[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--;
		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->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)
{
	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 == 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);
	}
	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 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,
2619ba1f CM	67	(unsigned long)root->root_key.objectid,
2619ba1f CM	68	BTRFS_ROOT_TRANS_TAG);
0f7d52f4 CM	69	root->commit_root = root->node;
	70	get_bh(root->node);
	71	}
	72	root->last_trans = running_trans_id;
	73	h->transid = running_trans_id;
79154b1b CM	74	h->transaction = root->fs_info->running_transaction;
	75	h->blocks_reserved = num_blocks;
	76	h->blocks_used = 0;
	77	root->fs_info->running_transaction->use_count++;
	78	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	79	h->magic = h->magic2 = TRANS_MAGIC;
79154b1b CM	80	return h;
	81	}
	82
	83	int btrfs_end_transaction(struct btrfs_trans_handle *trans,
	84	struct btrfs_root *root)
	85	{
	86	struct btrfs_transaction *cur_trans;
d6e4a428	87
2c90e5d6 CM	88	WARN_ON(trans->magic != TRANS_MAGIC);
2c90e5d6 CM	89	WARN_ON(trans->magic2 != TRANS_MAGIC);
79154b1b CM	90	mutex_lock(&root->fs_info->trans_mutex);
79154b1b CM	91	cur_trans = root->fs_info->running_transaction;
d5719762	92	WARN_ON(cur_trans->num_writers < 1);
79154b1b CM	93	if (waitqueue_active(&cur_trans->writer_wait))
	94	wake_up(&cur_trans->writer_wait);
	95	cur_trans->num_writers--;
	96	put_transaction(cur_trans);
	97	mutex_unlock(&root->fs_info->trans_mutex);
d6025579	98	memset(trans, 0, sizeof(*trans));
2c90e5d6	99	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b CM	100	return 0;
	101	}
	102
	103
	104	int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
	105	struct btrfs_root *root)
	106	{
7cfcc17e	107	filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
79154b1b CM	108	return 0;
	109	}
	110
	111	int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
	112	struct btrfs_root *root)
	113	{
	114	int ret;
	115	u64 old_extent_block;
	116	struct btrfs_fs_info *fs_info = root->fs_info;
	117	struct btrfs_root *tree_root = fs_info->tree_root;
	118	struct btrfs_root *extent_root = fs_info->extent_root;
79154b1b	119
79154b1b CM	120	while(1) {
79154b1b CM	121	old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
7eccb903	122	if (old_extent_block == bh_blocknr(extent_root->node))
79154b1b CM	123	break;
79154b1b CM	124	btrfs_set_root_blocknr(&extent_root->root_item,
7eccb903	125	bh_blocknr(extent_root->node));
79154b1b CM	126	ret = btrfs_update_root(trans, tree_root,
	127	&extent_root->root_key,
	128	&extent_root->root_item);
	129	BUG_ON(ret);
	130	}
	131	return 0;
	132	}
	133
	134	static int wait_for_commit(struct btrfs_root *root,
	135	struct btrfs_transaction *commit)
	136	{
	137	DEFINE_WAIT(wait);
79154b1b CM	138	while(!commit->commit_done) {
	139	prepare_to_wait(&commit->commit_wait, &wait,
	140	TASK_UNINTERRUPTIBLE);
	141	if (commit->commit_done)
	142	break;
	143	mutex_unlock(&root->fs_info->trans_mutex);
	144	schedule();
	145	mutex_lock(&root->fs_info->trans_mutex);
	146	}
	147	finish_wait(&commit->commit_wait, &wait);
	148	return 0;
	149	}
	150
0f7d52f4 CM	151	struct dirty_root {
	152	struct list_head list;
	153	struct btrfs_key snap_key;
	154	struct buffer_head *commit_root;
	155	struct btrfs_root *root;
	156	};
	157
	158	int add_dirty_roots(struct btrfs_trans_handle *trans,
	159	struct radix_tree_root radix, struct list_head list)
	160	{
	161	struct dirty_root *dirty;
	162	struct btrfs_root *gang[8];
	163	struct btrfs_root *root;
	164	int i;
	165	int ret;
	166	int err;
0f7d52f4 CM	167	while(1) {
	168	ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
	169	ARRAY_SIZE(gang),
	170	BTRFS_ROOT_TRANS_TAG);
	171	if (ret == 0)
	172	break;
	173	for (i = 0; i < ret; i++) {
	174	root = gang[i];
2619ba1f CM	175	radix_tree_tag_clear(radix,
	176	(unsigned long)root->root_key.objectid,
	177	BTRFS_ROOT_TRANS_TAG);
0f7d52f4	178	if (root->commit_root == root->node) {
