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Re: [Qemu-devel] [PATCH v3 1/3] qmp: Add command 'blockdev-backup'
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v3 1/3] qmp: Add command 'blockdev-backup' |
Date: |
Wed, 17 Dec 2014 18:41:26 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, 12/17 10:36, Markus Armbruster wrote:
> Fam Zheng <address@hidden> writes:
>
> > Similar to drive-backup, but this command uses a device id as target
> > instead of creating/opening an image file.
> >
> > Also add blocker on target bs, since the target is also a named device
> > now.
> >
> > Add check and report error for bs == target which became possible but is
> > an illegal case with introduction of blockdev-backup.
> >
> > Signed-off-by: Fam Zheng <address@hidden>
> > ---
> > block/backup.c | 28 +++++++++++++++++++++++++++
> > blockdev.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
> > qapi/block-core.json | 54
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++
> > qmp-commands.hx | 44 ++++++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 173 insertions(+)
> >
> > diff --git a/block/backup.c b/block/backup.c
> > index 792e655..b944dd4 100644
> > --- a/block/backup.c
> > +++ b/block/backup.c
> > @@ -360,6 +360,7 @@ static void coroutine_fn backup_run(void *opaque)
> > hbitmap_free(job->bitmap);
> >
> > bdrv_iostatus_disable(target);
> > + bdrv_op_unblock_all(target, job->common.blocker);
> >
> > data = g_malloc(sizeof(*data));
> > data->ret = ret;
> > @@ -379,6 +380,11 @@ void backup_start(BlockDriverState *bs,
> > BlockDriverState *target,
> > assert(target);
> > assert(cb);
> >
> > + if (bs == target) {
> > + error_setg(errp, "Source and target cannot be the same");
> > + return;
> > + }
> > +
> > if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
> > on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
> > !bdrv_iostatus_is_enabled(bs)) {
> > @@ -386,6 +392,26 @@ void backup_start(BlockDriverState *bs,
> > BlockDriverState *target,
> > return;
> > }
> >
> > + if (!bdrv_is_inserted(bs)) {
> > + error_setg(errp, "Devie is not inserted: %s",
>
> s/Devie/Device/
OK.
>
> > + bdrv_get_device_name(bs));
> > + return;
> > + }
> > +
> > + if (!bdrv_is_inserted(target)) {
> > + error_setg(errp, "Devie is not inserted: %s",
>
> Likewise.
OK.
>
> > + bdrv_get_device_name(target));
> > + return;
> > + }
> > +
> > + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
> > + return;
> > + }
> > +
> > + if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) {
> > + return;
> > + }
> > +
> > len = bdrv_getlength(bs);
> > if (len < 0) {
> > error_setg_errno(errp, -len, "unable to get length for '%s'",
> > @@ -399,6 +425,8 @@ void backup_start(BlockDriverState *bs,
> > BlockDriverState *target,
> > return;
> > }
> >
> > + bdrv_op_block_all(target, job->common.blocker);
> > +
> > job->on_source_error = on_source_error;
> > job->on_target_error = on_target_error;
> > job->target = target;
> > diff --git a/blockdev.c b/blockdev.c
> > index 57910b8..2e5068c 100644
> > --- a/blockdev.c
> > +++ b/blockdev.c
> > @@ -2156,6 +2156,8 @@ void qmp_drive_backup(const char *device, const char
> > *target,
> > aio_context = bdrv_get_aio_context(bs);
> > aio_context_acquire(aio_context);
> >
> > + /* Although backup_run has this check too, we need to use bs->drv
> > below, so
> > + * do an early check redundantly. */
> > if (!bdrv_is_inserted(bs)) {
> > error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
> > goto out;
> > @@ -2172,6 +2174,7 @@ void qmp_drive_backup(const char *device, const char
> > *target,
> > }
> > }
> >
> > + /* Early check to avoid creating target */
> > if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
> > goto out;
> > }
> > @@ -2239,6 +2242,50 @@ BlockDeviceInfoList
> > *qmp_query_named_block_nodes(Error **errp)
> > return bdrv_named_nodes_list();
> > }
> >
> > +void qmp_blockdev_backup(const char *device, const char *target,
> > + enum MirrorSyncMode sync,
> > + bool has_speed, int64_t speed,
> > + bool has_on_source_error,
> > + BlockdevOnError on_source_error,
> > + bool has_on_target_error,
> > + BlockdevOnError on_target_error,
> > + Error **errp)
> > +{
> > + BlockDriverState *bs;
> > + BlockDriverState *target_bs;
> > + Error *local_err = NULL;
> > +
> > + if (!has_speed) {
> > + speed = 0;
> > + }
> > + if (!has_on_source_error) {
> > + on_source_error = BLOCKDEV_ON_ERROR_REPORT;
> > + }
> > + if (!has_on_target_error) {
> > + on_target_error = BLOCKDEV_ON_ERROR_REPORT;
> > + }
> > +
> > + bs = bdrv_find(device);
> > + if (!bs) {
> > + error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> > + return;
> > + }
> > +
> > + target_bs = bdrv_find(target);
> > + if (!target_bs) {
> > + error_set(errp, QERR_DEVICE_NOT_FOUND, target);
> > + return;
> > + }
> > +
> > + bdrv_ref(target_bs);
> > + backup_start(bs, target_bs, speed, sync, on_source_error,
> > on_target_error,
> > + block_job_cb, bs, &local_err);
> > + if (local_err != NULL) {
> > + bdrv_unref(target_bs);
> > + error_propagate(errp, local_err);
> > + }
> > +}
> > +
> > #define DEFAULT_MIRROR_BUF_SIZE (10 << 20)
> >
> > void qmp_drive_mirror(const char *device, const char *target,
> > diff --git a/qapi/block-core.json b/qapi/block-core.json
> > index 77a0cfb..bc02bd7 100644
> > --- a/qapi/block-core.json
> > +++ b/qapi/block-core.json
> > @@ -676,6 +676,41 @@
> > '*on-target-error': 'BlockdevOnError' } }
> >
> > ##
> > +# @BlockdevBackup
> > +#
> > +# @device: the name of the device which should be copied.
