From 2a217cc07005b53a55d7f197d550ea211b0e8008 Mon Sep 17 00:00:00 2001
Message-Id: <2a217cc07005b53a55d7f197d550ea211b0e8008.1379425497.git.minovotn@redhat.com>
In-Reply-To: <f5f5558c6067d2cdb77e46707b0bda1f4f885402.1379425497.git.minovotn@redhat.com>
References: <f5f5558c6067d2cdb77e46707b0bda1f4f885402.1379425497.git.minovotn@redhat.com>
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 6 Sep 2013 18:12:41 +0200
Subject: [PATCH 21/25] block: return BDRV_BLOCK_ZERO past end of backing file
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 <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit f0ad5712d5d15ff272b9e107910be4aae468fb3d)
Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
block.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index 947b1b2..2306994 100644
--- a/block.c
+++ b/block.c
@@ -2777,8 +2777,16 @@ 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;
}
--
1.7.11.7