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Some problems

DISCUSSION Dipl.-Ing. Michael Niederle 2 participants 3 messages May 23, 2009 – May 25, 2009 3 messages not in the archive NILFS2 filesystem

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#2 lore raw

Hi!

I continue testing nilfs as a root file system. Until now I have no script to cleanly unmount the root file system. (In the layered approach (aufs) I used before this was not necessary.) So I just called sync and then shut down the system.

The next boot took some time, because the superblock was "broken". Here an extract from the kernel log:

[    1.407323] NILFS warning: broken superblock. using spare superblock.
[    1.408569] NILFS warning: broken superblock. using spare superblock.
[  461.587031] segctord starting. Construction interval = 5 seconds, CP
frequency < 30 seconds [  461.591873] NILFS warning: mounting unchecked fs
[  461.629865] NILFS: recovery complete.

Is nilfs doing a sequential scan over the whole partition to find its spare superblock?

Then I wanted to remove some snapshots:

Quoted 1 line

lscp -s

                 CNO        DATE     TIME  MODE  FLG   NBLKINC       ICNT
                 685  2009-05-13 09:38:20   ss    -         35     568722
                1330  2009-05-13 10:59:41   ss    i       7629     579584
                4466  2009-05-14 19:15:28   ss    -         23     589270
                8250  2009-05-16 03:40:42   ss    i       6202     597141
                9910  2009-05-17 19:14:54   ss    -         49     626715
               10380  2009-05-17 20:21:53   ss    -         18     647228
               10620  2009-05-23 21:45:41   ss    i       6054     646978
Quoted 1 line

rmcp 685

rmcp: 685: operation not permitted

What's the cause of this message? (rmcp also failed for all other snapshots; the failed rmcp did not produce any kernel message)

Greetings, Michael

#3 lore raw

Hi!,

Quoted 6 lines · Dipl.-Ing. Michael Niederle

Hi!

I continue testing nilfs as a root file system. Until now I have no script to cleanly unmount the root file system. (In the layered approach (aufs) I used before this was not necessary.) So I just called sync and then shut down the system.

I made a Debian lenny on my pendrive. It looks remount my root nilfs partition readonly on shutdown, and no trouble so far.

Quoted 11 lines

The next boot took some time, because the superblock was "broken". Here an extract from the kernel log:

[    1.407323] NILFS warning: broken superblock. using spare superblock.
[    1.408569] NILFS warning: broken superblock. using spare superblock.
[  461.587031] segctord starting. Construction interval = 5 seconds, CP
frequency < 30 seconds [  461.591873] NILFS warning: mounting unchecked fs
[  461.629865] NILFS: recovery complete.

Is nilfs doing a sequential scan over the whole partition to find its spare superblock?

No, the location of spare superblock is determined by size of the divice. It's in tail of the partition.

I think the spare superblock pointed to a certain old segment and it took some time to scan forward from the old segment to the latest segment.

It may take about a minute, but something is wrong if it took several minutes.

Quoted 12 lines

Then I wanted to remove some snapshots:

Quoted 1 line

lscp -s

                 CNO        DATE     TIME  MODE  FLG   NBLKINC       ICNT
                 685  2009-05-13 09:38:20   ss    -         35     568722
                1330  2009-05-13 10:59:41   ss    i       7629     579584
                4466  2009-05-14 19:15:28   ss    -         23     589270
                8250  2009-05-16 03:40:42   ss    i       6202     597141
                9910  2009-05-17 19:14:54   ss    -         49     626715
               10380  2009-05-17 20:21:53   ss    -         18     647228
               10620  2009-05-23 21:45:41   ss    i       6054     646978
Quoted 5 lines
Quoted 1 line

rmcp 685

rmcp: 685: operation not permitted

What's the cause of this message? (rmcp also failed for all other snapshots; the failed rmcp did not produce any kernel message)

rmcp is allowed only for plain checkpoints. So, you have to change it to the plain checkpoint like

 # chcp cp 685 1330 ...
 # rmcp 685 ...

Actually, you don't have to do the rmcp because the garbage collection will delete plain checkpoints.

I remember someone asked a simliar question before.

I think we should make the error message more user-friendly. And we should allow force option of rmcp to remove snapshots; the current force option does not have this meaning.

Cheers,
Ryusuke Konishi

A message that is not in the archive (sent off-list or not yet received): [email protected]

#5 lore raw
Quoted 12 lines · Ryusuke Konishi
Quoted 5 lines
Quoted 1 line

rmcp 685

rmcp: 685: operation not permitted

What's the cause of this message? (rmcp also failed for all other snapshots; the failed rmcp did not produce any kernel message)

rmcp is allowed only for plain checkpoints. So, you have to change it to the plain checkpoint like

 # chcp cp 685 1330 ...
 # rmcp 685 ...
Quoted 8 lines

Actually, you don't have to do the rmcp because the garbage collection will delete plain checkpoints.

I remember someone asked a simliar question before.

I think we should make the error message more user-friendly. And we should allow force option of rmcp to remove snapshots; the current force option does not have this meaning.

I found the current error code against the removal for snapshots is badly assigned, and rmcp cannot distinguish it from real permission errors.

So, first I'm thinking to change the error code to EBUSY or something.

Regards,
Ryusuke Konishi