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btrfs-progs/kernel-shared/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 "kernel-lib/bitops.h"
#include "kernel-lib/sizes.h"
#include "kernel-shared/ctree.h"
#include "kernel-shared/disk-io.h"
#include "kernel-shared/transaction.h"
#include "kernel-shared/print-tree.h"
#include "kernel-shared/tree-checker.h"
#include "kernel-shared/volumes.h"
#include "crypto/crc32c.h"
#include "common/internal.h"
#include "common/messages.h"
#include "common/utils.h"
#include "check/repair.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 extent_buffer *dst,
struct extent_buffer *src, int empty);
static int balance_node_right(struct btrfs_trans_handle *trans,
struct extent_buffer *dst_buf,
struct extent_buffer *src_buf);
static const struct btrfs_csums {
u16 size;
const char name[10];
const char driver[12];
} btrfs_csums[] = {
[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" },
[BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" },
[BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b",
.driver = "blake2b-256" },
};
/*
* 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 unsigned int leaf_data_end(const struct extent_buffer *leaf)
{
u32 nr = btrfs_header_nritems(leaf);
if (nr == 0)
return BTRFS_LEAF_DATA_SIZE(leaf->fs_info);
return btrfs_item_offset(leaf, nr - 1);
}
/*
* Move data in a @leaf (using memmove, safe for overlapping ranges).
*
* @leaf: leaf that we're doing a memmove on
* @dst_offset: item data offset we're moving to
* @src_offset: item data offset were' moving from
* @len: length of the data we're moving
*
* Wrapper around memmove_extent_buffer() that takes into account the header on
* the leaf. The btrfs_item offset's start directly after the header, so we
* have to adjust any offsets to account for the header in the leaf. This
* handles that math to simplify the callers.
*/
static inline void memmove_leaf_data(const struct extent_buffer *leaf,
unsigned long dst_offset,
unsigned long src_offset,
unsigned long len)
{
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + dst_offset,
btrfs_item_nr_offset(leaf, 0) + src_offset, len);
}
/*
* Copy item data from @src into @dst at the given @offset.
*
* @dst: destination leaf that we're copying into
* @src: source leaf that we're copying from
* @dst_offset: item data offset we're copying to
* @src_offset: item data offset were' copying from
* @len: length of the data we're copying
*
* Wrapper around copy_extent_buffer() that takes into account the header on
* the leaf. The btrfs_item offset's start directly after the header, so we
* have to adjust any offsets to account for the header in the leaf. This
* handles that math to simplify the callers.
*/
static inline void copy_leaf_data(const struct extent_buffer *dst,
const struct extent_buffer *src,
unsigned long dst_offset,
unsigned long src_offset, unsigned long len)
{
copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, 0) + dst_offset,
btrfs_item_nr_offset(src, 0) + src_offset, len);
}
/*
* Move items in a @leaf (using memmove).
*
* @dst: destination leaf for the items
* @dst_item: the item nr we're copying into
* @src_item: the item nr we're copying from
* @nr_items: the number of items to copy
*
* Wrapper around memmove_extent_buffer() that does the math to get the
* appropriate offsets into the leaf from the item numbers.
*/
static inline void memmove_leaf_items(const struct extent_buffer *leaf,
int dst_item, int src_item, int nr_items)
{
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, dst_item),
btrfs_item_nr_offset(leaf, src_item),
nr_items * sizeof(struct btrfs_item));
}
/*
* Copy items from @src into @dst at the given @offset.
*
* @dst: destination leaf for the items
* @src: source leaf for the items
* @dst_item: the item nr we're copying into
* @src_item: the item nr we're copying from
* @nr_items: the number of items to copy
*
* Wrapper around copy_extent_buffer() that does the math to get the
* appropriate offsets into the leaf from the item numbers.
*/
static inline void copy_leaf_items(const struct extent_buffer *dst,
const struct extent_buffer *src,
int dst_item, int src_item, int nr_items)
{
copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, dst_item),
btrfs_item_nr_offset(src, src_item),
nr_items * sizeof(struct btrfs_item));
}
int btrfs_super_csum_size(const struct btrfs_super_block *sb)
{
const u16 csum_type = btrfs_super_csum_type(sb);
/* csum type is validated at mount time */
return btrfs_csums[csum_type].size;
}
const char *btrfs_super_csum_name(u16 csum_type)
{
/* csum type is validated at mount time */
return btrfs_csums[csum_type].name;
}
/*
* Return driver name if defined, otherwise the name that's also a valid driver
* name
*/
const char *btrfs_super_csum_driver(u16 csum_type)
{
/* csum type is validated at mount time */
return btrfs_csums[csum_type].driver[0] ?
btrfs_csums[csum_type].driver :
btrfs_csums[csum_type].name;
}
size_t __attribute_const__ btrfs_get_num_csums(void)
{
return ARRAY_SIZE(btrfs_csums);
}
u16 btrfs_csum_type_size(u16 csum_type)
{
return btrfs_csums[csum_type].size;
}
u64 btrfs_name_hash(const char *name, int len)
{
return crc32c((u32)~1, name, len);
}
/*
* Figure the key offset of an extended inode ref
*/
u64 btrfs_extref_hash(u64 parent_objectid, const char *name, int len)
{
return (u64)crc32c(parent_objectid, name, len);
}
inline void btrfs_init_path(struct btrfs_path *p)
{
memset(p, 0, sizeof(*p));
}
struct btrfs_path *btrfs_alloc_path(void)
{
might_sleep();
return kzalloc(sizeof(struct btrfs_path), GFP_NOFS);
}
/* this also releases the path */
void btrfs_free_path(struct btrfs_path *p)
{
if (!p)
return;
btrfs_release_path(p);
kfree(p);
}
/*
* path release drops references on the extent buffers in the path
* and it drops any locks held by this path
*
* It is safe to call this on paths that no locks or extent buffers held.
*/
noinline void btrfs_release_path(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_rw(p->nodes[i], p->locks[i]);
p->locks[i] = 0;
}
free_extent_buffer(p->nodes[i]);
p->nodes[i] = NULL;
}
memset(p, 0, sizeof(*p));
}
/*
* We want the transaction abort to print stack trace only for errors where the
* cause could be a bug, eg. due to ENOSPC, and not for common errors that are
* caused by external factors.
