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ctree.c
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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 "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#include "repair.h"
#include "common/internal.h"
#include "common/messages.h"
#include "common/utils.h"
#include "kernel-lib/sizes.h"
#include "volumes.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, const 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 const struct btrfs_csum {
u16 size;
const char name[14];
} btrfs_csums[] = {
[BTRFS_CSUM_TYPE_CRC32] = { 4, "crc32c" },
[BTRFS_CSUM_TYPE_XXHASH] = { 8, "xxhash64" },
[BTRFS_CSUM_TYPE_SHA256] = { 32, "sha256" },
[BTRFS_CSUM_TYPE_BLAKE2] = { 32, "blake2" },
};
u16 btrfs_super_csum_size(const struct btrfs_super_block *sb)
{
const u16 csum_type = btrfs_super_csum_type(sb);
return btrfs_csums[csum_type].size;
}
const char *btrfs_super_csum_name(u16 csum_type)
{
return btrfs_csums[csum_type].name;
}
size_t btrfs_super_num_csums(void)
{
return ARRAY_SIZE(btrfs_csums);
}
u16 btrfs_csum_type_size(u16 csum_type)
{
return btrfs_csums[csum_type].size;
}
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 = kzalloc(sizeof(struct btrfs_path), GFP_NOFS);
return path;
}
void btrfs_free_path(struct btrfs_path *p)
{
if (!p)
return;
btrfs_release_path(p);
kfree(p);
}
void btrfs_release_path(struct btrfs_path *p)
{
int i;
for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
if (!p->nodes[i])
continue;
free_extent_buffer(p->nodes[i]);
}
memset(p, 0, sizeof(*p));
}
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);
}
}
static void root_add_used(struct btrfs_root *root, u32 size)
{
btrfs_set_root_used(&root->root_item,
btrfs_root_used(&root->root_item) + size);
}
static void root_sub_used(struct btrfs_root *root, u32 size)
{
btrfs_set_root_used(&root->root_item,
btrfs_root_used(&root->root_item) - size);
}
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;
int ret = 0;
int level;
struct btrfs_root *new_root;
struct btrfs_disk_key disk_key;
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);
if (level == 0)
btrfs_item_key(buf, &disk_key, 0);
else
btrfs_node_key(buf, &disk_key, 0);
cow = btrfs_alloc_free_block(trans, new_root, buf->len,
new_root_objectid, &disk_key,
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_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
BTRFS_HEADER_FLAG_RELOC);
if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
else
btrfs_set_header_owner(cow, new_root_objectid);
write_extent_buffer(cow, root->fs_info->fs_devices->metadata_uuid,
btrfs_header_fsid(), BTRFS_FSID_SIZE);
WARN_ON(btrfs_header_generation(buf) > trans->transid);
ret = btrfs_inc_ref(trans, new_root, cow, 0);
kfree(new_root);
if (ret)
return ret;
btrfs_mark_buffer_dirty(cow);
*cow_ret = cow;
return 0;
}
/*
* Create a new tree root, with root objectid set to @objectid.
*
* NOTE: Doesn't support tree with non-zero offset, like data reloc tree.
*/
int btrfs_create_root(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 objectid)
{
struct extent_buffer *node;
struct btrfs_root *new_root;
struct btrfs_disk_key disk_key;
struct btrfs_key location;
struct btrfs_root_item root_item = { 0 };
int ret;
new_root = malloc(sizeof(*new_root));
if (!new_root)
return -ENOMEM;
btrfs_setup_root(new_root, fs_info, objectid);
if (!is_fstree(objectid))
new_root->track_dirty = 1;
add_root_to_dirty_list(new_root);
new_root->objectid = objectid;
new_root->root_key.objectid = objectid;
new_root->root_key.type = BTRFS_ROOT_ITEM_KEY;
new_root->root_key.offset = 0;
node = btrfs_alloc_free_block(trans, new_root, fs_info->nodesize,
objectid, &disk_key, 0, 0, 0);
if (IS_ERR(node)) {
ret = PTR_ERR(node);
error("failed to create root node for tree %llu: %d (%m)",
objectid, ret);
return ret;
}
new_root->node = node;
btrfs_set_header_generation(node, trans->transid);
btrfs_set_header_backref_rev(node, BTRFS_MIXED_BACKREF_REV);
btrfs_clear_header_flag(node,
BTRFS_HEADER_FLAG_RELOC | BTRFS_HEADER_FLAG_WRITTEN);
btrfs_set_header_owner(node, objectid);
btrfs_set_header_nritems(node, 0);
btrfs_set_header_level(node, 0);
ret = btrfs_inc_ref(trans, new_root, node, 0);
if (ret < 0)
goto free;
/*
* Special tree roots may need to modify pointers in @fs_info
* Only quota is supported yet.
