow);
spin_unlock(&root->node_lock);
if (buf != root->commit_root) {
btrfs_free_extent(trans, root, buf->start,
buf->len, root->root_key.objectid,
root_gen, 0, 0, 1);
}
free_extent_buffer(buf);
add_root_to_dirty_list(root);
} else {
root_gen = btrfs_header_generation(parent);
btrfs_set_node_blockptr(parent, parent_slot,
cow->start);
WARN_ON(trans->transid == 0);
btrfs_set_node_ptr_generation(parent, parent_slot,
trans->transid);
btrfs_mark_buffer_dirty(parent);
WARN_ON(btrfs_header_generation(parent) != trans->transid);
btrfs_free_extent(trans, root, buf->start, buf->len,
btrfs_header_owner(parent), root_gen,
0, 0, 1);
}
if (unlock_orig)
btrfs_tree_unlock(buf);
free_extent_buffer(buf);
btrfs_mark_buffer_dirty(cow);
*cow_ret = cow;
return 0;
}
int btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret, u64 prealloc_dest)
{
u64 search_start;
u64 header_trans;
int ret;
if (trans->transaction != root->fs_info->running_transaction) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->running_transaction->transid);
WARN_ON(1);
}
if (trans->transid != root->fs_info->generation) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->generation);
WARN_ON(1);
}
header_trans = btrfs_header_generation(buf);
spin_lock(&root->fs_info->hash_lock);
if (header_trans == trans->transid &&
!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
*cow_ret = buf;
spin_unlock(&root->fs_info->hash_lock);
WARN_ON(prealloc_dest);
return 0;
}
spin_unlock(&root->fs_info->hash_lock);
search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
ret = __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0,
prealloc_dest);
return ret;
}
static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
{
if (blocknr < other && other - (blocknr + blocksize) < 32768)
return 1;
if (blocknr > other && blocknr - (other + blocksize) < 32768)
return 1;
return 0;
}
/*
* compare two keys in a memcmp fashion
*/
static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
{
struct btrfs_key k1;
btrfs_disk_key_to_cpu(&k1, disk);
if (k1.objectid > k2->objectid)
return 1;
if (k1.objectid < k2->objectid)
return -1;
if (k1.type > k2->type)
return 1;
if (k1.type < k2->type)
return -1;
if (k1.offset > k2->offset)
return 1;
if (k1.offset < k2->offset)
return -1;
return 0;
}
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *parent,
int start_slot, int cache_only, u64 *last_ret,
struct btrfs_key *progress)
{
struct extent_buffer *cur;
u64 blocknr;
u64 gen;
u64 search_start = *last_ret;
u64 last_block = 0;
u64 other;
u32 parent_nritems;
int end_slot;
int i;
int err = 0;
int parent_level;
int uptodate;
u32 blocksize;
int progress_passed = 0;
struct btrfs_disk_key disk_key;
parent_level = btrfs_header_level(parent);
if (cache_only && parent_level != 1)
return 0;
if (trans->transaction != root->fs_info->running_transaction) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->running_transaction->transid);
WARN_ON(1);
}
if (trans->transid != root->fs_info->generation) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->generation);
WARN_ON(1);
}
parent_nritems = btrfs_header_nritems(parent);
blocksize = btrfs_level_size(root, parent_level - 1);
end_slot = parent_nritems;
if (parent_nritems == 1)
return 0;
for (i = start_slot; i < end_slot; i++) {
int close = 1;
if (!parent->map_token) {
map_extent_buffer(parent,
btrfs_node_key_ptr_offset(i),
sizeof(struct btrfs_key_ptr),
&parent->map_token, &parent->kaddr,
&parent->map_start, &parent->map_len,
KM_USER1);
}
btrfs_node_key(parent, &disk_key, i);
if (!progress_passed && comp_keys(&disk_key, progress) < 0)
continue;
progress_passed = 1;
blocknr = btrfs_node_blockptr(parent, i);
gen = btrfs_node_ptr_generation(parent, i);
if (last_block == 0)
last_block = blocknr;
if (i > 0) {
other = btrfs_node_blockptr(parent, i - 1);
close = close_blocks(blocknr, other, blocksize);
}
if (!close && i < end_slot - 2) {
other = btrfs_node_blockptr(parent, i + 1);
close = close_blocks(blocknr, other, blocksize);
}
if (close) {
last_block = blocknr;
continue;
}
if (parent->map_token) {
unmap_extent_buffer(parent, parent->map_token,
KM_USER1);
parent->map_token = NULL;
}
cur = btrfs_find_tree_block(root, blocknr, blocksize);
if (cur)
uptodate = btrfs_buffer_uptodate(cur, gen);
else
uptodate = 0;
if (!cur || !uptodate) {
if (cache_only) {
free_extent_buffer(cur);
continue;
}
if (!cur) {
cur = read_tree_block(root, blocknr,
blocksize, gen);
} else if (!uptodate) {
btrfs_read_buffer(cur, gen);
}
}
if (search_start == 0)
search_start = last_block;
btrfs_tree_lock(cur);
err = __btrfs_cow_block(trans, root, cur, parent, i,
&cur, search_start,
min(16 * blocksize,
(end_slot - i) * blocksize), 0);
if (err) {
btrfs_tree_unlock(cur);
free_extent_buffer(cur);
break;
}
search_start = cur->start;
last_block = cur->start;
*last_ret = search_start;
btrfs_tree_unlock(cur);
free_extent_buffer(cur);
}
if (parent->map_token) {
unmap_extent_buffer(parent, parent->map_token,
KM_USER1);
parent->map_token = NULL;
}
return err;
}
/*
* The leaf data grows from end-to-front in the node.
* this returns the address of the start of the last item,
* which is the stop of the leaf data stack
*/
static inline unsigned int leaf_data_end(struct btrfs_root *root,
struct extent_buffer *leaf)
{
u32 nr = btrfs_header_nritems(leaf);
if (nr == 0)
return BTRFS_LEAF_DATA_SIZE(root);
return btrfs_item_offset_nr(leaf, nr - 1);
}
static int check_node(struct btrfs_root *root, struct btrfs_path *path,
int level)
{
struct extent_buffer *parent = NULL;
struct extent_buffer *node = path->nodes[level];
struct btrfs_disk_key parent_key;
struct btrfs_disk_key node_key;
int parent_slot;
int slot;
struct btrfs_key cpukey;
u32 nritems = btrfs_header_nritems(node);
if (path->nodes[level + 1])
parent = path->nodes[level + 1];
slot = path->slots[level];
BUG_ON(nritems == 0);
if (parent) {
parent_slot = path->slots[level + 1];
btrfs_node_key(parent, &parent_key, parent_slot);
btrfs_node_key(node, &node_key, 0);
BUG_ON(memcmp(&parent_key, &node_key,
sizeof(struct btrfs_disk_key)));
BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
btrfs_header_bytenr(node));
}
BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
if (slot != 0) {
btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
btrfs_node_key(node, &node_key, slot);
BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
}
if (slot < nritems - 1) {
btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
btrfs_node_key(node, &node_key, slot);
BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
}
return 0;
}
static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
int level)
{
struct extent_buffer *leaf = path->nodes[level];
struct extent_buffer *parent = NULL;
int parent_slot;
struct btrfs_key cpukey;
struct btrfs_disk_key parent_key;
struct btrfs_disk_key leaf_key;
int slot = path->slots[0];
u32 nritems = btrfs_header_nritems(leaf);
if (path->nodes[level + 1])
parent = path->nodes[level + 1];
if (nritems == 0)
return 0;
if (parent) {
parent_slot = path->slots[level + 1];
btrfs_node_key(parent, &parent_key, parent_slot);
btrfs_item_key(leaf, &leaf_key, 0);
BUG_ON(memcmp(&parent_key, &leaf_key,
sizeof(struct btrfs_disk_key)));
BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
btrfs_header_bytenr(leaf));
}
#if 0
for (i = 0; nritems > 1 && i < nritems - 2; i++) {
btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
btrfs_item_key(leaf, &leaf_key, i);
if (comp_keys(&leaf_key, &cpukey) >= 0) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad key\n", i);
BUG_ON(1);
}
if (btrfs_item_offset_nr(leaf, i) !=
btrfs_item_end_nr(leaf, i + 1)) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad\n", i);
BUG_ON(1);
}
if (i == 0) {
if (btrfs_item_offset_nr(leaf, i) +
btrfs_item_size_nr(leaf, i) !=
BTRFS_LEAF_DATA_SIZE(root)) {
btrfs_print_leaf(root, leaf);
printk("slot %d first offset bad\n", i);
BUG_ON(1);
}
}
}
if (nritems > 0) {
if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
btrfs_print_leaf(root, leaf);
printk("slot %d bad size \n", nritems - 1);
BUG_ON(1);
}
}
#endif
if (slot != 0 && slot < nritems - 1) {
btrfs_item_key(leaf, &leaf_key, slot);
btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
if (comp_keys(&leaf_key, &cpukey) <= 0) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad key\n", slot);
BUG_ON(1);
}
if (btrfs_item_offset_nr(leaf, slot - 1) !=
btrfs_item_end_nr(leaf, slot)) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad\n", slot);
BUG_ON(1);
}
}
if (slot < nritems - 1) {
btrfs_item_key(leaf, &leaf_key, slot);
btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
if (btrfs_item_offset_nr(leaf, slot) !=
btrfs_item_end_nr(leaf, slot + 1)) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad\n", slot);
BUG_ON(1);
}
}
BUG_ON(btrfs_item_offset_nr(leaf, 0) +
btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
return 0;
}
static int noinline check_block(struct btrfs_root *root,
struct btrfs_path *path, int level)
{
u64 found_start;
return 0;
if (btrfs_header_level(path->nodes[level]) != level)
printk("warning: bad level %Lu wanted %d found %d\n",
path->nodes[level]->start, level,
btrfs_header_level(path->nodes[level]));
found_start = btrfs_header_bytenr(path->nodes[level]);
if (found_start != path->nodes[level]->start) {
printk("warning: bad bytentr %Lu found %Lu\n",
path->nodes[level]->start, found_start);
}
#if 0
struct extent_buffer *buf = path->nodes[level];
if (memcmp_extent_buffer(buf, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(buf),
BTRFS_FSID_SIZE)) {
printk("warning bad block %Lu\n", buf->start);
return 1;
}
#endif
if (level == 0)
return check_leaf(root, path, level);
return check_node(root, path, level);
}
/*
* search for key in the extent_buffer. The items start at offset p,
* and they are item_size apart. There are 'max' items in p.
