[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 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--;
		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->running_transaction = cur_trans;
		cur_trans->num_writers = 0;
		cur_trans->transid = root->root_key.offset + 1;
		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;
	}
	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;

	mutex_lock(&root->fs_info->trans_mutex);
	ret = join_transaction(root);
	BUG_ON(ret);
	h->transid = root->fs_info->running_transaction->transid;
	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)
{
	filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
	return 0;
}

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 *inode_root = fs_info->inode_root;

	btrfs_set_root_blocknr(&inode_root->root_item,
			       inode_root->node->b_blocknr);
	ret = btrfs_update_root(trans, tree_root,
				&inode_root->root_key,
				&inode_root->root_item);
	BUG_ON(ret);
	while(1) {
		old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
		if (old_extent_block == extent_root->node->b_blocknr)
			break;
		btrfs_set_root_blocknr(&extent_root->root_item,
				       extent_root->node->b_blocknr);
		ret = btrfs_update_root(trans, tree_root,
					&extent_root->root_key,
					&extent_root->root_item);
		BUG_ON(ret);
	}
	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;
}

int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root)
{
	int ret = 0;
	struct buffer_head *snap;
	struct btrfs_key snap_key;
	struct btrfs_transaction *cur_trans;
	DEFINE_WAIT(wait);

	mutex_lock(&root->fs_info->trans_mutex);
	if (trans->transaction->in_commit) {
printk("already in commit!, waiting\n");
		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);
	if (root->node != root->commit_root) {
		memcpy(&snap_key, &root->root_key, sizeof(snap_key));
		root->root_key.offset++;
	}

	if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) {
		btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr);
		ret = btrfs_insert_root(trans, root->fs_info->tree_root,
					&root->root_key, &root->root_item);
		BUG_ON(ret);
	}

	ret = btrfs_commit_tree_roots(trans, root);
	BUG_ON(ret);
	cur_trans = root->fs_info->running_transaction;
	root->fs_info->running_transaction = NULL;
	mutex_unlock(&root->fs_info->trans_mutex);
	ret = btrfs_write_and_wait_transaction(trans, root);
	BUG_ON(ret);

	write_ctree_super(trans, root);
	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);
	if (root->node != root->commit_root) {
		trans = btrfs_start_transaction(root, 1);
		snap = root->commit_root;
		root->commit_root = root->node;
		get_bh(root->node);
		ret = btrfs_drop_snapshot(trans, root, snap);
		BUG_ON(ret);

