Re: [PATCH 2/2] ext4: make use of sb_getblk_gfp

From	Theodore Ts'o <tytso@mit.edu>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/2] ext4: make use of sb_getblk_gfp
Date	2015-07-02 16:20 +0200
Message-ID	<pHNvk-3Pj-27@gated-at.bofh.it> (permalink)
References	<pGXdo-212-3@gated-at.bofh.it> <pGXdo-212-1@gated-at.bofh.it> <pHG0N-7vH-11@gated-at.bofh.it> <pHG0O-7vH-17@gated-at.bofh.it>
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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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Re: [PATCH 2/2] ext4: make use of sb_getblk_gfp Theodore Ts'o <tytso@mit.edu> - 2015-07-02 16:20 +0200

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