Merge remote-tracking branch 'remotes/cody/tags/block-pull-request' into staging

# gpg: Signature made Tue 03 Jul 2018 04:42:11 BST
# gpg:                using RSA key BDBE7B27C0DE3057
# gpg: Good signature from "Jeffrey Cody <jcody@redhat.com>"
# gpg:                 aka "Jeffrey Cody <jeff@codyprime.org>"
# gpg:                 aka "Jeffrey Cody <codyprime@gmail.com>"
# Primary key fingerprint: 9957 4B4D 3474 90E7 9D98  D624 BDBE 7B27 C0DE 3057

* remotes/cody/tags/block-pull-request:
  backup: Use copy offloading
  block: Honour BDRV_REQ_NO_SERIALISING in copy range
  block: Fix parameter checking in bdrv_co_copy_range_internal
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

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,

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;
@@ -2917,20 +2910,30 @@ 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);
-    wait_serialising_requests(&dst_req);
+    if (!(flags & BDRV_REQ_NO_SERIALISING)) {
+        wait_serialising_requests(&src_req);
+        wait_serialising_requests(&dst_req);
+    }
     if (recurse_src) {
         ret = src->bs->drv->bdrv_co_copy_range_from(src->bs,
                                                     src, src_offset,
@@ -2944,8 +2947,8 @@ 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;
 }
 

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"

include/block/block.h

@@ -659,13 +659,14 @@ void bdrv_unregister_buf(BlockDriverState *bs, void *host);
  * @dst: Destination child to copy data to
  * @dst_offset: offset in @dst image to write data
  * @bytes: number of bytes to copy
- * @flags: request flags. Must be one of:
- *         0 - actually read data from src;
+ * @flags: request flags. Supported flags:
  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
  *                               write on @dst as if bdrv_co_pwrite_zeroes is
  *                               called. Used to simplify caller code, or
  *                               during BlockDriver.bdrv_co_copy_range_from()
  *                               recursion.
+ *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
+ *                                   requests currently in flight.
  *
  * Returns: 0 if succeeded; negative error code if failed.
  **/