Re: 2.5.59-mm5

[Alex Tomas <bzzz@tmi.comex.ru>]

>>>>> 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 ...




--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/