Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2019-06-14' into staging

Block patches:
- Allow blockdev-backup from nodes that are not in qemu's main AIO
  context to newly added nodes
- Add salvaging mode to qemu-img convert
- Minor fixes to tests, documentation, and for less Valgrind annoyance

# gpg: Signature made Fri 14 Jun 2019 14:38:11 BST
# gpg:                using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40
# gpg:                issuer "mreitz@redhat.com"
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full]
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/maxreitz/tags/pull-block-2019-06-14:
  iotests: Test qemu-img convert -C --salvage
  iotests: Test qemu-img convert --salvage
  blkdebug: Inject errors on .bdrv_co_block_status()
  blkdebug: Add "none" event
  blkdebug: Add @iotype error option
  qemu-img: Add salvaging mode to convert
  qemu-img: Move quiet into ImgConvertState
  blockdev: Overlays are not snapshots
  qapi/block-core: Overlays are not snapshots
  qemu-img: Fix options leakage in img_rebase()
  iotests: restrict 254 to support only qcow2
  hw/block/fdc: floppy command FIFO memory initialization
  iotests: Fix intermittent failure in 219
  iotests: Filter 175's allocation information
  event_match: always match on None value
  iotests: add iotest 256 for testing blockdev-backup across iothread contexts
  iotests.py: rewrite run_job to be pickier
  QEMUMachine: add events_wait method
  iotests.py: do not use infinite waits
  blockdev-backup: don't check aio_context too early

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

13 files changed, 538 insertions, 41 deletions

diff --git a/tests/qemu-iotests/082 b/tests/qemu-iotests/082
index bbbdf555dc..3286c2c6db 100755
--- a/tests/qemu-iotests/082
+++ b/tests/qemu-iotests/082
@@ -162,6 +162,7 @@ echo === convert: -C and other options ===
 run_qemu_img convert -C -S 4k -O $IMGFMT "$TEST_IMG" "$TEST_IMG".target
 run_qemu_img convert -C -S 8k -O $IMGFMT "$TEST_IMG" "$TEST_IMG".target
 run_qemu_img convert -C -c -O $IMGFMT "$TEST_IMG" "$TEST_IMG".target
+run_qemu_img convert -C --salvage -O $IMGFMT "$TEST_IMG" "$TEST_IMG".target
 
 echo
 echo === amend: Options specified more than once ===
diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out
index 7e25706813..58de358b38 100644
--- a/tests/qemu-iotests/082.out
+++ b/tests/qemu-iotests/082.out
@@ -567,6 +567,9 @@ qemu-img: Cannot enable copy offloading when -S is used
 Testing: convert -C -c -O qcow2 TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.target
 qemu-img: Cannot enable copy offloading when -c is used
 
+Testing: convert -C --salvage -O qcow2 TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.target
+qemu-img: Cannot use copy offloading in salvaging mode
+
 === amend: Options specified more than once ===
 
 Testing: amend -f foo -f qcow2 -o lazy_refcounts=on TEST_DIR/t.qcow2
diff --git a/tests/qemu-iotests/085.out b/tests/qemu-iotests/085.out
index 6edf107f55..2a5f256cd3 100644
--- a/tests/qemu-iotests/085.out
+++ b/tests/qemu-iotests/085.out
@@ -64,13 +64,13 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/
 
 === Invalid command - cannot create a snapshot using a file BDS ===
 
-{"error": {"class": "GenericError", "desc": "The snapshot does not support backing images"}}
+{"error": {"class": "GenericError", "desc": "The overlay does not support backing images"}}
 
 === Invalid command - snapshot node used as active layer ===
 
-{"error": {"class": "GenericError", "desc": "The snapshot is already in use"}}
-{"error": {"class": "GenericError", "desc": "The snapshot is already in use"}}
-{"error": {"class": "GenericError", "desc": "The snapshot is already in use"}}
+{"error": {"class": "GenericError", "desc": "The overlay is already in use"}}
+{"error": {"class": "GenericError", "desc": "The overlay is already in use"}}
+{"error": {"class": "GenericError", "desc": "The overlay is already in use"}}
 
