From: Daniel Phillips <daniel@phunq.net> To: Rik van Riel <riel@redhat.com>, Jan Kara <jack@suse.cz> Cc: David Lang <david@lang.hm>, tux3@tux3.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Subject: Re: [FYI] tux3: Core changes Date: Tue, 26 May 2015 14:49:55 -0700 [thread overview] Message-ID: <5564EA83.80108@phunq.net> (raw) In-Reply-To: <5564E76D.7080901@redhat.com> On 05/26/2015 02:36 PM, Rik van Riel wrote: > On 05/26/2015 04:22 PM, Daniel Phillips wrote: >> On 05/26/2015 02:00 AM, Jan Kara wrote: >>> So my opinion is: Don't fork the page if page_count is elevated. You can >>> just wait for the IO if you need stable pages in that case. It's slow but >>> it's safe and it should be pretty rare. Is there any problem with that? >> >> That would be our fallback if anybody discovers a specific case where page >> fork breaks something, which so far has not been demonstrated. >> >> With a known fallback, it is hard to see why we should delay merging over >> that. Perfection has never been a requirement for merging filesystems. On > > However, avoiding data corruption by erring on the side of safety is > a pretty basic requirement. Erring on the side of safety is still an error. As a community we have never been fond of adding code or overhead to fix theoretical bugs. I do not see why we should relax that principle now. We can fix actual bugs, but theoretical bugs are only shapeless specters passing in the night. We should not become frozen in fear of them. >> the contrary, imperfection is a reason for merging, so that the many >> eyeballs effect may prove its value. > > If you skip the page fork when there is an elevated page count, tux3 > should be safe (at least from that aspect). Only do the COW when there > is no "strange" use of the page going on. Then you break the I in ACID. There must be a compelling reason to do that. Regards, Daniel
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From: Daniel Phillips <daniel@phunq.net> To: Rik van Riel <riel@redhat.com>, Jan Kara <jack@suse.cz> Cc: David Lang <david@lang.hm>, tux3@tux3.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Subject: Re: [FYI] tux3: Core changes Date: Tue, 26 May 2015 14:49:55 -0700 [thread overview] Message-ID: <5564EA83.80108@phunq.net> (raw) In-Reply-To: <5564E76D.7080901@redhat.com> On 05/26/2015 02:36 PM, Rik van Riel wrote: > On 05/26/2015 04:22 PM, Daniel Phillips wrote: >> On 05/26/2015 02:00 AM, Jan Kara wrote: >>> So my opinion is: Don't fork the page if page_count is elevated. You can >>> just wait for the IO if you need stable pages in that case. It's slow but >>> it's safe and it should be pretty rare. Is there any problem with that? >> >> That would be our fallback if anybody discovers a specific case where page >> fork breaks something, which so far has not been demonstrated. >> >> With a known fallback, it is hard