Re: [PATCH v2 2/3] mm: Update file times when inodes are writtenafter mmaped writes

From: Andy Lutomirski
Date: Sat Dec 22 2012 - 03:43:49 EST


On Sat, Dec 22, 2012 at 12:29 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> NAK, we went through great trouble to get rid of the nasty layering
> violation where the VM called file_update_time directly just a short
> while ago, reintroducing that is a massive step back.
>
> Make sure whatever "solution" for your problem you come up with keeps
> the file update in the filesystem or generic helpers.
>

There's an inode operation ->update_time that is called (if it exists)
in these patches to update the time. Is that insufficient? I could
add a new inode operation ->modified_by_mmap that would be called in
mapping_flush_cmtime if that would be better.

The original version of this patch did the update in ->writepage and
->writepages, but that may have had lock ordering issues. (I wasn't
able to confirm that there was any actual problem.)

--Andy
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