 === Invalid command - snapshot node used as backing hd ===
 
@@ -81,7 +81,7 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/
 Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=134217728
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/t.IMGFMT.base
 {"return": {}}
-{"error": {"class": "GenericError", "desc": "The snapshot already has a backing image"}}
+{"error": {"class": "GenericError", "desc": "The overlay already has a backing image"}}
 
 === Invalid command - The node does not exist ===
 
diff --git a/tests/qemu-iotests/175 b/tests/qemu-iotests/175
index d0ffc495c2..51e62c8276 100755
--- a/tests/qemu-iotests/175
+++ b/tests/qemu-iotests/175
@@ -28,10 +28,25 @@ status=1	# failure is the default!
 
 _cleanup()
 {
-	_cleanup_test_img
+    _cleanup_test_img
+    rm -f "$TEST_DIR/empty"
 }
 trap "_cleanup; exit \$status" 0 1 2 3 15
 
+# Some file systems sometimes allocate extra blocks independently of
+# the file size.  This function hides the resulting difference in the
+# stat -c '%b' output.
+# Parameter 1: Number of blocks an empty file occupies
+# Parameter 2: Image size in bytes
+_filter_blocks()
+{
+    extra_blocks=$1
+    img_size=$2
+
+    sed -e "s/blocks=$extra_blocks\\(\$\\|[^0-9]\\)/nothing allocated/" \
+        -e "s/blocks=$((extra_blocks + img_size / 512))\\(\$\\|[^0-9]\\)/everything allocated/"
+}
+
 # get standard environment, filters and checks
 . ./common.rc
 . ./common.filter
@@ -40,18 +55,21 @@ _supported_fmt raw
 _supported_proto file
 _supported_os Linux
 
-size=1m
+size=$((1 * 1024 * 1024))
+
+touch "$TEST_DIR/empty"
+extra_blocks=$(stat -c '%b' "$TEST_DIR/empty")
 
 echo
 echo "== creating image with default preallocation =="
 _make_test_img $size | _filter_imgfmt
-stat -c "size=%s, blocks=%b" $TEST_IMG
+stat -c "size=%s, blocks=%b" $TEST_IMG | _filter_blocks $extra_blocks $size
 
 for mode in off full falloc; do
     echo
     echo "== creating image with preallocation $mode =="
     IMGOPTS=preallocation=$mode _make_test_img $size | _filter_imgfmt
-    stat -c "size=%s, blocks=%b" $TEST_IMG
+    stat -c "size=%s, blocks=%b" $TEST_IMG | _filter_blocks $extra_blocks $size
 done
 
 # success, all done
diff --git a/tests/qemu-iotests/175.out b/tests/qemu-iotests/175.out
index 76c02c6a57..6d9a5ed84e 100644
--- a/tests/qemu-iotests/175.out
+++ b/tests/qemu-iotests/175.out
@@ -2,17 +2,17 @@ QA output created by 175
 
 == creating image with default preallocation ==
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
-size=1048576, blocks=0
+size=1048576, nothing allocated
 
 == creating image with preallocation off ==
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 preallocation=off
-size=1048576, blocks=0
+size=1048576, nothing allocated
 
 == creating image with preallocation full ==
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 preallocation=full
-size=1048576, blocks=2048
+size=1048576, everything allocated
 
 == creating image with preallocation falloc ==
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 preallocation=falloc
-size=1048576, blocks=2048
+size=1048576, everything allocated
  *** done
diff --git a/tests/qemu-iotests/219 b/tests/qemu-iotests/219
index c03bbdb294..e0c51662c0 100755
--- a/tests/qemu-iotests/219
+++ b/tests/qemu-iotests/219
@@ -23,6 +23,8 @@ import iotests
 
 iotests.verify_image_format(supported_fmts=['qcow2'])
 
