[linux-2.6-block.git] / fs / btrfs / transaction.c

#include <linux/module.h>
#include <linux/fs.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"

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

#define BTRFS_ROOT_TRANS_TAG 0

#define TRANS_MAGIC 0xE1E10E
static void put_transaction(struct btrfs_transaction *transaction)
{
	WARN_ON(transaction->use_count == 0);
	transaction->use_count--;
	WARN_ON(transaction->magic != TRANS_MAGIC);
	if (transaction->use_count == 0) {
		WARN_ON(total_trans == 0);
		total_trans--;
		list_del_init(&transaction->list);
		memset(transaction, 0, sizeof(*transaction));
		kmem_cache_free(btrfs_transaction_cachep, transaction);
	}
}

static int join_transaction(struct btrfs_root *root)
{
	struct btrfs_transaction *cur_trans;
	cur_trans = root->fs_info->running_transaction;
	if (!cur_trans) {
		cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
					     GFP_NOFS);
		total_trans++;
		BUG_ON(!cur_trans);
		root->fs_info->generation++;
		root->fs_info->running_transaction = cur_trans;
		cur_trans->num_writers = 0;
		cur_trans->transid = root->fs_info->generation;
		init_waitqueue_head(&cur_trans->writer_wait);
		init_waitqueue_head(&cur_trans->commit_wait);
		cur_trans->magic = TRANS_MAGIC;
		cur_trans->in_commit = 0;
		cur_trans->use_count = 1;
		cur_trans->commit_done = 0;
		list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
		init_bit_radix(&cur_trans->dirty_pages);
	}
	cur_trans->num_writers++;
	return 0;
}

struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
						   int num_blocks)
{
	struct btrfs_trans_handle *h =
		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
	int ret;
	u64 running_trans_id;

	mutex_lock(&root->fs_info->trans_mutex);
	ret = join_transaction(root);
	BUG_ON(ret);
	running_trans_id = root->fs_info->running_transaction->transid;

	if (root != root->fs_info->tree_root && root->last_trans <
	    running_trans_id) {
		radix_tree_tag_set(&root->fs_info->fs_roots_radix,
				   (unsigned long)root->root_key.objectid,
				   BTRFS_ROOT_TRANS_TAG);
		root->commit_root = root->node;
		get_bh(root->node);
	}
	root->last_trans = running_trans_id;
	h->transid = running_trans_id;
	h->transaction = root->fs_info->running_transaction;
	h->blocks_reserved = num_blocks;
	h->blocks_used = 0;
	root->fs_info->running_transaction->use_count++;
	mutex_unlock(&root->fs_info->trans_mutex);
	h->magic = h->magic2 = TRANS_MAGIC;
	return h;
}

int btrfs_end_transaction(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root)
{
	struct btrfs_transaction *cur_trans;

	WARN_ON(trans->magic != TRANS_MAGIC);
	WARN_ON(trans->magic2 != TRANS_MAGIC);
	mutex_lock(&root->fs_info->trans_mutex);
	cur_trans = root->fs_info->running_transaction;
	WARN_ON(cur_trans->num_writers < 1);
	if (waitqueue_active(&cur_trans->writer_wait))
		wake_up(&cur_trans->writer_wait);
	cur_trans->num_writers--;
	put_transaction(cur_trans);
	mutex_unlock(&root->fs_info->trans_mutex);
	memset(trans, 0, sizeof(*trans));
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
	return 0;
}


int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
				     struct btrfs_root *root)
{
	unsigned long gang[16];
	int ret;
	int i;
	int err;
	int werr = 0;
	struct page *page;
	struct radix_tree_root *dirty_pages;
	struct inode *btree_inode = root->fs_info->btree_inode;

	if (!trans || !trans->transaction) {
		return filemap_write_and_wait(btree_inode->i_mapping);
	}
	dirty_pages = &trans->transaction->dirty_pages;
	while(1) {
		ret = find_first_radix_bit(dirty_pages, gang, ARRAY_SIZE(gang));
		if (!ret)
			break;
		for (i = 0; i < ret; i++) {
			/* FIXME EIO */
			clear_radix_bit(dirty_pages, gang[i]);
			page = find_lock_page(btree_inode->i_mapping,
					      gang[i]);
			if (!page)
				continue;
			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;
}

