diff mbox series

[06/10] dasd: implement ->set_read_only to hook into BLKROSET processing

Message ID 20201103100018.683694-7-hch@lst.de (mailing list archive)
State New, archived
Headers show
Series [01/10] mtd_blkdevs: don't override BLKFLSBUF | expand

Commit Message

Christoph Hellwig Nov. 3, 2020, 10 a.m. UTC 
Implement the ->set_read_only method instead of parsing the actual
ioctl command.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/s390/block/dasd.c       |  1 +
 drivers/s390/block/dasd_int.h   |  3 ++-
 drivers/s390/block/dasd_ioctl.c | 27 +++++++++------------------
 3 files changed, 12 insertions(+), 19 deletions(-)

Comments

Stefan Haberland Nov. 5, 2020, 8:56 p.m. UTC | #1 
Christoph Hellwig <hch@lst.de> schrieb am Tue, 03. Nov 11:00:
> Implement the ->set_read_only method instead of parsing the actual
> ioctl command.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/s390/block/dasd.c       |  1 +
>  drivers/s390/block/dasd_int.h   |  3 ++-
>  drivers/s390/block/dasd_ioctl.c | 27 +++++++++------------------
>  3 files changed, 12 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
> index eb17fea8075c6f..db24e04ee9781e 100644
> --- a/drivers/s390/block/dasd.c
> +++ b/drivers/s390/block/dasd.c
> @@ -3394,6 +3394,7 @@ dasd_device_operations = {
>  	.ioctl		= dasd_ioctl,
>  	.compat_ioctl	= dasd_ioctl,
>  	.getgeo		= dasd_getgeo,
> +	.set_read_only	= dasd_set_read_only,
>  };
>  
>  /*******************************************************************************
> diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
> index fa552f9f166671..c59a0d63b506e6 100644
> --- a/drivers/s390/block/dasd_int.h
> +++ b/drivers/s390/block/dasd_int.h
> @@ -844,7 +844,8 @@ int dasd_scan_partitions(struct dasd_block *);
>  void dasd_destroy_partitions(struct dasd_block *);
>  
>  /* externals in dasd_ioctl.c */
> -int  dasd_ioctl(struct block_device *, fmode_t, unsigned int, unsigned long);
> +int dasd_ioctl(struct block_device *, fmode_t, unsigned int, unsigned long);
> +int dasd_set_read_only(struct block_device *bdev, bool ro);
>  
>  /* externals in dasd_proc.c */
>  int dasd_proc_init(void);
> diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
> index cb6427fb9f3d16..3359559517bfcf 100644
> --- a/drivers/s390/block/dasd_ioctl.c
> +++ b/drivers/s390/block/dasd_ioctl.c
> @@ -532,28 +532,22 @@ static int dasd_ioctl_information(struct dasd_block *block, void __user *argp,
>  /*
>   * Set read only
>   */
> -static int
> -dasd_ioctl_set_ro(struct block_device *bdev, void __user *argp)
> +int dasd_set_read_only(struct block_device *bdev, bool ro)
>  {
>  	struct dasd_device *base;
> -	int intval, rc;
> +	int rc;
>  
> -	if (!capable(CAP_SYS_ADMIN))
> -		return -EACCES;
> +	/* do not manipulate hardware state for partitions */
>  	if (bdev_is_partition(bdev))
> -		// ro setting is not allowed for partitions
> -		return -EINVAL;
> -	if (get_user(intval, (int __user *)argp))
> -		return -EFAULT;
> +		return 0;
> +
>  	base = dasd_device_from_gendisk(bdev->bd_disk);
>  	if (!base)
>  		return -ENODEV;
> -	if (!intval && test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
> -		dasd_put_device(base);
> -		return -EROFS;
> -	}
> -	set_disk_ro(bdev->bd_disk, intval);


While testing this patch I just noticed that when I set a device readonly this is
not going to be passed on to the partitions on this device any longer.

This is caused by the removed call to set_disk_ro().

Is this intentional or was this removed by accident?

> -	rc = dasd_set_feature(base->cdev, DASD_FEATURE_READONLY, intval);
> +	if (!ro && test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
> +		rc = -EROFS;
> +	else
> +		rc = dasd_set_feature(base->cdev, DASD_FEATURE_READONLY, ro);
>  	dasd_put_device(base);
>  	return rc;
>  }
> @@ -633,9 +627,6 @@ int dasd_ioctl(struct block_device *bdev, fmode_t mode,
>  	case BIODASDPRRST:
>  		rc = dasd_ioctl_reset_profile(block);
>  		break;
> -	case BLKROSET:
> -		rc = dasd_ioctl_set_ro(bdev, argp);
> -		break;
>  	case DASDAPIVER:
>  		rc = dasd_ioctl_api_version(argp);
>  		break;
> -- 
> 2.28.0
>
Christoph Hellwig Nov. 6, 2020, 2:02 p.m. UTC | #2 
On Thu, Nov 05, 2020 at 09:56:47PM +0100, Stefan Haberland wrote:
> > +	/* do not manipulate hardware state for partitions */
> >  	if (bdev_is_partition(bdev))
> > -		// ro setting is not allowed for partitions
> > -		return -EINVAL;
> > -	if (get_user(intval, (int __user *)argp))
> > -		return -EFAULT;
> > +		return 0;
> > +
> >  	base = dasd_device_from_gendisk(bdev->bd_disk);
> >  	if (!base)
> >  		return -ENODEV;
> > -	if (!intval && test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
> > -		dasd_put_device(base);
> > -		return -EROFS;
> > -	}
> > -	set_disk_ro(bdev->bd_disk, intval);
> 
> 
> While testing this patch I just noticed that when I set a device readonly this is
> not going to be passed on to the partitions on this device any longer.
> 
> This is caused by the removed call to set_disk_ro().
> 
> Is this intentional or was this removed by accident?

