From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=54433 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PdmOa-00054Y-P7 for qemu-devel@nongnu.org; Fri, 14 Jan 2011 11:21:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PdmOY-00044F-6b for qemu-devel@nongnu.org; Fri, 14 Jan 2011 11:20:59 -0500 Received: from verein.lst.de ([213.95.11.210]:37075) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PdmOX-000449-Rf for qemu-devel@nongnu.org; Fri, 14 Jan 2011 11:20:58 -0500 Received: from verein.lst.de (localhost [127.0.0.1]) by verein.lst.de (8.12.3/8.12.3/Debian-7.1) with ESMTP id p0EGKvE5019196 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO) for ; Fri, 14 Jan 2011 17:20:57 +0100 Received: (from hch@localhost) by verein.lst.de (8.12.3/8.12.3/Debian-7.2) id p0EGKvfo019195 for qemu-devel@nongnu.org; Fri, 14 Jan 2011 17:20:57 +0100 Date: Fri, 14 Jan 2011 17:20:57 +0100 From: Christoph Hellwig Message-ID: <20110114162057.GA19184@lst.de> References: <20110114162044.GA19114@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110114162044.GA19114@lst.de> Subject: [Qemu-devel] [PATCH 1/3] block: add resize monitor command List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org 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 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 +@item resize +@findex 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