On Fri, Sep 04, 2020 at 09:14:25AM +0800, Xiao Yang wrote: > On 2020/9/3 15:46, Dave Chinner wrote: > > On Thu, Sep 03, 2020 at 11:57:13AM +0800, Xiao Yang wrote: > > > Current ioctl(FSSETXATTR) ignores unsupported xflags silently > > > so it is not clear for user to know unsupported xflags. > > > For example, use ioctl(FSSETXATTR) to set dax flag on kernel > > > v4.4 which doesn't support dax flag: > > > -------------------------------- > > > # xfs_io -f -c "chattr +x" testfile;echo $? > > > 0 > > > # xfs_io -c "lsattr" testfile > > > ----------------X testfile > > > -------------------------------- > > > > > > Add check to return -EOPNOTSUPP as ext4/f2fs/btrfs does. > > > > > > Signed-off-by: Xiao Yang<yangx.jy@xxxxxxxxxxxxxx> > > > Reviewed-by: Darrick J. Wong<darrick.wong@xxxxxxxxxx> > > > --- > > > fs/xfs/xfs_ioctl.c | 12 ++++++++++++ > > > 1 file changed, 12 insertions(+) > > > > > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > > > index 6f22a66777cd..59f9a86f29f7 100644 > > > --- a/fs/xfs/xfs_ioctl.c > > > +++ b/fs/xfs/xfs_ioctl.c > > > @@ -1425,6 +1425,14 @@ xfs_ioctl_setattr_check_projid( > > > return 0; > > > } > > > > > > +#define XFS_SUPPORTED_FS_XFLAGS \ > > > + (FS_XFLAG_REALTIME | FS_XFLAG_PREALLOC | FS_XFLAG_IMMUTABLE | \ > > > + FS_XFLAG_APPEND | FS_XFLAG_SYNC | FS_XFLAG_NOATIME | FS_XFLAG_NODUMP | \ > > > + FS_XFLAG_RTINHERIT | FS_XFLAG_PROJINHERIT | FS_XFLAG_NOSYMLINKS | \ > > > + FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT | FS_XFLAG_NODEFRAG | \ > > > + FS_XFLAG_FILESTREAM | FS_XFLAG_DAX | FS_XFLAG_COWEXTSIZE | \ > > > + FS_XFLAG_HASATTR) > > > + > > > STATIC int > > > xfs_ioctl_setattr( > > > xfs_inode_t *ip, > > > @@ -1439,6 +1447,10 @@ xfs_ioctl_setattr( > > > > > > trace_xfs_ioctl_setattr(ip); > > > > > > + /* Check if fsx_xflags has unsupported xflags */ > > > + if (fa->fsx_xflags& ~XFS_SUPPORTED_FS_XFLAGS) > > > + return -EOPNOTSUPP; > > I don't think we can do this as it may break existing applications > > that have been working on XFS for many, many years that don't > > correctly initialise fsx_xflags.... > Hi Dave, > > It seems that the only way is to keep the current behavior. :-( Yes, unfortunately that is the case, but it does follow precedence set by other syscalls with unchecked flags such as open() - they mask off unknown flags so they don't do anything, but they do not return an error if any unknown flag is set. > By the way, _require_xfs_io_command "chattr" in xfstests cannot check XFS's > unsupported xflags directly because of the behavior, so we may need to check > them by extra xfs_io -c "lsattr". *nod* Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
