On Mon, Mar 16, 2015 at 10:33:45PM +0000, Al Viro wrote: > On Mon, Mar 16, 2015 at 03:43:20PM +1100, NeilBrown wrote: > > When we support ->follow_link in RCU-walk we will not want to > > take a reference to the 'struct path *link' passed to follow_link, > > and correspondingly will not want to drop that reference. > > > > As link_path_walk will complete_walk() in the case of an error, > > and as complete_walk() will clear LOOKUP_RCU, we cannot test > > LOOKUP_RCU to determine if the path should be 'put'. > > > > So introduce a new flag: LOOKUP_LINK_RCU. This is set on > > entry to follow_link() if appropriate and put_link() will > > only call path_put() if it is clear. > > Umm... How is it different from nd->depth > 0 && nd->flags & LOOKUP_RCU? > IOW, could we bump nd->depth before that (conditional) mntget()?
OK, I see... So you are holding that flag for as long as we are traversing any part of a symlink body, including that of a trailing symlink... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