7eccb903	179	WARN_ON(bh_blocknr(root->node) !=
0f7d52f4 CM	180	btrfs_root_blocknr(&root->root_item));
	181	brelse(root->commit_root);
	182	root->commit_root = NULL;
	183	continue;
	184	}
	185	dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
	186	BUG_ON(!dirty);
	187	memcpy(&dirty->snap_key, &root->root_key,
	188	sizeof(root->root_key));
	189	dirty->commit_root = root->commit_root;
	190	root->commit_root = NULL;
	191	dirty->root = root;
0f7d52f4 CM	192	root->root_key.offset = root->fs_info->generation;
0f7d52f4 CM	193	btrfs_set_root_blocknr(&root->root_item,
7eccb903	194	bh_blocknr(root->node));
0f7d52f4 CM	195	err = btrfs_insert_root(trans, root->fs_info->tree_root,
	196	&root->root_key,
	197	&root->root_item);
	198	BUG_ON(err);
	199	list_add(&dirty->list, list);
	200	}
	201	}
0f7d52f4 CM	202	return 0;
	203	}
	204
	205	int drop_dirty_roots(struct btrfs_root tree_root, struct list_head list)
	206	{
	207	struct dirty_root *dirty;
	208	struct btrfs_trans_handle *trans;
	209	int ret;
	210
	211	while(!list_empty(list)) {
	212	dirty = list_entry(list->next, struct dirty_root, list);
	213	list_del_init(&dirty->list);
	214	trans = btrfs_start_transaction(tree_root, 1);
0f7d52f4 CM	215	ret = btrfs_drop_snapshot(trans, dirty->root,
	216	dirty->commit_root);
	217	BUG_ON(ret);
	218
0f7d52f4 CM	219	ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
	220	BUG_ON(ret);
	221	ret = btrfs_end_transaction(trans, tree_root);
	222	BUG_ON(ret);
	223	kfree(dirty);
	224	}
	225	return 0;
	226	}
	227
79154b1b CM	228	int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
	229	struct btrfs_root *root)
	230	{
	231	int ret = 0;
79154b1b	232	struct btrfs_transaction *cur_trans;
0f7d52f4	233	struct list_head dirty_fs_roots;
79154b1b CM	234	DEFINE_WAIT(wait);
79154b1b CM	235
0f7d52f4	236	INIT_LIST_HEAD(&dirty_fs_roots);
d6e4a428	237
79154b1b CM	238	mutex_lock(&root->fs_info->trans_mutex);
	239	if (trans->transaction->in_commit) {
	240	cur_trans = trans->transaction;
	241	trans->transaction->use_count++;
	242	btrfs_end_transaction(trans, root);
	243	ret = wait_for_commit(root, cur_trans);
	244	BUG_ON(ret);
	245	put_transaction(cur_trans);
	246	mutex_unlock(&root->fs_info->trans_mutex);
	247	return 0;
	248	}
2c90e5d6 CM	249	cur_trans = trans->transaction;
2c90e5d6 CM	250	trans->transaction->in_commit = 1;
79154b1b	251	while (trans->transaction->num_writers > 1) {
2c90e5d6	252	WARN_ON(cur_trans != trans->transaction);
79154b1b CM	253	prepare_to_wait(&trans->transaction->writer_wait, &wait,
	254	TASK_UNINTERRUPTIBLE);
	255	if (trans->transaction->num_writers <= 1)
	256	break;
	257	mutex_unlock(&root->fs_info->trans_mutex);
	258	schedule();
	259	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6	260	finish_wait(&trans->transaction->writer_wait, &wait);
79154b1b CM	261	}
79154b1b CM	262	finish_wait(&trans->transaction->writer_wait, &wait);
2c90e5d6	263	WARN_ON(cur_trans != trans->transaction);
0f7d52f4	264	add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
79154b1b CM	265	ret = btrfs_commit_tree_roots(trans, root);
79154b1b CM	266	BUG_ON(ret);
78fae27e CM	267	cur_trans = root->fs_info->running_transaction;
78fae27e CM	268	root->fs_info->running_transaction = NULL;
0f7d52f4 CM	269	btrfs_set_super_generation(root->fs_info->disk_super,
0f7d52f4 CM	270	root->fs_info->generation + 1);
78fae27e	271	mutex_unlock(&root->fs_info->trans_mutex);
79154b1b CM	272	ret = btrfs_write_and_wait_transaction(trans, root);
	273	BUG_ON(ret);
	274
	275	write_ctree_super(trans, root);
78fae27e CM	276	btrfs_finish_extent_commit(trans, root);
78fae27e CM	277	mutex_lock(&root->fs_info->trans_mutex);
2c90e5d6 CM	278	cur_trans->commit_done = 1;
2c90e5d6 CM	279	wake_up(&cur_trans->commit_wait);
78fae27e	280	put_transaction(cur_trans);
79154b1b	281	put_transaction(cur_trans);
78fae27e	282	mutex_unlock(&root->fs_info->trans_mutex);
2c90e5d6	283	kmem_cache_free(btrfs_trans_handle_cachep, trans);
79154b1b	284
0f7d52f4	285	drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
79154b1b CM	286	return ret;
	287	}
	288