int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
			    struct btrfs_root *root)
{
	int ret;
	u64 old_extent_block;
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct btrfs_root *tree_root = fs_info->tree_root;
	struct btrfs_root *extent_root = fs_info->extent_root;
	struct btrfs_root *dev_root = fs_info->dev_root;

	if (btrfs_super_device_root(fs_info->disk_super) !=
	    bh_blocknr(dev_root->node)) {
		btrfs_set_super_device_root(fs_info->disk_super,
					    bh_blocknr(dev_root->node));
	}
	btrfs_write_dirty_block_groups(trans, extent_root);
	while(1) {
		old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
		if (old_extent_block == bh_blocknr(extent_root->node))
			break;
		btrfs_set_root_blocknr(&extent_root->root_item,
				       bh_blocknr(extent_root->node));
		ret = btrfs_update_root(trans, tree_root,
					&extent_root->root_key,
					&extent_root->root_item);
		BUG_ON(ret);
		btrfs_write_dirty_block_groups(trans, extent_root);
	}
	return 0;
}

static int wait_for_commit(struct btrfs_root *root,
			   struct btrfs_transaction *commit)
{
	DEFINE_WAIT(wait);
	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);
	}
	finish_wait(&commit->commit_wait, &wait);
	return 0;
}

struct dirty_root {
	struct list_head list;
	struct btrfs_key snap_key;
	struct buffer_head *commit_root;
	struct btrfs_root *root;
};

int add_dirty_roots(struct btrfs_trans_handle *trans,
		    struct radix_tree_root *radix, struct list_head *list)
{
	struct dirty_root *dirty;
	struct btrfs_root *gang[8];
	struct btrfs_root *root;
	int i;
	int ret;
	int err;
	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];
			radix_tree_tag_clear(radix,
				     (unsigned long)root->root_key.objectid,
				     BTRFS_ROOT_TRANS_TAG);
			if (root->commit_root == root->node) {
				WARN_ON(bh_blocknr(root->node) !=
					btrfs_root_blocknr(&root->root_item));
				brelse(root->commit_root);
				root->commit_root = NULL;
				continue;
			}
			dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
			BUG_ON(!dirty);
			memcpy(&dirty->snap_key, &root->root_key,
			       sizeof(root->root_key));
			dirty->commit_root = root->commit_root;
			root->commit_root = NULL;
			dirty->root = root;
			root->root_key.offset = root->fs_info->generation;
			btrfs_set_root_blocknr(&root->root_item,
					       bh_blocknr(root->node));
			err = btrfs_insert_root(trans, root->fs_info->tree_root,
						&root->root_key,
						&root->root_item);
			BUG_ON(err);
			list_add(&dirty->list, list);
		}
	}
	return 0;
}

int drop_dirty_roots(struct btrfs_root *tree_root, struct list_head *list)
{
	struct dirty_root *dirty;
	struct btrfs_trans_handle *trans;
	int ret;

	while(!list_empty(list)) {
		dirty = list_entry(list->next, struct dirty_root, list);
		list_del_init(&dirty->list);
		trans = btrfs_start_transaction(tree_root, 1);
		ret = btrfs_drop_snapshot(trans, dirty->root,
					  dirty->commit_root);
		BUG_ON(ret);

		ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
		BUG_ON(ret);
		ret = btrfs_end_transaction(trans, tree_root);
		BUG_ON(ret);
		kfree(dirty);
	}
	return 0;
}

int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root)
{
	int ret = 0;
	struct btrfs_transaction *cur_trans;
	struct btrfs_transaction *prev_trans = NULL;
	struct list_head dirty_fs_roots;
	DEFINE_WAIT(wait);

	INIT_LIST_HEAD(&dirty_fs_roots);

