[deliverable/linux.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;
	h->block_group = NULL;
	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;
};

static 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;
}

static 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;
31f3c99b	80	h->block_group = NULL;
79154b1b CM	81	root->fs_info->running_transaction->use_count++;
79154b1b CM	82	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	83	h->magic = h->magic2 = TRANS_MAGIC;
79154b1b CM	84	return h;
	85	}
	86
	87	int btrfs_end_transaction(struct btrfs_trans_handle *trans,
	88	struct btrfs_root *root)
	89	{
	90	struct btrfs_transaction *cur_trans;
d6e4a428	91
2c90e5d6 CM	92	WARN_ON(trans->magic != TRANS_MAGIC);
2c90e5d6 CM	93	WARN_ON(trans->magic2 != TRANS_MAGIC);
79154b1b CM	94	mutex_lock(&root->fs_info->trans_mutex);
79154b1b CM	95	cur_trans = root->fs_info->running_transaction;
d5719762	96	WARN_ON(cur_trans->num_writers < 1);
79154b1b CM	97	if (waitqueue_active(&cur_trans->writer_wait))
	98	wake_up(&cur_trans->writer_wait);
	99	cur_trans->num_writers--;
	100	put_transaction(cur_trans);
	101	mutex_unlock(&root->fs_info->trans_mutex);
d6025579	102	memset(trans, 0, sizeof(*trans));
2c90e5d6	103	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b CM	104	return 0;
	105	}
	106
	107
	108	int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
	109	struct btrfs_root *root)
	110	{
7c4452b9 CM	111	unsigned long gang[16];
	112	int ret;
	113	int i;
	114	int err;
	115	int werr = 0;
	116	struct page *page;
	117	struct radix_tree_root *dirty_pages;
	118	struct inode *btree_inode = root->fs_info->btree_inode;
	119
	120	if (!trans \|\| !trans->transaction) {
	121	return filemap_write_and_wait(btree_inode->i_mapping);
	122	}
	123	dirty_pages = &trans->transaction->dirty_pages;
	124	while(1) {
	125	ret = find_first_radix_bit(dirty_pages, gang, ARRAY_SIZE(gang));
	126	if (!ret)
	127	break;
	128	for (i = 0; i < ret; i++) {
	129	/* FIXME EIO */
	130	clear_radix_bit(dirty_pages, gang[i]);
	131	page = find_lock_page(btree_inode->i_mapping,
	132	gang[i]);
	133	if (!page)
	134	continue;
	135	err = write_one_page(page, 0);
	136	if (err)
	137	werr = err;
	138	page_cache_release(page);
	139	}
	140	}
	141	err = filemap_fdatawait(btree_inode->i_mapping);
	142	if (err)
	143	werr = err;
	144	return werr;
79154b1b CM	145	}
	146
	147	int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
	148	struct btrfs_root *root)
	149	{
	150	int ret;
	151	u64 old_extent_block;
	152	struct btrfs_fs_info *fs_info = root->fs_info;
	153	struct btrfs_root *tree_root = fs_info->tree_root;
	154	struct btrfs_root *extent_root = fs_info->extent_root;
8352d8a4	155	struct btrfs_root *dev_root = fs_info->dev_root;
79154b1b	156
8352d8a4 CM	157	if (btrfs_super_device_root(fs_info->disk_super) !=
	158	bh_blocknr(dev_root->node)) {
	159	btrfs_set_super_device_root(fs_info->disk_super,
	160	bh_blocknr(dev_root->node));
	161	}
9078a3e1	162	btrfs_write_dirty_block_groups(trans, extent_root);
79154b1b CM	163	while(1) {
79154b1b CM	164	old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
7eccb903	165	if (old_extent_block == bh_blocknr(extent_root->node))
79154b1b CM	166	break;
