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authorNeilBrown <neilb@suse.de>2011-12-22 23:17:51 (GMT)
committerNeilBrown <neilb@suse.de>2011-12-22 23:17:51 (GMT)
commit915c420ddfa3eb22a0dbdb7a8e0ecf020c31961f (patch)
tree24915c8f3380e390130d1d437389b5cb805c28fd /drivers/md
parent38059ec2bd2ce9e4709f49f34795aa0944287908 (diff)
downloadlinux-915c420ddfa3eb22a0dbdb7a8e0ecf020c31961f.tar.xz
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 <neilb@suse.de>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/bitmap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 048eec7..cdf36b1 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);