*
* the slot in the array is returned via slot, and it points to
* the place where you would insert key if it is not found in
* the array.
*
* slot may point to max if the key is bigger than all of the keys
*/
static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
int item_size, struct btrfs_key *key,
int max, int *slot)
{
int low = 0;
int high = max;
int mid;
int ret;
struct btrfs_disk_key *tmp = NULL;
struct btrfs_disk_key unaligned;
unsigned long offset;
char *map_token = NULL;
char *kaddr = NULL;
unsigned long map_start = 0;
unsigned long map_len = 0;
int err;
while(low < high) {
mid = (low + high) / 2;
offset = p + mid * item_size;
if (!map_token || offset < map_start ||
(offset + sizeof(struct btrfs_disk_key)) >
map_start + map_len) {
if (map_token) {
unmap_extent_buffer(eb, map_token, KM_USER0);
map_token = NULL;
}
err = map_extent_buffer(eb, offset,
sizeof(struct btrfs_disk_key),
&map_token, &kaddr,
&map_start, &map_len, KM_USER0);
if (!err) {
tmp = (struct btrfs_disk_key *)(kaddr + offset -
map_start);
} else {
read_extent_buffer(eb, &unaligned,
offset, sizeof(unaligned));
tmp = &unaligned;
}
} else {
tmp = (struct btrfs_disk_key *)(kaddr + offset -
map_start);
}
ret = comp_keys(tmp, key);
if (ret < 0)
low = mid + 1;
else if (ret > 0)
high = mid;
else {
*slot = mid;
if (map_token)
unmap_extent_buffer(eb, map_token, KM_USER0);
return 0;
}
}
*slot = low;
if (map_token)
unmap_extent_buffer(eb, map_token, KM_USER0);
return 1;
}
/*
* simple bin_search frontend that does the right thing for
* leaves vs nodes
*/
static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
int level, int *slot)
{
if (level == 0) {
return generic_bin_search(eb,
offsetof(struct btrfs_leaf, items),
sizeof(struct btrfs_item),
key, btrfs_header_nritems(eb),
slot);
} else {
return generic_bin_search(eb,
offsetof(struct btrfs_node, ptrs),
sizeof(struct btrfs_key_ptr),
key, btrfs_header_nritems(eb),
slot);
}
return -1;
}
static struct extent_buffer *read_node_slot(struct btrfs_root *root,
struct extent_buffer *parent, int slot)
{
int level = btrfs_header_level(parent);
if (slot < 0)
return NULL;
if (slot >= btrfs_header_nritems(parent))
return NULL;
BUG_ON(level == 0);
return read_tree_block(root, btrfs_node_blockptr(parent, slot),
btrfs_level_size(root, level - 1),
btrfs_node_ptr_generation(parent, slot));
}
static int balance_level(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
struct extent_buffer *right = NULL;
struct extent_buffer *mid;
struct extent_buffer *left = NULL;
struct extent_buffer *parent = NULL;
int ret = 0;
int wret;
int pslot;
int orig_slot = path->slots[level];
int err_on_enospc = 0;
u64 orig_ptr;
if (level == 0)
return 0;
mid = path->nodes[level];
WARN_ON(!path->locks[level]);
WARN_ON(btrfs_header_generation(mid) != trans->transid);
orig_ptr = btrfs_node_blockptr(mid, orig_slot);
if (level < BTRFS_MAX_LEVEL - 1)
parent = path->nodes[level + 1];
pslot = path->slots[level + 1];
/*
* deal with the case where there is only one pointer in the root
* by promoting the node below to a root
*/
if (!parent) {
struct extent_buffer *child;
if (btrfs_header_nritems(mid) != 1)
return 0;
/* promote the child to a root */
child = read_node_slot(root, mid, 0);
btrfs_tree_lock(child);
BUG_ON(!child);
ret = btrfs_cow_block(trans, root, child, mid, 0, &child, 0);
BUG_ON(ret);
spin_lock(&root->node_lock);
root->node = child;
spin_unlock(&root->node_lock);
add_root_to_dirty_list(root);
btrfs_tree_unlock(child);
path->locks[level] = 0;
path->nodes[level] = NULL;
clean_tree_block(trans, root, mid);
btrfs_tree_unlock(mid);
/* once for the path */
free_extent_buffer(mid);
ret = btrfs_free_extent(trans, root, mid->start, mid->len,
root->root_key.objectid,
btrfs_header_generation(mid), 0, 0, 1);
/* once for the root ptr */
free_extent_buffer(mid);
return ret;
}
if (btrfs_header_nritems(mid) >
BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
return 0;
if (btrfs_header_nritems(mid) < 2)
err_on_enospc = 1;
left = read_node_slot(root, parent, pslot - 1);
if (left) {
btrfs_tree_lock(left);
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left, 0);
if (wret) {
ret = wret;
goto enospc;
}
}
right = read_node_slot(root, parent, pslot + 1);
if (right) {
btrfs_tree_lock(right);
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right, 0);
if (wret) {
ret = wret;
goto enospc;
}
}
/* first, try to make some room in the middle buffer */
if (left) {
orig_slot += btrfs_header_nritems(left);
wret = push_node_left(trans, root, left, mid, 1);
if (wret < 0)
ret = wret;
if (btrfs_header_nritems(mid) < 2)
err_on_enospc = 1;
}
/*
* then try to empty the right most buffer into the middle
*/
if (right) {
wret = push_node_left(trans, root, mid, right, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
if (btrfs_header_nritems(right) == 0) {
u64 bytenr = right->start;
u64 generation = btrfs_header_generation(parent);
u32 blocksize = right->len;
clean_tree_block(trans, root, right);
btrfs_tree_unlock(right);
free_extent_buffer(right);
right = NULL;
wret = del_ptr(trans, root, path, level + 1, pslot +
1);
if (wret)
ret = wret;
wret = btrfs_free_extent(trans, root, bytenr,
blocksize,
btrfs_header_owner(parent),
generation, 0, 0, 1);
if (wret)
ret = wret;
} else {
struct btrfs_disk_key right_key;
btrfs_node_key(right, &right_key, 0);
btrfs_set_node_key(parent, &right_key, pslot + 1);
btrfs_mark_buffer_dirty(parent);
}
}
if (btrfs_header_nritems(mid) == 1) {
/*
* we're not allowed to leave a node with one item in the
* tree during a delete. A deletion from lower in the tree
* could try to delete the only pointer in this node.
* So, pull some keys from the left.
