We are gradually moving away from sector-based interfaces, towards
byte-based. In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.
Changing the signature of the function to use int64_t *pnum ensures
that the compiler enforces that all callers are updated. For now,
the io.c layer still assert()s that all callers are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status. Therefore, for the most part this patch is just the
addition of scaling at the callers followed by inverse scaling at
bdrv_is_allocated(). But some code, particularly stream_run(),
gets a lot simpler because it no longer has to mess with sectors.
For ease of review, bdrv_is_allocated() was tackled separately.
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
v2: tweak function comments, favor bdrv_getlength() over ->total_sectors
---
include/block/block.h | 2 +-
block/commit.c | 20 ++++++++------------
block/io.c | 42 ++++++++++++++++++++----------------------
block/mirror.c | 5 ++++-
block/replication.c | 17 ++++++++++++-----
block/stream.c | 21 +++++++++------------
qemu-img.c | 10 +++++++---
7 files changed, 61 insertions(+), 56 deletions(-)
diff --git a/include/block/block.h b/include/block/block.h
index 47719ac..81e3325 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -437,7 +437,7 @@ int64_t bdrv_get_block_status_above(BlockDriverState *bs,
int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
int64_t *pnum);
int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
- int64_t sector_num, int nb_sectors, int *pnum);
+ int64_t offset, int64_t bytes, int64_t *pnum);
bool bdrv_is_read_only(BlockDriverState *bs);
int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
diff --git a/block/commit.c b/block/commit.c
index 4d6bb2a..989de7d 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -132,7 +132,7 @@ static void coroutine_fn commit_run(void *opaque)
int64_t offset;
uint64_t delay_ns = 0;
int ret = 0;
- int n = 0; /* sectors */
+ int64_t n = 0; /* bytes */
void *buf = NULL;
int bytes_written = 0;
int64_t base_len;
@@ -157,7 +157,7 @@ static void coroutine_fn commit_run(void *opaque)
buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
- for (offset = 0; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) {
+ for (offset = 0; offset < s->common.len; offset += n) {
bool copy;
/* Note that even when no rate limit is applied we need to yield
@@ -169,15 +169,12 @@ static void coroutine_fn commit_run(void *opaque)
}
/* Copy if allocated above the base */
ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
- offset / BDRV_SECTOR_SIZE,
- COMMIT_BUFFER_SIZE / BDRV_SECTOR_SIZE,
- &n);
+ offset, COMMIT_BUFFER_SIZE, &n);
copy = (ret == 1);
- trace_commit_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret);
+ trace_commit_one_iteration(s, offset, n, ret);
if (copy) {
- ret = commit_populate(s->top, s->base, offset,
- n * BDRV_SECTOR_SIZE, buf);
- bytes_written += n * BDRV_SECTOR_SIZE;
+ ret = commit_populate(s->top, s->base, offset, n, buf);
+ bytes_written += n;
}
if (ret < 0) {
BlockErrorAction action =
@@ -190,11 +187,10 @@ static void coroutine_fn commit_run(void *opaque)
}
}
/* Publish progress */
- s->common.offset += n * BDRV_SECTOR_SIZE;
+ s->common.offset += n;
if (copy && s->common.speed) {
- delay_ns = ratelimit_calculate_delay(&s->limit,
- n * BDRV_SECTOR_SIZE);
+ delay_ns = ratelimit_calculate_delay(&s->limit, n);
}
}
diff --git a/block/io.c b/block/io.c
index 20d3ebd..d4f1925 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1918,54 +1918,52 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState
*bs, int64_t offset,
/*
* Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
*
- * 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,
+ * Return true if the (prefix of the) given range is allocated in any image
+ * between BASE and TOP (inclusive). BASE can be NULL to check if the given
+ * offset is allocated in any image of the chain. Return false otherwise,
* or negative errno on failure.
*
- * '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.
