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btrfs-progs/ctree.c
Josef Bacik 70749a77fe Btrfs-progs: deal with invalid key orderings and bad orphan items V2 
A user had a fs where the objectid of an orphan item was not the actual orphan
item objectid.  This screwed up fsck because the block has keys in the wrong
order, also the fs scanning stuff will freak out because we have an inode with
nlink 0 and no orphan item.  So this patch is pretty big but is all related.

1) Deal with bad key ordering.  We can easily fix this up, so fix the checking
stuff to tell us exactly what it found when it said there was a problem.  Then
if it's bad key ordering we can reorder the keys and restart the scan.

2) Deal with bad keys.  If we find an orphan item with the wrong objectid it's
likely to screw with stuff, so keep track of these sort of things with a
bad_item list and just run through and delete any objects that don't make sense.
So far we just do this for orphan items but we could extend this as new stuff
pops up.

3) Deal with missing orphan items.  This is easy, if we have a file with i_nlink
set to 0 and no orphan item we can just add an orphan item.

4) Add the infrastructure to corrupt actual key values.  Needed this to create a
test image to verify I was fixing things properly.

This patch fixes the corrupt image I'm adding and passes the other make test
tests.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
2014-01-31 08:22:15 -08:00

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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"
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int level);
static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *ins_key,
struct btrfs_path *path, int data_size, int extend);
static int push_node_left(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *dst,
struct extent_buffer *src, int empty);
static int balance_node_right(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *dst_buf,
struct extent_buffer *src_buf);
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)
{
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);
}
}
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->fsid,
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;
}
/*
* 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 refernece 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;
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
if (root->ref_cows &&
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
return 1;
#endif
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, root, 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, root, 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(trans, root, 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->fsid,
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, 1);
}
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)(1024 * 1024 * 1024) - 1);
ret = __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0);
return ret;
}
int btrfs_comp_cpu_keys(struct btrfs_key *k1, 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, 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(struct btrfs_root *root,
struct extent_buffer *leaf)
{
u32 nr = btrfs_header_nritems(leaf);
if (nr == 0)
return BTRFS_LEAF_DATA_SIZE(root);
return btrfs_item_offset_nr(leaf, nr - 1);
}
enum btrfs_tree_block_status
btrfs_check_node(struct btrfs_root *root, 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(root))
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(root->fs_info, &cpukey,
buf->start, buf->len,
btrfs_header_level(buf));
}
return ret;
}
enum btrfs_tree_block_status
btrfs_check_leaf(struct btrfs_root *root, 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(root, 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(root, 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 - 2; 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(root)) {
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(root));
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(root->fs_info, &cpukey,
buf->start, buf->len, 0);
}
return ret;
}
static int noinline check_block(struct btrfs_root *root,
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(root, key_ptr, path->nodes[0]);
else
ret = btrfs_check_node(root, 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, 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
*/
static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
int level, int *slot)
{
if (level == 0)
return generic_bin_search(eb,