* There has to be a left pointer at this point because
* otherwise we would have pulled some pointers from the
* right
*/
BUG_ON(!left);
wret = balance_node_right(trans, root, mid, left);
if (wret < 0) {
ret = wret;
goto enospc;
}
if (wret == 1) {
wret = push_node_left(trans, root, left, mid, 1);
if (wret < 0)
ret = wret;
}
BUG_ON(wret == 1);
}
if (btrfs_header_nritems(mid) == 0) {
/* we've managed to empty the middle node, drop it */
u64 root_gen = btrfs_header_generation(parent);
u64 bytenr = mid->start;
u32 blocksize = mid->len;
clean_tree_block(trans, root, mid);
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
mid = NULL;
wret = del_ptr(trans, root, path, level + 1, pslot);
if (wret)
ret = wret;
wret = btrfs_free_extent(trans, root, bytenr, blocksize,
btrfs_header_owner(parent),
root_gen, 0, 0, 1);
if (wret)
ret = wret;
} else {
/* update the parent key to reflect our changes */
struct btrfs_disk_key mid_key;
btrfs_node_key(mid, &mid_key, 0);
btrfs_set_node_key(parent, &mid_key, pslot);
btrfs_mark_buffer_dirty(parent);
}
/* update the path */
if (left) {
if (btrfs_header_nritems(left) > orig_slot) {
extent_buffer_get(left);
/* left was locked after cow */
path->nodes[level] = left;
path->slots[level + 1] -= 1;
path->slots[level] = orig_slot;
if (mid) {
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
}
} else {
orig_slot -= btrfs_header_nritems(left);
path->slots[level] = orig_slot;
}
}
/* double check we haven't messed things up */
check_block(root, path, level);
if (orig_ptr !=
btrfs_node_blockptr(path->nodes[level], path->slots[level]))
BUG();
enospc:
if (right) {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
if (left) {
if (path->nodes[level] != left)
btrfs_tree_unlock(left);
free_extent_buffer(left);
}
return ret;
}
/* returns zero if the push worked, non-zero otherwise */
static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
struct extent_buffer *right = NULL;
struct extent_buffer *mid;
struct extent_buffer *left = NULL;
struct extent_buffer *parent = NULL;
int ret = 0;
int wret;
int pslot;
int orig_slot = path->slots[level];
u64 orig_ptr;
if (level == 0)
return 1;
mid = path->nodes[level];
WARN_ON(btrfs_header_generation(mid) != trans->transid);
orig_ptr = btrfs_node_blockptr(mid, orig_slot);
if (level < BTRFS_MAX_LEVEL - 1)
parent = path->nodes[level + 1];
pslot = path->slots[level + 1];
if (!parent)
return 1;
left = read_node_slot(root, parent, pslot - 1);
/* first, try to make some room in the middle buffer */
if (left) {
u32 left_nr;
btrfs_tree_lock(left);
left_nr = btrfs_header_nritems(left);
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, left, parent,
pslot - 1, &left, 0);
if (ret)
wret = 1;
else {
wret = push_node_left(trans, root,
left, mid, 0);
}
}
if (wret < 0)
ret = wret;
if (wret == 0) {
struct btrfs_disk_key disk_key;
orig_slot += left_nr;
btrfs_node_key(mid, &disk_key, 0);
btrfs_set_node_key(parent, &disk_key, pslot);
btrfs_mark_buffer_dirty(parent);
if (btrfs_header_nritems(left) > orig_slot) {
path->nodes[level] = left;
path->slots[level + 1] -= 1;
path->slots[level] = orig_slot;
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
} else {
orig_slot -=
btrfs_header_nritems(left);
path->slots[level] = orig_slot;
btrfs_tree_unlock(left);
free_extent_buffer(left);
}
return 0;
}
btrfs_tree_unlock(left);
free_extent_buffer(left);
}
right = read_node_slot(root, parent, pslot + 1);
/*
* then try to empty the right most buffer into the middle
*/
if (right) {
u32 right_nr;
btrfs_tree_lock(right);
right_nr = btrfs_header_nritems(right);
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, right,
parent, pslot + 1,
&right, 0);
if (ret)
wret = 1;
else {
wret = balance_node_right(trans, root,
right, mid);
}
}
if (wret < 0)
ret = wret;
if (wret == 0) {
struct btrfs_disk_key disk_key;
btrfs_node_key(right, &disk_key, 0);
btrfs_set_node_key(parent, &disk_key, pslot + 1);
btrfs_mark_buffer_dirty(parent);
if (btrfs_header_nritems(mid) <= orig_slot) {
path->nodes[level] = right;
path->slots[level + 1] += 1;
path->slots[level] = orig_slot -
btrfs_header_nritems(mid);
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
} else {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
return 0;
}
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
return 1;
}
/*
* readahead one full node of leaves
*/
static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
int level, int slot, u64 objectid)
{
struct extent_buffer *node;
struct btrfs_disk_key disk_key;
u32 nritems;
u64 search;
u64 lowest_read;
u64 highest_read;
u64 nread = 0;
int direction = path->reada;
struct extent_buffer *eb;
u32 nr;
u32 blocksize;
u32 nscan = 0;
if (level != 1)
return;
if (!path->nodes[level])
return;
node = path->nodes[level];
search = btrfs_node_blockptr(node, slot);
blocksize = btrfs_level_size(root, level - 1);
eb = btrfs_find_tree_block(root, search, blocksize);
if (eb) {
free_extent_buffer(eb);
return;
}
highest_read = search;
lowest_read = search;
nritems = btrfs_header_nritems(node);
nr = slot;
while(1) {
if (direction < 0) {
if (nr == 0)
break;
nr--;
} else if (direction > 0) {
nr++;
if (nr >= nritems)
break;
}
if (path->reada < 0 && objectid) {
btrfs_node_key(node, &disk_key, nr);
if (btrfs_disk_key_objectid(&disk_key) != objectid)
break;
}
search = btrfs_node_blockptr(node, nr);
if ((search >= lowest_read && search <= highest_read) ||
(search < lowest_read && lowest_read - search <= 32768) ||
(search > highest_read && search - highest_read <= 32768)) {
readahead_tree_block(root, search, blocksize,
btrfs_node_ptr_generation(node, nr));
nread += blocksize;
}
nscan++;
if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
break;
if(nread > (1024 * 1024) || nscan > 128)
break;
if (search < lowest_read)
lowest_read = search;
if (search > highest_read)
highest_read = search;
}
}
static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
{
int i;
int skip_level = level;
int no_skips = 0;
struct extent_buffer *t;
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
if (!path->nodes[i])
break;
if (!path->locks[i])
break;
if (!no_skips && path->slots[i] == 0) {
skip_level = i + 1;
continue;
}
if (!no_skips && path->keep_locks) {
u32 nritems;
t = path->nodes[i];
nritems = btrfs_header_nritems(t);
if (nritems < 1 || path->slots[i] >= nritems - 1) {
skip_level = i + 1;
continue;
}
}
if (skip_level < i && i >= lowest_unlock)
no_skips = 1;
t = path->nodes[i];
if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
btrfs_tree_unlock(t);
path->locks[i] = 0;
}
}
}
/*
* look for key in the tree. path is filled in with nodes along the way
* if key is found, we return zero and you can find the item in the leaf
* level of the path (level 0)
*
* If the key isn't found, the path points to the slot where it should
* be inserted, and 1 is returned. If there are other errors during the
* search a negative error number is returned.
*
* if ins_len > 0, nodes and leaves will be split as we walk down the
* tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
* possible)
*/
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *key, struct btrfs_path *p, int
ins_len, int cow)
{
struct extent_buffer *b;
struct extent_buffer *tmp;
int slot;
int ret;
int level;
int should_reada = p->reada;
int lowest_unlock = 1;
int blocksize;
u8 lowest_level = 0;
u64 blocknr;
u64 gen;
struct btrfs_key prealloc_block;
lowest_level = p->lowest_level;
WARN_ON(lowest_level && ins_len);
WARN_ON(p->nodes[0] != NULL);
WARN_ON(cow && root == root->fs_info->extent_root &&
!mutex_is_locked(&root->fs_info->alloc_mutex));
if (ins_len < 0)
lowest_unlock = 2;
prealloc_block.objectid = 0;
again:
if (p->skip_locking)
b = btrfs_root_node(root);
else
b = btrfs_lock_root_node(root);
while (b) {
level = btrfs_header_level(b);
/*
* setup the path here so we can release it under lock
* contention with the cow code
*/
p->nodes[level] = b;
if (!p->skip_locking)
p->locks[level] = 1;
if (cow) {
int wret;
/* is a cow on this block not required */
spin_lock(&root->fs_info->hash_lock);
if (btrfs_header_generation(b) == trans->transid &&
!btrfs_header_flag(b, BTRFS_HEADER_FLAG_WRITTEN)) {
spin_unlock(&root->fs_info->hash_lock);
goto cow_done;
}
spin_unlock(&root->fs_info->hash_lock);
/* ok, we have to cow, is our old prealloc the right
* size?
*/
if (prealloc_block.objectid &&
prealloc_block.offset != b->len) {
btrfs_free_reserved_extent(root,
prealloc_block.objectid,
prealloc_block.offset);
prealloc_block.objectid = 0;
}
/*
* for higher level blocks, try not to allocate blocks
* with the block and the parent locks held.