*/
switch (objectid) {
case BTRFS_QUOTA_TREE_OBJECTID:
if (fs_info->quota_root) {
error("quota root already exists");
ret = -EEXIST;
goto free;
}
fs_info->quota_root = new_root;
fs_info->quota_enabled = 1;
break;
/*
* Essential trees can't be created by this function, yet.
* As we expect such skeleton exists, or a lot of functions like
* btrfs_alloc_free_block() doesn't work at all
*/
case BTRFS_ROOT_TREE_OBJECTID:
case BTRFS_EXTENT_TREE_OBJECTID:
case BTRFS_CHUNK_TREE_OBJECTID:
case BTRFS_FS_TREE_OBJECTID:
ret = -EEXIST;
goto free;
default:
/* Subvolume trees don't need special handling */
if (is_fstree(objectid))
break;
/* Other special trees are not supported yet */
ret = -ENOTTY;
goto free;
}
btrfs_mark_buffer_dirty(node);
btrfs_set_root_bytenr(&root_item, btrfs_header_bytenr(node));
btrfs_set_root_level(&root_item, 0);
btrfs_set_root_generation(&root_item, trans->transid);
btrfs_set_root_dirid(&root_item, 0);
btrfs_set_root_refs(&root_item, 1);
btrfs_set_root_used(&root_item, fs_info->nodesize);
location.objectid = objectid;
location.type = BTRFS_ROOT_ITEM_KEY;
location.offset = 0;
ret = btrfs_insert_root(trans, fs_info->tree_root, &location, &root_item);
if (ret < 0)
goto free;
return ret;
free:
free_extent_buffer(node);
free(new_root);
return ret;
}
/*
* check if the tree block can be shared by multiple trees
*/
static int btrfs_block_can_be_shared(struct btrfs_root *root,
struct extent_buffer *buf)
{
/*
* Tree blocks not in reference counted trees and tree roots
* are never shared. If a block was allocated after the last
* snapshot and the block was not allocated by tree relocation,
* we know the block is not shared.
*/
if (root->ref_cows &&
buf != root->node && buf != root->commit_root &&
(btrfs_header_generation(buf) <=
btrfs_root_last_snapshot(&root->root_item) ||
btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
return 1;
return 0;
}
static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer *cow)
{
u64 refs;
u64 owner;
u64 flags;
u64 new_flags = 0;
int ret;
/*
* Backrefs update rules:
*
* Always use full backrefs for extent pointers in tree block
* allocated by tree relocation.
*
* If a shared tree block is no longer referenced by its owner
* tree (btrfs_header_owner(buf) == root->root_key.objectid),
* use full backrefs for extent pointers in tree block.
*
* If a tree block is been relocating
* (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
* use full backrefs for extent pointers in tree block.
* The reason for this is some operations (such as drop tree)
* are only allowed for blocks use full backrefs.
