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Date: Tue, 23 May 2017 12:13:44 +0200
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Eric Biggers <ebiggers3@gmail.com>
Cc: stable@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>,
        Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH 1/2] ext4 crypto: don't let data integrity writebacks
 fail with ENOMEM
Message-ID: <20170523101344.GA28565@kroah.com>
References: <20170522233752.109220-1-ebiggers3@gmail.com>
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On Mon, May 22, 2017 at 04:37:51PM -0700, Eric Biggers wrote:
> From: Theodore Ts'o <tytso@mit.edu>
> 
> commit c9af28fdd44922a6c10c9f8315718408af98e315 upstream.  [Please apply
> to 4.4-stable.  This fixes a bug which has caused problems on both
> Android and Chrome OS, and this fix has already been included in a
> number of ext4 encryption backports.]
> 
> We don't want the writeback triggered from the journal commit (in
> data=writeback mode) to cause the journal to abort due to
> generic_writepages() returning an ENOMEM error.  In addition, if
> fsync() fails with ENOMEM, most applications will probably not do the
> right thing.
> 
> So if we are doing a data integrity sync, and ext4_encrypt() returns
> ENOMEM, we will submit any queued I/O to date, and then retry the
> allocation using GFP_NOFAIL.
> 
> Google-Bug-Id: 27641567
> 
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Thanks for both of these, now queued up.

greg k-h