	mutex_lock(&root->fs_info->trans_mutex);
	if (trans->transaction->in_commit) {
		cur_trans = trans->transaction;
		trans->transaction->use_count++;
		btrfs_end_transaction(trans, root);
		ret = wait_for_commit(root, cur_trans);
		BUG_ON(ret);
		put_transaction(cur_trans);
		mutex_unlock(&root->fs_info->trans_mutex);
		return 0;
	}
	cur_trans = trans->transaction;
	trans->transaction->in_commit = 1;
	while (trans->transaction->num_writers > 1) {
		WARN_ON(cur_trans != trans->transaction);
		prepare_to_wait(&trans->transaction->writer_wait, &wait,
				TASK_UNINTERRUPTIBLE);
		if (trans->transaction->num_writers <= 1)
			break;
		mutex_unlock(&root->fs_info->trans_mutex);
		schedule();
		mutex_lock(&root->fs_info->trans_mutex);
		finish_wait(&trans->transaction->writer_wait, &wait);
	}
	finish_wait(&trans->transaction->writer_wait, &wait);
	WARN_ON(cur_trans != trans->transaction);
	add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
	ret = btrfs_commit_tree_roots(trans, root);
	BUG_ON(ret);
	cur_trans = root->fs_info->running_transaction;
	root->fs_info->running_transaction = NULL;
	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 = NULL;
		else
			prev_trans->use_count++;
	}
	mutex_unlock(&root->fs_info->trans_mutex);
	mutex_unlock(&root->fs_info->fs_mutex);
	ret = btrfs_write_and_wait_transaction(trans, root);
	if (prev_trans) {
		mutex_lock(&root->fs_info->trans_mutex);
		wait_for_commit(root, prev_trans);
		put_transaction(prev_trans);
		mutex_unlock(&root->fs_info->trans_mutex);
	}
	btrfs_set_super_generation(root->fs_info->disk_super,
				   cur_trans->transid);
	BUG_ON(ret);
	write_ctree_super(trans, root);

	mutex_lock(&root->fs_info->fs_mutex);
	btrfs_finish_extent_commit(trans, root);
	mutex_lock(&root->fs_info->trans_mutex);
	cur_trans->commit_done = 1;
	wake_up(&cur_trans->commit_wait);
	put_transaction(cur_trans);
	put_transaction(cur_trans);
	mutex_unlock(&root->fs_info->trans_mutex);
	kmem_cache_free(btrfs_trans_handle_cachep, trans);

	drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
	return ret;
}
Commit	Line	Data
79154b1b CM	1	#include <linux/module.h>
	2	#include <linux/fs.h>
	3	#include "ctree.h"
	4	#include "disk-io.h"
	5	#include "transaction.h"
	6
78fae27e	7	static int total_trans = 0;
2c90e5d6 CM	8	extern struct kmem_cache *btrfs_trans_handle_cachep;
	9	extern struct kmem_cache *btrfs_transaction_cachep;
	10
0f7d52f4 CM	11	#define BTRFS_ROOT_TRANS_TAG 0
0f7d52f4 CM	12
2c90e5d6	13	#define TRANS_MAGIC 0xE1E10E
79154b1b CM	14	static void put_transaction(struct btrfs_transaction *transaction)
79154b1b CM	15	{
2c90e5d6	16	WARN_ON(transaction->use_count == 0);
79154b1b	17	transaction->use_count--;
2c90e5d6	18	WARN_ON(transaction->magic != TRANS_MAGIC);
78fae27e CM	19	if (transaction->use_count == 0) {
	20	WARN_ON(total_trans == 0);
	21	total_trans--;
8fd17795	22	list_del_init(&transaction->list);
2c90e5d6 CM	23	memset(transaction, 0, sizeof(*transaction));
2c90e5d6 CM	24	kmem_cache_free(btrfs_transaction_cachep, transaction);
78fae27e	25	}
79154b1b CM	26	}
	27
	28	static int join_transaction(struct btrfs_root *root)
	29	{
	30	struct btrfs_transaction *cur_trans;
	31	cur_trans = root->fs_info->running_transaction;
	32	if (!cur_trans) {
2c90e5d6 CM	33	cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
2c90e5d6 CM	34	GFP_NOFS);
78fae27e	35	total_trans++;
79154b1b	36	BUG_ON(!cur_trans);
0f7d52f4	37	root->fs_info->generation++;
79154b1b CM	38	root->fs_info->running_transaction = cur_trans;
79154b1b CM	39	cur_trans->num_writers = 0;
0f7d52f4	40	cur_trans->transid = root->fs_info->generation;
79154b1b CM	41	init_waitqueue_head(&cur_trans->writer_wait);
79154b1b CM	42	init_waitqueue_head(&cur_trans->commit_wait);
2c90e5d6	43	cur_trans->magic = TRANS_MAGIC;
79154b1b	44	cur_trans->in_commit = 0;
d5719762	45	cur_trans->use_count = 1;
79154b1b	46	cur_trans->commit_done = 0;
8fd17795	47	list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
7c4452b9	48	init_bit_radix(&cur_trans->dirty_pages);
79154b1b CM	49	}
	50	cur_trans->num_writers++;
	51	return 0;
	52	}
	53
	54	struct btrfs_trans_handle btrfs_start_transaction(struct btrfs_root root,
	55	int num_blocks)
	56	{
2c90e5d6 CM	57	struct btrfs_trans_handle *h =
2c90e5d6 CM	58	kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
79154b1b	59	int ret;
0f7d52f4	60	u64 running_trans_id;
79154b1b CM	61
	62	mutex_lock(&root->fs_info->trans_mutex);
	63	ret = join_transaction(root);
	64	BUG_ON(ret);
0f7d52f4 CM	65	running_trans_id = root->fs_info->running_transaction->transid;
	66
	67	if (root != root->fs_info->tree_root && root->last_trans <
	68	running_trans_id) {
	69	radix_tree_tag_set(&root->fs_info->fs_roots_radix,
2619ba1f CM	70	(unsigned long)root->root_key.objectid,
2619ba1f CM	71	BTRFS_ROOT_TRANS_TAG);
0f7d52f4 CM	72	root->commit_root = root->node;
	73	get_bh(root->node);
	74	}
	75	root->last_trans = running_trans_id;
	76	h->transid = running_trans_id;
79154b1b CM	77	h->transaction = root->fs_info->running_transaction;
	78	h->blocks_reserved = num_blocks;
	79	h->blocks_used = 0;
	80	root->fs_info->running_transaction->use_count++;
	81	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	82	h->magic = h->magic2 = TRANS_MAGIC;
79154b1b CM	83	return h;
	84	}
	85
	86	int btrfs_end_transaction(struct btrfs_trans_handle *trans,
	87	struct btrfs_root *root)
	88	{
	89	struct btrfs_transaction *cur_trans;
d6e4a428	90
2c90e5d6 CM	91	WARN_ON(trans->magic != TRANS_MAGIC);
2c90e5d6 CM	92	WARN_ON(trans->magic2 != TRANS_MAGIC);
79154b1b CM	93	mutex_lock(&root->fs_info->trans_mutex);
79154b1b CM	94	cur_trans = root->fs_info->running_transaction;
d5719762	95	WARN_ON(cur_trans->num_writers < 1);
79154b1b CM	96	if (waitqueue_active(&cur_trans->writer_wait))
	97	wake_up(&cur_trans->writer_wait);
	98	cur_trans->num_writers--;
	99	put_transaction(cur_trans);
	100	mutex_unlock(&root->fs_info->trans_mutex);
d6025579	101	memset(trans, 0, sizeof(*trans));
2c90e5d6	102	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b CM	103	return 0;
	104	}
	105
	106
	107	int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
