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linux/fs/btrfs/ctree.c
Josef Bacik 2517920135 Btrfs: nuke fs wide allocation mutex V2 
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.

There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.

The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same.  Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.

Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one.  I have tested this heavily and it does
not appear to break anything.  This has to be applied on top of my
find_free_extent redo patch.

I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out.  Thank you,

Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 14:49:05 -04:00

3717 lines
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/*
* Copyright (C) 2007,2008 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/sched.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#include "locking.h"
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int level);
static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *ins_key,
struct btrfs_path *path, int data_size, int extend);
static int push_node_left(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *dst,
struct extent_buffer *src, int empty);
static int balance_node_right(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *dst_buf,
struct extent_buffer *src_buf);
static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot);
inline void btrfs_init_path(struct btrfs_path *p)
{
memset(p, 0, sizeof(*p));
}
struct btrfs_path *btrfs_alloc_path(void)
{
struct btrfs_path *path;
path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
if (path) {
btrfs_init_path(path);
path->reada = 1;
}
return path;
}
/* this also releases the path */
void btrfs_free_path(struct btrfs_path *p)
{
btrfs_release_path(NULL, p);
kmem_cache_free(btrfs_path_cachep, 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.
*/
void noinline btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
{
int i;
for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
p->slots[i] = 0;
if (!p->nodes[i])
continue;
if (p->locks[i]) {
btrfs_tree_unlock(p->nodes[i]);
p->locks[i] = 0;
}
free_extent_buffer(p->nodes[i]);
p->nodes[i] = NULL;
}
}
/*
* safely gets a reference on the root node of a tree. A lock
* is not taken, so a concurrent writer may put a different node
* at the root of the tree. See btrfs_lock_root_node for the
* looping required.
*
* The extent buffer returned by this has a reference taken, so
* it won't disappear. It may stop being the root of the tree
* at any time because there are no locks held.
*/
struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
{
struct extent_buffer *eb;
spin_lock(&root->node_lock);
eb = root->node;
extent_buffer_get(eb);
spin_unlock(&root->node_lock);
return eb;
}
/* loop around taking references on and locking the root node of the
* tree until you end up with a lock on the root. A locked buffer
* is returned, with a reference held.
*/
struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
{
struct extent_buffer *eb;
while(1) {
eb = btrfs_root_node(root);
btrfs_tree_lock(eb);
spin_lock(&root->node_lock);
if (eb == root->node) {
spin_unlock(&root->node_lock);
break;
}
spin_unlock(&root->node_lock);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
}
return eb;
}
/* cowonly root (everything not a reference counted cow subvolume), just get
* put onto a simple dirty list. transaction.c walks this to make sure they
* get properly updated on disk.
*/
static void add_root_to_dirty_list(struct btrfs_root *root)
{
if (root->track_dirty && list_empty(&root->dirty_list)) {
list_add(&root->dirty_list,
&root->fs_info->dirty_cowonly_roots);
}
}
/*
* used by snapshot creation to make a copy of a root for a tree with
* a given objectid. The buffer with the new root node is returned in
* cow_ret, and this func returns zero on success or a negative error code.
*/
int btrfs_copy_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer **cow_ret, u64 new_root_objectid)
{
struct extent_buffer *cow;
u32 nritems;
int ret = 0;
int level;
struct btrfs_root *new_root;
new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
if (!new_root)
return -ENOMEM;
memcpy(new_root, root, sizeof(*new_root));
new_root->root_key.objectid = new_root_objectid;
WARN_ON(root->ref_cows && trans->transid !=
root->fs_info->running_transaction->transid);
WARN_ON(root->ref_cows && trans->transid != root->last_trans);
level = btrfs_header_level(buf);
nritems = btrfs_header_nritems(buf);
cow = btrfs_alloc_free_block(trans, new_root, buf->len, 0,
new_root_objectid, trans->transid,
level, buf->start, 0);
if (IS_ERR(cow)) {
kfree(new_root);
return PTR_ERR(cow);
}
copy_extent_buffer(cow, buf, 0, 0, cow->len);
btrfs_set_header_bytenr(cow, cow->start);
btrfs_set_header_generation(cow, trans->transid);
btrfs_set_header_owner(cow, new_root_objectid);
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
WARN_ON(btrfs_header_generation(buf) > trans->transid);
ret = btrfs_inc_ref(trans, new_root, buf, cow, NULL);
kfree(new_root);
if (ret)
return ret;
btrfs_mark_buffer_dirty(cow);
*cow_ret = cow;
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.
*
* prealloc_dest -- if you have already reserved a destination for the cow,
* this uses that block instead of allocating a new one. btrfs_alloc_reserved_extent
* is used to finish the allocation.
*/
int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret,
u64 search_start, u64 empty_size,
u64 prealloc_dest)
{
u64 parent_start;
struct extent_buffer *cow;
u32 nritems;
int ret = 0;
int level;
int unlock_orig = 0;
if (*cow_ret == buf)
unlock_orig = 1;
WARN_ON(!btrfs_tree_locked(buf));
if (parent)
parent_start = parent->start;
else
parent_start = 0;
WARN_ON(root->ref_cows && trans->transid !=
root->fs_info->running_transaction->transid);
WARN_ON(root->ref_cows && trans->transid != root->last_trans);
level = btrfs_header_level(buf);
nritems = btrfs_header_nritems(buf);
if (prealloc_dest) {
struct btrfs_key ins;
ins.objectid = prealloc_dest;
ins.offset = buf->len;
ins.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_alloc_reserved_extent(trans, root, parent_start,
root->root_key.objectid,
trans->transid, level, &ins);
BUG_ON(ret);
cow = btrfs_init_new_buffer(trans, root, prealloc_dest,
buf->len);
} else {
cow = btrfs_alloc_free_block(trans, root, buf->len,
parent_start,
root->root_key.objectid,
trans->transid, level,
search_start, empty_size);
}
if (IS_ERR(cow))
return PTR_ERR(cow);
copy_extent_buffer(cow, buf, 0, 0, cow->len);
btrfs_set_header_bytenr(cow, cow->start);
btrfs_set_header_generation(cow, trans->transid);
btrfs_set_header_owner(cow, root->root_key.objectid);
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
WARN_ON(btrfs_header_generation(buf) > trans->transid);
if (btrfs_header_generation(buf) != trans->transid) {
u32 nr_extents;
ret = btrfs_inc_ref(trans, root, buf, cow, &nr_extents);
if (ret)
return ret;
ret = btrfs_cache_ref(trans, root, buf, nr_extents);
WARN_ON(ret);
} else if (btrfs_header_owner(buf) == BTRFS_TREE_RELOC_OBJECTID) {
/*
* There are only two places that can drop reference to
* tree blocks owned by living reloc trees, one is here,
* the other place is btrfs_drop_subtree. In both places,
* we check reference count while tree block is locked.
* Furthermore, if reference count is one, it won't get
* increased by someone else.
*/
u32 refs;
ret = btrfs_lookup_extent_ref(trans, root, buf->start,
buf->len, &refs);
BUG_ON(ret);
if (refs == 1) {
ret = btrfs_update_ref(trans, root, buf, cow,
0, nritems);
clean_tree_block(trans, root, buf);
} else {
ret = btrfs_inc_ref(trans, root, buf, cow, NULL);
}
BUG_ON(ret);
} else {
ret = btrfs_update_ref(trans, root, buf, cow, 0, nritems);
if (ret)
return ret;
clean_tree_block(trans, root, buf);
}
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
ret = btrfs_reloc_tree_cache_ref(trans, root, cow, buf->start);
WARN_ON(ret);
}
if (buf == root->node) {
WARN_ON(parent && parent != buf);
spin_lock(&root->node_lock);
root->node = cow;
extent_buffer_get(cow);
spin_unlock(&root->node_lock);
if (buf != root->commit_root) {
btrfs_free_extent(trans, root, buf->start,
buf->len, buf->start,
root->root_key.objectid,
btrfs_header_generation(buf),
level, 1);
}
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,
parent_start, btrfs_header_owner(parent),
btrfs_header_generation(parent), level, 1);
}
if (unlock_orig)
btrfs_tree_unlock(buf);
free_extent_buffer(buf);
btrfs_mark_buffer_dirty(cow);
*cow_ret = cow;
return 0;
}
/*
* cows a single block, see __btrfs_cow_block for the real work.
