lkml.org 
[lkml]   [1999]   [Nov]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: Ext2 defragmentation
Date
On Wed, 17 Nov 1999 13:14:45 -0500, you wrote:

>
> No, it's not a problem because the backup superblock doesn't need to be
> written to during the course of normal operations. (The critical
> parameters which e2fsck needs to do its thing don't change after the
> filesystem is created; they do change after a resize2fs, though, so some
> care is needed in that case.) So it's just a matter of
>

I see. I guess I was thinking of the case where the fs was suffciently damaged
so that one would have to kickstart e2fsck with a backup superblock location.
Maybe this never works inpractice so it's not worth the trouble.


> I've noticed another anomaly. When mke2fs 1.18 creates a 1.3GB partition, it
> says the first backup superblock is at 32768 not 32769. Is this an
> off-by-one error?
>
> No; for 2k and 4k filesystems, the primary superblock is located at
> offset 1024 of block #0. (Where the first 1k of block #0 is reserved
> for the boot loader). On 1k filesystems, primary superblock is located
> at block #1, and so the block group boundaries are shifted down by 1
> block.
>
> - Ted

Ah, I get it. Thanks for the info.



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:55    [from the cache]
©2003-2011 Jasper Spaans