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Commit 1cc127b5 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Add a thread pool just for submit_bio



If a bio submission is after a lock holder waiting for the bio
on the work queue, it is possible to deadlock.  Move the bios
into their own pool.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent df5b5520
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+4 −0
Original line number Diff line number Diff line
@@ -529,9 +529,13 @@ struct btrfs_fs_info {
	 * can run with FS locks held, and the writers may be waiting for
	 * those locks.  We don't want ordering in the pending list to cause
	 * deadlocks, and so the two are serviced separately.
	 *
	 * A third pool does submit_bio to avoid deadlocking with the other
	 * two
	 */
	struct btrfs_workers workers;
	struct btrfs_workers endio_workers;
	struct btrfs_workers submit_workers;
	int thread_pool_size;

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
+4 −0
Original line number Diff line number Diff line
@@ -1233,8 +1233,10 @@ struct btrfs_root *open_ctree(struct super_block *sb,
	 * cannot dynamically grow.
	 */
	btrfs_init_workers(&fs_info->workers, fs_info->thread_pool_size);
	btrfs_init_workers(&fs_info->submit_workers, fs_info->thread_pool_size);
	btrfs_init_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
	btrfs_start_workers(&fs_info->workers, 1);
	btrfs_start_workers(&fs_info->submit_workers, 1);
	btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);


@@ -1343,6 +1345,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
	extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
	btrfs_stop_workers(&fs_info->workers);
	btrfs_stop_workers(&fs_info->endio_workers);
	btrfs_stop_workers(&fs_info->submit_workers);
fail_iput:
	iput(fs_info->btree_inode);
fail:
@@ -1597,6 +1600,7 @@ int close_ctree(struct btrfs_root *root)

	btrfs_stop_workers(&fs_info->workers);
	btrfs_stop_workers(&fs_info->endio_workers);
	btrfs_stop_workers(&fs_info->submit_workers);

	iput(fs_info->btree_inode);
#if 0
+2 −1
Original line number Diff line number Diff line
@@ -2112,7 +2112,8 @@ int schedule_bio(struct btrfs_root *root, struct btrfs_device *device,
	spin_unlock(&device->io_lock);

	if (should_queue)
		btrfs_queue_worker(&root->fs_info->workers, &device->work);
		btrfs_queue_worker(&root->fs_info->submit_workers,
				   &device->work);
	return 0;
}