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[Qemu-devel] [PATCH 1/1] block/vpc.c: Detect too-large vpc file
From: |
Serge E. Hallyn |
Subject: |
[Qemu-devel] [PATCH 1/1] block/vpc.c: Detect too-large vpc file |
Date: |
Mon, 25 Jul 2011 18:34:35 +0000 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
VHD files technically can be up to 2Tb, but virtual pc is limited
to 127G. Currently qemu-img refused to create vpc files > 127G,
but it is failing to return error when converting from a non-vpc
VHD file which is >127G. It returns success, but creates a truncated
converted image. Also, qemu-img info claims the vpc file is 127G
(and clean).
This patch detects a too-large vpc file and returns -EFBIG. Without
this patch,
=============================================================
address@hidden:~/qemu-fixed# qemu-img info /mnt/140g-dynamic.vhd
image: /mnt/140g-dynamic.vhd
file format: vpc
virtual size: 127G (136899993600 bytes)
disk size: 284K
address@hidden:~/qemu-fixed# qemu-img convert -f vpc -O raw
/mnt/140g-dynamic.vhd /mnt/y
address@hidden:~/qemu-fixed# echo $?
0
address@hidden:~/qemu-fixed# qemu-img info /mnt/y
image: /mnt/y
file format: raw
virtual size: 127G (136899993600 bytes)
disk size: 0
=============================================================
(The 140G image was truncated with no warning or error.)
With the patch, I get:
=============================================================
address@hidden:~/qemu-fixed# ./qemu-img info /mnt/140g-dynamic.vhd
qemu-img: Could not open '/mnt/140g-dynamic.vhd': File too large
address@hidden:~/qemu-fixed# ./qemu-img convert -f vpc -O raw
/mnt/140g-dynamic.vhd /mnt/y
qemu-img: Could not open '/mnt/140g-dynamic.vhd': File too large
qemu-img: Could not open '/mnt/140g-dynamic.vhd'
=============================================================
See https://bugs.launchpad.net/qemu/+bug/814222 for details.
Signed-off-by: Serge Hallyn <address@hidden>
---
block/vpc.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/block/vpc.c b/block/vpc.c
index 56865da..fdd5236 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -156,6 +156,7 @@ static int vpc_open(BlockDriverState *bs, int flags)
struct vhd_dyndisk_header* dyndisk_header;
uint8_t buf[HEADER_SIZE];
uint32_t checksum;
+ int err = -1;
if (bdrv_pread(bs->file, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE)
goto fail;
@@ -176,6 +177,11 @@ static int vpc_open(BlockDriverState *bs, int flags)
bs->total_sectors = (int64_t)
be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
+ if (bs->total_sectors >= 65535 * 16 * 255) {
+ err = -EFBIG;
+ goto fail;
+ }
+
if (bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), buf,
HEADER_SIZE)
!= HEADER_SIZE)
goto fail;
@@ -222,7 +228,7 @@ static int vpc_open(BlockDriverState *bs, int flags)
return 0;
fail:
- return -1;
+ return err;
}
/*
--
1.7.5.4
- [Qemu-devel] [PATCH 1/1] block/vpc.c: Detect too-large vpc file,
Serge E. Hallyn <=