*/
bool __cold abort_should_print_stack(int errno)
{
switch (errno) {
case -EIO:
case -EROFS:
case -ENOMEM:
return false;
}
return true;
}
void add_root_to_dirty_list(struct btrfs_root *root)
{
if (test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state) &&
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(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
trans->transid != root->fs_info->running_transaction->transid);
WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
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_tree_block(trans, new_root, buf->len,
new_root_objectid, &disk_key,
level, buf->start, 0,
BTRFS_NESTING_NORMAL);
if (IS_ERR(cow)) {
kfree(new_root);
return PTR_ERR(cow);
}
copy_extent_buffer_full(cow, buf);
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_fsid(cow, root->fs_info->fs_devices->metadata_uuid);
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))
set_bit(BTRFS_ROOT_TRACK_DIRTY, &new_root->state);
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_tree_block(trans, new_root, fs_info->nodesize,
objectid, &disk_key, 0, 0, 0,
BTRFS_NESTING_NORMAL);
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;
memset_extent_buffer(node, 0, 0, sizeof(struct btrfs_header));
btrfs_set_header_bytenr(node, node->start);
btrfs_set_header_generation(node, trans->transid);
btrfs_set_header_backref_rev(node, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(node, objectid);
write_extent_buffer_fsid(node, fs_info->fs_devices->metadata_uuid);
write_extent_buffer_chunk_tree_uuid(node, fs_info->chunk_tree_uuid);
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;
case BTRFS_BLOCK_GROUP_TREE_OBJECTID:
if (fs_info->block_group_root) {
error("bg root already exists");
ret = -EEXIST;
goto free;
}
fs_info->block_group_root = new_root;
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_tree_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 shareable 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 (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
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_disk_extent_flags(trans, 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);
}
btrfs_clear_buffer_dirty(buf);
}
return 0;
}
/*
* does the dirty work in cow of a single block. The parent block (if
* supplied) is updated to point to the new cow copy. The new buffer is marked
* dirty and returned locked. If you modify the block it needs to be marked
* dirty again.
*
* search_start -- an allocation hint for the new block
*
* empty_size -- a hint that you plan on doing more cow. This is the size in
* bytes the allocator should try to find free next to the block it returns.
* This is just a hint and may be ignored by the allocator.
*/
static noinline 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(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
trans->transid != root->fs_info->running_transaction->transid);
WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
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_tree_block(trans, root, buf->len,
root->root_key.objectid, &disk_key,
level, search_start, empty_size,
BTRFS_NESTING_NORMAL);
if (IS_ERR(cow))
return PTR_ERR(cow);
copy_extent_buffer_full(cow, buf);
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_fsid(cow, root->fs_info->fs_devices->metadata_uuid);
WARN_ON(!(buf->flags & EXTENT_BUFFER_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, 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, 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 %llu running %llu\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;
}
/*
* helper function for defrag to decide if two blocks pointed to by a
* node are actually close by
*/
static __attribute__((unused)) 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;
}
/*
* same as comp_keys only with two btrfs_key's
*/
int __pure 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);
}
static int noinline check_block(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, int level)
{
enum btrfs_tree_block_status ret;
if (path->skip_check_block)
return 0;
if (level == 0)
ret = __btrfs_check_leaf(path->nodes[0]);
else
ret = __btrfs_check_node(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_header_owner(parent),
btrfs_node_ptr_generation(parent, slot),
level - 1, NULL);
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 bytenr=%llu child level=%d",
btrfs_header_bytenr(parent), slot, btrfs_header_level(parent),
btrfs_header_bytenr(ret), btrfs_header_level(ret));
free_extent_buffer(ret);
return ERR_PTR(-EIO);
}
return ret;
}
/*
* node level balancing, used to make sure nodes are in proper order for
* item deletion. We balance from the top down, so we have to make sure
* that a deletion won't leave an node completely empty later on.
*/
static noinline int balance_level(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
struct btrfs_fs_info *fs_info = root->fs_info;
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 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;
btrfs_clear_buffer_dirty(mid);
/* once for the path */
free_extent_buffer(mid);
root_sub_used(root, mid->len);
ret = btrfs_free_extent(trans, 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, 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, mid, right, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
if (btrfs_header_nritems(right) == 0) {
u64 bytenr = right->start;
u32 blocksize = right->len;
btrfs_clear_buffer_dirty(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, blocksize);
wret = btrfs_free_extent(trans, 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, mid, left);
if (wret < 0) {
ret = wret;
goto enospc;
}
if (wret == 1) {
wret = push_node_left(trans, 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;
btrfs_clear_buffer_dirty(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, 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);
} else {
orig_slot -= btrfs_header_nritems(left);
path->slots[level] = orig_slot;
}
}
/* double check we haven't messed things up */
check_block(root->fs_info, path, level);
if (orig_ptr !=
btrfs_node_blockptr(path->nodes[level], path->slots[level]))
BUG();
enospc:
if (right)
free_extent_buffer(right);
if (left)
free_extent_buffer(left);
return ret;
}
/* Node balancing for insertion. Here we only split or push nodes around
* when they are completely full. This is also done top down, so we
* have to be pessimistic.
*/
static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
struct btrfs_fs_info *fs_info = root->fs_info;
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];
if (level == 0)
return 1;
mid = path->nodes[level];
WARN_ON(btrfs_header_generation(mid) != trans->transid);
if (level < BTRFS_MAX_LEVEL - 1) {
parent = path->nodes[level + 1];
pslot = path->slots[level + 1];
}
if (!parent)
return 1;
left = read_node_slot(fs_info, parent, pslot - 1);
/* first, try to make some room in the middle buffer */
if (extent_buffer_uptodate(left)) {
u32 left_nr;
left_nr = btrfs_header_nritems(left);
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, left, parent,
pslot - 1, &left);
if (ret)
wret = 1;
else {
wret = push_node_left(trans, 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;
free_extent_buffer(mid);
} else {
orig_slot -=
btrfs_header_nritems(left);
path->slots[level] = orig_slot;
free_extent_buffer(left);
}
return 0;
}
free_extent_buffer(left);
}
right= read_node_slot(fs_info, parent, pslot + 1);
/*
* then try to empty the right most buffer into the middle
*/
if (extent_buffer_uptodate(right)) {
u32 right_nr;
right_nr = btrfs_header_nritems(right);
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root->fs_info) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, right,
parent, pslot + 1,
&right);
if (ret)
wret = 1;
else {
wret = balance_node_right(trans, 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);
free_extent_buffer(mid);
} else {
free_extent_buffer(right);
}
return 0;
}
free_extent_buffer(right);
}
return 1;
}
/*
* readahead one full node of leaves, finding things that are close
* to the block in 'slot', and triggering ra on them.
