transaction.c 22.4 KB
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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.
 */

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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/writeback.h>
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#include <linux/pagemap.h>
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#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"

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static int total_trans = 0;
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extern struct kmem_cache *btrfs_trans_handle_cachep;
extern struct kmem_cache *btrfs_transaction_cachep;

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static struct workqueue_struct *trans_wq;

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#define BTRFS_ROOT_TRANS_TAG 0
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#define BTRFS_ROOT_DEFRAG_TAG 1
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static noinline void put_transaction(struct btrfs_transaction *transaction)
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{
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	WARN_ON(transaction->use_count == 0);
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	transaction->use_count--;
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	if (transaction->use_count == 0) {
		WARN_ON(total_trans == 0);
		total_trans--;
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		list_del_init(&transaction->list);
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		memset(transaction, 0, sizeof(*transaction));
		kmem_cache_free(btrfs_transaction_cachep, transaction);
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	}
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}

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static noinline int join_transaction(struct btrfs_root *root)
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{
	struct btrfs_transaction *cur_trans;
	cur_trans = root->fs_info->running_transaction;
	if (!cur_trans) {
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		cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
					     GFP_NOFS);
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		total_trans++;
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		BUG_ON(!cur_trans);
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		root->fs_info->generation++;
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		root->fs_info->running_transaction = cur_trans;
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		root->fs_info->last_alloc = 0;
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		root->fs_info->last_data_alloc = 0;
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		cur_trans->num_writers = 1;
		cur_trans->num_joined = 0;
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		cur_trans->transid = root->fs_info->generation;
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		init_waitqueue_head(&cur_trans->writer_wait);
		init_waitqueue_head(&cur_trans->commit_wait);
		cur_trans->in_commit = 0;
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		cur_trans->use_count = 1;
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		cur_trans->commit_done = 0;
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		cur_trans->start_time = get_seconds();
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		INIT_LIST_HEAD(&cur_trans->pending_snapshots);
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		list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
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		btrfs_ordered_inode_tree_init(&cur_trans->ordered_inode_tree);
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		extent_io_tree_init(&cur_trans->dirty_pages,
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				     root->fs_info->btree_inode->i_mapping,
				     GFP_NOFS);
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	} else {
		cur_trans->num_writers++;
		cur_trans->num_joined++;
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	}
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	return 0;
}

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static noinline int record_root_in_trans(struct btrfs_root *root)
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{
	u64 running_trans_id = root->fs_info->running_transaction->transid;
	if (root->ref_cows && root->last_trans < running_trans_id) {
		WARN_ON(root == root->fs_info->extent_root);
		if (root->root_item.refs != 0) {
			radix_tree_tag_set(&root->fs_info->fs_roots_radix,
				   (unsigned long)root->root_key.objectid,
				   BTRFS_ROOT_TRANS_TAG);
			radix_tree_tag_set(&root->fs_info->fs_roots_radix,
				   (unsigned long)root->root_key.objectid,
				   BTRFS_ROOT_DEFRAG_TAG);
			root->commit_root = root->node;
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			extent_buffer_get(root->node);
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		} else {
			WARN_ON(1);
		}
		root->last_trans = running_trans_id;
	}
	return 0;
}

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struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
						   int num_blocks)
{
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	struct btrfs_trans_handle *h =
		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
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	int ret;

	mutex_lock(&root->fs_info->trans_mutex);
	ret = join_transaction(root);
	BUG_ON(ret);
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	record_root_in_trans(root);
	h->transid = root->fs_info->running_transaction->transid;
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	h->transaction = root->fs_info->running_transaction;
	h->blocks_reserved = num_blocks;
	h->blocks_used = 0;
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	h->block_group = NULL;
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	h->alloc_exclude_nr = 0;
	h->alloc_exclude_start = 0;
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	root->fs_info->running_transaction->use_count++;
	mutex_unlock(&root->fs_info->trans_mutex);
	return h;
}

int btrfs_end_transaction(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root)
{
	struct btrfs_transaction *cur_trans;
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	mutex_lock(&root->fs_info->trans_mutex);
	cur_trans = root->fs_info->running_transaction;
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	WARN_ON(cur_trans != trans->transaction);
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	WARN_ON(cur_trans->num_writers < 1);
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	cur_trans->num_writers--;
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	if (waitqueue_active(&cur_trans->writer_wait))
		wake_up(&cur_trans->writer_wait);
	put_transaction(cur_trans);
	mutex_unlock(&root->fs_info->trans_mutex);
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	memset(trans, 0, sizeof(*trans));
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	kmem_cache_free(btrfs_trans_handle_cachep, trans);
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	return 0;
}


