xfs: don't mix reflink and DAX mode for now

Since we don't have a strategy for handling both DAX and reflink,
for now we'll just prohibit both being set at the same time.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_inode_buf.c

@@ -407,6 +407,10 @@ xfs_dinode_verify(
 	if ((flags2 & XFS_DIFLAG2_REFLINK) && (flags & XFS_DIFLAG_REALTIME))
 		return false;
 
+	/* don't let reflink and dax mix */
+	if ((flags2 & XFS_DIFLAG2_REFLINK) && (flags2 & XFS_DIFLAG2_DAX))
+		return false;
+
 	return true;
 }
 

fs/xfs/xfs_file.c

@@ -1055,6 +1055,10 @@ xfs_file_share_range(
 	if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
 		return -EINVAL;
 
+	/* Don't share DAX file data for now. */
+	if (IS_DAX(inode_in) || IS_DAX(inode_out))
+		return -EINVAL;
+
 	/* Are we going all the way to the end? */
 	isize = i_size_read(inode_in);
 	if (isize == 0)

fs/xfs/xfs_ioctl.c

@@ -1038,6 +1038,10 @@ xfs_ioctl_setattr_xflags(
 	if ((fa->fsx_xflags & FS_XFLAG_REALTIME) && xfs_is_reflink_inode(ip))
 		return -EINVAL;
 
+	/* Don't allow us to set DAX mode for a reflinked file for now. */
+	if ((fa->fsx_xflags & FS_XFLAG_DAX) && xfs_is_reflink_inode(ip))
+		return -EINVAL;
+
 	/*
 	 * Can't modify an immutable/append-only file unless
 	 * we have appropriate permission.

fs/xfs/xfs_iops.c

@@ -1144,6 +1144,7 @@ xfs_diflags_to_iflags(
 		inode->i_flags |= S_NOATIME;
 	if (S_ISREG(inode->i_mode) &&
 	    ip->i_mount->m_sb.sb_blocksize == PAGE_SIZE &&
+	    !xfs_is_reflink_inode(ip) &&
 	    (ip->i_mount->m_flags & XFS_MOUNT_DAX ||
 	     ip->i_d.di_flags2 & XFS_DIFLAG2_DAX))
 		inode->i_flags |= S_DAX;