readahead: fix NULL filp dereference
authorWu Fengguang <fengguang.wu@intel.com>
Tue, 6 Apr 2010 21:34:53 +0000 (14:34 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 7 Apr 2010 15:38:03 +0000 (08:38 -0700)
commit70655c06bd3f25111312d63985888112aed15ac5
treee6db465a10b6ece8f50fbcfce97404f03044e248
parent12765517d9dbb477a2432375938f1eb5bdbcb532
readahead: fix NULL filp dereference

btrfs relocate_file_extent_cluster() calls us with NULL filp:

  [ 4005.426805] BUG: unable to handle kernel NULL pointer dereference at 00000021
  [ 4005.426818] IP: [<c109a130>] page_cache_sync_readahead+0x18/0x3e

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Yan Zheng <yanzheng@21cn.com>
Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Tested-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/readahead.c