From 231ea3db5b4c6b9de25fa62b2e6c39ebc4987a6f Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 18 Oct 2013 08:14:41 +0200 Subject: [PATCH 16/81] block: return BDRV_BLOCK_ZERO past end of backing file RH-Author: Paolo Bonzini Message-id: <1382084091-16636-17-git-send-email-pbonzini@redhat.com> Patchwork-id: 54999 O-Subject: [RHEL 7.0 qemu-kvm PATCH 16/26] block: return BDRV_BLOCK_ZERO past end of backing file Bugzilla: 989646 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Max Reitz RH-Acked-by: Kevin Wolf If the sectors are unallocated and we are past the end of the backing file, they will read as zero. Signed-off-by: Paolo Bonzini (cherry picked from commit f0ad5712d5d15ff272b9e107910be4aae468fb3d) --- block.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) Signed-off-by: Miroslav Rezanina --- block.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index 00bc3b2..36a2f24 100644 --- a/block.c +++ b/block.c @@ -3068,8 +3068,16 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, return ret; } - if (!(ret & BDRV_BLOCK_DATA) && bdrv_has_zero_init(bs)) { - ret |= BDRV_BLOCK_ZERO; + if (!(ret & BDRV_BLOCK_DATA)) { + if (bdrv_has_zero_init(bs)) { + ret |= BDRV_BLOCK_ZERO; + } else { + BlockDriverState *bs2 = bs->backing_hd; + int64_t length2 = bdrv_getlength(bs2); + if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) { + ret |= BDRV_BLOCK_ZERO; + } + } } return ret; } -- 1.7.1