git: DragonFly_RELEASE_5_4 kernel - Fix rare vref() assertion

[Matthew Dillon]

commit edfbaa6878e6f90fe3cf3c65b16bf04973b04f91
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date:   Sat Dec 8 14:34:51 2018 -0800

    kernel - Fix rare vref() assertion
    
    * The VREF_TERMINATE flag gets cleared when a vnode is reactivated.
      However, concurrent LK_SHARED locks on vnodes can race the v_state
      test.  Thus the code cannot assume that VREF_TERMINATE has been cleared
      when v_state is VS_ACTIVE.
    
      To avoid the race, we simply unconditionally clear VREF_TERMINATE on
      a successful vget().
    
    * Could be reproduced by running blogbench and synth together, both of
      which generate extreme filesystem-intensive loads.

Summary of changes:
 sys/kern/vfs_lock.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/edfbaa6878e6f90fe3cf3c65b16bf04973b04f91


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