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From: Pavel Machek <pavel@suse.cz>
To: jim owens <jowens@hp.com>
Cc: linux-fsdevel@vger.kernel.org, Dave Chinner <david@fromorbit.com>,
	Theodore Tso <tytso@mit.edu>,
	Arjan van de Ven <arjan@infradead.org>,
	Miklos Szeredi <miklos@szeredi.hu>,
	hch@infradead.org, t-sato@yk.jp.nec.com,
	akpm@linux-foundation.org, viro@ZenIV.linux.org.uk,
	linux-ext4@vger.kernel.org, xfs@oss.sgi.com, dm-devel@redhat.com,
	linux-kernel@vger.kernel.org, axboe@kernel.dk,
	mtk.manpages@googlemail.com
Subject: Re: [PATCH 3/3] Add timeout feature
Date: Sun, 13 Jul 2008 14:06:02 +0200	[thread overview]
Message-ID: <20080713120602.GC7517@elf.ucw.cz> (raw)
In-Reply-To: <4874C3E8.20804@hp.com>

Hi!

> NEED - provide way for SAN and hardware raid storage to do
> its snapshot/copy function while the system was in-use and
> get an image that could mount cleanly.  Without freeze, at
> a minimum we usually needed filesystem metadata recovery
> to run, worst case is completely unusable snapshits :)
>
> freezefs() is single-level:
>
>    ENOTSUPPOTED - by any other fs
>    EOK - done
>    EINPROGRESS
>    EALREADY
>
> As implemented, freezefs only ensures the metadata is
> consistent so the filesystem copy can mount anywhere.
>
> This means ONLY SOME metadata (or no metadata) is flushed and
> then all metadata updates are stopped.  User/kernel writes
> to already allocated file pages WILL go to a frozen disk.

That's the difference here. They do write file data, and thus avoid
mmap()-writes problem.

...and they _still_ provide auto-thaw.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

  parent reply	other threads:[~2008-07-13 12:05 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-30 12:24 [PATCH 3/3] Add timeout feature Takashi Sato
2008-07-01  8:10 ` Christoph Hellwig
2008-07-01 10:52   ` Alasdair G Kergon
2008-07-03 12:11     ` Takashi Sato
2008-07-03 12:47       ` Alasdair G Kergon
2008-07-03 22:11         ` [dm-devel] " Dave Chinner
2008-07-04 12:08           ` Takashi Sato
2008-07-03 14:45       ` Eric Sandeen
2008-07-07 11:07   ` Pavel Machek
2008-07-08 23:10     ` Dave Chinner
2008-07-08 23:20       ` Pavel Machek
     [not found]       ` <20080708232031.GE18195@elf.ucw.cz>
2008-07-09  0:52         ` Dave Chinner
2008-07-09  1:09           ` Theodore Tso
     [not found]           ` <20080709010922.GE9957@mit.edu>
2008-07-09  4:21             ` Brad Boyer
2008-07-09  6:13             ` Miklos Szeredi
2008-07-09  6:16               ` Christoph Hellwig
2008-07-09  6:22                 ` Miklos Szeredi
2008-07-09  6:41                   ` Arjan van de Ven
2008-07-09  6:48                     ` Miklos Szeredi
2008-07-09  6:55                       ` Arjan van de Ven
2008-07-09  7:08                         ` Miklos Szeredi
2008-07-09 20:48                           ` Pavel Machek
2008-07-09  7:13                         ` Dave Chinner
2008-07-09 11:09                           ` Theodore Tso
2008-07-09 11:49                             ` Dave Chinner
     [not found]                             ` <20080709114958.GV11558@disturbed>
2008-07-09 12:24                               ` Theodore Tso
     [not found]                               ` <20080709122401.GK9957@mit.edu>
2008-07-09 12:59                                 ` Olaf Frączyk
2008-07-09 13:57                                   ` Arjan van de Ven
2008-07-09 13:55                               ` Arjan van de Ven
2008-07-09 13:58                               ` jim owens
2008-07-09 14:13                                 ` jim owens
2008-07-13 12:06                                 ` Pavel Machek [this message]
2008-07-13 17:15                                   ` jim owens
2008-07-14  6:36                                     ` Pavel Machek
2008-07-14 13:17                                       ` jim owens
2008-07-14 13:12                                 ` Takashi Sato
2008-07-14 14:04                                   ` jim owens
2008-07-09 13:53                           ` Arjan van de Ven
2008-07-09  6:59                     ` Dave Chinner
2008-07-09  7:13                       ` Miklos Szeredi
2008-07-09  7:33                         ` Dave Chinner
2008-07-09  8:11                           ` Miklos Szeredi
2008-07-09 11:15                             ` Dave Chinner
2008-07-09 20:44           ` Pavel Machek
  -- strict thread matches above, loose matches on Subject: below --
2008-09-08 11:53 Takashi Sato
2008-09-08 17:11 ` Christoph Hellwig
2008-09-25 21:06   ` Ric Wheeler
2008-09-26  8:52     ` Takashi Sato
2008-09-26 10:58       ` Ric Wheeler
2008-09-29 11:11         ` Takashi Sato
2008-09-26 12:35       ` Valdis.Kletnieks
2008-09-29 14:13       ` Christoph Hellwig
2008-09-29 14:36         ` Eric Sandeen
2008-09-29 14:37           ` Christoph Hellwig
2008-09-29 14:45             ` Eric Sandeen
2008-09-29 22:08               ` jim owens
2008-10-05 10:00               ` Pavel Machek
2008-10-09 10:12               ` Takashi Sato
2008-10-09 10:18                 ` Christoph Hellwig
2008-08-18 12:28 Takashi Sato
2008-08-21 20:20 ` Andrew Morton
2008-08-22 18:16   ` Christoph Hellwig
2008-08-24 17:03   ` Oleg Nesterov
2008-08-29  9:39   ` Takashi Sato
2008-07-22  9:36 Takashi Sato
2008-06-24  7:00 Takashi Sato
2008-06-24 22:09 ` Andrew Morton
2008-06-27 11:33   ` Takashi Sato
2008-06-27 18:57     ` Andrew Morton
2008-06-29 23:13       ` Takashi Sato
2008-06-30  0:01         ` Andrew Morton

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