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author | NeilBrown <neilb@suse.de> | 2011-12-22 23:17:51 (GMT) |
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committer | NeilBrown <neilb@suse.de> | 2011-12-22 23:17:51 (GMT) |
commit | 915c420ddfa3eb22a0dbdb7a8e0ecf020c31961f (patch) | |
tree | 24915c8f3380e390130d1d437389b5cb805c28fd /drivers/md/bitmap.c | |
parent | 38059ec2bd2ce9e4709f49f34795aa0944287908 (diff) | |
download | linux-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/bitmap.c')
-rw-r--r-- | drivers/md/bitmap.c | 2 |
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); |