+img_size = 4 * 1024 * 1024
+
 def pause_wait(vm, job_id):
     with iotests.Timeout(3, "Timeout waiting for job to pause"):
         while True:
@@ -62,6 +64,8 @@ def test_pause_resume(vm):
                 iotests.log(vm.qmp('query-jobs'))
 
 def test_job_lifecycle(vm, job, job_args, has_ready=False):
+    global img_size
+
     iotests.log('')
     iotests.log('')
     iotests.log('Starting block job: %s (auto-finalize: %s; auto-dismiss: %s)' %
@@ -84,6 +88,10 @@ def test_job_lifecycle(vm, job, job_args, has_ready=False):
     iotests.log(iotests.filter_qmp_event(vm.event_wait('JOB_STATUS_CHANGE')))
     iotests.log(iotests.filter_qmp_event(vm.event_wait('JOB_STATUS_CHANGE')))
 
+    # Wait for total-progress to stabilize
+    while vm.qmp('query-jobs')['return'][0]['total-progress'] < img_size:
+        pass
+
     # RUNNING state:
     # pause/resume should work, complete/finalize/dismiss should error out
     iotests.log('')
@@ -173,9 +181,8 @@ with iotests.FilePath('disk.img') as disk_path, \
      iotests.FilePath('copy.img') as copy_path, \
      iotests.VM() as vm:
 
-    img_size = '4M'
-    iotests.qemu_img_create('-f', iotests.imgfmt, disk_path, img_size)
-    iotests.qemu_io('-c', 'write 0 %s' % (img_size),
+    iotests.qemu_img_create('-f', iotests.imgfmt, disk_path, str(img_size))
+    iotests.qemu_io('-c', 'write 0 %i' % (img_size),
                     '-f', iotests.imgfmt, disk_path)
 
