Re: [PATCH 1/4] xfs: Don't wrap growfs AGFL indexes

[Carlos Maiolino <cmaiolino@redhat.com>]

Looks good to me, feel free to add

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>


On Tue, Apr 05, 2016 at 04:05:07PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Commit 96f859d ("libxfs: pack the agfl header structure so
> XFS_AGFL_SIZE is correct") allowed the freelist to use the empty
> slot at the end of the freelist on 64 bit systems that was not
> being used due to sizeof() rounding up the structure size.
> 
> This has caused versions of xfs_repair prior to 4.5.0 (which also
> has the fix) to report this as a corruption once the filesystem has
> been grown. Older kernels can also have problems (seen from a whacky
> container/vm management environment) mounting filesystems grown on a
> system with a newer kernel than the vm/container it is deployed on.
> 
> To avoid this problem, change the initial free list indexes not to
> wrap across the end of the AGFL, hence avoiding the initialisation
> of agf_fllast to the last index in the AGFL.
> 
> cc: <stable@vger.kernel.org> # 4.4-4.5
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/xfs_fsops.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index ee3aaa0a..ca0d3eb 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -243,8 +243,8 @@ xfs_growfs_data_private(
>  		agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
>  		agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
>  		agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
> -		agf->agf_flfirst = 0;
> -		agf->agf_fllast = cpu_to_be32(XFS_AGFL_SIZE(mp) - 1);
> +		agf->agf_flfirst = cpu_to_be32(1);
> +		agf->agf_fllast = 0;
>  		agf->agf_flcount = 0;
>  		tmpsize = agsize - XFS_PREALLOC_BLOCKS(mp);
>  		agf->agf_freeblks = cpu_to_be32(tmpsize);
> -- 
> 2.7.0
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs

-- 
Carlos

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs