From: Matthew Wilcox <willy@linux.intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>,
Jens Axboe <axboe@kernel.dk>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux ACPI <linux-acpi@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 14/15] libnvdimm: support read-only btt backing devices
Date: Tue, 23 Jun 2015 15:30:43 -0400 [thread overview]
Message-ID: <20150623193043.GE1971@linux.intel.com> (raw)
In-Reply-To: <20150622063028.GA30434@lst.de>
On Mon, Jun 22, 2015 at 08:30:28AM +0200, Christoph Hellwig wrote:
> > Good to hear that we don't need BTT for XFS v5, can we make the
> > guarantee for all filesystems that may want to support DAX? I still
> > think stacking is a natural fit for this problem.
>
> I can't make any guarantees, especially not without verification. But
> if correctly implemented any filesystems that does out of place metadata
> writes (and that includes a traditional log) and uses checksum to ensure
> the integrity of these updates it should be fine. You'd still have
> the issue of sector atomicy of file I/O though.
Is ext4 one of the filesystems that copes with torn updates to the log?
I see there's a checksum in the tail of at least some blocks, but I'd
like someone who understands ext4 to reassure me that it also doesn't
need the ability to put its log on a BTT.
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Wilcox <willy@linux.intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>,
Jens Axboe <axboe@kernel.dk>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux ACPI <linux-acpi@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 14/15] libnvdimm: support read-only btt backing devices
Date: Tue, 23 Jun 2015 15:30:43 -0400 [thread overview]
Message-ID: <20150623193043.GE1971@linux.intel.com> (raw)
In-Reply-To: <20150622063028.GA30434@lst.de>
On Mon, Jun 22, 2015 at 08:30:28AM +0200, Christoph Hellwig wrote:
> > Good to hear that we don't need BTT for XFS v5, can we make the
> > guarantee for all filesystems that may want to support DAX? I still
> > think stacking is a natural fit for this problem.
>
> I can't make any guarantees, especially not without verification. But
> if correctly implemented any filesystems that does out of place metadata
> writes (and that includes a traditional log) and uses checksum to ensure
> the integrity of these updates it should be fine. You'd still have
> the issue of sector atomicy of file I/O though.
Is ext4 one of the filesystems that copes with torn updates to the log?
I see there's a checksum in the tail of at least some blocks, but I'd
like someone who understands ext4 to reassure me that it also doesn't
need the ability to put its log on a BTT.
next prev parent reply other threads:[~2015-06-23 19:30 UTC|newest]
Thread overview: 164+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-17 23:54 [PATCH 00/15] libnvdimm: ->rw_bytes(), BLK-mode, unit tests, and misc features Dan Williams
2015-06-17 23:54 ` Dan Williams
2015-06-17 23:54 ` [PATCH 01/15] block: introduce an ->rw_bytes() block device operation Dan Williams
2015-06-17 23:54 ` Dan Williams
2015-06-18 19:25 ` Dan Williams
