On Thu, Nov 13, 2014 at 08:02:43AM -0500, Trond Myklebust wrote: > On Wed, Nov 12, 2014 at 7:28 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: > > On Wed, Nov 12, 2014 at 09:26:16AM -0500, Trond Myklebust wrote: > >> On Wed, Nov 12, 2014 at 5:24 AM, Christoph Hellwig <hch@xxxxxx> wrote: > >> > On Wed, Nov 12, 2014 at 09:27:10AM +1100, Dave Chinner wrote: > >> >> To clarify what Christoph wrote, XFS updates i_version is updated > >> >> once per transaction that modifies the inode. So if a VFS level > >> >> operation results in multiple transactions then each transaction > >> >> will but the version. > >> >> > >> >> It was implemented that way because nobody could tell me what the > >> >> actual granularity requirement for change detection was. Hence what > >> >> I implemented was "be able to detect any persistent change that is > >> >> made" to cover all bases. FWIW, ext4 takes the same approach. See Ted's post today: http://www.spinics.net/lists/linux-ext4/msg46194.html "The inode_inc_iversion() in mark4_ext4_iloc_dirty() is probably not necessary, since we already should be incrementing i_version whenever ctime and mtime gets updated. The inode_inc_iversion() there is more of a "belt and suspenders" safety thing, on the theory that the extra bump in i_version won't hurt anything." Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
