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Date: Thu, 2 Jul 2015 10:17:54 -0400
From: "Theodore Ts'o" <tytso@mit.edu>
To: Nikolay Borisov <kernel@kyup.com>
Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
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Subject: Re: [PATCH 2/2] ext4: make use of sb_getblk_gfp
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On Thu, Jul 02, 2015 at 09:16:34AM +0300, Nikolay Borisov wrote:
> 
> Just a question that popped to my mind after discussing with a colleague
> - Is GFP_NOFS enough here or should it be GFP_NOIO? Presumably the
> latter is a stronger guarantee that we are not going to hit any
> fs/writeback related code?

GFP_NOFS is fine here; file system code calls the I/O codepaths, but
device driver code doesn't call fs code.  Put another way, if there
are pages that are backed by a block device, which can be cleaned
without going through the FS code paths, it's fine to let that happen
while we are inside file system code.

						- Ted
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