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Date: Mon, 14 Apr 1997 03:52:30 -0700 (PDT)
From: KATO Takenori <kato>
Message-Id: <199704141052.DAA03381@freefall.freebsd.org>
To: CVS-committers, cvs-all, cvs-sys
Subject: cvs commit:  src/sys/miscfs/union union_vfsops.c
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kato        97/04/14 03:52:29

  Modified:    sys/miscfs/union  union_vfsops.c
  Log:
  Fix `lockmgr: locking against myself' panic by multi union mount of
  same directory pair.
  
  If we do:
      mount -t union a b
      mount -t union a b
  then, (1) namei tries to lock fs which has been already locked by
  first union mount and (2) union_root() tries to lock locked fs.  To
  avoid first deadlock condition, unlock vnode if lowerrootvp is union
  node, and to avoid second case, union_mount returns EDEADLK when multi
  union mount is detected.
  
  Revision  Changes    Path
  1.15      +25 -1     src/sys/miscfs/union/union_vfsops.c