2015-06-18 19:25 ` Dan Williams
2015-06-17 23:54 ` [PATCH 02/15] libnvdimm: infrastructure for btt devices Dan Williams
2015-06-17 23:54 ` Dan Williams
2015-06-22 16:34 ` Christoph Hellwig
2015-06-22 16:34 ` Christoph Hellwig
2015-06-22 16:48 ` Dan Williams
2015-06-22 16:48 ` Dan Williams
2015-06-22 16:48 ` Christoph Hellwig
2015-06-22 16:48 ` Christoph Hellwig
2015-06-22 16:48 ` Christoph Hellwig
2015-06-22 18:32 ` Jeff Moyer
2015-06-22 18:32 ` Jeff Moyer
2015-06-22 18:32 ` Jeff Moyer
2015-06-22 19:02 ` Dan Williams
2015-06-22 19:02 ` Dan Williams
2015-06-22 19:02 ` Dan Williams
2015-06-22 19:09 ` Jeff Moyer
2015-06-22 19:09 ` Jeff Moyer
2015-06-22 19:09 ` Jeff Moyer
2015-06-23 10:20 ` Christoph Hellwig
2015-06-23 10:19 ` Christoph Hellwig
2015-06-23 15:19 ` Dan Williams
2015-06-23 20:33 ` Dan Williams
2015-06-24 12:10 ` Christoph Hellwig
2015-06-23 10:10 ` Christoph Hellwig
2015-06-17 23:55 ` [PATCH 03/15] nd_btt: atomic sector updates Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-21 10:03 ` Christoph Hellwig
2015-06-21 10:03 ` Christoph Hellwig
2015-06-21 10:03 ` Christoph Hellwig
2015-06-21 16:31 ` Dan Williams
2015-06-21 16:31 ` Dan Williams
2015-06-17 23:55 ` [PATCH 04/15] libnvdimm, nfit, nd_blk: driver for BLK-mode access persistent memory Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-21 10:05 ` Christoph Hellwig
2015-06-21 10:05 ` Christoph Hellwig
2015-06-21 10:05 ` Christoph Hellwig
2015-06-21 13:31 ` Dan Williams
2015-06-21 13:31 ` Dan Williams
2015-06-21 13:56 ` Christoph Hellwig
2015-06-21 13:56 ` Christoph Hellwig
2015-06-21 13:56 ` Christoph Hellwig
2015-06-21 14:39 ` Dan Williams
2015-06-21 14:39 ` Dan Williams
2015-06-21 14:39 ` Dan Williams
2015-06-17 23:55 ` [PATCH 05/15] tools/testing/nvdimm: libnvdimm unit test infrastructure Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-17 23:55 ` [PATCH 06/15] libnvdimm: Non-Volatile Devices Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-17 23:55 ` [PATCH 07/15] fs/block_dev.c: skip rw_page if bdev has integrity Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-17 23:55 ` [PATCH 08/15] libnvdimm, btt: add support for blk integrity Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-17 23:55 ` [PATCH 09/15] libnvdimm, blk: " Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-17 23:55 ` [PATCH 10/15] libnvdimm: fix up max_hw_sectors Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-21 10:08 ` Christoph Hellwig
2015-06-21 10:08 ` Christoph Hellwig
2015-06-21 10:08 ` Christoph Hellwig
2015-06-21 13:28 ` Dan Williams
2015-06-21 13:28 ` Dan Williams
2015-06-17 23:55 ` [PATCH 11/15] libnvdimm: pmem, blk, and btt make_request cleanups Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-21 10:10 ` Christoph Hellwig
2015-06-21 10:10 ` Christoph Hellwig
2015-06-21 13:26 ` Dan Williams
2015-06-21 13:26 ` Dan Williams
2015-06-21 13:26 ` Dan Williams
2015-06-17 23:55 ` [PATCH 12/15] libnvdimm: enable iostat Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-19 8:34 ` Christoph Hellwig
2015-06-19 8:34 ` Christoph Hellwig
2015-06-19 9:02 ` Dan Williams
