From: Dave Chinner <david@fromorbit.com>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: 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: Re: [PATCH 3/3] RFC: dax: dax_prepare_freeze
Date: Tue, 24 Mar 2015 09:40:47 +1100 [thread overview]
Message-ID: <20150323224047.GQ28621@dastard> (raw)
In-Reply-To: <55100D10.6090902@plexistor.com>
On Mon, Mar 23, 2015 at 02:54:40PM +0200, Boaz Harrosh wrote:
> From: Boaz Harrosh <boaz@plexistor.com>
>
> When freezing an FS, we must write protect all IS_DAX()
> inodes that have an mmap mapping on an inode. Otherwise
> application will be able to modify previously faulted-in
> file pages.
All you need to do is lock out page faults once the page is clean;
that's what the sb_start_pagefault() calls are for in the page fault
path - they catch write faults and block them until the filesystem
is unfrozen. Hence I'm not sure why this would be necessary if you
are catching write faults in .pfn_mkwrite....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: 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: Re: [PATCH 3/3] RFC: dax: dax_prepare_freeze
Date: Tue, 24 Mar 2015 09:40:47 +1100 [thread overview]
Message-ID: <20150323224047.GQ28621@dastard> (raw)
In-Reply-To: <55100D10.6090902@plexistor.com>
On Mon, Mar 23, 2015 at 02:54:40PM +0200, Boaz Harrosh wrote:
> From: Boaz Harrosh <boaz@plexistor.com>
>
> When freezing an FS, we must write protect all IS_DAX()
> inodes that have an mmap mapping on an inode. Otherwise
> application will be able to modify previously faulted-in
> file pages.
All you need to do is lock out page faults once the page is clean;
that's what the sb_start_pagefault() calls are for in the page fault
path - they catch write faults and block them until the filesystem
is unfrozen. Hence I'm not sure why this would be necessary if you
are catching write faults in .pfn_mkwrite....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
--
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next prev parent reply other threads:[~2015-03-23 22:40 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 12:47 [PATCH 0/3 v3] dax: Fix mmap-write not updating c/mtime Boaz Harrosh
2015-03-23 12:47 ` Boaz Harrosh
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 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 [this message]
2015-03-23 22:40 ` Dave Chinner
2015-03-24 6:14 ` Boaz Harrosh
2015-03-24 6:14 ` Boaz Harrosh
2015-03-25 2:22 ` Dave Chinner
2015-03-25 2:22 ` Dave Chinner
2015-03-25 8:10 ` Boaz Harrosh
2015-03-25 9:29 ` Dave Chinner
2015-03-25 9:29 ` Dave Chinner
2015-03-25 10:19 ` Boaz Harrosh
2015-03-25 10:19 ` Boaz Harrosh
2015-03-25 20:00 ` Dave Chinner
2015-03-25 20:00 ` Dave Chinner
2015-03-26 8:02 ` Boaz Harrosh
2015-03-26 20:58 ` Dave Chinner
2015-03-26 20:58 ` Dave Chinner
2015-03-24 12:37 ` Boaz Harrosh
2015-03-24 12:37 ` Boaz Harrosh
2015-03-25 2:26 ` Dave Chinner
2015-03-25 2:26 ` Dave Chinner
2015-03-25 8:31 ` Boaz Harrosh
2015-03-25 8:31 ` Boaz Harrosh
2015-03-25 9:41 ` Dave Chinner
2015-03-25 9:41 ` Dave Chinner
2015-03-25 10:40 ` Boaz Harrosh
2015-03-25 10:40 ` Boaz Harrosh
2015-03-25 20:05 ` Dave Chinner
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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