Hi Andreas, hi Ryusuke, > Instead of periodically writing to the super block, this patch only > writes at mount and umount time and performs a linear scan for the > latest segment in case a recovery is necessary. > The SD-Cards and the USB-Stick are not particularly fast, but they are > small enough so that the recovery time is tolerable. Finally I found some time to test your patch and also the new version works fine (and fast!) here: [ 3.349464] NILFS warning: searching for latest log [ 4.747552] NILFS warning: mounting unchecked fs [ 5.214883] NILFS: recovery complete. So your enhanced recovery code requires ~1.3s for a 12GB nilfs2 partition on the higher-end 16GB SD card I use in the raspberry. Also, despite frequent power-cuts I haven't obsereved any issues - which made me switch to nilfs2+patch even for the rootfs (was ext4 ro). > I see. For further discussion on this approach, it looks like we need > some measurement data of the situation that this patch makes a > difference (for example, for an SD card or some device). Anyway, I > agree that the patch has a value for experiment purpose. What do you think about the results obtained by andreas and me? With SD cards (in the raspberry) I experience linear scan times as low as ~110ms/1GB, and for everything else avoiding superblock writes probably doesn't make sense anyway. And if some techie enables the option on his SSD, recovery is also blazingly fast. Thanks a lot & best regards, Clemens -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
