Commit 52ee28d2 authored Jul 11, 2013 by Liu Bo Committed by Chris Mason Sep 01, 2013

Btrfs: make free space caching faster with many non-inline extent references



So to cache free space, we iterate every extent item to gather free space info.

When we have say 10,000 non-inline extent refs(such as BTRFS_EXTENT_DATA_REF),
it takes quite a long time, and since inline extent refs and non-inline ones have
same objectid in their keys, we can just re-search the tree with the next address
to skip non-inline references.

(This is found by dedup feature because dedup extents can end up with many
non-inline extent refs.)

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

parent ee3441b4

fs/btrfs/extent-tree.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -420,6 +420,7 @@ static noinline void caching_thread(struct btrfs_work *work)
		/* need to make sure the commit_root doesn't disappear */
		down_read(&fs_info->extent_commit_sem);

		next:
		ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
		if (ret < 0)
		goto err;
		@@ -459,6 +460,16 @@ static noinline void caching_thread(struct btrfs_work *work)
		continue;
		}

		if (key.objectid < last) {
		key.objectid = last;
		key.offset = 0;
		key.type = BTRFS_EXTENT_ITEM_KEY;

		caching_ctl->progress = last;
		btrfs_release_path(path);
		goto next;
		}

		if (key.objectid < block_group->key.objectid) {
		path->slots[0]++;
		continue;