[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--;
		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;
	}
	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, 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)
{
	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;

	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;
}

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,
					     BTRFS_ROOT_TRANS_TAG);
			if (root->commit_root == root->node) {
				WARN_ON(root->node->b_blocknr !=
					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,
					       root->node->b_blocknr);
			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 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;
	btrfs_set_super_generation(root->fs_info->disk_super,
				   root->fs_info->generation + 1);
	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);

	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--;
2c90e5d6 CM	22	memset(transaction, 0, sizeof(*transaction));
2c90e5d6 CM	23	kmem_cache_free(btrfs_transaction_cachep, transaction);
78fae27e	24	}
79154b1b CM	25	}
	26
	27	static int join_transaction(struct btrfs_root *root)
	28	{
	29	struct btrfs_transaction *cur_trans;
	30	cur_trans = root->fs_info->running_transaction;
	31	if (!cur_trans) {
2c90e5d6 CM	32	cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
2c90e5d6 CM	33	GFP_NOFS);
78fae27e	34	total_trans++;
79154b1b	35	BUG_ON(!cur_trans);
0f7d52f4	36	root->fs_info->generation++;
79154b1b CM	37	root->fs_info->running_transaction = cur_trans;
79154b1b CM	38	cur_trans->num_writers = 0;
0f7d52f4	39	cur_trans->transid = root->fs_info->generation;
79154b1b CM	40	init_waitqueue_head(&cur_trans->writer_wait);
79154b1b CM	41	init_waitqueue_head(&cur_trans->commit_wait);
2c90e5d6	42	cur_trans->magic = TRANS_MAGIC;
79154b1b	43	cur_trans->in_commit = 0;
d5719762	44	cur_trans->use_count = 1;
79154b1b CM	45	cur_trans->commit_done = 0;
	46	}
	47	cur_trans->num_writers++;
	48	return 0;
	49	}
	50
	51	struct btrfs_trans_handle btrfs_start_transaction(struct btrfs_root root,
	52	int num_blocks)
	53	{
2c90e5d6 CM	54	struct btrfs_trans_handle *h =
2c90e5d6 CM	55	kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
79154b1b	56	int ret;
0f7d52f4	57	u64 running_trans_id;
79154b1b CM	58
	59	mutex_lock(&root->fs_info->trans_mutex);
	60	ret = join_transaction(root);
	61	BUG_ON(ret);
0f7d52f4 CM	62	running_trans_id = root->fs_info->running_transaction->transid;
	63
	64	if (root != root->fs_info->tree_root && root->last_trans <
	65	running_trans_id) {
	66	radix_tree_tag_set(&root->fs_info->fs_roots_radix,
	67	(unsigned long)root, BTRFS_ROOT_TRANS_TAG);
	68	root->commit_root = root->node;
	69	get_bh(root->node);
	70	}
	71	root->last_trans = running_trans_id;
	72	h->transid = running_trans_id;
79154b1b CM	73	h->transaction = root->fs_info->running_transaction;
	74	h->blocks_reserved = num_blocks;
	75	h->blocks_used = 0;
	76	root->fs_info->running_transaction->use_count++;
	77	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	78	h->magic = h->magic2 = TRANS_MAGIC;
79154b1b CM	79	return h;
	80	}
	81
	82	int btrfs_end_transaction(struct btrfs_trans_handle *trans,
	83	struct btrfs_root *root)
	84	{
	85	struct btrfs_transaction *cur_trans;
d6e4a428	86
2c90e5d6 CM	87	WARN_ON(trans->magic != TRANS_MAGIC);
2c90e5d6 CM	88	WARN_ON(trans->magic2 != TRANS_MAGIC);
