* [Qemu-devel] [PATCH v4 1/3] block: Fix parameter checking in bdrv_co_copy_range_internal
2018-07-03 2:37 [Qemu-devel] [PATCH v4 0/3] backup: Use copy offloading Fam Zheng
@ 2018-07-03 2:37 ` Fam Zheng
2018-07-03 3:23 ` Jeff Cody
2018-07-03 2:37 ` [Qemu-devel] [PATCH v4 2/3] block: Honour BDRV_REQ_NO_SERIALISING in copy range Fam Zheng
` (2 subsequent siblings)
3 siblings, 1 reply; 6+ messages in thread
From: Fam Zheng @ 2018-07-03 2:37 UTC (permalink / raw)
To: qemu-devel
Cc: qemu-block, Fam Zheng, Stefan Hajnoczi, Kevin Wolf, Max Reitz,
Jeff Cody
src may be NULL if BDRV_REQ_ZERO_WRITE flag is set, in this case only
check dst and dst->bs. This bug was introduced when moving in the
request tracking code from bdrv_co_copy_range, in 37aec7d75eb.
This especially fixes the possible segfault when initializing src_bs
with a NULL src.
Signed-off-by: Fam Zheng <famz@redhat.com>
---
block/io.c | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)
diff --git a/block/io.c b/block/io.c
index 7035b78a20..b8845708d7 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2897,18 +2897,11 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,
bool recurse_src)
{
BdrvTrackedRequest src_req, dst_req;
- BlockDriverState *src_bs = src->bs;
- BlockDriverState *dst_bs = dst->bs;
int ret;
- if (!src || !dst || !src->bs || !dst->bs) {
+ if (!dst || !dst->bs) {
return -ENOMEDIUM;
}
- ret = bdrv_check_byte_request(src->bs, src_offset, bytes);
- if (ret) {
- return ret;
- }
-
ret = bdrv_check_byte_request(dst->bs, dst_offset, bytes);
if (ret) {
return ret;
@@ -2917,16 +2910,24 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,
return bdrv_co_pwrite_zeroes(dst, dst_offset, bytes, flags);
}
+ if (!src || !src->bs) {
+ return -ENOMEDIUM;
+ }
+ ret = bdrv_check_byte_request(src->bs, src_offset, bytes);
+ if (ret) {
+ return ret;
+ }
+
if (!src->bs->drv->bdrv_co_copy_range_from
|| !dst->bs->drv->bdrv_co_copy_range_to
|| src->bs->encrypted || dst->bs->encrypted) {
return -ENOTSUP;
}
- bdrv_inc_in_flight(src_bs);
- bdrv_inc_in_flight(dst_bs);
- tracked_request_begin(&src_req, src_bs, src_offset,
+ bdrv_inc_in_flight(src->bs);
+ bdrv_inc_in_flight(dst->bs);
+ tracked_request_begin(&src_req, src->bs, src_offset,
bytes, BDRV_TRACKED_READ);
- tracked_request_begin(&dst_req, dst_bs, dst_offset,
+ tracked_request_begin(&dst_req, dst->bs, dst_offset,
bytes, BDRV_TRACKED_WRITE);
wait_serialising_requests(&src_req);
@@ -2944,8 +2945,8 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,
}
tracked_request_end(&src_req);
tracked_request_end(&dst_req);
- bdrv_dec_in_flight(src_bs);
- bdrv_dec_in_flight(dst_bs);
+ bdrv_dec_in_flight(src->bs);
+ bdrv_dec_in_flight(dst->bs);
return ret;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [Qemu-devel] [PATCH v4 3/3] backup: Use copy offloading
2018-07-03 2:37 [Qemu-devel] [PATCH v4 0/3] backup: Use copy offloading Fam Zheng
2018-07-03 2:37 ` [Qemu-devel] [PATCH v4 1/3] block: Fix parameter checking in bdrv_co_copy_range_internal Fam Zheng
2018-07-03 2:37 ` [Qemu-devel] [PATCH v4 2/3] block: Honour BDRV_REQ_NO_SERIALISING in copy range Fam Zheng
@ 2018-07-03 2:37 ` Fam Zheng
2018-07-03 3:25 ` [Qemu-devel] [PATCH v4 0/3] " Jeff Cody
3 siblings, 0 replies; 6+ messages in thread
From: Fam Zheng @ 2018-07-03 2:37 UTC (permalink / raw)
To: qemu-devel
Cc: qemu-block, Fam Zheng, Stefan Hajnoczi, Kevin Wolf, Max Reitz,
Jeff Cody
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.
Then, as Kevin pointed out, both this and qemu-img convert can benefit
from a local check if one request fails because of, for example, the
offset is beyond EOF, but another may well be accepted by the protocol
layer. This will be implemented separately.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
block/backup.c | 150 ++++++++++++++++++++++++++++++++-------------
block/trace-events | 1 +
2 files changed, 110 insertions(+), 41 deletions(-)
diff --git a/block/backup.c b/block/backup.c
index d18be40caf..81895ddbe2 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;
@@ -86,19 +88,101 @@ 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 coroutine_fn 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) {
+ 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 +194,38 @@ 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 +727,12 @@ 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"
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread