From: "Takashi Sato" <t-sato@yk.jp.nec.com>
Subject: Re: [RFC PATCH 1/3] Implement generic freeze feature
Date: Wed, 21 May 2008 10:23:23 +0900
Message-ID: <1AE3C150C90A4C1A8C024C3D6079C948@nsl.ad.nec.co.jp>
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	<20080520035712.GA7252@webber.adilger.int>
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Cc: linux-fsdevel@vger.kernel.org, dm-devel@redhat.com,
	linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, xfs@oss.sgi.com
To: "Andreas Dilger" <adilger@sun.com>
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Hi,

Andreas Dilger wrote:
>> +static int ioctl_freeze(struct file *filp)
>> +{
>> +    struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
>> +
>> +    if (!capable(CAP_SYS_ADMIN))
>> +        return -EPERM;
>> +
>> +    /* If filesystem doesn't support freeze feature, return. */
>> +    if (sb->s_op->write_super_lockfs == NULL)
>> +        return -EINVAL;
> 
> Should this be EINVAL, or EOPNOTSUPP?  Usually EINVAL means there is
> something wrong with the passed ioctl parameters (e.g. bad value),
> while EOPNOTSUPP is "operation not supported" and makes more sense.

Sounds good.
I will send new patch-set which is rebased to 2.6.26-rc3 and includes
this fix, in this weekend.

Cheers, Takashi