* This version of it has extra checks so that a block isn't cow'd more than
* once per transaction, as long as it hasn't been written yet
*/
int noinline btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret, u64 prealloc_dest)
{
u64 search_start;
int ret;
if (trans->transaction != root->fs_info->running_transaction) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->running_transaction->transid);
WARN_ON(1);
}
if (trans->transid != root->fs_info->generation) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->generation);
WARN_ON(1);
}
spin_lock(&root->fs_info->hash_lock);
if (btrfs_header_generation(buf) == trans->transid &&
btrfs_header_owner(buf) == root->root_key.objectid &&
!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
*cow_ret = buf;
spin_unlock(&root->fs_info->hash_lock);
WARN_ON(prealloc_dest);
return 0;
}
spin_unlock(&root->fs_info->hash_lock);
search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
ret = __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0,
prealloc_dest);
return ret;
}
/*
* helper function for defrag to decide if two blocks pointed to by a
* node are actually close by
*/
static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
{
if (blocknr < other && other - (blocknr + blocksize) < 32768)
return 1;
if (blocknr > other && blocknr - (other + blocksize) < 32768)
return 1;
return 0;
}
/*
* compare two keys in a memcmp fashion
*/
static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
{
struct btrfs_key k1;
btrfs_disk_key_to_cpu(&k1, disk);
if (k1.objectid > k2->objectid)
return 1;
if (k1.objectid < k2->objectid)
return -1;
if (k1.type > k2->type)
return 1;
if (k1.type < k2->type)
return -1;
if (k1.offset > k2->offset)
return 1;
if (k1.offset < k2->offset)
return -1;
return 0;
}
/*
* this is used by the defrag code to go through all the
* leaves pointed to by a node and reallocate them so that
* disk order is close to key order
*/
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *parent,
int start_slot, int cache_only, u64 *last_ret,
struct btrfs_key *progress)
{
struct extent_buffer *cur;
u64 blocknr;
u64 gen;
u64 search_start = *last_ret;
u64 last_block = 0;
u64 other;
u32 parent_nritems;
int end_slot;
int i;
int err = 0;
int parent_level;
int uptodate;
u32 blocksize;
int progress_passed = 0;
struct btrfs_disk_key disk_key;
parent_level = btrfs_header_level(parent);
if (cache_only && parent_level != 1)
return 0;
if (trans->transaction != root->fs_info->running_transaction) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->running_transaction->transid);
WARN_ON(1);
}
if (trans->transid != root->fs_info->generation) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->generation);
WARN_ON(1);
}
parent_nritems = btrfs_header_nritems(parent);
blocksize = btrfs_level_size(root, parent_level - 1);
end_slot = parent_nritems;
if (parent_nritems == 1)
return 0;
for (i = start_slot; i < end_slot; i++) {
int close = 1;
if (!parent->map_token) {
map_extent_buffer(parent,
btrfs_node_key_ptr_offset(i),
sizeof(struct btrfs_key_ptr),
&parent->map_token, &parent->kaddr,
&parent->map_start, &parent->map_len,
KM_USER1);
}
btrfs_node_key(parent, &disk_key, i);
if (!progress_passed && comp_keys(&disk_key, progress) < 0)
continue;
progress_passed = 1;
blocknr = btrfs_node_blockptr(parent, i);
gen = btrfs_node_ptr_generation(parent, i);
if (last_block == 0)
last_block = blocknr;
if (i > 0) {
other = btrfs_node_blockptr(parent, i - 1);
close = close_blocks(blocknr, other, blocksize);
}
if (!close && i < end_slot - 2) {
other = btrfs_node_blockptr(parent, i + 1);
close = close_blocks(blocknr, other, blocksize);
}
if (close) {
last_block = blocknr;
continue;
}
if (parent->map_token) {
unmap_extent_buffer(parent, parent->map_token,
KM_USER1);
parent->map_token = NULL;
}
cur = btrfs_find_tree_block(root, blocknr, blocksize);
if (cur)
uptodate = btrfs_buffer_uptodate(cur, gen);
else
uptodate = 0;
if (!cur || !uptodate) {
if (cache_only) {
free_extent_buffer(cur);
continue;
}
if (!cur) {
cur = read_tree_block(root, blocknr,
blocksize, gen);
} else if (!uptodate) {
btrfs_read_buffer(cur, gen);
}
}
if (search_start == 0)
search_start = last_block;
btrfs_tree_lock(cur);
err = __btrfs_cow_block(trans, root, cur, parent, i,
&cur, search_start,
min(16 * blocksize,
(end_slot - i) * blocksize), 0);
if (err) {
btrfs_tree_unlock(cur);
free_extent_buffer(cur);
break;
}
search_start = cur->start;
last_block = cur->start;
*last_ret = search_start;
btrfs_tree_unlock(cur);
free_extent_buffer(cur);
}
if (parent->map_token) {
unmap_extent_buffer(parent, parent->map_token,
KM_USER1);
parent->map_token = NULL;
}
return err;
}
/*
* The leaf data grows from end-to-front in the node.
* this returns the address of the start of the last item,
* which is the stop of the leaf data stack
*/
static inline unsigned int leaf_data_end(struct btrfs_root *root,
struct extent_buffer *leaf)
{
u32 nr = btrfs_header_nritems(leaf);
if (nr == 0)
return BTRFS_LEAF_DATA_SIZE(root);
return btrfs_item_offset_nr(leaf, nr - 1);
}
/*
* extra debugging checks to make sure all the items in a key are
* well formed and in the proper order
*/
static int check_node(struct btrfs_root *root, struct btrfs_path *path,
int level)
{
struct extent_buffer *parent = NULL;
struct extent_buffer *node = path->nodes[level];
struct btrfs_disk_key parent_key;
struct btrfs_disk_key node_key;
int parent_slot;
int slot;
struct btrfs_key cpukey;
u32 nritems = btrfs_header_nritems(node);
if (path->nodes[level + 1])
parent = path->nodes[level + 1];
slot = path->slots[level];
BUG_ON(nritems == 0);
if (parent) {
parent_slot = path->slots[level + 1];
btrfs_node_key(parent, &parent_key, parent_slot);
btrfs_node_key(node, &node_key, 0);
BUG_ON(memcmp(&parent_key, &node_key,
sizeof(struct btrfs_disk_key)));
BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
btrfs_header_bytenr(node));
}
BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
if (slot != 0) {
btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
btrfs_node_key(node, &node_key, slot);
BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
}
if (slot < nritems - 1) {
btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
btrfs_node_key(node, &node_key, slot);
BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
}
return 0;
}
/*
* extra checking to make sure all the items in a leaf are
* well formed and in the proper order
*/
static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
int level)
{
struct extent_buffer *leaf = path->nodes[level];
struct extent_buffer *parent = NULL;
int parent_slot;
struct btrfs_key cpukey;
struct btrfs_disk_key parent_key;
struct btrfs_disk_key leaf_key;
int slot = path->slots[0];
u32 nritems = btrfs_header_nritems(leaf);
if (path->nodes[level + 1])
parent = path->nodes[level + 1];
if (nritems == 0)
return 0;
if (parent) {
parent_slot = path->slots[level + 1];
btrfs_node_key(parent, &parent_key, parent_slot);
btrfs_item_key(leaf, &leaf_key, 0);
BUG_ON(memcmp(&parent_key, &leaf_key,
sizeof(struct btrfs_disk_key)));
BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
btrfs_header_bytenr(leaf));
}
#if 0
for (i = 0; nritems > 1 && i < nritems - 2; i++) {
btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
btrfs_item_key(leaf, &leaf_key, i);
if (comp_keys(&leaf_key, &cpukey) >= 0) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad key\n", i);
BUG_ON(1);
}
if (btrfs_item_offset_nr(leaf, i) !=
btrfs_item_end_nr(leaf, i + 1)) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad\n", i);
BUG_ON(1);
}
if (i == 0) {
if (btrfs_item_offset_nr(leaf, i) +
btrfs_item_size_nr(leaf, i) !=
BTRFS_LEAF_DATA_SIZE(root)) {
btrfs_print_leaf(root, leaf);
printk("slot %d first offset bad\n", i);
BUG_ON(1);
}
}
}
if (nritems > 0) {
if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
btrfs_print_leaf(root, leaf);
printk("slot %d bad size \n", nritems - 1);
BUG_ON(1);
}
}
#endif
if (slot != 0 && slot < nritems - 1) {
btrfs_item_key(leaf, &leaf_key, slot);
btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
if (comp_keys(&leaf_key, &cpukey) <= 0) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad key\n", slot);
BUG_ON(1);
}
if (btrfs_item_offset_nr(leaf, slot - 1) !=
btrfs_item_end_nr(leaf, slot)) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad\n", slot);
BUG_ON(1);
}
}
if (slot < nritems - 1) {
btrfs_item_key(leaf, &leaf_key, slot);
btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
if (btrfs_item_offset_nr(leaf, slot) !=
btrfs_item_end_nr(leaf, slot + 1)) {
btrfs_print_leaf(root, leaf);
printk("slot %d offset bad\n", slot);
BUG_ON(1);
}
}
BUG_ON(btrfs_item_offset_nr(leaf, 0) +
btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
return 0;
}
static int noinline check_block(struct btrfs_root *root,
struct btrfs_path *path, int level)
{
u64 found_start;
return 0;
if (btrfs_header_level(path->nodes[level]) != level)
printk("warning: bad level %Lu wanted %d found %d\n",
path->nodes[level]->start, level,
btrfs_header_level(path->nodes[level]));
found_start = btrfs_header_bytenr(path->nodes[level]);
if (found_start != path->nodes[level]->start) {
printk("warning: bad bytentr %Lu found %Lu\n",
path->nodes[level]->start, found_start);
}
#if 0
struct extent_buffer *buf = path->nodes[level];
if (memcmp_extent_buffer(buf, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(buf),
BTRFS_FSID_SIZE)) {
printk("warning bad block %Lu\n", buf->start);
return 1;
}
#endif
if (level == 0)
return check_leaf(root, path, level);
return check_node(root, path, level);
}
/*
* search for key in the extent_buffer. The items start at offset p,
* and they are item_size apart. There are 'max' items in p.
*
* the slot in the array is returned via slot, and it points to
* the place where you would insert key if it is not found in
* the array.
