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Commit de6c4115 authored by Miao Xie's avatar Miao Xie Committed by Josef Bacik
Browse files

Btrfs: fix unnecessary while loop when search the free space, cache 



When we find a bitmap free space entry, we may check the previous extent
entry covers the offset or not. But if we find this entry is also a bitmap
entry, we will continue to check the previous entry of the current one by
a while loop. It is unnecessary because it is impossible that the extent
entry which is in front of a bitmap entry can cover the offset of the entry
after that bitmap entry.

Signed-off-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Reviewed-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
parent de1ee92a

fs/btrfs/free-space-cache.c

+10 −20
Original line number Diff line number Diff line
@@ -1250,18 +1250,13 @@ tree_search_offset(struct btrfs_free_space_ctl *ctl, 
			 * if previous extent entry covers the offset,

			 * we should return it instead of the bitmap entry

			 */

			n = &entry->offset_index;

			while (1) {

				n = rb_prev(n);

				if (!n)

					break;

			n = rb_prev(&entry->offset_index);

			if (n) {

				prev = rb_entry(n, struct btrfs_free_space,

						offset_index);

				if (!prev->bitmap) {

					if (prev->offset + prev->bytes > offset)

				if (!prev->bitmap &&

				    prev->offset + prev->bytes > offset)

					entry = prev;

					break;

				}

			}

		}

		return entry;
@@ -1287,18 +1282,13 @@ tree_search_offset(struct btrfs_free_space_ctl *ctl, 
	}



	if (entry->bitmap) {

		n = &entry->offset_index;

		while (1) {

			n = rb_prev(n);

			if (!n)

				break;

		n = rb_prev(&entry->offset_index);

		if (n) {

			prev = rb_entry(n, struct btrfs_free_space,

					offset_index);

			if (!prev->bitmap) {

				if (prev->offset + prev->bytes > offset)

			if (!prev->bitmap &&

			    prev->offset + prev->bytes > offset)

				return prev;

				break;

			}

		}

		if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)

			return entry;