*/
static void reada_for_search(struct btrfs_fs_info *fs_info,
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 nscan = 0;
if (level != 1)
return;
if (!path->nodes[level])
return;
node = path->nodes[level];
search = btrfs_node_blockptr(node, slot);
eb = btrfs_find_tree_block(fs_info, search, fs_info->nodesize);
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(fs_info, search,
btrfs_node_ptr_generation(node, nr));
nread += fs_info->nodesize;
}
nscan++;
if (path->reada < 2 && (nread > SZ_256K || nscan > 32))
break;
if(nread > SZ_1M || nscan > 128)
break;
if (search < lowest_read)
lowest_read = search;
if (search > highest_read)
highest_read = search;
}
}
int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *found_path,
u64 iobjectid, u64 ioff, u8 key_type,
struct btrfs_key *found_key)
{
int ret;
struct btrfs_key key;
struct extent_buffer *eb;
struct btrfs_path *path;
key.type = key_type;
key.objectid = iobjectid;
key.offset = ioff;
if (found_path == NULL) {
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
} else
path = found_path;
ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
if ((ret < 0) || (found_key == NULL))
goto out;
eb = path->nodes[0];
if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(fs_root, path);
if (ret)
goto out;
eb = path->nodes[0];
}
btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
if (found_key->type != key.type ||
found_key->objectid != key.objectid) {
ret = 1;
goto out;
}
out:
if (path != found_path)
btrfs_free_path(path);
return ret;
}
/*
* 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, const struct btrfs_key *key,
struct btrfs_path *p, int ins_len, int cow)
{
struct extent_buffer *b;
int slot;
int ret;
int level;
int should_reada = p->reada;
struct btrfs_fs_info *fs_info = root->fs_info;
u8 lowest_level = 0;
lowest_level = p->lowest_level;
WARN_ON(lowest_level && ins_len > 0);
WARN_ON(p->nodes[0] != NULL);
again:
b = root->node;
extent_buffer_get(b);
while (b) {
level = btrfs_header_level(b);
if (cow) {
int wret;
wret = btrfs_cow_block(trans, root, b,
p->nodes[level + 1],
p->slots[level + 1],
&b);
if (wret) {
free_extent_buffer(b);
return wret;
}
}
BUG_ON(!cow && ins_len);
if (level != btrfs_header_level(b))
WARN_ON(1);
level = btrfs_header_level(b);
p->nodes[level] = b;
ret = check_block(fs_info, p, level);
if (ret)
return -1;
ret = btrfs_bin_search(b, key, &slot);
if (level != 0) {
if (ret && slot > 0)
slot -= 1;
p->slots[level] = slot;
if ((p->search_for_split || ins_len > 0) &&
btrfs_header_nritems(b) >=
BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) {
int sret = split_node(trans, root, p, level);
BUG_ON(sret > 0);
if (sret)
return sret;
b = p->nodes[level];
slot = p->slots[level];
} else if (ins_len < 0) {
int sret = balance_level(trans, root, p,
level);
if (sret)
return sret;
b = p->nodes[level];
if (!b) {
btrfs_release_path(p);
goto again;
}
slot = p->slots[level];
BUG_ON(btrfs_header_nritems(b) == 1);
}
/* this is only true while dropping a snapshot */
if (level == lowest_level)
break;
if (should_reada)
reada_for_search(fs_info, p, level, slot,
key->objectid);
b = read_node_slot(fs_info, b, slot);
if (!extent_buffer_uptodate(b))
return -EIO;
} else {
p->slots[level] = slot;
if (ins_len > 0 &&
ins_len > btrfs_leaf_free_space(b)) {
int sret = split_leaf(trans, root, key,
p, ins_len, ret == 0);
BUG_ON(sret > 0);
if (sret)
return sret;
}
return ret;
}
}
return 1;
}
/*
* Helper to use instead of search slot if no exact match is needed but
* instead the next or previous item should be returned.
* When find_higher is true, the next higher item is returned, the next lower
* otherwise.
* When return_any and find_higher are both true, and no higher item is found,
* return the next lower instead.
* When return_any is true and find_higher is false, and no lower item is found,
* return the next higher instead.
* It returns 0 if any item is found, 1 if none is found (tree empty), and
* < 0 on error
*/
int btrfs_search_slot_for_read(struct btrfs_root *root,
const struct btrfs_key *key,
struct btrfs_path *p, int find_higher,
int return_any)
{
int ret;
struct extent_buffer *leaf;
again:
ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
if (ret <= 0)
return ret;
/*
* A return value of 1 means the path is at the position where the item
* should be inserted. Normally this is the next bigger item, but in
* case the previous item is the last in a leaf, path points to the
* first free slot in the previous leaf, i.e. at an invalid item.
*/
leaf = p->nodes[0];
if (find_higher) {
if (p->slots[0] >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, p);
if (ret <= 0)
return ret;
if (!return_any)
return 1;
/*
* No higher item found, return the next lower instead
*/
return_any = 0;
find_higher = 0;
btrfs_release_path(p);
goto again;
}
} else {
if (p->slots[0] == 0) {
ret = btrfs_prev_leaf(root, p);
if (ret < 0)
return ret;
if (!ret) {
leaf = p->nodes[0];
if (p->slots[0] == btrfs_header_nritems(leaf))
p->slots[0]--;
return 0;
}
if (!return_any)
return 1;
/*
* No lower item found, return the next higher instead
*/
return_any = 0;
find_higher = 1;
btrfs_release_path(p);
goto again;
} else {
--p->slots[0];
}
}
return 0;
}
/*
* 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
*/
void btrfs_fixup_low_keys( struct btrfs_path *path, struct btrfs_disk_key *key,
int level)
{
int i;
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;
}
}
/*
* update item key.