offsetof(struct btrfs_leaf, items),
sizeof(struct btrfs_item),
key, btrfs_header_nritems(eb),
slot);
else
return generic_bin_search(eb,
offsetof(struct btrfs_node, ptrs),
sizeof(struct btrfs_key_ptr),
key, btrfs_header_nritems(eb),
slot);
}
struct extent_buffer *read_node_slot(struct btrfs_root *root,
struct extent_buffer *parent, int slot)
{
int level = btrfs_header_level(parent);
if (slot < 0)
return NULL;
if (slot >= btrfs_header_nritems(parent))
return NULL;
if (level == 0)
return NULL;
return read_tree_block(root, btrfs_node_blockptr(parent, slot),
btrfs_level_size(root, level - 1),
btrfs_node_ptr_generation(parent, slot));
}
static int balance_level(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
struct extent_buffer *right = NULL;
struct extent_buffer *mid;
struct extent_buffer *left = NULL;
struct extent_buffer *parent = NULL;
int ret = 0;
int wret;
int pslot;
int orig_slot = path->slots[level];
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(root, mid, 0);
BUG_ON(!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(trans, root, mid);
wait_on_tree_block_writeback(root, mid);
/* once for the path */
free_extent_buffer(mid);
ret = btrfs_free_extent(trans, root, mid->start, mid->len,
0, root->root_key.objectid,
level, 1);
/* once for the root ptr */
free_extent_buffer(mid);
return ret;
}
if (btrfs_header_nritems(mid) >
BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
return 0;
left = read_node_slot(root, parent, pslot - 1);
if (left) {
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left);
if (wret) {
ret = wret;
goto enospc;
}
}
right = read_node_slot(root, parent, pslot + 1);
if (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(trans, root, right);
wait_on_tree_block_writeback(root, right);
free_extent_buffer(right);
right = NULL;
wret = btrfs_del_ptr(trans, root, path,
level + 1, pslot + 1);
if (wret)
ret = wret;
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(trans, root, mid);
wait_on_tree_block_writeback(root, mid);
free_extent_buffer(mid);
mid = NULL;
wret = btrfs_del_ptr(trans, root, path, level + 1, pslot);
if (wret)
ret = wret;
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);
} else {
orig_slot -= btrfs_header_nritems(left);
path->slots[level] = orig_slot;
}
}
/* double check we haven't messed things up */
check_block(root, path, level);
if (orig_ptr !=
btrfs_node_blockptr(path->nodes[level], path->slots[level]))
BUG();
enospc:
if (right)
free_extent_buffer(right);
if (left)
free_extent_buffer(left);
return ret;
}
/* returns zero if the push worked, non-zero otherwise */
static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
struct extent_buffer *right = NULL;
struct extent_buffer *mid;
struct extent_buffer *left = NULL;
struct extent_buffer *parent = NULL;
int ret = 0;
int wret;
int pslot;
int orig_slot = path->slots[level];
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(root, parent, pslot - 1);
/* first, try to make some room in the middle buffer */
if (left) {
u32 left_nr;
left_nr = btrfs_header_nritems(left);
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, left, parent,
pslot - 1, &left);
if (ret)
wret = 1;
else {
wret = push_node_left(trans, root,
left, mid, 0);
}
}
if (wret < 0)
ret = wret;
if (wret == 0) {
struct btrfs_disk_key disk_key;
orig_slot += left_nr;
btrfs_node_key(mid, &disk_key, 0);
btrfs_set_node_key(parent, &disk_key, pslot);
btrfs_mark_buffer_dirty(parent);
if (btrfs_header_nritems(left) > orig_slot) {
path->nodes[level] = left;
path->slots[level + 1] -= 1;
path->slots[level] = orig_slot;
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(root, parent, pslot + 1);
/*
* then try to empty the right most buffer into the middle
*/
if (right) {
u32 right_nr;
right_nr = btrfs_header_nritems(right);
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, right,
parent, pslot + 1,
&right);
if (ret)
wret = 1;
else {
wret = balance_node_right(trans, root,
right, mid);
}
}
if (wret < 0)
ret = wret;
if (wret == 0) {
struct btrfs_disk_key disk_key;
btrfs_node_key(right, &disk_key, 0);
btrfs_set_node_key(parent, &disk_key, pslot + 1);
btrfs_mark_buffer_dirty(parent);
if (btrfs_header_nritems(mid) <= orig_slot) {
path->nodes[level] = right;
path->slots[level + 1] += 1;
path->slots[level] = orig_slot -
btrfs_header_nritems(mid);
free_extent_buffer(mid);
} else {
free_extent_buffer(right);
}
return 0;
}
free_extent_buffer(right);
}
return 1;
}
/*
* readahead one full node of leaves
*/
void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
int level, int slot, u64 objectid)