		ret = btrfs_del_root(trans, root->fs_info->tree_root,
				     &snap_key);
		BUG_ON(ret);
		root->fs_info->generation = root->root_key.offset + 1;
		ret = btrfs_end_transaction(trans, root);
		BUG_ON(ret);
	}
	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
	11	#define TRANS_MAGIC 0xE1E10E
79154b1b CM	12	static void put_transaction(struct btrfs_transaction *transaction)
79154b1b CM	13	{
2c90e5d6	14	WARN_ON(transaction->use_count == 0);
79154b1b	15	transaction->use_count--;
2c90e5d6	16	WARN_ON(transaction->magic != TRANS_MAGIC);
78fae27e CM	17	if (transaction->use_count == 0) {
	18	WARN_ON(total_trans == 0);
	19	total_trans--;
2c90e5d6 CM	20	memset(transaction, 0, sizeof(*transaction));
2c90e5d6 CM	21	kmem_cache_free(btrfs_transaction_cachep, transaction);
78fae27e	22	}
79154b1b CM	23	}
	24
	25	static int join_transaction(struct btrfs_root *root)
	26	{
	27	struct btrfs_transaction *cur_trans;
	28	cur_trans = root->fs_info->running_transaction;
	29	if (!cur_trans) {
2c90e5d6 CM	30	cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
2c90e5d6 CM	31	GFP_NOFS);
78fae27e	32	total_trans++;
79154b1b CM	33	BUG_ON(!cur_trans);
	34	root->fs_info->running_transaction = cur_trans;
	35	cur_trans->num_writers = 0;
	36	cur_trans->transid = root->root_key.offset + 1;
	37	init_waitqueue_head(&cur_trans->writer_wait);
	38	init_waitqueue_head(&cur_trans->commit_wait);
2c90e5d6	39	cur_trans->magic = TRANS_MAGIC;
79154b1b	40	cur_trans->in_commit = 0;
d5719762	41	cur_trans->use_count = 1;
79154b1b CM	42	cur_trans->commit_done = 0;
	43	}
	44	cur_trans->num_writers++;
	45	return 0;
	46	}
	47
	48	struct btrfs_trans_handle btrfs_start_transaction(struct btrfs_root root,
	49	int num_blocks)
	50	{
2c90e5d6 CM	51	struct btrfs_trans_handle *h =
2c90e5d6 CM	52	kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
79154b1b CM	53	int ret;
	54
	55	mutex_lock(&root->fs_info->trans_mutex);
	56	ret = join_transaction(root);
	57	BUG_ON(ret);
	58	h->transid = root->fs_info->running_transaction->transid;
	59	h->transaction = root->fs_info->running_transaction;
	60	h->blocks_reserved = num_blocks;
	61	h->blocks_used = 0;
	62	root->fs_info->running_transaction->use_count++;
	63	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	64	h->magic = h->magic2 = TRANS_MAGIC;
79154b1b CM	65	return h;
	66	}
	67
	68	int btrfs_end_transaction(struct btrfs_trans_handle *trans,
	69	struct btrfs_root *root)
	70	{
	71	struct btrfs_transaction *cur_trans;
2c90e5d6 CM	72	WARN_ON(trans->magic != TRANS_MAGIC);
2c90e5d6 CM	73	WARN_ON(trans->magic2 != TRANS_MAGIC);
79154b1b CM	74	mutex_lock(&root->fs_info->trans_mutex);
79154b1b CM	75	cur_trans = root->fs_info->running_transaction;
d5719762	76	WARN_ON(cur_trans->num_writers < 1);
79154b1b CM	77	if (waitqueue_active(&cur_trans->writer_wait))
	78	wake_up(&cur_trans->writer_wait);
	79	cur_trans->num_writers--;
	80	put_transaction(cur_trans);
	81	mutex_unlock(&root->fs_info->trans_mutex);
d6025579	82	memset(trans, 0, sizeof(*trans));
2c90e5d6	83	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b CM	84	return 0;
	85	}
	86
	87
	88	int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
	89	struct btrfs_root *root)
	90	{
7cfcc17e	91	filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
79154b1b CM	92	return 0;
	93	}
	94
	95	int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
	96	struct btrfs_root *root)
	97	{
	98	int ret;
	99	u64 old_extent_block;
	100	struct btrfs_fs_info *fs_info = root->fs_info;
	101	struct btrfs_root *tree_root = fs_info->tree_root;
	102	struct btrfs_root *extent_root = fs_info->extent_root;
	103	struct btrfs_root *inode_root = fs_info->inode_root;
	104
	105	btrfs_set_root_blocknr(&inode_root->root_item,
	106	inode_root->node->b_blocknr);
	107	ret = btrfs_update_root(trans, tree_root,
	108	&inode_root->root_key,
	109	&inode_root->root_item);
	110	BUG_ON(ret);
	111	while(1) {
	112	old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
