From: Omri Mann <omri@xxxxxxxxxx>
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: Omri Mann <omri@xxxxxxxxxx>
---
drivers/block/ublk_drv.c | 19 ++++++++++++++++++-
include/uapi/linux/ublk_cmd.h | 8 ++++++++
2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 2de7b2bd409d..03653bd7a1df 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -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;
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 583b86681c93..be5c6c6b16e0 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -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
--
2.43.0