{
struct extent_buffer *node;
struct btrfs_disk_key disk_key;
u32 nritems;
u64 search;
u64 lowest_read;
u64 highest_read;
u64 nread = 0;
int direction = path->reada;
struct extent_buffer *eb;
u32 nr;
u32 blocksize;
u32 nscan = 0;
if (level != 1)
return;
if (!path->nodes[level])
return;
node = path->nodes[level];
search = btrfs_node_blockptr(node, slot);
blocksize = btrfs_level_size(root, level - 1);
eb = btrfs_find_tree_block(root, search, blocksize);
if (eb) {
free_extent_buffer(eb);
return;
}
highest_read = search;
lowest_read = search;
nritems = btrfs_header_nritems(node);
nr = slot;
while(1) {
if (direction < 0) {
if (nr == 0)
break;
nr--;
} else if (direction > 0) {
nr++;
if (nr >= nritems)
break;
}
if (path->reada < 0 && objectid) {
btrfs_node_key(node, &disk_key, nr);
if (btrfs_disk_key_objectid(&disk_key) != objectid)
break;
}
search = btrfs_node_blockptr(node, nr);
if ((search >= lowest_read && search <= highest_read) ||
(search < lowest_read && lowest_read - search <= 32768) ||
(search > highest_read && search - highest_read <= 32768)) {
readahead_tree_block(root, search, blocksize,
btrfs_node_ptr_generation(node, nr));
nread += blocksize;
}
nscan++;
if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
break;
if(nread > (1024 * 1024) || nscan > 128)
break;
if (search < lowest_read)
lowest_read = search;
if (search > highest_read)
highest_read = search;
}
}
/*
* look for key in the tree. path is filled in with nodes along the way
* if key is found, we return zero and you can find the item in the leaf
* level of the path (level 0)
*
* If the key isn't found, the path points to the slot where it should
* be inserted, and 1 is returned. If there are other errors during the
* search a negative error number is returned.
*
* if ins_len > 0, nodes and leaves will be split as we walk down the
* tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
* possible)
*/
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *key, struct btrfs_path *p, int
ins_len, int cow)
{
struct extent_buffer *b;
int slot;
int ret;
int level;
int should_reada = p->reada;
u8 lowest_level = 0;
lowest_level = p->lowest_level;
WARN_ON(lowest_level && ins_len > 0);
WARN_ON(p->nodes[0] != NULL);
/*
WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
*/
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(root, p, level);
if (ret)
return -1;
ret = bin_search(b, key, level, &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(root) - 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(root, p, level, slot,
key->objectid);
b = read_node_slot(root, b, slot);
if (!extent_buffer_uptodate(b))
return -EIO;
} else {
p->slots[level] = slot;
if (ins_len > 0 &&
ins_len > btrfs_leaf_free_space(root, 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;
}
/*
* 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_root *root, 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(root, 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(root, 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 btrfs_root *root, struct extent_buffer *dst,
struct extent_buffer *src, int empty)
{
int push_items = 0;
int src_nritems;
int dst_nritems;
int ret = 0;
src_nritems = btrfs_header_nritems(src);
dst_nritems = btrfs_header_nritems(dst);
push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
WARN_ON(btrfs_header_generation(src) != trans->transid);
WARN_ON(btrfs_header_generation(dst) != trans->transid);
if (!empty && src_nritems <= 8)
return 1;
if (push_items <= 0) {
return 1;
}
if (empty) {
push_items = min(src_nritems, push_items);
if (push_items < src_nritems) {
/* leave at least 8 pointers in the node if
* we aren't going to empty it
*/
if (src_nritems - push_items < 8) {
if (push_items <= 8)
return 1;
push_items -= 8;
}
}
} else
push_items = min(src_nritems - 8, push_items);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(dst_nritems),
btrfs_node_key_ptr_offset(0),
push_items * sizeof(struct btrfs_key_ptr));
if (push_items < src_nritems) {
memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(push_items),
(src_nritems - push_items) *
sizeof(struct btrfs_key_ptr));
}
btrfs_set_header_nritems(src, src_nritems - push_items);
btrfs_set_header_nritems(dst, dst_nritems + push_items);
btrfs_mark_buffer_dirty(src);
btrfs_mark_buffer_dirty(dst);
return ret;
}
/*
* try to push data from one node into the next node right in the
* tree.
*
* returns 0 if some ptrs were pushed, < 0 if there was some horrible
* error, and > 0 if there was no room in the right hand block.