*/
if (level > 1 && !prealloc_block.objectid &&
btrfs_path_lock_waiting(p, level)) {
u32 size = b->len;
u64 hint = b->start;
btrfs_release_path(root, p);
ret = btrfs_reserve_extent(trans, root,
size, size, 0,
hint, (u64)-1,
&prealloc_block, 0);
BUG_ON(ret);
goto again;
}
wret = btrfs_cow_block(trans, root, b,
p->nodes[level + 1],
p->slots[level + 1],
&b, prealloc_block.objectid);
prealloc_block.objectid = 0;
if (wret) {
free_extent_buffer(b);
ret = wret;
goto done;
}
}
cow_done:
BUG_ON(!cow && ins_len);
if (level != btrfs_header_level(b))
WARN_ON(1);
level = btrfs_header_level(b);
p->nodes[level] = b;
if (!p->skip_locking)
p->locks[level] = 1;
ret = check_block(root, p, level);
if (ret) {
ret = -1;
goto done;
}
ret = bin_search(b, key, level, &slot);
if (level != 0) {
if (ret && slot > 0)
slot -= 1;
p->slots[level] = slot;
if (ins_len > 0 && btrfs_header_nritems(b) >=
BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
int sret = split_node(trans, root, p, level);
BUG_ON(sret > 0);
if (sret) {
ret = sret;
goto done;
}
b = p->nodes[level];
slot = p->slots[level];
} else if (ins_len < 0) {
int sret = balance_level(trans, root, p,
level);
if (sret) {
ret = sret;
goto done;
}
b = p->nodes[level];
if (!b) {
btrfs_release_path(NULL, p);
goto again;
}
slot = p->slots[level];
BUG_ON(btrfs_header_nritems(b) == 1);
}
unlock_up(p, level, lowest_unlock);
/* this is only true while dropping a snapshot */
if (level == lowest_level) {
break;
}
blocknr = btrfs_node_blockptr(b, slot);
gen = btrfs_node_ptr_generation(b, slot);
blocksize = btrfs_level_size(root, level - 1);
tmp = btrfs_find_tree_block(root, blocknr, blocksize);
if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
b = tmp;
} else {
/*
* reduce lock contention at high levels
* of the btree by dropping locks before
* we read.
*/
if (level > 1) {
btrfs_release_path(NULL, p);
if (tmp)
free_extent_buffer(tmp);
if (should_reada)
reada_for_search(root, p,
level, slot,
key->objectid);
tmp = read_tree_block(root, blocknr,
blocksize, gen);
if (tmp)
free_extent_buffer(tmp);
goto again;
} else {
if (tmp)
free_extent_buffer(tmp);
if (should_reada)
reada_for_search(root, p,
level, slot,
key->objectid);
b = read_node_slot(root, b, slot);
}
}
if (!p->skip_locking)
btrfs_tree_lock(b);
} else {
p->slots[level] = slot;
if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
sizeof(struct btrfs_item) + ins_len) {
int sret = split_leaf(trans, root, key,
p, ins_len, ret == 0);
BUG_ON(sret > 0);
if (sret) {
ret = sret;
goto done;
}
}
unlock_up(p, level, lowest_unlock);
goto done;
}
}
ret = 1;
done:
if (prealloc_block.objectid) {
btrfs_free_reserved_extent(root,
prealloc_block.objectid,
prealloc_block.offset);
}
return ret;
}
/*
* adjust the pointers going up the tree, starting at level
* making sure the right key of each node is points to 'key'.
* This is used after shifting pointers to the left, so it stops
* fixing up pointers when a given leaf/node is not in slot 0 of the
* higher levels
*
* If this fails to write a tree block, it returns -1, but continues
* fixing up the blocks in ram so the tree is consistent.
*/
static int fixup_low_keys(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_disk_key *key, int level)
{
int i;
int ret = 0;
struct extent_buffer *t;
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
int tslot = path->slots[i];
if (!path->nodes[i])
break;
t = path->nodes[i];
btrfs_set_node_key(t, key, tslot);
btrfs_mark_buffer_dirty(path->nodes[i]);
if (tslot != 0)
break;
}
return ret;
}
/*
* try to push data from one node into the next node left in the
* tree.
*
* returns 0 if some ptrs were pushed left, < 0 if there was some horrible
* error, and > 0 if there was no room in the left hand block.
*/
static int push_node_left(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *dst,
struct extent_buffer *src, int empty)
{
int push_items = 0;
int src_nritems;
int dst_nritems;
int ret = 0;
src_nritems = btrfs_header_nritems(src);
dst_nritems = btrfs_header_nritems(dst);
push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
WARN_ON(btrfs_header_generation(src) != trans->transid);
WARN_ON(btrfs_header_generation(dst) != trans->transid);
if (!empty && src_nritems <= 8)
return 1;
if (push_items <= 0) {
return 1;
}
if (empty) {
push_items = min(src_nritems, push_items);
if (push_items < src_nritems) {
/* leave at least 8 pointers in the node if
* we aren't going to empty it
*/
if (src_nritems - push_items < 8) {
if (push_items <= 8)
return 1;
push_items -= 8;
}
}
} else
push_items = min(src_nritems - 8, push_items);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(dst_nritems),
btrfs_node_key_ptr_offset(0),
push_items * sizeof(struct btrfs_key_ptr));
if (push_items < src_nritems) {
memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(push_items),
(src_nritems - push_items) *
sizeof(struct btrfs_key_ptr));
}
btrfs_set_header_nritems(src, src_nritems - push_items);
btrfs_set_header_nritems(dst, dst_nritems + push_items);
btrfs_mark_buffer_dirty(src);
btrfs_mark_buffer_dirty(dst);
return ret;
}
/*
* try to push data from one node into the next node right in the
* tree.
*
* returns 0 if some ptrs were pushed, < 0 if there was some horrible
* error, and > 0 if there was no room in the right hand block.
*
* this will only push up to 1/2 the contents of the left node over
*/
static int balance_node_right(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *dst,
struct extent_buffer *src)
{
int push_items = 0;
int max_push;
int src_nritems;
int dst_nritems;
int ret = 0;
WARN_ON(btrfs_header_generation(src) != trans->transid);
WARN_ON(btrfs_header_generation(dst) != trans->transid);
src_nritems = btrfs_header_nritems(src);
dst_nritems = btrfs_header_nritems(dst);
push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
if (push_items <= 0) {
return 1;
}
if (src_nritems < 4) {
return 1;
}
max_push = src_nritems / 2 + 1;
/* don't try to empty the node */
if (max_push >= src_nritems) {
return 1;
}
if (max_push < push_items)
push_items = max_push;
memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
btrfs_node_key_ptr_offset(0),
(dst_nritems) *
sizeof(struct btrfs_key_ptr));
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(src_nritems - push_items),
push_items * sizeof(struct btrfs_key_ptr));
btrfs_set_header_nritems(src, src_nritems - push_items);
btrfs_set_header_nritems(dst, dst_nritems + push_items);
btrfs_mark_buffer_dirty(src);
btrfs_mark_buffer_dirty(dst);
return ret;
}
/*
* helper function to insert a new root level in the tree.
* A new node is allocated, and a single item is inserted to
* point to the existing root
*
* returns zero on success or < 0 on failure.
*/
static int noinline insert_new_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
u64 root_gen;
u64 lower_gen;
struct extent_buffer *lower;
struct extent_buffer *c;
struct extent_buffer *old;
struct btrfs_disk_key lower_key;
BUG_ON(path->nodes[level]);
BUG_ON(path->nodes[level-1] != root->node);
if (root->ref_cows)
root_gen = trans->transid;
else
root_gen = 0;
lower = path->nodes[level-1];
if (level == 1)
btrfs_item_key(lower, &lower_key, 0);
else
btrfs_node_key(lower, &lower_key, 0);
c = btrfs_alloc_free_block(trans, root, root->nodesize,
root->root_key.objectid,
root_gen, lower_key.objectid, level,
root->node->start, 0);
if (IS_ERR(c))
return PTR_ERR(c);
memset_extent_buffer(c, 0, 0, root->nodesize);
btrfs_set_header_nritems(c, 1);
btrfs_set_header_level(c, level);
btrfs_set_header_bytenr(c, c->start);
btrfs_set_header_generation(c, trans->transid);
btrfs_set_header_owner(c, root->root_key.objectid);
write_extent_buffer(c, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(c),
BTRFS_FSID_SIZE);
write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
(unsigned long)btrfs_header_chunk_tree_uuid(c),
BTRFS_UUID_SIZE);
btrfs_set_node_key(c, &lower_key, 0);
btrfs_set_node_blockptr(c, 0, lower->start);
lower_gen = btrfs_header_generation(lower);
WARN_ON(lower_gen == 0);
btrfs_set_node_ptr_generation(c, 0, lower_gen);
btrfs_mark_buffer_dirty(c);
spin_lock(&root->node_lock);
old = root->node;
root->node = c;
spin_unlock(&root->node_lock);
/* the super has an extra ref to root->node */
free_extent_buffer(old);
add_root_to_dirty_list(root);
extent_buffer_get(c);
path->nodes[level] = c;
path->locks[level] = 1;
path->slots[level] = 0;
if (root->ref_cows && lower_gen != trans->transid) {
struct btrfs_path *back_path = btrfs_alloc_path();
int ret;
mutex_lock(&root->fs_info->alloc_mutex);
ret = btrfs_insert_extent_backref(trans,
root->fs_info->extent_root,
path, lower->start,
root->root_key.objectid,
trans->transid, 0, 0);
BUG_ON(ret);
mutex_unlock(&root->fs_info->alloc_mutex);
btrfs_free_path(back_path);
}
return 0;
}
/*
* worker function to insert a single pointer in a node.
* the node should have enough room for the pointer already
*
* slot and level indicate where you want the key to go, and
* blocknr is the block the key points to.
