ocfs2: don't use iocb when EIOCBQUEUED returns

When -EIOCBQUEUED returns, it means that aio_complete() will be called
from dio_complete(), which is an asynchronous progress against
write_iter.  Generally, IO is a very slow progress than executing
instruction, but we still can't take the risk to access a freed iocb.

And we do face a BUG crash issue.  Using the crash tool, iocb is
obviously freed already.

  crash> struct -x kiocb ffff881a350f5900
  struct kiocb {
    ki_filp = 0xffff881a350f5a80,
    ki_pos = 0x0,
    ki_complete = 0x0,
    private = 0x0,
    ki_flags = 0x0
  }

And the backtrace shows:
  ocfs2_file_write_iter+0xcaa/0xd00 [ocfs2]
  aio_run_iocb+0x229/0x2f0
  do_io_submit+0x291/0x540
  SyS_io_submit+0x10/0x20
  system_call_fastpath+0x16/0x75

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Changwei Ge <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Joseph Qi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions