[Cluster-devel] [GFS2 PATCH] - Fix fstrim boundary conditions

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

Now in the -nmw tree. Thanks,

Steve.

On Wed, 2013-06-19 at 17:03 -0400, Abhijith Das wrote:
> This patch correctly distinguishes two boundary conditions:
> 
> 1. When the given range is entire within the unaccounted space between two rgrps, and
> 2. The range begins beyond the end of the filesystem
> 
> Also fix the unit of the returned value r.len (total trimming) to be in bytes instead of the (incorrect) 512 byte blocks
> 
> With this patch, GFS2 passes multiple iterations of all the relevant xfstests (251, 260, 288) with different fs block sizes.
> 
> Signed-off-by: Abhi Das <adas@redhat.com>
> 
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index 9809156..6931743 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -1288,13 +1288,15 @@ int gfs2_fitrim(struct file *filp, void __user *argp)
>  	minlen = max_t(u64, r.minlen,
>  		       q->limits.discard_granularity) >> bs_shift;
>  
> +	if (end <= start || minlen > sdp->sd_max_rg_data)
> +		return -EINVAL;
> +
>  	rgd = gfs2_blk2rgrpd(sdp, start, 0);
> -	rgd_end = gfs2_blk2rgrpd(sdp, end - 1, 0);
> +	rgd_end = gfs2_blk2rgrpd(sdp, end, 0);
>  
> -	if (end <= start ||
> -	    minlen > sdp->sd_max_rg_data ||
> -	    start > rgd_end->rd_data0 + rgd_end->rd_data)
> -		return -EINVAL;
> +	if ((gfs2_rgrpd_get_first(sdp) == gfs2_rgrpd_get_next(rgd_end))
> +	    && (start > rgd_end->rd_data0 + rgd_end->rd_data))
> +		return -EINVAL; /* start is beyond the end of the fs */
>  
>  	while (1) {
>  
> @@ -1336,7 +1338,7 @@ int gfs2_fitrim(struct file *filp, void __user *argp)
>  	}
>  
>  out:
> -	r.len = trimmed << 9;
> +	r.len = trimmed << bs_shift;
>  	if (copy_to_user(argp, &r, sizeof(r)))
>  		return -EFAULT;
>  
>