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[Qemu-devel] [PATCH 04/12] stream: tweak usage of bdrv_co_is_allocated
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 04/12] stream: tweak usage of bdrv_co_is_allocated |
Date: |
Mon, 4 Jun 2012 13:13:21 +0200 |
From: Paolo Bonzini <address@hidden>
is_allocated_base has complex semantics that are not really usable
outside streaming. Split the check in two parts, where the allocated
state for the top bs is moved to the caller. The resulting function
is more generally useful.
Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block/stream.c | 51 +++++++++++++++++++++++++--------------------------
1 files changed, 25 insertions(+), 26 deletions(-)
diff --git a/block/stream.c b/block/stream.c
index 8e58322..4490a25 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -101,45 +101,33 @@ static void close_unused_images(BlockDriverState *top,
BlockDriverState *base,
/*
* Given an image chain: [BASE] -> [INTER1] -> [INTER2] -> [TOP]
*
- * Return true if the given sector is allocated in top.
- * Return false if the given sector is allocated in intermediate images.
- * Return true otherwise.
+ * Return true if the given sector is allocated in any image between
+ * BASE and TOP (inclusive). BASE can be NULL to check if the given
+ * sector is allocated in any image of the chain. Return false otherwise.
*
* 'pnum' is set to the number of sectors (including and immediately following
* the specified sector) that are known to be in the same
* allocated/unallocated state.
*
*/
-static int coroutine_fn is_allocated_base(BlockDriverState *top,
- BlockDriverState *base,
- int64_t sector_num,
- int nb_sectors, int *pnum)
+static int coroutine_fn is_allocated_above(BlockDriverState *top,
+ BlockDriverState *base,
+ int64_t sector_num,
+ int nb_sectors, int *pnum)
{
BlockDriverState *intermediate;
- int ret, n;
-
- ret = bdrv_co_is_allocated(top, sector_num, nb_sectors, &n);
- if (ret) {
- *pnum = n;
- return ret;
- }
-
- /*
- * Is the unallocated chunk [sector_num, n] also
- * unallocated between base and top?
- */
- intermediate = top->backing_hd;
+ int ret, n = nb_sectors;
+ intermediate = top;
while (intermediate != base) {
int pnum_inter;
-
ret = bdrv_co_is_allocated(intermediate, sector_num, nb_sectors,
&pnum_inter);
if (ret < 0) {
return ret;
} else if (ret) {
*pnum = pnum_inter;
- return 0;
+ return 1;
}
/*
@@ -156,7 +144,7 @@ static int coroutine_fn is_allocated_base(BlockDriverState
*top,
}
*pnum = n;
- return 1;
+ return 0;
}
static void coroutine_fn stream_run(void *opaque)
@@ -189,6 +177,7 @@ static void coroutine_fn stream_run(void *opaque)
for (sector_num = 0; sector_num < end; sector_num += n) {
uint64_t delay_ns = 0;
+ bool copy;
wait:
/* Note that even when no rate limit is applied we need to yield
@@ -199,10 +188,20 @@ wait:
break;
}
- ret = is_allocated_base(bs, base, sector_num,
- STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n);
+ ret = bdrv_co_is_allocated(bs, sector_num,
+ STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n);
+ if (ret == 1) {
+ /* Allocated in the top, no need to copy. */
+ copy = false;
+ } else {
+ /* Copy if allocated in the intermediate images. Limit to the
+ * known-unallocated area [sector_num, sector_num+n). */
+ ret = is_allocated_above(bs->backing_hd, base, sector_num, n, &n);
+ copy = (ret == 1);
+ }
+
trace_stream_one_iteration(s, sector_num, n, ret);
- if (ret == 0) {
+ if (ret >= 0 && copy) {
if (s->common.speed) {
delay_ns = ratelimit_calculate_delay(&s->limit, n);
if (delay_ns > 0) {
--
1.7.6.5
- Re: [Qemu-devel] [PATCH 02/12] qcow2: fix the byte endian convertion, (continued)
- [Qemu-devel] [PATCH 06/12] stream: move rate limiting to a separate header file, Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 05/12] stream: move is_allocated_above to block.c, Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 10/12] qcow2: Support for fixing refcount inconsistencies, Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 08/12] qemu-img check -r for repairing images, Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 09/12] qemu-img check: Print fixed clusters and recheck, Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 07/12] Un-inline fdctrl_init_isa(), Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 03/12] block: implement is_allocated for raw, Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 11/12] rbd: hook up cache options, Kevin Wolf, 2012/06/04
- [Qemu-devel] [PATCH 04/12] stream: tweak usage of bdrv_co_is_allocated,
Kevin Wolf <=
- [Qemu-devel] [PATCH 12/12] sheepdog: add coroutine_fn markers to coroutine functions, Kevin Wolf, 2012/06/04
- Re: [Qemu-devel] [PULL 00/12] Block patches, Anthony Liguori, 2012/06/06