     iotests.log('Launching VM...')
diff --git a/tests/qemu-iotests/251 b/tests/qemu-iotests/251
new file mode 100755
index 0000000000..13f85de9cd
--- /dev/null
+++ b/tests/qemu-iotests/251
@@ -0,0 +1,170 @@
+#!/usr/bin/env bash
+#
+# Test qemu-img convert --salvage
+#
+# Copyright (C) 2019 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=mreitz@redhat.com
+
+seq=$(basename $0)
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.qemu
+
+_supported_fmt generic
+_supported_proto file
+_supported_os Linux
+
+if [ "$IMGOPTSSYNTAX" = "true" ]; then
+    # We use json:{} filenames here, so we cannot work with additional options.
+    _unsupported_fmt $IMGFMT
+else
+    # With VDI, the output is ordered differently.  Just disable it.
+    _unsupported_fmt vdi
+fi
+
+
+TEST_IMG="$TEST_IMG.orig" _make_test_img 64M
+
+$QEMU_IO -c 'write -P 42 0 64M' "$TEST_IMG.orig" | _filter_qemu_io
+
+
+sector_size=512
+
+# Offsets on which to fail block-status.  Keep in ascending order so
+# the indexing done by _filter_offsets will appear in ascending order
+# in the output as well.
+status_fail_offsets="$((16 * 1024 * 1024 + 8192))
+                     $((33 * 1024 * 1024 + 512))"
+
+# Offsets on which to fail reads.  Keep in ascending order for the
+# same reason.
+# The second element is shared with $status_fail_offsets on purpose.
+# Starting with the third element, we test what happens when a
+# continuous range of sectors is inaccessible.
+read_fail_offsets="$((32 * 1024 * 1024 - 65536))
+                   $((33 * 1024 * 1024 + 512))
+                   $(seq $((34 * 1024 * 1024)) $sector_size \
+                         $((34 * 1024 * 1024 + 4096 - $sector_size)))"
+
+
+# blkdebug must be above the format layer so it can intercept all
+# block-status events
+source_img="json:{'driver': 'blkdebug',
+                  'image': {
+                      'driver': '$IMGFMT',
+                      'file': {
+                          'driver': 'file',
+                          'filename': '$TEST_IMG.orig'
+                      }
+                  },
+                  'inject-error': ["
+
+for ofs in $status_fail_offsets
+do
+    source_img+="{ 'event': 'none',
+                   'iotype': 'block-status',
+                   'errno': 5,
+                   'sector': $((ofs / sector_size)) },"
+done
+
+for ofs in $read_fail_offsets
+do
+    source_img+="{ 'event': 'none',
+                   'iotype': 'read',
+                   'errno': 5,
+                   'sector': $((ofs / sector_size)) },"
+done
+
+# Remove the trailing comma and terminate @inject-error and json:{}
+source_img="${source_img%,} ] }"
+
+
+echo
+
+
+_filter_offsets() {
+    filters=
+
+    index=0
+    for ofs in $1
+    do
+        filters+=" -e s/$ofs/status_fail_offset_$index/"
+        index=$((index + 1))
+    done
+
+    index=0
+    for ofs in $2
+    do
+        filters+=" -e s/$ofs/read_fail_offset_$index/"
+        index=$((index + 1))
+    done
+
+    sed $filters
+}
+
+# While determining the number of allocated sectors in the input
+# image, we should see one block status warning per element of
+# $status_fail_offsets.
+#
+# Then, the image is read.  Since the block status is queried in
+# basically the same way, the same warnings as in the previous step
+# should reappear.  Interleaved with those we should see a read
+# warning per element of $read_fail_offsets.
+# Note that $read_fail_offsets and $status_fail_offsets share an
+# element (read_fail_offset_1 == status_fail_offset_1), so
+# "status_fail_offset_1" in the output is the same as
+# "read_fail_offset_1".
+$QEMU_IMG convert --salvage "$source_img" "$TEST_IMG" 2>&1 \
+    | _filter_offsets "$status_fail_offsets" "$read_fail_offsets"
+
+echo
+
+# The offsets where the block status could not be determined should
+# have been treated as containing data and thus should be correct in
+# the output image.
+# The offsets where reading failed altogether should be 0.  Make them
+# 0 in the input image, too, so we can compare both images.
+for ofs in $read_fail_offsets
+do
+    $QEMU_IO -c "write -z $ofs $sector_size" "$TEST_IMG.orig" \
+        | _filter_qemu_io \
+        | _filter_offsets '' "$read_fail_offsets"
+done
+
+echo
+
+# These should be equal now.
+$QEMU_IMG compare "$TEST_IMG.orig" "$TEST_IMG"
+
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/251.out b/tests/qemu-iotests/251.out
new file mode 100644
index 0000000000..75b8796aad
--- /dev/null
+++ b/tests/qemu-iotests/251.out
@@ -0,0 +1,43 @@
+QA output created by 251
+Formatting 'TEST_DIR/t.IMGFMT.orig', fmt=IMGFMT size=67108864
+wrote 67108864/67108864 bytes at offset 0
+64 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+qemu-img: warning: error while reading block status at offset status_fail_offset_0: Input/output error
+qemu-img: warning: error while reading block status at offset status_fail_offset_1: Input/output error
+qemu-img: warning: error while reading block status at offset status_fail_offset_0: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_0: Input/output error
+qemu-img: warning: error while reading block status at offset status_fail_offset_1: Input/output error
+qemu-img: warning: error while reading offset status_fail_offset_1: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_2: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_3: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_4: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_5: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_6: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_7: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_8: Input/output error
+qemu-img: warning: error while reading offset read_fail_offset_9: Input/output error
+
+wrote 512/512 bytes at offset read_fail_offset_0
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_1
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_2
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_3
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_4
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_5
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_6
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_7
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_8
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset read_fail_offset_9
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+Images are identical.
+*** done
diff --git a/tests/qemu-iotests/254 b/tests/qemu-iotests/254
index 33cb80a512..8edba91c5d 100755
--- a/tests/qemu-iotests/254
+++ b/tests/qemu-iotests/254
@@ -21,6 +21,8 @@
 import iotests
 from iotests import qemu_img_create, file_path, log
 
