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| author | Eric Blake | 2018-10-29 21:23:17 +0100 |
|---|---|---|
| committer | John Snow | 2018-10-29 21:23:17 +0100 |
| commit | d1dde7149e376d72b422a529ec4bf3ed47f3ba30 (patch) | |
| tree | cb9309127c2851e6e13394a4253fcb235d46873b /util/hbitmap.c | |
| parent | nbd: forbid use of frozen bitmaps (diff) | |
| download | qemu-d1dde7149e376d72b422a529ec4bf3ed47f3ba30.tar.gz qemu-d1dde7149e376d72b422a529ec4bf3ed47f3ba30.tar.xz qemu-d1dde7149e376d72b422a529ec4bf3ed47f3ba30.zip | |
bitmap: Update count after a merge
We need an accurate count of the number of bits set in a bitmap
after a merge. In particular, since the merge operation short-circuits
a merge from an empty source, if you have bitmaps A, B, and C where
B started empty, then merge C into B, and B into A, an inaccurate
count meant that A did not get the contents of C.
In the worst case, we may falsely regard the bitmap as empty when
it has had new writes merged into it.
Fixes: be58721db
CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20181002233314.30159-1-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Diffstat (limited to 'util/hbitmap.c')
| -rw-r--r-- | util/hbitmap.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/util/hbitmap.c b/util/hbitmap.c index d5aca5159f..8d402c59d9 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -759,6 +759,9 @@ bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result) } } + /* Recompute the dirty count */ + result->count = hb_count_between(result, 0, result->size - 1); + return true; } |