Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2017-04-03' into staging

Block patches for 2.9-rc3

# gpg: Signature made Mon 03 Apr 2017 16:29:49 BST
# gpg:                using RSA key 0xF407DB0061D5CF40
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>"
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/maxreitz/tags/pull-block-2017-04-03:
  block/parallels: Avoid overflows
  iotests: Improve image-clear tests on non-aligned image
  qcow2: Discard unaligned tail when wiping image
  iotests: fix 097 when run with qcow
  qemu-io-cmds: Assert that global and nofile commands don't use ct->perms
  sheepdog: Fix blockdev-add
  nbd: Tidy up blockdev-add interface
  sockets: New helper socket_address_crumple()
  qapi-schema: SocketAddressFlat variants 'vsock' and 'fd'
  gluster: Prepare for SocketAddressFlat extension
  block: Document -drive problematic code and bugs
  io vnc sockets: Clean up SocketAddressKind switches
  char: Fix socket with "type": "vsock" address
  nbd sockets vnc: Mark problematic address family tests TODO
  block: add missed aio_context_acquire into release_drive

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

6 files changed, 358 insertions, 156 deletions

diff --git a/tests/qemu-iotests/097 b/tests/qemu-iotests/097
index 4c33e8038a..e22670c8d0 100755
--- a/tests/qemu-iotests/097
+++ b/tests/qemu-iotests/097
@@ -56,30 +56,25 @@ _supported_os Linux
 #  3: Two-layer backing chain, commit to lower backing file
 #     (in this case, the top image will implicitly stay unchanged)
 #
-# Each pass is run twice, since qcow2 has different code paths for cleaning
-# an image depending on whether it has a snapshot.
-#
 # 020 already tests committing, so this only tests whether image chains are
 # working properly and that all images above the base are emptied; therefore,
 # no complicated patterns are necessary.  Check near the 2G mark, as qcow2
 # has been buggy at that boundary in the past.
 for i in 0 1 2 3; do
-for j in 0 1; do
 
 echo
-echo "=== Test pass $i.$j ==="
+echo "=== Test pass $i ==="
 echo
 
-TEST_IMG="$TEST_IMG.base" _make_test_img 2100M
-TEST_IMG="$TEST_IMG.itmd" _make_test_img -b "$TEST_IMG.base" 2100M
-_make_test_img -b "$TEST_IMG.itmd" 2100M
-if [ $j -eq 0 ]; then
-    $QEMU_IMG snapshot -c snap "$TEST_IMG"
-fi
+len=$((2100 * 1024 * 1024 + 512)) # larger than 2G, and not cluster aligned
+TEST_IMG="$TEST_IMG.base" _make_test_img $len
+TEST_IMG="$TEST_IMG.itmd" _make_test_img -b "$TEST_IMG.base" $len
+_make_test_img -b "$TEST_IMG.itmd" $len
 
-$QEMU_IO -c 'write -P 1 0x7ffd0000 192k' "$TEST_IMG.base" | _filter_qemu_io
-$QEMU_IO -c 'write -P 2 0x7ffe0000 128k' "$TEST_IMG.itmd" | _filter_qemu_io
-$QEMU_IO -c 'write -P 3 0x7fff0000 64k' "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "write -P 1 0x7ffd0000 192k" "$TEST_IMG.base" | _filter_qemu_io
+$QEMU_IO -c "write -P 2 0x7ffe0000 128k" "$TEST_IMG.itmd" | _filter_qemu_io
+$QEMU_IO -c "write -P 3 0x7fff0000 64k" "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "write -P 4 $(($len - 512)) 512" "$TEST_IMG" | _filter_qemu_io
 
 if [ $i -lt 3 ]; then
     if [ $i == 0 ]; then
@@ -97,11 +92,13 @@ if [ $i -lt 3 ]; then
 
     # Bottom should be unchanged
     $QEMU_IO -c 'read -P 1 0x7ffd0000 192k' "$TEST_IMG.base" | _filter_qemu_io
+    $QEMU_IO -c "read -P 0 $((len - 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
 
