@@ -45,6 +45,8 @@ typedef struct BackupBlockJob {
QLIST_HEAD(, CowRequest) inflight_reqs;
HBitmap *copy_bitmap;
+ bool use_copy_range;
+ int64_t copy_range_size;
} BackupBlockJob;
static const BlockJobDriver backup_job_driver;
@@ -86,19 +88,102 @@ static void cow_request_end(CowRequest *req)
qemu_co_queue_restart_all(&req->wait_queue);
}
+/* Copy range to target with a bounce buffer and return the bytes copied. If
+ * error occured, return a negative error number */
+static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job,
+ int64_t start,
+ int64_t end,
+ bool is_write_notifier,
+ bool *error_is_read,
+ void **bounce_buffer)
+{
+ int ret;
+ struct iovec iov;
+ QEMUIOVector qiov;
+ BlockBackend *blk = job->common.blk;
+ int nbytes;
+
+ hbitmap_reset(job->copy_bitmap, start / job->cluster_size, 1);
+ nbytes = MIN(job->cluster_size, job->len - start);
+ if (!*bounce_buffer) {
+ *bounce_buffer = blk_blockalign(blk, job->cluster_size);
+ }
+ iov.iov_base = *bounce_buffer;
+ iov.iov_len = nbytes;
+ qemu_iovec_init_external(&qiov, &iov, 1);
+
+ ret = blk_co_preadv(blk, start, qiov.size, &qiov,
+ is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
+ if (ret < 0) {
+ trace_backup_do_cow_read_fail(job, start, ret);
+ if (error_is_read) {
+ *error_is_read = true;
+ }
+ goto fail;
+ }
+
+ if (qemu_iovec_is_zero(&qiov)) {
+ ret = blk_co_pwrite_zeroes(job->target, start,
+ qiov.size, BDRV_REQ_MAY_UNMAP);
+ } else {
+ ret = blk_co_pwritev(job->target, start,
+ qiov.size, &qiov,
+ job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0);
+ }
+ if (ret < 0) {
+ trace_backup_do_cow_write_fail(job, start, ret);
+ if (error_is_read) {
+ *error_is_read = false;
+ }
+ goto fail;
+ }
+
+ return nbytes;
+fail:
+ hbitmap_set(job->copy_bitmap, start / job->cluster_size, 1);
+ return ret;
+
+}
+
+/* Copy range to target and return the bytes copied. If error occured, return a
+ * negative error number. */
+static int backup_cow_with_offload(BackupBlockJob *job,
+ int64_t start,
+ int64_t end,
+ bool is_write_notifier)
+{
+ int ret;
+ int nr_clusters;
+ BlockBackend *blk = job->common.blk;
+ int nbytes;
+
+ assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_size));
+ nbytes = MIN(job->copy_range_size, end - start);
+ nr_clusters = DIV_ROUND_UP(nbytes, job->cluster_size);
+ hbitmap_reset(job->copy_bitmap, start / job->cluster_size,
+ nr_clusters);
+ ret = blk_co_copy_range(blk, start, job->target, start, nbytes,
+ is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
+ if (ret < 0) {
+ job->use_copy_range = false;
+ trace_backup_do_cow_copy_range_fail(job, start, ret);
+ hbitmap_set(job->copy_bitmap, start / job->cluster_size,
+ nr_clusters);
+ return ret;
+ }
+
+ return nbytes;
+}
+
static int coroutine_fn backup_do_cow(BackupBlockJob *job,
int64_t offset, uint64_t bytes,
bool *error_is_read,
bool is_write_notifier)
{
- BlockBackend *blk = job->common.blk;
CowRequest cow_request;
- struct iovec iov;
- QEMUIOVector bounce_qiov;
- void *bounce_buffer = NULL;
int ret = 0;
int64_t start, end; /* bytes */
- int n; /* bytes */
+ void *bounce_buffer = NULL;
qemu_co_rwlock_rdlock(&job->flush_rwlock);
@@ -110,60 +195,38 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
wait_for_overlapping_requests(job, start, end);
cow_request_begin(&cow_request, job, start, end);
- for (; start < end; start += job->cluster_size) {
+ while (start < end) {
