On Jan 30, 2014, at 9:02 AM, Andreas Rohner wrote: > Hi Vyacheslav, > > On 2014-01-30 07:36, Vyacheslav Dubeyko wrote: >> Hi Andreas, >> >> On Jan 30, 2014, at 5:47 AM, Andreas Rohner wrote: >> >>> This patch introduces a mount option bad_ftl that disables the >>> periodic overwrites of the super block to make the file system better >>> suitable for bad flash memory with a bad FTL. The super block is only >>> written at umount time. So if there is a power outage the file system >>> needs to be recovered by a linear scan of all segment summary blocks. >>> >>> The linear scan is only necessary if the file system wasn't umounted >>> properly. So the normal mount time is not affected. >>> >>> Signed-off-by: Andreas Rohner <andreas.rohner@xxxxxxx> >>> --- >>> fs/nilfs2/segbuf.c | 3 ++- >>> fs/nilfs2/segment.c | 3 ++- >>> fs/nilfs2/super.c | 10 +++++++-- >>> fs/nilfs2/the_nilfs.c | 54 ++++++++++++++++++++++++++++++++++++++++++++--- >>> include/linux/nilfs2_fs.h | 4 +++- >>> 5 files changed, 66 insertions(+), 8 deletions(-) >>> >> >> As far as I can judge, conceptually it is simply rollback of the fix [1]. > > The normal recovery mode checks all partial segments and computes the > checksum over all the data. That takes significantly longer than my > approach of just checking one block per segment, namely the segment > summary block. > I don't think that your suggestion changes situation significantly. Because in the issue [1] you can go through the whole volume in the really bad environment. Maybe you will mount volume 30 minutes instead of 1 hour with technique that you suggest in the patch. With the best regards, Vyacheslav Dubeyko. > br, > Andreas Rohner > >> Thanks, >> Vyacheslav Dubeyko. >> >> [1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a9bae189542e71f91e61a4428adf6e5a7dfe8063 >> >> > -- 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