*
* returns zero on success and < 0 on any error
*/
static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, struct btrfs_disk_key
*key, u64 bytenr, int slot, int level)
{
struct extent_buffer *lower;
int nritems;
BUG_ON(!path->nodes[level]);
lower = path->nodes[level];
nritems = btrfs_header_nritems(lower);
if (slot > nritems)
BUG();
if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
BUG();
if (slot != nritems) {
memmove_extent_buffer(lower,
btrfs_node_key_ptr_offset(slot + 1),
btrfs_node_key_ptr_offset(slot),
(nritems - slot) * sizeof(struct btrfs_key_ptr));
}
btrfs_set_node_key(lower, key, slot);
btrfs_set_node_blockptr(lower, slot, bytenr);
WARN_ON(trans->transid == 0);
btrfs_set_node_ptr_generation(lower, slot, trans->transid);
btrfs_set_header_nritems(lower, nritems + 1);
btrfs_mark_buffer_dirty(lower);
return 0;
}
/*
* split the node at the specified level in path in two.
* The path is corrected to point to the appropriate node after the split
*
* Before splitting this tries to make some room in the node by pushing
* left and right, if either one works, it returns right away.
*
* returns 0 on success and < 0 on failure
*/
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int level)
{
u64 root_gen;
struct extent_buffer *c;
struct extent_buffer *split;
struct btrfs_disk_key disk_key;
int mid;
int ret;
int wret;
u32 c_nritems;
c = path->nodes[level];
WARN_ON(btrfs_header_generation(c) != trans->transid);
if (c == root->node) {
/* trying to split the root, lets make a new one */
ret = insert_new_root(trans, root, path, level + 1);
if (ret)
return ret;
} else {
ret = push_nodes_for_insert(trans, root, path, level);
c = path->nodes[level];
if (!ret && btrfs_header_nritems(c) <
BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
return 0;
if (ret < 0)
return ret;
}
c_nritems = btrfs_header_nritems(c);
if (root->ref_cows)
root_gen = trans->transid;
else
root_gen = 0;
btrfs_node_key(c, &disk_key, 0);
split = btrfs_alloc_free_block(trans, root, root->nodesize,
root->root_key.objectid,
root_gen,
btrfs_disk_key_objectid(&disk_key),
level, c->start, 0);
if (IS_ERR(split))
return PTR_ERR(split);
btrfs_set_header_flags(split, btrfs_header_flags(c));
btrfs_set_header_level(split, btrfs_header_level(c));
btrfs_set_header_bytenr(split, split->start);
btrfs_set_header_generation(split, trans->transid);
btrfs_set_header_owner(split, root->root_key.objectid);
btrfs_set_header_flags(split, 0);
write_extent_buffer(split, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(split),
BTRFS_FSID_SIZE);
write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
(unsigned long)btrfs_header_chunk_tree_uuid(split),
BTRFS_UUID_SIZE);
mid = (c_nritems + 1) / 2;
copy_extent_buffer(split, c,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(mid),
(c_nritems - mid) * sizeof(struct btrfs_key_ptr));
btrfs_set_header_nritems(split, c_nritems - mid);
btrfs_set_header_nritems(c, mid);
ret = 0;
btrfs_mark_buffer_dirty(c);
btrfs_mark_buffer_dirty(split);
btrfs_node_key(split, &disk_key, 0);
wret = insert_ptr(trans, root, path, &disk_key, split->start,
path->slots[level + 1] + 1,
level + 1);
if (wret)
ret = wret;
if (path->slots[level] >= mid) {
path->slots[level] -= mid;
btrfs_tree_unlock(c);
free_extent_buffer(c);
path->nodes[level] = split;
path->slots[level + 1] += 1;
} else {
btrfs_tree_unlock(split);
free_extent_buffer(split);
}
return ret;
}
/*
* how many bytes are required to store the items in a leaf. start
* and nr indicate which items in the leaf to check. This totals up the
* space used both by the item structs and the item data
*/
static int leaf_space_used(struct extent_buffer *l, int start, int nr)
{
int data_len;
int nritems = btrfs_header_nritems(l);
int end = min(nritems, start + nr) - 1;
if (!nr)
return 0;
data_len = btrfs_item_end_nr(l, start);
data_len = data_len - btrfs_item_offset_nr(l, end);
data_len += sizeof(struct btrfs_item) * nr;
WARN_ON(data_len < 0);
return data_len;
}
/*
* The space between the end of the leaf items and
* the start of the leaf data. IOW, how much room
* the leaf has left for both items and data
*/
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
{
int nritems = btrfs_header_nritems(leaf);
int ret;
ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
if (ret < 0) {
printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
leaf_space_used(leaf, 0, nritems), nritems);
}
return ret;
}
/*
* push some data in the path leaf to the right, trying to free up at
* least data_size bytes. returns zero if the push worked, nonzero otherwise
*
* returns 1 if the push failed because the other node didn't have enough
* room, 0 if everything worked out and < 0 if there were major errors.
*/
static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int data_size,
int empty)
{
struct extent_buffer *left = path->nodes[0];
struct extent_buffer *right;
struct extent_buffer *upper;
struct btrfs_disk_key disk_key;
int slot;
u32 i;
int free_space;
int push_space = 0;
int push_items = 0;
struct btrfs_item *item;
u32 left_nritems;
u32 nr;
u32 right_nritems;
u32 data_end;
u32 this_item_size;
int ret;
slot = path->slots[1];
if (!path->nodes[1]) {
return 1;
}
upper = path->nodes[1];
if (slot >= btrfs_header_nritems(upper) - 1)
return 1;
WARN_ON(!btrfs_tree_locked(path->nodes[1]));
right = read_node_slot(root, upper, slot + 1);
btrfs_tree_lock(right);
free_space = btrfs_leaf_free_space(root, right);
if (free_space < data_size + sizeof(struct btrfs_item))
goto out_unlock;
/* cow and double check */
ret = btrfs_cow_block(trans, root, right, upper,
slot + 1, &right, 0);
if (ret)
goto out_unlock;
free_space = btrfs_leaf_free_space(root, right);
if (free_space < data_size + sizeof(struct btrfs_item))
goto out_unlock;
left_nritems = btrfs_header_nritems(left);
if (left_nritems == 0)
goto out_unlock;
if (empty)
nr = 0;
else
nr = 1;
i = left_nritems - 1;
while (i >= nr) {
item = btrfs_item_nr(left, i);
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
if (!left->map_token) {
map_extent_buffer(left, (unsigned long)item,
sizeof(struct btrfs_item),
&left->map_token, &left->kaddr,
&left->map_start, &left->map_len,
KM_USER1);
}
this_item_size = btrfs_item_size(left, item);
if (this_item_size + sizeof(*item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(*item);
if (i == 0)
break;
i--;
}
if (left->map_token) {
unmap_extent_buffer(left, left->map_token, KM_USER1);
left->map_token = NULL;
}
if (push_items == 0)
goto out_unlock;
if (!empty && push_items == left_nritems)
WARN_ON(1);
/* push left to right */
right_nritems = btrfs_header_nritems(right);
push_space = btrfs_item_end_nr(left, left_nritems - push_items);
push_space -= leaf_data_end(root, left);
/* make room in the right data area */
data_end = leaf_data_end(root, right);
memmove_extent_buffer(right,
btrfs_leaf_data(right) + data_end - push_space,
btrfs_leaf_data(right) + data_end,
BTRFS_LEAF_DATA_SIZE(root) - data_end);
/* copy from the left data area */
copy_extent_buffer(right, left, btrfs_leaf_data(right) +
BTRFS_LEAF_DATA_SIZE(root) - push_space,
btrfs_leaf_data(left) + leaf_data_end(root, left),
push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
btrfs_item_nr_offset(0),
right_nritems * sizeof(struct btrfs_item));
/* copy the items from left to right */
copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(left_nritems - push_items),
push_items * sizeof(struct btrfs_item));
/* update the item pointers */
right_nritems += push_items;
btrfs_set_header_nritems(right, right_nritems);
push_space = BTRFS_LEAF_DATA_SIZE(root);
for (i = 0; i < right_nritems; i++) {
item = btrfs_item_nr(right, i);
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
push_space -= btrfs_item_size(right, item);
btrfs_set_item_offset(right, item, push_space);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
left_nritems -= push_items;
btrfs_set_header_nritems(left, left_nritems);
if (left_nritems)
btrfs_mark_buffer_dirty(left);
btrfs_mark_buffer_dirty(right);
btrfs_item_key(right, &disk_key, 0);
btrfs_set_node_key(upper, &disk_key, slot + 1);
btrfs_mark_buffer_dirty(upper);
/* then fixup the leaf pointer in the path */
if (path->slots[0] >= left_nritems) {
path->slots[0] -= left_nritems;
if (btrfs_header_nritems(path->nodes[0]) == 0)
clean_tree_block(trans, root, path->nodes[0]);
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[1] += 1;
} else {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
return 0;
out_unlock:
btrfs_tree_unlock(right);
free_extent_buffer(right);
return 1;
}
/*
* push some data in the path leaf to the left, trying to free up at
* least data_size bytes. returns zero if the push worked, nonzero otherwise
*/
static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int data_size,
int empty)
{
struct btrfs_disk_key disk_key;
struct extent_buffer *right = path->nodes[0];
struct extent_buffer *left;
