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