*
* This function isn't completely safe. It's the caller's responsibility
* that the new key won't break the order
*/
int btrfs_set_item_key_safe(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *new_key)
{
struct btrfs_disk_key disk_key;
struct extent_buffer *eb;
int slot;
eb = path->nodes[0];
slot = path->slots[0];
if (slot > 0) {
btrfs_item_key(eb, &disk_key, slot - 1);
if (btrfs_comp_keys(&disk_key, new_key) >= 0)
return -1;
}
if (slot < btrfs_header_nritems(eb) - 1) {
btrfs_item_key(eb, &disk_key, slot + 1);
if (btrfs_comp_keys(&disk_key, new_key) <= 0)
return -1;
}
btrfs_cpu_key_to_disk(&disk_key, new_key);
btrfs_set_item_key(eb, &disk_key, slot);
btrfs_mark_buffer_dirty(eb);
if (slot == 0)
btrfs_fixup_low_keys(path, &disk_key, 1);
return 0;
}
/*
* update an item key without the safety checks. This is meant to be called by
* fsck only.
*/
void btrfs_set_item_key_unsafe(struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *new_key)
{
struct btrfs_disk_key disk_key;
struct extent_buffer *eb;
int slot;
eb = path->nodes[0];
slot = path->slots[0];
btrfs_cpu_key_to_disk(&disk_key, new_key);
btrfs_set_item_key(eb, &disk_key, slot);
btrfs_mark_buffer_dirty(eb);
if (slot == 0)
btrfs_fixup_low_keys(path, &disk_key, 1);
}
/*
* 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 extent_buffer *dst,
struct extent_buffer *src, int empty)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
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(fs_info) - 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, dst_nritems),
btrfs_node_key_ptr_offset(src, 0),
push_items * sizeof(struct btrfs_key_ptr));
if (push_items < src_nritems) {
memmove_extent_buffer(src, btrfs_node_key_ptr_offset(src, 0),
btrfs_node_key_ptr_offset(src, 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 extent_buffer *dst,
struct extent_buffer *src)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
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(fs_info) - 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(dst, push_items),
btrfs_node_key_ptr_offset(dst, 0),
(dst_nritems) *
sizeof(struct btrfs_key_ptr));
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(dst, 0),
btrfs_node_key_ptr_offset(src, 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 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);
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_tree_block(trans, root, root->fs_info->nodesize,
root->root_key.objectid, &lower_key,
level, root->node->start, 0,
BTRFS_NESTING_NORMAL);
if (IS_ERR(c))
return PTR_ERR(c);
memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
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_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(c, root->root_key.objectid);
root_add_used(root, root->fs_info->nodesize);
write_extent_buffer_fsid(c, root->fs_info->fs_devices->metadata_uuid);
write_extent_buffer_chunk_tree_uuid(c, root->fs_info->chunk_tree_uuid);
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 != trans->transid);
btrfs_set_node_ptr_generation(c, 0, lower_gen);
btrfs_mark_buffer_dirty(c);
old = root->node;
root->node = c;
/* 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->slots[level] = 0;
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->fs_info))
BUG();
if (slot < nritems) {
/* shift the items */
memmove_extent_buffer(lower,
btrfs_node_key_ptr_offset(lower, slot + 1),
btrfs_node_key_ptr_offset(lower, 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)
{
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->fs_info) - 3)
return 0;
if (ret < 0)
return ret;
}
c_nritems = btrfs_header_nritems(c);
mid = (c_nritems + 1) / 2;
btrfs_node_key(c, &disk_key, mid);
split = btrfs_alloc_tree_block(trans, root, root->fs_info->nodesize,
root->root_key.objectid,
&disk_key, level, c->start, 0,
BTRFS_NESTING_NORMAL);
if (IS_ERR(split))
return PTR_ERR(split);
memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
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_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(split, root->root_key.objectid);
write_extent_buffer_fsid(split, root->fs_info->fs_devices->metadata_uuid);
write_extent_buffer_chunk_tree_uuid(split, root->fs_info->chunk_tree_uuid);
root_add_used(root, root->fs_info->nodesize);
copy_extent_buffer(split, c,
btrfs_node_key_ptr_offset(split, 0),
btrfs_node_key_ptr_offset(c, 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);
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;
free_extent_buffer(c);
path->nodes[level] = split;
path->slots[level + 1] += 1;
} else {
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_data_end(l, start);
data_len = data_len - btrfs_item_offset(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 extent_buffer *leaf)
{
int nritems = btrfs_header_nritems(leaf);
u32 leaf_data_size;
int ret;
BUG_ON(!leaf->fs_info);
BUG_ON(leaf->fs_info->nodesize != leaf->len);
leaf_data_size = BTRFS_LEAF_DATA_SIZE(leaf->fs_info);
ret = leaf_data_size - leaf_space_used(leaf, 0 ,nritems);
if (ret < 0) {
printk("leaf free space ret %d, leaf data size %u, used %d nritems %d\n",
ret, leaf_data_size, 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;
struct btrfs_fs_info *fs_info = root->fs_info;
int slot;
u32 i;
int free_space;
int push_space = 0;
int push_items = 0;
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;
right = read_node_slot(fs_info, upper, slot + 1);
if (!extent_buffer_uptodate(right)) {
if (IS_ERR(right))
return PTR_ERR(right);
return -EIO;
}
free_space = btrfs_leaf_free_space(right);
if (free_space < data_size) {
free_extent_buffer(right);
return 1;
}
/* cow and double check */
ret = btrfs_cow_block(trans, root, right, upper,
slot + 1, &right);
if (ret) {
free_extent_buffer(right);
return 1;
}
free_space = btrfs_leaf_free_space(right);
if (free_space < data_size) {
free_extent_buffer(right);
return 1;
}
left_nritems = btrfs_header_nritems(left);
if (left_nritems == 0) {
free_extent_buffer(right);
return 1;
}
if (empty)
nr = 0;
else
nr = 1;
i = left_nritems - 1;
while (i >= nr) {
if (path->slots[0] == i)
push_space += data_size + sizeof(struct btrfs_item);
this_item_size = btrfs_item_size(left, i);
if (this_item_size + sizeof(struct btrfs_item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(struct btrfs_item);
if (i == 0)
break;
i--;