int slot;
int i;
int free_space;
int push_space = 0;
int push_items = 0;
struct btrfs_item *item;
u32 old_left_nritems;
u32 right_nritems;
u32 nr;
int ret = 0;
int wret;
u32 this_item_size;
u32 old_left_item_size;
slot = path->slots[1];
if (slot == 0)
return 1;
if (!path->nodes[1])
return 1;
right_nritems = btrfs_header_nritems(right);
if (right_nritems == 0) {
return 1;
}
WARN_ON(!btrfs_tree_locked(path->nodes[1]));
left = read_node_slot(root, path->nodes[1], slot - 1);
btrfs_tree_lock(left);
free_space = btrfs_leaf_free_space(root, left);
if (free_space < data_size + sizeof(struct btrfs_item)) {
ret = 1;
goto out;
}
/* cow and double check */
ret = btrfs_cow_block(trans, root, left,
path->nodes[1], slot - 1, &left, 0);
if (ret) {
/* we hit -ENOSPC, but it isn't fatal here */
ret = 1;
goto out;
}
free_space = btrfs_leaf_free_space(root, left);
if (free_space < data_size + sizeof(struct btrfs_item)) {
ret = 1;
goto out;
}
if (empty)
nr = right_nritems;
else
nr = right_nritems - 1;
for (i = 0; i < nr; i++) {
item = btrfs_item_nr(right, i);
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
this_item_size = btrfs_item_size(right, item);
if (this_item_size + sizeof(*item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(*item);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
if (push_items == 0) {
ret = 1;
goto out;
}
if (!empty && push_items == btrfs_header_nritems(right))
WARN_ON(1);
/* push data from right to left */
copy_extent_buffer(left, right,
btrfs_item_nr_offset(btrfs_header_nritems(left)),
btrfs_item_nr_offset(0),
push_items * sizeof(struct btrfs_item));
push_space = BTRFS_LEAF_DATA_SIZE(root) -
btrfs_item_offset_nr(right, push_items -1);
copy_extent_buffer(left, right, btrfs_leaf_data(left) +
leaf_data_end(root, left) - push_space,
btrfs_leaf_data(right) +
btrfs_item_offset_nr(right, push_items - 1),
push_space);
old_left_nritems = btrfs_header_nritems(left);
BUG_ON(old_left_nritems < 0);
old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
u32 ioff;
item = btrfs_item_nr(left, i);
if (!left->map_token) {
map_extent_buffer(left, (unsigned long)item,
sizeof(struct btrfs_item),
&left->map_token, &left->kaddr,
&left->map_start, &left->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(left, item);
btrfs_set_item_offset(left, item,
ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
}
btrfs_set_header_nritems(left, old_left_nritems + push_items);
if (left->map_token) {
unmap_extent_buffer(left, left->map_token, KM_USER1);
left->map_token = NULL;
}
/* fixup right node */
if (push_items > right_nritems) {
printk("push items %d nr %u\n", push_items, right_nritems);
WARN_ON(1);
}
if (push_items < right_nritems) {
push_space = btrfs_item_offset_nr(right, push_items - 1) -
leaf_data_end(root, right);
memmove_extent_buffer(right, btrfs_leaf_data(right) +
BTRFS_LEAF_DATA_SIZE(root) - push_space,
btrfs_leaf_data(right) +
leaf_data_end(root, right), push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(push_items),
(btrfs_header_nritems(right) - push_items) *
sizeof(struct btrfs_item));
}
right_nritems -= push_items;
btrfs_set_header_nritems(right, right_nritems);
push_space = BTRFS_LEAF_DATA_SIZE(root);
for (i = 0; i < right_nritems; i++) {
item = btrfs_item_nr(right, i);
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
push_space = push_space - btrfs_item_size(right, item);
btrfs_set_item_offset(right, item, push_space);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
btrfs_mark_buffer_dirty(left);
if (right_nritems)
btrfs_mark_buffer_dirty(right);
btrfs_item_key(right, &disk_key, 0);
wret = fixup_low_keys(trans, root, path, &disk_key, 1);
if (wret)
ret = wret;
/* then fixup the leaf pointer in the path */
if (path->slots[0] < push_items) {
path->slots[0] += old_left_nritems;
if (btrfs_header_nritems(path->nodes[0]) == 0)
clean_tree_block(trans, root, path->nodes[0]);
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = left;
path->slots[1] -= 1;
} else {
btrfs_tree_unlock(left);
free_extent_buffer(left);
path->slots[0] -= push_items;
}
BUG_ON(path->slots[0] < 0);
return ret;
out:
btrfs_tree_unlock(left);
free_extent_buffer(left);
return ret;
}
/*
* split the path's leaf in two, making sure there is at least data_size
* available for the resulting leaf level of the path.
*
* returns 0 if all went well and < 0 on failure.
*/
static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *ins_key,
struct btrfs_path *path, int data_size, int extend)
{
u64 root_gen;
struct extent_buffer *l;
u32 nritems;
int mid;
int slot;
struct extent_buffer *right;
int space_needed = data_size + sizeof(struct btrfs_item);
int data_copy_size;
int rt_data_off;
int i;
int ret = 0;
int wret;
int double_split;
int num_doubles = 0;
struct btrfs_disk_key disk_key;
if (extend)
space_needed = data_size;
if (root->ref_cows)
root_gen = trans->transid;
else
root_gen = 0;
/* first try to make some room by pushing left and right */
if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
wret = push_leaf_right(trans, root, path, data_size, 0);
if (wret < 0) {
return wret;
}
if (wret) {
wret = push_leaf_left(trans, root, path, data_size, 0);
if (wret < 0)
return wret;
}
l = path->nodes[0];
/* did the pushes work? */
if (btrfs_leaf_free_space(root, l) >= space_needed)
return 0;
}
if (!path->nodes[1]) {
ret = insert_new_root(trans, root, path, 1);
if (ret)
return ret;
}
again:
double_split = 0;
l = path->nodes[0];
slot = path->slots[0];
nritems = btrfs_header_nritems(l);
mid = (nritems + 1)/ 2;
btrfs_item_key(l, &disk_key, 0);
right = btrfs_alloc_free_block(trans, root, root->leafsize,
root->root_key.objectid,
root_gen, disk_key.objectid, 0,
l->start, 0);
if (IS_ERR(right)) {
BUG_ON(1);
return PTR_ERR(right);
}
memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
btrfs_set_header_bytenr(right, right->start);
btrfs_set_header_generation(right, trans->transid);
btrfs_set_header_owner(right, root->root_key.objectid);
btrfs_set_header_level(right, 0);
write_extent_buffer(right, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(right),
BTRFS_FSID_SIZE);
write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
(unsigned long)btrfs_header_chunk_tree_uuid(right),
BTRFS_UUID_SIZE);
if (mid <= slot) {
if (nritems == 1 ||
leaf_space_used(l, mid, nritems - mid) + space_needed >
BTRFS_LEAF_DATA_SIZE(root)) {
if (slot >= nritems) {
btrfs_cpu_key_to_disk(&disk_key, ins_key);
btrfs_set_header_nritems(right, 0);
wret = insert_ptr(trans, root, path,
&disk_key, right->start,
path->slots[1] + 1, 1);
if (wret)
ret = wret;
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] = 0;
path->slots[1] += 1;
btrfs_mark_buffer_dirty(right);
return ret;
}
mid = slot;
if (mid != nritems &&
leaf_space_used(l, mid, nritems - mid) +
space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
double_split = 1;
}
}
} else {
if (leaf_space_used(l, 0, mid + 1) + space_needed >
BTRFS_LEAF_DATA_SIZE(root)) {
if (!extend && slot == 0) {
btrfs_cpu_key_to_disk(&disk_key, ins_key);
btrfs_set_header_nritems(right, 0);
wret = insert_ptr(trans, root, path,
&disk_key,
right->start,
path->slots[1], 1);
if (wret)
ret = wret;
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] = 0;
if (path->slots[1] == 0) {
wret = fixup_low_keys(trans, root,
path, &disk_key, 1);
if (wret)
ret = wret;
}
btrfs_mark_buffer_dirty(right);
return ret;
} else if (extend && slot == 0) {
mid = 1;
} else {
mid = slot;
if (mid != nritems &&
leaf_space_used(l, mid, nritems - mid) +
space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
double_split = 1;
}
}
}
}
nritems = nritems - mid;
btrfs_set_header_nritems(right, nritems);
data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(mid),
nritems * sizeof(struct btrfs_item));
copy_extent_buffer(right, l,
btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
data_copy_size, btrfs_leaf_data(l) +
leaf_data_end(root, l), data_copy_size);
rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
btrfs_item_end_nr(l, mid);
for (i = 0; i < nritems; i++) {
struct btrfs_item *item = btrfs_item_nr(right, i);
u32 ioff;
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(right, item);
btrfs_set_item_offset(right, item, ioff + rt_data_off);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
btrfs_set_header_nritems(l, mid);
ret = 0;
btrfs_item_key(right, &disk_key, 0);
wret = insert_ptr(trans, root, path, &disk_key, right->start,
path->slots[1] + 1, 1);
if (wret)
ret = wret;
btrfs_mark_buffer_dirty(right);
btrfs_mark_buffer_dirty(l);
BUG_ON(path->slots[0] != slot);
if (mid <= slot) {
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] -= mid;
path->slots[1] += 1;
} else {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
BUG_ON(path->slots[0] < 0);
if (double_split) {
BUG_ON(num_doubles != 0);
num_doubles++;
goto again;
}
return ret;
}
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u32 new_size, int from_end)
