All of lore.kernel.org
 help / color / mirror / Atom feed
From: Chris Vest <chris.vest@neotechnology.com>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Kevin Wolf <kwolf@redhat.com>,
	lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, Christoph Hellwig <hch@infradead.org>,
	Ric Wheeler <rwheeler@redhat.com>, Rik van Riel <riel@redhat.com>
Subject: Re: [LSF/MM TOPIC] I/O error handling and fsync()
Date: Wed, 11 Jan 2017 13:14:13 +0100	[thread overview]
Message-ID: <A8FCA794-E868-4659-9EEA-D6A5B4AEF2AA@neotechnology.com> (raw)
In-Reply-To: <20170111050356.ldlx73n66zjdkh6i@thunk.org>


> On 11 Jan 2017, at 06.03, Theodore Ts'o <tytso@mit.edu> wrote:
> 
> So an approach that might work is fsync() will keep the pages dirty
> --- but only while the file descriptor is open.  This could either be
> the default behavior, or something that has to be specifically
> requested via fcntl(2).  That way, as soon as the process exits (at
> which point it will be too late for it do anything to save the
> contents of the file) we also release the memory.  And if the process
> gets OOM killed, again, the right thing happens.  But if the process
> wants to take emergency measures to write the file somewhere else, it
> knows that the pages won't get lost until the file gets closed.

I think this sounds like a very reasonable default. Before reading this thread, it would have been my first guess as to how this worked. It gives the program the opportunity to retry the fsyncs, before aborting. It will also allow a database, for instance, to keep servicing reads until the issue resolves itself, or an administrator intervenes. A program cannot allow reads from the file if pages that has been written to can be evicted, and their changes lost, and then brought back with old data.

--
Chris Vest
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

      parent reply	other threads:[~2017-01-11 12:14 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-10 16:02 [LSF/MM TOPIC] I/O error handling and fsync() Kevin Wolf
2017-01-11  0:41 ` NeilBrown
2017-01-13 11:09   ` Kevin Wolf
2017-01-13 14:21     ` Theodore Ts'o
2017-01-13 16:00       ` Kevin Wolf
2017-01-13 22:28         ` NeilBrown
2017-01-14  6:18           ` Darrick J. Wong
2017-01-16 12:14           ` [Lsf-pc] " Jeff Layton
2017-01-22 22:44             ` NeilBrown
2017-01-22 23:31               ` Jeff Layton
2017-01-23  0:21                 ` Theodore Ts'o
2017-01-23 10:09                   ` Kevin Wolf
2017-01-23 12:10                     ` Jeff Layton
2017-01-23 12:10                       ` Jeff Layton
2017-01-23 17:25                       ` Theodore Ts'o
2017-01-23 17:53                         ` Chuck Lever
2017-01-23 22:40                         ` Jeff Layton
2017-01-23 22:40                           ` Jeff Layton
2017-01-23 22:35                     ` Jeff Layton
2017-01-23 22:35                       ` Jeff Layton
2017-01-23 23:09                       ` Trond Myklebust
2017-01-24  0:16                         ` NeilBrown
2017-01-24  0:16                           ` NeilBrown
2017-01-24  0:46                           ` Jeff Layton
2017-01-24  0:46                             ` Jeff Layton
2017-01-24 21:58                             ` NeilBrown
2017-01-24 21:58                               ` NeilBrown
2017-01-25 13:00                               ` Jeff Layton
2017-01-25 13:00                                 ` Jeff Layton
2017-01-30  5:30                                 ` NeilBrown
2017-01-30  5:30                                   ` NeilBrown
2017-01-24  3:34                           ` Trond Myklebust
2017-01-25 18:35                             ` Theodore Ts'o
2017-01-26  0:36                               ` NeilBrown
2017-01-26  0:36                                 ` NeilBrown
2017-01-26  9:25                                 ` Jan Kara
2017-01-26 22:19                                   ` NeilBrown
2017-01-26 22:19                                     ` NeilBrown
2017-01-27  3:23                                     ` Theodore Ts'o
2017-01-27  6:03                                       ` NeilBrown
2017-01-27  6:03                                         ` NeilBrown
2017-01-30 16:04                                       ` Jan Kara
2017-01-13 18:40     ` Al Viro
2017-01-13 19:06       ` Kevin Wolf
2017-01-11  5:03 ` Theodore Ts'o
2017-01-11  9:47   ` [Lsf-pc] " Jan Kara
2017-01-11 15:45     ` Theodore Ts'o
2017-01-11 10:55   ` Chris Vest
2017-01-11 11:40   ` Kevin Wolf
2017-01-13  4:51     ` NeilBrown
2017-01-13 11:51       ` Kevin Wolf
2017-01-13 21:55         ` NeilBrown
2017-01-11 12:14   ` Chris Vest [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=A8FCA794-E868-4659-9EEA-D6A5B4AEF2AA@neotechnology.com \
    --to=chris.vest@neotechnology.com \
    --cc=hch@infradead.org \
    --cc=kwolf@redhat.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=lsf-pc@lists.linux-foundation.org \
    --cc=riel@redhat.com \
    --cc=rwheeler@redhat.com \
    --cc=tytso@mit.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.