     # Intermediate should contain changes from top
     $QEMU_IO -c 'read -P 1 0x7ffd0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
     $QEMU_IO -c 'read -P 2 0x7ffe0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
     $QEMU_IO -c 'read -P 3 0x7fff0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
+    $QEMU_IO -c "read -P 4 $((len - 512)) 512" "$TEST_IMG.itmd" | _filter_qemu_io
 
     # And in pass 0, the top image should be empty, whereas in both other passes
     # it should be unchanged (which is both checked by qemu-img map)
@@ -112,6 +109,7 @@ else
     $QEMU_IO -c 'read -P 1 0x7ffd0000 64k' "$TEST_IMG.base" | _filter_qemu_io
     $QEMU_IO -c 'read -P 2 0x7ffe0000 64k' "$TEST_IMG.base" | _filter_qemu_io
     $QEMU_IO -c 'read -P 3 0x7fff0000 64k' "$TEST_IMG.base" | _filter_qemu_io
+    $QEMU_IO -c "read -P 4 $((len - 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
 
     # Both top and intermediate should be unchanged
 fi
@@ -121,7 +119,6 @@ $QEMU_IMG map "$TEST_IMG.itmd" | _filter_qemu_img_map
 $QEMU_IMG map "$TEST_IMG" | _filter_qemu_img_map
 
 done
-done
 
 
 # success, all done
diff --git a/tests/qemu-iotests/097.out b/tests/qemu-iotests/097.out
index 8106cc9275..f6705a1cc7 100644
--- a/tests/qemu-iotests/097.out
+++ b/tests/qemu-iotests/097.out
@@ -1,222 +1,131 @@
 QA output created by 097
 
-=== Test pass 0.0 ===
+=== Test pass 0 ===
 
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
 wrote 196608/196608 bytes at offset 2147287040
 192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 131072/131072 bytes at offset 2147352576
 128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Image committed.
 read 196608/196608 bytes at offset 2147287040
 192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147287040
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147352576
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Offset          Length          File
 0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
 
-=== Test pass 0.1 ===
+=== Test pass 1 ===
 
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
-wrote 196608/196608 bytes at offset 2147287040
-192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 131072/131072 bytes at offset 2147352576
-128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Image committed.
-read 196608/196608 bytes at offset 2147287040
-192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147287040
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147352576
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Offset          Length          File
-0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
-
-=== Test pass 1.0 ===
-
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
-wrote 196608/196608 bytes at offset 2147287040
-192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 131072/131072 bytes at offset 2147352576
-128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Image committed.
-read 196608/196608 bytes at offset 2147287040
-192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147287040
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147352576
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Offset          Length          File
-0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
-0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
-
-=== Test pass 1.1 ===
-
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
 wrote 196608/196608 bytes at offset 2147287040
 192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 131072/131072 bytes at offset 2147352576
 128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Image committed.
 read 196608/196608 bytes at offset 2147287040
 192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147287040
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147352576
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Offset          Length          File
 0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
 0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
+0x83400000      0x200           TEST_DIR/t.IMGFMT
 
-=== Test pass 2.0 ===
+=== Test pass 2 ===
 
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
 wrote 196608/196608 bytes at offset 2147287040
 192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 131072/131072 bytes at offset 2147352576
 128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Image committed.
 read 196608/196608 bytes at offset 2147287040
 192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147287040
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147352576
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Offset          Length          File
 0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
 0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
+0x83400000      0x200           TEST_DIR/t.IMGFMT
 