*/
if (btrfs_block_can_be_shared(root, buf)) {
ret = btrfs_lookup_extent_info(trans, trans->fs_info,
buf->start,
btrfs_header_level(buf), 1,
&refs, &flags);
BUG_ON(ret);
BUG_ON(refs == 0);
} else {
refs = 1;
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
else
flags = 0;
}
owner = btrfs_header_owner(buf);
BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
owner == BTRFS_TREE_RELOC_OBJECTID);
if (refs > 1) {
if ((owner == root->root_key.objectid ||
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
ret = btrfs_inc_ref(trans, root, buf, 1);
BUG_ON(ret);
if (root->root_key.objectid ==
BTRFS_TREE_RELOC_OBJECTID) {
ret = btrfs_dec_ref(trans, root, buf, 0);
BUG_ON(ret);
ret = btrfs_inc_ref(trans, root, cow, 1);
BUG_ON(ret);
}
new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
} else {
if (root->root_key.objectid ==
BTRFS_TREE_RELOC_OBJECTID)
ret = btrfs_inc_ref(trans, root, cow, 1);
else
ret = btrfs_inc_ref(trans, root, cow, 0);
BUG_ON(ret);
}
if (new_flags != 0) {
ret = btrfs_set_block_flags(trans, buf->start,
btrfs_header_level(buf),
new_flags);
BUG_ON(ret);
}
} else {
if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
if (root->root_key.objectid ==
BTRFS_TREE_RELOC_OBJECTID)
ret = btrfs_inc_ref(trans, root, cow, 1);
else
ret = btrfs_inc_ref(trans, root, cow, 0);
BUG_ON(ret);
ret = btrfs_dec_ref(trans, root, buf, 1);
BUG_ON(ret);
}
clean_tree_block(buf);
}
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)
{
struct extent_buffer *cow;
struct btrfs_disk_key disk_key;
int level;
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);
if (level == 0)
btrfs_item_key(buf, &disk_key, 0);
else
btrfs_node_key(buf, &disk_key, 0);
cow = btrfs_alloc_free_block(trans, root, buf->len,
root->root_key.objectid, &disk_key,
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_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
BTRFS_HEADER_FLAG_RELOC);
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
else
btrfs_set_header_owner(cow, root->root_key.objectid);
write_extent_buffer(cow, root->fs_info->fs_devices->metadata_uuid,
btrfs_header_fsid(), BTRFS_FSID_SIZE);
WARN_ON(!(buf->flags & EXTENT_BAD_TRANSID) &&
btrfs_header_generation(buf) > trans->transid);
update_ref_for_cow(trans, root, buf, cow);
if (buf == root->node) {
root->node = cow;
extent_buffer_get(cow);
btrfs_free_extent(trans, root, buf->start, buf->len,
0, root->root_key.objectid, level, 0);
free_extent_buffer(buf);
add_root_to_dirty_list(root);
} else {
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,
0, root->root_key.objectid, level, 0);
}
if (!list_empty(&buf->recow)) {
list_del_init(&buf->recow);
free_extent_buffer(buf);
}
free_extent_buffer(buf);
btrfs_mark_buffer_dirty(cow);
*cow_ret = cow;
return 0;
}
static inline int should_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf)
{
if (btrfs_header_generation(buf) == trans->transid &&
!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
!(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
return 0;
return 1;
}
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;
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 %llu running %llu\n",
(unsigned long long)trans->transid,
(unsigned long long)root->fs_info->generation);
WARN_ON(1);
}
if (!should_cow_block(trans, root, buf)) {
*cow_ret = buf;
return 0;
}
search_start = buf->start & ~((u64)SZ_1G - 1);
ret = __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0);
return ret;
}
int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
{
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;
}
/*
* compare two keys in a memcmp fashion
*/
static int btrfs_comp_keys(struct btrfs_disk_key *disk,
const struct btrfs_key *k2)
{
struct btrfs_key k1;
btrfs_disk_key_to_cpu(&k1, disk);
return btrfs_comp_cpu_keys(&k1, k2);
}
/*
* 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(const struct btrfs_fs_info *fs_info,
const struct extent_buffer *leaf)
{
u32 nr = btrfs_header_nritems(leaf);
if (nr == 0)
return BTRFS_LEAF_DATA_SIZE(fs_info);