int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
				     struct btrfs_root *root)
{
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	int ret;
	int err;
	int werr = 0;
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	struct extent_io_tree *dirty_pages;
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	struct page *page;
	struct inode *btree_inode = root->fs_info->btree_inode;
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	u64 start;
	u64 end;
	unsigned long index;
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	if (!trans || !trans->transaction) {
		return filemap_write_and_wait(btree_inode->i_mapping);
	}
	dirty_pages = &trans->transaction->dirty_pages;
	while(1) {
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		ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
					    EXTENT_DIRTY);
		if (ret)
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			break;
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		clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
		while(start <= end) {
			index = start >> PAGE_CACHE_SHIFT;
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			start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
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			page = find_lock_page(btree_inode->i_mapping, index);
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			if (!page)
				continue;
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			if (PageWriteback(page)) {
				if (PageDirty(page))
					wait_on_page_writeback(page);
				else {
					unlock_page(page);
					page_cache_release(page);
					continue;
				}
			}
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			err = write_one_page(page, 0);
			if (err)
				werr = err;
			page_cache_release(page);
		}
	}
	err = filemap_fdatawait(btree_inode->i_mapping);
	if (err)
		werr = err;
	return werr;
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}

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static int update_cowonly_root(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root)
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{
	int ret;
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	u64 old_root_bytenr;
	struct btrfs_root *tree_root = root->fs_info->tree_root;
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	btrfs_write_dirty_block_groups(trans, root);
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	while(1) {
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		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
		if (old_root_bytenr == root->node->start)
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			break;
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		btrfs_set_root_bytenr(&root->root_item,
				       root->node->start);
		btrfs_set_root_level(&root->root_item,
				     btrfs_header_level(root->node));
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		ret = btrfs_update_root(trans, tree_root,
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					&root->root_key,
					&root->root_item);
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		BUG_ON(ret);
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		btrfs_write_dirty_block_groups(trans, root);
	}
	return 0;
}

int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
			    struct btrfs_root *root)
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct list_head *next;

	while(!list_empty(&fs_info->dirty_cowonly_roots)) {
		next = fs_info->dirty_cowonly_roots.next;
		list_del_init(next);
		root = list_entry(next, struct btrfs_root, dirty_list);
		update_cowonly_root(trans, root);
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	}
	return 0;
}

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static noinline int wait_for_commit(struct btrfs_root *root,
				    struct btrfs_transaction *commit)
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{
	DEFINE_WAIT(wait);
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	mutex_lock(&root->fs_info->trans_mutex);
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	while(!commit->commit_done) {
		prepare_to_wait(&commit->commit_wait, &wait,
				TASK_UNINTERRUPTIBLE);
		if (commit->commit_done)
			break;
		mutex_unlock(&root->fs_info->trans_mutex);
		schedule();
		mutex_lock(&root->fs_info->trans_mutex);
	}
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	mutex_unlock(&root->fs_info->trans_mutex);
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	finish_wait(&commit->commit_wait, &wait);
	return 0;
}

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struct dirty_root {
	struct list_head list;
	struct btrfs_root *root;
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	struct btrfs_root *latest_root;
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};

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int btrfs_add_dead_root(struct btrfs_root *root,
			struct btrfs_root *latest,
			struct list_head *dead_list)
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{
	struct dirty_root *dirty;

	dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
	if (!dirty)
		return -ENOMEM;
	dirty->root = root;
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	dirty->latest_root = latest;
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	list_add(&dirty->list, dead_list);
	return 0;
}

