Re: 2.5.59-mm5

Alex Tomas
2003-01-24T19:58:13Z

>>>>> Andrew Morton (AM) writes:

AM> We cannot free disk blocks until I/O against them has completed.
AM> Otherwise the block could be reused for something else, then the
AM> old IO will scribble on the new data.

AM> What we _can_ do is to defer the waiting - only wait on the I/O
AM> when someone reuses the disk blocks. So there are actually
AM> unused blocks with I/O in flight against them.

AM> We do that for metadata (the wait happens in
AM> unmap_underlying_metadata()) but for file data blocks there is no
AM> mechanism in place to look them up

yeah! indeed. my stupid mistake ...