On Thu, Nov 13, 2014 at 03:14:33PM +0100, David Herrmann wrote: > Several pseudo file-systems create default mountpoints in /sys/fs/ or > /sys/kernel/, including: > /sys/kernel/debug > /sys/fs/mqueue > /sys/fs/cgroup > /sys/fs/pstore > > If the given pseudo file-system is available as a module, user-space can > rely on mount(2) to load the module on-demand (assuming MODULE_ALIAS_FS). > However, in case the default mount-point is created by the file-system > itself, mount(2) will fail as it cannot pin the mountpoint. > > This patch makes mount(2) load any requested file-systems before pinning > the target mount-point. This way, a file-system module can create default > mount-points in the module instead of creating them statically in the > core kernel.
I'm not taking that until I see a module that would attempt to do such mountpoint creation *and* managed to get it race-free. Besides, I really don't like the way you do this lookup only to never use the result other than for pinning the damn module. But that's secondary - the main issue is with the amount of fun races in the whole "let module create that default mountpoint" approach. -- 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/