*
* this will only push up to 1/2 the contents of the left node over
*/
static int balance_node_right(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *dst,
struct extent_buffer *src)
{
int push_items = 0;
int max_push;
int src_nritems;
int dst_nritems;
int ret = 0;
WARN_ON(btrfs_header_generation(src) != trans->transid);
WARN_ON(btrfs_header_generation(dst) != trans->transid);
src_nritems = btrfs_header_nritems(src);
dst_nritems = btrfs_header_nritems(dst);
push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
if (push_items <= 0) {
return 1;
}
if (src_nritems < 4) {
return 1;
}
max_push = src_nritems / 2 + 1;
/* don't try to empty the node */
if (max_push >= src_nritems) {
return 1;
}
if (max_push < push_items)
push_items = max_push;
memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
btrfs_node_key_ptr_offset(0),
(dst_nritems) *
sizeof(struct btrfs_key_ptr));
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(src_nritems - push_items),
push_items * sizeof(struct btrfs_key_ptr));
btrfs_set_header_nritems(src, src_nritems - push_items);
btrfs_set_header_nritems(dst, dst_nritems + push_items);
btrfs_mark_buffer_dirty(src);
btrfs_mark_buffer_dirty(dst);
return ret;
}
/*
* helper function to insert a new root level in the tree.
* A new node is allocated, and a single item is inserted to
* point to the existing root
*
* returns zero on success or < 0 on failure.
*/
static int noinline insert_new_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
u64 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_free_block(trans, root, root->nodesize,
root->root_key.objectid, &lower_key,
level, root->node->start, 0);
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);
write_extent_buffer(c, root->fs_info->fsid,
btrfs_header_fsid(), BTRFS_FSID_SIZE);
write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
btrfs_header_chunk_tree_uuid(c),
BTRFS_UUID_SIZE);
btrfs_set_node_key(c, &lower_key, 0);
btrfs_set_node_blockptr(c, 0, lower->start);
lower_gen = btrfs_header_generation(lower);
WARN_ON(lower_gen != 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))
BUG();
if (slot != nritems) {
memmove_extent_buffer(lower,
btrfs_node_key_ptr_offset(slot + 1),
btrfs_node_key_ptr_offset(slot),
(nritems - slot) * sizeof(struct btrfs_key_ptr));
}
btrfs_set_node_key(lower, key, slot);
btrfs_set_node_blockptr(lower, slot, bytenr);
WARN_ON(trans->transid == 0);
btrfs_set_node_ptr_generation(lower, slot, trans->transid);
btrfs_set_header_nritems(lower, nritems + 1);
btrfs_mark_buffer_dirty(lower);
return 0;
}
/*
* split the node at the specified level in path in two.
* The path is corrected to point to the appropriate node after the split
*
* Before splitting this tries to make some room in the node by pushing
* left and right, if either one works, it returns right away.
*
* returns 0 on success and < 0 on failure
*/
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int level)
{
struct extent_buffer *c;
struct extent_buffer *split;
struct btrfs_disk_key disk_key;
int mid;
int ret;
int wret;
u32 c_nritems;
c = path->nodes[level];
WARN_ON(btrfs_header_generation(c) != trans->transid);
if (c == root->node) {
/* trying to split the root, lets make a new one */
ret = insert_new_root(trans, root, path, level + 1);
if (ret)
return ret;
} else {
ret = push_nodes_for_insert(trans, root, path, level);
c = path->nodes[level];
if (!ret && btrfs_header_nritems(c) <
BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
return 0;
if (ret < 0)
return ret;
}
c_nritems = btrfs_header_nritems(c);
mid = (c_nritems + 1) / 2;
btrfs_node_key(c, &disk_key, mid);
split = btrfs_alloc_free_block(trans, root, root->nodesize,
root->root_key.objectid,
&disk_key, level, c->start, 0);
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(split, root->fs_info->fsid,
btrfs_header_fsid(), BTRFS_FSID_SIZE);
write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
btrfs_header_chunk_tree_uuid(split),
BTRFS_UUID_SIZE);
copy_extent_buffer(split, c,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(mid),
(c_nritems - mid) * sizeof(struct btrfs_key_ptr));
btrfs_set_header_nritems(split, c_nritems - mid);
btrfs_set_header_nritems(c, mid);
ret = 0;
btrfs_mark_buffer_dirty(c);
btrfs_mark_buffer_dirty(split);
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_end_nr(l, start);
data_len = data_len - btrfs_item_offset_nr(l, end);
data_len += sizeof(struct btrfs_item) * nr;
WARN_ON(data_len < 0);
return data_len;
}
/*
* The space between the end of the leaf items and
* the start of the leaf data. IOW, how much room
* the leaf has left for both items and data
*/
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
{
int nritems = btrfs_header_nritems(leaf);
int ret;
ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
if (ret < 0) {
printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
leaf_space_used(leaf, 0, nritems), nritems);
}
return ret;
}
/*
* push some data in the path leaf to the right, trying to free up at
* least data_size bytes. returns zero if the push worked, nonzero otherwise
*
* returns 1 if the push failed because the other node didn't have enough
* room, 0 if everything worked out and < 0 if there were major errors.
