"umount: / is busy"

[Russell Coker]

On Monday 08 August 2005 16:21, Florin Andrei <florin at andrei.myip.org> wrote:
> On Mon, 2005-08-08 at 02:44 +0200, Ralf Ertzinger wrote:
> > Sometimes, after a "yum upgrade", I get a message on shutdown saying that
> > / is busy and can not be unmounted, leading to a filesystem check on the
> > next reboot (or better: a journal replay). So far I have not been able to
> > figure out what exactly causes this.
>
> I noticed that it seems to always happen when upgrading glibc, but
> perhaps other packages too can trigger it.
>
> It is the reason why I pretty much always do "sync" before "reboot",
> "halt" or "poweroff".
> It would be nice if "sync" was included in the system scripts, right
> before doing umount.

Below is the relevant section from the source of /sbin/shutdown.  halt also 
calls sync() so there's no need for scripts to do such things.

  sync();
  fprintf(stderr, "shutdown: turning off swap\r\n");
  spawn(0, "swapoff", "-a", NULL);
  fprintf(stderr, "shutdown: unmounting all file systems\r\n");
  spawn(0, "umount", "-a", NULL);

  /* We're done, halt or reboot now. */
  if (do_halt) {
        fprintf(stderr, "The system is halted. Press CTRL-ALT-DEL or turn off 
power\r\n");
        init_reboot(BMAGIC_HALT);
        exit(0);
  }
  fprintf(stderr, "Please stand by while rebooting the system.\r\n");
  init_reboot(BMAGIC_REBOOT);
  exit(0);


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