From 5c3216c0460cbedd12994e584f93e0ea63a026ec Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Tue, 14 Sep 2021 15:24:49 +0300 Subject: [PATCH] qcow2-refcount: fix_l2_entry_by_zero(): also zero L2 entry bitmap We'll reuse the function to fix wrong L2 entry bitmap. Support it now. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Reviewed-by: Hanna Reitz Message-Id: <20210914122454.141075-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz --- block/qcow2-refcount.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 184b96ad63..f48c5e1b5d 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1588,7 +1588,8 @@ enum { }; /* - * Fix L2 entry by making it QCOW2_CLUSTER_ZERO_PLAIN. + * Fix L2 entry by making it QCOW2_CLUSTER_ZERO_PLAIN (or making all its present + * subclusters QCOW2_SUBCLUSTER_ZERO_PLAIN). * * This function decrements res->corruptions on success, so the caller is * responsible to increment res->corruptions prior to the call. @@ -1605,9 +1606,20 @@ static int fix_l2_entry_by_zero(BlockDriverState *bs, BdrvCheckResult *res, int idx = l2_index * (l2_entry_size(s) / sizeof(uint64_t)); uint64_t l2e_offset = l2_offset + (uint64_t)l2_index * l2_entry_size(s); int ign = active ? QCOW2_OL_ACTIVE_L2 : QCOW2_OL_INACTIVE_L2; - uint64_t l2_entry = has_subclusters(s) ? 0 : QCOW_OFLAG_ZERO; - set_l2_entry(s, l2_table, l2_index, l2_entry); + if (has_subclusters(s)) { + uint64_t l2_bitmap = get_l2_bitmap(s, l2_table, l2_index); + + /* Allocated subclusters become zero */ + l2_bitmap |= l2_bitmap << 32; + l2_bitmap &= QCOW_L2_BITMAP_ALL_ZEROES; + + set_l2_bitmap(s, l2_table, l2_index, l2_bitmap); + set_l2_entry(s, l2_table, l2_index, 0); + } else { + set_l2_entry(s, l2_table, l2_index, QCOW_OFLAG_ZERO); + } + ret = qcow2_pre_write_overlap_check(bs, ign, l2e_offset, l2_entry_size(s), false); if (metadata_overlap) {