Re: keys and inodes

[Marcelo Pacheco <marcelo@macp.eti.br>]

So, inode numbers on Reiser are alocated on the fly, as files are used, and 
those numbers will change, so for example, ls -i is useless with reiser, as 
that number given for each file will change once the vfs structure gets 
released and later the file gets used again ?

Just checking,

Marcelo Pacheco

On Saturday 03 July 2004 06:28, Vladimir V. Saveliev wrote:
> Hello
>
> jenn sirp wrote:
> > Hi,
> >
> > I was hoping someone might be able to answer a couple of questions about
> > inodes is Reiser(v3).
> >
> > I would like to know how ReiserFS inodes and the VFS inodes in the
> > d_cache correspond with each other.
>
> You might want to read about dentry-inode relationship in
> linux/Documentation/filesystem/vfs.txt.
>
>   Specifically, how and where it is
>
> > that 'keys' get mapped to inodes in the system?
>
> Reiserfs provides set of vfs operations. The one which is responsible
> for mapping keys to inode is lookup method. reiserfs implementation is
> reiserfs_lookup. It searches for the file name in filesystem tree. If
> name is found - file key is extracted from it and VFS inode is created
> (connected to d_cache dentry).
> File key is stored in reiserfs specific portion of VFS inode.
>
> > Do ReiserFS keys change or get reconstructed when tails are packed or
> > when the tree gets re-balanced?
>
> No. Once file is created - its key never changes. However, each position
> in a file has its own key. For instance, 0-th byte of a file has key X,
> Y, 1. 100-th byte of a file should be looked for with key X, Y, 101.
> [X, Y] is the same for any part of file. This is what is extracted from
> file name on lookup. Key of any other position within a file can be
> easily calculated as we saw.
>
> Or do keys remain consistent throughout
>
> > a file's lifetime in the system?
>
> Yes.
>
> > Even the quickest response would be greatly appreciated.
> >
> > Thanks,
> >
> > Jenn