man: document the DAX fsxattr inode flag

Document the new inode flag in struct fsxattr for DAX.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/man/man3/xfsctl.3 b/man/man3/xfsctl.3
index e84b829d277ecf0b4fbbbb23d805839e0feb5696..9e7f1382682aaad63f9099ec9c0329ded0eba7dd 100644 (file)
--- a/man/man3/xfsctl.3
+++ b/man/man3/xfsctl.3
@@ -225,6 +225,11 @@ group and so files within different directories will not interleave
 extents on disk. The reservation is only active while files are being
 created and written into the directory.
 .TP
+.SM "Bit 15 (0x8000) \- XFS_XFLAG_DAX"
+If the filesystem lives on directly accessible persistent memory, reads and
+writes to this file will go straight to the persistent memory, bypassing the
+page cache.
+.TP
 .SM "Bit 31 (0x80000000) \- XFS_XFLAG_HASATTR"
 The file has extended attributes associated with it.
 .RE