From: Boaz Harrosh <boaz@plexistor.com>
To: Dave Chinner <david@fromorbit.com>,
Matthew Wilcox <matthew.r.wilcox@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Jan Kara <jack@suse.cz>, Hugh Dickins <hughd@google.com>,
Mel Gorman <mgorman@suse.de>,
linux-mm@kvack.org, linux-nvdimm <linux-nvdimm@ml01.01.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Eryu Guan <eguan@redhat.com>
Subject: [PATCH 0/3 v3] dax: Fix mmap-write not updating c/mtime
Date: Mon, 23 Mar 2015 14:47:52 +0200 [thread overview]
Message-ID: <55100B78.501@plexistor.com> (raw)
Hi
[v3]
* I'm re-posting the two DAX patches that fix the mmap-write after read
problem with DAX. (No changes since [v2])
* I'm also posting a 3rd RFC patch to address what Jan said about fs_freeze
and making mapping read-only.
Jan Please review and see if this is what you meant.
[v2]
Jan Kara has pointed out that if we add the
sb_start/end_pagefault pair in the new pfn_mkwrite we
are then fixing another bug where: A user could start
writing to the page while filesystem is frozen.
[v1]
The main problem is that current mm/memory.c will no call us with page_mkwrite
if we do not have an actual page mapping, which is what DAX uses.
The solution presented here introduces a new pfn_mkwrite to solve this problem.
Please see patch-2 for details.
I've been running with this patch for 4 month both HW and VMs with no apparent
danger, but see patch-1 I played it safe.
I am also posting an xfstest 080 that demonstrate this problem, I believe
that also some git operations (can't remember which) suffer from this problem.
Actually Eryu Guan found that this test fails on some other FS as well.
List of patches:
[PATCH 1/3] mm: New pfn_mkwrite same as page_mkwrite for VM_PFNMAP
[PATCH 2/3] dax: use pfn_mkwrite to update c/mtime + freeze
[PATCH 3/3] RFC: dax: dax_prepare_freeze
[PATCH v4] xfstest: generic/080 test that mmap-write updates c/mtime
Please I need that some mm person review the first patch?
Andrew hi
I believe this needs to eventually go through your tree. Please pick it
up when you feel it is ready. I believe the first 2 are ready and fix real
bugs.
Matthew hi
I would love to have your ACK on these patches?
Thanks
Boaz
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next reply other threads:[~2015-03-23 12:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 12:47 Boaz Harrosh [this message]
2015-03-23 12:49 ` [PATCH 1/3] mm: New pfn_mkwrite same as page_mkwrite for VM_PFNMAP Boaz Harrosh
2015-03-23 22:49 ` Andrew Morton
2015-03-23 12:52 ` [PATCH 2/3] dax: use pfn_mkwrite to update c/mtime + freeze protection Boaz Harrosh
2015-03-23 12:54 ` [PATCH 3/3] RFC: dax: dax_prepare_freeze Boaz Harrosh
2015-03-23 22:40 ` Dave Chinner
2015-03-24 6:14 ` Boaz Harrosh
2015-03-25 2:22 ` Dave Chinner
2015-03-25 8:10 ` Boaz Harrosh
2015-03-25 9:29 ` Dave Chinner
2015-03-25 10:19 ` Boaz Harrosh
2015-03-25 20:00 ` Dave Chinner
2015-03-26 8:02 ` Boaz Harrosh
2015-03-26 20:58 ` Dave Chinner
2015-03-24 12:37 ` Boaz Harrosh
2015-03-25 2:26 ` Dave Chinner
2015-03-25 8:31 ` Boaz Harrosh
2015-03-25 9:41 ` Dave Chinner
2015-03-25 10:40 ` Boaz Harrosh
2015-03-25 20:05 ` Dave Chinner
2015-03-23 12:56 ` [PATCH v4] xfstest: generic/080 test that mmap-write updates c/mtime Boaz Harrosh
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