From: Nick Piggin <npiggin@suse.de>
Subject: Re: [patch 5/5] ext2: convert to use the new truncate convention.
Date: Mon, 17 Aug 2009 08:42:16 +0200
Message-ID: <20090817064216.GC9962@wotan.suse.de>
References: <20090816102533.329473921@suse.de> <20090816102856.846088617@suse.de> <20090816201626.GA23048@infradead.org>
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Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>
To: Christoph Hellwig <hch@infradead.org>
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On Sun, Aug 16, 2009 at 04:16:26PM -0400, Christoph Hellwig wrote:
> On Sun, Aug 16, 2009 at 08:25:38PM +1000, npiggin@suse.de wrote:
> > @@ -66,9 +68,10 @@ void ext2_delete_inode (struct inode * i
> >  	mark_inode_dirty(inode);
> >  	ext2_write_inode(inode, inode_needs_sync(inode));
> >  
> > +	/* XXX: where is truncate_inode_pages? */
> >  	inode->i_size = 0;
> >  	if (inode->i_blocks)
> > -		ext2_truncate (inode);
> > +		ext2_truncate_blocks(inode, 0);
> >  	ext2_free_inode (inode);
> 
> At the beginning of the function, just before the diff window.  Because
> this is ->delete_inode we truncate away all pages, down to offset 0.

OK, weird. I thought I couldn't see it when I wrote that :) maybe my
tree was corrupted or I'm stupid.


> > +static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
> > +{
> > +	/*
> > +	 * XXX: it seems like a bug here that we don't allow
> > +	 * IS_APPEND inode to have blocks-past-i_size trimmed off.
> > +	 * review and fix this.
> > +	 */
> > +	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
> > +	    S_ISLNK(inode->i_mode)))
> > +		return -EINVAL;
> > +	if (ext2_inode_is_fast_symlink(inode))
> > +		return -EINVAL;
> > +	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
> > +		return -EPERM;
> > +	__ext2_truncate_blocks(inode, offset);
> 
> Yes, I think the IS_APPEND(inode) || IS_IMMUTABLE(inode) checks should move
> into ext2_setsize.  But let's leave that for a separate patch.

Yeah agreed.

 
> Btw, the above code gives me warnings like this:
> 
> /home/hch/work/linux-2.6/fs/ext2/inode.c: In function
> 'ext2_truncate_blocks':
> /home/hch/work/linux-2.6/fs/ext2/inode.c:1158: warning: 'return' with a
> value, in function returning void
> /home/hch/work/linux-2.6/fs/ext2/inode.c:1160: warning: 'return' with a
> value, in function returning void
> /home/hch/work/linux-2.6/fs/ext2/inode.c:1162: warning: 'return' with a
> value, in function returning void
> 
> because you try to return errors from a function delcared as void.

Hm, sorry. I thought it was in good shape... I'll recheck that I sent
out the correct versions and resend according to feedback from you
and Hugh.

Thanks,
Nick