Usage:
-drive file=xxx,id=Y, \
-drive
file=xxxx,id=X,backing_reference.drive_id=Y,backing_reference.hidden-disk.*
It will create such backing chain:
{virtio-blk dev 'Y'}
{virtio-blk dev 'X'}
|
|
|
|
v
v
[base] <- [mid] <- ( Y ) <----------------- (hidden target)
<--------------- ( X )
v ^
v ^
v ^
v ^
>>>> drive-backup sync=none >>>>
X's backing file is hidden-disk, and hidden-disk's backing file is Y.
Disk Y may be opened or reopened in read-write mode, so A block backup
job is automatically created: source is Y and target is hidden-disk.
Signed-off-by: Wen Congyang <we...@cn.fujitsu.com>
Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com>
Signed-off-by: Gonglei <arei.gong...@huawei.com>
---
block.c | 145 ++++++++++++++++++++++++++++++++++++++++++++-
include/block/block.h | 1 +
include/block/block_int.h | 1 +
tests/qemu-iotests/051 | 13 ++++
tests/qemu-iotests/051.out | 13 ++++
5 files changed, 170 insertions(+), 3 deletions(-)
diff --git a/block.c b/block.c
index b4d629e..bd7fa9c 100644
--- a/block.c
+++ b/block.c
@@ -1351,6 +1351,113 @@ free_exit:
return ret;
}
+static void backing_reference_completed(void *opaque, int ret)
+{
+ BlockDriverState *hidden_disk = opaque;
+
+ assert(!hidden_disk->backing_reference);
+}
+
+static int bdrv_open_backing_reference_file(BlockDriverState *bs,
+ QDict *options, Error **errp)
+{
+ const char *backing_name;
+ QDict *hidden_disk_options = NULL;
+ BlockDriverState *backing_hd, *hidden_disk;
+ BlockBackend *backing_blk;
+ Error *local_err = NULL;
+ int ret = 0;
+
+ backing_name = qdict_get_try_str(options, "drive_id");
+ if (!backing_name) {
+ error_setg(errp, "Backing reference needs option drive_id");
+ ret = -EINVAL;
+ goto free_exit;
+ }
+ qdict_del(options, "drive_id");
+
+ qdict_extract_subqdict(options, &hidden_disk_options, "hidden-disk.");
+ if (!qdict_size(hidden_disk_options)) {
+ error_setg(errp, "Backing reference needs option hidden-disk.*");
+ ret = -EINVAL;
+ goto free_exit;
+ }
+
+ if (qdict_size(options)) {
+ const QDictEntry *entry = qdict_first(options);
+ error_setg(errp, "Backing reference used by '%s' doesn't support "
+ "the option '%s'", bdrv_get_device_name(bs), entry->key);
+ ret = -EINVAL;
+ goto free_exit;
+ }
+
+ backing_blk = blk_by_name(backing_name);
+ if (!backing_blk) {
+ error_set(errp, QERR_DEVICE_NOT_FOUND, backing_name);
+ ret = -ENOENT;
+ goto free_exit;
+ }
+
+ backing_hd = blk_bs(backing_blk);
+ /* Backing reference itself? */
+ if (backing_hd == bs || bdrv_find_overlay(backing_hd, bs)) {
+ error_setg(errp, "Backing reference itself");
+ ret = -EINVAL;
+ goto free_exit;
+ }
+
+ if (bdrv_op_is_blocked(backing_hd, BLOCK_OP_TYPE_BACKING_REFERENCE,
+ errp)) {
+ ret = -EBUSY;
+ goto free_exit;
+ }
+
+ /* hidden-disk is bs's backing file */
+ ret = bdrv_open_backing_file(bs, hidden_disk_options, errp);
+ hidden_disk_options = NULL;
+ if (ret < 0) {
+ goto free_exit;
+ }
+
+ hidden_disk = bs->backing_hd;
+ if (!hidden_disk->drv || !hidden_disk->drv->supports_backing) {
+ ret = -EINVAL;
+ error_setg(errp, "Hidden disk's driver doesn't support backing files");
+ goto free_exit;
+ }
+
+ bdrv_set_backing_hd(hidden_disk, backing_hd);
+ bdrv_ref(backing_hd);
+
+ /*
+ * backing hd may be opened or reopened in read-write mode, so we
+ * should backup backing hd to hidden disk
+ */
+ bdrv_op_unblock(hidden_disk, BLOCK_OP_TYPE_BACKUP_TARGET,
+ bs->backing_blocker);
+ bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
+ hidden_disk->backing_blocker);
+
+ bdrv_ref(hidden_disk);
+ backup_start(backing_hd, hidden_disk, 0, MIRROR_SYNC_MODE_NONE,
+ BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT,
+ backing_reference_completed, hidden_disk, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ bdrv_unref(hidden_disk);
+ /* FIXME, use which errno? */
+ ret = -EIO;
+ goto free_exit;
+ }
+
+ bs->backing_reference = true;
+
+free_exit:
+ QDECREF(hidden_disk_options);
+ QDECREF(options);
+ return ret;
+}
+
/*
* Opens a disk image whose options are given as BlockdevRef in another block
* device's options.
