[PATCH V2] xfs_io: add RWF_DSYNC support to pwrite

[Dave Chinner <david@fromorbit.com>]

From: Dave Chinner <dchinner@redhat.com>

Enable testing write behaviour with the per-io RWF_DSYNC flag.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
---

V2: updated shortform help string and added command to the man page.

 io/pwrite.c       |  8 ++++++--
 man/man8/xfs_io.8 | 10 ++++++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/io/pwrite.c b/io/pwrite.c
index a89edfd0496f..74cc5882fe4b 100644
--- a/io/pwrite.c
+++ b/io/pwrite.c
@@ -56,6 +56,7 @@ pwrite_help(void)
 #endif
 #ifdef HAVE_PWRITEV2
 " -N   -- Perform the pwritev2() with RWF_NOWAIT\n"
+" -D   -- Perform the pwritev2() with RWF_DSYNC\n"
 #endif
 "\n"));
 }
@@ -299,7 +300,7 @@ pwrite_f(
 	init_cvtnum(&fsblocksize, &fssectsize);
 	bsize = fsblocksize;
 
-	while ((c = getopt(argc, argv, "b:BCdf:Fi:NqRs:OS:uV:wWZ:")) != EOF) {
+	while ((c = getopt(argc, argv, "b:BCdDf:Fi:NqRs:OS:uV:wWZ:")) != EOF) {
 		switch (c) {
 		case 'b':
 			tmp = cvtnum(fsblocksize, fssectsize, optarg);
@@ -335,6 +336,9 @@ pwrite_f(
 		case 'N':
 			pwritev2_flags |= RWF_NOWAIT;
 			break;
+		case 'D':
+			pwritev2_flags |= RWF_DSYNC;
+			break;
 #endif
 		case 's':
 			skip = cvtnum(fsblocksize, fssectsize, optarg);
@@ -469,7 +473,7 @@ pwrite_init(void)
 	pwrite_cmd.argmax = -1;
 	pwrite_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
 	pwrite_cmd.args =
-_("[-i infile [-dwNOW] [-s skip]] [-b bs] [-S seed] [-FBR [-Z N]] [-V N] off len");
+_("[-i infile [-dDwNOW] [-s skip]] [-b bs] [-S seed] [-FBR [-Z N]] [-V N] off len");
 	pwrite_cmd.oneline =
 		_("writes a number of bytes at a specified offset");
 	pwrite_cmd.help = pwrite_help;
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 8bf3f57bd30e..ad9cf390b3c9 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -222,7 +222,7 @@ See the
 .B pread
 command.
 .TP
-.BI "pwrite [ \-i " file " ] [ \-dwNOW ] [ \-s " skip " ] [ \-b " size " ] [ \-S " seed " ] [ \-FBR [ \-Z " zeed " ] ] [ \-V " vectors " ] " "offset length"
+.BI "pwrite [ \-i " file " ] [ \-dDwNOW ] [ \-s " skip " ] [ \-b " size " ] [ \-S " seed " ] [ \-FBR [ \-Z " zeed " ] ] [ \-V " vectors " ] " "offset length"
 Writes a range of bytes in a specified blocksize from the given
 .IR offset .
 The bytes written can be either a set pattern or read in from another
@@ -248,7 +248,13 @@ once all writes are complete (included in timing results)
 Perform the
 .BR pwritev2 (2)
 call with
-.I RWF_NOWAIT.
+.IR RWF_NOWAIT .
+.TP
+.B \-D
+Perform the
+.BR pwritev2 (2)
+call with
+.IR RWF_DSYNC .
 .TP
 .B \-O
 perform pwrite once and return the (maybe partial) bytes written.