Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8cef4e16 authored by Yan, Zheng's avatar Yan, Zheng Committed by Chris Mason
Browse files

Btrfs: Avoid superfluous tree-log writeout 



We allow two log transactions at a time, but use same flag
to mark dirty tree-log btree blocks. So we may flush dirty
blocks belonging to newer log transaction when committing a
log transaction. This patch fixes the issue by using two
flags to mark dirty tree-log btree blocks.

Signed-off-by: default avatarYan Zheng <zheng.yan@oracle.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 22763c5c

fs/btrfs/disk-io.c

+3 −3
Original line number Diff line number Diff line
@@ -980,12 +980,12 @@ int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans, 


	while (1) {

		ret = find_first_extent_bit(&log_root_tree->dirty_log_pages,

				    0, &start, &end, EXTENT_DIRTY);

				0, &start, &end, EXTENT_DIRTY | EXTENT_NEW);

		if (ret)

			break;



		clear_extent_dirty(&log_root_tree->dirty_log_pages,

				   start, end, GFP_NOFS);

		clear_extent_bits(&log_root_tree->dirty_log_pages, start, end,

				  EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS);

	}

	eb = fs_info->log_root_tree->node;

fs/btrfs/extent-tree.c

+10 −2
Original line number Diff line number Diff line
@@ -4919,8 +4919,16 @@ struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans, 
	btrfs_set_buffer_uptodate(buf);



	if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {

		/*

		 * we allow two log transactions at a time, use different

		 * EXENT bit to differentiate dirty pages.

		 */

		if (root->log_transid % 2 == 0)

			set_extent_dirty(&root->dirty_log_pages, buf->start,

					buf->start + buf->len - 1, GFP_NOFS);

		else

			set_extent_new(&root->dirty_log_pages, buf->start,

					buf->start + buf->len - 1, GFP_NOFS);

	} else {

		set_extent_dirty(&trans->transaction->dirty_pages, buf->start,

			 buf->start + buf->len - 1, GFP_NOFS);

fs/btrfs/transaction.c

+11 −10
Original line number Diff line number Diff line
@@ -354,7 +354,7 @@ int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, 
 * those extents are sent to disk but does not wait on them

 */

int btrfs_write_marked_extents(struct btrfs_root *root,

			       struct extent_io_tree *dirty_pages)

			       struct extent_io_tree *dirty_pages, int mark)

{

	int ret;

	int err = 0;
@@ -367,7 +367,7 @@ int btrfs_write_marked_extents(struct btrfs_root *root, 


	while (1) {

		ret = find_first_extent_bit(dirty_pages, start, &start, &end,

					    EXTENT_DIRTY);

					    mark);

		if (ret)

			break;

		while (start <= end) {
@@ -413,7 +413,7 @@ int btrfs_write_marked_extents(struct btrfs_root *root, 
 * on all the pages and clear them from the dirty pages state tree

 */

int btrfs_wait_marked_extents(struct btrfs_root *root,

			      struct extent_io_tree *dirty_pages)

			      struct extent_io_tree *dirty_pages, int mark)

{

	int ret;

	int err = 0;
@@ -425,12 +425,12 @@ int btrfs_wait_marked_extents(struct btrfs_root *root, 
	unsigned long index;



	while (1) {

		ret = find_first_extent_bit(dirty_pages, 0, &start, &end,

					    EXTENT_DIRTY);

		ret = find_first_extent_bit(dirty_pages, start, &start, &end,

					    mark);

		if (ret)

			break;



		clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);

		clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);

		while (start <= end) {

			index = start >> PAGE_CACHE_SHIFT;

			start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
@@ -460,13 +460,13 @@ int btrfs_wait_marked_extents(struct btrfs_root *root, 
 * those extents are on disk for transaction or log commit

 */

int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,

					struct extent_io_tree *dirty_pages)

				struct extent_io_tree *dirty_pages, int mark)

{

	int ret;

	int ret2;



	ret = btrfs_write_marked_extents(root, dirty_pages);

	ret2 = btrfs_wait_marked_extents(root, dirty_pages);

	ret = btrfs_write_marked_extents(root, dirty_pages, mark);

	ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);

	return ret || ret2;

}
@@ -479,7 +479,8 @@ int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, 
		return filemap_write_and_wait(btree_inode->i_mapping);

