Cc: Andrew Morton <akpm@...>, Chris Mason <chris.mason@...>, Christian Borntraeger <borntraeger@...>, <linux-mm@...>, <linux-kernel@...>, Martin Schwidefsky <schwidefsky@...>, Theodore Ts'o <tytso@...>, <stable@...>
Well tools like dump certainly weren't happy when we made the change.
Well my goal with separating things is so that we could decouple two
pieces of code that have different usage scenarios, and where
supporting both scenarios simultaneously appears to me to needlessly
complicate the code.
Added to that we could then tune the two pieces of code for their
different users.
ext2 doesn't store directories in the buffer cache.
Journaling filesystems and filesystems that do ordered writes
game the buffer cache. Putting in data that should not yet
be written to disk. That gaming is where reiserfs goes BUG
and where JBD moves the dirty bit to a different dirty bit.
So as far as I can tell what is in the buffer cache is not really
in sync with what should be on disk at any given movement except
when everything is clean.
My suspicion is that actually reading from disk is likely to
give a more coherent view of things. Because there at least
we have the writes as they are expected to be seen by fsck
to recover the data, and a snapshot there should at least
be recoverable. Whereas a snapshot provides not such guarantees.
Eric
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