On Mon, Nov 26, 2012 at 11:53:45AM +0000, Alan Cox wrote: > > It's not like there is any shortage of flag bits, so what's the harm > > of reserving the bit? > > Why not just reserve a small group of bits for fs private use in that > case - for any fs. Flawed - one bit, one function for all filesystems, otherwise the same binary could behave very differently on different filesystems. Besides, we already have a mechanism for adding filesystem specific interfaces. It's called an ioctl. That's what it's there for - a free-form extensible interface that can be wholly defined and contained in the out-of-tree patch. Most filesystems implement ioctls for their own specific functionality, including for one-off preallocation semantics (e.g. XFS_IOC_ZERO_RANGE). There is no reason why ext4 can't do the same thing and we can drop the whole issue of having to modify a syscall API with magic, undocumented flag bits with unpredictable behaviour.... ext4 is not a special snowflake that allows developers to bend rules whenever they want. If the ext4 developers want to support out of tree functionality for their filesystem, then they can do it within their filesystem via ioctls like everyone else does. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
