#include "trace.h"
#include "block/blockjob_int.h"
#include "block/block_int.h"
+#include "block/dirty-bitmap.h"
#include "sysemu/block-backend.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
int max_iov;
bool initial_zeroing_ongoing;
int in_active_write_counter;
+ int64_t active_write_bytes_in_flight;
bool prepared;
bool in_drain;
} MirrorBlockJob;
}
static inline void coroutine_fn
-mirror_wait_for_any_operation(MirrorBlockJob *s, bool active)
+mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s)
{
MirrorOp *op;
QTAILQ_FOREACH(op, &s->ops_in_flight, next) {
- /* Do not wait on pseudo ops, because it may in turn wait on
+ /*
+ * Do not wait on pseudo ops, because it may in turn wait on
* some other operation to start, which may in fact be the
* caller of this function. Since there is only one pseudo op
* at any given time, we will always find some real operation
- * to wait on. */
- if (!op->is_pseudo_op && op->is_in_flight &&
- op->is_active_write == active)
- {
+ * to wait on.
+ * Also, do not wait on active operations, because they do not
+ * use up in-flight slots.
+ */
+ if (!op->is_pseudo_op && op->is_in_flight && !op->is_active_write) {
qemu_co_queue_wait(&op->waiting_requests, NULL);
return;
}
abort();
}
-static inline void coroutine_fn
-mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s)
-{
- /* Only non-active operations use up in-flight slots */
- mirror_wait_for_any_operation(s, false);
-}
-
/* Perform a mirror copy operation.
*
* *op->bytes_handled is set to the number of bytes copied after and
}
bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
+ /*
+ * Wait for concurrent requests to @offset. The next loop will limit the
+ * copied area based on in_flight_bitmap so we only copy an area that does
+ * not overlap with concurrent in-flight requests. Still, we would like to
+ * copy something, so wait until there are at least no more requests to the
+ * very beginning of the area.
+ */
mirror_wait_on_conflicts(NULL, s, offset, 1);
job_pause_point(&s->common.job);
* active layer. */
if (s->base == blk_bs(s->target)) {
if (s->bdev_length > target_length) {
- ret = blk_truncate(s->target, s->bdev_length, false,
- PREALLOC_MODE_OFF, 0, NULL);
+ ret = blk_co_truncate(s->target, s->bdev_length, false,
+ PREALLOC_MODE_OFF, 0, NULL);
if (ret < 0) {
goto immediate_exit;
}
int64_t cnt, delta;
bool should_complete;
- /* Do not start passive operations while there are active
- * writes in progress */
- while (s->in_active_write_counter) {
- mirror_wait_for_any_operation(s, true);
- }
-
if (s->ret < 0) {
ret = s->ret;
goto immediate_exit;
/* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
* the number of bytes currently being processed; together those are
* the current remaining operation length */
- job_progress_set_remaining(&s->common.job, s->bytes_in_flight + cnt);
+ job_progress_set_remaining(&s->common.job,
+ s->bytes_in_flight + cnt +
+ s->active_write_bytes_in_flight);
/* Note that even when no rate limit is applied we need to yield
* periodically with no pending I/O so that bdrv_drain_all() returns.
s->in_drain = true;
bdrv_drained_begin(bs);
+
+ /* Must be zero because we are drained */
+ assert(s->in_active_write_counter == 0);
+
cnt = bdrv_get_dirty_count(s->dirty_bitmap);
if (cnt > 0 || mirror_flush(s) < 0) {
bdrv_drained_end(bs);
}
job_progress_increase_remaining(&job->common.job, bytes);
+ job->active_write_bytes_in_flight += bytes;
switch (method) {
case MIRROR_METHOD_COPY:
abort();
}
+ job->active_write_bytes_in_flight -= bytes;
if (ret >= 0) {
job_progress_update(&job->common.job, bytes);
} else {
s->in_active_write_counter++;
+ /*
+ * Wait for concurrent requests affecting the area. If there are already
+ * running requests that are copying off now-to-be stale data in the area,
+ * we must wait for them to finish before we begin writing fresh data to the
+ * target so that the write operations appear in the correct order.
+ * Note that background requests (see mirror_iteration()) in contrast only
+ * wait for conflicting requests at the start of the dirty area, and then
+ * (based on the in_flight_bitmap) truncate the area to copy so it will not
+ * conflict with any requests beyond that. For active writes, however, we
+ * cannot truncate that area. The request from our parent must be blocked
+ * until the area is copied in full. Therefore, we must wait for the whole
+ * area to become free of concurrent requests.
+ */
mirror_wait_on_conflicts(op, s, offset, bytes);
bitmap_set(s->in_flight_bitmap, start_chunk, end_chunk - start_chunk);
MirrorOp *op = NULL;
MirrorBDSOpaque *s = bs->opaque;
int ret = 0;
- bool copy_to_target;
+ bool copy_to_target = false;
- copy_to_target = s->job->ret >= 0 &&
- !job_is_cancelled(&s->job->common.job) &&
- s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
+ if (s->job) {
+ copy_to_target = s->job->ret >= 0 &&
+ !job_is_cancelled(&s->job->common.job) &&
+ s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
+ }
if (copy_to_target) {
op = active_write_prepare(s->job, offset, bytes);
QEMUIOVector bounce_qiov;
void *bounce_buf;
int ret = 0;
- bool copy_to_target;
+ bool copy_to_target = false;
- copy_to_target = s->job->ret >= 0 &&
- !job_is_cancelled(&s->job->common.job) &&
- s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
+ if (s->job) {
+ copy_to_target = s->job->ret >= 0 &&
+ !job_is_cancelled(&s->job->common.job) &&
+ s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
+ }
if (copy_to_target) {
/* The guest might concurrently modify the data to write; but
qemu_iovec_init(&bounce_qiov, 1);
qemu_iovec_add(&bounce_qiov, bounce_buf, bytes);
qiov = &bounce_qiov;
+
+ flags &= ~BDRV_REQ_REGISTERED_BUF;
}
ret = bdrv_mirror_top_do_write(bs, MIRROR_METHOD_COPY, offset, bytes, qiov,
.bdrv_child_perm = bdrv_mirror_top_child_perm,
.is_filter = true,
+ .filtered_child_is_backing = true,
};
static BlockJob *mirror_start_job(
projects / mirror_qemu.git / blobdiff