* [Qemu-devel] [RFC][PATCH] qemu-img: add support for skipping zeroes in input during convert
@ 2013-11-22 14:48 Peter Lieven
2013-12-02 14:13 ` Stefan Hajnoczi
0 siblings, 1 reply; 3+ messages in thread
From: Peter Lieven @ 2013-11-22 14:48 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, pbonzini, Peter Lieven, stefanha
Signed-off-by: Peter Lieven <pl@kamp.de>
---
qemu-img.c | 52 ++++++++++++++++++++++++++++++----------------------
1 file changed, 30 insertions(+), 22 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index b6b5644..808f8f8 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1121,8 +1121,9 @@ out3:
static int img_convert(int argc, char **argv)
{
- int c, ret = 0, n, n1, bs_n, bs_i, compress, cluster_size,
+ int c, n, n1, bs_n, bs_i, compress, cluster_size,
cluster_sectors, skip_create;
+ int64_t ret = 0;
int progress = 0, flags;
const char *fmt, *out_fmt, *cache, *out_baseimg, *out_filename;
BlockDriver *drv, *proto_drv;
@@ -1479,11 +1480,6 @@ static int img_convert(int argc, char **argv)
if (nb_sectors <= 0) {
break;
}
- if (nb_sectors >= (IO_BUF_SIZE / 512)) {
- n = (IO_BUF_SIZE / 512);
- } else {
- n = nb_sectors;
- }
while (sector_num - bs_offset >= bs_sectors) {
bs_i ++;
@@ -1495,34 +1491,46 @@ static int img_convert(int argc, char **argv)
sector_num, bs_i, bs_offset, bs_sectors); */
}
- if (n > bs_offset + bs_sectors - sector_num) {
- n = bs_offset + bs_sectors - sector_num;
- }
-
- /* If the output image is being created as a copy on write image,
- assume that sectors which are unallocated in the input image
- are present in both the output's and input's base images (no
- need to copy them). */
- if (out_baseimg) {
- ret = bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
- n, &n1);
+ if (out_baseimg || has_zero_init) {
+ n = nb_sectors > INT_MAX ? INT_MAX : nb_sectors;
+ ret = bdrv_get_block_status(bs[bs_i], sector_num - bs_offset,
+ n, &n1);
if (ret < 0) {
- error_report("error while reading metadata for sector "
- "%" PRId64 ": %s",
+ error_report("error while reading block status of sector %" PRId64 ": %s",
sector_num - bs_offset, strerror(-ret));
goto out;
}
- if (!ret) {
+ /* If the output image is zero initialized, we are not working
+ * on a shared base and the input is zero we can skip the next
+ * n1 bytes */
+ if (!out_baseimg && has_zero_init && ret & BDRV_BLOCK_ZERO) {
+ sector_num += n1;
+ continue;
+ }
+ /* If the output image is being created as a copy on write image,
+ assume that sectors which are unallocated in the input image
+ are present in both the output's and input's base images (no
+ need to copy them). */
+ if (out_baseimg && !(ret & BDRV_BLOCK_DATA)) {
sector_num += n1;
continue;
}
/* The next 'n1' sectors are allocated in the input image. Copy
only those as they may be followed by unallocated sectors. */
- n = n1;
+ nb_sectors = n1;
+ }
+
+ if (nb_sectors >= (IO_BUF_SIZE / 512)) {
+ n = (IO_BUF_SIZE / 512);
} else {
- n1 = n;
+ n = nb_sectors;
+ }
+
+ if (n > bs_offset + bs_sectors - sector_num) {
+ n = bs_offset + bs_sectors - sector_num;
}
+ n1 = n;
ret = bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n);
if (ret < 0) {
error_report("error while reading sector %" PRId64 ": %s",
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [RFC][PATCH] qemu-img: add support for skipping zeroes in input during convert
2013-11-22 14:48 [Qemu-devel] [RFC][PATCH] qemu-img: add support for skipping zeroes in input during convert Peter Lieven
@ 2013-12-02 14:13 ` Stefan Hajnoczi
2013-12-02 14:15 ` Peter Lieven
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Hajnoczi @ 2013-12-02 14:13 UTC (permalink / raw)
To: Peter Lieven; +Cc: kwolf, pbonzini, qemu-devel
On Fri, Nov 22, 2013 at 03:48:30PM +0100, Peter Lieven wrote:
> - /* If the output image is being created as a copy on write image,
> - assume that sectors which are unallocated in the input image
> - are present in both the output's and input's base images (no
> - need to copy them). */
> - if (out_baseimg) {
> - ret = bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
> - n, &n1);
int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum);
if (ret < 0) {
return ret;
}
return
(ret & BDRV_BLOCK_DATA) ||
((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs));
}
bdrv_has_zero_init() returns false when bs->backing_hd != NULL.
