Miklos Szeredi: > On Thu, Mar 14, 2013 at 12:19 AM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: ::: > > As for whiteouts... I think we ought to pull these bits of unionmoun > > queue into the common stem and add the missing filesystems to them; > > ext* and ufs are trivial (keep in mind that FFS derivatives, including > > ext*, have d_type in directory entry and type 14 (DT_WHT) is there > > precisely for that purpose). btrfs also has "dir_type" thing - 8bit > > field... > > What about userspace interfaces? Are we allowed to extend d_type and > st_mode without breaking things? Introducing a new d_type value can be a headache for other filesystems or other OSs. Whiteout and opaque by xattr is an idea, but I prefer more primitive way (special hidden filename) since xattr may force users to change their configuration and it consumes disk space a little. Filesystems may have a limit for the consumed size by xattr. If xattr reaches the limit, then several operation in overlayfs will be unusable. J. R. Okajima -- 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