+iotests.verify_image_format(supported_fmts=['qcow2'])
+
 disk, top = file_path('disk', 'top')
 size = 1024 * 1024
 
diff --git a/tests/qemu-iotests/256 b/tests/qemu-iotests/256
new file mode 100755
index 0000000000..c594a43205
--- /dev/null
+++ b/tests/qemu-iotests/256
@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+#
+# Test incremental/backup across iothread contexts
+#
+# Copyright (c) 2019 John Snow for Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# owner=jsnow@redhat.com
+
+import os
+import iotests
+from iotests import log
+
+iotests.verify_image_format(supported_fmts=['qcow2'])
+size = 64 * 1024 * 1024
+
+with iotests.FilePath('img0') as img0_path, \
+     iotests.FilePath('img1') as img1_path, \
+     iotests.FilePath('img0-full') as img0_full_path, \
+     iotests.FilePath('img1-full') as img1_full_path, \
+     iotests.FilePath('img0-incr') as img0_incr_path, \
+     iotests.FilePath('img1-incr') as img1_incr_path, \
+     iotests.VM() as vm:
+
+    def create_target(filepath, name, size):
+        basename = os.path.basename(filepath)
+        nodename = "file_{}".format(basename)
+        log(vm.command('blockdev-create', job_id='job1',
+                       options={
+                           'driver': 'file',
+                           'filename': filepath,
+                           'size': 0,
+                       }))
+        vm.run_job('job1')
+        log(vm.command('blockdev-add', driver='file',
+                       node_name=nodename, filename=filepath))
+        log(vm.command('blockdev-create', job_id='job2',
+                       options={
+                           'driver': iotests.imgfmt,
+                           'file': nodename,
+                           'size': size,
+                       }))
+        vm.run_job('job2')
+        log(vm.command('blockdev-add', driver=iotests.imgfmt,
+                       node_name=name,
+                       file=nodename))
+
+    log('--- Preparing images & VM ---\n')
+    vm.add_object('iothread,id=iothread0')
+    vm.add_object('iothread,id=iothread1')
+    vm.add_device('virtio-scsi-pci,id=scsi0,iothread=iothread0')
+    vm.add_device('virtio-scsi-pci,id=scsi1,iothread=iothread1')
+    iotests.qemu_img_create('-f', iotests.imgfmt, img0_path, str(size))
+    iotests.qemu_img_create('-f', iotests.imgfmt, img1_path, str(size))
+    vm.add_drive(img0_path, interface='none')
+    vm.add_device('scsi-hd,id=device0,drive=drive0,bus=scsi0.0')
+    vm.add_drive(img1_path, interface='none')
+    vm.add_device('scsi-hd,id=device1,drive=drive1,bus=scsi1.0')
+
+    log('--- Starting VM ---\n')
+    vm.launch()
+
+    log('--- Create Targets & Full Backups ---\n')
+    create_target(img0_full_path, 'img0-full', size)
+    create_target(img1_full_path, 'img1-full', size)
+    ret = vm.qmp_log('transaction', indent=2, actions=[
+        { 'type': 'block-dirty-bitmap-add',
+          'data': { 'node': 'drive0', 'name': 'bitmap0' }},
+        { 'type': 'block-dirty-bitmap-add',
+          'data': { 'node': 'drive1', 'name': 'bitmap1' }},
+        { 'type': 'blockdev-backup',
+          'data': { 'device': 'drive0',
+                    'target': 'img0-full',
+                    'sync': 'full',
+                    'job-id': 'j0' }},
+        { 'type': 'blockdev-backup',
+          'data': { 'device': 'drive1',
+                    'target': 'img1-full',
+                    'sync': 'full',
+                    'job-id': 'j1' }}
+    ])
+    if "error" in ret:
+        raise Exception(ret['error']['desc'])
+    vm.run_job('j0', auto_dismiss=True)
+    vm.run_job('j1', auto_dismiss=True)
+
+    log('\n--- Create Targets & Incremental Backups ---\n')
+    create_target(img0_incr_path, 'img0-incr', size)
+    create_target(img1_incr_path, 'img1-incr', size)
+    ret = vm.qmp_log('transaction', indent=2, actions=[
+        { 'type': 'blockdev-backup',
+          'data': { 'device': 'drive0',