*
* slot may point to max if the key is bigger than all of the keys
*/
static noinline int generic_bin_search(struct extent_buffer *eb,
unsigned long p,
int item_size, struct btrfs_key *key,
int max, int *slot)
{
int low = 0;
int high = max;
int mid;
int ret;
struct btrfs_disk_key *tmp = NULL;
struct btrfs_disk_key unaligned;
unsigned long offset;
char *map_token = NULL;
char *kaddr = NULL;
unsigned long map_start = 0;
unsigned long map_len = 0;
int err;
while(low < high) {
mid = (low + high) / 2;
offset = p + mid * item_size;
if (!map_token || offset < map_start ||
(offset + sizeof(struct btrfs_disk_key)) >
map_start + map_len) {
if (map_token) {
unmap_extent_buffer(eb, map_token, KM_USER0);
map_token = NULL;
}
err = map_extent_buffer(eb, offset,
sizeof(struct btrfs_disk_key),
&map_token, &kaddr,
&map_start, &map_len, KM_USER0);
if (!err) {
tmp = (struct btrfs_disk_key *)(kaddr + offset -
map_start);
} else {
read_extent_buffer(eb, &unaligned,
offset, sizeof(unaligned));
tmp = &unaligned;
}
} else {
tmp = (struct btrfs_disk_key *)(kaddr + offset -
map_start);
}
ret = comp_keys(tmp, key);
if (ret < 0)
low = mid + 1;
else if (ret > 0)
high = mid;
else {
*slot = mid;
if (map_token)
unmap_extent_buffer(eb, map_token, KM_USER0);
return 0;
}
}
*slot = low;
if (map_token)
unmap_extent_buffer(eb, map_token, KM_USER0);
return 1;
}
/*
* simple bin_search frontend that does the right thing for
* leaves vs nodes
*/
static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
int level, int *slot)
{
if (level == 0) {
return generic_bin_search(eb,
offsetof(struct btrfs_leaf, items),
sizeof(struct btrfs_item),
key, btrfs_header_nritems(eb),
slot);
} else {
return generic_bin_search(eb,
offsetof(struct btrfs_node, ptrs),
sizeof(struct btrfs_key_ptr),
key, btrfs_header_nritems(eb),
slot);
}
return -1;
}
/* given a node and slot number, this reads the blocks it points to. The
* extent buffer is returned with a reference taken (but unlocked).
* NULL is returned on error.
*/
static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
struct extent_buffer *parent, int slot)
{
int level = btrfs_header_level(parent);
if (slot < 0)
return NULL;
if (slot >= btrfs_header_nritems(parent))
return NULL;
BUG_ON(level == 0);
return read_tree_block(root, btrfs_node_blockptr(parent, slot),
btrfs_level_size(root, level - 1),
btrfs_node_ptr_generation(parent, slot));
}
/*
* 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 extent_buffer *right = NULL;
struct extent_buffer *mid;
struct extent_buffer *left = NULL;
struct extent_buffer *parent = NULL;
int ret = 0;
int wret;
int pslot;
int orig_slot = path->slots[level];
int err_on_enospc = 0;
u64 orig_ptr;
if (level == 0)
return 0;
mid = path->nodes[level];
WARN_ON(!path->locks[level]);
WARN_ON(btrfs_header_generation(mid) != trans->transid);
orig_ptr = btrfs_node_blockptr(mid, orig_slot);
if (level < BTRFS_MAX_LEVEL - 1)
parent = path->nodes[level + 1];
pslot = path->slots[level + 1];
/*
* deal with the case where there is only one pointer in the root
* by promoting the node below to a root
*/
if (!parent) {
struct extent_buffer *child;
if (btrfs_header_nritems(mid) != 1)
return 0;
/* promote the child to a root */
child = read_node_slot(root, mid, 0);
btrfs_tree_lock(child);
BUG_ON(!child);
ret = btrfs_cow_block(trans, root, child, mid, 0, &child, 0);
BUG_ON(ret);
spin_lock(&root->node_lock);
root->node = child;
spin_unlock(&root->node_lock);
ret = btrfs_update_extent_ref(trans, root, child->start,
mid->start, child->start,
root->root_key.objectid,
trans->transid, level - 1);
BUG_ON(ret);
add_root_to_dirty_list(root);
btrfs_tree_unlock(child);
path->locks[level] = 0;
path->nodes[level] = NULL;
clean_tree_block(trans, root, mid);
btrfs_tree_unlock(mid);
/* once for the path */
free_extent_buffer(mid);
ret = btrfs_free_extent(trans, root, mid->start, mid->len,
mid->start, root->root_key.objectid,
btrfs_header_generation(mid),
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;
if (btrfs_header_nritems(mid) < 2)
err_on_enospc = 1;
left = read_node_slot(root, parent, pslot - 1);
if (left) {
btrfs_tree_lock(left);
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left, 0);
if (wret) {
ret = wret;
goto enospc;
}
}
right = read_node_slot(root, parent, pslot + 1);
if (right) {
btrfs_tree_lock(right);
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right, 0);
if (wret) {
ret = wret;
goto enospc;
}
}
/* first, try to make some room in the middle buffer */
if (left) {
orig_slot += btrfs_header_nritems(left);
wret = push_node_left(trans, root, left, mid, 1);
if (wret < 0)
ret = wret;
if (btrfs_header_nritems(mid) < 2)
err_on_enospc = 1;
}
/*
* then try to empty the right most buffer into the middle
*/
if (right) {
wret = push_node_left(trans, root, mid, right, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
if (btrfs_header_nritems(right) == 0) {
u64 bytenr = right->start;
u64 generation = btrfs_header_generation(parent);
u32 blocksize = right->len;
clean_tree_block(trans, root, right);
btrfs_tree_unlock(right);
free_extent_buffer(right);
right = NULL;
wret = del_ptr(trans, root, path, level + 1, pslot +
1);
if (wret)
ret = wret;
wret = btrfs_free_extent(trans, root, bytenr,
blocksize, parent->start,
btrfs_header_owner(parent),
generation, level, 1);
if (wret)
ret = wret;
} else {
struct btrfs_disk_key right_key;
btrfs_node_key(right, &right_key, 0);
btrfs_set_node_key(parent, &right_key, pslot + 1);
btrfs_mark_buffer_dirty(parent);
}
}
if (btrfs_header_nritems(mid) == 1) {
/*
* we're not allowed to leave a node with one item in the
* tree during a delete. A deletion from lower in the tree
* could try to delete the only pointer in this node.
* So, pull some keys from the left.
* There has to be a left pointer at this point because
* otherwise we would have pulled some pointers from the
* right
*/
BUG_ON(!left);
wret = balance_node_right(trans, root, mid, left);
if (wret < 0) {
ret = wret;
goto enospc;
}
if (wret == 1) {
wret = push_node_left(trans, root, left, mid, 1);
if (wret < 0)
ret = wret;
}
BUG_ON(wret == 1);
}
if (btrfs_header_nritems(mid) == 0) {
/* we've managed to empty the middle node, drop it */
u64 root_gen = btrfs_header_generation(parent);
u64 bytenr = mid->start;
u32 blocksize = mid->len;
clean_tree_block(trans, root, mid);
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
mid = NULL;
wret = del_ptr(trans, root, path, level + 1, pslot);
if (wret)
ret = wret;
wret = btrfs_free_extent(trans, root, bytenr, blocksize,
parent->start,
btrfs_header_owner(parent),
root_gen, level, 1);
if (wret)
ret = wret;
} else {
/* update the parent key to reflect our changes */
struct btrfs_disk_key mid_key;
btrfs_node_key(mid, &mid_key, 0);
btrfs_set_node_key(parent, &mid_key, pslot);
btrfs_mark_buffer_dirty(parent);
}
/* update the path */
if (left) {
if (btrfs_header_nritems(left) > orig_slot) {
extent_buffer_get(left);
/* left was locked after cow */
path->nodes[level] = left;
path->slots[level + 1] -= 1;
path->slots[level] = orig_slot;
if (mid) {
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
}
} else {
orig_slot -= btrfs_header_nritems(left);
path->slots[level] = orig_slot;
}
}
/* double check we haven't messed things up */
check_block(root, path, level);
if (orig_ptr !=
btrfs_node_blockptr(path->nodes[level], path->slots[level]))
BUG();
enospc:
if (right) {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
if (left) {
if (path->nodes[level] != left)
btrfs_tree_unlock(left);
free_extent_buffer(left);
}
return ret;
}
/* 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 int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
struct extent_buffer *right = NULL;
struct extent_buffer *mid;
struct extent_buffer *left = NULL;
struct extent_buffer *parent = NULL;
int ret = 0;
int wret;
int pslot;
int orig_slot = path->slots[level];
u64 orig_ptr;
if (level == 0)
return 1;
mid = path->nodes[level];
WARN_ON(btrfs_header_generation(mid) != trans->transid);
orig_ptr = btrfs_node_blockptr(mid, orig_slot);
if (level < BTRFS_MAX_LEVEL - 1)
parent = path->nodes[level + 1];
pslot = path->slots[level + 1];
if (!parent)
return 1;
left = read_node_slot(root, parent, pslot - 1);
/* first, try to make some room in the middle buffer */
if (left) {
u32 left_nr;
btrfs_tree_lock(left);
left_nr = btrfs_header_nritems(left);
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, left, parent,
pslot - 1, &left, 0);
if (ret)
wret = 1;
else {
wret = push_node_left(trans, root,
left, mid, 0);
}
}
if (wret < 0)
ret = wret;
if (wret == 0) {
struct btrfs_disk_key disk_key;
orig_slot += left_nr;
btrfs_node_key(mid, &disk_key, 0);
btrfs_set_node_key(parent, &disk_key, pslot);
btrfs_mark_buffer_dirty(parent);
if (btrfs_header_nritems(left) > orig_slot) {
path->nodes[level] = left;
path->slots[level + 1] -= 1;
path->slots[level] = orig_slot;
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
} else {
orig_slot -=
btrfs_header_nritems(left);
path->slots[level] = orig_slot;
btrfs_tree_unlock(left);
free_extent_buffer(left);
}
return 0;
}
btrfs_tree_unlock(left);
free_extent_buffer(left);
}
right = read_node_slot(root, parent, pslot + 1);
/*
* then try to empty the right most buffer into the middle
*/
if (right) {
u32 right_nr;
btrfs_tree_lock(right);
right_nr = btrfs_header_nritems(right);
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, right,
parent, pslot + 1,
&right, 0);
if (ret)
wret = 1;
else {
wret = balance_node_right(trans, root,
right, mid);
}
}
if (wret < 0)
ret = wret;
if (wret == 0) {
struct btrfs_disk_key disk_key;
btrfs_node_key(right, &disk_key, 0);
btrfs_set_node_key(parent, &disk_key, pslot + 1);
btrfs_mark_buffer_dirty(parent);
if (btrfs_header_nritems(mid) <= orig_slot) {
path->nodes[level] = right;
path->slots[level + 1] += 1;
path->slots[level] = orig_slot -
btrfs_header_nritems(mid);
btrfs_tree_unlock(mid);
free_extent_buffer(mid);
} else {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
return 0;
}
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
return 1;
}
/*
* readahead one full node of leaves, finding things that are close
* to the block in 'slot', and triggering ra on them.