}
if (push_items == 0) {
free_extent_buffer(right);
return 1;
}
if (!empty && push_items == left_nritems)
WARN_ON(1);
/* push left to right */
right_nritems = btrfs_header_nritems(right);
push_space = btrfs_item_data_end(left, left_nritems - push_items);
push_space -= leaf_data_end(left);
/* make room in the right data area */
data_end = leaf_data_end(right);
memmove_extent_buffer(right,
btrfs_item_nr_offset(right, 0) + data_end - push_space,
btrfs_item_nr_offset(right, 0) + data_end,
BTRFS_LEAF_DATA_SIZE(root->fs_info) - data_end);
/* copy from the left data area */
copy_extent_buffer(right, left, btrfs_item_nr_offset(right, 0) +
BTRFS_LEAF_DATA_SIZE(root->fs_info) - push_space,
btrfs_item_nr_offset(left, 0) + leaf_data_end(left), push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(right, push_items),
btrfs_item_nr_offset(right, 0),
right_nritems * sizeof(struct btrfs_item));
/* copy the items from left to right */
copy_extent_buffer(right, left, btrfs_item_nr_offset(right, 0),
btrfs_item_nr_offset(left, 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->fs_info);
for (i = 0; i < right_nritems; i++) {
push_space -= btrfs_item_size(right, i);
btrfs_set_item_offset(right, i, push_space);
}
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;
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[1] += 1;
} else {
free_extent_buffer(right);
}
return 0;
}
/*
* 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;
struct btrfs_fs_info *fs_info = root->fs_info;
int slot;
int i;
int free_space;
int push_space = 0;
int push_items = 0;
u32 old_left_nritems;
u32 right_nritems;
u32 nr;
int ret = 0;
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;
}
left = read_node_slot(fs_info, path->nodes[1], slot - 1);
free_space = btrfs_leaf_free_space(left);
if (free_space < data_size) {
free_extent_buffer(left);
return 1;
}
/* cow and double check */
ret = btrfs_cow_block(trans, root, left,
path->nodes[1], slot - 1, &left);
if (ret) {
/* we hit -ENOSPC, but it isn't fatal here */
free_extent_buffer(left);
return 1;
}
free_space = btrfs_leaf_free_space(left);
if (free_space < data_size) {
free_extent_buffer(left);
return 1;
}
if (empty)
nr = right_nritems;
else
nr = right_nritems - 1;
for (i = 0; i < nr; i++) {
if (path->slots[0] == i)
push_space += data_size + sizeof(struct btrfs_item);
this_item_size = btrfs_item_size(right, i);
if (this_item_size + sizeof(struct btrfs_item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(struct btrfs_item);
}
if (push_items == 0) {
free_extent_buffer(left);
return 1;
}
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(left, btrfs_header_nritems(left)),
btrfs_item_nr_offset(right, 0),
push_items * sizeof(struct btrfs_item));
push_space = BTRFS_LEAF_DATA_SIZE(root->fs_info) -
btrfs_item_offset(right, push_items -1);
copy_extent_buffer(left, right, btrfs_item_nr_offset(left, 0) +
leaf_data_end(left) - push_space,
btrfs_item_nr_offset(right, 0) +
btrfs_item_offset(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(left, old_left_nritems - 1);
for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
u32 ioff;
ioff = btrfs_item_offset(left, i);
btrfs_set_item_offset(left, i,
ioff - (BTRFS_LEAF_DATA_SIZE(root->fs_info) -
old_left_item_size));
}
btrfs_set_header_nritems(left, old_left_nritems + push_items);
/* 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(right, push_items - 1) -
leaf_data_end(right);
memmove_extent_buffer(right, btrfs_item_nr_offset(right, 0) +
BTRFS_LEAF_DATA_SIZE(root->fs_info) -
push_space,
btrfs_item_nr_offset(right, 0) +
leaf_data_end(right), push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(right, 0),
btrfs_item_nr_offset(right, 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->fs_info);
for (i = 0; i < right_nritems; i++) {
push_space = push_space - btrfs_item_size(right, i);
btrfs_set_item_offset(right, i, push_space);
}
btrfs_mark_buffer_dirty(left);
if (right_nritems)
btrfs_mark_buffer_dirty(right);
btrfs_item_key(right, &disk_key, 0);
btrfs_fixup_low_keys(path, &disk_key, 1);
/* then fixup the leaf pointer in the path */
if (path->slots[0] < push_items) {
path->slots[0] += old_left_nritems;
free_extent_buffer(path->nodes[0]);
path->nodes[0] = left;
path->slots[1] -= 1;
} else {
free_extent_buffer(left);
path->slots[0] -= push_items;
}
BUG_ON(path->slots[0] < 0);
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 noinline int copy_for_split(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct extent_buffer *l,
struct extent_buffer *right,
int slot, int mid, int nritems)
{
int data_copy_size;
int rt_data_off;
int i;
int ret = 0;
int wret;
struct btrfs_disk_key disk_key;
nritems = nritems - mid;
btrfs_set_header_nritems(right, nritems);
data_copy_size = btrfs_item_data_end(l, mid) - leaf_data_end(l);
copy_extent_buffer(right, l, btrfs_item_nr_offset(right, 0),
btrfs_item_nr_offset(l, mid),
nritems * sizeof(struct btrfs_item));
copy_extent_buffer(right, l,
btrfs_item_nr_offset(right, 0) +
BTRFS_LEAF_DATA_SIZE(root->fs_info) - data_copy_size,
btrfs_item_nr_offset(l, 0) + leaf_data_end(l), data_copy_size);
rt_data_off = BTRFS_LEAF_DATA_SIZE(root->fs_info) -
btrfs_item_data_end(l, mid);
for (i = 0; i < nritems; i++) {
u32 ioff = btrfs_item_offset(right, i);
btrfs_set_item_offset(right, i, ioff + rt_data_off);
}
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) {
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] -= mid;
path->slots[1] += 1;
} else {
free_extent_buffer(right);
}
BUG_ON(path->slots[0] < 0);
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 noinline 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)
{
struct btrfs_disk_key disk_key;
struct extent_buffer *l;
u32 nritems;
int mid;
int slot;
struct extent_buffer *right;
int ret = 0;
int wret;
int split;
int num_doubles = 0;
l = path->nodes[0];
slot = path->slots[0];
if (extend && data_size + btrfs_item_size(l, slot) +
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info))
return -EOVERFLOW;
/* first try to make some room by pushing left and right */
if (data_size && 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(l) >= data_size)
return 0;
}
if (!path->nodes[1]) {
ret = insert_new_root(trans, root, path, 1);
if (ret)
return ret;
}
again:
split = 1;
l = path->nodes[0];
slot = path->slots[0];
nritems = btrfs_header_nritems(l);
