From 915c420ddfa3eb22a0dbdb7a8e0ecf020c31961f Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 23 Dec 2011 10:17:51 +1100 Subject: [PATCH] md/bitmap: be more consistent when setting new bits in memory bitmap. For each active region corresponding to a bit in the bitmap with have a 14bit counter (and some flags). This counts number of active writes + bit in the on-disk bitmap + delay-needed. The "delay-needed" is because we always want a delay before clearing a bit. So the number here is normally number of active writes plus 2. If there have been no writes for a while, we drop to 1. If still no writes we clear the bit and drop to 0. So for consistency, when setting bit from the on-disk bitmap or by request from user-space it is best to set the counter to '2' to start with. In particular we might also set the NEEDED_MASK flag at this time, and in all other cases NEEDED_MASK is only set when the counter is 2 or more. Signed-off-by: NeilBrown --- drivers/md/bitmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index 048eec751474..cdf36b1e9aa6 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -1587,7 +1587,7 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int n } if (!*bmc) { struct page *page; - *bmc = 1 | (needed ? NEEDED_MASK : 0); + *bmc = 2 | (needed ? NEEDED_MASK : 0); bitmap_count_page(bitmap, offset, 1); page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)); set_page_attr(bitmap, page, BITMAP_PAGE_PENDING);