*/
static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int data_size,
int empty)
{
struct extent_buffer *left = path->nodes[0];
struct extent_buffer *right;
struct extent_buffer *upper;
struct btrfs_disk_key disk_key;
int slot;
u32 i;
int free_space;
int push_space = 0;
int push_items = 0;
struct btrfs_item *item;
u32 left_nritems;
u32 nr;
u32 right_nritems;
u32 data_end;
u32 this_item_size;
int ret;
slot = path->slots[1];
if (!path->nodes[1]) {
return 1;
}
upper = path->nodes[1];
if (slot >= btrfs_header_nritems(upper) - 1)
return 1;
right = read_node_slot(root, upper, slot + 1);
free_space = btrfs_leaf_free_space(root, 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(root, 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) {
item = btrfs_item_nr(i);
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
this_item_size = btrfs_item_size(left, item);
if (this_item_size + sizeof(*item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(*item);
if (i == 0)
break;
i--;
}
if (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_end_nr(left, left_nritems - push_items);
push_space -= leaf_data_end(root, left);
/* make room in the right data area */
data_end = leaf_data_end(root, right);
memmove_extent_buffer(right,
btrfs_leaf_data(right) + data_end - push_space,
btrfs_leaf_data(right) + data_end,
BTRFS_LEAF_DATA_SIZE(root) - data_end);
/* copy from the left data area */
copy_extent_buffer(right, left, btrfs_leaf_data(right) +
BTRFS_LEAF_DATA_SIZE(root) - push_space,
btrfs_leaf_data(left) + leaf_data_end(root, left),
push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
btrfs_item_nr_offset(0),
right_nritems * sizeof(struct btrfs_item));
/* copy the items from left to right */
copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(left_nritems - push_items),
push_items * sizeof(struct btrfs_item));
/* update the item pointers */
right_nritems += push_items;
btrfs_set_header_nritems(right, right_nritems);
push_space = BTRFS_LEAF_DATA_SIZE(root);
for (i = 0; i < right_nritems; i++) {
item = btrfs_item_nr(i);
push_space -= btrfs_item_size(right, item);
btrfs_set_item_offset(right, item, 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;
int slot;
int i;
int free_space;
int push_space = 0;
int push_items = 0;
struct btrfs_item *item;
u32 old_left_nritems;
u32 right_nritems;
u32 nr;
int ret = 0;
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(root, path->nodes[1], slot - 1);
free_space = btrfs_leaf_free_space(root, 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(root, 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++) {
item = btrfs_item_nr(i);
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
this_item_size = btrfs_item_size(right, item);
if (this_item_size + sizeof(*item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(*item);
}
if (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(btrfs_header_nritems(left)),
btrfs_item_nr_offset(0),
push_items * sizeof(struct btrfs_item));
push_space = BTRFS_LEAF_DATA_SIZE(root) -
btrfs_item_offset_nr(right, push_items -1);
copy_extent_buffer(left, right, btrfs_leaf_data(left) +
leaf_data_end(root, left) - push_space,
btrfs_leaf_data(right) +
btrfs_item_offset_nr(right, push_items - 1),
push_space);
old_left_nritems = btrfs_header_nritems(left);
BUG_ON(old_left_nritems == 0);
old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
u32 ioff;
item = btrfs_item_nr(i);
ioff = btrfs_item_offset(left, item);
btrfs_set_item_offset(left, item,
ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
}
btrfs_set_header_nritems(left, old_left_nritems + push_items);
/* fixup right node */
if (push_items > right_nritems) {
printk("push items %d nr %u\n", push_items, right_nritems);
WARN_ON(1);
}
if (push_items < right_nritems) {
push_space = btrfs_item_offset_nr(right, push_items - 1) -
leaf_data_end(root, right);
memmove_extent_buffer(right, btrfs_leaf_data(right) +
BTRFS_LEAF_DATA_SIZE(root) - push_space,
btrfs_leaf_data(right) +
leaf_data_end(root, right), push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(push_items),
(btrfs_header_nritems(right) - push_items) *
sizeof(struct btrfs_item));
}
right_nritems -= push_items;
btrfs_set_header_nritems(right, right_nritems);
push_space = BTRFS_LEAF_DATA_SIZE(root);
for (i = 0; i < right_nritems; i++) {
