[PATCH 23/24] filelock: default to returning -EINVAL when ->setlease operation is NULL

[Jan Kara]

On Thu 08-01-26 12:13:18, Jeff Layton wrote:
> Now that most filesystems where we expect to need lease support have
> their ->setlease() operations explicitly set, change kernel_setlease()
> to return -EINVAL when the setlease is a NULL pointer.
> 
> Also update the Documentation/ with info about this change.
> 
> Signed-off-by: Jeff Layton <jlayton at kernel.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack at suse.cz>

								Honza

> ---
>  Documentation/filesystems/porting.rst | 9 +++++++++
>  Documentation/filesystems/vfs.rst     | 9 ++++++---
>  fs/locks.c                            | 3 +--
>  3 files changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
> index 3397937ed838e5e7dfacc6379a9d71481cc30914..c0f7103628ab5ed70d142a5c7f6d95ca4734c741 100644
> --- a/Documentation/filesystems/porting.rst
> +++ b/Documentation/filesystems/porting.rst
> @@ -1334,3 +1334,12 @@ end_creating() and the parent will be unlocked precisely when necessary.
>  
>  kill_litter_super() is gone; convert to DCACHE_PERSISTENT use (as all
>  in-tree filesystems have done).
> +
> +---
> +
> +**mandatory**
> +
> +The ->setlease() file_operation must now be explicitly set in order to provide
> +support for leases. When set to NULL, the kernel will now return -EINVAL to
> +attempts to set a lease. Filesystems that wish to use the kernel-internal lease
> +implementation should set it to generic_setlease().
> diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
> index 670ba66b60e4964927164a57e68adc0edfc681ee..21dc8921dd9ebedeafc4c108de7327f172138b6e 100644
> --- a/Documentation/filesystems/vfs.rst
> +++ b/Documentation/filesystems/vfs.rst
> @@ -1180,9 +1180,12 @@ otherwise noted.
>  	method is used by the splice(2) system call
>  
>  ``setlease``
> -	called by the VFS to set or release a file lock lease.  setlease
> -	implementations should call generic_setlease to record or remove
> -	the lease in the inode after setting it.
> +	called by the VFS to set or release a file lock lease.  Local
> +	filesystems that wish to use the kernel-internal lease implementation
> +	should set this to generic_setlease(). Other setlease implementations
> +	should call generic_setlease() to record or remove the lease in the inode
> +	after setting it. When set to NULL, attempts to set or remove a lease will
> +	return -EINVAL.
>  
>  ``fallocate``
>  	called by the VFS to preallocate blocks or punch a hole.
> diff --git a/fs/locks.c b/fs/locks.c
> index e2036aa4bd3734be415296f9157d8f17166878aa..ea38a18f373c2202ba79e8e37125f8d32a0e2d42 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2016,8 +2016,7 @@ kernel_setlease(struct file *filp, int arg, struct file_lease **lease, void **pr
>  		setlease_notifier(arg, *lease);
>  	if (filp->f_op->setlease)
>  		return filp->f_op->setlease(filp, arg, lease, priv);
> -	else
> -		return generic_setlease(filp, arg, lease, priv);
> +	return -EINVAL;
>  }
>  EXPORT_SYMBOL_GPL(kernel_setlease);
>  
> 
> -- 
> 2.52.0
> 
-- 
Jan Kara <jack at suse.com>
SUSE Labs, CR