if (!hbitmap_get(job->copy_bitmap, start / job->cluster_size)) {
trace_backup_do_cow_skip(job, start);
+ start += job->cluster_size;
continue; /* already copied */
}
- hbitmap_reset(job->copy_bitmap, start / job->cluster_size, 1);
trace_backup_do_cow_process(job, start);
- n = MIN(job->cluster_size, job->len - start);
-
- if (!bounce_buffer) {
- bounce_buffer = blk_blockalign(blk, job->cluster_size);
- }
- iov.iov_base = bounce_buffer;
- iov.iov_len = n;
- qemu_iovec_init_external(&bounce_qiov, &iov, 1);
-
- ret = blk_co_preadv(blk, start, bounce_qiov.size, &bounce_qiov,
- is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
- if (ret < 0) {
- trace_backup_do_cow_read_fail(job, start, ret);
- if (error_is_read) {
- *error_is_read = true;
+ if (job->use_copy_range) {
+ ret = backup_cow_with_offload(job, start, end, is_write_notifier);
+ if (ret < 0) {
+ job->use_copy_range = false;
}
- hbitmap_set(job->copy_bitmap, start / job->cluster_size, 1);
- goto out;
}
-
- if (buffer_is_zero(iov.iov_base, iov.iov_len)) {
- ret = blk_co_pwrite_zeroes(job->target, start,
- bounce_qiov.size, BDRV_REQ_MAY_UNMAP);
- } else {
- ret = blk_co_pwritev(job->target, start,
- bounce_qiov.size, &bounce_qiov,
- job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0);
+ if (!job->use_copy_range) {
+ ret = backup_cow_with_bounce_buffer(job, start, end, is_write_notifier,
+ error_is_read, &bounce_buffer);
}
if (ret < 0) {
- trace_backup_do_cow_write_fail(job, start, ret);
- if (error_is_read) {
- *error_is_read = false;
- }
- hbitmap_set(job->copy_bitmap, start / job->cluster_size, 1);
- goto out;
+ break;
}
/* Publish progress, guest I/O counts as progress too. Note that the
* offset field is an opaque progress value, it is not a disk offset.
*/
- job->bytes_read += n;
- job_progress_update(&job->common.job, n);
+ start += ret;
+ job->bytes_read += ret;
+ job_progress_update(&job->common.job, ret);
+ ret = 0;
}
-out:
if (bounce_buffer) {
qemu_vfree(bounce_buffer);
}
@@ -665,6 +728,12 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
} else {
job->cluster_size = MAX(BACKUP_CLUSTER_SIZE_DEFAULT, bdi.cluster_size);
}
+ job->use_copy_range = true;
+ job->copy_range_size = MIN_NON_ZERO(blk_get_max_transfer(job->common.blk),
+ blk_get_max_transfer(job->target));
+ job->copy_range_size = MAX(job->cluster_size,
+ QEMU_ALIGN_UP(job->copy_range_size,
+ job->cluster_size));
/* Required permissions are already taken with target's blk_new() */
block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
@@ -42,6 +42,7 @@ backup_do_cow_skip(void *job, int64_t start) "job %p start %"PRId64
backup_do_cow_process(void *job, int64_t start) "job %p start %"PRId64
backup_do_cow_read_fail(void *job, int64_t start, int ret) "job %p start %"PRId64" ret %d"
backup_do_cow_write_fail(void *job, int64_t start, int ret) "job %p start %"PRId64" ret %d"
+backup_do_cow_copy_range_fail(void *job, int64_t start, int ret) "job %p start %"PRId64" ret %d"
# blockdev.c
qmp_block_job_cancel(void *job) "job %p"
The implementation is similar to the 'qemu-img convert'. In the beginning of the job, offloaded copy is attempted. If it fails, further I/O will go through the existing bounce buffer code path. Signed-off-by: Fam Zheng <famz@redhat.com> --- block/backup.c | 151 +++++++++++++++++++++++++++++++++------------ block/trace-events | 1 + 2 files changed, 111 insertions(+), 41 deletions(-)