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static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
				    struct radix_tree_root *radix,
				    struct list_head *list)
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{
	struct dirty_root *dirty;
	struct btrfs_root *gang[8];
	struct btrfs_root *root;
	int i;
	int ret;
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	int err = 0;
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	u32 refs;
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	while(1) {
		ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
						 ARRAY_SIZE(gang),
						 BTRFS_ROOT_TRANS_TAG);
		if (ret == 0)
			break;
		for (i = 0; i < ret; i++) {
			root = gang[i];
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			radix_tree_tag_clear(radix,
				     (unsigned long)root->root_key.objectid,
				     BTRFS_ROOT_TRANS_TAG);
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			if (root->commit_root == root->node) {
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				WARN_ON(root->node->start !=
					btrfs_root_bytenr(&root->root_item));
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				free_extent_buffer(root->commit_root);
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				root->commit_root = NULL;
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				/* make sure to update the root on disk
				 * so we get any updates to the block used
				 * counts
				 */
				err = btrfs_update_root(trans,
						root->fs_info->tree_root,
						&root->root_key,
						&root->root_item);
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				continue;
			}
			dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
			BUG_ON(!dirty);
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			dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
			BUG_ON(!dirty->root);

			memset(&root->root_item.drop_progress, 0,
			       sizeof(struct btrfs_disk_key));
			root->root_item.drop_level = 0;

			memcpy(dirty->root, root, sizeof(*root));
			dirty->root->node = root->commit_root;
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			dirty->latest_root = root;
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			root->commit_root = NULL;
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			root->root_key.offset = root->fs_info->generation;
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			btrfs_set_root_bytenr(&root->root_item,
					      root->node->start);
			btrfs_set_root_level(&root->root_item,
					     btrfs_header_level(root->node));
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			err = btrfs_insert_root(trans, root->fs_info->tree_root,
						&root->root_key,
						&root->root_item);
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			if (err)
				break;
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			refs = btrfs_root_refs(&dirty->root->root_item);
			btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
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			err = btrfs_update_root(trans, root->fs_info->tree_root,
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						&dirty->root->root_key,
						&dirty->root->root_item);
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			BUG_ON(err);
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			if (refs == 1) {
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				list_add(&dirty->list, list);
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			} else {
				WARN_ON(1);
				kfree(dirty->root);
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				kfree(dirty);
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			}
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		}
	}
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	return err;
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}

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int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
{
	struct btrfs_fs_info *info = root->fs_info;
	int ret;
	struct btrfs_trans_handle *trans;
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	unsigned long nr;
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	if (root->defrag_running)
		return 0;
	trans = btrfs_start_transaction(root, 1);
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	while (1) {
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		root->defrag_running = 1;
		ret = btrfs_defrag_leaves(trans, root, cacheonly);
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		nr = trans->blocks_used;
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		btrfs_end_transaction(trans, root);
		mutex_unlock(&info->fs_mutex);
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		btrfs_btree_balance_dirty(info->tree_root, nr);
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		cond_resched();

		mutex_lock(&info->fs_mutex);
		trans = btrfs_start_transaction(root, 1);
		if (ret != -EAGAIN)
			break;
	}
	root->defrag_running = 0;
	radix_tree_tag_clear(&info->fs_roots_radix,
		     (unsigned long)root->root_key.objectid,
		     BTRFS_ROOT_DEFRAG_TAG);
	btrfs_end_transaction(trans, root);
	return 0;
}

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int btrfs_defrag_dirty_roots(struct btrfs_fs_info *info)
{
	struct btrfs_root *gang[1];
	struct btrfs_root *root;
	int i;
	int ret;
	int err = 0;
	u64 last = 0;

	while(1) {
		ret = radix_tree_gang_lookup_tag(&info->fs_roots_radix,
						 (void **)gang, last,
						 ARRAY_SIZE(gang),
						 BTRFS_ROOT_DEFRAG_TAG);
		if (ret == 0)
			break;
		for (i = 0; i < ret; i++) {
			root = gang[i];
			last = root->root_key.objectid + 1;
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			btrfs_defrag_root(root, 1);
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		}
	}
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	btrfs_defrag_root(info->extent_root, 1);
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	return err;
}

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static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
				     struct list_head *list)
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{
	struct dirty_root *dirty;
	struct btrfs_trans_handle *trans;
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	unsigned long nr;
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	u64 num_bytes;
	u64 bytes_used;
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	int ret = 0;
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	int err;

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	while(!list_empty(list)) {
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		struct btrfs_root *root;

