block: add drive_backup HMP command

Make "drive_backup" available on the HMP monitor:

  drive_backup [-n] [-f] device target [format]

The -n flag requests QEMU to reuse the image found in new-image-file,
instead of recreating it from scratch.

The -f flag requests QEMU to copy the whole disk, so that the result
does not need a backing file.  Note that this flag *must* currently be
passed since the other sync modes ('none' and 'top') have not been
implemented yet.  Requiring it ensures that "drive_backup" behaves like
"drive_mirror".

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2013-06-26 14:11:58 +02:00 committed by Kevin Wolf
parent b53169eae0
commit de90930a0c
3 changed files with 49 additions and 0 deletions

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@ -1056,6 +1056,26 @@ STEXI
@findex drive_mirror
Start mirroring a block device's writes to a new destination,
using the specified target.
ETEXI
{
.name = "drive_backup",
.args_type = "reuse:-n,full:-f,device:B,target:s,format:s?",
.params = "[-n] [-f] device target [format]",
.help = "initiates a point-in-time\n\t\t\t"
"copy for a device. The device's contents are\n\t\t\t"
"copied to the new image file, excluding data that\n\t\t\t"
"is written after the command is started.\n\t\t\t"
"The -n flag requests QEMU to reuse the image found\n\t\t\t"
"in new-image-file, instead of recreating it from scratch.\n\t\t\t"
"The -f flag requests QEMU to copy the whole disk,\n\t\t\t"
"so that the result does not need a backing file.\n\t\t\t",
.mhandler.cmd = hmp_drive_backup,
},
STEXI
@item drive_backup
@findex drive_backup
Start a point-in-time copy of a block device to a specificed target.
ETEXI
{

28
hmp.c
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@ -907,6 +907,34 @@ void hmp_drive_mirror(Monitor *mon, const QDict *qdict)
hmp_handle_error(mon, &errp);
}
void hmp_drive_backup(Monitor *mon, const QDict *qdict)
{
const char *device = qdict_get_str(qdict, "device");
const char *filename = qdict_get_str(qdict, "target");
const char *format = qdict_get_try_str(qdict, "format");
int reuse = qdict_get_try_bool(qdict, "reuse", 0);
int full = qdict_get_try_bool(qdict, "full", 0);
enum NewImageMode mode;
Error *errp = NULL;
if (!filename) {
error_set(&errp, QERR_MISSING_PARAMETER, "target");
hmp_handle_error(mon, &errp);
return;
}
if (reuse) {
mode = NEW_IMAGE_MODE_EXISTING;
} else {
mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
}
qmp_drive_backup(device, filename, !!format, format,
full ? MIRROR_SYNC_MODE_FULL : MIRROR_SYNC_MODE_TOP,
true, mode, false, 0, false, 0, false, 0, &errp);
hmp_handle_error(mon, &errp);
}
void hmp_snapshot_blkdev(Monitor *mon, const QDict *qdict)
{
const char *device = qdict_get_str(qdict, "device");

1
hmp.h
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@ -55,6 +55,7 @@ void hmp_balloon(Monitor *mon, const QDict *qdict);
void hmp_block_resize(Monitor *mon, const QDict *qdict);
void hmp_snapshot_blkdev(Monitor *mon, const QDict *qdict);
void hmp_drive_mirror(Monitor *mon, const QDict *qdict);
void hmp_drive_backup(Monitor *mon, const QDict *qdict);
void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict);
void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);