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

Stefan Haberland
2020-11-05T20:58:00Z

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
>