Commit b1d4d5d1 authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: remove the changed list for backref cache 



Now that we're not updating the backref cache when we switch transids we
can remove the changed list.

We're going to keep the new_bytenr field because it serves as a good
sanity check for the backref cache and relocation, and can prevent us
from making extent tree corruption worse.

Reviewed-by: default avatarBoris Burkov <boris@bur.io>
Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 6a4730b3

fs/btrfs/backref.c

+0 −2
Original line number Diff line number Diff line
@@ -3022,7 +3022,6 @@ void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info, 
	cache->rb_root = RB_ROOT;

	for (i = 0; i < BTRFS_MAX_LEVEL; i++)

		INIT_LIST_HEAD(&cache->pending[i]);

	INIT_LIST_HEAD(&cache->changed);

	INIT_LIST_HEAD(&cache->detached);

	INIT_LIST_HEAD(&cache->leaves);

	INIT_LIST_HEAD(&cache->pending_edge);
@@ -3190,7 +3189,6 @@ void btrfs_backref_release_cache(struct btrfs_backref_cache *cache) 
	}

	ASSERT(list_empty(&cache->pending_edge));

	ASSERT(list_empty(&cache->useless_node));

	ASSERT(list_empty(&cache->changed));

	ASSERT(list_empty(&cache->detached));

	ASSERT(RB_EMPTY_ROOT(&cache->rb_root));

	ASSERT(!cache->nr_nodes);

fs/btrfs/backref.h

+0 −2
Original line number Diff line number Diff line
@@ -393,8 +393,6 @@ struct btrfs_backref_cache { 
	struct list_head pending[BTRFS_MAX_LEVEL];

	/* List of backref nodes with no child node */

	struct list_head leaves;

	/* List of blocks that have been COWed in current transaction */

	struct list_head changed;

	/* List of detached backref node. */

	struct list_head detached;

fs/btrfs/relocation.c

+8 −14
Original line number Diff line number Diff line
@@ -2113,14 +2113,13 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, 
		if (next->new_bytenr != root->node->start) {

			/*

			 * We just created the reloc root, so we shouldn't have

			 * ->new_bytenr set and this shouldn't be in the changed

			 *  list.  If it is then we have multiple roots pointing

			 *  at the same bytenr which indicates corruption, or

			 *  we've made a mistake in the backref walking code.

			 * ->new_bytenr set yet. If it is then we have multiple

			 *  roots pointing at the same bytenr which indicates

			 *  corruption, or we've made a mistake in the backref

			 *  walking code.

			 */

			ASSERT(next->new_bytenr == 0);

			ASSERT(list_empty(&next->list));

			if (next->new_bytenr || !list_empty(&next->list)) {

			if (next->new_bytenr) {

				btrfs_err(trans->fs_info,

	"bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",

					  node->bytenr, next->bytenr);
@@ -2131,8 +2130,6 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, 
			btrfs_put_root(next->root);

			next->root = btrfs_grab_root(root);

			ASSERT(next->root);

			list_add_tail(&next->list,

				      &rc->backref_cache.changed);

			mark_block_processed(rc, next);

			break;

		}
@@ -2442,7 +2439,7 @@ static int do_relocation(struct btrfs_trans_handle *trans, 


	if (!ret && node->pending) {

		btrfs_backref_drop_node_buffer(node);

		list_move_tail(&node->list, &rc->backref_cache.changed);

		list_del_init(&node->list);

		node->pending = 0;

	}
@@ -2605,8 +2602,7 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, 
			/*

			 * This block was the root block of a root, and this is

			 * the first time we're processing the block and thus it

			 * should not have had the ->new_bytenr modified and

			 * should have not been included on the changed list.

			 * should not have had the ->new_bytenr modified.

			 *

			 * However in the case of corruption we could have

			 * multiple refs pointing to the same block improperly,
@@ -2616,8 +2612,7 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, 
			 * normal user in the case of corruption.

			 */

			ASSERT(node->new_bytenr == 0);

			ASSERT(list_empty(&node->list));

			if (node->new_bytenr || !list_empty(&node->list)) {

			if (node->new_bytenr) {

				btrfs_err(root->fs_info,

				  "bytenr %llu has improper references to it",

					  node->bytenr);
@@ -2640,7 +2635,6 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, 
			btrfs_put_root(node->root);

			node->root = btrfs_grab_root(root);

			ASSERT(node->root);

			list_add_tail(&node->list, &rc->backref_cache.changed);

		} else {

			path->lowest_level = node->level;

			if (root == root->fs_info->chunk_root)