cvs commit: src/sys/vm vm_map.c src/sys/vfs/ufs ufs_readwrite.c

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxxxxx>]

dillon      2004/04/22 23:23:46 PDT

DragonFly src repository

  Modified files:
    sys/vm               vm_map.c 
    sys/vfs/ufs          ufs_readwrite.c 
  Log:
  msync(..., MS_INVALIDATE) will incorrectly remove dirty pages without
  synchronizing them to their backing store under certain circumstances,
  and can also cause struct buf's to become inconsistent.  This can be
  particularly gruesome when MS_INVALIDATE is used on a range of memory that
  is mmap()'d to be read-only.
  
  Fix MS_INVALIDATE's operation (1) by making UFS honor the invalidation
  request when flushing to backing store to destroy the related struct buf
  and (2) by never removing pages wired into the buffer cache and never
  removing pages that are found to still be dirty.
  
  Note that NFS was already coded to honor invalidation requests in
  nfs_write().  Filesystems other then NFS and UFS do not currently support
  buffer-invalidation-on-write but all that means now is that the pages
  will remain in cache, rather then be incorrectly removed and cause corruption.
  
  Reported-by: Stephan Uphoff <ups@xxxxxxxx>, Julian Elischer <julian@xxxxxxxxxxxx>
  
  Revision  Changes    Path
  1.25      +1 -1      src/sys/vm/vm_map.c
  1.10      +2 -0      src/sys/vfs/ufs/ufs_readwrite.c


http://www.dragonflybsd.org/cvsweb/src/sys/vm/vm_map.c.diff?r1=1.24&r2=1.25&f=h
http://www.dragonflybsd.org/cvsweb/src/sys/vfs/ufs/ufs_readwrite.c.diff?r1=1.9&r2=1.10&f=h