-=== Test pass 2.1 ===
-
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
-wrote 196608/196608 bytes at offset 2147287040
-192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 131072/131072 bytes at offset 2147352576
-128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Image committed.
-read 196608/196608 bytes at offset 2147287040
-192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147287040
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147352576
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Offset          Length          File
-0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
-0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
-
-=== Test pass 3.0 ===
-
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
-wrote 196608/196608 bytes at offset 2147287040
-192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 131072/131072 bytes at offset 2147352576
-128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-wrote 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Image committed.
-read 65536/65536 bytes at offset 2147287040
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147352576
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65536/65536 bytes at offset 2147418112
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-Offset          Length          File
-0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
-Offset          Length          File
-0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
-0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
-0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
-
-=== Test pass 3.1 ===
+=== Test pass 3 ===
 
-Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202009600
-Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.base
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202009600 backing_file=TEST_DIR/t.IMGFMT.itmd
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
 wrote 196608/196608 bytes at offset 2147287040
 192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 131072/131072 bytes at offset 2147352576
 128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Image committed.
 read 65536/65536 bytes at offset 2147287040
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
@@ -224,13 +133,18 @@ read 65536/65536 bytes at offset 2147352576
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 65536/65536 bytes at offset 2147418112
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Offset          Length          File
 0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
+0x83400000      0x200           TEST_DIR/t.IMGFMT.base
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.base
 Offset          Length          File
 0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
 0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
 0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
+0x83400000      0x200           TEST_DIR/t.IMGFMT
 *** done
diff --git a/tests/qemu-iotests/147 b/tests/qemu-iotests/147
index cca75c562c..32afea63d4 100755
--- a/tests/qemu-iotests/147
+++ b/tests/qemu-iotests/147
@@ -30,6 +30,13 @@ NBD_PORT = 10811
 test_img = os.path.join(iotests.test_dir, 'test.img')
 unix_socket = os.path.join(iotests.test_dir, 'nbd.socket')
 
+
+def flatten_sock_addr(crumpled_address):
+    result = { 'type': crumpled_address['type'] }
+    result.update(crumpled_address['data'])
+    return result
+
+
 class NBDBlockdevAddBase(iotests.QMPTestCase):
     def blockdev_add_options(self, address, export=None):
         options = { 'node-name': 'nbd-blockdev',
@@ -85,13 +92,15 @@ class QemuNBD(NBDBlockdevAddBase):
                         'host': 'localhost',
                         'port': str(NBD_PORT)
                     } }
-        self.client_test('nbd://localhost:%i' % NBD_PORT, address)
+        self.client_test('nbd://localhost:%i' % NBD_PORT,
+                         flatten_sock_addr(address))
 
     def test_unix(self):
         self._server_up('-k', unix_socket)
         address = { 'type': 'unix',
                     'data': { 'path': unix_socket } }
-        self.client_test('nbd+unix://?socket=' + unix_socket, address)
+        self.client_test('nbd+unix://?socket=' + unix_socket,
+                         flatten_sock_addr(address))
 
 
 class BuiltinNBD(NBDBlockdevAddBase):
@@ -134,7 +143,7 @@ class BuiltinNBD(NBDBlockdevAddBase):
                     } }
         self._server_up(address)
         self.client_test('nbd://localhost:%i/nbd-export' % NBD_PORT,
-                         address, 'nbd-export')
+                         flatten_sock_addr(address), 'nbd-export')
         self._server_down()
 
     def test_inet6(self):
@@ -149,10 +158,10 @@ class BuiltinNBD(NBDBlockdevAddBase):
                      'file': {
                          'driver': 'nbd',
                          'export': 'nbd-export',
-                         'server': address
+                         'server': flatten_sock_addr(address)
                      } }
         self._server_up(address)
-        self.client_test(filename, address, 'nbd-export')
+        self.client_test(filename, flatten_sock_addr(address), 'nbd-export')
         self._server_down()
 
     def test_unix(self):
@@ -160,7 +169,7 @@ class BuiltinNBD(NBDBlockdevAddBase):
                     'data': { 'path': unix_socket } }
         self._server_up(address)
         self.client_test('nbd+unix:///nbd-export?socket=' + unix_socket,
-                         address, 'nbd-export')
+                         flatten_sock_addr(address), 'nbd-export')
         self._server_down()
 
