From 8ac835bec90a56f37e2f555ef6c5e06c3b5ab1ac Mon Sep 17 00:00:00 2001
Message-Id: <8ac835bec90a56f37e2f555ef6c5e06c3b5ab1ac.1380542680.git.minovotn@redhat.com>
From: Asias He <asias@redhat.com>
Date: Thu, 12 Sep 2013 07:23:00 +0200
Subject: [PATCH] block: Introduce bs->zero_beyond_eof
RH-Author: Asias He <asias@redhat.com>
Message-id: <1378970580-12500-1-git-send-email-asias@redhat.com>
Patchwork-id: 54321
O-Subject: [RHEL6.5 qemu-kvm PATCH] block: Introduce bs->zero_beyond_eof
Bugzilla: 1007224
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Markus Armbruster <armbru@redhat.com>
BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1007224
Brew: https://brewweb.devel.redhat.com/taskinfo?taskID=6275709
This is the manual backport of 0d51b4debee6fb322751a57097a1d675c7a7c38d:
In 4146b46c42e0989cb5842e04d88ab6ccb1713a48 (block: Produce zeros when
protocols reading beyond end of file), we break qemu-iotests ./check
-qcow2 022. This happens because qcow2 temporarily sets ->growable = 1
for vmstate accesses (which are stored beyond the end of regular image
data).
We introduce the bs->zero_beyond_eof to allow qcow2_load_vmstate() to
disable ->zero_beyond_eof temporarily in addition to enable ->growable.
[Since the broken patch "block: Produce zeros when protocols reading
beyond end of file" has not been merged yet, I have applied this fix
*first* and will then apply the next patch to keep the tree bisectable.
-- Stefan]
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
[ Note: RHEL and upstream has reversed order of these two patches:
1) block: Produce zeros when protocols reading beyond end of file)
2) Introduce bs->zero_beyond_eof ]
Signed-off-by: Asias He <asias@redhat.com>
---
block.c | 4 +++-
block/qcow2.c | 3 +++
block_int.h | 3 +++
3 files changed, 9 insertions(+), 1 deletion(-)
Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
block.c | 4 +++-
block/qcow2.c | 3 +++
block_int.h | 3 +++
3 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 9ca164d..a99ca2b 100644
--- a/block.c
+++ b/block.c
@@ -563,6 +563,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename,
bs->open_flags = flags;
/* buffer_alignment defaulted to 512, drivers can change this value */
bs->buffer_alignment = 512;
+ bs->zero_beyond_eof = true;
open_flags = flags;
/*
@@ -1052,6 +1053,7 @@ void bdrv_close(BlockDriverState *bs)
bs->copy_on_read = 0;
bs->backing_file[0] = '\0';
bs->backing_format[0] = '\0';
+ bs->zero_beyond_eof = false;
if (bs->file != NULL) {
bdrv_close(bs->file);
@@ -2181,7 +2183,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
}
}
- if (!bs->growable) {
+ if (!(bs->zero_beyond_eof && bs->growable)) {
ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
} else {
/* Read zeros after EOF of growable BDSes */
diff --git a/block/qcow2.c b/block/qcow2.c
index dd01506..f209a5c 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1308,12 +1308,15 @@ static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
{
BDRVQcowState *s = bs->opaque;
int growable = bs->growable;
+ bool zero_beyond_eof = bs->zero_beyond_eof;
int ret;
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
bs->growable = 1;
+ bs->zero_beyond_eof = false;
ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size);
bs->growable = growable;
+ bs->zero_beyond_eof = zero_beyond_eof;
return ret;
}
diff --git a/block_int.h b/block_int.h
index 9fab23d..bea2a48 100644
--- a/block_int.h
+++ b/block_int.h
@@ -297,6 +297,9 @@ struct BlockDriverState {
/* Whether the disk can expand beyond total_sectors */
int growable;
+ /* Whether produces zeros when read beyond eof */
+ bool zero_beyond_eof;
+
/* the memory alignment required for the buffers handled by this driver */
int buffer_alignment;
--
1.7.11.7