diff --git a/block.c b/block.c
index a307c151a8dbba4a145393afa56f18d40088c552..0af890f64759fc8bfd29460d00b4e17181a040c0 100644
--- a/block.c
+++ b/block.c
@@ -6480,6 +6480,13 @@ int coroutine_fn bdrv_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
}
memset(bdi, 0, sizeof(*bdi));
ret = drv->bdrv_co_get_info(bs, bdi);
+ if (bdi->subcluster_size == 0) {
+ /*
+ * If the driver left this unset, subclusters are not supported.
+ * Then it is safe to treat each cluster as having only one subcluster.
+ */
+ bdi->subcluster_size = bdi->cluster_size;
+ }
if (ret < 0) {
return ret;
}
diff --git a/block/io.c b/block/io.c
index 055fcf7438e6edddd902da4660219886cfde236d..76e7df18d81bf336377fcb3d80aba272869e2e31 100644
--- a/block/io.c
+++ b/block/io.c
@@ -728,21 +728,21 @@ BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs)
}
/**
- * Round a region to cluster boundaries
+ * Round a region to subcluster (if supported) or cluster boundaries
*/
void coroutine_fn GRAPH_RDLOCK
-bdrv_round_to_clusters(BlockDriverState *bs, int64_t offset, int64_t bytes,
- int64_t *cluster_offset, int64_t *cluster_bytes)
+bdrv_round_to_subclusters(BlockDriverState *bs, int64_t offset, int64_t bytes,
+ int64_t *align_offset, int64_t *align_bytes)
{
BlockDriverInfo bdi;
IO_CODE();
- if (bdrv_co_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
- *cluster_offset = offset;
- *cluster_bytes = bytes;
+ if (bdrv_co_get_info(bs, &bdi) < 0 || bdi.subcluster_size == 0) {
+ *align_offset = offset;
+ *align_bytes = bytes;
} else {
- int64_t c = bdi.cluster_size;
- *cluster_offset = QEMU_ALIGN_DOWN(offset, c);
- *cluster_bytes = QEMU_ALIGN_UP(offset - *cluster_offset + bytes, c);
+ int64_t c = bdi.subcluster_size;
+ *align_offset = QEMU_ALIGN_DOWN(offset, c);
+ *align_bytes = QEMU_ALIGN_UP(offset - *align_offset + bytes, c);
}
}
@@ -1168,8 +1168,8 @@ bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes,
void *bounce_buffer = NULL;
BlockDriver *drv = bs->drv;
- int64_t cluster_offset;
- int64_t cluster_bytes;
+ int64_t align_offset;
+ int64_t align_bytes;
int64_t skip_bytes;
int ret;
int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer,
@@ -1203,28 +1203,28 @@ bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes,
* BDRV_REQUEST_MAX_BYTES (even when the original read did not), which
* is one reason we loop rather than doing it all at once.
*/
- bdrv_round_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes);
- skip_bytes = offset - cluster_offset;
+ bdrv_round_to_subclusters(bs, offset, bytes, &align_offset, &align_bytes);
+ skip_bytes = offset - align_offset;
trace_bdrv_co_do_copy_on_readv(bs, offset, bytes,
- cluster_offset, cluster_bytes);
+ align_offset, align_bytes);
- while (cluster_bytes) {
+ while (align_bytes) {
int64_t pnum;
if (skip_write) {
ret = 1; /* "already allocated", so nothing will be copied */
- pnum = MIN(cluster_bytes, max_transfer);
+ pnum = MIN(align_bytes, max_transfer);
} else {
- ret = bdrv_is_allocated(bs, cluster_offset,
- MIN(cluster_bytes, max_transfer), &pnum);
+ ret = bdrv_is_allocated(bs, align_offset,
+ MIN(align_bytes, max_transfer), &pnum);
if (ret < 0) {
/*
* Safe to treat errors in querying allocation as if
* unallocated; we'll probably fail again soon on the
* read, but at least that will set a decent errno.
*/
- pnum = MIN(cluster_bytes, max_transfer);
+ pnum = MIN(align_bytes, max_transfer);
}
/* Stop at EOF if the image ends in the middle of the cluster */
@@ -1242,7 +1242,7 @@ bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes,
/* Must copy-on-read; use the bounce buffer */
pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
if (!bounce_buffer) {
- int64_t max_we_need = MAX(pnum, cluster_bytes - pnum);
+ int64_t max_we_need = MAX(pnum, align_bytes - pnum);
int64_t max_allowed = MIN(max_transfer, MAX_BOUNCE_BUFFER);
int64_t bounce_buffer_len = MIN(max_we_need, max_allowed);
@@ -1254,7 +1254,7 @@ bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes,
}
qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
- ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
+ ret = bdrv_driver_preadv(bs, align_offset, pnum,
&local_qiov, 0, 0);
if (ret < 0) {
goto err;
@@ -1266,13 +1266,13 @@ bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes,
/* FIXME: Should we (perhaps conditionally) be setting
* BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy
* that still correctly reads as zero? */
- ret = bdrv_co_do_pwrite_zeroes(bs, cluster_offset, pnum,
+ ret = bdrv_co_do_pwrite_zeroes(bs, align_offset, pnum,
BDRV_REQ_WRITE_UNCHANGED);
} else {
/* This does not change the data on the disk, it is not
* necessary to flush even in cache=writethrough mode.
*/
- ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
+ ret = bdrv_driver_pwritev(bs, align_offset, pnum,
&local_qiov, 0,
BDRV_REQ_WRITE_UNCHANGED);
}
@@ -1301,8 +1301,8 @@ bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes,
}
}
- cluster_offset += pnum;
- cluster_bytes -= pnum;
+ align_offset += pnum;
+ align_bytes -= pnum;
progress += pnum - skip_bytes;
skip_bytes = 0;
}
diff --git a/block/mirror.c b/block/mirror.c
index d3cacd170860ee86c8a5f870543e19e92b3a490f..e213a892dbfdedc9b1332063f2509599d6fb091d 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -283,8 +283,8 @@ static int coroutine_fn mirror_cow_align(MirrorBlockJob *s, int64_t *offset,
need_cow |= !test_bit((*offset + *bytes - 1) / s->granularity,
s->cow_bitmap);
if (need_cow) {
- bdrv_round_to_clusters(blk_bs(s->target), *offset, *bytes,
- &align_offset, &align_bytes);
+ bdrv_round_to_subclusters(blk_bs(s->target), *offset, *bytes,
+ &align_offset, &align_bytes);
}
if (align_bytes > max_bytes) {
@@ -576,8 +576,8 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
int64_t target_offset;
int64_t target_bytes;
WITH_GRAPH_RDLOCK_GUARD() {
- bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes,
- &target_offset, &target_bytes);
+ bdrv_round_to_subclusters(blk_bs(s->target), offset, io_bytes,
+ &target_offset, &target_bytes);
}
if (target_offset == offset &&
target_bytes == io_bytes) {
diff --git a/block/qcow2.c b/block/qcow2.c
index c51388e99d8de9a38bf6661c66c2f7ef7f0558c8..b48cd9ce6365da4eb63eca4d5681c9b1ab2ca450 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5197,6 +5197,7 @@ qcow2_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVQcow2State *s = bs->opaque;
bdi->cluster_size = s->cluster_size;
+ bdi->subcluster_size = s->subcluster_size;
bdi->vm_state_offset = qcow2_vm_state_offset(s);
bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY;
return 0;
diff --git a/include/block/block-common.h b/include/block/block-common.h
index e15395f2cbb7545e418d2910826af35eb1307815..df5ffc8d09e84be1c7ee97c3975a005e0c878188 100644
--- a/include/block/block-common.h
+++ b/include/block/block-common.h
@@ -132,6 +132,11 @@ typedef struct BlockZoneWps {
typedef struct BlockDriverInfo {
/* in bytes, 0 if irrelevant */
int cluster_size;
+ /*
+ * A fraction of cluster_size, if supported (currently QCOW2 only); if
+ * disabled or unsupported, set equal to cluster_size.
+ */
+ int subcluster_size;
/* offset at which the VM state can be saved (0 if not possible) */
int64_t vm_state_offset;
bool is_dirty;
diff --git a/include/block/block-io.h b/include/block/block-io.h
index 4415506e409620a08c86d75066245f76a0b947ec..6db48f2d3594678a60fcfad2e0dd7d0302e9eeaa 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -189,10 +189,10 @@ bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
Error **errp);
BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
-void bdrv_round_to_clusters(BlockDriverState *bs,
- int64_t offset, int64_t bytes,
- int64_t *cluster_offset,
- int64_t *cluster_bytes);
+void bdrv_round_to_subclusters(BlockDriverState *bs,
+ int64_t offset, int64_t bytes,
+ int64_t *cluster_offset,
+ int64_t *cluster_bytes);
void bdrv_get_backing_filename(BlockDriverState *bs,
char *filename, int filename_size);
diff --git a/migration/block.c b/migration/block.c
index b9580a6c7e7041bf722de3eb1ae2a1261486242b..86c2256a2bfb3370aa93f901a4fc8a661a4b2edd 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -368,7 +368,9 @@ static void unset_dirty_tracking(void)
BlkMigDevState *bmds;
QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
- bdrv_release_dirty_bitmap(bmds->dirty_bitmap);
+ if (bmds->dirty_bitmap) {
+ bdrv_release_dirty_bitmap(bmds->dirty_bitmap);
+ }
}
}
@@ -676,13 +678,18 @@ static int64_t get_remaining_dirty(void)
static void block_migration_cleanup_bmds(void)
{
BlkMigDevState *bmds;
+ BlockDriverState *bs;
AioContext *ctx;
unset_dirty_tracking();
while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
- bdrv_op_unblock_all(blk_bs(bmds->blk), bmds->blocker);
+
+ bs = blk_bs(bmds->blk);
+ if (bs) {
+ bdrv_op_unblock_all(bs, bmds->blocker);
+ }
error_free(bmds->blocker);
/* Save ctx, because bmds->blk can disappear during blk_unref. */
diff --git a/tests/qemu-iotests/197 b/tests/qemu-iotests/197
index a2547bc280ca4cc8a08e84464a257f41fc2ef5c1..f07a9da136a9811e565527fab364e04c28004574 100755
--- a/tests/qemu-iotests/197
+++ b/tests/qemu-iotests/197
@@ -122,6 +122,35 @@ $QEMU_IO -f qcow2 -C -c 'read 0 1024' "$TEST_WRAP" | _filter_qemu_io
$QEMU_IO -f qcow2 -c map "$TEST_WRAP"
_check_test_img
+echo
+echo '=== Copy-on-read with subclusters ==='
+echo
+
+# Create base and top images 64K (1 cluster) each. Make subclusters enabled
+# for the top image
+_make_test_img 64K
+IMGPROTO=file IMGFMT=qcow2 TEST_IMG_FILE="$TEST_WRAP" \
+ _make_test_img --no-opts -o extended_l2=true -F "$IMGFMT" -b "$TEST_IMG" \
+ 64K | _filter_img_create
+
+$QEMU_IO -c "write -P 0xaa 0 64k" "$TEST_IMG" | _filter_qemu_io
+
+# Allocate individual subclusters in the top image, and not the whole cluster
+$QEMU_IO -c "write -P 0xbb 28K 2K" -c "write -P 0xcc 34K 2K" "$TEST_WRAP" \
+ | _filter_qemu_io
+
+# Only 2 subclusters should be allocated in the top image at this point
+$QEMU_IMG map "$TEST_WRAP" | _filter_qemu_img_map
+
+# Actual copy-on-read operation
+$QEMU_IO -C -c "read -P 0xaa 30K 4K" "$TEST_WRAP" | _filter_qemu_io
+
+# And here we should have 4 subclusters allocated right in the middle of the
+# top image. Make sure the whole cluster remains unallocated
+$QEMU_IMG map "$TEST_WRAP" | _filter_qemu_img_map
+
+_check_test_img
+
# success, all done
echo '*** done'
status=0
diff --git a/tests/qemu-iotests/197.out b/tests/qemu-iotests/197.out
index ad414c3b0e8be101ae1898479de9a5ccc4569537..8f34a30afea63401d265f4109295c956c6ddec8e 100644
--- a/tests/qemu-iotests/197.out
+++ b/tests/qemu-iotests/197.out
@@ -31,4 +31,28 @@ read 1024/1024 bytes at offset 0
1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
1 KiB (0x400) bytes allocated at offset 0 bytes (0x0)
No errors were found on the image.
+
+=== Copy-on-read with subclusters ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=65536
+Formatting 'TEST_DIR/t.wrap.IMGFMT', fmt=IMGFMT size=65536 backing_file=TEST_DIR/t.IMGFMT backing_fmt=IMGFMT
+wrote 65536/65536 bytes at offset 0
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 2048/2048 bytes at offset 28672
+2 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 2048/2048 bytes at offset 34816
+2 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Offset Length File
+0 0x7000 TEST_DIR/t.IMGFMT
+0x7000 0x800 TEST_DIR/t.wrap.IMGFMT
+0x7800 0x1000 TEST_DIR/t.IMGFMT
+0x8800 0x800 TEST_DIR/t.wrap.IMGFMT
+0x9000 0x7000 TEST_DIR/t.IMGFMT
+read 4096/4096 bytes at offset 30720
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Offset Length File
+0 0x7000 TEST_DIR/t.IMGFMT
+0x7000 0x2000 TEST_DIR/t.wrap.IMGFMT
+0x9000 0x7000 TEST_DIR/t.IMGFMT
+No errors were found on the image.
*** done
diff --git a/util/fdmon-io_uring.c b/util/fdmon-io_uring.c
index 17ec18b7bdd6c9a2d6b74a2ecd3bcd3634216349..16054c5ede3425837d0e7426ce58d72e09e8e2af 100644
--- a/util/fdmon-io_uring.c
+++ b/util/fdmon-io_uring.c
@@ -184,6 +184,7 @@ static void add_poll_remove_sqe(AioContext *ctx, AioHandler *node)
#else
io_uring_prep_poll_remove(sqe, node);
#endif
+ io_uring_sqe_set_data(sqe, NULL);
}
/* Add a timeout that self-cancels when another cqe becomes ready */
@@ -197,6 +198,7 @@ static void add_timeout_sqe(AioContext *ctx, int64_t ns)
sqe = get_sqe(ctx);
io_uring_prep_timeout(sqe, &ts, 1, 0);
+ io_uring_sqe_set_data(sqe, NULL);
}
/* Add sqes from ctx->submit_list for submission */