mid = (nritems + 1) / 2;
if (mid <= slot) {
if (nritems == 1 ||
leaf_space_used(l, mid, nritems - mid) + data_size >
BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
if (slot >= nritems) {
split = 0;
} else {
mid = slot;
if (mid != nritems &&
leaf_space_used(l, mid, nritems - mid) +
data_size >
BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
split = 2;
}
}
}
} else {
if (leaf_space_used(l, 0, mid) + data_size >
BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
if (!extend && data_size && slot == 0) {
split = 0;
} else if ((extend || !data_size) && slot == 0) {
mid = 1;
} else {
mid = slot;
if (mid != nritems &&
leaf_space_used(l, mid, nritems - mid) +
data_size >
BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
split = 2 ;
}
}
}
}
if (split == 0)
btrfs_cpu_key_to_disk(&disk_key, ins_key);
else
btrfs_item_key(l, &disk_key, mid);
right = btrfs_alloc_tree_block(trans, root, root->fs_info->nodesize,
root->root_key.objectid,
&disk_key, 0, l->start, 0,
BTRFS_NESTING_NORMAL);
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_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(right, root->root_key.objectid);
btrfs_set_header_level(right, 0);
write_extent_buffer_fsid(right, root->fs_info->fs_devices->metadata_uuid);
write_extent_buffer_chunk_tree_uuid(right, root->fs_info->chunk_tree_uuid);
root_add_used(root, root->fs_info->nodesize);
if (split == 0) {
if (mid <= slot) {
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;
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] = 0;
path->slots[1] += 1;
} else {
btrfs_set_header_nritems(right, 0);
wret = insert_ptr(trans, root, path,
&disk_key,
right->start,
path->slots[1], 1);
if (wret)
ret = wret;
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] = 0;
if (path->slots[1] == 0)
btrfs_fixup_low_keys(path, &disk_key, 1);
}
btrfs_mark_buffer_dirty(right);
return ret;
}
ret = copy_for_split(trans, root, path, l, right, slot, mid, nritems);
BUG_ON(ret);
if (split == 2) {
BUG_ON(num_doubles != 0);
num_doubles++;
goto again;
}
return ret;
}
/*
* This function splits a single item into two items,
* giving 'new_key' to the new item and splitting the
* old one at split_offset (from the start of the item).
*
* The path may be released by this operation. After
* the split, the path is pointing to the old item. The
* new item is going to be in the same node as the old one.
*
* Note, the item being split must be smaller enough to live alone on
* a tree block with room for one extra struct btrfs_item
*
* This allows us to split the item in place, keeping a lock on the
* leaf the entire time.
*/
int btrfs_split_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *new_key,
unsigned long split_offset)
{
u32 item_size;
struct extent_buffer *leaf;
struct btrfs_key orig_key;
int ret = 0;
int slot;
u32 nritems;
u32 orig_offset;
struct btrfs_disk_key disk_key;
char *buf;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &orig_key, path->slots[0]);
if (btrfs_leaf_free_space(leaf) >=
sizeof(struct btrfs_item))
goto split;
item_size = btrfs_item_size(leaf, path->slots[0]);
btrfs_release_path(path);
path->search_for_split = 1;
ret = btrfs_search_slot(trans, root, &orig_key, path, 0, 1);
path->search_for_split = 0;
/* if our item isn't there or got smaller, return now */
if (ret != 0 || item_size != btrfs_item_size(path->nodes[0],
path->slots[0])) {
return -EAGAIN;
}
ret = split_leaf(trans, root, &orig_key, path, 0, 0);
BUG_ON(ret);
BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item));
leaf = path->nodes[0];
split:
orig_offset = btrfs_item_offset(leaf, path->slots[0]);
item_size = btrfs_item_size(leaf, path->slots[0]);
buf = kmalloc(item_size, GFP_NOFS);
BUG_ON(!buf);
read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
path->slots[0]), item_size);
slot = path->slots[0] + 1;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
if (slot < nritems) {
/* shift the items */
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, slot + 1),
btrfs_item_nr_offset(leaf, slot),
(nritems - slot) * sizeof(struct btrfs_item));
}
btrfs_cpu_key_to_disk(&disk_key, new_key);
btrfs_set_item_key(leaf, &disk_key, slot);
btrfs_set_item_offset(leaf, slot, orig_offset);
btrfs_set_item_size(leaf, slot, item_size - split_offset);
btrfs_set_item_offset(leaf, path->slots[0],
orig_offset + item_size - split_offset);
btrfs_set_item_size(leaf, path->slots[0], split_offset);
btrfs_set_header_nritems(leaf, nritems + 1);
/* write the data for the start of the original item */
write_extent_buffer(leaf, buf,
btrfs_item_ptr_offset(leaf, path->slots[0]),
split_offset);
/* write the data for the new item */
write_extent_buffer(leaf, buf + split_offset,
btrfs_item_ptr_offset(leaf, slot),
item_size - split_offset);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(leaf) < 0) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
BUG();
}
kfree(buf);
return ret;
}
int btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end)
{
int ret = 0;
int slot;
struct extent_buffer *leaf;
u32 nritems;
unsigned int data_end;
unsigned int old_data_start;
unsigned int old_size;
unsigned int size_diff;
int i;
leaf = path->nodes[0];
slot = path->slots[0];
old_size = btrfs_item_size(leaf, slot);
if (old_size == new_size)
return 0;
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(leaf);
old_data_start = btrfs_item_offset(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;
ioff = btrfs_item_offset(leaf, i);
btrfs_set_item_offset(leaf, i, ioff + size_diff);
}
/* shift the data */
if (from_end) {
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) +
data_end + size_diff, btrfs_item_nr_offset(leaf, 0) +
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_item_nr_offset(leaf, 0) +
data_end + size_diff, btrfs_item_nr_offset(leaf, 0) +
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)
btrfs_fixup_low_keys(path, &disk_key, 1);
}
btrfs_set_item_size(leaf, slot, new_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(leaf) < 0) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
BUG();
}
return ret;
}
int btrfs_extend_item(struct btrfs_root *root, struct btrfs_path *path,
u32 data_size)
{
int ret = 0;
int slot;
struct extent_buffer *leaf;
u32 nritems;
unsigned int data_end;
unsigned int old_data;
unsigned int old_size;
