The buffer I/O accounting mechanism tracks async buffers under I/O. As an optimization, the buffer I/O count is incremented only once on the first async I/O for a given hold cycle of a buffer and decremented once the buffer is released to the LRU (or freed). xfs_buf_ioacct_dec() has an ASSERT() check for an XBF_ASYNC buffer, but we have one or two corner cases where a buffer can be submitted for I/O multiple times via different methods in a single hold cycle. If an async I/O occurs first, the I/O count is incremented. If a sync I/O occurs before the hold count drops, XBF_ASYNC is cleared by the time the I/O count is decremented. Remove the async assert check from xfs_buf_ioacct_dec() as this is a perfectly valid scenario. For the purposes of I/O accounting, we really only care about the buffer async state at I/O submission time. Discovered-and-analyzed-by: Dave Chinner <david@xxxxxxxxxxxxx> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx> --- fs/xfs/xfs_buf.c | 1 - 1 file changed, 1 deletion(-) diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 32fc540..b13ff61 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -115,7 +115,6 @@ xfs_buf_ioacct_dec( if (!(bp->b_flags & _XBF_IN_FLIGHT)) return; - ASSERT(bp->b_flags & XBF_ASYNC); bp->b_flags &= ~_XBF_IN_FLIGHT; percpu_counter_dec(&bp->b_target->bt_io_count); } -- 2.5.5 _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
