From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=42830 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PjvfX-0002WC-Hd for qemu-devel@nongnu.org; Mon, 31 Jan 2011 10:27:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PjvfM-0003OE-Dc for qemu-devel@nongnu.org; Mon, 31 Jan 2011 10:27:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:22749) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PjvfM-0003O2-68 for qemu-devel@nongnu.org; Mon, 31 Jan 2011 10:27:44 -0500 From: Kevin Wolf Date: Mon, 31 Jan 2011 16:28:53 +0100 Message-Id: <1296487756-12553-6-git-send-email-kwolf@redhat.com> In-Reply-To: <1296487756-12553-1-git-send-email-kwolf@redhat.com> References: <1296487756-12553-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH 05/28] block: add block_resize monitor command List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: anthony@codemonkey.ws Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: Christoph Hellwig 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 Signed-off-by: Kevin Wolf --- blockdev.c | 30 ++++++++++++++++++++++++++++++ blockdev.h | 1 + hmp-commands.hx | 19 +++++++++++++++++++ qmp-commands.hx | 28 ++++++++++++++++++++++++++++ 4 files changed, 78 insertions(+), 0 deletions(-) diff --git a/blockdev.c b/blockdev.c index f7f591f..e48d33d 100644 --- a/blockdev.c +++ b/blockdev.c @@ -705,3 +705,33 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data) 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; +} diff --git a/blockdev.h b/blockdev.h index 4536b5c..b8a88bf 100644 --- a/blockdev.h +++ b/blockdev.h @@ -53,5 +53,6 @@ int do_change_block(Monitor *mon, const char *device, 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_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data); #endif diff --git a/hmp-commands.hx b/hmp-commands.hx index 1cea572..8df4adf 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -53,6 +53,25 @@ Quit the emulator. ETEXI { + .name = "block_resize", + .args_type = "device:B,size:o", + .params = "device size", + .help = "resize a block image", + .user_print = monitor_user_noop, + .mhandler.cmd_new = do_block_resize, + }, + +STEXI +@item block_resize +@findex block_resize +Resize a block image while a guest is running. Usually requires guest +action to see the updated size. Resize to a lower size is supported, +but should be used with extreme caution. Note that this command only +resizes image files, it can not resize block devices like LVM volumes. +ETEXI + + + { .name = "eject", .args_type = "force:-f,device:B", .params = "[-f] device", diff --git a/qmp-commands.hx b/qmp-commands.hx index 56c4d8b..9f79f5f 100644 --- a/qmp-commands.hx +++ b/qmp-commands.hx @@ -601,6 +601,34 @@ Example: -> { "execute": "netdev_del", "arguments": { "id": "netdev1" } } <- { "return": {} } + +EQMP + + { + .name = "block_resize", + .args_type = "device:B,size:o", + .params = "device size", + .help = "resize a block image", + .user_print = monitor_user_noop, + .mhandler.cmd_new = do_block_resize, + }, + +SQMP +block_resize +------------ + +Resize a block image while a guest is running. + +Arguments: + +- "device": the device's ID, must be unique (json-string) +- "size": new size + +Example: + +-> { "execute": "block_resize", "arguments": { "device": "scratch", "size": 1073741824 } } +<- { "return": {} } + EQMP { -- 1.7.2.3