[Mageia-dev] Planning the /usr move

Wed Jul 11 15:01:31 CEST 2012

'Twas brillig, and Olav Vitters at 11/07/12 13:39 did gyre and gimble:
+> On Wed, Jul 11, 2012 at 12:52:17PM +0100, Colin Guthrie wrote:
+>>  2. Add a patch to RPM that introduces a new check that must pass before
+>> a given RPM can be installed.
+>>  3. Create a new "filesystem" build that uses this check.
+> [..]
+>> Several other packages will be subsequently broken (some packages ship
+>> their binaries in /bin but symlink them to /usr/bin  but when /bin is
+>> itself a symlink to /usr/bin, they package ultimately conflicts with
+>> itself!). We need to identify such packages and fix them and have them
+>> ready to go. In order to do the transition correctly, we may need to fix
+>> them first, build them and then wait until all such packages are fixed,
+>> THEN update the filesystem rpm and then rebuild all such packages with a
+>> dep on the filesystem > x package. This might be needed to avoid any
+>> problems on the build system chroots.
+> 
+> Shouldn't those packages also rely on the new RPM check? Or you mean
+> just update those packages and don't allow for symlinks between /bin and
+> /usr/bin (+same for sbin)?
+
+They don't need to. Provided they "Require(pre): filesystem >= foo" and
+rely on the check being in filesystem rpm packge. That prevents too many
+"quirks" being in too many packages (the error message would also be
+more confusing for users but a simple "I need a newer filesystem
+package" is a bit clearer.
+
+> Would the new RPM do a runtime check to see if things have been
+> migrated?
+
+Yes, this is what the patch does, but as mentioned it would only be the
+"filesystem" rpm that would actually implement this check.
+
+> Does Dracut usrmove handle the packages which at the moment contain
+> symlinks (e.g. /bin/foo -> /usr/bin/foo and e.g. /usr/bin/bar ->
+> /bin/bar)? Or should either dracut or the packages have conflicts to
+> deal with this?
+
+The code in dracut deals with this currently. It will overwrite symlinks
+with the real binary instead.
+
+The code is actually quite simple:
+
+/usr/lib/dracut/modules.d/30convertfs/convertfs.sh
+
+
+There may be some junk left behind when packages provide separate
+binaries of the same name in /bin vs /usr/bin (and sbin), but this is
+relatively rare (although I will mention this more in my next message).
+
+Col
+
+
+
+
+-- 
+
+Colin Guthrie
+colin(at)mageia.org
+http://colin.guthr.ie/
+
+Day Job:
+  Tribalogic Limited http://www.tribalogic.net/
+Open Source:
+  Mageia Contributor http://www.mageia.org/
+  PulseAudio Hacker http://www.pulseaudio.org/
+  Trac Hacker http://trac.edgewall.org/
+
+
+