cvs commit: src/sys/vm vm_fault.c

Pawel Jakub Dawidek pjd at
Thu Apr 5 20:49:47 UTC 2007

pjd         2007-04-05 20:49:46 UTC

  FreeBSD src repository

  Modified files:
    sys/vm               vm_fault.c 
  Fix a problem for file systems that don't implement VOP_BMAP() operation.
  The problem is this: vm_fault_additional_pages() calls vm_pager_has_page(),
  which calls vnode_pager_haspage(). Now when VOP_BMAP() returns an error (eg.
  EOPNOTSUPP), vnode_pager_haspage() returns TRUE without initializing 'before'
  and 'after' arguments, so we have some accidental values there. This bascially
  was causing this condition to be meet:
          if ((rahead + rbehind) >
              ((cnt.v_free_count + cnt.v_cache_count) - cnt.v_free_reserved)) {
  (we have some random values in rahead and rbehind variables)
  I'm not entirely sure this is the right fix, maybe we should just return FALSE
  in vnode_pager_haspage() when VOP_BMAP() fails?
  alc@ knows about this problem, maybe he will be able to come up with a better
  fix if this is not the right one.
  Revision  Changes    Path
  1.226     +2 -0      src/sys/vm/vm_fault.c

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