-document.
-.PP
-When a directory with the `D' attribute set is modified,
-the changes are written synchronously on the disk; this is equivalent to
-the `dirsync' mount option applied to a subset of the files.
-.PP
-A file with the `d' attribute set is not candidate for backup when the
+document. (Note: For btrfs, If the 'c' flag is set, then the 'C' flag
+cannot be set. Also conflicts with btrfs mount option 'nodatasum')
+.TP
+.B C
+A file with the 'C' attribute set will not be subject to copy-on-write
+updates. This flag is only supported on file systems which perform
+copy-on-write. (Note: For btrfs, the 'C' flag should be
+set on new or empty files. If it is set on a file which already has
+data blocks, it is undefined when the blocks assigned to the file will
+be fully stable. If the 'C' flag is set on a directory, it will have no
+effect on the directory, but new files created in that directory will
+have the No_COW attribute set. If the 'C' flag is set, then the 'c' flag
+cannot be set.)
+.TP
+.B d
+A file with the 'd' attribute set is not a candidate for backup when the