79154b1b CM	167	btrfs_set_root_blocknr(&extent_root->root_item,
7eccb903	168	bh_blocknr(extent_root->node));
79154b1b CM	169	ret = btrfs_update_root(trans, tree_root,
	170	&extent_root->root_key,
	171	&extent_root->root_item);
	172	BUG_ON(ret);
9078a3e1	173	btrfs_write_dirty_block_groups(trans, extent_root);
79154b1b CM	174	}
	175	return 0;
	176	}
	177
	178	static int wait_for_commit(struct btrfs_root *root,
	179	struct btrfs_transaction *commit)
	180	{
	181	DEFINE_WAIT(wait);
79154b1b CM	182	while(!commit->commit_done) {
	183	prepare_to_wait(&commit->commit_wait, &wait,
	184	TASK_UNINTERRUPTIBLE);
	185	if (commit->commit_done)
	186	break;
	187	mutex_unlock(&root->fs_info->trans_mutex);
	188	schedule();
	189	mutex_lock(&root->fs_info->trans_mutex);
	190	}
	191	finish_wait(&commit->commit_wait, &wait);
	192	return 0;
	193	}
	194
0f7d52f4 CM	195	struct dirty_root {
	196	struct list_head list;
	197	struct btrfs_key snap_key;
	198	struct buffer_head *commit_root;
	199	struct btrfs_root *root;
	200	};
	201
35b7e476 CM	202	static int add_dirty_roots(struct btrfs_trans_handle *trans,
	203	struct radix_tree_root *radix,
	204	struct list_head *list)
0f7d52f4 CM	205	{
	206	struct dirty_root *dirty;
	207	struct btrfs_root *gang[8];
	208	struct btrfs_root *root;
	209	int i;
	210	int ret;
	211	int err;
0f7d52f4 CM	212	while(1) {
	213	ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
	214	ARRAY_SIZE(gang),
	215	BTRFS_ROOT_TRANS_TAG);
	216	if (ret == 0)
	217	break;
	218	for (i = 0; i < ret; i++) {
	219	root = gang[i];
2619ba1f CM	220	radix_tree_tag_clear(radix,
	221	(unsigned long)root->root_key.objectid,
	222	BTRFS_ROOT_TRANS_TAG);
0f7d52f4	223	if (root->commit_root == root->node) {
7eccb903	224	WARN_ON(bh_blocknr(root->node) !=
0f7d52f4 CM	225	btrfs_root_blocknr(&root->root_item));
	226	brelse(root->commit_root);
	227	root->commit_root = NULL;
	228	continue;
	229	}
	230	dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
	231	BUG_ON(!dirty);
	232	memcpy(&dirty->snap_key, &root->root_key,
	233	sizeof(root->root_key));
	234	dirty->commit_root = root->commit_root;
	235	root->commit_root = NULL;
	236	dirty->root = root;
0f7d52f4 CM	237	root->root_key.offset = root->fs_info->generation;
0f7d52f4 CM	238	btrfs_set_root_blocknr(&root->root_item,
7eccb903	239	bh_blocknr(root->node));
0f7d52f4 CM	240	err = btrfs_insert_root(trans, root->fs_info->tree_root,
	241	&root->root_key,
	242	&root->root_item);
	243	BUG_ON(err);
	244	list_add(&dirty->list, list);
	245	}
	246	}
0f7d52f4 CM	247	return 0;
	248	}
	249
35b7e476 CM	250	static int drop_dirty_roots(struct btrfs_root *tree_root,
35b7e476 CM	251	struct list_head *list)
0f7d52f4 CM	252	{
	253	struct dirty_root *dirty;
	254	struct btrfs_trans_handle *trans;
	255	int ret;
	256
	257	while(!list_empty(list)) {
	258	dirty = list_entry(list->next, struct dirty_root, list);
	259	list_del_init(&dirty->list);
	260	trans = btrfs_start_transaction(tree_root, 1);
0f7d52f4 CM	261	ret = btrfs_drop_snapshot(trans, dirty->root,
	262	dirty->commit_root);
	263	BUG_ON(ret);
	264
0f7d52f4 CM	265	ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
	266	BUG_ON(ret);
	267	ret = btrfs_end_transaction(trans, tree_root);
	268	BUG_ON(ret);
	269	kfree(dirty);
