public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Andi Kleen <andi@firstfloor.org>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	linux-kernel@vger.kernel.org, xfs@oss.sgi.com,
	Alasdair G Kergon <agk@redhat.com>,
	Andi Kleen <andi-suse@firstfloor.org>,
	Milan Broz <mbroz@redhat.com>
Subject: Re: Device loses barrier support (was: Fixed patch for simple barriers.)
Date: Thu, 4 Dec 2008 23:15:51 +0100	[thread overview]
Message-ID: <20081204221551.GV6703@one.firstfloor.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0812041401210.23079@hs20-bc2-1.build.redhat.com>

> If you are pushing what you are pushing --- barriers allowing to return 
> EOPNOTSUPP anytime --- then asynchronous barrier submits can no longer be 
> used, because by the time EOPNOTSUPP is detected, the filesystem is 
> already corrupted.

Chris Mason pointed out that this can actually already happen. From
a quick review this can happen in MD raid1 at least (their barriers_work
flag is pretty similar to the DM implementation I did).  So everyone
has to handle this already anyways.

> I'm wondering, where in fsync() does Linux wait for hardware disk cache to 
> be flushed? Isn't there a bug that fsync() will return before the cache is 
> flushed? I couldn't really find it. The last thing do_fsync calls is 
> filemap_fdatawait and it doesn't do cache flush (blkdev_issue_flush).

At least in fsync() on journaling fs the metadata update should push it.

-Andi

-- 
ak@linux.intel.com

  reply	other threads:[~2008-12-04 22:04 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.64.0812040009340.15169@hs20-bc2-1.build.redhat.com>
     [not found] ` <20081204100050.GN6703@one.firstfloor.org>
2008-12-04 14:00   ` Device loses barrier support (was: Fixed patch for simple barriers.) Mikulas Patocka
2008-12-04 14:20     ` Andi Kleen
2008-12-04 14:17       ` Mikulas Patocka
2008-12-04 14:58         ` Andi Kleen
2008-12-04 16:45           ` Mikulas Patocka
2008-12-04 17:48             ` Andi Kleen
2008-12-04 17:53               ` Christoph Hellwig
2008-12-04 19:37               ` Mikulas Patocka
2008-12-04 22:15                 ` Andi Kleen [this message]
2008-12-04 23:08                   ` Mikulas Patocka
2008-12-05  0:48                     ` Andi Kleen
2008-12-05  1:16                       ` Mikulas Patocka
2008-12-05  1:37                         ` Andi Kleen
2008-12-05  2:21                           ` Mikulas Patocka
2008-12-05  3:09                             ` Andi Kleen
2008-12-05 11:52                           ` Alan Cox
2008-12-05 12:29                             ` Andi Kleen
2008-12-05  3:26                 ` Device loses barrier support Eric Sandeen
2008-12-07  4:17             ` Device loses barrier support (was: Fixed patch for simple barriers.) Dave Chinner
2008-12-05  5:44           ` Device loses barrier support Timothy Shimmin
     [not found] <bFnGM-7mA-5@gated-at.bofh.it>
     [not found] ` <bFpyX-1jh-15@gated-at.bofh.it>
     [not found]   ` <bFquY-2x2-5@gated-at.bofh.it>
     [not found]     ` <bFsnc-51o-37@gated-at.bofh.it>
     [not found]       ` <bFuyC-7Zt-11@gated-at.bofh.it>
     [not found]         ` <bFvuI-L8-29@gated-at.bofh.it>
     [not found]           ` <bFwTJ-2oc-13@gated-at.bofh.it>
     [not found]             ` <bFxwq-3g7-1@gated-at.bofh.it>
     [not found]               ` <bFxGa-3pz-1@gated-at.bofh.it>
     [not found]                 ` <bFHvW-7up-5@gated-at.bofh.it>
     [not found]                   ` <bFHPd-84I-13@gated-at.bofh.it>
2008-12-05 18:21                     ` Device loses barrier support (was: Fixed patch for simple barriers.) Bodo Eggert
2008-12-05 18:41                       ` Andi Kleen

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=20081204221551.GV6703@one.firstfloor.org \
    --to=andi@firstfloor.org \
    --cc=agk@redhat.com \
    --cc=andi-suse@firstfloor.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mbroz@redhat.com \
    --cc=mpatocka@redhat.com \
    --cc=xfs@oss.sgi.com \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox