cvs commit: src/sys/kern vfs_cache.c vfs_subr.c src/sys/sys namecache.h

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxxxxx>]

dillon      2005/02/12 10:56:47 PST

DragonFly src repository

  Modified files:
    sys/kern             vfs_cache.c vfs_subr.c 
    sys/sys              namecache.h 
  Log:
  Fix a cache_resolve() vs cache_inval() race which can result in a livelock.
  The namecache invalidation code was being a bit overzealous when asked to
  invalidate a subhierarchy.  It was retrying until the subhierarchy was
  completely invalidated, re-invalidating new entries created after the initial
  call to cache_inval().  This can occur if the filesystem is heavily loaded
  and a high level directory is being recursively invalidated.
  
  It is unnecessary to retry in this case... the purpose is to invalidate
  as-of the call to cache_inval(), so it is acceptable to allow new entries
  to be resolved within the subhierarchy undergoing the invalidation.
  
  Certain higher level entities... rename, and vnode reclamation, require
  complete invalidation.  The retry has been moved to a higher level for
  these entities.  The basic cache_inval() code is now single-pass.
  
  Reported-by: Richard Nyberg <rnyberg@xxxxxxxx>
  
  Revision  Changes    Path
  1.51      +52 -16    src/sys/kern/vfs_cache.c
  1.52      +4 -1      src/sys/kern/vfs_subr.c
  1.19      +2 -2      src/sys/sys/namecache.h


http://www.dragonflybsd.org/cvsweb/src/sys/kern/vfs_cache.c.diff?r1=1.50&r2=1.51&f=u
http://www.dragonflybsd.org/cvsweb/src/sys/kern/vfs_subr.c.diff?r1=1.51&r2=1.52&f=u
http://www.dragonflybsd.org/cvsweb/src/sys/sys/namecache.h.diff?r1=1.18&r2=1.19&f=u