to see why we should delay merging over >> that. Perfection has never been a requirement for merging filesystems. On > > However, avoiding data corruption by erring on the side of safety is > a pretty basic requirement. Erring on the side of safety is still an error. As a community we have never been fond of adding code or overhead to fix theoretical bugs. I do not see why we should relax that principle now. We can fix actual bugs, but theoretical bugs are only shapeless specters passing in the night. We should not become frozen in fear of them. >> the contrary, imperfection is a reason for merging, so that the many >> eyeballs effect may prove its value. > > If you skip the page fork when there is an elevated page count, tux3 > should be safe (at least from that aspect). Only do the COW when there > is no "strange" use of the page going on. Then you break the I in ACID. There must be a compelling reason to do that. Regards, Daniel
next prev parent reply other threads:[~2015-05-26 21:50 UTC|newest] Thread overview: 211+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-04-28 23:13 Tux3 Report: How fast can we fsync? Daniel Phillips 2015-04-28 23:13 ` Daniel Phillips 2015-04-29 2:21 ` Mike Galbraith 2015-04-29 6:01 ` Daniel Phillips 2015-04-29 6:01 ` Daniel Phillips 2015-04-29 6:20 ` Richard Weinberger 2015-04-29 6:56 ` Daniel Phillips 2015-04-29 6:56 ` Daniel Phillips 2015-04-29 6:33 ` Mike Galbraith 2015-04-29 7:23 ` Daniel Phillips 2015-04-29 7:23 ` Daniel Phillips 2015-04-29 16:42 ` Mike Galbraith 2015-04-29 19:05 ` xfs: does mkfs.xfs require fancy switches to get decent performance? (was Tux3 Report: How fast can we fsync?) Mike Galbraith 2015-04-29 19:20 ` Austin S Hemmelgarn 2015-04-29 21:12 ` Daniel Phillips 2015-04-30 4:40 ` Mike Galbraith 2015-04-30 0:20 ` Dave Chinner 2015-04-30 3:35 ` Mike Galbraith 2015-04-30 9:00 ` Martin Steigerwald 2015-04-30 9:00 ` Martin Steigerwald 2015-04-30 14:57 ` Theodore Ts'o 2015-04-30 15:59 ` Daniel Phillips 2015-04-30 17:59 ` Martin Steigerwald 2015-04-30 11:14 ` Daniel Phillips 2015-04-30 12:07 ` Mike Galbraith 2015-04-30 12:58 ` Daniel Phillips 2015-04-30 12:58 ` Daniel Phillips 2015-04-30 13:48 ` Mike Galbraith 2015-04-30 14:07 ` Daniel Phillips 2015-04-30 14:28 ` Howard Chu 2015-04-30 14:28 ` Howard Chu 2015-04-30 15:14 ` Daniel Phillips 2015-04-30 16:00 ` Howard Chu 2015-04-30 18:22 ` Christian Stroetmann 2015-05-11 22:12 ` Pavel Machek 2015-05-11 23:17 ` Theodore Ts'o 2015-05-12 2:34 ` Daniel Phillips 2015-05-12 5:38 ` Dave Chinner 2015-05-12 6:18 ` Daniel Phillips 2015-05-12 6:18 ` Daniel Phillips 2015-05-12 18:39 ` David Lang 2015-05-12 20:54 ` Daniel Phillips 2015-05-12 21:30 ` David Lang 2015-05-12 22:27 ` Daniel Phillips 2015-05-12 22:35 ` David Lang 2015-05-12 23:55 ` Theodore Ts'o 2015-05-13 1:26 ` Daniel Phillips 2015-05-13 19:09 ` Martin Steigerwald 