svn commit: r329265 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[John Baldwin]

On Wednesday, February 14, 2018 03:49:31 PM Alan Somers wrote:
> Author: asomers
> Date: Wed Feb 14 15:49:31 2018
> New Revision: 329265
> URL: https://svnweb.freebsd.org/changeset/base/329265
> 
> Log:
>   Implement .vop_pathconf and .vop_getacl for the .zfs ctldir
>   
>   zfsctl_common_pathconf will report all the same variables that regular ZFS
>   volumes report. zfsctl_common_getacl will report an ACL equivalent to 555,
>   except that you can't read xattrs or edit attributes.
>   
>   Fixes a bug where "ls .zfs" will occasionally print something like:
>   ls: .zfs/.: Operation not supported
>   
>   PR:		225793
>   Reviewed by:	avg
>   MFC after:	3 weeks
>   Sponsored by:	Spectra Logic Corp
>   Differential Revision:	https://reviews.freebsd.org/D14365
> 
> Modified:
>   head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
> 
> Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
> ==============================================================================
> --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c	Wed Feb 14 15:40:13 2018	(r329264)
> +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c	Wed Feb 14 15:49:31 2018	(r329265)
> @@ -80,6 +80,10 @@
>  
>  #include "zfs_namecheck.h"
>  
> +/* Common access mode for all virtual directories under the ctldir */
> +const u_short zfsctl_ctldir_mode = S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP |
> +    S_IROTH | S_IXOTH;
> +
>  /*
>   * "Synthetic" filesystem implementation.
>   */
> @@ -496,8 +500,7 @@ zfsctl_common_getattr(vnode_t *vp, vattr_t *vap)
>  	vap->va_nblocks = 0;
>  	vap->va_seq = 0;
>  	vn_fsid(vp, vap);
> -	vap->va_mode = S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP |
> -	    S_IROTH | S_IXOTH;
> +	vap->va_mode = zfsctl_ctldir_mode;
>  	vap->va_type = VDIR;
>  	/*
>  	 * We live in the now (for atime).
> @@ -724,6 +727,87 @@ zfsctl_root_vptocnp(struct vop_vptocnp_args *ap)
>  	return (0);
>  }
>  
> +static int
> +zfsctl_common_pathconf(ap)
> +	struct vop_pathconf_args /* {
> +		struct vnode *a_vp;
> +		int a_name;
> +		int *a_retval;
> +	} */ *ap;
> +{
> +	/*
> +	 * We care about ACL variables so that user land utilities like ls
> +	 * can display them correctly.  Since the ctldir's st_dev is set to be
> +	 * the same as the parent dataset, we must support all variables that
> +	 * it supports.
> +	 */
> +	switch (ap->a_name) {
> +	case _PC_LINK_MAX:
> +		*ap->a_retval = INT_MAX;
> +		return (0);

On HEAD this should probably match the existing ZFS pathconf
(min(LONG_MAX, ZFS_LINK_MAX IIRC), though if these directories can only
ever have a link count of 2 (which seems true from zfsctl_common_getattr())
then it would be fine to return '2' here instead.  For stable you'd have to
restrict it to LINK_MAX if you don't use '2'.

Also, you should call vfs_stdpathconf() in the default: case.

-- 
John Baldwin