+ * 'pnum' is set to the number of bytes (including and immediately
+ * following the specified offset) that are known to be in the same
+ * allocated/unallocated state. Note that a subsequent call starting
+ * at 'offset + *pnum' may return the same allocation status (in other
+ * words, the result is not necessarily the maximum possible range);
+ * but 'pnum' will only be 0 when end of file is reached.
*
*/
int bdrv_is_allocated_above(BlockDriverState *top,
BlockDriverState *base,
- int64_t sector_num,
- int nb_sectors, int *pnum)
+ int64_t offset, int64_t bytes, int64_t *pnum)
{
BlockDriverState *intermediate;
- int ret, n = nb_sectors;
+ int ret;
+ int64_t n = bytes;
intermediate = top;
while (intermediate && intermediate != base) {
int64_t pnum_inter;
int64_t size_inter;
- int psectors_inter;
- ret = bdrv_is_allocated(intermediate, sector_num * BDRV_SECTOR_SIZE,
- nb_sectors * BDRV_SECTOR_SIZE,
- &pnum_inter);
+ ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter);
if (ret < 0) {
return ret;
}
- assert(pnum_inter < INT_MAX * BDRV_SECTOR_SIZE);
- psectors_inter = pnum_inter >> BDRV_SECTOR_BITS;
if (ret) {
- *pnum = psectors_inter;
+ *pnum = pnum_inter;
return 1;
}
/*
- * [sector_num, nb_sectors] is unallocated on top but intermediate
- * might have [sector_num+x, nb_sectors-x] allocated.
+ * [offset, bytes] is unallocated on top but intermediate
+ * might have [offset+x, bytes-x] allocated.
*/
- size_inter = bdrv_nb_sectors(intermediate);
+ size_inter = bdrv_getlength(intermediate);
if (size_inter < 0) {
return size_inter;
}
- if (n > psectors_inter &&
- (intermediate == top || sector_num + psectors_inter < size_inter))
{
- n = psectors_inter;
+ if (n > pnum_inter &&
+ (intermediate == top || offset + pnum_inter < size_inter)) {
+ n = pnum_inter;
}
intermediate = backing_bs(intermediate);
diff --git a/block/mirror.c b/block/mirror.c
index 2a95ba5..452d546 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -609,6 +609,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
BlockDriverState *bs = s->source;
BlockDriverState *target_bs = blk_bs(s->target);
int ret, n;
+ int64_t count;
end = s->bdev_length / BDRV_SECTOR_SIZE;
@@ -658,11 +659,13 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob
*s)
return 0;
}
- ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n);
+ ret = bdrv_is_allocated_above(bs, base, sector_num * BDRV_SECTOR_SIZE,
+ nb_sectors * BDRV_SECTOR_SIZE, &count);
if (ret < 0) {
return ret;
}
+ n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
assert(n > 0);
if (ret == 1) {
bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n);
diff --git a/block/replication.c b/block/replication.c
index 137a7fc..52f4a8e 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -264,7 +264,8 @@ static coroutine_fn int
replication_co_writev(BlockDriverState *bs,
BdrvChild *top = bs->file;
BdrvChild *base = s->secondary_disk;
BdrvChild *target;
- int ret, n;
+ int ret;
+ int64_t n;
ret = replication_get_io_status(s);
if (ret < 0) {
@@ -283,14 +284,20 @@ static coroutine_fn int
replication_co_writev(BlockDriverState *bs,
*/
qemu_iovec_init(&hd_qiov, qiov->niov);
while (remaining_sectors > 0) {
- ret = bdrv_is_allocated_above(top->bs, base->bs, sector_num,
- remaining_sectors, &n);
+ int64_t count;
+
+ ret = bdrv_is_allocated_above(top->bs, base->bs,
+ sector_num * BDRV_SECTOR_SIZE,
+ remaining_sectors * BDRV_SECTOR_SIZE,
+ &count);
if (ret < 0) {
goto out1;
}
+ assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
+ n = count >> BDRV_SECTOR_BITS;
qemu_iovec_reset(&hd_qiov);
- qemu_iovec_concat(&hd_qiov, qiov, bytes_done, n * BDRV_SECTOR_SIZE);
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count);
target = ret ? top : base;
ret = bdrv_co_writev(target, sector_num, n, &hd_qiov);
@@ -300,7 +307,7 @@ static coroutine_fn int
replication_co_writev(BlockDriverState *bs,
remaining_sectors -= n;
sector_num += n;
- bytes_done += n * BDRV_SECTOR_SIZE;
+ bytes_done += count;
}
out1:
diff --git a/block/stream.c b/block/stream.c
index 85502eb..9033655 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -112,7 +112,7 @@ static void coroutine_fn stream_run(void *opaque)
uint64_t delay_ns = 0;
int error = 0;
int ret = 0;
- int n = 0; /* sectors */
+ int64_t n = 0; /* bytes */
void *buf;
if (!bs->backing) {
@@ -136,9 +136,8 @@ static void coroutine_fn stream_run(void *opaque)
bdrv_enable_copy_on_read(bs);
}
- for ( ; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) {
+ for ( ; offset < s->common.len; offset += n) {
bool copy;
- int64_t count = 0;
/* Note that even when no rate limit is applied we need to yield
* with no pending I/O here so that bdrv_drain_all() returns.