*/
static noinline 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;
}
}
/*
* when we walk down the tree, it is usually safe to unlock the higher layers in
* the tree. The exceptions are when our path goes through slot 0, because operations
* on the tree might require changing key pointers higher up in the tree.
*
* callers might also have set path->keep_locks, which tells this code to
* keep the lock if the path points to the last slot in the block. This is
* part of walking through the tree, and selecting the next slot in the higher
* block.
*
* lowest_unlock sets the lowest level in the tree we're allowed to unlock.
* so if lowest_unlock is 1, level 0 won't be unlocked
*/
static noinline void unlock_up(struct btrfs_path *path, int level,
int lowest_unlock)
{
int i;
int skip_level = level;
int no_skips = 0;
struct extent_buffer *t;
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
if (!path->nodes[i])
break;
if (!path->locks[i])
break;
if (!no_skips && path->slots[i] == 0) {
skip_level = i + 1;
continue;
}
if (!no_skips && path->keep_locks) {
u32 nritems;
t = path->nodes[i];
nritems = btrfs_header_nritems(t);
if (nritems < 1 || path->slots[i] >= nritems - 1) {
skip_level = i + 1;
continue;
}
}
if (skip_level < i && i >= lowest_unlock)
no_skips = 1;
t = path->nodes[i];
if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
btrfs_tree_unlock(t);
path->locks[i] = 0;
}
}
}
/*
* look for key in the tree. path is filled in with nodes along the way
* if key is found, we return zero and you can find the item in the leaf
* level of the path (level 0)
*
* If the key isn't found, the path points to the slot where it should
* be inserted, and 1 is returned. If there are other errors during the
* search a negative error number is returned.
*
* if ins_len > 0, nodes and leaves will be split as we walk down the
* tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
* possible)
*/
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *key, struct btrfs_path *p, int
ins_len, int cow)
{
struct extent_buffer *b;
struct extent_buffer *tmp;
int slot;
int ret;
int level;
int should_reada = p->reada;
int lowest_unlock = 1;
int blocksize;
u8 lowest_level = 0;
u64 blocknr;
u64 gen;
struct btrfs_key prealloc_block;
lowest_level = p->lowest_level;
WARN_ON(lowest_level && ins_len > 0);
WARN_ON(p->nodes[0] != NULL);
if (ins_len < 0)
lowest_unlock = 2;
prealloc_block.objectid = 0;
again:
if (p->skip_locking)
b = btrfs_root_node(root);
else
b = btrfs_lock_root_node(root);
while (b) {
level = btrfs_header_level(b);
/*
* setup the path here so we can release it under lock
* contention with the cow code
*/
p->nodes[level] = b;
if (!p->skip_locking)
p->locks[level] = 1;
if (cow) {
int wret;
/* is a cow on this block not required */
spin_lock(&root->fs_info->hash_lock);
if (btrfs_header_generation(b) == trans->transid &&
btrfs_header_owner(b) == root->root_key.objectid &&
!btrfs_header_flag(b, BTRFS_HEADER_FLAG_WRITTEN)) {
spin_unlock(&root->fs_info->hash_lock);
goto cow_done;
}
spin_unlock(&root->fs_info->hash_lock);
/* ok, we have to cow, is our old prealloc the right
* size?
*/
if (prealloc_block.objectid &&
prealloc_block.offset != b->len) {
btrfs_free_reserved_extent(root,
prealloc_block.objectid,
prealloc_block.offset);
prealloc_block.objectid = 0;
}
/*
* for higher level blocks, try not to allocate blocks
* with the block and the parent locks held.
*/
if (level > 1 && !prealloc_block.objectid &&
btrfs_path_lock_waiting(p, level)) {
u32 size = b->len;
u64 hint = b->start;
btrfs_release_path(root, p);
ret = btrfs_reserve_extent(trans, root,
size, size, 0,
hint, (u64)-1,
&prealloc_block, 0);
BUG_ON(ret);
goto again;
}
wret = btrfs_cow_block(trans, root, b,
p->nodes[level + 1],
p->slots[level + 1],
&b, prealloc_block.objectid);
prealloc_block.objectid = 0;
if (wret) {
free_extent_buffer(b);
ret = wret;
goto done;
}
}
cow_done:
BUG_ON(!cow && ins_len);
if (level != btrfs_header_level(b))
WARN_ON(1);
level = btrfs_header_level(b);
p->nodes[level] = b;
if (!p->skip_locking)
p->locks[level] = 1;
ret = check_block(root, p, level);
if (ret) {
ret = -1;
goto done;
}
ret = bin_search(b, key, level, &slot);
if (level != 0) {
if (ret && slot > 0)
slot -= 1;
p->slots[level] = slot;
if (ins_len > 0 && btrfs_header_nritems(b) >=
BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
int sret = split_node(trans, root, p, level);
BUG_ON(sret > 0);
if (sret) {
ret = sret;
goto done;
}
b = p->nodes[level];
slot = p->slots[level];
} else if (ins_len < 0) {
int sret = balance_level(trans, root, p,
level);
if (sret) {
ret = sret;
goto done;
}
b = p->nodes[level];
if (!b) {
btrfs_release_path(NULL, p);
goto again;
}
slot = p->slots[level];
BUG_ON(btrfs_header_nritems(b) == 1);
}
unlock_up(p, level, lowest_unlock);
/* this is only true while dropping a snapshot */
if (level == lowest_level) {
ret = 0;
goto done;
}
blocknr = btrfs_node_blockptr(b, slot);
gen = btrfs_node_ptr_generation(b, slot);
blocksize = btrfs_level_size(root, level - 1);
tmp = btrfs_find_tree_block(root, blocknr, blocksize);
if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
b = tmp;
} else {
/*
* reduce lock contention at high levels
* of the btree by dropping locks before
* we read.
*/
if (level > 1) {
btrfs_release_path(NULL, p);
if (tmp)
free_extent_buffer(tmp);
if (should_reada)
reada_for_search(root, p,
level, slot,
key->objectid);
tmp = read_tree_block(root, blocknr,
blocksize, gen);
if (tmp)
free_extent_buffer(tmp);
goto again;
} else {
if (tmp)
free_extent_buffer(tmp);
if (should_reada)
reada_for_search(root, p,
level, slot,
key->objectid);
b = read_node_slot(root, b, slot);
}
}
if (!p->skip_locking)
btrfs_tree_lock(b);
} else {
p->slots[level] = slot;
if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
sizeof(struct btrfs_item) + ins_len) {
int sret = split_leaf(trans, root, key,
p, ins_len, ret == 0);
BUG_ON(sret > 0);
if (sret) {
ret = sret;
goto done;
}
}
unlock_up(p, level, lowest_unlock);
goto done;
}
}
ret = 1;
done:
if (prealloc_block.objectid) {
btrfs_free_reserved_extent(root,
prealloc_block.objectid,
prealloc_block.offset);
}
return ret;
}
int btrfs_merge_path(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_key *node_keys,
u64 *nodes, int lowest_level)
{
struct extent_buffer *eb;
struct extent_buffer *parent;
struct btrfs_key key;
u64 bytenr;
u64 generation;
u32 blocksize;
int level;
int slot;
int key_match;
int ret;
eb = btrfs_lock_root_node(root);
ret = btrfs_cow_block(trans, root, eb, NULL, 0, &eb, 0);
BUG_ON(ret);
parent = eb;
while (1) {
level = btrfs_header_level(parent);
if (level == 0 || level <= lowest_level)
break;
ret = bin_search(parent, &node_keys[lowest_level], level,
&slot);
if (ret && slot > 0)
slot--;
bytenr = btrfs_node_blockptr(parent, slot);
if (nodes[level - 1] == bytenr)
break;
blocksize = btrfs_level_size(root, level - 1);
generation = btrfs_node_ptr_generation(parent, slot);
btrfs_node_key_to_cpu(eb, &key, slot);
key_match = !memcmp(&key, &node_keys[level - 1], sizeof(key));
if (generation == trans->transid) {
eb = read_tree_block(root, bytenr, blocksize,
generation);
btrfs_tree_lock(eb);
}
/*
* if node keys match and node pointer hasn't been modified
* in the running transaction, we can merge the path. for
* blocks owened by reloc trees, the node pointer check is
* skipped, this is because these blocks are fully controlled
* by the space balance code, no one else can modify them.
*/
if (!nodes[level - 1] || !key_match ||
(generation == trans->transid &&
btrfs_header_owner(eb) != BTRFS_TREE_RELOC_OBJECTID)) {
if (level == 1 || level == lowest_level + 1) {
if (generation == trans->transid) {
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
}
break;
}
if (generation != trans->transid) {
eb = read_tree_block(root, bytenr, blocksize,
generation);
btrfs_tree_lock(eb);
}
ret = btrfs_cow_block(trans, root, eb, parent, slot,
&eb, 0);
BUG_ON(ret);
if (root->root_key.objectid ==
BTRFS_TREE_RELOC_OBJECTID) {
if (!nodes[level - 1]) {
nodes[level - 1] = eb->start;
memcpy(&node_keys[level - 1], &key,
sizeof(node_keys[0]));
} else {
WARN_ON(1);
}
}
btrfs_tree_unlock(parent);
free_extent_buffer(parent);
parent = eb;
continue;
}
btrfs_set_node_blockptr(parent, slot, nodes[level - 1]);
btrfs_set_node_ptr_generation(parent, slot, trans->transid);
btrfs_mark_buffer_dirty(parent);
ret = btrfs_inc_extent_ref(trans, root,
nodes[level - 1],
blocksize, parent->start,
btrfs_header_owner(parent),
btrfs_header_generation(parent),
level - 1);
BUG_ON(ret);
/*
* If the block was created in the running transaction,
* it's possible this is the last reference to it, so we
* should drop the subtree.