79154b1b CM	89	mutex_lock(&root->fs_info->trans_mutex);
79154b1b CM	90	cur_trans = root->fs_info->running_transaction;
d5719762	91	WARN_ON(cur_trans->num_writers < 1);
79154b1b CM	92	if (waitqueue_active(&cur_trans->writer_wait))
	93	wake_up(&cur_trans->writer_wait);
	94	cur_trans->num_writers--;
	95	put_transaction(cur_trans);
	96	mutex_unlock(&root->fs_info->trans_mutex);
d6025579	97	memset(trans, 0, sizeof(*trans));
2c90e5d6	98	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b CM	99	return 0;
	100	}
	101
	102
	103	int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
	104	struct btrfs_root *root)
	105	{
7cfcc17e	106	filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
79154b1b CM	107	return 0;
	108	}
	109
	110	int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
	111	struct btrfs_root *root)
	112	{
	113	int ret;
	114	u64 old_extent_block;
	115	struct btrfs_fs_info *fs_info = root->fs_info;
	116	struct btrfs_root *tree_root = fs_info->tree_root;
	117	struct btrfs_root *extent_root = fs_info->extent_root;
79154b1b	118
79154b1b CM	119	while(1) {
	120	old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
	121	if (old_extent_block == extent_root->node->b_blocknr)
	122	break;
	123	btrfs_set_root_blocknr(&extent_root->root_item,
	124	extent_root->node->b_blocknr);
	125	ret = btrfs_update_root(trans, tree_root,
	126	&extent_root->root_key,
	127	&extent_root->root_item);
	128	BUG_ON(ret);
	129	}
	130	return 0;
	131	}
	132
	133	static int wait_for_commit(struct btrfs_root *root,
	134	struct btrfs_transaction *commit)
	135	{
	136	DEFINE_WAIT(wait);
79154b1b CM	137	while(!commit->commit_done) {
	138	prepare_to_wait(&commit->commit_wait, &wait,
	139	TASK_UNINTERRUPTIBLE);
	140	if (commit->commit_done)
	141	break;
	142	mutex_unlock(&root->fs_info->trans_mutex);
	143	schedule();
	144	mutex_lock(&root->fs_info->trans_mutex);
	145	}
	146	finish_wait(&commit->commit_wait, &wait);
	147	return 0;
	148	}
	149
0f7d52f4 CM	150	struct dirty_root {
	151	struct list_head list;
	152	struct btrfs_key snap_key;
	153	struct buffer_head *commit_root;
	154	struct btrfs_root *root;
	155	};
	156
	157	int add_dirty_roots(struct btrfs_trans_handle *trans,
	158	struct radix_tree_root radix, struct list_head list)
	159	{
	160	struct dirty_root *dirty;
	161	struct btrfs_root *gang[8];
	162	struct btrfs_root *root;
	163	int i;
	164	int ret;
	165	int err;
0f7d52f4 CM	166	while(1) {
	167	ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
	168	ARRAY_SIZE(gang),
	169	BTRFS_ROOT_TRANS_TAG);
	170	if (ret == 0)
	171	break;
	172	for (i = 0; i < ret; i++) {
	173	root = gang[i];
	174	radix_tree_tag_clear(radix, (unsigned long)root,
	175	BTRFS_ROOT_TRANS_TAG);
	176	if (root->commit_root == root->node) {
	177	WARN_ON(root->node->b_blocknr !=
	178	btrfs_root_blocknr(&root->root_item));
	179	brelse(root->commit_root);
	180	root->commit_root = NULL;
	181	continue;
	182	}
	183	dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
	184	BUG_ON(!dirty);
	185	memcpy(&dirty->snap_key, &root->root_key,
	186	sizeof(root->root_key));
	187	dirty->commit_root = root->commit_root;
	188	root->commit_root = NULL;
	189	dirty->root = root;
0f7d52f4 CM	190	root->root_key.offset = root->fs_info->generation;
	191	btrfs_set_root_blocknr(&root->root_item,
	192	root->node->b_blocknr);
	193	err = btrfs_insert_root(trans, root->fs_info->tree_root,
