Hi! > > In particular, using this functionality, user is able to push out > > "hot" files on any high-performance device (e.g. proxy device) and pin > > them there. What permissions are normally required for file migration? > > COMMENT. After ioctl successful completion the file is not necessarily > > written to the target device! To make sure of it, call fsync(2) after > > successful ioctl completion, or open the file with O_SYNC flag before > > migration. Ok. > > COMMENT. File migration is a volume operation (like adding, removing a device to/from > > a logical volumes), and all volume operations are serialized. So, any attempt to > > migrate a file, while performing other operation on that volume will fail. If some > > file migration procedure fails (with EBUSY, or other errors), or was interrupted by > > user, then it should be repeated in the current mount session. File migration > > procedures interrupted by system crash, hared reset, etc) should be repeated in the > > next mount sessions. Dunno. Returning -EBUSY is kind of "interesting" there. I'd expect kernel to queue the callers, because userland can't really do that easily. Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
