[PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[Jared Holzman]

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 for 
this command.

Signed-off-by: Omri Mann <omri@nvidia.com>
---
  drivers/block/ublk_drv.c      | 18 +++++++++++++++++-
  include/uapi/linux/ublk_cmd.h |  7 +++++++
  2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index cdb1543fa4a9..128f094efbad 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -64,7 +64,8 @@
          | 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 \
@@ -3067,6 +3068,16 @@ 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
@@ -3152,6 +3163,7 @@ 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 _IOC_NR(UBLK_U_CMD_UPDATE_SIZE):
          mask = MAY_READ | MAY_WRITE;
          break;
      default:
@@ -3243,6 +3255,10 @@ 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 _IOC_NR(UBLK_U_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..587a54b3cfe1 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 +213,11 @@
   */
  #define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)

+/*
+ * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE
+ */
+#define UBLK_F_UPDATE_SIZE         (1ULL << 10)
+
  /* device state */
  #define UBLK_S_DEV_DEAD    0
  #define UBLK_S_DEV_LIVE    1
-- 
2.43.0

Re: [PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[Uday Shankar]

On Wed, Apr 16, 2025 at 01:07:47PM +0300, Jared Holzman wrote:
> 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.

Many of the other parameters in ublk_params/ublksrv_ctrl_dev_info could
also feasibly be changed after initial device creation/start. Is it
possible to design the API in a way so that we don't have to have one
command per parameter?

> Feature flag UBLK_F_UPDATE_SIZE is also added to indicate support for this
> command.
> 
> Signed-off-by: Omri Mann <omri@nvidia.com>
> ---
>  drivers/block/ublk_drv.c      | 18 +++++++++++++++++-
>  include/uapi/linux/ublk_cmd.h |  7 +++++++
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index cdb1543fa4a9..128f094efbad 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -64,7 +64,8 @@
>          | 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 \
> @@ -3067,6 +3068,16 @@ 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
> @@ -3152,6 +3163,7 @@ 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 _IOC_NR(UBLK_U_CMD_UPDATE_SIZE):
>          mask = MAY_READ | MAY_WRITE;
>          break;
>      default:
> @@ -3243,6 +3255,10 @@ 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 _IOC_NR(UBLK_U_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..587a54b3cfe1 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 +213,11 @@
>   */
>  #define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)
> 
> +/*
> + * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE
> + */
> +#define UBLK_F_UPDATE_SIZE         (1ULL << 10)
> +
>  /* device state */
>  #define UBLK_S_DEV_DEAD    0
>  #define UBLK_S_DEV_LIVE    1
> -- 
> 2.43.0
> 
> 

Re: [PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[Jared Holzman]

On 17/04/2025 21:23, Uday Shankar wrote:
> On Wed, Apr 16, 2025 at 01:07:47PM +0300, Jared Holzman wrote:
>> 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.
> Many of the other parameters in ublk_params/ublksrv_ctrl_dev_info could
> also feasibly be changed after initial device creation/start. Is it
> possible to design the API in a way so that we don't have to have one
> command per parameter?

Already spoke to Ming about this. Changing the size is reasonable and 
easy with a simple api call i.e. set_capacity_and_notify()

Changing the other parameters I struggle to see a reasonable need for it 
and is significantly more complicated.

>
>> Feature flag UBLK_F_UPDATE_SIZE is also added to indicate support for this
>> command.
>>
>> Signed-off-by: Omri Mann <omri@nvidia.com>
>> ---
>>   drivers/block/ublk_drv.c      | 18 +++++++++++++++++-
>>   include/uapi/linux/ublk_cmd.h |  7 +++++++
>>   2 files changed, 24 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index cdb1543fa4a9..128f094efbad 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -64,7 +64,8 @@
>>           | 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 \
>> @@ -3067,6 +3068,16 @@ 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
>> @@ -3152,6 +3163,7 @@ 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 _IOC_NR(UBLK_U_CMD_UPDATE_SIZE):
>>           mask = MAY_READ | MAY_WRITE;
>>           break;
>>       default:
>> @@ -3243,6 +3255,10 @@ 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 _IOC_NR(UBLK_U_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..587a54b3cfe1 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 +213,11 @@
>>    */
>>   #define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)
>>
>> +/*
>> + * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE
>> + */
>> +#define UBLK_F_UPDATE_SIZE         (1ULL << 10)
>> +
>>   /* device state */
>>   #define UBLK_S_DEV_DEAD    0
>>   #define UBLK_S_DEV_LIVE    1
>> -- 
>> 2.43.0
>>
>>
-- 
Jared Holzman
Senior Software Engineer
NVIDIA
jholzman@nvidia.com

Re: [PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[Ming Lei]