	194	&root->root_key,
	195	&root->root_item);
	196	BUG_ON(err);
	197	list_add(&dirty->list, list);
	198	}
	199	}
0f7d52f4 CM	200	return 0;
	201	}
	202
	203	int drop_dirty_roots(struct btrfs_root tree_root, struct list_head list)
	204	{
	205	struct dirty_root *dirty;
	206	struct btrfs_trans_handle *trans;
	207	int ret;
	208
	209	while(!list_empty(list)) {
	210	dirty = list_entry(list->next, struct dirty_root, list);
	211	list_del_init(&dirty->list);
	212	trans = btrfs_start_transaction(tree_root, 1);
0f7d52f4 CM	213	ret = btrfs_drop_snapshot(trans, dirty->root,
	214	dirty->commit_root);
	215	BUG_ON(ret);
	216
0f7d52f4 CM	217	ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
	218	BUG_ON(ret);
	219	ret = btrfs_end_transaction(trans, tree_root);
	220	BUG_ON(ret);
	221	kfree(dirty);
	222	}
	223	return 0;
	224	}
	225
79154b1b CM	226	int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
	227	struct btrfs_root *root)
	228	{
	229	int ret = 0;
79154b1b	230	struct btrfs_transaction *cur_trans;
0f7d52f4	231	struct list_head dirty_fs_roots;
79154b1b CM	232	DEFINE_WAIT(wait);
79154b1b CM	233
0f7d52f4	234	INIT_LIST_HEAD(&dirty_fs_roots);
d6e4a428	235
79154b1b CM	236	mutex_lock(&root->fs_info->trans_mutex);
	237	if (trans->transaction->in_commit) {
	238	cur_trans = trans->transaction;
	239	trans->transaction->use_count++;
	240	btrfs_end_transaction(trans, root);
	241	ret = wait_for_commit(root, cur_trans);
	242	BUG_ON(ret);
	243	put_transaction(cur_trans);
	244	mutex_unlock(&root->fs_info->trans_mutex);
	245	return 0;
	246	}
2c90e5d6 CM	247	cur_trans = trans->transaction;
2c90e5d6 CM	248	trans->transaction->in_commit = 1;
79154b1b	249	while (trans->transaction->num_writers > 1) {
2c90e5d6	250	WARN_ON(cur_trans != trans->transaction);
79154b1b CM	251	prepare_to_wait(&trans->transaction->writer_wait, &wait,
	252	TASK_UNINTERRUPTIBLE);
	253	if (trans->transaction->num_writers <= 1)
	254	break;
	255	mutex_unlock(&root->fs_info->trans_mutex);
	256	schedule();
	257	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6	258	finish_wait(&trans->transaction->writer_wait, &wait);
79154b1b CM	259	}
79154b1b CM	260	finish_wait(&trans->transaction->writer_wait, &wait);
2c90e5d6	261	WARN_ON(cur_trans != trans->transaction);
0f7d52f4	262	add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
79154b1b CM	263	ret = btrfs_commit_tree_roots(trans, root);
79154b1b CM	264	BUG_ON(ret);
78fae27e CM	265	cur_trans = root->fs_info->running_transaction;
78fae27e CM	266	root->fs_info->running_transaction = NULL;
0f7d52f4 CM	267	btrfs_set_super_generation(root->fs_info->disk_super,
0f7d52f4 CM	268	root->fs_info->generation + 1);
78fae27e	269	mutex_unlock(&root->fs_info->trans_mutex);
79154b1b CM	270	ret = btrfs_write_and_wait_transaction(trans, root);
	271	BUG_ON(ret);
	272
	273	write_ctree_super(trans, root);
78fae27e CM	274	btrfs_finish_extent_commit(trans, root);
78fae27e CM	275	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6 CM	276	cur_trans->commit_done = 1;
2c90e5d6 CM	277	wake_up(&cur_trans->commit_wait);
78fae27e	278	put_transaction(cur_trans);
79154b1b	279	put_transaction(cur_trans);
78fae27e	280	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	281	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b	282
0f7d52f4	283	drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
79154b1b CM	284	return ret;
	285	}
	286