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[Qemu-devel] [PATCH v5 10/21] block: make bdrv_has_zero_init return fals
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH v5 10/21] block: make bdrv_has_zero_init return false for copy-on-write-images |
Date: |
Wed, 4 Sep 2013 19:00:27 +0200 |
This helps implementing is_allocated on top of get_block_status.
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
block.c | 5 +++++
qemu-img.c | 9 +--------
2 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/block.c b/block.c
index a3f7577..e18ff71 100644
--- a/block.c
+++ b/block.c
@@ -3011,6 +3011,11 @@ int bdrv_has_zero_init(BlockDriverState *bs)
{
assert(bs->drv);
+ /* If BS is a copy on write image, it is initialized to
+ the contents of the base image, which may not be zeroes. */
+ if (bs->backing_hd) {
+ return 0;
+ }
if (bs->drv->bdrv_has_zero_init) {
return bs->drv->bdrv_has_zero_init(bs);
}
diff --git a/qemu-img.c b/qemu-img.c
index 837f8bc..d50e0fc 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1514,14 +1514,7 @@ static int img_convert(int argc, char **argv)
should add a specific call to have the info to go faster */
buf1 = buf;
while (n > 0) {
- /* If the output image is being created as a copy on write
image,
- copy all sectors even the ones containing only NUL bytes,
- because they may differ from the sectors in the base image.
-
- If the output is to a host device, we also write out
- sectors that are entirely 0, since whatever data was
- already there is garbage, not 0s. */
- if (!has_zero_init || out_baseimg ||
+ if (!has_zero_init ||
is_allocated_sectors_min(buf1, n, &n1, min_sparse)) {
ret = bdrv_write(out_bs, sector_num, buf1, n1);
if (ret < 0) {
--
1.8.3.1
- [Qemu-devel] [PATCH v5 00/21] Add qemu-img subcommand to dump file metadata, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 01/21] cow: make reads go at a decent speed, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 02/21] cow: make writes go at a less indecent speed, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 03/21] cow: do not call bdrv_co_is_allocated, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 04/21] block: keep bs->total_sectors up to date even for growable block devices, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 06/21] block: do not use ->total_sectors in bdrv_co_is_allocated, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 05/21] block: make bdrv_co_is_allocated static, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 08/21] block: expect errors from bdrv_co_is_allocated, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 07/21] block: remove bdrv_is_allocated_above/bdrv_co_is_allocated_above distinction, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 10/21] block: make bdrv_has_zero_init return false for copy-on-write-images,
Paolo Bonzini <=
- [Qemu-devel] [PATCH v5 11/21] block: introduce bdrv_get_block_status API, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 12/21] block: define get_block_status return value, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 13/21] block: return get_block_status data and flags for formats, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 09/21] qemu-img: always probe the input image for allocated sectors, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 14/21] block: use bdrv_has_zero_init to return BDRV_BLOCK_ZERO, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 16/21] qemu-img: add a "map" subcommand, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 15/21] block: return BDRV_BLOCK_ZERO past end of backing file, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 17/21] docs, qapi: document qemu-img map, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 18/21] raw-posix: return get_block_status data and flags, Paolo Bonzini, 2013/09/04
- [Qemu-devel] [PATCH v5 19/21] raw-posix: report unwritten extents as zero, Paolo Bonzini, 2013/09/04