From: Andreas Philipp <philipp.andreas@gmail.com>
To: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
Cc: btrfs <linux-btrfs@vger.kernel.org>,
Andreas Philipp <philipp.andreas@gmail.com>
Subject: Re: No SysRq remount because sb->s_bdev is NULL
Date: Sat, 28 Jul 2012 18:30:36 +0200 [thread overview]
Message-ID: <501413AC.1070900@gmail.com> (raw)
In-Reply-To: <2108513.KBpvBiH5fV@nezir>
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On 28.07.2012 16:50, Florian Albrechtskirchinger wrote:
> On Saturday, July 28, 2012 15:46:50 Andreas Philipp wrote:
>> On 28.07.2012 15:41, Florian Albrechtskirchinger wrote:
>>> During a SysRq emergency remount Btrfs mounts are not remounted. I
tracked
>>> the issue down to this line in do_emergency_remount() in fs/super.c:
>>> if (sb->s_root && sb->s_bdev && (sb->s_flags & MS_BORN) &&
>>> !(sb->s_flags & MS_RDONLY))
>>> s_bdev is NULL for Btrfs super blocks and subsequently
do_remount_sb() is
>>> never called. I couldn't think of a solution, besides resorting to
an ugly
>>> strcmp(sb->s_type->name, "btrfs"), without adding a field to struct
>>> super_block or similar changes.
>>> Thoughts?
>>
>> Just a first thought. Is there a possibility to write a dummy value into
>> sb->s_bdev for btrfs super blocks. Thus it will not be NULL and
>> everything in do_emergency_remount() in fs/super.c will work as wanted.
>
> Then other code paths testing sb->s_bdev for NULL and assuming a
non-NULL sb-
>> s_bdev is a valid block device would fail.
Sorry, I thought that there are separate checks whether the value of
sb->s_bdev is a valid block device.
Thanks,
Andreas
>>
>
> Flo
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prev parent reply other threads:[~2012-07-28 16:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-28 13:41 No SysRq remount because sb->s_bdev is NULL Florian Albrechtskirchinger
2012-07-28 13:46 ` Andreas Philipp
2012-07-28 14:50 ` Florian Albrechtskirchinger
2012-07-28 16:30 ` Andreas Philipp [this message]
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