Re: [PATCH V2] xfs_repair: print superblock offsets and why they can't be verified

[Eric Sandeen <sandeen@sandeen.net>]

KELEMEN Peter wrote:
> Eric has pointed out that verify_set_primary_sb() will either
> return 1 or XR_INSUFF_SEC_SB.  Move the check lower into
> verify_set_primary_sb() by checking the return value of
> verify_sb().  Example output:
> 
> found candidate secondary superblock...
> verifying sb at 31249334272: bad magic number (1)
> verifying sb at 62498668544: bad magic number (1)
> verifying sb at 93748002816: bad magic number (1)
> verifying sb at 124997337088: bad magic number (1)
> unable to verify superblock, continuing...
> 

This looks better :)  You may want to add even more info...

while it's just searching block by block, if it finds a candidate, I'd
print the sector offset for that candidate (your first output line).

And rather than "verifying sb at..." you might do something like
"comparing to sb N at offset X":

+	} else {
+		do_warn("comparing with sb %d at sector %Lu failed: %s (%d)\n",
+			agno, off, err_string(reason), reason);

because at this point it's using the geometry of the candidate sb to see
if it can be used to find enough other valid sb's....

-Eric


> Signed-off-by: KELEMEN Peter <Peter.Kelemen@cern.ch>
> 
> Index: xfsprogs/repair/sb.c
> ===================================================================
> RCS file: /cvs/xfs-cmds/xfsprogs/repair/sb.c,v
> retrieving revision 1.22
> diff -u -u -r1.22 sb.c
> --- xfsprogs/repair/sb.c	8 Sep 2008 06:18:43 -0000	1.22
> +++ xfsprogs/repair/sb.c	22 Oct 2008 23:17:27 -0000
> @@ -683,6 +683,7 @@
>  	int		num_ok;
>  	int		retval;
>  	int		round;
> +	int		reason;	/* why the sb check failed */
>  
>  	/*
>  	 * select the number of secondaries to try for
> @@ -727,7 +728,7 @@
>  				goto out;
>  			}
>  
> -			if (verify_sb(sb, 0) == XR_OK)  {
> +			if ((reason = verify_sb(sb, 0)) == XR_OK)  {
>  				/*
>  				 * save away geometry info.
>  				 * don't bother checking the sb
> @@ -740,6 +741,9 @@
>  				get_sb_geometry(&geo, sb);
>  				list = add_geo(list, &geo, agno);
>  				num_ok++;
> +			} else {
> +				do_warn("verifying sb at %Lu: %s (%d)\n",
> +					off, err_string(reason), reason);
>  			}
>  		}
>  	}
> 
>