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[Qemu-devel] [PATCH 1/3] block: add resize monitor command
From: |
Christoph Hellwig |
Subject: |
[Qemu-devel] [PATCH 1/3] block: add resize monitor command |
Date: |
Fri, 14 Jan 2011 17:20:57 +0100 |
User-agent: |
Mutt/1.3.28i |
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 <address@hidden>
Index: qemu/hmp-commands.hx
===================================================================
--- qemu.orig/hmp-commands.hx 2011-01-14 15:11:48.527004132 +0100
+++ qemu/hmp-commands.hx 2011-01-14 15:40:14.407006506 +0100
@@ -53,6 +53,24 @@ Quit the emulator.
ETEXI
{
+ .name = "resize",
+ .args_type = "id:s,size:l",
+ .params = "device size",
+ .help = "resize a block image",
+ .user_print = monitor_user_noop,
+ .mhandler.cmd_new = do_resize,
+ },
+
+STEXI
address@hidden resize
address@hidden resize
+Resize a block image while a guest is running. Usuaully requires guest
+action to see the updated size. Resize to a lower size is supported,
+but should be used with extreme caution.
+ETEXI
+
+
+ {
.name = "eject",
.args_type = "force:-f,device:B",
.params = "[-f] device",
Index: qemu/blockdev.c
===================================================================
--- qemu.orig/blockdev.c 2011-01-14 15:11:48.539261151 +0100
+++ qemu/blockdev.c 2011-01-14 15:50:35.604293558 +0100
@@ -700,3 +700,41 @@ int do_drive_del(Monitor *mon, const QDi
return 0;
}
+
+int do_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+ const char *id = qdict_get_str(qdict, "id");
+ int64_t size = qdict_get_int(qdict, "size");
+ BlockDriverState *bs;
+
+ bs = bdrv_find(id);
+ if (!bs) {
+ qerror_report(QERR_DEVICE_NOT_FOUND, id);
+ return -1;
+ }
+
+ if (bdrv_get_type_hint(bs) == BDRV_TYPE_CDROM) {
+ error_report("Can not resize CDROM devices\n");
+ return -1;
+ }
+
+ if (size < 0) {
+ error_report("Can only resize to positive sizes");
+ return -1;
+ }
+
+ switch (bdrv_truncate(bs, size)) {
+ case 0:
+ return 0;
+ case -ENOTSUP:
+ error_report("This image format does not support resize");
+ return -1;
+ case -EACCES:
+ error_report("Image is read-only");
+ return -1;
+ default:
+ error_report("Error resizing image");
+ return -1;
+ }
+}
+
Index: qemu/blockdev.h
===================================================================
--- qemu.orig/blockdev.h 2011-01-14 15:11:48.548263456 +0100
+++ qemu/blockdev.h 2011-01-14 15:12:00.965047363 +0100
@@ -53,5 +53,6 @@ int do_change_block(Monitor *mon, const
const char *filename, const char *fmt);
int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data);
+int do_resize(Monitor *mon, const QDict *qdict, QObject **ret_data);
#endif
- [Qemu-devel] [PATCH 0/3] allow online resizing of block devices, Christoph Hellwig, 2011/01/14
- [Qemu-devel] [PATCH 1/3] block: add resize monitor command,
Christoph Hellwig <=
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Stefan Hajnoczi, 2011/01/17
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Kevin Wolf, 2011/01/17
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Christoph Hellwig, 2011/01/18
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Christoph Hellwig, 2011/01/19
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Kevin Wolf, 2011/01/19
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Christoph Hellwig, 2011/01/19
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Kevin Wolf, 2011/01/19
- Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command, Christoph Hellwig, 2011/01/19
[Qemu-devel] [PATCH 2/3] block: tell drivers about an image resize, Christoph Hellwig, 2011/01/14