Re: [PATCH 6/8] fsfreeze: add vfs ioctl to check freeze state

[Fernando Luis Vazquez Cao <fernando_b1@lab.ntt.co.jp>]

On 2012/07/13 22:54, Jan Kara wrote:
> On Thu 12-07-12 18:10:14, Fernando Luis Vázquez Cao wrote:
>> The FIISFROZEN ioctl can be use by HA and monitoring software to check
>> the freeze state of a mounted filesystem.
>>
>> Cc: Christoph Hellwig <hch@infradead.org>
>> Cc: Jan Kara <jack@suse.cz>
>> Cc: Dave Chinner <dchinner@redhat.com>
>> Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
>> ---
>>
>> diff -urNp vfs-orig/fs/compat_ioctl.c vfs/fs/compat_ioctl.c
>> --- vfs-orig/fs/compat_ioctl.c	2012-07-04 18:57:54.000000000 +0900
>> +++ vfs/fs/compat_ioctl.c	2012-07-12 17:25:37.592626439 +0900
>> @@ -885,6 +885,7 @@ COMPATIBLE_IOCTL(FIGETBSZ)
>>   /* 'X' - originally XFS but some now in the VFS */
>>   COMPATIBLE_IOCTL(FIFREEZE)
>>   COMPATIBLE_IOCTL(FITHAW)
>> +COMPATIBLE_IOCTL(FIISFROZEN)
>>   COMPATIBLE_IOCTL(KDGETKEYCODE)
>>   COMPATIBLE_IOCTL(KDSETKEYCODE)
>>   COMPATIBLE_IOCTL(KDGKBTYPE)
>> diff -urNp vfs-orig/fs/ioctl.c vfs/fs/ioctl.c
>> --- vfs-orig/fs/ioctl.c	2012-07-04 18:57:54.000000000 +0900
>> +++ vfs/fs/ioctl.c	2012-07-12 17:25:37.592626439 +0900
>> @@ -536,6 +536,16 @@ static int ioctl_fsthaw(struct file *fil
>>   	return thaw_super(sb);
>>   }
>>   
>> +static int ioctl_fs_isfrozen(struct file *filp)
>> +{
>> +	struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
>> +
>> +	if (!capable(CAP_SYS_ADMIN))
>> +		return -EPERM;
>> +
>> +	return isfrozen_super(sb);
>> +}
>> +
>    Is there any reason to restrict this to CAP_SYS_ADMIN?

It is just for consistency with what FIFREEZE and FITHAW require
in terms of ACLs. If it is deemed too strict for a check ioctl I can
remove it.

Thanks,
Fernando
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