On Thu, Sep 25, 2014 at 05:59:12PM +1000, Dave Chinner wrote: > > Also I'm afraid we may quickly run out of > > 32 available flags in xflags so we'd need to extend that. But all this > > seems to be doable. > > The struct fsxattr was designed to be extensible - it has unused > padding and enough space in the flags field to allow us to > conditionally use that padding.... I agree that it would be useful for ext4 to support as much of the XFS_IOC_GETXATTR/XFS_IOC_SETATTR as would make sense for ext4, and to use that to set/get the project ID. (And that we should probably do that as a separate set of patches that we could potentially go into ext4 ahead of the project quota while it is undergoing testing and review.) A few questions of Dave and other XFS folks: 1) If we only implement a partial set of the flags or other functionality, are there going to be tools that get confused? i.e., are there any userspace programs that will test for whether the ioctl is supported, and then assume that some minimal set of functionality must be implemented? 2) Unless I'm missing something, there is nothing that enforces that fsx_pad must be zero. I assume that means that the only way you can expand use of fields into that space is via a flag bit being consumed? Cheers, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