{
int ret = 0;
int slot;
int slot_orig;
struct extent_buffer *leaf;
struct btrfs_item *item;
u32 nritems;
unsigned int data_end;
unsigned int old_data_start;
unsigned int old_size;
unsigned int size_diff;
int i;
slot_orig = path->slots[0];
leaf = path->nodes[0];
slot = path->slots[0];
old_size = btrfs_item_size_nr(leaf, slot);
if (old_size == new_size)
return 0;
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(root, leaf);
old_data_start = btrfs_item_offset_nr(leaf, slot);
size_diff = old_size - new_size;
BUG_ON(slot < 0);
BUG_ON(slot >= nritems);
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff + size_diff);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
/* shift the data */
if (from_end) {
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + size_diff, btrfs_leaf_data(leaf) +
data_end, old_data_start + new_size - data_end);
} else {
struct btrfs_disk_key disk_key;
u64 offset;
btrfs_item_key(leaf, &disk_key, slot);
if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
unsigned long ptr;
struct btrfs_file_extent_item *fi;
fi = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
fi = (struct btrfs_file_extent_item *)(
(unsigned long)fi - size_diff);
if (btrfs_file_extent_type(leaf, fi) ==
BTRFS_FILE_EXTENT_INLINE) {
ptr = btrfs_item_ptr_offset(leaf, slot);
memmove_extent_buffer(leaf, ptr,
(unsigned long)fi,
offsetof(struct btrfs_file_extent_item,
disk_bytenr));
}
}
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + size_diff, btrfs_leaf_data(leaf) +
data_end, old_data_start - data_end);
offset = btrfs_disk_key_offset(&disk_key);
btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
btrfs_set_item_key(leaf, &disk_key, slot);
if (slot == 0)
fixup_low_keys(trans, root, path, &disk_key, 1);
}
item = btrfs_item_nr(leaf, slot);
btrfs_set_item_size(leaf, item, new_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
return ret;
}
int btrfs_extend_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
u32 data_size)
{
int ret = 0;
int slot;
int slot_orig;
struct extent_buffer *leaf;
struct btrfs_item *item;
u32 nritems;
unsigned int data_end;
unsigned int old_data;
unsigned int old_size;
int i;
slot_orig = path->slots[0];
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(root, leaf);
if (btrfs_leaf_free_space(root, leaf) < data_size) {
btrfs_print_leaf(root, leaf);
BUG();
}
slot = path->slots[0];
old_data = btrfs_item_end_nr(leaf, slot);
BUG_ON(slot < 0);
if (slot >= nritems) {
btrfs_print_leaf(root, leaf);
printk("slot %d too large, nritems %d\n", slot, nritems);
BUG_ON(1);
}
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff - data_size);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
/* shift the data */
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end - data_size, btrfs_leaf_data(leaf) +
data_end, old_data - data_end);
data_end = old_data;
old_size = btrfs_item_size_nr(leaf, slot);
item = btrfs_item_nr(leaf, slot);
btrfs_set_item_size(leaf, item, old_size + data_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
return ret;
}
/*
* Given a key and some data, insert an item into the tree.
* This does all the path init required, making room in the tree if needed.
*/
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *cpu_key, u32 *data_size,
int nr)
{
struct extent_buffer *leaf;
struct btrfs_item *item;
int ret = 0;
int slot;
int slot_orig;
int i;
u32 nritems;
u32 total_size = 0;
u32 total_data = 0;
unsigned int data_end;
struct btrfs_disk_key disk_key;
for (i = 0; i < nr; i++) {
total_data += data_size[i];
}
total_size = total_data + (nr * sizeof(struct btrfs_item));
ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
if (ret == 0) {
return -EEXIST;
}
if (ret < 0)
goto out;
slot_orig = path->slots[0];
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(root, leaf);
if (btrfs_leaf_free_space(root, leaf) <
sizeof(struct btrfs_item) + total_size) {
btrfs_print_leaf(root, leaf);
printk("not enough freespace need %u have %d\n",
total_size, btrfs_leaf_free_space(root, leaf));
BUG();
}
slot = path->slots[0];
BUG_ON(slot < 0);
if (slot != nritems) {
int i;
unsigned int old_data = btrfs_item_end_nr(leaf, slot);
if (old_data < data_end) {
btrfs_print_leaf(root, leaf);
printk("slot %d old_data %d data_end %d\n",
slot, old_data, data_end);
BUG_ON(1);
}
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
WARN_ON(leaf->map_token);
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff - total_data);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
/* shift the items */
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
btrfs_item_nr_offset(slot),
(nritems - slot) * sizeof(struct btrfs_item));
/* shift the data */
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end - total_data, btrfs_leaf_data(leaf) +
data_end, old_data - data_end);
data_end = old_data;
}
/* setup the item for the new data */
for (i = 0; i < nr; i++) {
btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
btrfs_set_item_key(leaf, &disk_key, slot + i);
item = btrfs_item_nr(leaf, slot + i);
btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
data_end -= data_size[i];
btrfs_set_item_size(leaf, item, data_size[i]);
}
btrfs_set_header_nritems(leaf, nritems + nr);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (slot == 0) {
btrfs_cpu_key_to_disk(&disk_key, cpu_key);
ret = fixup_low_keys(trans, root, path, &disk_key, 1);
}
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
out:
return ret;
}
/*
* Given a key and some data, insert an item into the tree.
* This does all the path init required, making room in the tree if needed.
*/
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *cpu_key, void *data, u32
data_size)
{
int ret = 0;
struct btrfs_path *path;
struct extent_buffer *leaf;
unsigned long ptr;
path = btrfs_alloc_path();
BUG_ON(!path);
ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
if (!ret) {
leaf = path->nodes[0];
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, data, ptr, data_size);
btrfs_mark_buffer_dirty(leaf);
}
btrfs_free_path(path);
return ret;
}
/*
* delete the pointer from a given node.
*
* If the delete empties a node, the node is removed from the tree,
* continuing all the way the root if required. The root is converted into
* a leaf if all the nodes are emptied.
*/
static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot)
{
struct extent_buffer *parent = path->nodes[level];
u32 nritems;
int ret = 0;
int wret;
nritems = btrfs_header_nritems(parent);
if (slot != nritems -1) {
memmove_extent_buffer(parent,
btrfs_node_key_ptr_offset(slot),
btrfs_node_key_ptr_offset(slot + 1),
sizeof(struct btrfs_key_ptr) *
(nritems - slot - 1));
}
nritems--;
btrfs_set_header_nritems(parent, nritems);
if (nritems == 0 && parent == root->node) {
BUG_ON(btrfs_header_level(root->node) != 1);
/* just turn the root into a leaf and break */
btrfs_set_header_level(root->node, 0);
} else if (slot == 0) {
struct btrfs_disk_key disk_key;
btrfs_node_key(parent, &disk_key, 0);
wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
if (wret)
ret = wret;
}
btrfs_mark_buffer_dirty(parent);
return ret;
}
/*
* delete the item at the leaf level in path. If that empties
* the leaf, remove it from the tree
*/
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int slot, int nr)
{
struct extent_buffer *leaf;
struct btrfs_item *item;
int last_off;
int dsize = 0;
int ret = 0;
int wret;
int i;
u32 nritems;
leaf = path->nodes[0];
last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
for (i = 0; i < nr; i++)
dsize += btrfs_item_size_nr(leaf, slot + i);
nritems = btrfs_header_nritems(leaf);
if (slot + nr != nritems) {
int i;
int data_end = leaf_data_end(root, leaf);
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + dsize,
btrfs_leaf_data(leaf) + data_end,
last_off - data_end);
for (i = slot + nr; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff + dsize);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
btrfs_item_nr_offset(slot + nr),
sizeof(struct btrfs_item) *
(nritems - slot - nr));
}
btrfs_set_header_nritems(leaf, nritems - nr);
nritems -= nr;
/* delete the leaf if we've emptied it */
if (nritems == 0) {
if (leaf == root->node) {
btrfs_set_header_level(leaf, 0);
} else {
u64 root_gen = btrfs_header_generation(path->nodes[1]);
wret = del_ptr(trans, root, path, 1, path->slots[1]);
if (wret)
ret = wret;
wret = btrfs_free_extent(trans, root,
leaf->start, leaf->len,
btrfs_header_owner(path->nodes[1]),
root_gen, 0, 0, 1);
if (wret)
ret = wret;
}
} else {
int used = leaf_space_used(leaf, 0, nritems);
if (slot == 0) {
struct btrfs_disk_key disk_key;
btrfs_item_key(leaf, &disk_key, 0);
wret = fixup_low_keys(trans, root, path,
&disk_key, 1);
if (wret)
ret = wret;
}
/* delete the leaf if it is mostly empty */
if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
/* push_leaf_left fixes the path.
