Do dirty page accounting when removing a page from the page cache

Do dirty page accounting when removing a page from the page cache

Krzysztof Oledzki noticed a dirty page accounting leak on some of his
machines, causing the machine to eventually lock up when the kernel
decided that there was too much dirty data, but nobody could actually
write anything out to fix it.

The culprit turns out to be filesystems (cough ext3 with data=journal
cough) that re-dirty the page when the "->invalidatepage()" callback is
called.

Fix it up by doing a final dirty page accounting check when we actually
remove the page from the page cache.

This fixes bugzilla entry 9182:

	http://bugzilla.kernel.org/show_bug.cgi?id=9182

Tested-by: Ingo Molnar <[email protected]>
Tested-by: Krzysztof Oledzki <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>