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Viewing changes to DistUpgrade/DistUpgradeController.py

  • Committer: Michael Vogt
  • Date: 2009-01-07 15:44:37 UTC
  • Revision ID: michael.vogt@ubuntu.com-20090107154437-wnd205g2nc4t0gyx
DistUpgrade/DistUpgradeController.py: ensure that varrun and varlock keep working when the aufs overlay is done

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DistUpgrade/DistUpgradeController.py
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                return False
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        return True
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    # FIXME: this is currently run *after* /var/log/dist-upgrade/main.log
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    #        is opened and its not in the aufs file    
 
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    def _bindMount(self, from_dir, to_dir):
 
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        " helper that bind mounts a given dir to a new place "
 
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        if not os.path.exists(to_dir):
 
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            os.makedirs(to_dir)
 
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        cmd = ["mount","--bind", from_dir, to_dir]
 
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        res = subprocess.call(cmd)
 
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        if res != 0:
 
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            # FIXME: revert already mounted stuff
 
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            logging.error("Failed to bind mount from '%s' to '%s'" % (from_dir, to_dir))
 
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            return False
 
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        return True
 
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    def _aufsOverlayMount(self, target, rwdir):
 
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        """ 
 
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        helper that takes a target dir and mounts a rw dir over it, e.g.
 
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        /var , /tmp/upgrade-rw
 
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        """
 
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        if not os.path.exists(rw_dir+target):
 
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            os.makedirs(rw_dir+target)
 
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        cmd = ["mount",
 
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               "-t","aufs",
 
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               "-o","br:%s:%s=ro" % (rw_dir+target, target),
 
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               "none",
 
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               d,]
 
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        res = subprocess.call(cmd)
 
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        if res != 0:
 
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            # FIXME: revert already mounted stuff
 
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            logging.error("Failed to mount rw aufs overlay for '%s'" % target)
 
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            return False
 
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        return True
 
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    def setupAufs(self):
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        " setup aufs overlay "
 
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        # FIXME: this is currently run *after* /var/log/dist-upgrade/main.log
 
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        #        is opened and its not in the aufs file    
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        logging.debug("setupAufs")
 
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        rw_dir = self.aufs_rw_dir
 
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        # aufs mounts do not support stacked filesystems, so
 
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        # if we mount /var we will loose the tmpfs stuff
 
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        # first bind mount varun and varlock into the tmpfs
 
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        tmpfses = ["/var/run","/var/lock"]
 
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        for d in tmpfses:
 
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            if not self._bindMount(d, rw_dir+"/tmpfs/"+d):
 
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                return False
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        # setup writable overlay into /tmp/upgrade-rw so that all 
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        # changes are written there instead of the real fs
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        rw_dir = self.aufs_rw_dir
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        for d in ["/bin","/boot","/etc","/lib","/sbin","/usr","/var"]:
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            if not os.path.exists(rw_dir+d):
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                os.makedirs(rw_dir+d)
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            cmd = ["mount",
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                   "-t","aufs",
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                   "-o","br:%s:%s=ro" % (rw_dir+d, d),
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                   "none",
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                   d,]
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            res = subprocess.call(cmd)
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            if res != 0:
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                # FIXME: revert already mounted stuff
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                logging.error("Failed to mount %s with aufs" % d)
 
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            if not self._aufsOverlayMount(d, rw_dir):
 
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                return False
 
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        # now bind back the tempfs to the original location
 
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        for d in tmpfses:
 
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            if not self._bindMount(rw_dir+"/tmpfs/"+d, d):
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                return False
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        # FIXME: now what we *could* do to apply the changes is to
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        #        mount -o bind / /orig