     def test_fd(self):
@@ -182,9 +191,9 @@ class BuiltinNBD(NBDBlockdevAddBase):
                      'file': {
                          'driver': 'nbd',
                          'export': 'nbd-export',
-                         'server': address
+                         'server': flatten_sock_addr(address)
                      } }
-        self.client_test(filename, address, 'nbd-export')
+        self.client_test(filename, flatten_sock_addr(address), 'nbd-export')
 
         self._server_down()
 
diff --git a/tests/qemu-iotests/176 b/tests/qemu-iotests/176
new file mode 100755
index 0000000000..950b28720e
--- /dev/null
+++ b/tests/qemu-iotests/176
@@ -0,0 +1,131 @@
+#!/bin/bash
+#
+# Commit changes into backing chains and empty the top image if the
+# backing image is not explicitly specified.
+#
+# Variant of 097, which includes snapshots to test different codepath
+# in qcow2
+#
+# Copyright (C) 2014 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 $seq"
+
+here="$PWD"
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+    _rm_test_img "$TEST_IMG.itmd"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.pattern
+
+# Any format supporting backing files and bdrv_make_empty
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+
+# Four passes:
+#  0: Two-layer backing chain, commit to upper backing file (implicitly)
+#     (in this case, the top image will be emptied)
+#  1: Two-layer backing chain, commit to upper backing file (explicitly)
+#     (in this case, the top image will implicitly stay unchanged)
+#  2: Two-layer backing chain, commit to upper backing file (implicitly with -d)
+#     (in this case, the top image will explicitly stay unchanged)
+#  3: Two-layer backing chain, commit to lower backing file
+#     (in this case, the top image will implicitly stay unchanged)
+#
+# 020 already tests committing, so this only tests whether image chains are
+# working properly and that all images above the base are emptied; therefore,
+# no complicated patterns are necessary.  Check near the 2G mark, as qcow2
+# has been buggy at that boundary in the past.
+for i in 0 1 2 3; do
+
+echo
+echo "=== Test pass $i ==="
+echo
+
+len=$((2100 * 1024 * 1024 + 512)) # larger than 2G, and not cluster aligned
+TEST_IMG="$TEST_IMG.base" _make_test_img $len
+TEST_IMG="$TEST_IMG.itmd" _make_test_img -b "$TEST_IMG.base" $len
+_make_test_img -b "$TEST_IMG.itmd" $len
+$QEMU_IMG snapshot -c snap "$TEST_IMG"
+
+$QEMU_IO -c "write -P 1 0x7ffd0000 192k" "$TEST_IMG.base" | _filter_qemu_io
+$QEMU_IO -c "write -P 2 0x7ffe0000 128k" "$TEST_IMG.itmd" | _filter_qemu_io
+$QEMU_IO -c "write -P 3 0x7fff0000 64k" "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "write -P 4 $(($len - 512)) 512" "$TEST_IMG" | _filter_qemu_io
+
+if [ $i -lt 3 ]; then
+    if [ $i == 0 ]; then
+        # -b "$TEST_IMG.itmd" should be the default (that is, committing to the
+        # first backing file in the chain)
+        $QEMU_IMG commit "$TEST_IMG"
+    elif [ $i == 1 ]; then
+        # explicitly specify the commit target (this should imply -d)
+        $QEMU_IMG commit -b "$TEST_IMG.itmd" "$TEST_IMG"
+    else
+        # do not explicitly specify the commit target, but use -d to leave the
+        # top image unchanged
+        $QEMU_IMG commit -d "$TEST_IMG"
+    fi
+
+    # Bottom should be unchanged
+    $QEMU_IO -c 'read -P 1 0x7ffd0000 192k' "$TEST_IMG.base" | _filter_qemu_io
+    $QEMU_IO -c "read -P 0 $((len - 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
+
+    # Intermediate should contain changes from top
+    $QEMU_IO -c 'read -P 1 0x7ffd0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
+    $QEMU_IO -c 'read -P 2 0x7ffe0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
+    $QEMU_IO -c 'read -P 3 0x7fff0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
+    $QEMU_IO -c "read -P 4 $((len - 512)) 512" "$TEST_IMG.itmd" | _filter_qemu_io
+
+    # And in pass 0, the top image should be empty, whereas in both other passes
+    # it should be unchanged (which is both checked by qemu-img map)
+else
+    $QEMU_IMG commit -b "$TEST_IMG.base" "$TEST_IMG"
+
+    # Bottom should contain all changes
+    $QEMU_IO -c 'read -P 1 0x7ffd0000 64k' "$TEST_IMG.base" | _filter_qemu_io