> + if (out_baseimg || has_zero_init) {
> + n = nb_sectors > INT_MAX ? INT_MAX : nb_sectors;
> + ret = bdrv_get_block_status(bs[bs_i], sector_num - bs_offset,
> + n, &n1);
> if (ret < 0) {
> - error_report("error while reading metadata for sector "
> - "%" PRId64 ": %s",
> + error_report("error while reading block status of sector %" PRId64 ": %s",
> sector_num - bs_offset, strerror(-ret));
> goto out;
> }
> - if (!ret) {
> + /* If the output image is zero initialized, we are not working
> + * on a shared base and the input is zero we can skip the next
> + * n1 bytes */
> + if (!out_baseimg && has_zero_init && ret & BDRV_BLOCK_ZERO) {
> + sector_num += n1;
> + continue;
> + }
> + /* If the output image is being created as a copy on write image,
> + assume that sectors which are unallocated in the input image
> + are present in both the output's and input's base images (no
> + need to copy them). */
> + if (out_baseimg && !(ret & BDRV_BLOCK_DATA)) {
> sector_num += n1;
> continue;
> }
How are these two if statements different from bdrv_is_allocated()?
Stefan
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [RFC][PATCH] qemu-img: add support for skipping zeroes in input during convert
2013-12-02 14:13 ` Stefan Hajnoczi
@ 2013-12-02 14:15 ` Peter Lieven
0 siblings, 0 replies; 3+ messages in thread
From: Peter Lieven @ 2013-12-02 14:15 UTC (permalink / raw)
To: Stefan Hajnoczi; +Cc: kwolf, pbonzini, qemu-devel
Hi Stefan,
please have a look at
[PATCHv2 1.8 0/9] qemu-img convert optimizations
This one here is obsolete.
Peter
Am 02.12.2013 um 15:13 schrieb Stefan Hajnoczi <stefanha@redhat.com>:
> On Fri, Nov 22, 2013 at 03:48:30PM +0100, Peter Lieven wrote:
>> - /* If the output image is being created as a copy on write image,
>> - assume that sectors which are unallocated in the input image
>> - are present in both the output's and input's base images (no
>> - need to copy them). */
>> - if (out_baseimg) {
>> - ret = bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
>> - n, &n1);
>
> int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
> int nb_sectors, int *pnum)
> {
> int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum);
> if (ret < 0) {
> return ret;
> }
> return
> (ret & BDRV_BLOCK_DATA) ||
> ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs));
> }
>
> bdrv_has_zero_init() returns false when bs->backing_hd != NULL.
>
>> + if (out_baseimg || has_zero_init) {
>> + n = nb_sectors > INT_MAX ? INT_MAX : nb_sectors;
>> + ret = bdrv_get_block_status(bs[bs_i], sector_num - bs_offset,
>> + n, &n1);
>> if (ret < 0) {
>> - error_report("error while reading metadata for sector "
>> - "%" PRId64 ": %s",
>> + error_report("error while reading block status of sector %" PRId64 ": %s",
>> sector_num - bs_offset, strerror(-ret));
>> goto out;
>> }
>> - if (!ret) {
>> + /* If the output image is zero initialized, we are not working
>> + * on a shared base and the input is zero we can skip the next
>> + * n1 bytes */
>> + if (!out_baseimg && has_zero_init && ret & BDRV_BLOCK_ZERO) {
>> + sector_num += n1;
>> + continue;
>> + }
>> + /* If the output image is being created as a copy on write image,
>> + assume that sectors which are unallocated in the input image
>> + are present in both the output's and input's base images (no
>> + need to copy them). */
>> + if (out_baseimg && !(ret & BDRV_BLOCK_DATA)) {
>> sector_num += n1;
>> continue;
>> }
>
> How are these two if statements different from bdrv_is_allocated()?
>
> Stefan
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-12-02 14:15 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-11-22 14:48 [Qemu-devel] [RFC][PATCH] qemu-img: add support for skipping zeroes in input during convert Peter Lieven
2013-12-02 14:13 ` Stefan Hajnoczi
2013-12-02 14:15 ` Peter Lieven
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).