Re: Error while testing (using loop device)

[Ryusuke Konishi <ryusuke-sG5X7nlA6pw@public.gmane.org>]

Hi,
On Thu, 22 Jul 2010 14:26:38 -0500, Rodrigo_E._De_León_Plicet wrote:
> Hi.
> 
> Ubuntu 10.04
> nilfs-tools 2.0.15
> 
> --------------------------------------------------------------------------------
> 
> rdl@linage:/tmp$ mkdir t
> 
> rdl@linage:/tmp$ mkdir t2
> 
> rdl@linage:/tmp$ chmod 777 t t2
> 
> rdl@linage:/tmp$ dd if=/dev/zero of=test.img bs=1M seek=1000 count=1
> 1+0 records in
> 1+0 records out
> 1048576 bytes (1.0 MB) copied, 0.00422859 s, 248 MB/s
> 
> rdl@linage:/tmp$ mkfs -t nilfs2 test.img
> mkfs.nilfs2 ver 2.0
> Start writing file system initial data to the device
>       Blocksize:4096  Device:test.img  Device Size:1049624576
> File system initialization succeeded !!
> 
> rdl@linage:/tmp$ sudo mount -t nilfs2 -o loop /tmp/test.img /tmp/t
> mount.nilfs2: WARNING! - The NILFS on-disk format may change at any time.
> mount.nilfs2: WARNING! - Do not place critical data on a NILFS filesystem.
> 
> (... time passes ...)
> 
> rdl@linage:/tmp$ lscp
>                 CNO        DATE     TIME  MODE  FLG   NBLKINC       ICNT
>                   1  2010-07-21 15:25:07   cp    -         11          3
>                   2  2010-07-21 15:26:47   cp    -        118          4
>                   3  2010-07-21 15:26:56   cp    -        224          6
>                   4  2010-07-21 15:27:03   cp    -         23         12
>                   5  2010-07-21 15:27:14   cp    -         48         13
> 
> rdl@linage:/tmp$ sudo chcp ss 3
> 
> rdl@linage:/tmp$ lscp
>                 CNO        DATE     TIME  MODE  FLG   NBLKINC       ICNT
>                   1  2010-07-21 15:25:07   cp    -         11          3
>                   2  2010-07-21 15:26:47   cp    -        118          4
>                   3  2010-07-21 15:26:56   ss    -        224          6
>                   4  2010-07-21 15:27:03   cp    -         23         12
>                   5  2010-07-21 15:27:14   cp    -         48         13
>                   6  2010-07-21 15:27:33   cp    -         14         14
> 
> rdl@linage:/tmp$ sudo mount -t nilfs2 -o ro,cp=2,loop /tmp/test.img /tmp/t2
> mount.nilfs2: Error while mounting /dev/loop1 on /tmp/t2: Read-only file system
> 
> rdl@linage:/tmp$ sudo mount -t nilfs2 -r -o cp=2,loop /tmp/test.img /tmp/t2
> mount.nilfs2: Error while mounting /dev/loop1 on /tmp/t2: Read-only file system

How about this?

 $ sudo mount -t nilfs2 -o ro,cp=3,loop=/dev/loop0 /tmp/test.img /tmp/t2

or

 $ sudo mount -t nilfs2 -r -o cp=3,loop=/dev/loop0 /tmp/test.img /tmp/t2
 ...
 $ sudo umount /tmp/t2

Note that you have to manually detach the device like "losetup -d
/dev/loop0" if you once failed to mount it.  This is because the loop
device is handled by the common "mount" program not by "mount.nilfs2".

Regards,
Ryusuke Konishi
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