* make sure the path still points to our leaf
* for possible call to del_ptr below
*/
slot = path->slots[1];
extent_buffer_get(leaf);
wret = push_leaf_left(trans, root, path, 1, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
if (path->nodes[0] == leaf &&
btrfs_header_nritems(leaf)) {
wret = push_leaf_right(trans, root, path, 1, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
}
if (btrfs_header_nritems(leaf) == 0) {
u64 root_gen;
u64 bytenr = leaf->start;
u32 blocksize = leaf->len;
root_gen = btrfs_header_generation(
path->nodes[1]);
wret = del_ptr(trans, root, path, 1, slot);
if (wret)
ret = wret;
free_extent_buffer(leaf);
wret = btrfs_free_extent(trans, root, bytenr,
blocksize,
btrfs_header_owner(path->nodes[1]),
root_gen, 0, 0, 1);
if (wret)
ret = wret;
} else {
/* if we're still in the path, make sure
* we're dirty. Otherwise, one of the
* push_leaf functions must have already
* dirtied this buffer
*/
if (path->nodes[0] == leaf)
btrfs_mark_buffer_dirty(leaf);
free_extent_buffer(leaf);
}
} else {
btrfs_mark_buffer_dirty(leaf);
}
}
return ret;
}
/*
* search the tree again to find a leaf with lesser keys
* returns 0 if it found something or 1 if there are no lesser leaves.
* returns < 0 on io errors.
*/
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
struct btrfs_key key;
struct btrfs_disk_key found_key;
int ret;
btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
if (key.offset > 0)
key.offset--;
else if (key.type > 0)
key.type--;
else if (key.objectid > 0)
key.objectid--;
else
return 1;
btrfs_release_path(root, path);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
return ret;
btrfs_item_key(path->nodes[0], &found_key, 0);
ret = comp_keys(&found_key, &key);
if (ret < 0)
return 0;
return 1;
}
/*
* A helper function to walk down the tree starting at min_key, and looking
* for nodes or leaves that are either in cache or have a minimum
* transaction id. This is used by the btree defrag code, but could
* also be used to search for blocks that have changed since a given
* transaction id.
*
* This does not cow, but it does stuff the starting key it finds back
* into min_key, so you can call btrfs_search_slot with cow=1 on the
* key and get a writable path.
*
* This does lock as it descends, and path->keep_locks should be set
* to 1 by the caller.
*
* This honors path->lowest_level to prevent descent past a given level
* of the tree.
*
* returns zero if something useful was found, < 0 on error and 1 if there
* was nothing in the tree that matched the search criteria.
*/
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
struct btrfs_path *path, int cache_only,
u64 min_trans)
{
struct extent_buffer *cur;
struct btrfs_key found_key;
int slot;
int sret;
u32 nritems;
int level;
int ret = 1;
again:
cur = btrfs_lock_root_node(root);
level = btrfs_header_level(cur);
path->nodes[level] = cur;
path->locks[level] = 1;
if (btrfs_header_generation(cur) < min_trans) {
ret = 1;
goto out;
}
while(1) {
nritems = btrfs_header_nritems(cur);
level = btrfs_header_level(cur);
sret = bin_search(cur, min_key, level, &slot);
/* at level = 0, we're done, setup the path and exit */
if (level == 0) {
ret = 0;
path->slots[level] = slot;
btrfs_item_key_to_cpu(cur, &found_key, slot);
goto out;
}
if (sret && slot > 0)
slot--;
/*
* check this node pointer against the cache_only and
* min_trans parameters. If it isn't in cache or is too
* old, skip to the next one.
*/
while(slot < nritems) {
u64 blockptr;
u64 gen;
struct extent_buffer *tmp;
blockptr = btrfs_node_blockptr(cur, slot);
gen = btrfs_node_ptr_generation(cur, slot);
if (gen < min_trans) {
slot++;
continue;
}
if (!cache_only)
break;
tmp = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));
if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
free_extent_buffer(tmp);
break;
}
if (tmp)
free_extent_buffer(tmp);
slot++;
}
/*
* we didn't find a candidate key in this node, walk forward
* and find another one
*/
if (slot >= nritems) {
ret = btrfs_find_next_key(root, path, min_key, level,
cache_only, min_trans);
if (ret == 0) {
btrfs_release_path(root, path);
goto again;
} else {
goto out;
}
}
/* save our key for returning back */
btrfs_node_key_to_cpu(cur, &found_key, slot);
path->slots[level] = slot;
if (level == path->lowest_level) {
ret = 0;
unlock_up(path, level, 1);
goto out;
}
cur = read_node_slot(root, cur, slot);
btrfs_tree_lock(cur);
path->locks[level - 1] = 1;
path->nodes[level - 1] = cur;
unlock_up(path, level, 1);
}
out:
if (ret == 0)
memcpy(min_key, &found_key, sizeof(found_key));
return ret;
}
/*
* this is similar to btrfs_next_leaf, but does not try to preserve
* and fixup the path. It looks for and returns the next key in the
* tree based on the current path and the cache_only and min_trans
* parameters.
*
* 0 is returned if another key is found, < 0 if there are any errors
* and 1 is returned if there are no higher keys in the tree
*
* path->keep_locks should be set to 1 on the search made before
* calling this function.
*/
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *key, int lowest_level,
int cache_only, u64 min_trans)
{
int level = lowest_level;
int slot;
struct extent_buffer *c;
while(level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
return 1;
slot = path->slots[level] + 1;
c = path->nodes[level];
next:
if (slot >= btrfs_header_nritems(c)) {
level++;
if (level == BTRFS_MAX_LEVEL) {
return 1;
}
continue;
}
if (level == 0)
btrfs_item_key_to_cpu(c, key, slot);
else {
u64 blockptr = btrfs_node_blockptr(c, slot);
u64 gen = btrfs_node_ptr_generation(c, slot);
if (cache_only) {
struct extent_buffer *cur;
cur = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));
if (!cur || !btrfs_buffer_uptodate(cur, gen)) {
slot++;
if (cur)
free_extent_buffer(cur);
goto next;
}
free_extent_buffer(cur);
}
if (gen < min_trans) {
slot++;
goto next;
}
btrfs_node_key_to_cpu(c, key, slot);
}
return 0;
}
return 1;
}
/*
* search the tree again to find a leaf with greater keys
* returns 0 if it found something or 1 if there are no greater leaves.
* returns < 0 on io errors.
*/
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
int slot;
int level = 1;
struct extent_buffer *c;
struct extent_buffer *next = NULL;
struct btrfs_key key;
u32 nritems;
int ret;
nritems = btrfs_header_nritems(path->nodes[0]);
if (nritems == 0) {
return 1;
}
btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
btrfs_release_path(root, path);
path->keep_locks = 1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
path->keep_locks = 0;
if (ret < 0)
return ret;
nritems = btrfs_header_nritems(path->nodes[0]);
/*
* by releasing the path above we dropped all our locks. A balance
* could have added more items next to the key that used to be
* at the very end of the block. So, check again here and
* advance the path if there are now more items available.
*/
if (nritems > 0 && path->slots[0] < nritems - 1) {
path->slots[0]++;
goto done;
}
while(level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
return 1;
slot = path->slots[level] + 1;
c = path->nodes[level];
if (slot >= btrfs_header_nritems(c)) {
level++;
if (level == BTRFS_MAX_LEVEL) {
return 1;
}
continue;
}
if (next) {
btrfs_tree_unlock(next);
free_extent_buffer(next);
}
if (level == 1 && (path->locks[1] || path->skip_locking) &&
path->reada)
reada_for_search(root, path, level, slot, 0);
next = read_node_slot(root, c, slot);
if (!path->skip_locking) {
WARN_ON(!btrfs_tree_locked(c));
btrfs_tree_lock(next);
}
break;
}
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
if (path->locks[level])
btrfs_tree_unlock(c);
free_extent_buffer(c);
path->nodes[level] = next;
path->slots[level] = 0;
if (!path->skip_locking)
path->locks[level] = 1;
if (!level)
break;
if (level == 1 && path->locks[1] && path->reada)
reada_for_search(root, path, level, slot, 0);
next = read_node_slot(root, next, 0);
if (!path->skip_locking) {
WARN_ON(!btrfs_tree_locked(path->nodes[level]));
btrfs_tree_lock(next);
}
}
done:
unlock_up(path, 0, 1);
return 0;
}
/*
* this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
* searching until it gets past min_objectid or finds an item of 'type'
*
* returns 0 if something is found, 1 if nothing was found and < 0 on error
*/
int btrfs_previous_item(struct btrfs_root *root,
struct btrfs_path *path, u64 min_objectid,
int type)
{
struct btrfs_key found_key;
struct extent_buffer *leaf;
int ret;
while(1) {
if (path->slots[0] == 0) {
ret = btrfs_prev_leaf(root, path);
if (ret != 0)
return ret;
} else {
path->slots[0]--;
}
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.type == type)
return 0;
}
return 1;
}
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