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[Qemu-devel] [PATCHv2 1.8 7/9] qemu-img: round down request length to an
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCHv2 1.8 7/9] qemu-img: round down request length to an aligned sector |
Date: |
Tue, 26 Nov 2013 09:56:21 +0100 |
this patch shortens requests to end at an aligned sector so that
the next request starts aligned.
Signed-off-by: Peter Lieven <address@hidden>
---
qemu-img.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index b076d44..1421f0f 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1124,8 +1124,7 @@ out3:
static int img_convert(int argc, char **argv)
{
- int c, n, n1, bs_n, bs_i, compress, cluster_size,
- cluster_sectors, skip_create;
+ int c, n, n1, bs_n, bs_i, compress, cluster_sectors, skip_create;
int64_t ret = 0;
int progress = 0, flags;
const char *fmt, *out_fmt, *cache, *out_baseimg, *out_filename;
@@ -1397,19 +1396,21 @@ static int img_convert(int argc, char **argv)
}
}
+ cluster_sectors = 0;
+ ret = bdrv_get_info(out_bs, &bdi);
+ if (ret < 0 && compress) {
+ error_report("could not get block driver info");
+ goto out;
+ } else {
+ cluster_sectors = bdi.cluster_size / BDRV_SECTOR_SIZE;
+ }
+
if (compress) {
- ret = bdrv_get_info(out_bs, &bdi);
- if (ret < 0) {
- error_report("could not get block driver info");
- goto out;
- }
- cluster_size = bdi.cluster_size;
- if (cluster_size <= 0 || cluster_size > bufsectors * BDRV_SECTOR_SIZE)
{
+ if (cluster_sectors <= 0 || cluster_sectors > bufsectors) {
error_report("invalid cluster size");
ret = -1;
goto out;
}
- cluster_sectors = cluster_size >> 9;
sector_num = 0;
nb_sectors = total_sectors;
@@ -1547,6 +1548,15 @@ static int img_convert(int argc, char **argv)
n = nb_sectors;
}
+ /* round down request length to an aligned sector */
+ if (cluster_sectors > 0 && n >= cluster_sectors) {
+ int64_t next_aligned_sector = (sector_num + n);
+ next_aligned_sector -= next_aligned_sector % cluster_sectors;
+ if (sector_num + n > next_aligned_sector) {
+ n = next_aligned_sector - sector_num;
+ }
+ }
+
if (n > bs_offset + bs_sectors - sector_num) {
n = bs_offset + bs_sectors - sector_num;
}
--
1.7.9.5
- [Qemu-devel] [PATCHv2 1.8 5/9] block/iscsi: set bs->bl.opt_transfer_length, (continued)
- [Qemu-devel] [PATCHv2 1.8 7/9] qemu-img: round down request length to an aligned sector,
Peter Lieven <=