From a78a1a48cd1a2e86f23f113bb05e2d3dd8ae0bf6 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Tue, 15 Jan 2019 18:26:50 -0500 Subject: dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area The function alters bdrv_dirty_iter_next_area(), which is wrong and less efficient (see further commit "block/mirror: fix and improve do_sync_target_write" for description). Signed-off-by: Vladimir Sementsov-Ogievskiy --- util/hbitmap.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) (limited to 'util') diff --git a/util/hbitmap.c b/util/hbitmap.c index 09b3719e44..fa356522c4 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -246,6 +246,45 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, uint64_t count) return res; } +bool hbitmap_next_dirty_area(const HBitmap *hb, uint64_t *start, + uint64_t *count) +{ + HBitmapIter hbi; + int64_t firt_dirty_off, area_end; + uint32_t granularity = 1UL << hb->granularity; + uint64_t end; + + if (*start >= hb->orig_size || *count == 0) { + return false; + } + + end = *count > hb->orig_size - *start ? hb->orig_size : *start + *count; + + hbitmap_iter_init(&hbi, hb, *start); + firt_dirty_off = hbitmap_iter_next(&hbi, false); + + if (firt_dirty_off < 0 || firt_dirty_off >= end) { + return false; + } + + if (firt_dirty_off + granularity >= end) { + area_end = end; + } else { + area_end = hbitmap_next_zero(hb, firt_dirty_off + granularity, + end - firt_dirty_off - granularity); + if (area_end < 0) { + area_end = end; + } + } + + if (firt_dirty_off > *start) { + *start = firt_dirty_off; + } + *count = area_end - *start; + + return true; +} + bool hbitmap_empty(const HBitmap *hb) { return hb->count == 0; -- cgit v1.2.3