@@ -150,26 +149,25 @@ static void coroutine_fn stream_run(void *opaque)
copy = false;
- ret = bdrv_is_allocated(bs, offset, STREAM_BUFFER_SIZE, &count);
- n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
+ ret = bdrv_is_allocated(bs, offset, STREAM_BUFFER_SIZE, &n);
if (ret == 1) {
/* Allocated in the top, no need to copy. */
} else if (ret >= 0) {
/* Copy if allocated in the intermediate images. Limit to the
* known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). */
ret = bdrv_is_allocated_above(backing_bs(bs), base,
- offset / BDRV_SECTOR_SIZE, n, &n);
+ offset, n, &n);
/* Finish early if end of backing file has been reached */
if (ret == 0 && n == 0) {
- n = (s->common.len - offset) / BDRV_SECTOR_SIZE;
+ n = s->common.len - offset;
}
copy = (ret == 1);
}
- trace_stream_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret);
+ trace_stream_one_iteration(s, offset, n, ret);
if (copy) {
- ret = stream_populate(blk, offset, n * BDRV_SECTOR_SIZE, buf);
+ ret = stream_populate(blk, offset, n, buf);
}
if (ret < 0) {
BlockErrorAction action =
@@ -188,10 +186,9 @@ static void coroutine_fn stream_run(void *opaque)
ret = 0;
/* Publish progress */
- s->common.offset += n * BDRV_SECTOR_SIZE;
+ s->common.offset += n;
if (copy && s->common.speed) {
- delay_ns = ratelimit_calculate_delay(&s->limit,
- n * BDRV_SECTOR_SIZE);
+ delay_ns = ratelimit_calculate_delay(&s->limit, n);
}
}
diff --git a/qemu-img.c b/qemu-img.c
index 3b17709..08864f3 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1476,12 +1476,16 @@ static int img_compare(int argc, char **argv)
}
for (;;) {
+ int64_t count;
+
nb_sectors = sectors_to_process(total_sectors_over, sector_num);
if (nb_sectors <= 0) {
break;
}
- ret = bdrv_is_allocated_above(blk_bs(blk_over), NULL, sector_num,
- nb_sectors, &pnum);
+ ret = bdrv_is_allocated_above(blk_bs(blk_over), NULL,
+ sector_num * BDRV_SECTOR_SIZE,
+ nb_sectors * BDRV_SECTOR_SIZE,
+ &count);
if (ret < 0) {
ret = 3;
error_report("Sector allocation test failed for %s",
@@ -1489,7 +1493,7 @@ static int img_compare(int argc, char **argv)
goto out;
}
- nb_sectors = pnum;
+ nb_sectors = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
if (ret) {
ret = check_empty_sectors(blk_over, sector_num, nb_sectors,
filename_over, buf1, quiet);
--
2.9.3