int i;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(leaf);
if (btrfs_leaf_free_space(leaf) < data_size) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
BUG();
}
slot = path->slots[0];
old_data = btrfs_item_data_end(leaf, slot);
BUG_ON(slot < 0);
if (slot >= nritems) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
printk("slot %d too large, nritems %u\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;
ioff = btrfs_item_offset(leaf, i);
btrfs_set_item_offset(leaf, i, ioff - data_size);
}
/* shift the data */
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) +
data_end - data_size, btrfs_item_nr_offset(leaf, 0) +
data_end, old_data - data_end);
data_end = old_data;
old_size = btrfs_item_size(leaf, slot);
btrfs_set_item_size(leaf, slot, old_size + data_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(leaf) < 0) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
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;
int ret = 0;
int slot;
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];
}
/* create a root if there isn't one */
if (!root->node)
BUG();
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;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(leaf);
if (btrfs_leaf_free_space(leaf) < total_size) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
printk("not enough freespace need %u have %d\n",
total_size, btrfs_leaf_free_space(leaf));
BUG();
}
slot = path->slots[0];
BUG_ON(slot < 0);
if (slot < nritems) {
unsigned int old_data = btrfs_item_data_end(leaf, slot);
if (old_data < data_end) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
printk("slot %d old_data %u data_end %u\n",
slot, old_data, data_end);
BUG_ON(1);
}
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
ioff = btrfs_item_offset(leaf, i);
btrfs_set_item_offset(leaf, i, ioff - total_data);
}
/* shift the items */
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, slot + nr),
btrfs_item_nr_offset(leaf, slot),
(nritems - slot) * sizeof(struct btrfs_item));
/* shift the data */
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) +
data_end - total_data, btrfs_item_nr_offset(leaf, 0) +
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);
btrfs_set_item_offset(leaf, slot + i, data_end - data_size[i]);
data_end -= data_size[i];
btrfs_set_item_size(leaf, slot + i, 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);
btrfs_fixup_low_keys(path, &disk_key, 1);
}
if (btrfs_leaf_free_space(leaf) < 0) {
btrfs_print_leaf(leaf, BTRFS_PRINT_TREE_DEFAULT);
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();
if (!path)
return -ENOMEM;
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.
*/
int btrfs_del_ptr(struct btrfs_root *root, struct btrfs_path *path,
int level, int slot)
{
struct extent_buffer *parent = path->nodes[level];
u32 nritems;
int ret = 0;
nritems = btrfs_header_nritems(parent);
if (slot < nritems - 1) {
/* shift the items */
memmove_extent_buffer(parent,
btrfs_node_key_ptr_offset(parent, slot),
btrfs_node_key_ptr_offset(parent, 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);
btrfs_fixup_low_keys(path, &disk_key, level + 1);
}
btrfs_mark_buffer_dirty(parent);
return ret;
}
/*
* a helper function to delete the leaf pointed to by path->slots[1] and
* path->nodes[1].
*
* This deletes the pointer in path->nodes[1] and frees the leaf
* block extent. zero is returned if it all worked out, < 0 otherwise.
*
* The path must have already been setup for deleting the leaf, including
* all the proper balancing. path->nodes[1] must be locked.
*/
static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct extent_buffer *leaf)
{
int ret;
WARN_ON(btrfs_header_generation(leaf) != trans->transid);
ret = btrfs_del_ptr(root, path, 1, path->slots[1]);
if (ret)
return ret;
root_sub_used(root, leaf->len);
ret = btrfs_free_extent(trans, leaf->start, leaf->len, 0,
root->root_key.objectid, 0, 0);
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;
int last_off;
int dsize = 0;
int ret = 0;
int wret;
int i;
u32 nritems;
leaf = path->nodes[0];
last_off = btrfs_item_offset(leaf, slot + nr - 1);
for (i = 0; i < nr; i++)
dsize += btrfs_item_size(leaf, slot + i);
nritems = btrfs_header_nritems(leaf);
if (slot + nr != nritems) {
int data_end = leaf_data_end(leaf);
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) +
data_end + dsize,
btrfs_item_nr_offset(leaf, 0) + data_end,
last_off - data_end);
for (i = slot + nr; i < nritems; i++) {
u32 ioff;
ioff = btrfs_item_offset(leaf, i);
btrfs_set_item_offset(leaf, i, ioff + dsize);
}
memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, slot),
btrfs_item_nr_offset(leaf, 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 {
btrfs_clear_buffer_dirty(leaf);
wret = btrfs_del_leaf(trans, root, path, leaf);
BUG_ON(ret);
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);
btrfs_fixup_low_keys(path, &disk_key, 1);
}
/* delete the leaf if it is mostly empty */
if (used < BTRFS_LEAF_DATA_SIZE(root->fs_info) / 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) {
btrfs_clear_buffer_dirty(leaf);
path->slots[1] = slot;
ret = btrfs_del_leaf(trans, root, path, leaf);
BUG_ON(ret);
free_extent_buffer(leaf);
} else {
btrfs_mark_buffer_dirty(leaf);
free_extent_buffer(leaf);
}
} else {
btrfs_mark_buffer_dirty(leaf);
}
}
return ret;
}
/*
* walk up the tree as far as required to find the previous leaf.
* 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)
{
int slot;
int level = 1;
struct extent_buffer *c;
struct extent_buffer *next = NULL;
struct btrfs_fs_info *fs_info = root->fs_info;
while(level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
return 1;
slot = path->slots[level];
c = path->nodes[level];
if (slot == 0) {
level++;
if (level == BTRFS_MAX_LEVEL)
return 1;
continue;
}
slot--;
next = read_node_slot(fs_info, c, slot);
if (!extent_buffer_uptodate(next)) {
if (IS_ERR(next))
return PTR_ERR(next);
return -EIO;
}
break;
}
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
free_extent_buffer(c);
slot = btrfs_header_nritems(next);
if (slot != 0)
slot--;
path->nodes[level] = next;
path->slots[level] = slot;
if (!level)
break;
next = read_node_slot(fs_info, next, slot);
if (!extent_buffer_uptodate(next)) {
if (IS_ERR(next))
return PTR_ERR(next);
return -EIO;
}
}
return 0;
}
/*
* Walk up the tree as far as necessary to find the next sibling tree block.
