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Date: Mon, 7 Apr 2008 11:17:19 +0200
From: Jens Axboe <jens.axboe@oracle.com>
To: =?iso-8859-1?Q?J=F6rn?= Engel <joern@logfs.org>
Subject: Re: [patch 0/15] LogFS take five
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On Mon, Apr 07 2008, Jörn Engel wrote:
> On Mon, 7 April 2008 10:28:41 +0200, Jens Axboe wrote:
> > > 
> > >  fs/block_dev.c |    2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > --- linux-2.6.24logfs/fs/block_dev.c~blockdev_nofs	2008-04-07 10:19:08.627413077 +0200
> > > +++ linux-2.6.24logfs/fs/block_dev.c	2008-04-07 10:20:56.927117162 +0200
> > > @@ -586,7 +586,7 @@ struct block_device *bdget(dev_t dev)
> > >  		inode->i_rdev = dev;
> > >  		inode->i_bdev = bdev;
> > >  		inode->i_data.a_ops = &def_blk_aops;
> > > -		mapping_set_gfp_mask(&inode->i_data, GFP_USER);
> > > +		mapping_set_gfp_mask(&inode->i_data, GFP_USER & ~__GFP_FS);
> > >  		inode->i_data.backing_dev_info = &default_backing_dev_info;
> > >  		spin_lock(&bdev_lock);
> > >  		list_add(&bdev->bd_list, &all_bdevs);
> > 
> > It's not the right fix, generally GFP_FS is fine here. So do that in
> > logfs when you cannot traverse back into the fs, eg
> > 
> >         mapping_gfp_mask(mapping) & ~__GFP_FS;
> > 
> > locally.
> 
> 	struct address_space *mapping;
> 
> 	/* Prevent bdev from calling back into fs */
> 	mapping = &logfs_super(sb)->s_bdev->bd_inode->i_data;
> 	mapping_set_gfp_mask(mapping, mapping_gfp_mask(mapping) & ~__GFP_FS);
> 
> bd_inode has an interesting comment:
> 	struct inode *		bd_inode;	/* will die */
> 
> Should I be worried about that?  It seems to predate git history, so
> I'm not too concerned about immediate changes.

I'd just ignore it, it's widely used anyway...

-- 
Jens Axboe