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RE: newbie to JFFS2



Thanks Mr. Artem. Please excuse me if I am asking too obvious questions.

1) I have a requirement in my software to make the filesystem self 
   referential. For this I had gone thro' JFFS source code and also
JFFS2 
   source code. But the problem is that the filename representations are

   made in the RAM based structures rather than the in flash data 
   structures. How is the File System getting the Filename while it is
being 
   built in JFFS? In our design we are not particular to support
hardlinks.

2) What I meant by versioning is the version for each file (e.g., CVS)
being 
   stored on the file system. If anybody can give me a case study of how

   they have done this, might be very useful to me. 

3) Does www.embeddedlinuxworks.com still exists or has it relocated? 

With Regards,
C.R.Srivatsan




-----Original Message-----
From: Artem B. Bityuckiy [mailto:dedekind@xxxxxxx.org] 
Sent: Monday, March 28, 2005 12:31 PM
To: Srivatsan
Cc: jffs-dev@xxxxxxx.com
Subject: Re: newbie to JFFS2

On Sun, 2005-03-27 at 17:18 +0530, Srivatsan wrote:
> Dear all,
> 
>     I am new to the concept of Flash File System. I had gone thro' the
> JFFS2 white paper and to an extent the source code of JFFS2. I have
the
> following doubt:
> 
> 1) I am seeing that the filenames are not being stored along with the
> inode but with dentry nodes? If I want to make nodes self referential
> (inode number and filename in the same raw inode structure), is it
> possible? I was trying to go thro' the JFFS source, but their again
the
> file names are not stored in the JFFS_raw_inode structure (but in the
> white paper it is mentioned that filenames are stored along with the
> metadata). Can anyone please clarify exactly how filenames are being
> handled in JFFS2? Really it would be a great help to me.
There is a model sometimes called "VFS model" where data is represented
by means of inode objects while names are represented by directory
entries. Inodes contain all the file's (direcory's) data and metadata
(permissions, etc). One inode may be referred by several directory
entries and this allows us to have hardlinks. And this is common model,
not JFFS2-specific.

Do you want to join them? Then you'll end up with FAT which is avoid of
hardlinks.

> 
> 2) Is anyone using versioning alongwith JFFS2? If so, have you
modified
> the exisiting JFFS2 source or are you using concepts like stackable
file
> system to achieve your requirements? If possible, can you experience
be
> shared.
I'm not sure I understand your question. Versions are the crucial part
of JFFS2 and JFFS2 design. Versions are invisible for users and are an
element of internal JFFS2 design.


-- 
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.




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