Re: [PATCH 1/3] ext3/ext4: Factor out disk addressability check

[Joel Becker <Joel.Becker@oracle.com>]

On Mon, Aug 16, 2010 at 09:21:00PM +0200, Jan Kara wrote:
> On Mon 16-08-10 12:13:19, Joel Becker wrote:
> > On Mon, Aug 16, 2010 at 09:44:35AM -0500, Eric Sandeen wrote:
> > > Joel Becker wrote:
> > > > How about:
> > > > 
> > > > 	u64 last_fs_page = last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);
> > > > 
> > > > 	... ||
> > > > 	(last_fs_page > (pgoff_t)(~0ULL))) {
> > > > 
> > > > Is that more readable?
> > > 
> > > To me, yes.  Maybe do similar for last_fs_sector.
> > 
> > 	last_fs_sector would be shifting up, which could wrap a really
> > large last_fs_blocks.  So I'm going to keep the sector_t check as-is.
> > How's this:
> > 
> > >From 8de5cb9164cdc179ba84a07b282a895d0eb794b0 Mon Sep 17 00:00:00 2001
> > >From: Joel Becker <joel.becker@oracle.com>
> > Date: Mon, 16 Aug 2010 12:10:17 -0700
> > Subject: [PATCH] libfs: Fix shift bug in generic_check_addressable()
> > 
> > generic_check_addressable() erroneously shifts pages down by a block
> > factor when it should be shifting up.  To prevent overflow, we shift
> > blocks down to pages.
> > 
> > Signed-off-by: Joel Becker <joel.becker@oracle.com>
>   Looks good.
> Reviewed-by: Jan Kara <jack@suse.cz>

	Ok, I'm going to keep this atop my existing branch, and if it
all shakes out in linux-next for a few days, send it along.

Joel

-- 

"When ideas fail, words come in very handy." 
         - Goethe

Joel Becker
Consulting Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127