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From: Andrew Morton <>
To: "Darrick J. Wong" <>
	fstests <>
Subject: Re: [PATCH RFC 3/2] fstests: check that we can't write to swap files
Date: Thu, 15 Aug 2019 14:26:03 -0700
Message-ID: <> (raw)
In-Reply-To: <20190815163434.GA15186@magnolia>

On Thu, 15 Aug 2019 09:34:34 -0700 "Darrick J. Wong" <> wrote:

> While active, the media backing a swap file is leased to the kernel.
> Userspace has no business writing to it.  Make sure we can't do this.

I don't think this tests the case where a file was already open for
writing and someone does swapon(that file)?

And then does swapoff(that file), when writes should start working again?

Ditto all the above, with s/open/mmap/.

Do we handle (and test!) the case where there's unwritten dirty
pagecache at the time of swapon()?  Ditto pte-dirty MAP_SHARED pages?

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-15 16:05 [PATCH v3 0/2] vfs: make active swap files unwritable Darrick J. Wong
2019-08-15 16:05 ` [PATCH 1/2] mm: set S_SWAPFILE on blockdev swap devices Darrick J. Wong
2019-08-16  6:39   ` Christoph Hellwig
2019-08-15 16:05 ` [PATCH 2/2] vfs: don't allow writes to swap files Darrick J. Wong
2019-08-16  6:41   ` Christoph Hellwig
2019-08-16  6:48     ` Darrick J. Wong
2019-08-16 16:19   ` [PATCH v2 " Darrick J. Wong
2019-08-18  8:39     ` Christoph Hellwig
2019-08-15 16:34 ` [PATCH RFC 3/2] fstests: check that we can't write " Darrick J. Wong
2019-08-15 21:26   ` Andrew Morton [this message]
2019-08-16  2:13     ` Darrick J. Wong
2019-08-17  2:05   ` [PATCH v2 " Darrick J. Wong

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