On Tue, Jun 29, 2021 at 02:04:22PM -0700, Darrick J. Wong wrote: > > Why don't we deprecate FS_IOC_[GS]ETFLAGS and tell everyone to use > FS[GS]ETXATTR? They use the same code paths and vfs helpers now. The FS_IOC_[GS]ETXATTR ioctls use struct fsxattr, which contains fsx_xflags. But there are flags returned (and set) by FS_IOC_[GS]ETFLAGS that are not in fsx_xflags --- and vice versa, of course. That's not a problem for xfs, since fsx_xflags was originally designed for xfs (and so it has some xfs-specific flags such as FS_XFLAG_REALTIME, FS_XFLAG_RTINHERIT, FS_XFLAG_FILESTREAM, FS_XFLAG_COWEXTSIZE, etc.). But for other file systems, including btrfs, ext4 and f2fs, which utilize FS_IOC_[GS]ETFLAGS flags which are not supported by FS_IOC_[GS]ETXATTR's fsx_xflags. Examples of such flags include FS_ENCRYPT_FL, FS_TOPDIR_FL, FS_NOCMP_FL, and FS_CASEFOLD_FL. There is also the _IO[RW] long vs int "API violation" for the FS_IOC_[GS]ETVERSION which isn't addressed by FS_IOC_[GS]ETATTR. So FS_IOC_[GS]ETATTR isn't a complete replacement/solution for these "problem" ioctls. And of course, even if we were to start telling everyone to start using a new interface, it'll be many years before any transition is complete. - Ted