It was unintentionally intentional :)

The generic code used already by almost all drivers in mainline only
calls set_device_ro from blkdev_roset, that is it only sets the main
device read-only.  dasd was the outlier here, and I didn't notice it
actually called set_disk_ro instead of set_device_ro.   That being
said I think setting all the partitions read-only as well when the
full device is set read-only makes perfect sense.  I'm just a little
worried it could cause regressions.  Let me prepare a follow on patch
on top of the series that switches to that behavior.
Stefan Haberland Nov. 6, 2020, 4:08 p.m. UTC | #3 
Christoph Hellwig <hch@lst.de> schrieb am Fri, 06. Nov 15:02:
> On Thu, Nov 05, 2020 at 09:56:47PM +0100, Stefan Haberland wrote:
> > > +	/* do not manipulate hardware state for partitions */
> > >  	if (bdev_is_partition(bdev))
> > > -		// ro setting is not allowed for partitions
> > > -		return -EINVAL;
> > > -	if (get_user(intval, (int __user *)argp))
> > > -		return -EFAULT;
> > > +		return 0;
> > > +
> > >  	base = dasd_device_from_gendisk(bdev->bd_disk);
> > >  	if (!base)
> > >  		return -ENODEV;
> > > -	if (!intval && test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
> > > -		dasd_put_device(base);
> > > -		return -EROFS;
> > > -	}
> > > -	set_disk_ro(bdev->bd_disk, intval);
> > 
> > 
> > While testing this patch I just noticed that when I set a device readonly this is
> > not going to be passed on to the partitions on this device any longer.
> > 
> > This is caused by the removed call to set_disk_ro().
> > 
> > Is this intentional or was this removed by accident?
> 
> It was unintentionally intentional :)
> 
> The generic code used already by almost all drivers in mainline only
> calls set_device_ro from blkdev_roset, that is it only sets the main
> device read-only.  dasd was the outlier here, and I didn't notice it
> actually called set_disk_ro instead of set_device_ro.   That being
> said I think setting all the partitions read-only as well when the
> full device is set read-only makes perfect sense.  I'm just a little
> worried it could cause regressions.  Let me prepare a follow on patch
> on top of the series that switches to that behavior.

Makes sense.
I am fine with that.

With this in mind:

Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
diff mbox series

Patch

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index eb17fea8075c6f..db24e04ee9781e 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -3394,6 +3394,7 @@  dasd_device_operations = {
 	.ioctl		= dasd_ioctl,
 	.compat_ioctl	= dasd_ioctl,
 	.getgeo		= dasd_getgeo,
+	.set_read_only	= dasd_set_read_only,
 };
 
 /*******************************************************************************
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index fa552f9f166671..c59a0d63b506e6 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -844,7 +844,8 @@  int dasd_scan_partitions(struct dasd_block *);
 void dasd_destroy_partitions(struct dasd_block *);
 
 /* externals in dasd_ioctl.c */
-int  dasd_ioctl(struct block_device *, fmode_t, unsigned int, unsigned long);
+int dasd_ioctl(struct block_device *, fmode_t, unsigned int, unsigned long);
+int dasd_set_read_only(struct block_device *bdev, bool ro);
 
 /* externals in dasd_proc.c */
 int dasd_proc_init(void);
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index cb6427fb9f3d16..3359559517bfcf 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -532,28 +532,22 @@  static int dasd_ioctl_information(struct dasd_block *block, void __user *argp,
 /*
  * Set read only
  */
-static int
-dasd_ioctl_set_ro(struct block_device *bdev, void __user *argp)
+int dasd_set_read_only(struct block_device *bdev, bool ro)
 {
 	struct dasd_device *base;
-	int intval, rc;
+	int rc;
 
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
+	/* do not manipulate hardware state for partitions */
 	if (bdev_is_partition(bdev))
-		// ro setting is not allowed for partitions
-		return -EINVAL;
-	if (get_user(intval, (int __user *)argp))
-		return -EFAULT;
+		return 0;
+
 	base = dasd_device_from_gendisk(bdev->bd_disk);
 	if (!base)
 		return -ENODEV;
-	if (!intval && test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
-		dasd_put_device(base);
-		return -EROFS;
-	}
-	set_disk_ro(bdev->bd_disk, intval);
-	rc = dasd_set_feature(base->cdev, DASD_FEATURE_READONLY, intval);
+	if (!ro && test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
+		rc = -EROFS;
+	else
+		rc = dasd_set_feature(base->cdev, DASD_FEATURE_READONLY, ro);
 	dasd_put_device(base);
 	return rc;
 }
@@ -633,9 +627,6 @@  int dasd_ioctl(struct block_device *bdev, fmode_t mode,
 	case BIODASDPRRST:
 		rc = dasd_ioctl_reset_profile(block);
 		break;
-	case BLKROSET:
-		rc = dasd_ioctl_set_ro(bdev, argp);
-		break;
 	case DASDAPIVER:
 		rc = dasd_ioctl_api_version(argp);
 		break;