> > In the fast commit, it adds REQ_FUA and REQ_PREFLUSH on each fast commit > > block when barrier is enabled. However, in recovery phase, ext4 compares > > CRC value in the tail. So it is sufficient adds REQ_FUA and REQ_PREFLUSH > > on the block that has tail. > > Does the tail block *always* contain a CRC, or is that dependent on > EXT4_FEATURE_RO_COMPAT_METADATA_CSUM, JBD2_FEATURE_INCOMPAT_CSUM_V2, > or JBD2_FEATURE_INCOMPAT_CSUM_V3 being enabled? In the fast commit, the tail block always contain a CRC. > If one of those features is *required* before the FAST_COMMIT feature > can be used, then this patch looks OK. Otherwise, the CSUM feature > should be checked before the FUA is skipped for non-tail blocks. So, I think it is OK without checking other CSUM feature. Thanks, Daejun
