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[Qemu-devel] [PATCH 1.8 5/6] qemu-img: add option to align writes to clu
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCH 1.8 5/6] qemu-img: add option to align writes to cluster_sectors during convert |
Date: |
Mon, 25 Nov 2013 14:57:19 +0100 |
Signed-off-by: Peter Lieven <address@hidden>
---
qemu-img-cmds.hx | 4 ++--
qemu-img.c | 37 +++++++++++++++++++++++++------------
qemu-img.texi | 5 ++++-
3 files changed, 31 insertions(+), 15 deletions(-)
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index e0b8ab4..266cdf3 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -34,9 +34,9 @@ STEXI
ETEXI
DEF("convert", img_convert,
- "convert [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-O output_fmt] [-o
options] [-s snapshot_name] [-S sparse_size] [-m iobuf_size] filename
[filename2 [...]] output_filename")
+ "convert [-c] [-p] [-q] [-n] [-a] [-f fmt] [-t cache] [-O output_fmt] [-o
options] [-s snapshot_name] [-S sparse_size] [-m iobuf_size] filename
[filename2 [...]] output_filename")
STEXI
address@hidden convert [-c] [-p] [-q] [-n] [-f @var{fmt}] [-t @var{cache}] [-O
@var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S
@var{sparse_size}] [-m @var{iobuf_size}] @var{filename} address@hidden [...]]
@var{output_filename}
address@hidden convert [-c] [-p] [-q] [-n] [-a] [-f @var{fmt}] [-t @var{cache}]
[-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S
@var{sparse_size}] [-m @var{iobuf_size}] @var{filename} address@hidden [...]]
@var{output_filename}
ETEXI
DEF("info", img_info,
diff --git a/qemu-img.c b/qemu-img.c
index 0ce5d14..9fa8fd4 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -109,6 +109,7 @@ static void help(void)
" '--output' takes the format in which the output must be done
(human or json)\n"
" '-n' skips the target volume creation (useful if the volume is
created\n"
" prior to running qemu-img)\n"
+ " '-a' align write requests to cluster size if possible\n"
"\n"
"Parameters to check subcommand:\n"
" '-r' tries to repair any inconsistencies that are found during
the check.\n"
@@ -1125,8 +1126,7 @@ 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;
@@ -1144,7 +1144,7 @@ static int img_convert(int argc, char **argv)
char *options = NULL;
const char *snapshot_name = NULL;
int min_sparse = 8; /* Need at least 4k of zeros for sparse detection */
- bool quiet = false;
+ bool quiet = false, align = false;
Error *local_err = NULL;
fmt = NULL;
@@ -1154,7 +1154,7 @@ static int img_convert(int argc, char **argv)
compress = 0;
skip_create = 0;
for(;;) {
- c = getopt(argc, argv, "f:O:B:s:hce6o:pS:m:t:qn");
+ c = getopt(argc, argv, "f:O:B:s:hcae6o:pS:m:t:qn");
if (c == -1) {
break;
}
@@ -1175,6 +1175,9 @@ static int img_convert(int argc, char **argv)
case 'c':
compress = 1;
break;
+ case 'a':
+ align = true;
+ break;
case 'e':
error_report("option -e is deprecated, please use \'-o "
"encryption\' instead!");
@@ -1402,19 +1405,21 @@ 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;
@@ -1552,6 +1557,14 @@ static int img_convert(int argc, char **argv)
n = nb_sectors;
}
+ if (align && cluster_sectors > 0) {
+ int64_t next_aligned_sector = (sector_num + cluster_sectors);
+ 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;
}
diff --git a/qemu-img.texi b/qemu-img.texi
index 87f9d0f..9b1720f 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -179,11 +179,14 @@ Error on reading data
@end table
address@hidden convert [-c] [-p] [-n] [-f @var{fmt}] [-t @var{cache}] [-O
@var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S
@var{sparse_size}] [-m @var{iobuf_size}] @var{filename} address@hidden [...]]
@var{output_filename}
address@hidden convert [-c] [-p] [-n] [-a] [-f @var{fmt}] [-t @var{cache}] [-O
@var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S
@var{sparse_size}] [-m @var{iobuf_size}] @var{filename} address@hidden [...]]
@var{output_filename}
Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to
disk image @var{output_filename}
using format @var{output_fmt}. It can be optionally compressed (@code{-c}
option) or use any format specific options like encryption (@code{-o} option).
+If the @code{-a} option is specified write requests will be aligned
+to the cluster size of the output image if possible. This is the default
+for compressed images.
Only the formats @code{qcow} and @code{qcow2} support compression. The
compression is read-only. It means that if a compressed sector is
--
1.7.9.5
- Re: [Qemu-devel] [PATCH 1.8 3/6] qemu-img: add option to specify alternate iobuffer size, (continued)
[Qemu-devel] [PATCH 1.8 2/6] qemu-img: fix usage instruction for qemu-img convert, Peter Lieven, 2013/11/25
[Qemu-devel] [PATCH 1.8 1/6] qemu-img: add support for skipping zeroes in input during convert, Peter Lieven, 2013/11/25
[Qemu-devel] [PATCH 1.8 4/6] block/iscsi: set bdi->cluster_size, Peter Lieven, 2013/11/25
[Qemu-devel] [PATCH 1.8 6/6] qemu-img: add option to show progress in sectors, Peter Lieven, 2013/11/25
[Qemu-devel] [PATCH 1.8 5/6] qemu-img: add option to align writes to cluster_sectors during convert,
Peter Lieven <=
Re: [Qemu-devel] [PATCH 1.8 5/6] qemu-img: add option to align writes to cluster_sectors during convert, Peter Lieven, 2013/11/25
Re: [Qemu-devel] [PATCH 1.8 5/6] qemu-img: add option to align writes to cluster_sectors during convert, Paolo Bonzini, 2013/11/25