Re: [Dump-users] QFA for disk file wrong?

[Stelian P. <st...@po...>]

Le mardi 27 mai 2008 à 16:57 -0700, Kenneth Porter a écrit :
> On Tuesday, May 27, 2008 4:47 PM -0700 Kenneth Porter 
> <sh...@se...> wrote:
> 
> > Note the repeated inode. I'm running a find right now to find the file
> > with  that inode.
> 
> The file is a PNG in some doxygen output. All of the other files in that 
> directory have identical labeling (as listed by "ls --scontext").

[...]

> All the duplicates have 2 copies, no more.

Normal: there is one copy for the inode, and another one for the
extended attributes header.

>  So almost 9000 dups in 551790 
> files.

And it is also normal to have duplicates only for some inodes. The QFA
file does not contain the position for _all_ the inodes, only some of
them (the position is saved once per ntrec - meaning once per 64 * 1024
bytes -, when a start header - inode _or_ EA - is seen in the output
stream). This means that the duplicates appear only in some cases. For
example, if an x count for 8kb, a and b are inodes, A and B are the
extended attributes of a and b):

	xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
	aaaaaaaA Abbbbbbb bbbbBcCd dddddddD

QFA:    ^         ^           ^           ^

In the example above, only b/B will generate duplicates.

The simplest way to correct this would be to modify dump in order to
forbid the creation of QFA positions for EAs, only for real inodes. But
I need to think a bit if there isn't something we can do to cope with
those duplicates in restore (to handle QFA files generated by an older
version of dump).

Let me think a bit about this and I'll propose you a patch.

> I'm running SELinux in Permissive mode. Could dump get confused if I have 
> it on but not enforcing?

No, this is not related.

Stelian.
-- 
Stelian Pop <st...@po...>