* More generic version of btrfs_next_leaf(), as it could find sibling nodes
* if @path->lowest_level is not 0.
*
* returns 0 if it found something or 1 if there are no greater leaves.
* returns < 0 on io errors.
*/
int btrfs_next_sibling_tree_block(struct btrfs_fs_info *fs_info,
struct btrfs_path *path)
{
int slot;
int level = path->lowest_level + 1;
struct extent_buffer *c;
struct extent_buffer *next = NULL;
BUG_ON(path->lowest_level + 1 >= BTRFS_MAX_LEVEL);
do {
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 (path->reada)
reada_for_search(fs_info, path, level, slot, 0);
next = read_node_slot(fs_info, c, slot);
if (!extent_buffer_uptodate(next))
return -EIO;
break;
} while (level < BTRFS_MAX_LEVEL);
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
free_extent_buffer(c);
path->nodes[level] = next;
path->slots[level] = 0;
/*
* Fsck will happily load corrupt blocks in order to fix them,
* so we need an extra check just to make sure this block isn't
* marked uptodate but invalid.
*/
if (check_block(fs_info, path, level))
return -EIO;
if (level == path->lowest_level)
break;
if (path->reada)
reada_for_search(fs_info, path, level, 0, 0);
next = read_node_slot(fs_info, next, 0);
if (!extent_buffer_uptodate(next))
return -EIO;
}
return 0;
}
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;
u32 nritems;
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];
nritems = btrfs_header_nritems(leaf);
if (nritems == 0)
return 1;
if (path->slots[0] == nritems)
path->slots[0]--;
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.objectid < min_objectid)
break;
if (found_key.type == type)
return 0;
if (found_key.objectid == min_objectid &&
found_key.type < type)
break;
}
return 1;
}
/*
* search in extent tree to find a previous Metadata/Data extent item with
* min objectid.
*
* returns 0 if something is found, 1 if nothing was found and < 0 on error
*/
int btrfs_previous_extent_item(struct btrfs_root *root,
struct btrfs_path *path, u64 min_objectid)
{
struct btrfs_key found_key;
struct extent_buffer *leaf;
u32 nritems;
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];
nritems = btrfs_header_nritems(leaf);
if (nritems == 0)
return 1;
if (path->slots[0] == nritems)
path->slots[0]--;
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.objectid < min_objectid)
break;
if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
found_key.type == BTRFS_METADATA_ITEM_KEY)
return 0;
if (found_key.objectid == min_objectid &&
found_key.type < BTRFS_EXTENT_ITEM_KEY)
break;
}
return 1;
}
/*
* Search in extent tree to found next meta/data extent
* Caller needs to check for no-hole or skinny metadata features.
*/
int btrfs_next_extent_item(struct btrfs_root *root,
struct btrfs_path *path, u64 max_objectid)
{
struct btrfs_key found_key;
int ret;
while (1) {
ret = btrfs_next_item(root, path);
if (ret)
return ret;
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (found_key.objectid > max_objectid)
return 1;
if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
found_key.type == BTRFS_METADATA_ITEM_KEY)
return 0;
}
}
/*
* Search uuid tree - unmounted
*
* return -ENOENT for !found, < 0 for errors, or 0 if an item was found
*/
static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid,
u8 type, u64 subid)
{
int ret;
struct btrfs_path *path = NULL;
struct extent_buffer *eb;
int slot;
u32 item_size;
unsigned long offset;
struct btrfs_key key;
if (!uuid_root) {
ret = -ENOENT;
goto out;
}
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
btrfs_uuid_to_key(uuid, &key);
key.type = type;
ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = -ENOENT;
goto out;
}
eb = path->nodes[0];
slot = path->slots[0];
item_size = btrfs_item_size(eb, slot);
offset = btrfs_item_ptr_offset(eb, slot);
ret = -ENOENT;
if (!IS_ALIGNED(item_size, sizeof(u64))) {
warning("uuid item with invalid size %lu!",
(unsigned long)item_size);
goto out;
}
while (item_size) {
__le64 data;
read_extent_buffer(eb, &data, offset, sizeof(data));
if (le64_to_cpu(data) == subid) {
ret = 0;
break;
}
offset += sizeof(data);
item_size -= sizeof(data);
}
out:
btrfs_free_path(path);
return ret;
}
int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
u64 subvol_id_cpu)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *uuid_root = fs_info->uuid_root;
int ret;
struct btrfs_path *path = NULL;
struct btrfs_key key;
struct extent_buffer *eb;
int slot;
unsigned long offset;
__le64 subvol_id_le;
if (!uuid_root) {
warning("%s: uuid root is not initialized", __func__);
return -EINVAL;
}
ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subvol_id_cpu);
if (ret != -ENOENT)
return ret;
key.type = type;
btrfs_uuid_to_key(uuid, &key);
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
sizeof(subvol_id_le));
if (ret < 0 && ret != -EEXIST) {
warning(
"inserting uuid item failed (0x%016llx, 0x%016llx) type %u: %d",
(unsigned long long)key.objectid,
(unsigned long long)key.offset, type, ret);
goto out;
}
if (ret >= 0) {
/* Add an item for the type for the first time */
eb = path->nodes[0];
slot = path->slots[0];
offset = btrfs_item_ptr_offset(eb, slot);
} else {
/*
* ret == -EEXIST case, An item with that type already exists.
* Extend the item and store the new subvol_id at the end.
*/
btrfs_extend_item(uuid_root, path, sizeof(subvol_id_le));
eb = path->nodes[0];
slot = path->slots[0];
offset = btrfs_item_ptr_offset(eb, slot);
offset += btrfs_item_size(eb, slot) - sizeof(subvol_id_le);
}
ret = 0;
subvol_id_le = cpu_to_le64(subvol_id_cpu);
write_extent_buffer(eb, &subvol_id_le, offset, sizeof(subvol_id_le));
btrfs_mark_buffer_dirty(eb);
out:
btrfs_free_path(path);
return ret;
}
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