@@ -1604,13 +1711,37 @@ int bdrv_open(BlockDriverState **pbs, const char
*filename,
/* If there is a backing file, use it */
if ((flags & BDRV_O_NO_BACKING) == 0) {
- QDict *backing_options;
+ QDict *backing_options, *backing_reference_options;
+ qdict_extract_subqdict(options, &backing_reference_options,
+ "backing_reference.");
qdict_extract_subqdict(options, &backing_options, "backing.");
- ret = bdrv_open_backing_file(bs, backing_options, &local_err);
- if (ret < 0) {
+
+ if (qdict_size(backing_reference_options) &&
+ qdict_size(backing_options)) {
+ error_setg(&local_err,
+ "Option \"backing_reference.*\" and \"backing.*\""
+ " cannot be used together");
+ ret = -EINVAL;
+ QDECREF(backing_reference_options);
+ QDECREF(backing_options);
goto close_and_fail;
}
+ if (qdict_size(backing_reference_options)) {
+ QDECREF(backing_options);
+ ret = bdrv_open_backing_reference_file(bs,
+ backing_reference_options,
+ &local_err);
+ if (ret) {
+ goto close_and_fail;
+ }
+ } else {
+ QDECREF(backing_reference_options);
+ ret = bdrv_open_backing_file(bs, backing_options, &local_err);
+ if (ret < 0) {
+ goto close_and_fail;
+ }
+ }
}
bdrv_refresh_filename(bs);
@@ -1941,6 +2072,14 @@ void bdrv_close(BlockDriverState *bs)
if (bs->drv) {
if (bs->backing_hd) {
BlockDriverState *backing_hd = bs->backing_hd;
+ if (bs->backing_reference) {
+ assert(backing_hd->backing_hd);
+ if (backing_hd->backing_hd->job) {
+ block_job_cancel(backing_hd->backing_hd->job);
+ }
+ bdrv_set_backing_hd(backing_hd, NULL);
+ bdrv_unref(backing_hd->backing_hd);
+ }
bdrv_set_backing_hd(bs, NULL);
bdrv_unref(backing_hd);
}
diff --git a/include/block/block.h b/include/block/block.h
index 68f3b1a..7138e90 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -159,6 +159,7 @@ typedef enum BlockOpType {
BLOCK_OP_TYPE_RESIZE,
BLOCK_OP_TYPE_STREAM,
BLOCK_OP_TYPE_REPLACE,
+ BLOCK_OP_TYPE_BACKING_REFERENCE,
BLOCK_OP_TYPE_MAX,
} BlockOpType;
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 08dd8ba..624945d 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -375,6 +375,7 @@ struct BlockDriverState {
QDict *full_open_options;
char exact_filename[PATH_MAX];
+ bool backing_reference;
BlockDriverState *backing_hd;
BlockDriverState *file;
diff --git a/tests/qemu-iotests/051 b/tests/qemu-iotests/051
index 0360f37..fd67f40 100755
--- a/tests/qemu-iotests/051
+++ b/tests/qemu-iotests/051
@@ -116,6 +116,19 @@ run_qemu -drive
file="$TEST_IMG",file.backing.driver=file,file.backing.filename=
run_qemu -drive
file="$TEST_IMG",file.backing.driver=qcow2,file.backing.file.filename="$TEST_IMG.orig"
echo
