Commit 98b99566 authored by Omri Mann's avatar Omri Mann Committed by Jens Axboe
Browse files

ublk: Add UBLK_U_CMD_UPDATE_SIZE 



Currently ublk only allows the size of the ublkb block device to be
set via UBLK_CMD_SET_PARAMS before UBLK_CMD_START_DEV is triggered.

This does not provide support for extendable user-space block devices
without having to stop and restart the underlying ublkb block device
causing IO interruption.

This patch adds a new ublk command UBLK_U_CMD_UPDATE_SIZE to allow the
ublk block device to be resized on-the-fly.

Feature flag UBLK_F_UPDATE_SIZE is also added to indicate support.

Signed-off-by: default avatarOmri Mann <omri@nvidia.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/2a370ab1-d85b-409d-b762-f9f3f6bdf705@nvidia.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 033b667a

drivers/block/ublk_drv.c

+18 −1
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ 


/* private ioctl command mirror */

#define UBLK_CMD_DEL_DEV_ASYNC	_IOC_NR(UBLK_U_CMD_DEL_DEV_ASYNC)

#define UBLK_CMD_UPDATE_SIZE	_IOC_NR(UBLK_U_CMD_UPDATE_SIZE)



#define UBLK_IO_REGISTER_IO_BUF		_IOC_NR(UBLK_U_IO_REGISTER_IO_BUF)

#define UBLK_IO_UNREGISTER_IO_BUF	_IOC_NR(UBLK_U_IO_UNREGISTER_IO_BUF)
@@ -64,7 +65,8 @@ 
		| UBLK_F_CMD_IOCTL_ENCODE \

		| UBLK_F_USER_COPY \

		| UBLK_F_ZONED \

		| UBLK_F_USER_RECOVERY_FAIL_IO)

		| UBLK_F_USER_RECOVERY_FAIL_IO \

		| UBLK_F_UPDATE_SIZE)



#define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \

		| UBLK_F_USER_RECOVERY_REISSUE \
@@ -3075,6 +3077,16 @@ static int ublk_ctrl_get_features(const struct ublksrv_ctrl_cmd *header) 
	return 0;

}



static void ublk_ctrl_set_size(struct ublk_device *ub, const struct ublksrv_ctrl_cmd *header)

{

	struct ublk_param_basic *p = &ub->params.basic;

	u64 new_size = header->data[0];



	mutex_lock(&ub->mutex);

	p->dev_sectors = new_size;

	set_capacity_and_notify(ub->ub_disk, p->dev_sectors);

	mutex_unlock(&ub->mutex);

}

/*

 * All control commands are sent via /dev/ublk-control, so we have to check

 * the destination device's permission
@@ -3160,6 +3172,7 @@ static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub, 
	case UBLK_CMD_SET_PARAMS:

	case UBLK_CMD_START_USER_RECOVERY:

	case UBLK_CMD_END_USER_RECOVERY:

	case UBLK_CMD_UPDATE_SIZE:

		mask = MAY_READ | MAY_WRITE;

		break;

	default:
@@ -3251,6 +3264,10 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, 
	case UBLK_CMD_END_USER_RECOVERY:

		ret = ublk_ctrl_end_recovery(ub, header);

		break;

	case UBLK_CMD_UPDATE_SIZE:

		ublk_ctrl_set_size(ub, header);

		ret = 0;

		break;

	default:

		ret = -EOPNOTSUPP;

		break;

include/uapi/linux/ublk_cmd.h

+8 −0
Original line number Diff line number Diff line
@@ -51,6 +51,8 @@ 
	_IOR('u', 0x13, struct ublksrv_ctrl_cmd)

#define UBLK_U_CMD_DEL_DEV_ASYNC	\

	_IOR('u', 0x14, struct ublksrv_ctrl_cmd)

#define UBLK_U_CMD_UPDATE_SIZE		\

	_IOWR('u', 0x15, struct ublksrv_ctrl_cmd)



/*

 * 64bits are enough now, and it should be easy to extend in case of
@@ -211,6 +213,12 @@ 
 */

#define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)



/*

 * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE

 * New size is passed in cmd->data[0] and is in units of sectors

 */

#define UBLK_F_UPDATE_SIZE		 (1ULL << 10)



/* device state */

#define UBLK_S_DEV_DEAD	0

#define UBLK_S_DEV_LIVE	1