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 <f...@redhat.com>
---
block/backup.c | 93 +++++++++++++++++++++++++++++++++++-------------------
block/trace-events | 1 +
2 files changed, 62 insertions(+), 32 deletions(-)
diff --git a/block/backup.c b/block/backup.c
index 4e228e959b..ab189693f4 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -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;
@@ -111,49 +113,70 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
cow_request_begin(&cow_request, job, start, end);
for (; start < end; start += job->cluster_size) {
+retry:
if (!hbitmap_get(job->copy_bitmap, start / job->cluster_size)) {
trace_backup_do_cow_skip(job, start);
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) {
+ hbitmap_reset(job->copy_bitmap, start / job->cluster_size, 1);
+ n = MIN(job->cluster_size, job->len - start);
+ if (!bounce_buffer) {
+ bounce_buffer = blk_blockalign(blk, job->cluster_size);
}
- hbitmap_set(job->copy_bitmap, start / job->cluster_size, 1);
- goto out;
- }
+ iov.iov_base = bounce_buffer;
+ iov.iov_len = n;
+ qemu_iovec_init_external(&bounce_qiov, &iov, 1);
- 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);
+ 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;
+ }
+ 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 (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;
+ }
} else {
- ret = blk_co_pwritev(job->target, start,
- bounce_qiov.size, &bounce_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;
+ int nr_clusters;
+
+ assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_size));
+ n = MIN(job->copy_range_size, job->len - start);
+ n = MIN(bytes, n);
+ nr_clusters = DIV_ROUND_UP(n, job->cluster_size);
+ hbitmap_reset(job->copy_bitmap, start / job->cluster_size,
+ nr_clusters);
+ ret = blk_co_copy_range(blk, start, job->target, start, n,
+ 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);
+ /* Retry with bounce buffer. */
+ goto retry;
}
- hbitmap_set(job->copy_bitmap, start / job->cluster_size, 1);
- goto out;
}
/* Publish progress, guest I/O counts as progress too. Note that the
@@ -665,6 +688,12 @@ 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,
diff --git a/block/trace-events b/block/trace-events
index 2d59b53fd3..c35287b48a 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -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"
--
2.14.3
