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Re: Max Mount Count

Ted writes:
> The patches for 2.2 LVM/ext3 to do read-only snapshots already exist,
> and I believe have been folded into the LVM CVS tree; the hooks in the
> ext3 code have been there since 0.6a or so.  

Only partially.  Stephen added code to ext3-0.0.6 to do a full journal
flush, but the actual LVM functions (write_super_lockfs, unlockfs) are
not in either of the 2.2 or 2.4 code.  I have added these functions to
my 2.4 kernel tree, but have not yet tested it.

> There are some weird LVM bugs which our NAS folks have been trying to
> figure out, but it seems pretty clear they are LVM bugs and not ext3
> issues.  

Yes, I read about that, but haven't had a chance to look into it (I
rarely play with snapshots, so it doesn't affect me).  However, there
are already some known problems with snapshots that the IBM folks have
brought up (namely removing a PV from a VG will break snapshots, even
if that PV is not used by the snapshot).  It may be a related issue
(i.e. PV numbering for multi-PV snapshots is broken).

Cheers, Andreas
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert

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