	113	if (old_extent_block == extent_root->node->b_blocknr)
	114	break;
	115	btrfs_set_root_blocknr(&extent_root->root_item,
	116	extent_root->node->b_blocknr);
	117	ret = btrfs_update_root(trans, tree_root,
	118	&extent_root->root_key,
	119	&extent_root->root_item);
	120	BUG_ON(ret);
	121	}
	122	return 0;
	123	}
	124
	125	static int wait_for_commit(struct btrfs_root *root,
	126	struct btrfs_transaction *commit)
	127	{
	128	DEFINE_WAIT(wait);
79154b1b CM	129	while(!commit->commit_done) {
	130	prepare_to_wait(&commit->commit_wait, &wait,
	131	TASK_UNINTERRUPTIBLE);
	132	if (commit->commit_done)
	133	break;
	134	mutex_unlock(&root->fs_info->trans_mutex);
	135	schedule();
	136	mutex_lock(&root->fs_info->trans_mutex);
	137	}
	138	finish_wait(&commit->commit_wait, &wait);
	139	return 0;
	140	}
	141
	142	int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
	143	struct btrfs_root *root)
	144	{
	145	int ret = 0;
78fae27e	146	struct buffer_head *snap;
79154b1b CM	147	struct btrfs_key snap_key;
	148	struct btrfs_transaction *cur_trans;
	149	DEFINE_WAIT(wait);
	150
	151	mutex_lock(&root->fs_info->trans_mutex);
	152	if (trans->transaction->in_commit) {
2c90e5d6	153	printk("already in commit!, waiting\n");
79154b1b CM	154	cur_trans = trans->transaction;
	155	trans->transaction->use_count++;
	156	btrfs_end_transaction(trans, root);
	157	ret = wait_for_commit(root, cur_trans);
	158	BUG_ON(ret);
	159	put_transaction(cur_trans);
	160	mutex_unlock(&root->fs_info->trans_mutex);
	161	return 0;
	162	}
2c90e5d6 CM	163	cur_trans = trans->transaction;
2c90e5d6 CM	164	trans->transaction->in_commit = 1;
79154b1b	165	while (trans->transaction->num_writers > 1) {
2c90e5d6	166	WARN_ON(cur_trans != trans->transaction);
79154b1b CM	167	prepare_to_wait(&trans->transaction->writer_wait, &wait,
	168	TASK_UNINTERRUPTIBLE);
	169	if (trans->transaction->num_writers <= 1)
	170	break;
	171	mutex_unlock(&root->fs_info->trans_mutex);
	172	schedule();
	173	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6	174	finish_wait(&trans->transaction->writer_wait, &wait);
79154b1b CM	175	}
79154b1b CM	176	finish_wait(&trans->transaction->writer_wait, &wait);
2c90e5d6	177	WARN_ON(cur_trans != trans->transaction);
d5719762 CM	178	if (root->node != root->commit_root) {
	179	memcpy(&snap_key, &root->root_key, sizeof(snap_key));
	180	root->root_key.offset++;
	181	}
	182
79154b1b CM	183	if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) {
	184	btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr);
	185	ret = btrfs_insert_root(trans, root->fs_info->tree_root,
	186	&root->root_key, &root->root_item);
	187	BUG_ON(ret);
	188	}
	189
	190	ret = btrfs_commit_tree_roots(trans, root);
	191	BUG_ON(ret);
78fae27e CM	192	cur_trans = root->fs_info->running_transaction;
	193	root->fs_info->running_transaction = NULL;
	194	mutex_unlock(&root->fs_info->trans_mutex);
79154b1b CM	195	ret = btrfs_write_and_wait_transaction(trans, root);
	196	BUG_ON(ret);
	197
	198	write_ctree_super(trans, root);
78fae27e CM	199	btrfs_finish_extent_commit(trans, root);
78fae27e CM	200	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6 CM	201	cur_trans->commit_done = 1;
2c90e5d6 CM	202	wake_up(&cur_trans->commit_wait);
78fae27e	203	put_transaction(cur_trans);
79154b1b	204	put_transaction(cur_trans);
78fae27e	205	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	206	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b CM	207	if (root->node != root->commit_root) {
79154b1b CM	208	trans = btrfs_start_transaction(root, 1);
78fae27e	209	snap = root->commit_root;
79154b1b CM	210	root->commit_root = root->node;
	211	get_bh(root->node);
	212	ret = btrfs_drop_snapshot(trans, root, snap);
	213	BUG_ON(ret);
	214
	215	ret = btrfs_del_root(trans, root->fs_info->tree_root,
	216	&snap_key);
22b0ebda CM	217	BUG_ON(ret);
	218	root->fs_info->generation = root->root_key.offset + 1;
	219	ret = btrfs_end_transaction(trans, root);
	220	BUG_ON(ret);
79154b1b	221	}
79154b1b CM	222	return ret;
	223	}
	224