qcow2: fix image corruption on commit with persistent bitmap
If an image contains persistent bitmaps, we cannot use the
fast path of bdrv_make_empty() to clear the image during
qemu-img commit, because that will lose the clusters related
to the bitmaps.
Also leave a comment in qcow2_read_extensions to remind future
feature additions to think about fast-path removal, since we
just barely fixed the same bug for LUKS encryption.
It's a pain that qemu-img has not yet been taught to manipulate,
or even at a very minimum display, information about persistent
bitmaps; instead, we have to use QMP commands. It's also a
pain that only qeury-block and x-debug-block-dirty-bitmap-sha256
will allow bitmap introspection; but the former requires the
node to be hooked to a block device, and the latter is experimental.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index e9a86b7..f2731a7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -376,6 +376,8 @@
default:
/* unknown magic - save it in case we need to rewrite the header */
+ /* If you add a new feature, make sure to also update the fast
+ * path of qcow2_make_empty() to deal with it. */
{
Qcow2UnknownHeaderExtension *uext;
@@ -3600,15 +3602,16 @@
l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
- if (s->qcow_version >= 3 && !s->snapshots &&
+ if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps &&
3 + l1_clusters <= s->refcount_block_size &&
s->crypt_method_header != QCOW_CRYPT_LUKS) {
- /* The following function only works for qcow2 v3 images (it requires
- * the dirty flag) and only as long as there are no snapshots (because
- * it completely empties the image). Furthermore, the L1 table and three
- * additional clusters (image header, refcount table, one refcount
- * block) have to fit inside one refcount block. It cannot be used
- * for LUKS (yet) as it throws away the LUKS header cluster(s) */
+ /* The following function only works for qcow2 v3 images (it
+ * requires the dirty flag) and only as long as there are no
+ * features that reserve extra clusters (such as snapshots,
+ * LUKS header, or persistent bitmaps), because it completely
+ * empties the image. Furthermore, the L1 table and three
+ * additional clusters (image header, refcount table, one
+ * refcount block) have to fit inside one refcount block. */
return make_completely_empty(bs);
}
diff --git a/tests/qemu-iotests/176 b/tests/qemu-iotests/176
index 950b287..0f31a20 100755
--- a/tests/qemu-iotests/176
+++ b/tests/qemu-iotests/176
@@ -3,10 +3,11 @@
# 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
+# Variant of 097, which includes snapshots and persistent bitmaps, to
+# tickle the slow codepath in qcow2. See also 198, for another feature
+# that tickles the slow codepath.
#
-# Copyright (C) 2014 Red Hat, Inc.
+# Copyright (C) 2014, 2017 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
@@ -43,11 +44,18 @@
. ./common.filter
. ./common.pattern
-# Any format supporting backing files and bdrv_make_empty
+# This test is specific to qcow2
_supported_fmt qcow2
_supported_proto file
_supported_os Linux
+function run_qemu()
+{
+ $QEMU -nographic -qmp stdio -serial none "$@" 2>&1 \
+ | _filter_testdir | _filter_qmp | _filter_qemu
+}
+
+for reason in snapshot bitmap; do
# Four passes:
# 0: Two-layer backing chain, commit to upper backing file (implicitly)
@@ -66,14 +74,29 @@
for i in 0 1 2 3; do
echo
-echo "=== Test pass $i ==="
+echo "=== Test pass $reason.$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"
+# Update the top image to use a feature that is incompatible with fast path
+case $reason in
+ snapshot) $QEMU_IMG snapshot -c snap "$TEST_IMG" ;;
+ bitmap)
+ run_qemu <<EOF
