[PULL v2 10/11] nbd/server: use bdrv_dirty_bitmap_next_dirty_area

From: Vladimir Sementsov-Ogievskiy <vsementsov(a)virtuozzo.com&gt; Use bdrv_dirty_bitmap_next_dirty_area for bitmap_to_extents. Since bdrv_dirty_bitmap_next_dirty_area is very accurate in its interface, we'll never exceed requested region with last chunk. So, we don't need dont_fragment, and bitmap_to_extents() interface becomes clean enough to not require any comment. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)virtuozzo.com&gt; Reviewed-by: Eric Blake <eblake(a)redhat.com&gt; Message-id: 20200205112041.6003-10-vsementsov(a)virtuozzo.com Signed-off-by: John Snow <jsnow(a)redhat.com&gt; --- nbd/server.c | 59 +++++++++++++++++----------------------------------- 1 file changed, 19 insertions(+), 40 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index f90bb33a75..02b1ed0801 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -2068,57 +2068,36 @@ static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, return nbd_co_send_extents(client, handle, ea, last, context_id, errp); } -/* - * Populate @ea from a dirty bitmap. Unless @dont_fragment, the - * final extent may exceed the original @length. - */ +/* Populate @ea from a dirty bitmap. */ static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, uint64_t length, - NBDExtentArray *ea, bool dont_fragment) + NBDExtentArray *es) { - uint64_t begin = offset, end = offset; - uint64_t overall_end = offset + length; - BdrvDirtyBitmapIter *it; - bool dirty; + int64_t start, dirty_start, dirty_count; + int64_t end = offset + length; + bool full = false; bdrv_dirty_bitmap_lock(bitmap); - it = bdrv_dirty_iter_new(bitmap); - dirty = bdrv_dirty_bitmap_get_locked(bitmap, offset); - - while (begin < overall_end) { - bool next_dirty = !dirty; - - if (dirty) { - end = bdrv_dirty_bitmap_next_zero(bitmap, begin, INT64_MAX); - } else { - bdrv_set_dirty_iter(it, begin); - end = bdrv_dirty_iter_next(it); - } - if (end == -1 || end - begin > UINT32_MAX) { - /* Cap to an aligned value < 4G beyond begin. */ - end = MIN(bdrv_dirty_bitmap_size(bitmap), - begin + UINT32_MAX + 1 - - bdrv_dirty_bitmap_granularity(bitmap)); - next_dirty = dirty; - } - if (dont_fragment && end > overall_end) { - end = overall_end; - } - - if (nbd_extent_array_add(ea, end - begin, - dirty ? NBD_STATE_DIRTY : 0) < 0) { + for (start = offset; + bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX, + &dirty_start, &dirty_count); + start = dirty_start + dirty_count) + { + if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || + (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) + { + full = true; break; } - begin = end; - dirty = next_dirty; } - bdrv_dirty_iter_free(it); + if (!full) { + /* last non dirty extent */ + nbd_extent_array_add(es, end - start, 0); + } bdrv_dirty_bitmap_unlock(bitmap); - - assert(offset < end); } static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, @@ -2129,7 +2108,7 @@ static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); - bitmap_to_extents(bitmap, offset, length, ea, dont_fragment); + bitmap_to_extents(bitmap, offset, length, ea); return nbd_co_send_extents(client, handle, ea, last, context_id, errp); } -- 2.21.1