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Date: Wed, 19 Sep 2001 08:07:30 -0400 (EDT)
From: Alexander Viro <viro@math.psu.edu>
To: Andrea Arcangeli <andrea@suse.de>
cc: linux-kernel@vger.kernel.org
Subject: Re: 2.4.10pre11aa1
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> I can add one more into the mix: what the hell had happened in rd.c?
> 
> a) you reintroduced the crap with rd_inodes[]
> b) just try to call ioctl(fd, BLKFLSBUF) twice. Oops...
> c) WTF with acrobatics around initrd_bd_op?  FWIW, initrd has no business
> being a block device and both old and new variants are ugly, but what's
> the point of adding extra tricks?
> d) call ioctl(fd, BLKFLSBUF) and open the thing one more time before
> closing fd.  Watch what happens.  It's broken by design.
> 
> I realize that you had that file modified in your tree, but bloody hell,
> it doesn't mean "ignore any changes that happened in mainline kernel
> without even looking at them".  As for the BLKFLSBUF...  How was it supposed
> to work?


BTW, what's to stop shrink_cache() from picking a page out of ramdisk
pagecache and calling ->writepage() on it?  The thing will immediately
get dirtied again, AFAICS (blkdev_writepage() -> submit_bh() -> ... ->
rd_make_request() -> rd_blkdev_pagecache(WRITE,...) -> SetPageDirty()).

If you get a lot of stuff in ramdisks, things can get rather insteresting...