+                    'target': 'img0-incr',
+                    'sync': 'incremental',
+                    'bitmap': 'bitmap0',
+                    'job-id': 'j2' }},
+        { 'type': 'blockdev-backup',
+          'data': { 'device': 'drive1',
+                    'target': 'img1-incr',
+                    'sync': 'incremental',
+                    'bitmap': 'bitmap1',
+                    'job-id': 'j3' }}
+    ])
+    if "error" in ret:
+        raise Exception(ret['error']['desc'])
+    vm.run_job('j2', auto_dismiss=True)
+    vm.run_job('j3', auto_dismiss=True)
+
+    log('\n--- Done ---')
+    vm.shutdown()
diff --git a/tests/qemu-iotests/256.out b/tests/qemu-iotests/256.out
new file mode 100644
index 0000000000..eec38614ec
--- /dev/null
+++ b/tests/qemu-iotests/256.out
@@ -0,0 +1,119 @@
+--- Preparing images & VM ---
+
+--- Starting VM ---
+
+--- Create Targets & Full Backups ---
+
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job1"}}
+{"return": {}}
+{}
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job2"}}
+{"return": {}}
+{}
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job1"}}
+{"return": {}}
+{}
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job2"}}
+{"return": {}}
+{}
+{
+  "execute": "transaction",
+  "arguments": {
+    "actions": [
+      {
+        "data": {
+          "name": "bitmap0",
+          "node": "drive0"
+        },
+        "type": "block-dirty-bitmap-add"
+      },
+      {
+        "data": {
+          "name": "bitmap1",
+          "node": "drive1"
+        },
+        "type": "block-dirty-bitmap-add"
+      },
+      {
+        "data": {
+          "device": "drive0",
+          "job-id": "j0",
+          "sync": "full",
+          "target": "img0-full"
+        },
+        "type": "blockdev-backup"
+      },
+      {
+        "data": {
+          "device": "drive1",
+          "job-id": "j1",
+          "sync": "full",
+          "target": "img1-full"
+        },
+        "type": "blockdev-backup"
+      }
+    ]
+  }
+}
+{
+  "return": {}
+}
+{"data": {"device": "j0", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"device": "j1", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+
+--- Create Targets & Incremental Backups ---
+
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job1"}}
+{"return": {}}
+{}
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job2"}}
+{"return": {}}
+{}
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job1"}}
+{"return": {}}
+{}
+{}
+{"execute": "job-dismiss", "arguments": {"id": "job2"}}
+{"return": {}}
+{}
+{
+  "execute": "transaction",
+  "arguments": {
+    "actions": [
+      {
+        "data": {
+          "bitmap": "bitmap0",
+          "device": "drive0",
+          "job-id": "j2",
+          "sync": "incremental",
+          "target": "img0-incr"
+        },
+        "type": "blockdev-backup"
+      },
+      {
+        "data": {
+          "bitmap": "bitmap1",
+          "device": "drive1",
+          "job-id": "j3",
+          "sync": "incremental",
+          "target": "img1-incr"
+        },
+        "type": "blockdev-backup"
+      }
+    ]
+  }
+}
+{
+  "return": {}
+}
+{"data": {"device": "j2", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"device": "j3", "len": 67108864, "offset": 67108864, "speed": 0, "type": "backup"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+
+--- Done ---
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index f3b6d601b2..b34c8e3c0c 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -263,7 +263,9 @@
 248 rw quick
 249 rw auto quick
 250 rw auto quick
+251 rw auto quick
 252 rw auto backing quick
 253 rw auto quick
 254 rw auto backing quick
 255 rw auto quick
+256 rw auto quick
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index f11482f3dc..3ecef5bc90 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -524,7 +524,7 @@ class VM(qtest.QEMUQtestMachine):
             output_list += [key + '=' + obj[key]]
         return ','.join(output_list)
 
-    def get_qmp_events_filtered(self, wait=True):
+    def get_qmp_events_filtered(self, wait=60.0):
         result = []
         for ev in self.get_qmp_events(wait=wait):
             result.append(filter_qmp_event(ev))
@@ -542,28 +542,38 @@ class VM(qtest.QEMUQtestMachine):
 
     # Returns None on success, and an error string on failure
     def run_job(self, job, auto_finalize=True, auto_dismiss=False,
-                pre_finalize=None):
+                pre_finalize=None, wait=60.0):
+        match_device = {'data': {'device': job}}
+        match_id = {'data': {'id': job}}
+        events = [
+            ('BLOCK_JOB_COMPLETED', match_device),
+            ('BLOCK_JOB_CANCELLED', match_device),
+            ('BLOCK_JOB_ERROR', match_device),
+            ('BLOCK_JOB_READY', match_device),
+            ('BLOCK_JOB_PENDING', match_id),
+            ('JOB_STATUS_CHANGE', match_id)
+        ]
         error = None
         while True:
-            for ev in self.get_qmp_events_filtered(wait=True):
-                if ev['event'] == 'JOB_STATUS_CHANGE':
-                    status = ev['data']['status']
-                    if status == 'aborting':
-                        result = self.qmp('query-jobs')
-                        for j in result['return']:
-                            if j['id'] == job:
-                                error = j['error']
-                                log('Job failed: %s' % (j['error']))
-                    elif status == 'pending' and not auto_finalize:
-                        if pre_finalize:
-                            pre_finalize()
-                        self.qmp_log('job-finalize', id=job)
-                    elif status == 'concluded' and not auto_dismiss:
-                        self.qmp_log('job-dismiss', id=job)
-                    elif status == 'null':
-                        return error
-                else:
-                    log(ev)
+            ev = filter_qmp_event(self.events_wait(events))
+            if ev['event'] != 'JOB_STATUS_CHANGE':
+                log(ev)
+                continue
+            status = ev['data']['status']
+            if status == 'aborting':
+                result = self.qmp('query-jobs')
+                for j in result['return']:
+                    if j['id'] == job:
+                        error = j['error']
+                        log('Job failed: %s' % (j['error']))
+            elif status == 'pending' and not auto_finalize:
+                if pre_finalize:
+                    pre_finalize()
+                self.qmp_log('job-finalize', id=job)
+            elif status == 'concluded' and not auto_dismiss:
+                self.qmp_log('job-dismiss', id=job)
+            elif status == 'null':
+                return error
 
     def node_info(self, node_name):
         nodes = self.qmp('query-named-block-nodes')
@@ -650,7 +660,7 @@ class QMPTestCase(unittest.TestCase):
         self.assertEqual(self.vm.flatten_qmp_object(json.loads(json_filename[5:])),
                          self.vm.flatten_qmp_object(reference))
 
-    def cancel_and_wait(self, drive='drive0', force=False, resume=False):
+    def cancel_and_wait(self, drive='drive0', force=False, resume=False, wait=60.0):
         '''Cancel a block job and wait for it to finish, returning the event'''
         result = self.vm.qmp('block-job-cancel', device=drive, force=force)
         self.assert_qmp(result, 'return', {})
@@ -661,7 +671,7 @@ class QMPTestCase(unittest.TestCase):
         cancelled = False
         result = None
         while not cancelled:
-            for event in self.vm.get_qmp_events(wait=True):
+            for event in self.vm.get_qmp_events(wait=wait):
                 if event['event'] == 'BLOCK_JOB_COMPLETED' or \
                    event['event'] == 'BLOCK_JOB_CANCELLED':
                     self.assert_qmp(event, 'data/device', drive)
@@ -674,10 +684,10 @@ class QMPTestCase(unittest.TestCase):
         self.assert_no_active_block_jobs()
         return result
 
-    def wait_until_completed(self, drive='drive0', check_offset=True):
+    def wait_until_completed(self, drive='drive0', check_offset=True, wait=60.0):
         '''Wait for a block job to finish, returning the event'''
         while True:
-            for event in self.vm.get_qmp_events(wait=True):
+            for event in self.vm.get_qmp_events(wait=wait):
                 if event['event'] == 'BLOCK_JOB_COMPLETED':
                     self.assert_qmp(event, 'data/device', drive)
                     self.assert_qmp_absent(event, 'data/error')