linux-kernel - Re: [RFH] Partition table recovery

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Message-ID: <46A488EB.2050305@gmail.com>
Date:	Mon, 23 Jul 2007 12:54:35 +0200
From:	Rene Herman <rene.herman@...il.com>
To:	Jan-Benedict Glaw <jbglaw@...-owl.de>
CC:	Theodore Tso <tytso@....edu>, linux-fsdevel@...r.kernel.org,
	Al Boldi <a1426z@...ab.com>, linux-raid@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [RFH] Partition table recovery

On 07/23/2007 10:41 AM, Jan-Benedict Glaw wrote:

> As multibyte on-disk variables, these will need LE/BE conversion.

Indeed, thanks -- has been updated in the version that is attached.

Also fixes a bug that snuck in (failed to add offset to entry->start).

>> struct entry {
>> 	uint8_t flags;
>> 	uint8_t type;
>> 	uint16_t __1;
>> 	uint64_t start;
>> 	uint32_t size;
> 
> Dito.

This can stay for now. The partition table backup would indeed need some 
defined byte-order but it might be "whatever order the filesystem it's 
backed up onto uses". Since it's not directly written to any filesystem for 
now, host order will do currently.

> Looks like a useful program, but you'd definively fix the LE/BE issues.
> If you do that, it'll be able to even run on BE machines, too.

I might disagree with the usefulness. I believe that preferably a backup 
should be made with help from the kernel (if only by walking sysfs) to avoid 
things getting out of sync between kernel and backup program.

(this program largely does the same as the kernel does but even now there's 
already a difference in so far that I didn't bother to de-garbage the 3rd 
and 4th entries in the second level extendeds).

Rene.

View attachment "partbackup.c" of type "text/plain" (4749 bytes)