On Mon, Jan 06, 2014 at 12:02:51AM +0100, Gerhard Heift wrote: > I am currently playing with snapshots and manual deduplication of > files. During these tests I noticed the change of ctime and mtime in > the snapshot after the deduplication with FILE_EXTENT_SAME. Does this > happens on purpose? Otherwise I would like to have ctime and mtime > left unmodified, because on a read only snapshot I cannot change them > back after the ioctl call. I'm not sure what's the correct behaviour wrt timestamps and extent cloning. The inode metadata are modified in some way, but the stat data and actual contents are left unchanged, so the timestamps do not reflect that something changed according to their definition (stat(2)). On the other hand, the differences can be seen in the extent listing, the physical offset of the blocks will change. I'm not aware of any tools that would become broken by breaking this assumption. Also, the (partial) cloning functionality is not implemented anywhere so we could have a look and try to stay consistent with that. My oppinion is to drop the mtime/iversion updates completely. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
