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[Qemu-block] [PATCH] qemu-img: improve convert_iteration_sectors()
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[Qemu-block] [PATCH] qemu-img: improve convert_iteration_sectors() |
Date: |
Fri, 7 Apr 2017 14:34:04 +0300 |
Do not do extra call to _get_block_status()
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
Also, I'm not sure about last line:
s->status = s->target_has_backing ? BLK_BACKING_FILE : BLK_DATA;
(which is equal to old code)
may be, it should be
s->status = s->target_has_backing ? BLK_BACKING_FILE : BLK_ZERO;
as it is the case, when range is not allocated at all. Should we copy it in
this case?
qemu-img.c | 32 ++++++++++----------------------
1 file changed, 10 insertions(+), 22 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index b220cf71d7..490f6e97f6 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1554,9 +1554,15 @@ static int convert_iteration_sectors(ImgConvertState *s,
int64_t sector_num)
if (s->sector_next_status <= sector_num) {
BlockDriverState *file;
- ret = bdrv_get_block_status(blk_bs(s->src[src_cur]),
- sector_num - src_cur_offset,
- n, &n, &file);
+ if (s->target_has_backing) {
+ ret = bdrv_get_block_status(blk_bs(s->src[src_cur]),
+ sector_num - src_cur_offset,
+ n, &n, &file);
+ } else {
+ ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,
+ sector_num - src_cur_offset,
+ n, &n, &file);
+ }
if (ret < 0) {
return ret;
}
@@ -1565,26 +1571,8 @@ static int convert_iteration_sectors(ImgConvertState *s,
int64_t sector_num)
s->status = BLK_ZERO;
} else if (ret & BDRV_BLOCK_DATA) {
s->status = BLK_DATA;
- } else if (!s->target_has_backing) {
- /* Without a target backing file we must copy over the contents of
- * the backing file as well. */
- /* Check block status of the backing file chain to avoid
- * needlessly reading zeroes and limiting the iteration to the
- * buffer size */
- ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,
- sector_num - src_cur_offset,
- n, &n, &file);
- if (ret < 0) {
- return ret;
- }
-
- if (ret & BDRV_BLOCK_ZERO) {
- s->status = BLK_ZERO;
- } else {
- s->status = BLK_DATA;
- }
} else {
- s->status = BLK_BACKING_FILE;
+ s->status = s->target_has_backing ? BLK_BACKING_FILE : BLK_DATA;
}
s->sector_next_status = sector_num + n;
--
2.11.1
- [Qemu-block] [PATCH] qemu-img: improve convert_iteration_sectors(),
Vladimir Sementsov-Ogievskiy <=