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		mutex_lock(&tree_root->fs_info->fs_mutex);
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		dirty = list_entry(list->next, struct dirty_root, list);
		list_del_init(&dirty->list);
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		num_bytes = btrfs_root_used(&dirty->root->root_item);
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		root = dirty->latest_root;
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		root->fs_info->throttles++;
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		while(1) {
			trans = btrfs_start_transaction(tree_root, 1);
			ret = btrfs_drop_snapshot(trans, dirty->root);
			if (ret != -EAGAIN) {
				break;
			}
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			err = btrfs_update_root(trans,
					tree_root,
					&dirty->root->root_key,
					&dirty->root->root_item);
			if (err)
				ret = err;
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			nr = trans->blocks_used;
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			ret = btrfs_end_transaction(trans, tree_root);
			BUG_ON(ret);
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			mutex_unlock(&tree_root->fs_info->fs_mutex);
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			btrfs_btree_balance_dirty(tree_root, nr);
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			cond_resched();
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			mutex_lock(&tree_root->fs_info->fs_mutex);
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		}
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		BUG_ON(ret);
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		root->fs_info->throttles--;
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		num_bytes -= btrfs_root_used(&dirty->root->root_item);
		bytes_used = btrfs_root_used(&root->root_item);
		if (num_bytes) {
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			record_root_in_trans(root);
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			btrfs_set_root_used(&root->root_item,
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					    bytes_used - num_bytes);
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		}
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		ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
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		if (ret) {
			BUG();
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			break;
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		}
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		nr = trans->blocks_used;
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		ret = btrfs_end_transaction(trans, tree_root);
		BUG_ON(ret);
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		free_extent_buffer(dirty->root->node);
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		kfree(dirty->root);
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		kfree(dirty);
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		mutex_unlock(&tree_root->fs_info->fs_mutex);
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		btrfs_btree_balance_dirty(tree_root, nr);
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		cond_resched();
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	}
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	return ret;
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}

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int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
				struct btrfs_root *root)
{
	struct btrfs_transaction *cur_trans = trans->transaction;
	struct inode *inode;
	u64 root_objectid = 0;
	u64 objectid = 0;
	int ret;

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	root->fs_info->throttles++;
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	while(1) {
		ret = btrfs_find_first_ordered_inode(
				&cur_trans->ordered_inode_tree,
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				&root_objectid, &objectid, &inode);
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		if (!ret)
			break;

		mutex_unlock(&root->fs_info->trans_mutex);
		mutex_unlock(&root->fs_info->fs_mutex);
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		if (S_ISREG(inode->i_mode))
			filemap_fdatawrite(inode->i_mapping);
		iput(inode);

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		mutex_lock(&root->fs_info->fs_mutex);
		mutex_lock(&root->fs_info->trans_mutex);
	}
	while(1) {
		root_objectid = 0;
		objectid = 0;
		ret = btrfs_find_del_first_ordered_inode(
				&cur_trans->ordered_inode_tree,
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				&root_objectid, &objectid, &inode);
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		if (!ret)
			break;
		mutex_unlock(&root->fs_info->trans_mutex);
		mutex_unlock(&root->fs_info->fs_mutex);
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		if (S_ISREG(inode->i_mode))
			filemap_write_and_wait(inode->i_mapping);
		atomic_dec(&inode->i_count);
		iput(inode);

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		mutex_lock(&root->fs_info->fs_mutex);
		mutex_lock(&root->fs_info->trans_mutex);
	}
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	root->fs_info->throttles--;
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	return 0;
}

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static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
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				   struct btrfs_fs_info *fs_info,
				   struct btrfs_pending_snapshot *pending)
{
	struct btrfs_key key;
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	struct btrfs_root_item *new_root_item;
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	struct btrfs_root *tree_root = fs_info->tree_root;
	struct btrfs_root *root = pending->root;
	struct extent_buffer *tmp;
	int ret;
	u64 objectid;

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	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
	if (!new_root_item) {
		ret = -ENOMEM;
		goto fail;
	}
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	ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
	if (ret)
		goto fail;

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	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
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	key.objectid = objectid;
	key.offset = 1;
	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);

	extent_buffer_get(root->node);
	btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
	free_extent_buffer(tmp);

	btrfs_copy_root(trans, root, root->node, &tmp, objectid);

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	btrfs_set_root_bytenr(new_root_item, tmp->start);
	btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
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	ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
581
				new_root_item);
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	free_extent_buffer(tmp);
	if (ret)
		goto fail;

	/*
	 * insert the directory item
	 */
	key.offset = (u64)-1;
	ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
				    pending->name, strlen(pending->name),
				    root->fs_info->sb->s_root->d_inode->i_ino,
				    &key, BTRFS_FT_DIR);

	if (ret)
		goto fail;

	ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
			     pending->name, strlen(pending->name), objectid,
			     root->fs_info->sb->s_root->d_inode->i_ino);
fail:
602
	kfree(new_root_item);
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	return ret;
}