return btrfs_item_offset_nr(leaf, nr - 1);
}
enum btrfs_tree_block_status
btrfs_check_node(struct btrfs_fs_info *fs_info,
struct btrfs_disk_key *parent_key, struct extent_buffer *buf)
{
int i;
struct btrfs_key cpukey;
struct btrfs_disk_key key;
u32 nritems = btrfs_header_nritems(buf);
enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
if (nritems == 0 || nritems > BTRFS_NODEPTRS_PER_BLOCK(fs_info))
goto fail;
ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
if (parent_key && parent_key->type) {
btrfs_node_key(buf, &key, 0);
if (memcmp(parent_key, &key, sizeof(key)))
goto fail;
}
ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
for (i = 0; nritems > 1 && i < nritems - 2; i++) {
btrfs_node_key(buf, &key, i);
btrfs_node_key_to_cpu(buf, &cpukey, i + 1);
if (btrfs_comp_keys(&key, &cpukey) >= 0)
goto fail;
}
return BTRFS_TREE_BLOCK_CLEAN;
fail:
if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) {
if (parent_key)
btrfs_disk_key_to_cpu(&cpukey, parent_key);
else
btrfs_node_key_to_cpu(buf, &cpukey, 0);
btrfs_add_corrupt_extent_record(fs_info, &cpukey,
buf->start, buf->len,
btrfs_header_level(buf));
}
return ret;
}
enum btrfs_tree_block_status
btrfs_check_leaf(struct btrfs_fs_info *fs_info,
struct btrfs_disk_key *parent_key, struct extent_buffer *buf)
{
int i;
struct btrfs_key cpukey;
struct btrfs_disk_key key;
u32 nritems = btrfs_header_nritems(buf);
enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
if (nritems * sizeof(struct btrfs_item) > buf->len) {
fprintf(stderr, "invalid number of items %llu\n",
(unsigned long long)buf->start);
goto fail;
}
if (btrfs_header_level(buf) != 0) {
ret = BTRFS_TREE_BLOCK_INVALID_LEVEL;
fprintf(stderr, "leaf is not a leaf %llu\n",
(unsigned long long)btrfs_header_bytenr(buf));
goto fail;
}
if (btrfs_leaf_free_space(buf) < 0) {
ret = BTRFS_TREE_BLOCK_INVALID_FREE_SPACE;
fprintf(stderr, "leaf free space incorrect %llu %d\n",
(unsigned long long)btrfs_header_bytenr(buf),
btrfs_leaf_free_space(buf));
goto fail;
}
if (nritems == 0)
return BTRFS_TREE_BLOCK_CLEAN;
btrfs_item_key(buf, &key, 0);
if (parent_key && parent_key->type &&
memcmp(parent_key, &key, sizeof(key))) {
ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
fprintf(stderr, "leaf parent key incorrect %llu\n",
(unsigned long long)btrfs_header_bytenr(buf));
goto fail;
}
for (i = 0; nritems > 1 && i < nritems - 1; i++) {
btrfs_item_key(buf, &key, i);
btrfs_item_key_to_cpu(buf, &cpukey, i + 1);
if (btrfs_comp_keys(&key, &cpukey) >= 0) {
ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
fprintf(stderr, "bad key ordering %d %d\n", i, i+1);
goto fail;
}
if (btrfs_item_offset_nr(buf, i) !=
btrfs_item_end_nr(buf, i + 1)) {
ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
fprintf(stderr, "incorrect offsets %u %u\n",
btrfs_item_offset_nr(buf, i),
btrfs_item_end_nr(buf, i + 1));
goto fail;
}
if (i == 0 && btrfs_item_end_nr(buf, i) !=
BTRFS_LEAF_DATA_SIZE(fs_info)) {
ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
fprintf(stderr, "bad item end %u wanted %u\n",
btrfs_item_end_nr(buf, i),
(unsigned)BTRFS_LEAF_DATA_SIZE(fs_info));
goto fail;
}
}
for (i = 0; i < nritems; i++) {
if (btrfs_item_end_nr(buf, i) >
BTRFS_LEAF_DATA_SIZE(fs_info)) {
btrfs_item_key(buf, &key, 0);
btrfs_print_key(&key);
fflush(stdout);
ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
fprintf(stderr, "slot end outside of leaf %llu > %llu\n",
(unsigned long long)btrfs_item_end_nr(buf, i),
(unsigned long long)BTRFS_LEAF_DATA_SIZE(
fs_info));
goto fail;
}
}
return BTRFS_TREE_BLOCK_CLEAN;
fail:
if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) {
if (parent_key)
btrfs_disk_key_to_cpu(&cpukey, parent_key);
else
btrfs_item_key_to_cpu(buf, &cpukey, 0);
btrfs_add_corrupt_extent_record(fs_info, &cpukey,
buf->start, buf->len, 0);
}
return ret;
}
static int noinline check_block(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, int level)
{
struct btrfs_disk_key key;
struct btrfs_disk_key *key_ptr = NULL;
struct extent_buffer *parent;
enum btrfs_tree_block_status ret;
