From d624c96fb3249e5d3dcf4e60a805e5e6b0dd7d91 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 2 Nov 2012 17:13:32 +0900 Subject: [PATCH] f2fs: add recovery routines for roll-forward This adds roll-forward routines to recover fsynced data. - F2FS uses basically roll-back model with checkpointing. - In order to implement fsync(), there are two approaches as follows. 1. A roll-back model with checkpointing at every fsync() : This is a naive method, but suffers from very low performance. 2. A roll-forward model : F2FS adopts this model where all the fsynced data should be recovered, which were written after checkpointing was done. In order to figure out the data, F2FS keeps a "fsync" mark in direct node blocks. In addition, F2FS remains the location of next node block in each direct node block for reconstructing the chain of node blocks during the recovery. - In order to enhance the performance, F2FS keeps a "dentry" mark also in direct node blocks. If this is set during the recovery, F2FS replays adding a dentry. Signed-off-by: Jaegeuk Kim --- Reading git-format-patch failed