*/
if (generation == trans->transid) {
ret = btrfs_drop_subtree(trans, root, eb, parent);
BUG_ON(ret);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
} else {
ret = btrfs_free_extent(trans, root, bytenr,
blocksize, parent->start,
btrfs_header_owner(parent),
btrfs_header_generation(parent),
level - 1, 1);
BUG_ON(ret);
}
break;
}
btrfs_tree_unlock(parent);
free_extent_buffer(parent);
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
*
* If this fails to write a tree block, it returns -1, but continues
* fixing up the blocks in ram so the tree is consistent.
*/
static int fixup_low_keys(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_disk_key *key, int level)
{
int i;
int ret = 0;
struct extent_buffer *t;
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
int tslot = path->slots[i];
if (!path->nodes[i])
break;
t = path->nodes[i];
btrfs_set_node_key(t, key, tslot);
btrfs_mark_buffer_dirty(path->nodes[i]);
if (tslot != 0)
break;
}
return ret;
}
/*
* 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_trans_handle *trans,
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 (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 (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)
fixup_low_keys(trans, root, path, &disk_key, 1);
return 0;
}
/*
* 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);
ret = btrfs_update_ref(trans, root, src, dst, dst_nritems, push_items);
BUG_ON(ret);
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);
ret = btrfs_update_ref(trans, root, src, dst, 0, push_items);
BUG_ON(ret);
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;
int ret;
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, 0,
root->root_key.objectid, trans->transid,
level, root->node->start, 0);
if (IS_ERR(c))
return PTR_ERR(c);
memset_extent_buffer(c, 0, 0, root->nodesize);
btrfs_set_header_nritems(c, 1);
btrfs_set_header_level(c, level);
btrfs_set_header_bytenr(c, c->start);
btrfs_set_header_generation(c, trans->transid);
btrfs_set_header_owner(c, root->root_key.objectid);
write_extent_buffer(c, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(c),
BTRFS_FSID_SIZE);
write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
(unsigned long)btrfs_header_chunk_tree_uuid(c),
BTRFS_UUID_SIZE);
btrfs_set_node_key(c, &lower_key, 0);
btrfs_set_node_blockptr(c, 0, lower->start);
lower_gen = btrfs_header_generation(lower);
WARN_ON(lower_gen != trans->transid);
btrfs_set_node_ptr_generation(c, 0, lower_gen);
btrfs_mark_buffer_dirty(c);
spin_lock(&root->node_lock);
old = root->node;
root->node = c;
spin_unlock(&root->node_lock);
ret = btrfs_update_extent_ref(trans, root, lower->start,
lower->start, c->start,
root->root_key.objectid,
trans->transid, level - 1);
BUG_ON(ret);
/* the super has an extra ref to root->node */
free_extent_buffer(old);
add_root_to_dirty_list(root);
extent_buffer_get(c);
path->nodes[level] = c;
path->locks[level] = 1;
path->slots[level] = 0;
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 noinline 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);
split = btrfs_alloc_free_block(trans, root, root->nodesize,
path->nodes[level + 1]->start,
root->root_key.objectid,
trans->transid, level, c->start, 0);
if (IS_ERR(split))
return PTR_ERR(split);
btrfs_set_header_flags(split, btrfs_header_flags(c));
btrfs_set_header_level(split, btrfs_header_level(c));
btrfs_set_header_bytenr(split, split->start);
btrfs_set_header_generation(split, trans->transid);
btrfs_set_header_owner(split, root->root_key.objectid);
btrfs_set_header_flags(split, 0);
write_extent_buffer(split, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(split),
BTRFS_FSID_SIZE);
write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
(unsigned long)btrfs_header_chunk_tree_uuid(split),
BTRFS_UUID_SIZE);
mid = (c_nritems + 1) / 2;
copy_extent_buffer(split, c,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(mid),
(c_nritems - mid) * sizeof(struct btrfs_key_ptr));
btrfs_set_header_nritems(split, c_nritems - mid);
btrfs_set_header_nritems(c, mid);
ret = 0;
btrfs_mark_buffer_dirty(c);
btrfs_mark_buffer_dirty(split);
btrfs_node_key(split, &disk_key, 0);
wret = insert_ptr(trans, root, path, &disk_key, split->start,
path->slots[level + 1] + 1,
level + 1);
if (wret)
ret = wret;
ret = btrfs_update_ref(trans, root, c, split, 0, c_nritems - mid);
BUG_ON(ret);
if (path->slots[level] >= mid) {
path->slots[level] -= mid;
btrfs_tree_unlock(c);
free_extent_buffer(c);
path->nodes[level] = split;
path->slots[level + 1] += 1;
} else {
btrfs_tree_unlock(split);
free_extent_buffer(split);
}
return ret;
}
/*
* how many bytes are required to store the items in a leaf. start
* and nr indicate which items in the leaf to check. This totals up the
* space used both by the item structs and the item data
*/
static int leaf_space_used(struct extent_buffer *l, int start, int nr)
{
int data_len;
int nritems = btrfs_header_nritems(l);
int end = min(nritems, start + nr) - 1;
if (!nr)
return 0;
data_len = btrfs_item_end_nr(l, start);
data_len = data_len - btrfs_item_offset_nr(l, end);
data_len += sizeof(struct btrfs_item) * nr;
WARN_ON(data_len < 0);
return data_len;
}
/*
* The space between the end of the leaf items and
* the start of the leaf data. IOW, how much room
* the leaf has left for both items and data
*/
int noinline btrfs_leaf_free_space(struct btrfs_root *root,
struct extent_buffer *leaf)
{
int nritems = btrfs_header_nritems(leaf);
int ret;
ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
if (ret < 0) {
printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
leaf_space_used(leaf, 0, nritems), nritems);
}
return ret;
}
/*
* push some data in the path leaf to the right, trying to free up at
* least data_size bytes. returns zero if the push worked, nonzero otherwise
*
* returns 1 if the push failed because the other node didn't have enough
* room, 0 if everything worked out and < 0 if there were major errors.
*/
static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int data_size,
int empty)
{
struct extent_buffer *left = path->nodes[0];
struct extent_buffer *right;
struct extent_buffer *upper;
struct btrfs_disk_key disk_key;
int slot;
u32 i;
int free_space;
int push_space = 0;
int push_items = 0;
struct btrfs_item *item;
u32 left_nritems;
u32 nr;
u32 right_nritems;
u32 data_end;
u32 this_item_size;
int ret;
slot = path->slots[1];
if (!path->nodes[1]) {
return 1;
}
upper = path->nodes[1];
if (slot >= btrfs_header_nritems(upper) - 1)
return 1;
WARN_ON(!btrfs_tree_locked(path->nodes[1]));
right = read_node_slot(root, upper, slot + 1);
btrfs_tree_lock(right);
free_space = btrfs_leaf_free_space(root, right);
if (free_space < data_size + sizeof(struct btrfs_item))
goto out_unlock;
/* cow and double check */
ret = btrfs_cow_block(trans, root, right, upper,
slot + 1, &right, 0);
if (ret)
goto out_unlock;
free_space = btrfs_leaf_free_space(root, right);
if (free_space < data_size + sizeof(struct btrfs_item))
goto out_unlock;
left_nritems = btrfs_header_nritems(left);
if (left_nritems == 0)
goto out_unlock;
if (empty)
nr = 0;
else
nr = 1;
if (path->slots[0] >= left_nritems)
push_space += data_size + sizeof(*item);
i = left_nritems - 1;
while (i >= nr) {
item = btrfs_item_nr(left, i);
if (!empty && push_items > 0) {
if (path->slots[0] > i)
break;
if (path->slots[0] == i) {
int space = btrfs_leaf_free_space(root, left);
if (space + push_space * 2 > free_space)
break;
}
}
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
if (!left->map_token) {
map_extent_buffer(left, (unsigned long)item,
sizeof(struct btrfs_item),
&left->map_token, &left->kaddr,
&left->map_start, &left->map_len,
KM_USER1);
}
this_item_size = btrfs_item_size(left, item);
if (this_item_size + sizeof(*item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(*item);
if (i == 0)
break;
i--;
}
if (left->map_token) {
unmap_extent_buffer(left, left->map_token, KM_USER1);
left->map_token = NULL;
}
if (push_items == 0)
goto out_unlock;
if (!empty && push_items == left_nritems)
WARN_ON(1);
/* push left to right */
right_nritems = btrfs_header_nritems(right);
push_space = btrfs_item_end_nr(left, left_nritems - push_items);
push_space -= leaf_data_end(root, left);
/* make room in the right data area */
data_end = leaf_data_end(root, right);
memmove_extent_buffer(right,
btrfs_leaf_data(right) + data_end - push_space,
btrfs_leaf_data(right) + data_end,
BTRFS_LEAF_DATA_SIZE(root) - data_end);
/* copy from the left data area */
copy_extent_buffer(right, left, btrfs_leaf_data(right) +
BTRFS_LEAF_DATA_SIZE(root) - push_space,
btrfs_leaf_data(left) + leaf_data_end(root, left),
push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
btrfs_item_nr_offset(0),
right_nritems * sizeof(struct btrfs_item));
/* copy the items from left to right */
copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(left_nritems - push_items),
push_items * sizeof(struct btrfs_item));
/* update the item pointers */
right_nritems += push_items;
btrfs_set_header_nritems(right, right_nritems);
push_space = BTRFS_LEAF_DATA_SIZE(root);
for (i = 0; i < right_nritems; i++) {
item = btrfs_item_nr(right, i);
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
push_space -= btrfs_item_size(right, item);
btrfs_set_item_offset(right, item, push_space);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
left_nritems -= push_items;
btrfs_set_header_nritems(left, left_nritems);
if (left_nritems)
btrfs_mark_buffer_dirty(left);
btrfs_mark_buffer_dirty(right);
ret = btrfs_update_ref(trans, root, left, right, 0, push_items);
BUG_ON(ret);
btrfs_item_key(right, &disk_key, 0);
btrfs_set_node_key(upper, &disk_key, slot + 1);
btrfs_mark_buffer_dirty(upper);
/* then fixup the leaf pointer in the path */
if (path->slots[0] >= left_nritems) {
path->slots[0] -= left_nritems;
if (btrfs_header_nritems(path->nodes[0]) == 0)
clean_tree_block(trans, root, path->nodes[0]);
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[1] += 1;
} else {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