2015-05-13 19:37 ` Daniel Phillips 2015-05-13 20:02 ` Jeremy Allison 2015-05-13 20:02 ` Jeremy Allison 2015-05-13 20:24 ` Daniel Phillips 2015-05-13 20:25 ` Martin Steigerwald 2015-05-13 20:38 ` Daniel Phillips 2015-05-13 21:10 ` Martin Steigerwald 2015-05-13 0:31 ` Daniel Phillips 2015-05-12 21:30 ` Christian Stroetmann 2015-05-13 7:20 ` Pavel Machek 2015-05-13 13:47 ` Elifarley Callado Coelho Cruz 2015-05-12 9:03 ` Pavel Machek 2015-05-12 9:03 ` Pavel Machek 2015-05-12 11:22 ` Daniel Phillips 2015-05-12 13:26 ` Howard Chu 2015-05-11 23:53 ` Daniel Phillips 2015-05-11 23:53 ` Daniel Phillips 2015-05-12 0:12 ` David Lang 2015-05-12 4:36 ` Daniel Phillips 2015-05-12 17:30 ` Christian Stroetmann 2015-05-13 7:25 ` Pavel Machek 2015-05-13 11:31 ` Daniel Phillips 2015-05-13 12:41 ` Daniel Phillips 2015-05-13 13:08 ` Mike Galbraith 2015-05-13 13:15 ` Daniel Phillips 2015-04-30 14:33 ` Mike Galbraith 2015-04-30 15:24 ` Daniel Phillips 2015-04-30 15:24 ` Daniel Phillips 2015-04-29 20:40 ` Tux3 Report: How fast can we fsync? Daniel Phillips 2015-04-29 20:40 ` Daniel Phillips 2015-04-29 22:06 ` OGAWA Hirofumi 2015-04-29 22:06 ` OGAWA Hirofumi 2015-04-30 3:57 ` Mike Galbraith 2015-04-30 3:50 ` Mike Galbraith 2015-04-30 10:59 ` Daniel Phillips 2015-04-30 1:46 ` Dave Chinner 2015-04-30 10:28 ` Daniel Phillips 2015-04-30 10:28 ` Daniel Phillips [not found] ` <55420EAC.5040900@suse.com> 2015-04-30 11:36 ` Daniel Phillips 2015-04-30 13:19 ` Filipe David Manana 2015-04-30 13:25 ` Daniel Phillips 2015-05-01 15:38 ` Dave Chinner 2015-05-01 23:20 ` Daniel Phillips 2015-05-02 1:07 ` David Lang 2015-05-02 10:26 ` Daniel Phillips 2015-05-02 16:00 ` Christian Stroetmann 2015-05-02 16:30 ` Richard Weinberger 2015-05-02 17:00 ` Christian Stroetmann 2015-05-12 17:41 ` Daniel Phillips 2015-05-12 17:46 ` Tux3 Report: How fast can we fail? Daniel Phillips 2015-05-13 22:07 ` Daniel Phillips 2015-05-26 10:03 ` Pavel Machek 2015-05-26 10:03 ` Pavel Machek 2015-05-27 6:41 ` Mosis Tembo 2015-05-27 18:28 ` Daniel Phillips 2015-05-27 18:28 ` Daniel Phillips 2015-05-27 21:39 ` Pavel Machek 2015-05-27 22:46 ` Daniel Phillips 2015-05-28 12:55 ` Austin S Hemmelgarn 2015-05-27 7:37 ` Mosis Tembo 2015-05-27 14:04 ` Austin S Hemmelgarn 2015-05-27 15:21 ` Mosis Tembo 2015-05-27 15:37 ` Austin S Hemmelgarn 2015-05-14 7:37 ` [WIP] tux3: Optimized fsync Daniel Phillips 2015-05-14 8:26 ` [FYI] tux3: Core changes Daniel Phillips 2015-05-14 12:59 ` Rik van Riel 2015-05-15 0:06 ` Daniel Phillips 2015-05-15 0:06 ` Daniel Phillips 2015-05-15 3:06 ` Rik van Riel 2015-05-15 8:09 ` Mel Gorman 2015-05-15 9:54 ` Daniel Phillips 2015-05-15 9:54 ` Daniel Phillips 2015-05-15 11:00 ` Mel Gorman 2015-05-16 22:38 ` David Lang 2015-05-18 12:57 ` Mel Gorman 2015-05-18 12:57 ` Mel Gorman 2015-05-15 9:38 ` Daniel Phillips 2015-05-15 9:38 ` Daniel Phillips 2015-05-27 7:41 ` Pavel