+    $QEMU_IO -c 'read -P 2 0x7ffe0000 64k' "$TEST_IMG.base" | _filter_qemu_io
+    $QEMU_IO -c 'read -P 3 0x7fff0000 64k' "$TEST_IMG.base" | _filter_qemu_io
+    $QEMU_IO -c "read -P 4 $((len - 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
+
+    # Both top and intermediate should be unchanged
+fi
+
+$QEMU_IMG map "$TEST_IMG.base" | _filter_qemu_img_map
+$QEMU_IMG map "$TEST_IMG.itmd" | _filter_qemu_img_map
+$QEMU_IMG map "$TEST_IMG" | _filter_qemu_img_map
+
+done
+
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/176.out b/tests/qemu-iotests/176.out
new file mode 100644
index 0000000000..6271fa7d6f
--- /dev/null
+++ b/tests/qemu-iotests/176.out
@@ -0,0 +1,150 @@
+QA output created by 176
+
+=== Test pass 0 ===
+
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
+wrote 196608/196608 bytes at offset 2147287040
+192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 131072/131072 bytes at offset 2147352576
+128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Image committed.
+read 196608/196608 bytes at offset 2147287040
+192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147287040
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147352576
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Offset          Length          File
+0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
+
+=== Test pass 1 ===
+
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
+wrote 196608/196608 bytes at offset 2147287040
+192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 131072/131072 bytes at offset 2147352576
+128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Image committed.
+read 196608/196608 bytes at offset 2147287040
+192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147287040
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147352576
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Offset          Length          File
+0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
+0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
+0x83400000      0x200           TEST_DIR/t.IMGFMT
+
+=== Test pass 2 ===
+
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
+wrote 196608/196608 bytes at offset 2147287040
+192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 131072/131072 bytes at offset 2147352576
+128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Image committed.
+read 196608/196608 bytes at offset 2147287040
+192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147287040
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147352576
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Offset          Length          File
+0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
+0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
+0x83400000      0x200           TEST_DIR/t.IMGFMT
+
+=== Test pass 3 ===
+
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=2202010112
+Formatting 'TEST_DIR/t.IMGFMT.itmd', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2202010112 backing_file=TEST_DIR/t.IMGFMT.itmd
+wrote 196608/196608 bytes at offset 2147287040
+192 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 131072/131072 bytes at offset 2147352576
+128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Image committed.
+read 65536/65536 bytes at offset 2147287040
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147352576
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 2147418112
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 512/512 bytes at offset 2202009600
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Offset          Length          File
+0x7ffd0000      0x30000         TEST_DIR/t.IMGFMT.base
+0x83400000      0x200           TEST_DIR/t.IMGFMT.base
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
+0x83400000      0x200           TEST_DIR/t.IMGFMT.base
+Offset          Length          File
+0x7ffd0000      0x10000         TEST_DIR/t.IMGFMT.base
+0x7ffe0000      0x10000         TEST_DIR/t.IMGFMT.itmd
+0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
+0x83400000      0x200           TEST_DIR/t.IMGFMT
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 1f4bf03185..43142ddfcf 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -168,3 +168,4 @@
 173 rw auto
 174 auto
 175 auto quick
+176 rw auto backing