return 0;
out_unlock:
btrfs_tree_unlock(right);
free_extent_buffer(right);
return 1;
}
/*
* push some data in the path leaf to the left, trying to free up at
* least data_size bytes. returns zero if the push worked, nonzero otherwise
*/
static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int data_size,
int empty)
{
struct btrfs_disk_key disk_key;
struct extent_buffer *right = path->nodes[0];
struct extent_buffer *left;
int slot;
int i;
int free_space;
int push_space = 0;
int push_items = 0;
struct btrfs_item *item;
u32 old_left_nritems;
u32 right_nritems;
u32 nr;
int ret = 0;
int wret;
u32 this_item_size;
u32 old_left_item_size;
slot = path->slots[1];
if (slot == 0)
return 1;
if (!path->nodes[1])
return 1;
right_nritems = btrfs_header_nritems(right);
if (right_nritems == 0) {
return 1;
}
WARN_ON(!btrfs_tree_locked(path->nodes[1]));
left = read_node_slot(root, path->nodes[1], slot - 1);
btrfs_tree_lock(left);
free_space = btrfs_leaf_free_space(root, left);
if (free_space < data_size + sizeof(struct btrfs_item)) {
ret = 1;
goto out;
}
/* cow and double check */
ret = btrfs_cow_block(trans, root, left,
path->nodes[1], slot - 1, &left, 0);
if (ret) {
/* we hit -ENOSPC, but it isn't fatal here */
ret = 1;
goto out;
}
free_space = btrfs_leaf_free_space(root, left);
if (free_space < data_size + sizeof(struct btrfs_item)) {
ret = 1;
goto out;
}
if (empty)
nr = right_nritems;
else
nr = right_nritems - 1;
for (i = 0; i < nr; i++) {
item = btrfs_item_nr(right, i);
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
if (!empty && push_items > 0) {
if (path->slots[0] < i)
break;
if (path->slots[0] == i) {
int space = btrfs_leaf_free_space(root, right);
if (space + push_space * 2 > free_space)
break;
}
}
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
this_item_size = btrfs_item_size(right, item);
if (this_item_size + sizeof(*item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(*item);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
if (push_items == 0) {
ret = 1;
goto out;
}
if (!empty && push_items == btrfs_header_nritems(right))
WARN_ON(1);
/* push data from right to left */
copy_extent_buffer(left, right,
btrfs_item_nr_offset(btrfs_header_nritems(left)),
btrfs_item_nr_offset(0),
push_items * sizeof(struct btrfs_item));
push_space = BTRFS_LEAF_DATA_SIZE(root) -
btrfs_item_offset_nr(right, push_items -1);
copy_extent_buffer(left, right, btrfs_leaf_data(left) +
leaf_data_end(root, left) - push_space,
btrfs_leaf_data(right) +
btrfs_item_offset_nr(right, push_items - 1),
push_space);
old_left_nritems = btrfs_header_nritems(left);
BUG_ON(old_left_nritems < 0);
old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
u32 ioff;
item = btrfs_item_nr(left, i);
if (!left->map_token) {
map_extent_buffer(left, (unsigned long)item,
sizeof(struct btrfs_item),
&left->map_token, &left->kaddr,
&left->map_start, &left->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(left, item);
btrfs_set_item_offset(left, item,
ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
}
btrfs_set_header_nritems(left, old_left_nritems + push_items);
if (left->map_token) {
unmap_extent_buffer(left, left->map_token, KM_USER1);
left->map_token = NULL;
}
/* fixup right node */
if (push_items > right_nritems) {
printk("push items %d nr %u\n", push_items, right_nritems);
WARN_ON(1);
}
if (push_items < right_nritems) {
push_space = btrfs_item_offset_nr(right, push_items - 1) -
leaf_data_end(root, right);
memmove_extent_buffer(right, btrfs_leaf_data(right) +
BTRFS_LEAF_DATA_SIZE(root) - push_space,
btrfs_leaf_data(right) +
leaf_data_end(root, right), push_space);
memmove_extent_buffer(right, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(push_items),
(btrfs_header_nritems(right) - push_items) *
sizeof(struct btrfs_item));
}
right_nritems -= push_items;
btrfs_set_header_nritems(right, right_nritems);
push_space = BTRFS_LEAF_DATA_SIZE(root);
for (i = 0; i < right_nritems; i++) {
item = btrfs_item_nr(right, i);
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
push_space = push_space - btrfs_item_size(right, item);
btrfs_set_item_offset(right, item, push_space);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
btrfs_mark_buffer_dirty(left);
if (right_nritems)
btrfs_mark_buffer_dirty(right);
ret = btrfs_update_ref(trans, root, right, left,
old_left_nritems, push_items);
BUG_ON(ret);
btrfs_item_key(right, &disk_key, 0);
wret = fixup_low_keys(trans, root, path, &disk_key, 1);
if (wret)
ret = wret;
/* then fixup the leaf pointer in the path */
if (path->slots[0] < push_items) {
path->slots[0] += old_left_nritems;
if (btrfs_header_nritems(path->nodes[0]) == 0)
clean_tree_block(trans, root, path->nodes[0]);
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = left;
path->slots[1] -= 1;
} else {
btrfs_tree_unlock(left);
free_extent_buffer(left);
path->slots[0] -= push_items;
}
BUG_ON(path->slots[0] < 0);
return ret;
out:
btrfs_tree_unlock(left);
free_extent_buffer(left);
return ret;
}
/*
* split the path's leaf in two, making sure there is at least data_size
* available for the resulting leaf level of the path.
*
* returns 0 if all went well and < 0 on failure.
*/
static 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 extent_buffer *l;
u32 nritems;
int mid;
int slot;
struct extent_buffer *right;
int space_needed = data_size + sizeof(struct btrfs_item);
int data_copy_size;
int rt_data_off;
int i;
int ret = 0;
int wret;
int double_split;
int num_doubles = 0;
struct btrfs_disk_key disk_key;
if (extend)
space_needed = data_size;
/* first try to make some room by pushing left and right */
if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
wret = push_leaf_right(trans, root, path, data_size, 0);
if (wret < 0) {
return wret;
}
if (wret) {
wret = push_leaf_left(trans, root, path, data_size, 0);
if (wret < 0)
return wret;
}
l = path->nodes[0];
/* did the pushes work? */
if (btrfs_leaf_free_space(root, l) >= space_needed)
return 0;
}
if (!path->nodes[1]) {
ret = insert_new_root(trans, root, path, 1);
if (ret)
return ret;
}
again:
double_split = 0;
l = path->nodes[0];
slot = path->slots[0];
nritems = btrfs_header_nritems(l);
mid = (nritems + 1)/ 2;
right = btrfs_alloc_free_block(trans, root, root->leafsize,
path->nodes[1]->start,
root->root_key.objectid,
trans->transid, 0, l->start, 0);
if (IS_ERR(right)) {
BUG_ON(1);
return PTR_ERR(right);
}
memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
btrfs_set_header_bytenr(right, right->start);
btrfs_set_header_generation(right, trans->transid);
btrfs_set_header_owner(right, root->root_key.objectid);
btrfs_set_header_level(right, 0);
write_extent_buffer(right, root->fs_info->fsid,
(unsigned long)btrfs_header_fsid(right),
BTRFS_FSID_SIZE);
write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
(unsigned long)btrfs_header_chunk_tree_uuid(right),
BTRFS_UUID_SIZE);
if (mid <= slot) {
if (nritems == 1 ||
leaf_space_used(l, mid, nritems - mid) + space_needed >
BTRFS_LEAF_DATA_SIZE(root)) {
if (slot >= nritems) {
btrfs_cpu_key_to_disk(&disk_key, ins_key);
btrfs_set_header_nritems(right, 0);
wret = insert_ptr(trans, root, path,
&disk_key, right->start,
path->slots[1] + 1, 1);
if (wret)
ret = wret;
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] = 0;
path->slots[1] += 1;
btrfs_mark_buffer_dirty(right);
return ret;
}
mid = slot;
if (mid != nritems &&
leaf_space_used(l, mid, nritems - mid) +
space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
double_split = 1;
}
}
} else {
if (leaf_space_used(l, 0, mid + 1) + space_needed >
BTRFS_LEAF_DATA_SIZE(root)) {
if (!extend && slot == 0) {
btrfs_cpu_key_to_disk(&disk_key, ins_key);
btrfs_set_header_nritems(right, 0);
wret = insert_ptr(trans, root, path,
&disk_key,
right->start,
path->slots[1], 1);
if (wret)
ret = wret;
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] = 0;
if (path->slots[1] == 0) {
wret = fixup_low_keys(trans, root,
path, &disk_key, 1);
if (wret)
ret = wret;
}
btrfs_mark_buffer_dirty(right);
return ret;
} else if (extend && slot == 0) {
mid = 1;
} else {
mid = slot;
if (mid != nritems &&
leaf_space_used(l, mid, nritems - mid) +
space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
double_split = 1;
}
}
}
}
nritems = nritems - mid;
btrfs_set_header_nritems(right, nritems);
data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
btrfs_item_nr_offset(mid),
nritems * sizeof(struct btrfs_item));
copy_extent_buffer(right, l,
btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
data_copy_size, btrfs_leaf_data(l) +
leaf_data_end(root, l), data_copy_size);
rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
btrfs_item_end_nr(l, mid);
for (i = 0; i < nritems; i++) {
struct btrfs_item *item = btrfs_item_nr(right, i);
u32 ioff;
if (!right->map_token) {
map_extent_buffer(right, (unsigned long)item,
sizeof(struct btrfs_item),
&right->map_token, &right->kaddr,
&right->map_start, &right->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(right, item);
btrfs_set_item_offset(right, item, ioff + rt_data_off);
}
if (right->map_token) {
unmap_extent_buffer(right, right->map_token, KM_USER1);
right->map_token = NULL;
}
btrfs_set_header_nritems(l, mid);
ret = 0;
btrfs_item_key(right, &disk_key, 0);
wret = insert_ptr(trans, root, path, &disk_key, right->start,
path->slots[1] + 1, 1);
if (wret)
ret = wret;
btrfs_mark_buffer_dirty(right);
btrfs_mark_buffer_dirty(l);
BUG_ON(path->slots[0] != slot);
ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
BUG_ON(ret);
if (mid <= slot) {
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
path->nodes[0] = right;
path->slots[0] -= mid;
path->slots[1] += 1;
} else {
btrfs_tree_unlock(right);
free_extent_buffer(right);
}
BUG_ON(path->slots[0] < 0);
if (double_split) {
BUG_ON(num_doubles != 0);
num_doubles++;
goto again;
}
return ret;
}
/*
* make the item pointed to by the path smaller. new_size indicates
* how small to make it, and from_end tells us if we just chop bytes
* off the end of the item or if we shift the item to chop bytes off
* the front.