item = btrfs_item_nr(i);
push_space = push_space - btrfs_item_size(right, item);
btrfs_set_item_offset(right, item, 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(root, 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_end_nr(l, mid) - leaf_data_end(root, l);
copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(mid),
nritems * sizeof(struct btrfs_item));
copy_extent_buffer(right, l,
btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
data_copy_size, btrfs_leaf_data(l) +
leaf_data_end(root, l), data_copy_size);
rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
btrfs_item_end_nr(l, mid);
for (i = 0; i < nritems; i++) {
struct btrfs_item *item = btrfs_item_nr(i);
u32 ioff = btrfs_item_offset(right, item);
btrfs_set_item_offset(right, item, 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,
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;
/* 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(root, 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)) {
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)) {
split = 2;
}
}
}
} else {
if (leaf_space_used(l, 0, mid) + data_size >
BTRFS_LEAF_DATA_SIZE(root)) {
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)) {
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_free_block(trans, root, root->leafsize,
root->root_key.objectid,
&disk_key, 0, l->start, 0);
if (IS_ERR(right)) {
BUG_ON(1);
return PTR_ERR(right);
}
memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
btrfs_set_header_bytenr(right, right->start);
btrfs_set_header_generation(right, trans->transid);
btrfs_set_header_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(right, root->fs_info->fsid,
btrfs_header_fsid(), BTRFS_FSID_SIZE);
write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
btrfs_header_chunk_tree_uuid(right),
BTRFS_UUID_SIZE);
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(root, 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;
struct btrfs_item *item;
struct btrfs_item *new_item;
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(root, leaf) >= sizeof(struct btrfs_item))
goto split;
item_size = btrfs_item_size_nr(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_nr(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(root, leaf) < sizeof(struct btrfs_item));
leaf = path->nodes[0];
split:
item = btrfs_item_nr(path->slots[0]);
orig_offset = btrfs_item_offset(leaf, item);
item_size = btrfs_item_size(leaf, item);
buf = kmalloc(item_size, GFP_NOFS);
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(slot + 1),
btrfs_item_nr_offset(slot),
(nritems - slot) * sizeof(struct btrfs_item));
}
btrfs_cpu_key_to_disk(&disk_key, new_key);
btrfs_set_item_key(leaf, &disk_key, slot);
new_item = btrfs_item_nr(slot);
btrfs_set_item_offset(leaf, new_item, orig_offset);
btrfs_set_item_size(leaf, new_item, item_size - split_offset);
btrfs_set_item_offset(leaf, item,
orig_offset + item_size - split_offset);
btrfs_set_item_size(leaf, item, 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(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
kfree(buf);
return ret;
}
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u32 new_size, int from_end)
{
int ret = 0;
int slot;
struct extent_buffer *leaf;
struct btrfs_item *item;
u32 nritems;
unsigned int data_end;
unsigned int old_data_start;
unsigned int old_size;
unsigned int size_diff;
int i;
leaf = path->nodes[0];
slot = path->slots[0];
old_size = btrfs_item_size_nr(leaf, slot);
if (old_size == new_size)
return 0;
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(root, leaf);
old_data_start = btrfs_item_offset_nr(leaf, slot);
size_diff = old_size - new_size;
BUG_ON(slot < 0);
BUG_ON(slot >= nritems);
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(i);
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff + size_diff);
}
/* shift the data */
if (from_end) {
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + size_diff, btrfs_leaf_data(leaf) +
data_end, old_data_start + new_size - data_end);
} else {
struct btrfs_disk_key disk_key;
u64 offset;
btrfs_item_key(leaf, &disk_key, slot);
if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
unsigned long ptr;
struct btrfs_file_extent_item *fi;
fi = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
