Re: [PATCH 04/10] xfs: expand xfs_fsop_geom

[Dave Chinner <david@fromorbit.com>]

On Mon, Apr 01, 2019 at 10:10:34AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Rename the current (v2-v4) geometry ioctl XFS_IOC_FSGEOMETRY_V2 and
> expand the existing xfs_fsop_geom to reserve empty space for more
> fields.  This means that newly built binaries will pick up the new
> format and existing programs will simply end up in the V2 handler.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

This looks familiar....

Thu, 26 Oct 2017 19:33:19 +1100
[PATCH 11/14] xfs: bump XFS_IOC_FSGEOMETRY to v5 structures

https://patchwork.kernel.org/patch/10027799/

> ---
>  fs/xfs/libxfs/xfs_fs.h |   32 +++++++++++++++++++++++++++++++-
>  fs/xfs/libxfs/xfs_sb.c |    5 +++++
>  fs/xfs/xfs_ioctl.c     |   22 ++++++++++++++++++++--
>  fs/xfs/xfs_ioctl32.c   |    1 +
>  4 files changed, 57 insertions(+), 3 deletions(-)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
> index f3aa59302fef..1dba751cde60 100644
> --- a/fs/xfs/libxfs/xfs_fs.h
> +++ b/fs/xfs/libxfs/xfs_fs.h
> @@ -148,7 +148,34 @@ typedef struct xfs_fsop_geom_v1 {
>  } xfs_fsop_geom_v1_t;
>  
>  /*
> - * Output for XFS_IOC_FSGEOMETRY
> + * Output for XFS_IOC_FSGEOMETRY_V2
> + */
> +typedef struct xfs_fsop_geom_v2 {
> +	__u32		blocksize;	/* filesystem (data) block size */
> +	__u32		rtextsize;	/* realtime extent size		*/
> +	__u32		agblocks;	/* fsblocks in an AG		*/
> +	__u32		agcount;	/* number of allocation groups	*/
> +	__u32		logblocks;	/* fsblocks in the log		*/
> +	__u32		sectsize;	/* (data) sector size, bytes	*/
> +	__u32		inodesize;	/* inode size in bytes		*/
> +	__u32		imaxpct;	/* max allowed inode space(%)	*/
> +	__u64		datablocks;	/* fsblocks in data subvolume	*/
> +	__u64		rtblocks;	/* fsblocks in realtime subvol	*/
> +	__u64		rtextents;	/* rt extents in realtime subvol*/
> +	__u64		logstart;	/* starting fsblock of the log	*/
> +	unsigned char	uuid[16];	/* unique id of the filesystem	*/
> +	__u32		sunit;		/* stripe unit, fsblocks	*/
> +	__u32		swidth;		/* stripe width, fsblocks	*/
> +	__s32		version;	/* structure version		*/
> +	__u32		flags;		/* superblock version flags	*/
> +	__u32		logsectsize;	/* log sector size, bytes	*/
> +	__u32		rtsectsize;	/* realtime sector size, bytes	*/
> +	__u32		dirblocksize;	/* directory block size, bytes	*/
> +	__u32		logsunit;	/* log stripe unit, bytes */
> +} xfs_fsop_geom_v2_t;

That's actually the v4 structurei, not the v2 structure. fsgeom
versions 1-3 used the v1 structure, v4 uses this structure, and v5
uses the current structure. So this (and the renamed ioctl) should
really be name "v4", not "v2".


> +/*
> + * Output for XFS_IOC_FSGEOMETRY (v5)
>   */
>  typedef struct xfs_fsop_geom {
>  	__u32		blocksize;	/* filesystem (data) block size */
> @@ -172,6 +199,7 @@ typedef struct xfs_fsop_geom {
>  	__u32		rtsectsize;	/* realtime sector size, bytes	*/
>  	__u32		dirblocksize;	/* directory block size, bytes	*/
>  	__u32		logsunit;	/* log stripe unit, bytes */
> +	__u64		reserved[18];	/* reserved space */
>  } xfs_fsop_geom_t;
>  
>  /* Output for XFS_FS_COUNTS */
> @@ -189,6 +217,7 @@ typedef struct xfs_fsop_resblks {
>  } xfs_fsop_resblks_t;
>  
>  #define XFS_FSOP_GEOM_VERSION	0
> +#define XFS_FSOP_GEOM_V5	5
>  
>  #define XFS_FSOP_GEOM_FLAGS_ATTR	0x0001	/* attributes in use	*/
>  #define XFS_FSOP_GEOM_FLAGS_NLINK	0x0002	/* 32-bit nlink values	*/
> @@ -620,6 +649,7 @@ struct xfs_scrub_metadata {
>  #define XFS_IOC_FSSETDM_BY_HANDLE    _IOW ('X', 121, struct xfs_fsop_setdm_handlereq)
>  #define XFS_IOC_ATTRLIST_BY_HANDLE   _IOW ('X', 122, struct xfs_fsop_attrlist_handlereq)
>  #define XFS_IOC_ATTRMULTI_BY_HANDLE  _IOW ('X', 123, struct xfs_fsop_attrmulti_handlereq)
> +#define XFS_IOC_FSGEOMETRY_V2	     _IOR ('X', 124, struct xfs_fsop_geom_v2)
>  #define XFS_IOC_FSGEOMETRY	     _IOR ('X', 124, struct xfs_fsop_geom)
                                                ^^^
The identifier for the XFS_IOC_FSGEOMETRY ioctl needs to change
because it's now a new ioctl.


>  #define XFS_IOC_GOINGDOWN	     _IOR ('X', 125, uint32_t)
>  /*	XFS_IOC_GETFSUUID ---------- deprecated 140	 */
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index f0309b74e377..c2ca3a816c41 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -1168,6 +1168,11 @@ xfs_fs_geometry(
>  
>  	geo->logsunit = sbp->sb_logsunit;
>  
> +	if (struct_version < 5)
> +		return 0;
> +
> +	geo->version = XFS_FSOP_GEOM_V5;
> +
>  	return 0;
>  }
>  
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 6ecdbb3af7de..7fd8815633dc 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -801,7 +801,7 @@ xfs_ioc_fsgeometry_v1(
>  }
>  
>  STATIC int
> -xfs_ioc_fsgeometry(
> +xfs_ioc_fsgeometry_v2(
>  	xfs_mount_t		*mp,
>  	void			__user *arg)
>  {
> @@ -812,6 +812,23 @@ xfs_ioc_fsgeometry(
>  	if (error)
>  		return error;
>  
> +	if (copy_to_user(arg, &fsgeo, sizeof(struct xfs_fsop_geom_v2)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
> +STATIC int
> +xfs_ioc_fsgeometry(
> +	struct xfs_mount	*mp,
> +	void			__user *arg)
> +{
> +	struct xfs_fsop_geom	fsgeo;
> +	int			error;
> +
> +	error = xfs_fs_geometry(&mp->m_sb, &fsgeo, 5);
> +	if (error)
> +		return error;
> +
>  	if (copy_to_user(arg, &fsgeo, sizeof(fsgeo)))
>  		return -EFAULT;
>  	return 0;

And I factored all this into a single function, because it's just
boiler plate that can be done with a version switch passed in from
the XFS_IOC_FSGEOMETRY* calls themselves. see the patch I referenced
above....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com