From: Dan Williams <dan.j.williams@intel.com>
To: "Hawrylewicz Czarnowski,
Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Cc: Neil Brown <neilb@suse.de>,
"linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>,
"Ciechanowski, Ed" <ed.ciechanowski@intel.com>,
"Labun, Marcin" <Marcin.Labun@intel.com>,
"Czarnowska, Anna" <anna.czarnowska@intel.com>
Subject: Re: [PATCH] fix: mdadm -Ss for external metadata don't stop container
Date: Tue, 07 Dec 2010 08:09:07 -0800 [thread overview]
Message-ID: <4CFE5C23.4070603@intel.com> (raw)
In-Reply-To: <66C59AD0932712458090B447266D638C010BD52E6C@irsmsx504.ger.corp.intel.com>
On 12/7/2010 3:07 AM, Hawrylewicz Czarnowski, Przemyslaw wrote:
>> I've applied this, but I'm not 100% sure it is completely safe.
>> mdmon holds the O_EXCL open to be sure that mdadm isn't creating or
>> assembling another array in the container.
>> mdadm will get an O_EXCL and then try sending a signal to mdmon. If it
>> succeeds, it knows mdmon is still running. But this patch might open a
>> window where mdadm can get O_EXCL, and a signal still works.
> On the manual pages, behavior of O_EXCL is only defined in connection with O_CREAT flag, which is not present in open_dev_excl (of course:). I have just make test for open(name, O_RDWR | O_EXCL) few times on the same file and it does not block other processes...
Try the same test on a device special file.
--
Dan
next prev parent reply other threads:[~2010-12-07 16:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-07 6:44 [PATCH] fix: mdadm -Ss for external metadata don't stop container Hawrylewicz Czarnowski, Przemyslaw
2010-12-07 10:16 ` Neil Brown
2010-12-07 11:07 ` Hawrylewicz Czarnowski, Przemyslaw
2010-12-07 16:09 ` Dan Williams [this message]
2011-03-16 22:24 ` Hawrylewicz Czarnowski, Przemyslaw
2011-03-17 2:38 ` NeilBrown
2011-03-17 16:51 ` Wojcik, Krzysztof
2011-03-17 21:08 ` Hawrylewicz Czarnowski, Przemyslaw
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