Signed-off-by: Max Reitz <[email protected]>
---
block/mirror.c | 54 +++++++++++++++++++++++++++++++++-----------------
1 file changed, 36 insertions(+), 18 deletions(-)
diff --git a/block/mirror.c b/block/mirror.c
index c28b6159d5..34cb8293b2 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -305,42 +305,60 @@ static inline void coroutine_fn
mirror_co_wait_for_any_operation(s, false);
}
-/* Perform a mirror copy operation.
+/*
+ * Restrict *bytes to how much we can actually handle, and align the
+ * [*offset, *bytes] range to clusters if COW is needed.
*
- * *op->bytes_handled is set to the number of bytes copied after and
+ * *bytes_handled is set to the number of bytes copied after and
* including offset, excluding any bytes copied prior to offset due
- * to alignment. This will be op->bytes if no alignment is necessary,
- * or (new_end - op->offset) if the tail is rounded up or down due to
+ * to alignment. This will be *bytes if no alignment is necessary, or
+ * (new_end - *offset) if the tail is rounded up or down due to
* alignment or buffer limit.
*/
-static void coroutine_fn mirror_co_read(void *opaque)
+static void mirror_align_for_copy(MirrorBlockJob *s,
+ int64_t *offset, uint64_t *bytes,
+ int64_t *bytes_handled)
{
- MirrorOp *op = opaque;
- MirrorBlockJob *s = op->s;
- int nb_chunks;
- uint64_t ret;
uint64_t max_bytes;
max_bytes = s->granularity * s->max_iov;
/* We can only handle as much as buf_size at a time. */
- op->bytes = MIN(s->buf_size, MIN(max_bytes, op->bytes));
- assert(op->bytes);
- assert(op->bytes < BDRV_REQUEST_MAX_BYTES);
- *op->bytes_handled = op->bytes;
+ *bytes = MIN(s->buf_size, MIN(max_bytes, *bytes));
+ assert(*bytes);
+ assert(*bytes < BDRV_REQUEST_MAX_BYTES);
+ *bytes_handled = *bytes;
if (s->cow_bitmap) {
- *op->bytes_handled += mirror_cow_align(s, &op->offset, &op->bytes);
+ *bytes_handled += mirror_cow_align(s, offset, bytes);
}
/* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */
- assert(*op->bytes_handled <= UINT_MAX);
- assert(op->bytes <= s->buf_size);
+ assert(*bytes_handled <= UINT_MAX);
+ assert(*bytes <= s->buf_size);
/* The offset is granularity-aligned because:
* 1) Caller passes in aligned values;
* 2) mirror_cow_align is used only when target cluster is larger. */
- assert(QEMU_IS_ALIGNED(op->offset, s->granularity));
+ assert(QEMU_IS_ALIGNED(*offset, s->granularity));
/* The range is sector-aligned, since bdrv_getlength() rounds up. */
- assert(QEMU_IS_ALIGNED(op->bytes, BDRV_SECTOR_SIZE));
+ assert(QEMU_IS_ALIGNED(*bytes, BDRV_SECTOR_SIZE));
+}
+
+/* Perform a mirror copy operation.
+ *
+ * *op->bytes_handled is set to the number of bytes copied after and
+ * including offset, excluding any bytes copied prior to offset due
+ * to alignment. This will be op->bytes if no alignment is necessary,
+ * or (new_end - op->offset) if the tail is rounded up or down due to
+ * alignment or buffer limit.
+ */
+static void coroutine_fn mirror_co_read(void *opaque)
+{
+ MirrorOp *op = opaque;
+ MirrorBlockJob *s = op->s;
+ int nb_chunks;
+ uint64_t ret;
+
+ mirror_align_for_copy(s, &op->offset, &op->bytes, op->bytes_handled);
nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity);
while (s->buf_free_count < nb_chunks) {
--
2.17.1
