Re: [PATCH] possible bug in quota format v2 support

[Smets Jan]

On 2005-03-31 16:21:55 (+0200), Jan Kara <jack@xxxxxxx> wrote:
>   Hello,
> 
> > I'm afraid that there is a bug in quota format v2 delete qentry.
> > (The root block shouldn't be put into free blk list even if there isn't
> > any entry in quota file, right?)
> > 
> > This one line patch may fix it.
>   Such case should not actually occur in normal operation but I agree
> that with your patch the code will handle errors more gracefuly. Your
> patch seems to have wrapped lines and substituted tabs for spaces
> (please try to persuade your mail agent not to wrap lines and substitute
> tabs next time or just send the patch as an attachment) so I rediffed it
> - the result is attached. Andrew please apply the attached patch.
> 
> 					Thanks for spotting it
> 								Honza
> 						
> -- 
> Jan Kara <jack@xxxxxxx>
> SuSE CR Labs

> Don't put root block of quota tree to the free list (when quota file is completely
> empty). That should not actually happen anyway (somebody should get accounted for
> the filesystem root and so quota file should never be empty) but better prevent it
> here than solve magical quota file corruption...
> 
> From: Niu YaWei <niu@xxxxxxxxxxxxx>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> 
> diff -rupX /home/jack/.kerndiffexclude linux-2.6.11/fs/quota_v2.c linux-2.6.11-v2fix/fs/quota_v2.c
> --- linux-2.6.11/fs/quota_v2.c	2005-03-03 18:58:30.000000000 +0100
> +++ linux-2.6.11-v2fix/fs/quota_v2.c	2005-03-31 15:51:51.000000000 +0200
> @@ -503,7 +503,8 @@ static int remove_tree(struct dquot *dqu
>  		int i;
>  		ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
>  		for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);	/* Block got empty? */
> -		if (i == V2_DQBLKSIZE) {
> +		/* Don't put the root block into the free block list */
> +		if (i == V2_DQBLKSIZE && *blk != V2_DQTREEOFF) {
>  			put_free_dqblk(sb, type, buf, *blk);
>  			*blk = 0;
>  		}

Well done Jan :-) 

I've posted an update of my problem with the quotaoff oops:

http://bugme.osdl.org/show_bug.cgi?id=2698

The BUG is at fs/dquot.c:425 

Thanks again.


-- 
Smets Jan
jan@xxxxxxxx

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