From de6c4115a297d4bbf178aca9948c3539f89c9caa Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Thu, 18 Oct 2012 08:18:01 +0000 Subject: [PATCH] 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: Miao Xie Reviewed-by: Liu Bo Signed-off-by: Chris Mason --- fs/btrfs/free-space-cache.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 1027b854b90c..557502ca1a2a 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -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) - entry = prev; - break; - } + if (!prev->bitmap && + prev->offset + prev->bytes > offset) + entry = prev; } } 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) - return prev; - break; - } + if (!prev->bitmap && + prev->offset + prev->bytes > offset) + return prev; } if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset) return entry; -- 2.20.1