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static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
					     struct btrfs_fs_info *fs_info)
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{
	struct btrfs_pending_snapshot *pending;
	struct list_head *head = &trans->transaction->pending_snapshots;
	int ret;

	while(!list_empty(head)) {
		pending = list_entry(head->next,
				     struct btrfs_pending_snapshot, list);
		ret = create_pending_snapshot(trans, fs_info, pending);
		BUG_ON(ret);
		list_del(&pending->list);
		kfree(pending->name);
		kfree(pending);
	}
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	return 0;
}

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int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root)
{
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	unsigned long joined = 0;
	unsigned long timeout = 1;
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	struct btrfs_transaction *cur_trans;
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	struct btrfs_transaction *prev_trans = NULL;
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	struct btrfs_root *chunk_root = root->fs_info->chunk_root;
633
	struct list_head dirty_fs_roots;
634
	struct extent_io_tree *pinned_copy;
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	DEFINE_WAIT(wait);
636
	int ret;
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	INIT_LIST_HEAD(&dirty_fs_roots);
639

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	mutex_lock(&root->fs_info->trans_mutex);
	if (trans->transaction->in_commit) {
		cur_trans = trans->transaction;
		trans->transaction->use_count++;
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		mutex_unlock(&root->fs_info->trans_mutex);
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		btrfs_end_transaction(trans, root);
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		mutex_unlock(&root->fs_info->fs_mutex);
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		ret = wait_for_commit(root, cur_trans);
		BUG_ON(ret);
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		mutex_lock(&root->fs_info->trans_mutex);
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		put_transaction(cur_trans);
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		mutex_unlock(&root->fs_info->trans_mutex);

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		mutex_lock(&root->fs_info->fs_mutex);
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		return 0;
	}
658 659 660 661 662

	pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
	if (!pinned_copy)
		return -ENOMEM;

663
	extent_io_tree_init(pinned_copy,
664 665
			     root->fs_info->btree_inode->i_mapping, GFP_NOFS);

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	trans->transaction->in_commit = 1;
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	cur_trans = trans->transaction;
	if (cur_trans->list.prev != &root->fs_info->trans_list) {
		prev_trans = list_entry(cur_trans->list.prev,
					struct btrfs_transaction, list);
		if (!prev_trans->commit_done) {
			prev_trans->use_count++;
			mutex_unlock(&root->fs_info->fs_mutex);
			mutex_unlock(&root->fs_info->trans_mutex);

			wait_for_commit(root, prev_trans);

			mutex_lock(&root->fs_info->fs_mutex);
			mutex_lock(&root->fs_info->trans_mutex);
680
			put_transaction(prev_trans);
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		}
	}
683 684 685

	do {
		joined = cur_trans->num_joined;
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		WARN_ON(cur_trans != trans->transaction);
687
		prepare_to_wait(&cur_trans->writer_wait, &wait,
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				TASK_UNINTERRUPTIBLE);
689 690 691 692 693 694

		if (cur_trans->num_writers > 1)
			timeout = MAX_SCHEDULE_TIMEOUT;
		else
			timeout = 1;

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		mutex_unlock(&root->fs_info->fs_mutex);
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		mutex_unlock(&root->fs_info->trans_mutex);
697 698 699

		schedule_timeout(timeout);

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		mutex_lock(&root->fs_info->fs_mutex);
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		mutex_lock(&root->fs_info->trans_mutex);
702
		finish_wait(&cur_trans->writer_wait, &wait);
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		ret = btrfs_write_ordered_inodes(trans, root);

705 706 707
	} while (cur_trans->num_writers > 1 ||
		 (cur_trans->num_joined != joined));

708 709 710
	ret = create_pending_snapshots(trans, root->fs_info);
	BUG_ON(ret);

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	WARN_ON(cur_trans != trans->transaction);
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713 714 715 716
	ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
			      &dirty_fs_roots);
	BUG_ON(ret);

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	ret = btrfs_commit_tree_roots(trans, root);
	BUG_ON(ret);
719