2015-06-19 9:02 ` Dan Williams
2015-06-21 10:11 ` Christoph Hellwig
2015-06-21 10:11 ` Christoph Hellwig
2015-06-21 13:22 ` Dan Williams
2015-06-21 13:22 ` Dan Williams
2015-06-21 13:22 ` Dan Williams
2015-06-17 23:55 ` [PATCH 13/15] libnvdimm: flag libnvdimm block devices as non-rotational Dan Williams
2015-06-17 23:55 ` Dan Williams
2015-06-17 23:56 ` [PATCH 14/15] libnvdimm: support read-only btt backing devices Dan Williams
2015-06-17 23:56 ` Dan Williams
2015-06-18 22:55 ` Vishal Verma
2015-06-18 22:55 ` Vishal Verma
2015-06-21 10:13 ` Christoph Hellwig
2015-06-21 10:13 ` Christoph Hellwig
2015-06-21 13:21 ` Dan Williams
2015-06-21 13:21 ` Dan Williams
2015-06-21 13:21 ` Dan Williams
2015-06-21 13:54 ` Christoph Hellwig
2015-06-21 13:54 ` Christoph Hellwig
2015-06-21 13:54 ` Christoph Hellwig
2015-06-21 15:11 ` Dan Williams
2015-06-21 15:11 ` Dan Williams
2015-06-22 6:30 ` Christoph Hellwig
2015-06-22 6:30 ` Christoph Hellwig
2015-06-22 6:30 ` Christoph Hellwig
2015-06-22 7:17 ` Dan Williams
2015-06-22 7:17 ` Dan Williams
2015-06-22 7:17 ` Dan Williams
2015-06-22 7:28 ` Christoph Hellwig
2015-06-22 7:28 ` Christoph Hellwig
2015-06-22 7:28 ` Christoph Hellwig
2015-06-22 7:39 ` Dan Williams
2015-06-22 7:39 ` Dan Williams
2015-06-22 7:39 ` Dan Williams
2015-06-22 15:02 ` Jeff Moyer
2015-06-22 15:02 ` Jeff Moyer
2015-06-22 15:02 ` Jeff Moyer
2015-06-22 15:41 ` Christoph Hellwig
2015-06-22 15:41 ` Christoph Hellwig
2015-06-22 15:41 ` Christoph Hellwig
2015-06-22 16:00 ` Jeff Moyer
2015-06-22 16:00 ` Jeff Moyer
2015-06-22 16:00 ` Jeff Moyer
2015-06-22 16:32 ` Christoph Hellwig
2015-06-22 16:32 ` Christoph Hellwig
2015-06-22 16:32 ` Christoph Hellwig
2015-06-22 16:42 ` Jeff Moyer
2015-06-22 16:42 ` Jeff Moyer
2015-06-22 16:42 ` Jeff Moyer
2015-06-22 16:48 ` Christoph Hellwig
2015-06-22 16:48 ` Christoph Hellwig
2015-06-22 16:48 ` Christoph Hellwig
2015-06-22 18:48 ` Jeff Moyer
2015-06-22 18:48 ` Jeff Moyer
2015-06-22 18:48 ` Jeff Moyer
2015-06-22 19:04 ` Dan Williams
2015-06-22 19:04 ` Dan Williams
2015-06-22 19:11 ` Jeff Moyer
2015-06-22 19:11 ` Jeff Moyer
2015-06-22 19:11 ` Jeff Moyer
2015-06-23 10:10 ` Christoph Hellwig
2015-06-23 10:10 ` Christoph Hellwig
2015-06-22 15:40 ` Christoph Hellwig
2015-06-22 15:40 ` Christoph Hellwig
2015-06-22 15:40 ` Christoph Hellwig
2015-06-22 16:36 ` Dan Williams
2015-06-22 16:36 ` Dan Williams
2015-06-22 16:36 ` Dan Williams
2015-06-22 16:45 ` Christoph Hellwig
2015-06-22 16:45 ` Christoph Hellwig
2015-06-22 16:45 ` Christoph Hellwig
2015-06-22 16:54 ` Dan Williams
2015-06-22 16:54 ` Dan Williams
2015-06-22 16:54 ` Dan Williams
2015-06-22 16:57 ` Christoph Hellwig
2015-06-22 16:57 ` Christoph Hellwig
2015-06-22 16:59 ` Dan Williams
2015-06-22 16:59 ` Dan Williams
2015-06-22 16:59 ` Dan Williams
2015-06-23 19:30 ` Matthew Wilcox [this message]
2015-06-23 19:30 ` Matthew Wilcox
2015-06-24 12:11 ` Christoph Hellwig
2015-06-24 12:11 ` Christoph Hellwig
2015-06-17 23:56 ` [PATCH 15/15] libnvdimm, nfit: handle acpi_nfit_memory_map flags Dan Williams
2015-06-17 23:56 ` Dan Williams
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