	108	struct btrfs_root *root)
	109	{
7c4452b9 CM	110	unsigned long gang[16];
	111	int ret;
	112	int i;
	113	int err;
	114	int werr = 0;
	115	struct page *page;
	116	struct radix_tree_root *dirty_pages;
	117	struct inode *btree_inode = root->fs_info->btree_inode;
	118
	119	if (!trans \|\| !trans->transaction) {
	120	return filemap_write_and_wait(btree_inode->i_mapping);
	121	}
	122	dirty_pages = &trans->transaction->dirty_pages;
	123	while(1) {
	124	ret = find_first_radix_bit(dirty_pages, gang, ARRAY_SIZE(gang));
	125	if (!ret)
	126	break;
	127	for (i = 0; i < ret; i++) {
	128	/* FIXME EIO */
	129	clear_radix_bit(dirty_pages, gang[i]);
	130	page = find_lock_page(btree_inode->i_mapping,
	131	gang[i]);
	132	if (!page)
	133	continue;
	134	err = write_one_page(page, 0);
	135	if (err)
	136	werr = err;
	137	page_cache_release(page);
	138	}
	139	}
	140	err = filemap_fdatawait(btree_inode->i_mapping);
	141	if (err)
	142	werr = err;
	143	return werr;
79154b1b CM	144	}
	145
	146	int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
	147	struct btrfs_root *root)
	148	{
	149	int ret;
	150	u64 old_extent_block;
	151	struct btrfs_fs_info *fs_info = root->fs_info;
	152	struct btrfs_root *tree_root = fs_info->tree_root;
	153	struct btrfs_root *extent_root = fs_info->extent_root;
8352d8a4	154	struct btrfs_root *dev_root = fs_info->dev_root;
79154b1b	155
8352d8a4 CM	156	if (btrfs_super_device_root(fs_info->disk_super) !=
	157	bh_blocknr(dev_root->node)) {
	158	btrfs_set_super_device_root(fs_info->disk_super,
	159	bh_blocknr(dev_root->node));
	160	}
9078a3e1	161	btrfs_write_dirty_block_groups(trans, extent_root);
79154b1b CM	162	while(1) {
79154b1b CM	163	old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
7eccb903	164	if (old_extent_block == bh_blocknr(extent_root->node))
79154b1b CM	165	break;
79154b1b CM	166	btrfs_set_root_blocknr(&extent_root->root_item,
7eccb903	167	bh_blocknr(extent_root->node));
79154b1b CM	168	ret = btrfs_update_root(trans, tree_root,
	169	&extent_root->root_key,
	170	&extent_root->root_item);
	171	BUG_ON(ret);
9078a3e1	172	btrfs_write_dirty_block_groups(trans, extent_root);
79154b1b CM	173	}
	174	return 0;
	175	}
	176
	177	static int wait_for_commit(struct btrfs_root *root,
	178	struct btrfs_transaction *commit)
	179	{
	180	DEFINE_WAIT(wait);
79154b1b CM	181	while(!commit->commit_done) {
	182	prepare_to_wait(&commit->commit_wait, &wait,
	183	TASK_UNINTERRUPTIBLE);
	184	if (commit->commit_done)
	185	break;
	186	mutex_unlock(&root->fs_info->trans_mutex);
	187	schedule();
	188	mutex_lock(&root->fs_info->trans_mutex);
	189	}
	190	finish_wait(&commit->commit_wait, &wait);
	191	return 0;
	192	}
	193
0f7d52f4 CM	194	struct dirty_root {
	195	struct list_head list;
	196	struct btrfs_key snap_key;
	197	struct buffer_head *commit_root;
	198	struct btrfs_root *root;
	199	};
	200
	201	int add_dirty_roots(struct btrfs_trans_handle *trans,
	202	struct radix_tree_root radix, struct list_head list)
	203	{
	204	struct dirty_root *dirty;
	205	struct btrfs_root *gang[8];
	206	struct btrfs_root *root;
	207	int i;
	208	int ret;
	209	int err;
0f7d52f4 CM	210	while(1) {
	211	ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
	212	ARRAY_SIZE(gang),
	213	BTRFS_ROOT_TRANS_TAG);
	214	if (ret == 0)
	215	break;
	216	for (i = 0; i < ret; i++) {
	217	root = gang[i];
2619ba1f CM	218	radix_tree_tag_clear(radix,
	219	(unsigned long)root->root_key.objectid,
	220	BTRFS_ROOT_TRANS_TAG);
0f7d52f4	221	if (root->commit_root == root->node) {
7eccb903	222	WARN_ON(bh_blocknr(root->node) !=
0f7d52f4 CM	223	btrfs_root_blocknr(&root->root_item));
	224	brelse(root->commit_root);
	225	root->commit_root = NULL;
	226	continue;
	227	}
	228	dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
	229	BUG_ON(!dirty);
	230	memcpy(&dirty->snap_key, &root->root_key,
	231	sizeof(root->root_key));
	232	dirty->commit_root = root->commit_root;
	233	root->commit_root = NULL;
	234	dirty->root = root;
0f7d52f4 CM	235	root->root_key.offset = root->fs_info->generation;
0f7d52f4 CM	236	btrfs_set_root_blocknr(&root->root_item,
7eccb903	237	bh_blocknr(root->node));
