On Thu, Aug 04, 2016 at 04:02:46PM -0400, Eric Whitney wrote: > The existing _require_defrag function rejects ext4 file systems > mounted with the dax option or constructed without extents. However, > there are also a number of other ext4 file system configuration cases > that do not currently support online defrag, including encryption, data > journaling, and bigalloc. In the future, online defrag functionality > may be implemented for some of these, and new configuration cases > could be added that don't support it. > > Rather than add a laundry list of mount and file system configuration > options to the existing _require_defrag function that will need ongoing > maintenance, use the available src/e4compact program to directly > determine whether the kernel supports ext4's move extent ioctl on the > test file system. This look reasonable - but I wonder if we could just come up with an even more generic version that uses your approach on all file systems, so that the only per-fs logic left would be to apply the DEFRAG_PROG variable. -- 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