*/
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u32 new_size, int from_end)
{
int ret = 0;
int slot;
int slot_orig;
struct extent_buffer *leaf;
struct btrfs_item *item;
u32 nritems;
unsigned int data_end;
unsigned int old_data_start;
unsigned int old_size;
unsigned int size_diff;
int i;
slot_orig = path->slots[0];
leaf = path->nodes[0];
slot = path->slots[0];
old_size = btrfs_item_size_nr(leaf, slot);
if (old_size == new_size)
return 0;
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(root, leaf);
old_data_start = btrfs_item_offset_nr(leaf, slot);
size_diff = old_size - new_size;
BUG_ON(slot < 0);
BUG_ON(slot >= nritems);
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff + size_diff);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
/* shift the data */
if (from_end) {
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + size_diff, btrfs_leaf_data(leaf) +
data_end, old_data_start + new_size - data_end);
} else {
struct btrfs_disk_key disk_key;
u64 offset;
btrfs_item_key(leaf, &disk_key, slot);
if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
unsigned long ptr;
struct btrfs_file_extent_item *fi;
fi = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
fi = (struct btrfs_file_extent_item *)(
(unsigned long)fi - size_diff);
if (btrfs_file_extent_type(leaf, fi) ==
BTRFS_FILE_EXTENT_INLINE) {
ptr = btrfs_item_ptr_offset(leaf, slot);
memmove_extent_buffer(leaf, ptr,
(unsigned long)fi,
offsetof(struct btrfs_file_extent_item,
disk_bytenr));
}
}
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end + size_diff, btrfs_leaf_data(leaf) +
data_end, old_data_start - data_end);
offset = btrfs_disk_key_offset(&disk_key);
btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
btrfs_set_item_key(leaf, &disk_key, slot);
if (slot == 0)
fixup_low_keys(trans, root, path, &disk_key, 1);
}
item = btrfs_item_nr(leaf, slot);
btrfs_set_item_size(leaf, item, new_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
return ret;
}
/*
* make the item pointed to by the path bigger, data_size is the new size.
*/
int btrfs_extend_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
u32 data_size)
{
int ret = 0;
int slot;
int slot_orig;
struct extent_buffer *leaf;
struct btrfs_item *item;
u32 nritems;
unsigned int data_end;
unsigned int old_data;
unsigned int old_size;
int i;
slot_orig = path->slots[0];
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(root, leaf);
if (btrfs_leaf_free_space(root, leaf) < data_size) {
btrfs_print_leaf(root, leaf);
BUG();
}
slot = path->slots[0];
old_data = btrfs_item_end_nr(leaf, slot);
BUG_ON(slot < 0);
if (slot >= nritems) {
btrfs_print_leaf(root, leaf);
printk("slot %d too large, nritems %d\n", slot, nritems);
BUG_ON(1);
}
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff - data_size);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
/* shift the data */
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end - data_size, btrfs_leaf_data(leaf) +
data_end, old_data - data_end);
data_end = old_data;
old_size = btrfs_item_size_nr(leaf, slot);
item = btrfs_item_nr(leaf, slot);
btrfs_set_item_size(leaf, item, old_size + data_size);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
return ret;
}
/*
* Given a key and some data, insert items into the tree.
* This does all the path init required, making room in the tree if needed.
*/
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *cpu_key, u32 *data_size,
int nr)
{
struct extent_buffer *leaf;
struct btrfs_item *item;
int ret = 0;
int slot;
int slot_orig;
int i;
u32 nritems;
u32 total_size = 0;
u32 total_data = 0;
unsigned int data_end;
struct btrfs_disk_key disk_key;
for (i = 0; i < nr; i++) {
total_data += data_size[i];
}
total_size = total_data + (nr * sizeof(struct btrfs_item));
ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
if (ret == 0)
return -EEXIST;
if (ret < 0)
goto out;
slot_orig = path->slots[0];
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
data_end = leaf_data_end(root, leaf);
if (btrfs_leaf_free_space(root, leaf) < 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 */
WARN_ON(leaf->map_token);
for (i = slot; i < nritems; i++) {
u32 ioff;
item = btrfs_item_nr(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff - total_data);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
/* shift the items */
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
btrfs_item_nr_offset(slot),
(nritems - slot) * sizeof(struct btrfs_item));
/* shift the data */
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
data_end - total_data, btrfs_leaf_data(leaf) +
data_end, old_data - data_end);
data_end = old_data;
}
/* setup the item for the new data */
for (i = 0; i < nr; i++) {
btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
btrfs_set_item_key(leaf, &disk_key, slot + i);
item = btrfs_item_nr(leaf, slot + i);
btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
data_end -= data_size[i];
btrfs_set_item_size(leaf, item, data_size[i]);
}
btrfs_set_header_nritems(leaf, nritems + nr);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
if (slot == 0) {
btrfs_cpu_key_to_disk(&disk_key, cpu_key);
ret = fixup_low_keys(trans, root, path, &disk_key, 1);
}
if (btrfs_leaf_free_space(root, leaf) < 0) {
btrfs_print_leaf(root, leaf);
BUG();
}
out:
return ret;
}
/*
* Given a key and some data, insert an item into the tree.
* This does all the path init required, making room in the tree if needed.
*/
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *cpu_key, void *data, u32
data_size)
{
int ret = 0;
struct btrfs_path *path;
struct extent_buffer *leaf;
unsigned long ptr;
path = btrfs_alloc_path();
BUG_ON(!path);
ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
if (!ret) {
leaf = path->nodes[0];
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, data, ptr, data_size);
btrfs_mark_buffer_dirty(leaf);
}
btrfs_free_path(path);
return ret;
}
/*
* delete the pointer from a given node.
*
* the tree should have been previously balanced so the deletion does not
* empty a node.
*/
static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot)
{
struct extent_buffer *parent = path->nodes[level];
u32 nritems;
int ret = 0;
int wret;
nritems = btrfs_header_nritems(parent);
if (slot != nritems -1) {
memmove_extent_buffer(parent,
btrfs_node_key_ptr_offset(slot),
btrfs_node_key_ptr_offset(slot + 1),
sizeof(struct btrfs_key_ptr) *
(nritems - slot - 1));
}
nritems--;
btrfs_set_header_nritems(parent, nritems);
if (nritems == 0 && parent == root->node) {
BUG_ON(btrfs_header_level(root->node) != 1);
/* just turn the root into a leaf and break */
btrfs_set_header_level(root->node, 0);
} else if (slot == 0) {
struct btrfs_disk_key disk_key;
btrfs_node_key(parent, &disk_key, 0);
wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
if (wret)
ret = wret;
}
btrfs_mark_buffer_dirty(parent);
return ret;
}
/*
* a helper function to delete the leaf pointed to by path->slots[1] and
* path->nodes[1]. bytenr is the node block pointer, but since the callers
* already know it, it is faster to have them pass it down than to
* read it out of the node again.
*
* 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.
*/
noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 bytenr)
{
int ret;
u64 root_gen = btrfs_header_generation(path->nodes[1]);
ret = del_ptr(trans, root, path, 1, path->slots[1]);
if (ret)
return ret;
ret = btrfs_free_extent(trans, root, bytenr,
btrfs_level_size(root, 0),
path->nodes[1]->start,
btrfs_header_owner(path->nodes[1]),
root_gen, 0, 1);
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(leaf, i);
if (!leaf->map_token) {
map_extent_buffer(leaf, (unsigned long)item,
sizeof(struct btrfs_item),
&leaf->map_token, &leaf->kaddr,
&leaf->map_start, &leaf->map_len,
KM_USER1);
}
ioff = btrfs_item_offset(leaf, item);
btrfs_set_item_offset(leaf, item, ioff + dsize);
}
if (leaf->map_token) {
unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
leaf->map_token = NULL;
}
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
btrfs_item_nr_offset(slot + nr),
sizeof(struct btrfs_item) *
(nritems - slot - nr));
}
btrfs_set_header_nritems(leaf, nritems - nr);
nritems -= nr;
/* delete the leaf if we've emptied it */
if (nritems == 0) {
if (leaf == root->node) {
btrfs_set_header_level(leaf, 0);
} else {
ret = btrfs_del_leaf(trans, root, path, leaf->start);
BUG_ON(ret);
}
} else {
int used = leaf_space_used(leaf, 0, nritems);
if (slot == 0) {
struct btrfs_disk_key disk_key;
btrfs_item_key(leaf, &disk_key, 0);
wret = fixup_low_keys(trans, root, path,
&disk_key, 1);
if (wret)
ret = wret;
}
/* delete the leaf if it is mostly empty */
if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
/* push_leaf_left fixes the path.
