i have read just recently and in the past that btrfs supports COW for _any_ file/directory (this is reflinks, yes?), and today i accidentally noticed that i can mount a directory as well (if it's in the top level volume at least). eg. if i have a "regular" directory (not a subvolume) in the top-level: /__boot i can mount it with: mount -o subvol=__boot /dev/sda /mnt is this supposed to be supported via the "subvol" mount option? though it sounds like i've answered my own question, i ask because playing around with this caused my kernel to oops for the first time in a long, long time (on .35 but just about to upgrade to .36 in about 10 min). i am working on an update to my initramfs hook that will utilize extlinux, and this property to provide seamless kernel level system rollbacks, and i want to make sure it's safe to do this. also, is there a way to target an arbitrary directory? does "subvol" support paths yet, or maybe via "subvolid" somehow? essentially i just want to mount a directory inside a snapshot at /boot, so when users upgrade there kernels, the images are visible to extlinux (which cannot yet peek inside or use subvolumes, so it has to be a regular directory in the top-level volume) any insight is much appreciated. C Anthony -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
