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[Qemu-devel] [PULL 43/48] qemu-img: round down request length to an alig
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 43/48] qemu-img: round down request length to an aligned sector |
Date: |
Fri, 6 Dec 2013 17:36:42 +0100 |
From: Peter Lieven <address@hidden>
this patch shortens requests to end at an aligned sector so that
the next request starts aligned.
[Squashed Peter's fix for bdrv_get_info() failure discussed on the
mailing list.
--Stefan]
Reviewed-by: Paolo Bonzini <address@hidden>
Signed-off-by: Peter Lieven <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
qemu-img.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index 0725f22..76f05f2 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1129,8 +1129,7 @@ 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;
@@ -1424,19 +1423,23 @@ static int img_convert(int argc, char **argv)
}
}
- if (compress) {
- ret = bdrv_get_info(out_bs, &bdi);
- if (ret < 0) {
+ cluster_sectors = 0;
+ ret = bdrv_get_info(out_bs, &bdi);
+ if (ret < 0) {
+ if (compress) {
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)
{
+ } else {
+ cluster_sectors = bdi.cluster_size / BDRV_SECTOR_SIZE;
+ }
+
+ if (compress) {
+ 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;
@@ -1569,6 +1572,19 @@ static int img_convert(int argc, char **argv)
}
n = MIN(nb_sectors, bufsectors);
+
+ /* round down request length to an aligned sector, but
+ * do not bother doing this on short requests. They happen
+ * when we found an all-zero area, and the next sector to
+ * write will not be sector_num + n. */
+ 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;
+ }
+ }
+
n = MIN(n, bs_sectors - (sector_num - bs_offset));
n1 = n;
--
1.8.4.2
- [Qemu-devel] [PULL 33/48] qemu-iotests: add 058 internal snapshot export with qemu-nbd case, (continued)
- [Qemu-devel] [PULL 33/48] qemu-iotests: add 058 internal snapshot export with qemu-nbd case, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 34/48] qemu-img: add -l for snapshot in convert, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 35/48] qemu-iotests: add test for snapshot in qemu-img convert, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 36/48] qemu-nbd: add doc for option -f, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 37/48] qemu-img: add support for skipping zeroes in input during convert, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 38/48] qemu-img: fix usage instruction for qemu-img convert, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 39/48] block/iscsi: set bdi->cluster_size, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 40/48] block: add opt_transfer_length to BlockLimits, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 41/48] block/iscsi: set bs->bl.opt_transfer_length, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 42/48] qemu-img: dynamically adjust iobuffer size during convert, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 43/48] qemu-img: round down request length to an aligned sector,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 44/48] qemu-img: decrease progress update interval on convert, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 46/48] block: clean up bdrv_drain_all() throttling comments, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 47/48] aio: make aio_poll(ctx, true) block with no fds, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 48/48] qemu-iotests: filter QEMU monitor \r\n, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 45/48] qcow2: use start_of_cluster() and offset_into_cluster() everywhere, Stefan Hajnoczi, 2013/12/06
- [Qemu-devel] [PULL 31/48] snapshot: distinguish id and name in load_tmp, Stefan Hajnoczi, 2013/12/06