* make sure the path still points to our leaf
* for possible call to del_ptr below
*/
slot = path->slots[1];
extent_buffer_get(leaf);
wret = push_leaf_left(trans, root, path, 1, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
if (path->nodes[0] == leaf &&
btrfs_header_nritems(leaf)) {
wret = push_leaf_right(trans, root, path, 1, 1);
if (wret < 0 && wret != -ENOSPC)
ret = wret;
}
if (btrfs_header_nritems(leaf) == 0) {
path->slots[1] = slot;
ret = btrfs_del_leaf(trans, root, path, leaf->start);
BUG_ON(ret);
free_extent_buffer(leaf);
} else {
/* if we're still in the path, make sure
* we're dirty. Otherwise, one of the
* push_leaf functions must have already
* dirtied this buffer
*/
if (path->nodes[0] == leaf)
btrfs_mark_buffer_dirty(leaf);
free_extent_buffer(leaf);
}
} else {
btrfs_mark_buffer_dirty(leaf);
}
}
return ret;
}
/*
* search the tree again to find a leaf with lesser keys
* returns 0 if it found something or 1 if there are no lesser leaves.
* returns < 0 on io errors.
*
* This may release the path, and so you may lose any locks held at the
* time you call it.
*/
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
struct btrfs_key key;
struct btrfs_disk_key found_key;
int ret;
btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
if (key.offset > 0)
key.offset--;
else if (key.type > 0)
key.type--;
else if (key.objectid > 0)
key.objectid--;
else
return 1;
btrfs_release_path(root, path);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
return ret;
btrfs_item_key(path->nodes[0], &found_key, 0);
ret = comp_keys(&found_key, &key);
if (ret < 0)
return 0;
return 1;
}
/*
* A helper function to walk down the tree starting at min_key, and looking
* for nodes or leaves that are either in cache or have a minimum
* transaction id. This is used by the btree defrag code, and tree logging
*
* This does not cow, but it does stuff the starting key it finds back
* into min_key, so you can call btrfs_search_slot with cow=1 on the
* key and get a writable path.
*
* This does lock as it descends, and path->keep_locks should be set
* to 1 by the caller.
*
* This honors path->lowest_level to prevent descent past a given level
* of the tree.
*
* min_trans indicates the oldest transaction that you are interested
* in walking through. Any nodes or leaves older than min_trans are
* skipped over (without reading them).
*
* returns zero if something useful was found, < 0 on error and 1 if there
* was nothing in the tree that matched the search criteria.
*/
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
struct btrfs_key *max_key,
struct btrfs_path *path, int cache_only,
u64 min_trans)
{
struct extent_buffer *cur;
struct btrfs_key found_key;
int slot;
int sret;
u32 nritems;
int level;
int ret = 1;
again:
cur = btrfs_lock_root_node(root);
level = btrfs_header_level(cur);
WARN_ON(path->nodes[level]);
path->nodes[level] = cur;
path->locks[level] = 1;
if (btrfs_header_generation(cur) < min_trans) {
ret = 1;
goto out;
}
while(1) {
nritems = btrfs_header_nritems(cur);
level = btrfs_header_level(cur);
sret = bin_search(cur, min_key, level, &slot);
/* at the lowest level, we're done, setup the path and exit */
if (level == path->lowest_level) {
if (slot >= nritems)
goto find_next_key;
ret = 0;
path->slots[level] = slot;
btrfs_item_key_to_cpu(cur, &found_key, slot);
goto out;
}
if (sret && slot > 0)
slot--;
/*
* check this node pointer against the cache_only and
* min_trans parameters. If it isn't in cache or is too
* old, skip to the next one.
*/
while(slot < nritems) {
u64 blockptr;
u64 gen;
struct extent_buffer *tmp;
struct btrfs_disk_key disk_key;
blockptr = btrfs_node_blockptr(cur, slot);
gen = btrfs_node_ptr_generation(cur, slot);
if (gen < min_trans) {
slot++;
continue;
}
if (!cache_only)
break;
if (max_key) {
btrfs_node_key(cur, &disk_key, slot);
if (comp_keys(&disk_key, max_key) >= 0) {
ret = 1;
goto out;
}
}
tmp = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));
if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
free_extent_buffer(tmp);
break;
}
if (tmp)
free_extent_buffer(tmp);
slot++;
}
find_next_key:
/*
* we didn't find a candidate key in this node, walk forward
* and find another one
*/
if (slot >= nritems) {
path->slots[level] = slot;
sret = btrfs_find_next_key(root, path, min_key, level,
cache_only, min_trans);
if (sret == 0) {
btrfs_release_path(root, path);
goto again;
} else {
goto out;
}
}
/* save our key for returning back */
btrfs_node_key_to_cpu(cur, &found_key, slot);
path->slots[level] = slot;
if (level == path->lowest_level) {
ret = 0;
unlock_up(path, level, 1);
goto out;
}
cur = read_node_slot(root, cur, slot);
btrfs_tree_lock(cur);
path->locks[level - 1] = 1;
path->nodes[level - 1] = cur;
unlock_up(path, level, 1);
}
out:
if (ret == 0)
memcpy(min_key, &found_key, sizeof(found_key));
return ret;
}
/*
* this is similar to btrfs_next_leaf, but does not try to preserve
* and fixup the path. It looks for and returns the next key in the
* tree based on the current path and the cache_only and min_trans
* parameters.
*
* 0 is returned if another key is found, < 0 if there are any errors
* and 1 is returned if there are no higher keys in the tree
*
* path->keep_locks should be set to 1 on the search made before
* calling this function.
*/
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *key, int lowest_level,
int cache_only, u64 min_trans)
{
int level = lowest_level;
int slot;
struct extent_buffer *c;
while(level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
return 1;
slot = path->slots[level] + 1;
c = path->nodes[level];
next:
if (slot >= btrfs_header_nritems(c)) {
level++;
if (level == BTRFS_MAX_LEVEL) {
return 1;
}
continue;
}
if (level == 0)
btrfs_item_key_to_cpu(c, key, slot);
else {
u64 blockptr = btrfs_node_blockptr(c, slot);
u64 gen = btrfs_node_ptr_generation(c, slot);
if (cache_only) {
struct extent_buffer *cur;
cur = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));
if (!cur || !btrfs_buffer_uptodate(cur, gen)) {
slot++;
if (cur)
free_extent_buffer(cur);
goto next;
}
free_extent_buffer(cur);
}
if (gen < min_trans) {
slot++;
goto next;
}
btrfs_node_key_to_cpu(c, key, slot);
}
return 0;
}
return 1;
}
/*
* search the tree again to find a leaf with greater keys
* returns 0 if it found something or 1 if there are no greater leaves.
* returns < 0 on io errors.
*/
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
int slot;
int level = 1;
struct extent_buffer *c;
struct extent_buffer *next = NULL;
struct btrfs_key key;
u32 nritems;
int ret;
nritems = btrfs_header_nritems(path->nodes[0]);
if (nritems == 0) {
return 1;
}
btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
btrfs_release_path(root, path);
path->keep_locks = 1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
path->keep_locks = 0;
if (ret < 0)
return ret;
nritems = btrfs_header_nritems(path->nodes[0]);
/*
* by releasing the path above we dropped all our locks. A balance
* could have added more items next to the key that used to be
* at the very end of the block. So, check again here and
* advance the path if there are now more items available.
*/
if (nritems > 0 && path->slots[0] < nritems - 1) {
path->slots[0]++;
goto done;
}
while(level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
return 1;
slot = path->slots[level] + 1;
c = path->nodes[level];
if (slot >= btrfs_header_nritems(c)) {
level++;
if (level == BTRFS_MAX_LEVEL) {
return 1;
}
continue;
}
if (next) {
btrfs_tree_unlock(next);
free_extent_buffer(next);
}
if (level == 1 && (path->locks[1] || path->skip_locking) &&
path->reada)
reada_for_search(root, path, level, slot, 0);
next = read_node_slot(root, c, slot);
if (!path->skip_locking) {
WARN_ON(!btrfs_tree_locked(c));
btrfs_tree_lock(next);
}
break;
}
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
if (path->locks[level])
btrfs_tree_unlock(c);
free_extent_buffer(c);
path->nodes[level] = next;
path->slots[level] = 0;
if (!path->skip_locking)
path->locks[level] = 1;
if (!level)
break;
if (level == 1 && path->locks[1] && path->reada)
reada_for_search(root, path, level, slot, 0);
next = read_node_slot(root, next, 0);
if (!path->skip_locking) {
WARN_ON(!btrfs_tree_locked(path->nodes[level]));
btrfs_tree_lock(next);
}
}
done:
unlock_up(path, 0, 1);
return 0;
}
/*
* this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
* searching until it gets past min_objectid or finds an item of 'type'
*
* returns 0 if something is found, 1 if nothing was found and < 0 on error
*/
int btrfs_previous_item(struct btrfs_root *root,
struct btrfs_path *path, u64 min_objectid,
int type)
{
struct btrfs_key found_key;
struct extent_buffer *leaf;
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.type == type)
return 0;
if (found_key.objectid < min_objectid)
break;
if (found_key.objectid == min_objectid &&
found_key.type < type)
break;
}
return 1;
}
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