+{ "execute": "qmp_capabilities" }
+{ "execute": "blockdev-add",
+ "arguments": { "driver": "qcow2", "node-name": "drive0",
+ "file": { "driver": "file", "filename": "$TEST_IMG" } } }
+{ "execute": "block-dirty-bitmap-add",
+ "arguments": { "node": "drive0", "name": "bitmap0",
+ "persistent": true, "autoload": true } }
+{ "execute": "quit" }
+EOF
+ ;;
+esac
$QEMU_IO -c "write -P 1 0x7ffd0000 192k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -P 2 0x7ffe0000 128k" "$TEST_IMG.itmd" | _filter_qemu_io
@@ -122,8 +145,26 @@
$QEMU_IMG map "$TEST_IMG.itmd" | _filter_qemu_img_map
$QEMU_IMG map "$TEST_IMG" | _filter_qemu_img_map
-done
+# Check that the reason for slow path is still present, as appropriate
+case $reason in
+ snapshot)
+ $QEMU_IMG snapshot -l "$TEST_IMG" |
+ sed 's/^\(.\{20\}\).*/\1/; s/ *$//' ;;
+ bitmap)
+ run_qemu <<EOF
+{ "execute": "qmp_capabilities" }
+{ "execute": "blockdev-add",
+ "arguments": { "driver": "qcow2", "node-name": "drive0",
+ "file": { "driver": "file", "filename": "$TEST_IMG" } } }
+{ "execute": "x-debug-block-dirty-bitmap-sha256",
+ "arguments": { "node": "drive0", "name": "bitmap0" } }
+{ "execute": "quit" }
+EOF
+ ;;
+esac
+done
+done
# success, all done
echo "*** done"
diff --git a/tests/qemu-iotests/176.out b/tests/qemu-iotests/176.out
index 6271fa7..e62085c 100644
--- a/tests/qemu-iotests/176.out
+++ b/tests/qemu-iotests/176.out
@@ -1,6 +1,6 @@
QA output created by 176
-=== Test pass 0 ===
+=== Test pass snapshot.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
@@ -36,8 +36,11 @@
0x7ffd0000 0x10000 TEST_DIR/t.IMGFMT.base
0x7ffe0000 0x20000 TEST_DIR/t.IMGFMT.itmd
0x83400000 0x200 TEST_DIR/t.IMGFMT.itmd
+Snapshot list:
+ID TAG
+1 snap
-=== Test pass 1 ===
+=== Test pass snapshot.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
@@ -74,8 +77,11 @@
0x7ffe0000 0x10000 TEST_DIR/t.IMGFMT.itmd
0x7fff0000 0x10000 TEST_DIR/t.IMGFMT
0x83400000 0x200 TEST_DIR/t.IMGFMT
+Snapshot list:
+ID TAG
+1 snap
-=== Test pass 2 ===
+=== Test pass snapshot.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
@@ -112,8 +118,11 @@
0x7ffe0000 0x10000 TEST_DIR/t.IMGFMT.itmd
0x7fff0000 0x10000 TEST_DIR/t.IMGFMT
0x83400000 0x200 TEST_DIR/t.IMGFMT
+Snapshot list:
+ID TAG
+1 snap
-=== Test pass 3 ===
+=== Test pass snapshot.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
@@ -147,4 +156,203 @@
0x7ffe0000 0x10000 TEST_DIR/t.IMGFMT.itmd
0x7fff0000 0x10000 TEST_DIR/t.IMGFMT
0x83400000 0x200 TEST_DIR/t.IMGFMT
+Snapshot list:
+ID TAG
+1 snap
+
+=== Test pass bitmap.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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {"sha256": "e12600978d86b5a453861ae5c17d275204673fef3874b7c3c5433c6153d84706"}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+
+=== Test pass bitmap.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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {"sha256": "e12600978d86b5a453861ae5c17d275204673fef3874b7c3c5433c6153d84706"}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+
+=== Test pass bitmap.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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {"sha256": "e12600978d86b5a453861ae5c17d275204673fef3874b7c3c5433c6153d84706"}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+
+=== Test pass bitmap.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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+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
+QMP_VERSION
+{"return": {}}
+{"return": {}}
+{"return": {"sha256": "e12600978d86b5a453861ae5c17d275204673fef3874b7c3c5433c6153d84706"}}
+{"return": {}}
+{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
*** done