On Wed, Apr 16, 2025 at 01:07:47PM +0300, Jared Holzman wrote:
> 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 for this
> command.
> 
> Signed-off-by: Omri Mann <omri@nvidia.com>
> ---
>  drivers/block/ublk_drv.c      | 18 +++++++++++++++++-
>  include/uapi/linux/ublk_cmd.h |  7 +++++++
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index cdb1543fa4a9..128f094efbad 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -64,7 +64,8 @@
>          | 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 \
> @@ -3067,6 +3068,16 @@ static int ublk_ctrl_get_features(const struct
> ublksrv_ctrl_cmd *header)

I try to apply this patch downloaded from both lore or patchwork, and 'git
am' always complains the patch is broken:

[root@ktest-40 linux]# git am raw
warning: Patch sent with format=flowed; space at the end of lines might be lost.
Applying: ublk: Add UBLK_U_CMD_UPDATE_SIZE
error: corrupt patch at line 11
Patch failed at 0001 ublk: Add UBLK_U_CMD_UPDATE_SIZE
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
[root@ktest-40 linux]# patch -p1 < raw
patching file drivers/block/ublk_drv.c
Hunk #1 FAILED at 64.
patch: **** malformed patch at line 192: ublksrv_ctrl_cmd *header)

Please use 'git-format-patch' to make patch and run `./scripts/checkpatch.pl -g HEAD`
in kernel top directory to make sure no ERROR.

>      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
> @@ -3152,6 +3163,7 @@ 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 _IOC_NR(UBLK_U_CMD_UPDATE_SIZE):

Here it could be more clean to add one private definition:

	#define UBLK_CMD_UPDATE_SIZE _IOC_NR(UBLK_U_CMD_UPDATE_SIZE)

just like what we did for `UBLK_CMD_DEL_DEV_ASYNC`.

Then use UBLK_CMD_UPDATE_SIZE directly.

>          mask = MAY_READ | MAY_WRITE;
>          break;
>      default:
> @@ -3243,6 +3255,10 @@ 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 _IOC_NR(UBLK_U_CMD_UPDATE_SIZE):

Same with above.

> +        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..587a54b3cfe1 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 +213,11 @@
>   */
>  #define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)
> 
> +/*
> + * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE
> + */
> +#define UBLK_F_UPDATE_SIZE         (1ULL << 10)

Please document how size is passed, and the unit is sector.

With above addressed, this patch looks fine.


Thanks,
Ming

Re: [PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[Jared Holzman]

On 18/04/2025 2:35, Ming Lei wrote:
> On Wed, Apr 16, 2025 at 01:07:47PM +0300, Jared Holzman wrote:
>> 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 for this
>> command.
>>
>> Signed-off-by: Omri Mann <omri@nvidia.com>
>> ---
>>   drivers/block/ublk_drv.c      | 18 +++++++++++++++++-
>>   include/uapi/linux/ublk_cmd.h |  7 +++++++
>>   2 files changed, 24 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index cdb1543fa4a9..128f094efbad 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -64,7 +64,8 @@
>>           | 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 \
>> @@ -3067,6 +3068,16 @@ static int ublk_ctrl_get_features(const struct
>> ublksrv_ctrl_cmd *header)
> 
> I try to apply this patch downloaded from both lore or patchwork, and 'git
> am' always complains the patch is broken:

I think this is because of my workflow. I cannot send email outside of 
our network using git send-mail so I've been copy-pasting the patch into 
Thunderbird.

I will try instead sending the mail from git send-mail to my account and 
then forwarding from there.


> 
> [root@ktest-40 linux]# git am raw
> warning: Patch sent with format=flowed; space at the end of lines might be lost.
> Applying: ublk: Add UBLK_U_CMD_UPDATE_SIZE
> error: corrupt patch at line 11
> Patch failed at 0001 ublk: Add UBLK_U_CMD_UPDATE_SIZE
> hint: Use 'git am --show-current-patch=diff' to see the failed patch
> hint: When you have resolved this problem, run "git am --continue".
> hint: If you prefer to skip this patch, run "git am --skip" instead.
> hint: To restore the original branch and stop patching, run "git am --abort".
> hint: Disable this message with "git config advice.mergeConflict false"
> [root@ktest-40 linux]# patch -p1 < raw
> patching file drivers/block/ublk_drv.c
> Hunk #1 FAILED at 64.
> patch: **** malformed patch at line 192: ublksrv_ctrl_cmd *header)
> 
> Please use 'git-format-patch' to make patch and run `./scripts/checkpatch.pl -g HEAD`
> in kernel top directory to make sure no ERROR.
> 
>>       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
>> @@ -3152,6 +3163,7 @@ 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 _IOC_NR(UBLK_U_CMD_UPDATE_SIZE):
> 
> Here it could be more clean to add one private definition:

Will do.

