From: Goffredo Baroncelli <kreijack@gmail.com>
To: Hugo Mills <hugo@carfax.org.uk>
Cc: Chris Murphy <lists@colorremedies.com>,
"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: device delete, error removing device
Date: Mon, 22 Oct 2012 22:35:02 +0200 [thread overview]
Message-ID: <5085ADF6.6050603@gmail.com> (raw)
In-Reply-To: <20121022195002.GB25498@carfax.org.uk>
On 2012-10-22 21:50, Hugo Mills wrote:
>>>>> It's more like a balance which moves everything that has
>>>>> some (part of its) existence on a device. So when you have
>>>>> RAID-0 or RAID-1 data, all of the related chunks on other
>>>>> disks get moved too (so in RAID-1, it's the mirror chunk as
>>>>> well as the chunk on the removed disk that gets
>>>>> rewritten).
>>>
>>> Does this mean "device delete" depends on an ability to make
>>> writes to the device being removed? I immediately think of SSD
>>> failures, which seem to fail writing, while still being able to
>>> reliably read. Would that behavior inhibit the ability to
>>> remove the device from the volume?
> No, the device being removed isn't modified at all. (Which causes
> its own set of weird problemettes, but I think most of those have
> gone away).
IIRC, when a device is deleted, the 1st superblock is zeroed.
Moreover btrfs needs to be able to read the device in order to delete
it. Of course these rules aren't applied when a device is classified
as "missing".
See the function btrfs_rm_device() in fs/btrfs/volumes.c for the details.
>
--
gpg @keyserver.linux.it: Goffredo Baroncelli (kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
next prev parent reply other threads:[~2012-10-22 20:34 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 4:32 device delete, error removing device Chris Murphy
2012-10-22 5:04 ` dima
2012-10-22 5:30 ` Chris Murphy
2012-10-22 6:02 ` Chris Murphy
2012-10-22 9:19 ` Hugo Mills
2012-10-22 16:42 ` Chris Murphy
2012-10-22 17:04 ` Goffredo Baroncelli
2012-10-22 19:36 ` Chris Murphy
2012-10-22 19:50 ` Hugo Mills
2012-10-22 20:35 ` Goffredo Baroncelli [this message]
2012-10-22 20:46 ` Chris Murphy
2012-10-22 17:18 ` Hugo Mills
2012-10-23 7:57 ` Michael Kjörling
2012-10-23 18:10 ` Goffredo Baroncelli
2012-10-23 18:17 ` Chris Murphy
2012-10-23 19:02 ` Goffredo Baroncelli
2012-10-23 20:28 ` Chris Murphy
2012-10-23 22:16 ` Goffredo Baroncelli
2012-10-23 22:29 ` Chris Murphy
2012-10-24 18:06 ` device delete, error removing device [SOLVED] Goffredo Baroncelli
2012-10-24 19:13 ` Chris Murphy
2012-10-24 21:30 ` Goffredo Baroncelli
2012-10-24 21:43 ` Chris Murphy
2012-10-25 19:26 ` Goffredo Baroncelli
2012-10-27 18:25 ` device delete, error removing device Chris Murphy
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