Re: [PATCH v6 09/10] xfs: add minimum file size filtering to eofblocks scan

[Dave Chinner <david@fromorbit.com>]

On Tue, Nov 06, 2012 at 09:50:46AM -0500, Brian Foster wrote:
> Support minimum file size filtering in the eofblocks scan. The
> caller must set the XFS_EOF_FLAGS_MINFILESIZE flags bit and minimum
> file size value in bytes.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> ---
>  fs/xfs/xfs_fs.h     |    6 ++++--
>  fs/xfs/xfs_icache.c |   11 +++++++++--
>  2 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/xfs_fs.h b/fs/xfs/xfs_fs.h
> index 88eb1bc..082b743 100644
> --- a/fs/xfs/xfs_fs.h
> +++ b/fs/xfs/xfs_fs.h
> @@ -348,7 +348,8 @@ struct xfs_eofblocks {
>  	uid_t		eof_uid;
>  	gid_t		eof_gid;
>  	prid_t		eof_prid;
> -	__u32		pad[27];
> +	__u64           eof_min_file_size;
> +	__u32		pad[25];

And that's an exact example of why you should pad out to 8 byte
boundaries like I suggested earlier ;)

What this ends up with is:

	prid		eof_prid;
	<implicit, arch dependent 4 byte hole>
	__u64		eof_min_file_size;
	__32		pad[25];

What you should have is something like:

	prid		eof_prid;
	__u32		pad32;
	__u64		eof_min_file_size;
	__u64		pad64[12];

You should check the way the compiler sees the user visible
structures with pahole - it shows up problems like this in an
obvious manner ;)

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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