block: add block_resize monitor command
Add a monitor command that allows resizing of block devices while
qemu is running. It uses the existing bdrv_truncate method already
used by qemu-img to do it's work. Compared to qemu-img the size
parsing is very simplicistic, but I think having a properly numering
object is more useful for non-humand monitor users than having
the units and relative resize parsing.
For SCSI devices the new size can be updated in Linux guests by
doing the following shell command:
echo > /sys/class/scsi_device/0:0:0:0/device/rescan
For ATA devices I don't know of a way to update the block device
size in Linux system, and for virtio-blk the next two patches
will provide an automatic update of the size when this command
is issued on the host.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/blockdev.c b/blockdev.c
index f7f591f..e48d33d 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -705,3 +705,33 @@
return 0;
}
+
+/*
+ * XXX: replace the QERR_UNDEFINED_ERROR errors with real values once the
+ * existing QERR_ macro mess is cleaned up. A good example for better
+ * error reports can be found in the qemu-img resize code.
+ */
+int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+ const char *device = qdict_get_str(qdict, "device");
+ int64_t size = qdict_get_int(qdict, "size");
+ BlockDriverState *bs;
+
+ bs = bdrv_find(device);
+ if (!bs) {
+ qerror_report(QERR_DEVICE_NOT_FOUND, device);
+ return -1;
+ }
+
+ if (size < 0) {
+ qerror_report(QERR_UNDEFINED_ERROR);
+ return -1;
+ }
+
+ if (bdrv_truncate(bs, size)) {
+ qerror_report(QERR_UNDEFINED_ERROR);
+ return -1;
+ }
+
+ return 0;
+}
