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Commit f9295749 authored by Chris Mason's avatar Chris Mason
Browse files

btrfs_start_transaction: wait for commits in progress to finish 



btrfs_commit_transaction has to loop waiting for any writers in the
transaction to finish before it can proceed.  btrfs_start_transaction
should be polite and not join a transaction that is in the process
of being finished off.

There are a few places that can't wait, basically the ones doing IO that
might be needed to finish the transaction.  For them, btrfs_join_transaction
is added.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent dbe674a9

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -513,6 +513,7 @@ struct btrfs_fs_info { 
	u64 alloc_start;

	struct btrfs_transaction *running_transaction;

	wait_queue_head_t transaction_throttle;

	wait_queue_head_t transaction_wait;

	struct btrfs_super_block super_copy;

	struct btrfs_super_block super_for_commit;

	struct block_device *__bdev;

fs/btrfs/disk-io.c

+1 −0
Original line number Diff line number Diff line
@@ -1291,6 +1291,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, 
	mutex_init(&fs_info->cleaner_mutex);

	mutex_init(&fs_info->volume_mutex);

	init_waitqueue_head(&fs_info->transaction_throttle);

	init_waitqueue_head(&fs_info->transaction_wait);



#if 0

	ret = add_hasher(fs_info, "crc32c");

fs/btrfs/file.c

+1 −1
Original line number Diff line number Diff line
@@ -251,7 +251,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
	end_of_last_block = start_pos + num_bytes - 1;



	lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);

	trans = btrfs_start_transaction(root, 1);

	trans = btrfs_join_transaction(root, 1);

	if (!trans) {

		err = -ENOMEM;

		goto out_unlock;

fs/btrfs/inode.c

+5 −5
Original line number Diff line number Diff line
@@ -116,7 +116,7 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end) 
	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;

	int ret = 0;



	trans = btrfs_start_transaction(root, 1);

	trans = btrfs_join_transaction(root, 1);

	BUG_ON(!trans);

	btrfs_set_trans_block_group(trans, inode);
@@ -502,7 +502,7 @@ int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end, 
		return 0;

	}



	trans = btrfs_start_transaction(root, 1);

	trans = btrfs_join_transaction(root, 1);



	ordered_extent = btrfs_lookup_ordered_extent(inode, start);

	BUG_ON(!ordered_extent);
@@ -1812,7 +1812,7 @@ int btrfs_write_inode(struct inode *inode, int wait) 
	int ret = 0;



	if (wait) {

		trans = btrfs_start_transaction(root, 1);

		trans = btrfs_join_transaction(root, 1);

		btrfs_set_trans_block_group(trans, inode);

		ret = btrfs_commit_transaction(trans, root);

	}
@@ -1830,7 +1830,7 @@ void btrfs_dirty_inode(struct inode *inode) 
	struct btrfs_root *root = BTRFS_I(inode)->root;

	struct btrfs_trans_handle *trans;



	trans = btrfs_start_transaction(root, 1);

	trans = btrfs_join_transaction(root, 1);

	btrfs_set_trans_block_group(trans, inode);

	btrfs_update_inode(trans, root, inode);

	btrfs_end_transaction(trans, root);
@@ -2395,7 +2395,7 @@ struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page, 
				free_extent_map(em);

				em = NULL;

				btrfs_release_path(root, path);

				trans = btrfs_start_transaction(root, 1);

				trans = btrfs_join_transaction(root, 1);

				goto again;

			}

			write_extent_buffer(leaf, map + pg_offset, ptr,

fs/btrfs/transaction.c

+40 −3
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ static noinline int join_transaction(struct btrfs_root *root) 
		init_waitqueue_head(&cur_trans->writer_wait);

		init_waitqueue_head(&cur_trans->commit_wait);

		cur_trans->in_commit = 0;

		cur_trans->blocked = 0;

		cur_trans->use_count = 1;

		cur_trans->commit_done = 0;

		cur_trans->start_time = get_seconds();
@@ -99,14 +100,36 @@ static noinline int record_root_in_trans(struct btrfs_root *root) 
	return 0;

}



struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,

						   int num_blocks)

struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,

					     int num_blocks, int join)

{

	struct btrfs_trans_handle *h =

		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);

	struct btrfs_transaction *cur_trans;

	int ret;



	mutex_lock(&root->fs_info->trans_mutex);

	cur_trans = root->fs_info->running_transaction;

	if (cur_trans && cur_trans->blocked && !join) {

		DEFINE_WAIT(wait);

		cur_trans->use_count++;

		while(1) {

			prepare_to_wait(&root->fs_info->transaction_wait, &wait,

					TASK_UNINTERRUPTIBLE);

			if (cur_trans->blocked) {

				mutex_unlock(&root->fs_info->trans_mutex);

				schedule();

				mutex_lock(&root->fs_info->trans_mutex);

				finish_wait(&root->fs_info->transaction_wait,

					    &wait);

			} else {

				finish_wait(&root->fs_info->transaction_wait,

					    &wait);

				break;

			}

		}

		put_transaction(cur_trans);

	}

	ret = join_transaction(root);

	BUG_ON(ret);
@@ -123,6 +146,17 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 
	return h;

}



struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,

						   int num_blocks)

{

	return start_transaction(root, num_blocks, 0);

}

struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,

						   int num_blocks)

{

	return start_transaction(root, num_blocks, 1);

}



static noinline int wait_for_commit(struct btrfs_root *root,

				    struct btrfs_transaction *commit)

{
@@ -156,7 +190,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 
	if (waitqueue_active(&cur_trans->writer_wait))

		wake_up(&cur_trans->writer_wait);



	if (cur_trans->in_commit && throttle) {

	if (0 && cur_trans->in_commit && throttle) {

		DEFINE_WAIT(wait);

		mutex_unlock(&root->fs_info->trans_mutex);

		prepare_to_wait(&root->fs_info->transaction_throttle, &wait,
@@ -617,6 +651,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 


printk("commit trans %Lu\n", trans->transid);

	trans->transaction->in_commit = 1;

	trans->transaction->blocked = 1;

	cur_trans = trans->transaction;

	if (cur_trans->list.prev != &root->fs_info->trans_list) {

		prev_trans = list_entry(cur_trans->list.prev,
@@ -684,7 +719,9 @@ printk("commit trans %Lu\n", trans->transid); 


	btrfs_copy_pinned(root, pinned_copy);



	trans->transaction->blocked = 0;

	wake_up(&root->fs_info->transaction_throttle);

	wake_up(&root->fs_info->transaction_wait);



	mutex_unlock(&root->fs_info->trans_mutex);

	ret = btrfs_write_and_wait_transaction(trans, root);