Extracting changed files list from snapshot
Mel
fbsd.questions at rachie.is-a-geek.net
Thu Dec 18 07:26:52 UTC 2008
On Wednesday 17 December 2008 11:37:04 Bernard Dugas wrote:
> Mel wrote:
> > On Tuesday 16 December 2008 15:18:19 Bernard Dugas wrote:
> >>I want to extract the list of files changed between 2 snapshots, to be
> >>able to do efficient backups.
<snip>
> > And what snapshots do you mean? As in mksnap_ffs? Cause that's described
> > in /usr/src/sys/ufs/ffs/ffs_snapshot.c:
> > 127 TAILQ_HEAD(snaphead, inode);
> > 128
> > 129 struct snapdata {
> > 130 struct snaphead sn_head;
> > 131 daddr_t sn_listsize;
> > 132 daddr_t *sn_blklist;
> > 133 struct lock sn_lock;
> > 134 };
> > 135
> >
> > and not exposed to userland.
>
> Thanks, this is a good hint ! Just needing some doc and help to
> understand how to use it : i'm more in design now, programmation skills
> are far away :-(
I'm still wondering if you're not better off with ZFS, but this does seem like
a useful app in it's own right.
The TAILQ_HEAD statement means it's creating a tail queue(3) (double linked
fifo/stack) of inodes. The snapdata structure contains the start of the list,
the size and a lock. The sn_blklist pointer, I will have to look up.
I think i'm gonna have fun with this for a bit ;)
--
Mel
Problem with today's modular software: they start with the modules
and never get to the software part.
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