From mboxrd@z Thu Jan  1 00:00:00 1970
From: Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH 1/3] fs: Introduce new flag FALLOC_FL_COLLAPSE_RANGE
Date: Wed, 31 Jul 2013 18:01:54 -0400
Message-ID: <20130731220154.GA11378@thunk.org>
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Cc: adilger.kernel@dilger.ca, bpm@sgi.com, elder@kernel.org,
	hch@infradead.org, david@fromorbit.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
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	Namjae Jeon <namjae.jeon@samsung.com>
To: Namjae Jeon <linkinjeon@gmail.com>
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Have you considered what happens if you have a 10 megabyte file, of
which the first 5 megs are mmap'ed into a userspace process.

Now suppose you call COLLAPASE_RANGE on a one megabyte range starting
at offset 1024k from the beginning of the file.

Does the right thing happen to the mmap'ed region in memory?

Cheers,

					- Ted