cvs commit: src/sys/fs/nullfs null.h null_subr.c null_vnops.c

[Tim J. Robbins]

tjr         2003/06/17 01:52:45 PDT

  FreeBSD src repository

  Modified files:
    sys/fs/nullfs        null.h null_subr.c null_vnops.c 
  Log:
  MFp4: Fix two bugs causing possible deadlocks or panics, and one nit:
  - Emulate lock draining (LK_DRAIN) in null_lock() to avoid deadlocks
    when the vnode is being recycled.
  - Don't allow null_nodeget() to return a nullfs vnode from the wrong
    mount when multiple nullfs's are mounted. It's unclear why these checks
    were removed in null_subr.c 1.35, but they are definitely necessary.
    Without the checks, trying to unmount a nullfs mount will erroneously
    return EBUSY, and forcibly unmounting with -f will cause a panic.
  - Bump LOG2_SIZEVNODE up to 8, since vnodes are >256 bytes now. The old
    value (7) didn't cause any problems, but made the hash algorithm
    suboptimal.
  
  These changes fix nullfs enough that a parallel buildworld succeeds.
  
  Submitted by:   tegge (partially; LK_DRAIN)
  Tested by:      kris
  
  Revision  Changes    Path
  1.19      +2 -0      src/sys/fs/nullfs/null.h
  1.41      +36 -9     src/sys/fs/nullfs/null_subr.c
  1.63      +57 -4     src/sys/fs/nullfs/null_vnops.c