From 495319483ab87ea4b2204f448ccb25dab9db857d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 3 Feb 2011 23:48:59 -0200 Subject: [PATCH 02/15] block: add block_resize monitor command RH-Author: Christoph Hellwig Message-id: <1296776941-22666-2-git-send-email-chellwig@redhat.com> Patchwork-id: 17656 O-Subject: [RHEL6 qemu PATCH 2/4 v2] block: add block_resize monitor command Bugzilla: 515775 RH-Acked-by: Juan Quintela RH-Acked-by: Kevin Wolf RH-Acked-by: Jes Sorensen 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 Upstream commit: 6d4a2b3a47959f02e7f307f50396e70e8464f95e BZ: 515775 Signed-off-by: Luiz Capitulino --- monitor.c | 30 ++++++++++++++++++++++++++++++ qemu-monitor.hx | 36 ++++++++++++++++++++++++++++++++++++ sysemu.h | 1 + 3 files changed, 67 insertions(+), 0 deletions(-) diff --git a/monitor.c b/monitor.c index ea4fd56..afed4bc 100644 --- a/monitor.c +++ b/monitor.c @@ -1115,6 +1115,36 @@ out: return ret; } +/* + * 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; +} + static int eject_device(Monitor *mon, BlockDriverState *bs, int force) { if (!force) { diff --git a/qemu-monitor.hx b/qemu-monitor.hx index 5fab2f8..e2c0c22 100644 --- a/qemu-monitor.hx +++ b/qemu-monitor.hx @@ -1163,6 +1163,42 @@ STEXI Snapshot device, using snapshot file as target if provided 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 +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 + #if defined(TARGET_I386) && 0 /* Disabled for Red Hat Enterprise Linux */ { .name = "drive_add", diff --git a/sysemu.h b/sysemu.h index bf6fa20..94b457e 100644 --- a/sysemu.h +++ b/sysemu.h @@ -265,6 +265,7 @@ void rtc_change_mon_event(struct tm *tm); void register_devices(void); int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data); +int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data); void add_boot_device_path(int32_t bootindex, DeviceState *dev, const char *suffix); -- 1.7.4.rc1.16.gd2f15e