| Message ID | 20110119170248.GA9819@lst.de |
|---|---|
| State | New |
| Headers | show |
On Wed, Jan 19, 2011 at 06:02:48PM +0100, Christoph Hellwig wrote: > Index: qemu/hmp-commands.hx > =================================================================== > --- qemu.orig/hmp-commands.hx 2011-01-19 17:47:10.444004409 +0100 > +++ qemu/hmp-commands.hx 2011-01-19 17:49:51.673254095 +0100 > @@ -53,6 +53,25 @@ Quit the emulator. > ETEXI > > { > + .name = "resize", > + .args_type = "id:s,size:o", > + .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. 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", [...] > Index: qemu/qmp-commands.hx > =================================================================== > --- qemu.orig/qmp-commands.hx 2011-01-19 17:47:10.478012371 +0100 > +++ qemu/qmp-commands.hx 2011-01-19 17:50:07.406016841 +0100 > @@ -601,6 +601,34 @@ Example: > -> { "execute": "netdev_del", "arguments": { "id": "netdev1" } } > <- { "return": {} } > > + > +EQMP > + > + { > + .name = "block_resize", > + .args_type = "id:s,size:o", > + .params = "id size", > + .help = "resize a block image", > + .user_print = monitor_user_noop, > + .mhandler.cmd_new = do_resize, > + }, > + > +SQMP > +block_resize > +------------ > + > +Resize a block image while a guest is running. > + > +Arguments: > + > +- "id": the device's ID, must be unique (json-string) > +- "size": new size > + > +Example: > + > +-> { "execute": "block_resize", "arguments": { "id": "scratch", "size": 1073741824 } } > +<- { "return": {} } > + > EQMP eject, change, block_passwd, and others call the device name argument "device" instead of "id". In the interest of a consistent external API it would be nice to use "device" for the block_resize command too. Stefan
On Thu, Jan 20, 2011 at 08:56:07AM +0000, Stefan Hajnoczi wrote: > eject, change, block_passwd, and others call the device name argument > "device" instead of "id". In the interest of a consistent external API > it would be nice to use "device" for the block_resize command too. Sure, I can do that with the next respin.
Index: qemu/hmp-commands.hx =================================================================== --- qemu.orig/hmp-commands.hx 2011-01-19 17:47:10.444004409 +0100 +++ qemu/hmp-commands.hx 2011-01-19 17:49:51.673254095 +0100 @@ -53,6 +53,25 @@ Quit the emulator. ETEXI { + .name = "resize", + .args_type = "id:s,size:o", + .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. 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", Index: qemu/blockdev.c =================================================================== --- qemu.orig/blockdev.c 2011-01-19 17:47:10.455004828 +0100 +++ qemu/blockdev.c 2011-01-19 17:49:51.674253955 +0100 @@ -706,3 +706,33 @@ int do_drive_del(Monitor *mon, const QDi 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_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 (size < 0) { + qerror_report(QERR_UNDEFINED_ERROR); + return -1; + } + + if (bdrv_truncate(bs, size)) { + qerror_report(QERR_UNDEFINED_ERROR); + return -1; + } + + return 0; +} Index: qemu/blockdev.h =================================================================== --- qemu.orig/blockdev.h 2011-01-19 17:47:10.464012091 +0100 +++ qemu/blockdev.h 2011-01-19 17:49:51.677282590 +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 Index: qemu/qmp-commands.hx =================================================================== --- qemu.orig/qmp-commands.hx 2011-01-19 17:47:10.478012371 +0100 +++ qemu/qmp-commands.hx 2011-01-19 17:50:07.406016841 +0100 @@ -601,6 +601,34 @@ Example: -> { "execute": "netdev_del", "arguments": { "id": "netdev1" } } <- { "return": {} } + +EQMP + + { + .name = "block_resize", + .args_type = "id:s,size:o", + .params = "id size", + .help = "resize a block image", + .user_print = monitor_user_noop, + .mhandler.cmd_new = do_resize, + }, + +SQMP +block_resize +------------ + +Resize a block image while a guest is running. + +Arguments: + +- "id": the device's ID, must be unique (json-string) +- "size": new size + +Example: + +-> { "execute": "block_resize", "arguments": { "id": "scratch", "size": 1073741824 } } +<- { "return": {} } + EQMP {
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>