0f7d52f4 CM	238	err = btrfs_insert_root(trans, root->fs_info->tree_root,
	239	&root->root_key,
	240	&root->root_item);
	241	BUG_ON(err);
	242	list_add(&dirty->list, list);
	243	}
	244	}
0f7d52f4 CM	245	return 0;
	246	}
	247
	248	int drop_dirty_roots(struct btrfs_root tree_root, struct list_head list)
	249	{
	250	struct dirty_root *dirty;
	251	struct btrfs_trans_handle *trans;
	252	int ret;
	253
	254	while(!list_empty(list)) {
	255	dirty = list_entry(list->next, struct dirty_root, list);
	256	list_del_init(&dirty->list);
	257	trans = btrfs_start_transaction(tree_root, 1);
0f7d52f4 CM	258	ret = btrfs_drop_snapshot(trans, dirty->root,
	259	dirty->commit_root);
	260	BUG_ON(ret);
	261
0f7d52f4 CM	262	ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
	263	BUG_ON(ret);
	264	ret = btrfs_end_transaction(trans, tree_root);
	265	BUG_ON(ret);
	266	kfree(dirty);
	267	}
	268	return 0;
	269	}
	270
79154b1b CM	271	int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
	272	struct btrfs_root *root)
	273	{
	274	int ret = 0;
79154b1b	275	struct btrfs_transaction *cur_trans;
8fd17795	276	struct btrfs_transaction *prev_trans = NULL;
0f7d52f4	277	struct list_head dirty_fs_roots;
79154b1b CM	278	DEFINE_WAIT(wait);
79154b1b CM	279
0f7d52f4	280	INIT_LIST_HEAD(&dirty_fs_roots);
d6e4a428	281
79154b1b CM	282	mutex_lock(&root->fs_info->trans_mutex);
	283	if (trans->transaction->in_commit) {
	284	cur_trans = trans->transaction;
	285	trans->transaction->use_count++;
	286	btrfs_end_transaction(trans, root);
	287	ret = wait_for_commit(root, cur_trans);
	288	BUG_ON(ret);
	289	put_transaction(cur_trans);
	290	mutex_unlock(&root->fs_info->trans_mutex);
	291	return 0;
	292	}
2c90e5d6 CM	293	cur_trans = trans->transaction;
2c90e5d6 CM	294	trans->transaction->in_commit = 1;
79154b1b	295	while (trans->transaction->num_writers > 1) {
2c90e5d6	296	WARN_ON(cur_trans != trans->transaction);
79154b1b CM	297	prepare_to_wait(&trans->transaction->writer_wait, &wait,
	298	TASK_UNINTERRUPTIBLE);
	299	if (trans->transaction->num_writers <= 1)
	300	break;
	301	mutex_unlock(&root->fs_info->trans_mutex);
	302	schedule();
	303	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6	304	finish_wait(&trans->transaction->writer_wait, &wait);
79154b1b CM	305	}
79154b1b CM	306	finish_wait(&trans->transaction->writer_wait, &wait);
2c90e5d6	307	WARN_ON(cur_trans != trans->transaction);
0f7d52f4	308	add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
79154b1b CM	309	ret = btrfs_commit_tree_roots(trans, root);
79154b1b CM	310	BUG_ON(ret);
78fae27e CM	311	cur_trans = root->fs_info->running_transaction;
78fae27e CM	312	root->fs_info->running_transaction = NULL;
8fd17795 CM	313	if (cur_trans->list.prev != &root->fs_info->trans_list) {
	314	prev_trans = list_entry(cur_trans->list.prev,
	315	struct btrfs_transaction, list);
	316	if (prev_trans->commit_done)
	317	prev_trans = NULL;
	318	else
	319	prev_trans->use_count++;
	320	}
78fae27e	321	mutex_unlock(&root->fs_info->trans_mutex);
8fd17795	322	mutex_unlock(&root->fs_info->fs_mutex);
79154b1b	323	ret = btrfs_write_and_wait_transaction(trans, root);
8fd17795 CM	324	if (prev_trans) {
	325	mutex_lock(&root->fs_info->trans_mutex);
	326	wait_for_commit(root, prev_trans);
	327	put_transaction(prev_trans);
	328	mutex_unlock(&root->fs_info->trans_mutex);
	329	}
	330	btrfs_set_super_generation(root->fs_info->disk_super,
	331	cur_trans->transid);
79154b1b	332	BUG_ON(ret);
79154b1b	333	write_ctree_super(trans, root);
8fd17795 CM	334
8fd17795 CM	335	mutex_lock(&root->fs_info->fs_mutex);
78fae27e CM	336	btrfs_finish_extent_commit(trans, root);
78fae27e CM	337	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6 CM	338	cur_trans->commit_done = 1;
2c90e5d6 CM	339	wake_up(&cur_trans->commit_wait);
78fae27e	340	put_transaction(cur_trans);
79154b1b	341	put_transaction(cur_trans);
78fae27e	342	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	343	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b	344
0f7d52f4	345	drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
79154b1b CM	346	return ret;
	347	}
	348