lkml.org 
[lkml]   [2004]   [Aug]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: silent semantic changes with reiser4
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1



Christophe Saout wrote:

| Yes, the main compound stream unaware applications would see would just
| be a writable view of its contents. Probably not trivial to implement
| but doable.

Not the main stream, I think, but we do need a way to make "eight-stream
octopus" files portable. But there needs to be a copy(2) syscall, and
apps need to start supporting it. After all, copy-on-write was planned
for Reiser4, now 4.1*. And don't anyone dare suggest "userland library".

| It should be a simple format. Something simliar to tar. The worst thing

Simple, yes. Similar to tar, no.

How about a serializer plugin? foo.mp3/serialize (say) should return
some single stream which contains all of foo.mp3. It could work for
directories as well, recursively, at least on the same filesystem --
you'd back up by doing

cp /serialize /backup/20040826

This has two potential problems. One is security -- I want to be able
to serialize foo.mp3 without being root, but root doesn't want me to be
able to serialize /etc and thus get access to shadow.

The second problem is that in order to actually be used for backup, we
need snapshots, which are not done yet*. Currently, it'd have to lock
the file/directory (recursively), which you don't want to do to entire
live filesystems... So, no massive backups of live systems yet, but
definitely useful for sending around mp3s and such.

| that can happen is people start writing plugins for every existing
| compound format out there. It should be the other way around, agree on a
| simple compound format and encourage applications to use this one if the
| want to use this advantage.

For the format, I vote for whatever format we're using at the storage
layer. It'd be a lot faster that way, both in execution time (I think)
and in development time (I'm sure). Plus, imagine the restore:

cat /backup/20040826 > /dev/hda5
resizefs_reiser4 /dev/hda5


* Disclaimer -- all this is "I think, last I checked".


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org
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=7bBF
-----END PGP SIGNATURE-----
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:05    [W:0.881 / U:0.276 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site