	}

	return btrfs_write_and_wait_marked_extents(root,

					   &trans->transaction->dirty_pages);

					   &trans->transaction->dirty_pages,

					   EXTENT_DIRTY);

}



/*

fs/btrfs/transaction.h

+3 −3
Original line number Diff line number Diff line
@@ -107,10 +107,10 @@ void btrfs_throttle(struct btrfs_root *root); 
int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,

				struct btrfs_root *root);

int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,

					struct extent_io_tree *dirty_pages);

				struct extent_io_tree *dirty_pages, int mark);

int btrfs_write_marked_extents(struct btrfs_root *root,

					struct extent_io_tree *dirty_pages);

				struct extent_io_tree *dirty_pages, int mark);

int btrfs_wait_marked_extents(struct btrfs_root *root,

					struct extent_io_tree *dirty_pages);

				struct extent_io_tree *dirty_pages, int mark);

int btrfs_transaction_in_commit(struct btrfs_fs_info *info);

#endif

fs/btrfs/tree-log.c

+20 −13
Original line number Diff line number Diff line
@@ -1977,10 +1977,11 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, 
{

	int index1;

	int index2;

	int mark;

	int ret;

	struct btrfs_root *log = root->log_root;

	struct btrfs_root *log_root_tree = root->fs_info->log_root_tree;

	u64 log_transid = 0;

	unsigned long log_transid = 0;



	mutex_lock(&root->log_mutex);

	index1 = root->log_transid % 2;
@@ -2014,24 +2015,29 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, 
		goto out;

	}



	log_transid = root->log_transid;

	if (log_transid % 2 == 0)

		mark = EXTENT_DIRTY;

	else

		mark = EXTENT_NEW;



	/* we start IO on  all the marked extents here, but we don't actually

	 * wait for them until later.

	 */

	ret = btrfs_write_marked_extents(log, &log->dirty_log_pages);

	ret = btrfs_write_marked_extents(log, &log->dirty_log_pages, mark);

	BUG_ON(ret);



	btrfs_set_root_node(&log->root_item, log->node);



	root->log_batch = 0;

	log_transid = root->log_transid;

	root->log_transid++;

	log->log_transid = root->log_transid;

	root->log_start_pid = 0;

	smp_mb();

	/*

	 * log tree has been flushed to disk, new modifications of

	 * the log will be written to new positions. so it's safe to

	 * allow log writers to go in.

	 * IO has been started, blocks of the log tree have WRITTEN flag set

	 * in their headers. new modifications of the log will be written to

	 * new positions. so it's safe to allow log writers to go in.

	 */

	mutex_unlock(&root->log_mutex);
@@ -2052,7 +2058,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, 


	index2 = log_root_tree->log_transid % 2;

	if (atomic_read(&log_root_tree->log_commit[index2])) {

		btrfs_wait_marked_extents(log, &log->dirty_log_pages);

		btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);

		wait_log_commit(trans, log_root_tree,

				log_root_tree->log_transid);

		mutex_unlock(&log_root_tree->log_mutex);
@@ -2072,16 +2078,17 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, 
	 * check the full commit flag again

	 */

	if (root->fs_info->last_trans_log_full_commit == trans->transid) {

		btrfs_wait_marked_extents(log, &log->dirty_log_pages);

		btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);

		mutex_unlock(&log_root_tree->log_mutex);

		ret = -EAGAIN;

		goto out_wake_log_root;

	}



	ret = btrfs_write_and_wait_marked_extents(log_root_tree,

				&log_root_tree->dirty_log_pages);

				&log_root_tree->dirty_log_pages,

				EXTENT_DIRTY | EXTENT_NEW);

	BUG_ON(ret);

	btrfs_wait_marked_extents(log, &log->dirty_log_pages);

	btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);



	btrfs_set_super_log_root(&root->fs_info->super_for_commit,

				log_root_tree->node->start);
@@ -2147,12 +2154,12 @@ int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root) 


	while (1) {

		ret = find_first_extent_bit(&log->dirty_log_pages,

				    0, &start, &end, EXTENT_DIRTY);

				0, &start, &end, EXTENT_DIRTY | EXTENT_NEW);

		if (ret)

			break;



		clear_extent_dirty(&log->dirty_log_pages,

				   start, end, GFP_NOFS);

		clear_extent_bits(&log->dirty_log_pages, start, end,

				  EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS);

	}



	if (log->log_transid > 0) {