+echo === Backing file reference ===
+echo
+
+run_qemu -drive file="$TEST_IMG",if=none,id=drive0 \
+ -drive
file="$TEST_IMG",driver=qcow2,backing_reference.drive_id=drive0,backing_reference.hidden-disk.filename="$TEST_IMG.hidden"
+
+run_qemu -drive file="$TEST_IMG",if=none,id=drive0 \
+ -drive
file="$TEST_IMG",driver=qcow2,backing_reference.drive_id=drive0,backing_reference.hidden-disk.filename="$TEST_IMG.hidden",backing.file.filename="$TEST_IMG.orig"
+
+run_qemu -drive file="$TEST_IMG",if=none,id=drive0 \
+ -drive
file="$TEST_IMG",driver=qcow2,file.backing_reference.drive_id=drive0,file.backing_reference.hidden-disk.filename="$TEST_IMG.hidden",file.backing.file.filename="$TEST_IMG.orig"
+
+echo
echo === Enable and disable lazy refcounting on the command line, plus some
invalid values ===
echo
diff --git a/tests/qemu-iotests/051.out b/tests/qemu-iotests/051.out
index 2890eac..cb8340b 100644
--- a/tests/qemu-iotests/051.out
+++ b/tests/qemu-iotests/051.out
@@ -75,6 +75,19 @@ Testing: -drive
file=TEST_DIR/t.qcow2,file.backing.driver=qcow2,file.backing.fil
QEMU_PROG: -drive
file=TEST_DIR/t.qcow2,file.backing.driver=qcow2,file.backing.file.filename=TEST_DIR/t.qcow2.orig:
Driver doesn't support backing files
+=== Backing file reference ===
+
+Testing: -drive file=TEST_DIR/t.qcow2,if=none,id=drive0 -drive
file=TEST_DIR/t.qcow2,driver=qcow2,backing_reference.drive_id=drive0,backing_reference.hidden-disk.filename=TEST_DIR/t.qcow2.hidden
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) q[K[Dqu[K[D[Dqui[K[D[D[Dquit[K
+
+Testing: -drive file=TEST_DIR/t.qcow2,if=none,id=drive0 -drive
file=TEST_DIR/t.qcow2,driver=qcow2,backing_reference.drive_id=drive0,backing_reference.hidden-disk.filename=TEST_DIR/t.qcow2.hidden,backing.file.filename=TEST_DIR/t.qcow2.orig
+QEMU_PROG: -drive
file=TEST_DIR/t.qcow2,driver=qcow2,backing=drive0,backing.file.filename=TEST_DIR/t.qcow2.orig:
Option "backing_reference.*" and "backing.*" cannot be used together
+
+Testing: -drive file=TEST_DIR/t.qcow2,if=none,id=drive0 -drive
file=TEST_DIR/t.qcow2,driver=qcow2,file.backing_reference.drive_id=drive0,file.backing_reference.hidden-disk.filename=TEST_DIR/t.qcow2.hidden,file.backing.file.filename=TEST_DIR/t.qcow2.orig
+QEMU_PROG: -drive
file=TEST_DIR/t.qcow2,driver=qcow2,file.backing=drive0,file.backing.file.filename=TEST_DIR/t.qcow2.orig:
Option "backing_reference.*" and "backing.*" cannot be used together
+
+
=== Enable and disable lazy refcounting on the command line, plus some invalid
values ===
Testing: -drive file=TEST_DIR/t.qcow2,format=qcow2,lazy-refcounts=on
--
2.1.0