> 
> 	#define UBLK_CMD_UPDATE_SIZE _IOC_NR(UBLK_U_CMD_UPDATE_SIZE)
> 
> just like what we did for `UBLK_CMD_DEL_DEV_ASYNC`.
> 
> Then use UBLK_CMD_UPDATE_SIZE directly.
> 
>>           mask = MAY_READ | MAY_WRITE;
>>           break;
>>       default:
>> @@ -3243,6 +3255,10 @@ 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 _IOC_NR(UBLK_U_CMD_UPDATE_SIZE):
> 
> Same with above.

Ack

> 
>> +        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..587a54b3cfe1 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 +213,11 @@
>>    */
>>   #define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)
>>
>> +/*
>> + * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE
>> + */
>> +#define UBLK_F_UPDATE_SIZE         (1ULL << 10)
> 
> Please document how size is passed, and the unit is sector.

Ack
> 
> With above addressed, this patch looks fine.

Great. I'll make the changes and send a new version. Let's hope it works 
this time.
> 
> 
> Thanks,
> Ming
> 

-- 
Jared Holzman
Senior Software Engineer
NVIDIA
jholzman@nvidia.com

Re: [PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[Ming Lei]

On Sun, Apr 20, 2025 at 11:06:17AM +0300, Jared Holzman wrote:
> 
> 
> On 18/04/2025 2:35, Ming Lei wrote:
> > On Wed, Apr 16, 2025 at 01:07:47PM +0300, Jared Holzman wrote:
> > > 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 for this
> > > command.
> > > 
> > > Signed-off-by: Omri Mann <omri@nvidia.com>
> > > ---
> > >   drivers/block/ublk_drv.c      | 18 +++++++++++++++++-
> > >   include/uapi/linux/ublk_cmd.h |  7 +++++++
> > >   2 files changed, 24 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> > > index cdb1543fa4a9..128f094efbad 100644
> > > --- a/drivers/block/ublk_drv.c
> > > +++ b/drivers/block/ublk_drv.c
> > > @@ -64,7 +64,8 @@
> > >           | 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 \
> > > @@ -3067,6 +3068,16 @@ static int ublk_ctrl_get_features(const struct
> > > ublksrv_ctrl_cmd *header)
> > 
> > I try to apply this patch downloaded from both lore or patchwork, and 'git
> > am' always complains the patch is broken:
> 
> I think this is because of my workflow. I cannot send email outside of our
> network using git send-mail so I've been copy-pasting the patch into
> Thunderbird.

oops, copy-paste usually breaks patch style, probably `xclip` can help you
if copy-paste can't be avoided.

You probably need to find one email client to support importing patch plain
text from file or sending patch directly, such as mutt/msmtp,...

Thanks,
Ming

Re: [PATCH v4]: ublk: Add UBLK_U_CMD_UPDATE_SIZE

[Jared Holzman]

On 21/04/2025 5:51, Ming Lei wrote:
> On Sun, Apr 20, 2025 at 11:06:17AM +0300, Jared Holzman wrote:
>>
>>
>> On 18/04/2025 2:35, Ming Lei wrote:
>>> On Wed, Apr 16, 2025 at 01:07:47PM +0300, Jared Holzman wrote:
>>>> 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 for this
>>>> command.
>>>>
>>>> Signed-off-by: Omri Mann <omri@nvidia.com>
>>>> ---
>>>>   drivers/block/ublk_drv.c      | 18 +++++++++++++++++-
>>>>   include/uapi/linux/ublk_cmd.h |  7 +++++++
>>>>   2 files changed, 24 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>>>> index cdb1543fa4a9..128f094efbad 100644
>>>> --- a/drivers/block/ublk_drv.c
>>>> +++ b/drivers/block/ublk_drv.c
>>>> @@ -64,7 +64,8 @@
>>>>           | 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 \
>>>> @@ -3067,6 +3068,16 @@ static int ublk_ctrl_get_features(const struct
>>>> ublksrv_ctrl_cmd *header)
>>>
>>> I try to apply this patch downloaded from both lore or patchwork, and 'git
>>> am' always complains the patch is broken:
>>
>> I think this is because of my workflow. I cannot send email outside of our
>> network using git send-mail so I've been copy-pasting the patch into
>> Thunderbird.
> 
> oops, copy-paste usually breaks patch style, probably `xclip` can help you
> if copy-paste can't be avoided.

Apparently Thunderbird also breaks patch style by default. I had to change some settings.

> 
> You probably need to find one email client to support importing patch plain
> text from file or sending patch directly, such as mutt/msmtp,...

Should be good now. Please see v6 of the patch I just sent. I already tried downloading and applying it myself and it works.

Apologies for the noise.


> 
> Thanks,
> Ming
>