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authorEric Blake <eblake@redhat.com>2017-07-07 07:44:59 -0500
committerKevin Wolf <kwolf@redhat.com>2017-07-10 13:18:07 +0200
commit51b0a488882328f8f02519bb47ca7e0e7fbe12ff (patch)
tree36257cf2221ea7e4e54ab7deae446d02c46f326c
parentc00716beb30ba996bd6fdfd5f41bb07e4414144f (diff)
block: Make bdrv_is_allocated_above() byte-based
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. Leave comments where we can further simplify by switching to byte-based iterations, once later patches eliminate the need for sector-aligned operations. For ease of review, bdrv_is_allocated() was tackled separately. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/commit.c20
-rw-r--r--block/io.c38
-rw-r--r--block/mirror.c8
-rw-r--r--block/replication.c17
-rw-r--r--block/stream.c23
-rw-r--r--include/block/block.h2
-rw-r--r--qemu-img.c13
7 files changed, 65 insertions, 56 deletions
diff --git a/block/commit.c b/block/commit.c
index 241aa95b3f..774a8a599c 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -146,7 +146,7 @@ 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;
@@ -171,7 +171,7 @@ 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
@@ -183,15 +183,12 @@ 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 =
@@ -204,11 +201,10 @@ 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 aad7fd30a4..23170a57ee 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1926,50 +1926,48 @@ 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 (a 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;
}
- 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 b33f4bb1d6..eaf0fe7858 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -621,6 +621,7 @@ 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;
@@ -670,11 +671,16 @@ 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;
}
+ /* TODO: Relax this once bdrv_is_allocated_above and dirty
+ * bitmaps no longer require sector alignment. */
+ assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
+ n = count >> BDRV_SECTOR_BITS;
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 8f3aba7a20..bf4462c8e7 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 df9679c0fc..e6f72346e5 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -111,7 +111,7 @@ 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) {
@@ -135,9 +135,8 @@ 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.
@@ -149,28 +148,25 @@ static void coroutine_fn stream_run(void *opaque)
copy = false;
- ret = bdrv_is_allocated(bs, offset, STREAM_BUFFER_SIZE, &count);
- /* TODO relax this once bdrv_is_allocated does not enforce sectors */
- assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
- n = count >> BDRV_SECTOR_BITS;
+ 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 =
@@ -189,10 +185,9 @@ 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/include/block/block.h b/include/block/block.h
index 8d16cc1d98..4a2725267d 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -430,7 +430,7 @@ 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);
bool bdrv_is_writable(BlockDriverState *bs);
diff --git a/qemu-img.c b/qemu-img.c
index 86e24335fc..f7ffb79db6 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1508,12 +1508,16 @@ 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",
@@ -1521,7 +1525,10 @@ static int img_compare(int argc, char **argv)
goto out;
}
- nb_sectors = pnum;
+ /* TODO relax this once bdrv_is_allocated_above does not enforce
+ * sector alignment */
+ assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
+ nb_sectors = count >> BDRV_SECTOR_BITS;
if (ret) {
ret = check_empty_sectors(blk_over, sector_num, nb_sectors,
filename_over, buf1, quiet);