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Jaegeuk Kim authored
We have a node chain to serialize node block writes, so if any IOs for node block writes are reordered, we'll get broken node chain. IOWs, roll-forward recovery will see all or none node blocks given fsync mark. E.g., Node chain consists of: N1 -> N2 -> N3 -> NFSYNC -> N1' -> N2' -> N'FSYNC Reordered to: 1) N1 -> N2 -> N3 -> N2' -> NFSYNC -> N'FSYNC -> power-cut 2) N1 -> N2 -> N3 -> N1' -> NFSYNC -> power-cut 3) N1 -> N2 -> NFSYNC -> N1' -> N'FSYNC -> N3 -> power-cut 4) N1 -> NFSYNC -> N1' -> N2' -> N'FSYNC -> N3 -> power-cut Roll-forward recovery can proceed to: 1) N1 -> N2 -> N3 -> NFSYNC -> X 2) N1 -> N2 -> N3 -> NFSYNC -> N1' -> X 3) N1 -> N2 -> N3 -> FSYNC -> N1' -> X 4) N1 -> X Signed-off-by:
Jaegeuk Kim <jaegeuk@kernel.org>
b6a245eb