if (path->skip_check_block)
return 0;
if (path->nodes[level + 1]) {
parent = path->nodes[level + 1];
btrfs_node_key(parent, &key, path->slots[level + 1]);
key_ptr = &key;
}
if (level == 0)
ret = btrfs_check_leaf(fs_info, key_ptr, path->nodes[0]);
else
ret = btrfs_check_node(fs_info, key_ptr, path->nodes[level]);
if (ret == BTRFS_TREE_BLOCK_CLEAN)
return 0;
return -EIO;
}
/*
* 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, const struct btrfs_key *key,
int max, int *slot)
{
int low = 0;
int high = max;
int mid;
int ret;
unsigned long offset;
struct btrfs_disk_key *tmp;
while(low < high) {
mid = (low + high) / 2;
offset = p + mid * item_size;
tmp = (struct btrfs_disk_key *)(eb->data + offset);
ret = btrfs_comp_keys(tmp, key);
if (ret < 0)
low = mid + 1;
else if (ret > 0)
high = mid;
else {
*slot = mid;
return 0;
}
}
*slot = low;
return 1;
}
/*
* simple bin_search frontend that does the right thing for
* leaves vs nodes
*/
int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
int *slot)
{
if (btrfs_header_level(eb) == 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);
}
struct extent_buffer *read_node_slot(struct btrfs_fs_info *fs_info,
struct extent_buffer *parent, int slot)
{
struct extent_buffer *ret;
int level = btrfs_header_level(parent);
if (slot < 0)
return NULL;
if (slot >= btrfs_header_nritems(parent))
return NULL;
if (level == 0)
return NULL;
ret = read_tree_block(fs_info, btrfs_node_blockptr(parent, slot),
btrfs_node_ptr_generation(parent, slot));
if (!extent_buffer_uptodate(ret))
return ERR_PTR(-EIO);
if (btrfs_header_level(ret) != level - 1) {
error(
"child eb corrupted: parent bytenr=%llu item=%d parent level=%d child level=%d",
btrfs_header_bytenr(parent), slot,
btrfs_header_level(parent), btrfs_header_level(ret));
free_extent_buffer(ret);
return ERR_PTR(-EIO);
}
return ret;
}
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;
struct btrfs_fs_info *fs_info = root->fs_info;
int ret = 0;
int wret;
int pslot;
int orig_slot = path->slots[level];
u64 orig_ptr;
if (level == 0)
return 0;
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];
}
/*
* 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(fs_info, mid, 0);
BUG_ON(!extent_buffer_uptodate(child));
ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
BUG_ON(ret);
root->node = child;
add_root_to_dirty_list(root);
path->nodes[level] = NULL;
clean_tree_block(mid);
/* once for the path */
free_extent_buffer(mid);
root_sub_used(root, mid->len);
ret = btrfs_free_extent(trans, root, mid->start, mid->len,
0, root->root_key.objectid,
level, 0);
/* once for the root ptr */
free_extent_buffer(mid);
return ret;
}
if (btrfs_header_nritems(mid) >
BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4)
return 0;
left = read_node_slot(fs_info, parent, pslot - 1);
if (extent_buffer_uptodate(left)) {
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left);
if (wret) {
ret = wret;
goto enospc;
}
}
right = read_node_slot(fs_info, parent, pslot + 1);
if (extent_buffer_uptodate(right)) {
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right);
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;
}
/*
* 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;
u32 blocksize = right->len;
clean_tree_block(right);
free_extent_buffer(right);
right = NULL;
wret = btrfs_del_ptr(root, path, level + 1, pslot + 1);
if (wret)
ret = wret;
root_sub_used(root, right->len);
wret = btrfs_free_extent(trans, root, bytenr,
blocksize, 0,
root->root_key.objectid,
level, 0);
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 bytenr = mid->start;
u32 blocksize = mid->len;
clean_tree_block(mid);
free_extent_buffer(mid);
mid = NULL;
wret = btrfs_del_ptr(root, path, level + 1, pslot);
if (wret)
ret = wret;
root_sub_used(root, blocksize);
wret = btrfs_free_extent(trans, root, bytenr, blocksize,
0, root->root_key.objectid,
level, 0);
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);
path->nodes[level] = left;
path->slots[level + 1] -= 1;
path->slots[level] = orig_slot;
if (mid)
free_extent_buffer(mid);