> > +#
> > +# @target: the name of the backup target device.
> > +#
> > +# @sync: what parts of the disk image should be copied to the destination
> > +# (all the disk, only the sectors allocated in the topmost image, or
> > +# only new I/O).
> > +#
> > +# @speed: #optional the maximum speed, in bytes per second. The default is
> > 0,
> > +# for unlimited.
> > +#
> > +# @on-source-error: #optional the action to take on an error on the source,
> > +# default 'report'. 'stop' and 'enospc' can only be used
> > +# if the block device supports io-status (see BlockInfo).
> > +#
> > +# @on-target-error: #optional the action to take on an error on the target,
> > +# default 'report' (no limitations, since this applies to
> > +# a different block device than @device).
> > +#
> > +# Note that @on-source-error and @on-target-error only affect background
> > I/O.
> > +# If an error occurs during a guest write request, the device's
> > rerror/werror
> > +# actions will be used.
> > +#
> > +# Since: 2.3
> > +##
> > +{ 'type': 'BlockdevBackup',
> > + 'data': { 'device': 'str', 'target': 'str',
> > + 'sync': 'MirrorSyncMode',
> > + '*speed': 'int',
> > + '*on-source-error': 'BlockdevOnError',
> > + '*on-target-error': 'BlockdevOnError' } }
> > +
> > +##
> > # @blockdev-snapshot-sync
> > #
> > # Generates a synchronous snapshot of a block device.
> > @@ -795,6 +830,25 @@
> > { 'command': 'drive-backup', 'data': 'DriveBackup' }
> >
> > ##
> > +# @blockdev-backup
> > +#
> > +# Start a point-in-time copy of a block device to a new destination. The
> > +# status of ongoing blockdev-backup operations can be checked with
> > +# query-block-jobs where the BlockJobInfo.type field has the value
> > 'backup'.
> > +# The operation can be stopped before it has completed using the
> > +# block-job-cancel command.
> > +#
> > +# For the arguments, see the documentation of BlockdevBackup.
> > +#
> > +# Returns: Nothing on success.
> > +# If @device or @target is not a valid block device,
> > DeviceNotFound.
>
> Why do you need an error classes other than GenericError here?
>
Because this is what other block job commands do, and I followed the style.
> > +#
> > +# Since 2.3
> > +##
> > +{ 'command': 'blockdev-backup', 'data': 'BlockdevBackup' }
> > +
> > +
> > +##
> > # @query-named-block-nodes
> > #
> > # Get the named block driver list
> > diff --git a/qmp-commands.hx b/qmp-commands.hx
> > index 1abd619..518df0c 100644
> > --- a/qmp-commands.hx
> > +++ b/qmp-commands.hx
> > @@ -1094,6 +1094,50 @@ Example:
> > "sync": "full",
> > "target": "backup.img" } }
> > <- { "return": {} }
> > +
> > +EQMP
> > +
> > + {
> > + .name = "blockdev-backup",
> > + .args_type = "sync:s,device:B,target:B,speed:i?,"
> > + "on-source-error:s?,on-target-error:s?",
> > + .mhandler.cmd_new = qmp_marshal_input_blockdev_backup,
> > + },
> > +
> > +SQMP
> > +blockdev-backup
> > +------------
> > +
> > +The device version of drive-backup: this command takes an existing named
> > device
> > +as backup target.
> > +
> > +Arguments:
> > +
> > +- "device": the name of the device which should be copied.
> > + (json-string)
> > +- "target": the target of the new image. If the file exists, or if it is a
> > + device, the existing file/device will be used as the new
> > + destination. If it does not exist, a new file will be created.
> > + (json-string)
>
> Still copied from drive-backup without change. I don't think it's
> correct here. Either fix it, or explain to me why I'm wrong :)
Overlooked by my eyes, will fix in v5 (I posted v4 earlier in Dec and got
comments from Max that are pending to be addressed).
Thanks for reviewing!
Fam
>
> > +- "sync": what parts of the disk image should be copied to the destination;
> > + possibilities include "full" for all the disk, "top" for only the
> > + sectors allocated in the topmost image, or "none" to only
> > replicate
> > + new I/O (MirrorSyncMode).
> > +- "speed": the maximum speed, in bytes per second (json-int, optional)
> > +- "on-source-error": the action to take on an error on the source, default
> > + 'report'. 'stop' and 'enospc' can only be used
> > + if the block device supports io-status.
> > + (BlockdevOnError, optional)
> > +- "on-target-error": the action to take on an error on the target, default
> > + 'report' (no limitations, since this applies to
> > + a different block device than device).
> > + (BlockdevOnError, optional)
> > +
> > +Example:
> > +-> { "execute": "blockdev-backup", "arguments": { "device": "src-id",
> > + "target": "tgt-id" } }
> > +<- { "return": {} }
> > +
> > EQMP
> >
> > {