fi = (struct btrfs_file_extent_item *)(
(unsigned long)fi - size_diff);
if (btrfs_file_extent_type(leaf, fi) ==
BTRFS_FILE_EXTENT_INLINE) {
ptr = btrfs_item_ptr_offset(leaf, slot);
memmove_extent_buffer(leaf, ptr,
(unsigned long)fi,
offsetof(struct btrfs_file_extent_item,
disk_bytenr));
}
}
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + size_diff, btrfs_leaf_data(leaf) +
data_end, old_data_start - data_end);
offset = btrfs_disk_key_offset(&disk_key);
btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
btrfs_set_item_key(leaf, &disk_key, slot);
if (slot == 0)
btrfs_fixup_low_keys(root, path, &disk_key, 1);
}
item = btrfs_item_nr(slot);
btrfs_set_item_size(leaf, item, new_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
return ret;
}
int btrfs_extend_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
u32 data_size)
{
int ret = 0;
int slot;
struct extent_buffer *leaf;
struct btrfs_item *item;
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(root, leaf);
if (btrfs_leaf_free_space(root, leaf) < data_size) {
btrfs_print_leaf(root, leaf);
BUG();
}
slot = path->slots[0];
old_data = btrfs_item_end_nr(leaf, slot);
BUG_ON(slot < 0);
if (slot >= nritems) {
btrfs_print_leaf(root, leaf);
printk("slot %d too large, nritems %d\n", slot, nritems);
BUG_ON(1);
}
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(i);
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff - data_size);
}
/* shift the data */
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end - data_size, btrfs_leaf_data(leaf) +
data_end, old_data - data_end);
data_end = old_data;
old_size = btrfs_item_size_nr(leaf, slot);
item = btrfs_item_nr(slot);
btrfs_set_item_size(leaf, item, old_size + data_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
return ret;
}
/*
* Given a key and some data, insert an item into the tree.
* This does all the path init required, making room in the tree if needed.
*/
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *cpu_key, u32 *data_size,
int nr)
{
struct extent_buffer *leaf;
struct btrfs_item *item;
int ret = 0;
int slot;
int 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(root, leaf);
if (btrfs_leaf_free_space(root, leaf) < total_size) {
btrfs_print_leaf(root, leaf);
printk("not enough freespace need %u have %d\n",
total_size, btrfs_leaf_free_space(root, leaf));
BUG();
}
slot = path->slots[0];
BUG_ON(slot < 0);
if (slot != nritems) {
unsigned int old_data = btrfs_item_end_nr(leaf, slot);
if (old_data < data_end) {
btrfs_print_leaf(root, leaf);
printk("slot %d old_data %d data_end %d\n",
slot, old_data, data_end);
BUG_ON(1);
}
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(i);
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff - total_data);
}
/* shift the items */
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
btrfs_item_nr_offset(slot),
(nritems - slot) * sizeof(struct btrfs_item));
/* shift the data */
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end - total_data, btrfs_leaf_data(leaf) +
data_end, old_data - data_end);
data_end = old_data;
}
/* setup the item for the new data */
for (i = 0; i < nr; i++) {
btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
btrfs_set_item_key(leaf, &disk_key, slot + i);
item = btrfs_item_nr(slot + i);
btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
data_end -= data_size[i];
btrfs_set_item_size(leaf, item, data_size[i]);
}
btrfs_set_header_nritems(leaf, nritems + nr);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (slot == 0) {
btrfs_cpu_key_to_disk(&disk_key, cpu_key);
btrfs_fixup_low_keys(root, path, &disk_key, 1);
}
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
out:
return ret;
}
/*
* Given a key and some data, insert an item into the tree.
* This does all the path init required, making room in the tree if needed.
*/
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *cpu_key, void *data, u32
data_size)
{
int ret = 0;
struct btrfs_path *path;
struct extent_buffer *leaf;
unsigned long ptr;
path = btrfs_alloc_path();
BUG_ON(!path);
ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
if (!ret) {
leaf = path->nodes[0];
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, data, ptr, data_size);
btrfs_mark_buffer_dirty(leaf);
}
btrfs_free_path(path);
return ret;
}
/*
* delete the pointer from a given node.