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	cur_trans = root->fs_info->running_transaction;
721
	spin_lock(&root->fs_info->new_trans_lock);
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	root->fs_info->running_transaction = NULL;
723
	spin_unlock(&root->fs_info->new_trans_lock);
724 725 726
	btrfs_set_super_generation(&root->fs_info->super_copy,
				   cur_trans->transid);
	btrfs_set_super_root(&root->fs_info->super_copy,
727 728 729
			     root->fs_info->tree_root->node->start);
	btrfs_set_super_root_level(&root->fs_info->super_copy,
			   btrfs_header_level(root->fs_info->tree_root->node));
730

731 732 733 734
	btrfs_set_super_chunk_root(&root->fs_info->super_copy,
				   chunk_root->node->start);
	btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
					 btrfs_header_level(chunk_root->node));
735 736 737
	write_extent_buffer(root->fs_info->sb_buffer,
			    &root->fs_info->super_copy, 0,
			    sizeof(root->fs_info->super_copy));
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739
	btrfs_copy_pinned(root, pinned_copy);
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	mutex_unlock(&root->fs_info->trans_mutex);
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	mutex_unlock(&root->fs_info->fs_mutex);
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	ret = btrfs_write_and_wait_transaction(trans, root);
	BUG_ON(ret);
	write_ctree_super(trans, root);
746

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	mutex_lock(&root->fs_info->fs_mutex);
748
	btrfs_finish_extent_commit(trans, root, pinned_copy);
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	mutex_lock(&root->fs_info->trans_mutex);
750 751 752

	kfree(pinned_copy);

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	cur_trans->commit_done = 1;
754
	root->fs_info->last_trans_committed = cur_trans->transid;
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	wake_up(&cur_trans->commit_wait);
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	put_transaction(cur_trans);
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	put_transaction(cur_trans);
758

759 760 761 762
	if (root->fs_info->closing)
		list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
	else
		list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
763

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	mutex_unlock(&root->fs_info->trans_mutex);
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	kmem_cache_free(btrfs_trans_handle_cachep, trans);
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767 768 769 770 771
	if (root->fs_info->closing) {
		mutex_unlock(&root->fs_info->fs_mutex);
		drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
		mutex_lock(&root->fs_info->fs_mutex);
	}
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	return ret;
}

775 776 777 778 779 780 781 782 783 784 785 786 787 788
int btrfs_clean_old_snapshots(struct btrfs_root *root)
{
	struct list_head dirty_roots;
	INIT_LIST_HEAD(&dirty_roots);

	mutex_lock(&root->fs_info->trans_mutex);
	list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
	mutex_unlock(&root->fs_info->trans_mutex);

	if (!list_empty(&dirty_roots)) {
		drop_dirty_roots(root, &dirty_roots);
	}
	return 0;
}
789 790 791
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
void btrfs_transaction_cleaner(void *p)
#else
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void btrfs_transaction_cleaner(struct work_struct *work)
793
#endif
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{
795 796 797
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
	struct btrfs_fs_info *fs_info = p;
#else
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	struct btrfs_fs_info *fs_info = container_of(work,
						     struct btrfs_fs_info,
						     trans_work.work);

802
#endif
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	struct btrfs_root *root = fs_info->tree_root;
	struct btrfs_transaction *cur;
	struct btrfs_trans_handle *trans;
	unsigned long now;
	unsigned long delay = HZ * 30;
	int ret;

	mutex_lock(&root->fs_info->fs_mutex);
	mutex_lock(&root->fs_info->trans_mutex);
	cur = root->fs_info->running_transaction;
	if (!cur) {
		mutex_unlock(&root->fs_info->trans_mutex);
		goto out;
	}
	now = get_seconds();
	if (now < cur->start_time || now - cur->start_time < 30) {
		mutex_unlock(&root->fs_info->trans_mutex);
		delay = HZ * 5;
		goto out;
	}
	mutex_unlock(&root->fs_info->trans_mutex);
824
	btrfs_defrag_dirty_roots(root->fs_info);
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	trans = btrfs_start_transaction(root, 1);
	ret = btrfs_commit_transaction(trans, root);
out:
	mutex_unlock(&root->fs_info->fs_mutex);
829
	btrfs_clean_old_snapshots(root);
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	btrfs_transaction_queue_work(root, delay);
}

void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
{
	queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
}

void btrfs_transaction_flush_work(struct btrfs_root *root)
{
	cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
	flush_workqueue(trans_wq);
}

void __init btrfs_init_transaction_sys(void)
{
	trans_wq = create_workqueue("btrfs");
}

849
void btrfs_exit_transaction_sys(void)
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{
	destroy_workqueue(trans_wq);
}