	270	}
	271	return 0;
	272	}
	273
79154b1b CM	274	int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
	275	struct btrfs_root *root)
	276	{
	277	int ret = 0;
79154b1b	278	struct btrfs_transaction *cur_trans;
8fd17795	279	struct btrfs_transaction *prev_trans = NULL;
0f7d52f4	280	struct list_head dirty_fs_roots;
79154b1b CM	281	DEFINE_WAIT(wait);
79154b1b CM	282
0f7d52f4	283	INIT_LIST_HEAD(&dirty_fs_roots);
d6e4a428	284
79154b1b CM	285	mutex_lock(&root->fs_info->trans_mutex);
	286	if (trans->transaction->in_commit) {
	287	cur_trans = trans->transaction;
	288	trans->transaction->use_count++;
	289	btrfs_end_transaction(trans, root);
	290	ret = wait_for_commit(root, cur_trans);
	291	BUG_ON(ret);
	292	put_transaction(cur_trans);
	293	mutex_unlock(&root->fs_info->trans_mutex);
	294	return 0;
	295	}
2c90e5d6 CM	296	cur_trans = trans->transaction;
2c90e5d6 CM	297	trans->transaction->in_commit = 1;
79154b1b	298	while (trans->transaction->num_writers > 1) {
2c90e5d6	299	WARN_ON(cur_trans != trans->transaction);
79154b1b CM	300	prepare_to_wait(&trans->transaction->writer_wait, &wait,
	301	TASK_UNINTERRUPTIBLE);
	302	if (trans->transaction->num_writers <= 1)
	303	break;
	304	mutex_unlock(&root->fs_info->trans_mutex);
	305	schedule();
	306	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6	307	finish_wait(&trans->transaction->writer_wait, &wait);
79154b1b CM	308	}
79154b1b CM	309	finish_wait(&trans->transaction->writer_wait, &wait);
2c90e5d6	310	WARN_ON(cur_trans != trans->transaction);
0f7d52f4	311	add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
79154b1b CM	312	ret = btrfs_commit_tree_roots(trans, root);
79154b1b CM	313	BUG_ON(ret);
78fae27e CM	314	cur_trans = root->fs_info->running_transaction;
78fae27e CM	315	root->fs_info->running_transaction = NULL;
8fd17795 CM	316	if (cur_trans->list.prev != &root->fs_info->trans_list) {
	317	prev_trans = list_entry(cur_trans->list.prev,
	318	struct btrfs_transaction, list);
	319	if (prev_trans->commit_done)
	320	prev_trans = NULL;
	321	else
	322	prev_trans->use_count++;
	323	}
78fae27e	324	mutex_unlock(&root->fs_info->trans_mutex);
8fd17795	325	mutex_unlock(&root->fs_info->fs_mutex);
79154b1b	326	ret = btrfs_write_and_wait_transaction(trans, root);
8fd17795 CM	327	if (prev_trans) {
	328	mutex_lock(&root->fs_info->trans_mutex);
	329	wait_for_commit(root, prev_trans);
	330	put_transaction(prev_trans);
	331	mutex_unlock(&root->fs_info->trans_mutex);
	332	}
	333	btrfs_set_super_generation(root->fs_info->disk_super,
	334	cur_trans->transid);
79154b1b	335	BUG_ON(ret);
79154b1b	336	write_ctree_super(trans, root);
8fd17795 CM	337
8fd17795 CM	338	mutex_lock(&root->fs_info->fs_mutex);
78fae27e CM	339	btrfs_finish_extent_commit(trans, root);
78fae27e CM	340	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6 CM	341	cur_trans->commit_done = 1;
2c90e5d6 CM	342	wake_up(&cur_trans->commit_wait);
78fae27e	343	put_transaction(cur_trans);
79154b1b	344	put_transaction(cur_trans);
78fae27e	345	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	346	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b	347
0f7d52f4	348	drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
79154b1b CM	349	return ret;
	350	}
	351