*
* If the delete empties a node, the node is removed from the tree,
* continuing all the way the root if required. The root is converted into
* a leaf if all the nodes are emptied.
*/
int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot)
{
struct extent_buffer *parent = path->nodes[level];
u32 nritems;
int ret = 0;
nritems = btrfs_header_nritems(parent);
if (slot != nritems -1) {
memmove_extent_buffer(parent,
btrfs_node_key_ptr_offset(slot),
btrfs_node_key_ptr_offset(slot + 1),
sizeof(struct btrfs_key_ptr) *
(nritems - slot - 1));
}
nritems--;
btrfs_set_header_nritems(parent, nritems);
if (nritems == 0 && parent == root->node) {
BUG_ON(btrfs_header_level(root->node) != 1);
/* just turn the root into a leaf and break */
btrfs_set_header_level(root->node, 0);
} else if (slot == 0) {
struct btrfs_disk_key disk_key;
btrfs_node_key(parent, &disk_key, 0);
btrfs_fixup_low_keys(root, 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(trans, root, path, 1, path->slots[1]);
if (ret)
return ret;
ret = btrfs_free_extent(trans, root, 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;
struct btrfs_item *item;
int last_off;
int dsize = 0;
int ret = 0;
int wret;
int i;
u32 nritems;
leaf = path->nodes[0];
last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
for (i = 0; i < nr; i++)
dsize += btrfs_item_size_nr(leaf, slot + i);
nritems = btrfs_header_nritems(leaf);
if (slot + nr != nritems) {
int data_end = leaf_data_end(root, leaf);
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + dsize,
btrfs_leaf_data(leaf) + data_end,
last_off - data_end);
for (i = slot + nr; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(i);
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff + dsize);
}
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
btrfs_item_nr_offset(slot + nr),
sizeof(struct btrfs_item) *
(nritems - slot - nr));
}
btrfs_set_header_nritems(leaf, nritems - nr);
nritems -= nr;
/* delete the leaf if we've emptied it */
if (nritems == 0) {
if (leaf == root->node) {
btrfs_set_header_level(leaf, 0);
} else {
clean_tree_block(trans, root, leaf);
wait_on_tree_block_writeback(root, 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(root, path, &disk_key, 1);
}
/* delete the leaf if it is mostly empty */
if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
/* push_leaf_left fixes the path.
* make sure the path still points to our leaf
* for possible call to del_ptr below
*/
slot = path->slots[1];
extent_buffer_get(leaf);
wret = push_leaf_left(trans, root, path, 1, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
if (path->nodes[0] == leaf &&
btrfs_header_nritems(leaf)) {
wret = push_leaf_right(trans, root, path, 1, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
}
if (btrfs_header_nritems(leaf) == 0) {
clean_tree_block(trans, root, leaf);
wait_on_tree_block_writeback(root, 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;
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(root, c, slot);
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(root, next, slot);
}
return 0;
}
/*
* walk up the tree as far as required to find the next leaf.
* returns 0 if it found something or 1 if there are no greater leaves.
* returns < 0 on io errors.
*/
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
int slot;
int level = 1;
struct extent_buffer *c;
struct extent_buffer *next = NULL;
while(level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
return 1;
slot = path->slots[level] + 1;
c = path->nodes[level];
if (slot >= btrfs_header_nritems(c)) {
level++;
if (level == BTRFS_MAX_LEVEL)
return 1;
continue;
}
if (path->reada)
reada_for_search(root, path, level, slot, 0);
next = read_node_slot(root, c, slot);
if (!next)
return -EIO;
break;
}
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
free_extent_buffer(c);
path->nodes[level] = next;
path->slots[level] = 0;
if (!level)
break;
if (path->reada)
reada_for_search(root, path, level, 0, 0);
next = read_node_slot(root, next, 0);
if (!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;
int ret;
while(1) {
if (path->slots[0] == 0) {
ret = btrfs_prev_leaf(root, path);
if (ret != 0)
return ret;
} else {
path->slots[0]--;
}
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.type == type)
return 0;
}
return 1;
}
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