[PATCH 0/2] nilfs-utils: add skeleton of fsck.nilfs2

[PATCH 0/2] nilfs-utils: add skeleton of fsck.nilfs2

[Vyacheslav Dubeyko]

Hi,

This patch set adds skeleton of fsck.nilfs2 utility into nilfs-utils package. Currently, fsck.nilfs2 only try to check presence of primary and secondary superblocks. It checks magic signature in superblock.

With the best regards,
Vyacheslav Dubeyko.
--
 configure.ac     |    3 ++-
 sbin/Makefile.am |    2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

 sbin/fsck/Makefile.am        |   13 ++
 sbin/fsck/fsck_messages.c    |  254 ++++++++++++++++++++++++
 sbin/fsck/fsck_messages.def  |   62 ++++++
 sbin/fsck/fsck_messages.h    |  110 +++++++++++
 sbin/fsck/fsck_nilfs2.c      |  379 +++++++++++++++++++++++++++++++++++
 sbin/fsck/fsck_nilfs2.h      |   37 ++++
 sbin/fsck/fsck_raw_ops.c     |  413 +++++++++++++++++++++++++++++++++++++++
 sbin/fsck/fsck_raw_ops.h     |   46 +++++
 sbin/fsck/nilfs_superblock.c |  445 ++++++++++++++++++++++++++++++++++++++++++
 sbin/fsck/nilfs_superblock.h |   48 +++++
 10 files changed, 1807 insertions(+), 0 deletions(-)

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Re: [PATCH 0/2] nilfs-utils: add skeleton of fsck.nilfs2

[Ryusuke Konishi]

Hi,
On Sun, 22 Jul 2012 19:13:01 +0400, Vyacheslav Dubeyko wrote:
> Hi,
> 
> This patch set adds skeleton of fsck.nilfs2 utility into nilfs-utils package. Currently, fsck.nilfs2 only try to check presence of primary and secondary superblocks. It checks magic signature in superblock.
> 
> With the best regards,
> Vyacheslav Dubeyko.

I'm planning to look this patchset weekend.

One question is about your plan for proceeding this task.

Implementing fsck looks a tough task since NILFS has history of data
and meta-data as well as the current file system structures, and correcting
filesystem looks to need log write in user-land, which is not yet realized.

So, taking a step-by-step approach seems essential.

In this sense, did you design the skelton, thinking of further steps?
If you have some strategy to accomplish this task, I'd like to hear
that.

My concern for this is avoiding rework of the future.

I'm very thankful for your challenges.

With regards,
Ryusuke Konishi

> --
>  configure.ac     |    3 ++-
>  sbin/Makefile.am |    2 +-
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
>  sbin/fsck/Makefile.am        |   13 ++
>  sbin/fsck/fsck_messages.c    |  254 ++++++++++++++++++++++++
>  sbin/fsck/fsck_messages.def  |   62 ++++++
>  sbin/fsck/fsck_messages.h    |  110 +++++++++++
>  sbin/fsck/fsck_nilfs2.c      |  379 +++++++++++++++++++++++++++++++++++
>  sbin/fsck/fsck_nilfs2.h      |   37 ++++
>  sbin/fsck/fsck_raw_ops.c     |  413 +++++++++++++++++++++++++++++++++++++++
>  sbin/fsck/fsck_raw_ops.h     |   46 +++++
>  sbin/fsck/nilfs_superblock.c |  445 ++++++++++++++++++++++++++++++++++++++++++
>  sbin/fsck/nilfs_superblock.h |   48 +++++
>  10 files changed, 1807 insertions(+), 0 deletions(-)
> 
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Re: [PATCH 0/2] nilfs-utils: add skeleton of fsck.nilfs2

[Vyacheslav Dubeyko]

Hi,

On Wed, 2012-07-25 at 02:36 +0900, Ryusuke Konishi wrote:
> Hi,
> On Sun, 22 Jul 2012 19:13:01 +0400, Vyacheslav Dubeyko wrote:
> > Hi,
> > 
> > This patch set adds skeleton of fsck.nilfs2 utility into nilfs-utils package. Currently, fsck.nilfs2 only try to check presence of primary and secondary superblocks. It checks magic signature in superblock.
> > 
> > With the best regards,
> > Vyacheslav Dubeyko.
> 
> I'm planning to look this patchset weekend.

Ok. I see.

> 
> One question is about your plan for proceeding this task.
> 
> Implementing fsck looks a tough task since NILFS has history of data
> and meta-data as well as the current file system structures, and correcting
> filesystem looks to need log write in user-land, which is not yet realized.
> 

I hope that I clear understand possible long duration and complexity of
this task. Currently, it is not so easy to predict duration of this
task. But, from my point of view, fsck is a key point of NILFS today and
it needs to implement it anyway.

> So, taking a step-by-step approach seems essential.
> 

I agree with you. I am thinking about step-by-step approach also. And
skeleton of fsck is a preparatory step.

> In this sense, did you design the skelton, thinking of further steps?
> If you have some strategy to accomplish this task, I'd like to hear
> that.
> 

Yes, you are right. I have some strategy in my mind.

First of all, I think that implementation can be divided into two big
steps:
1. Implementation fsck's checking functionality.
2. Implementation fsck's recovering functionality.

Currently, all my efforts is in direction of implementation fsck's
checking functionality. I think that next immediate step should be
preliminary definition of fsck's architecture, a strategy of fsck's
checking algorithm, discussion of it and declaration of functions' stub
in code.

I am going to elaborate more clear preliminary vision of fsck's checking
functionality during next two weeks (maybe earlier :-)). But, currently
and preliminary, I am thinking about several phases (passes) of check:
1. Check superblocks.
2. Check correctness of metadata in logs.
3. Check correctness of metadata files' contents for segments.
4. Check consistency of file system hierarchy.

This is a really raw and preliminary vision. I feel real necessity to
think more deeply about it. And elaboration of such more clear vision is
my current implementation activities. I am going to elaborate the vision
during implementation of superblocks checking functionality.

With the best regards,
Vyacheslav Dubeyko.

> My concern for this is avoiding rework of the future.
> 
> I'm very thankful for your challenges.
> 
> With regards,
> Ryusuke Konishi
> 
> > --
> >  configure.ac     |    3 ++-
> >  sbin/Makefile.am |    2 +-
> >  2 files changed, 3 insertions(+), 2 deletions(-)
> > 
> >  sbin/fsck/Makefile.am        |   13 ++
> >  sbin/fsck/fsck_messages.c    |  254 ++++++++++++++++++++++++
> >  sbin/fsck/fsck_messages.def  |   62 ++++++
> >  sbin/fsck/fsck_messages.h    |  110 +++++++++++
> >  sbin/fsck/fsck_nilfs2.c      |  379 +++++++++++++++++++++++++++++++++++
> >  sbin/fsck/fsck_nilfs2.h      |   37 ++++
> >  sbin/fsck/fsck_raw_ops.c     |  413 +++++++++++++++++++++++++++++++++++++++
> >  sbin/fsck/fsck_raw_ops.h     |   46 +++++
> >  sbin/fsck/nilfs_superblock.c |  445 ++++++++++++++++++++++++++++++++++++++++++
> >  sbin/fsck/nilfs_superblock.h |   48 +++++
> >  10 files changed, 1807 insertions(+), 0 deletions(-)
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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