Machek 2015-05-27 18:09 ` Daniel Phillips 2015-05-27 18:09 ` Daniel Phillips 2015-05-27 21:37 ` Pavel Machek 2015-05-27 22:33 ` Daniel Phillips 2015-05-15 8:05 ` Mel Gorman 2015-05-17 13:26 ` Boaz Harrosh 2015-05-18 2:20 ` Rik van Riel 2015-05-18 7:58 ` Boaz Harrosh 2015-05-19 4:46 ` Daniel Phillips 2015-05-21 19:43 ` [WIP][PATCH] tux3: preliminatry nospace handling Daniel Phillips 2015-05-19 14:00 ` [FYI] tux3: Core changes Jan Kara 2015-05-19 19:18 ` Daniel Phillips 2015-05-19 20:33 ` David Lang 2015-05-19 20:33 ` David Lang 2015-05-20 14:44 ` Jan Kara 2015-05-20 16:22 ` Daniel Phillips 2015-05-20 18:01 ` David Lang 2015-05-20 18:01 ` David Lang 2015-05-20 19:53 ` Rik van Riel 2015-05-20 19:53 ` Rik van Riel 2015-05-20 22:51 ` Daniel Phillips 2015-05-20 22:51 ` Daniel Phillips 2015-05-21 3:24 ` Daniel Phillips 2015-05-21 3:51 ` David Lang 2015-05-21 19:53 ` Daniel Phillips 2015-05-21 19:53 ` Daniel Phillips 2015-05-26 4:25 ` Rik van Riel 2015-05-26 4:25 ` Rik van Riel 2015-05-26 4:30 ` Daniel Phillips 2015-05-26 4:30 ` Daniel Phillips 2015-05-26 6:04 ` David Lang 2015-05-26 6:04 ` David Lang 2015-05-26 6:11 ` Daniel Phillips 2015-05-26 6:13 ` David Lang 2015-05-26 6:13 ` David Lang 2015-05-26 8:09 ` Daniel Phillips 2015-05-26 8:09 ` Daniel Phillips 2015-05-26 10:13 ` Pavel Machek 2015-05-26 10:13 ` Pavel Machek 2015-05-26 7:09 ` Jan Kara 2015-05-26 8:08 ` Daniel Phillips 2015-05-26 8:08 ` Daniel Phillips 2015-05-26 9:00 ` Jan Kara 2015-05-26 9:00 ` Jan Kara 2015-05-26 20:22 ` Daniel Phillips 2015-05-26 21:36 ` Rik van Riel 2015-05-26 21:49 ` Daniel Phillips [this message] 2015-05-26 21:49 ` Daniel Phillips 2015-05-27 8:41 ` Jan Kara 2015-06-21 15:36 ` OGAWA Hirofumi 2015-06-21 15:36 ` OGAWA Hirofumi 2015-06-23 16:12 ` Jan Kara 2015-07-05 12:54 ` OGAWA Hirofumi 2015-07-05 12:54 ` OGAWA Hirofumi 2015-07-09 16:05 ` Jan Kara 2015-07-09 16:05 ` Jan Kara 2015-07-31 4:44 ` OGAWA Hirofumi 2015-07-31 15:37 ` Raymond Jennings 2015-07-31 17:27 ` Daniel Phillips 2015-07-31 17:27 ` Daniel Phillips 2015-07-31 18:29 ` David Lang 2015-07-31 18:29 ` David Lang 2015-07-31 18:43 ` Daniel Phillips 2015-07-31 18:43 ` Daniel Phillips 2015-07-31 22:12 ` Daniel Phillips 2015-07-31 22:12 ` Daniel Phillips 2015-07-31 22:27 ` David Lang 2015-08-01 0:00 ` Daniel Phillips 2015-08-01 0:00 ` Daniel Phillips 2015-08-01 0:16 ` Daniel Phillips 2015-08-01 0:16 ` Daniel Phillips 2015-08-03 13:07 ` Jan Kara 2015-08-01 10:55 ` Elifarley Callado Coelho Cruz 2015-08-18 16:39 ` Rik van Riel 2015-08-03 13:42 ` Jan Kara 2015-08-03 13:42 ` Jan Kara 2015-08-09 13:42 ` OGAWA Hirofumi 2015-08-10 12:45 ` Jan Kara 2015-08-10 12:45 ` Jan Kara 2015-08-16 19:42 ` OGAWA Hirofumi 2015-05-26 10:22 ` Sergey Senozhatsky 2015-05-26 12:33 ` Jan Kara 2015-05-26 12:33 ` Jan Kara 2015-05-26 19:18 ` Daniel Phillips
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