Make CCD be able to read and write Linux software raids.

Supported for raid-0 with <n> disks, raid-1 with 2 disks.

Manpages have examples, warnings etc.

Test scripts on
http://www.cons.org/cracauer/ccdconfig-linux/
Reviewed by:	alfred

2 files changed, 26 insertions, 0 deletions

diff --git a/sbin/ccdconfig/ccdconfig.8 b/sbin/ccdconfig/ccdconfig.8
index 4ba08be..bbd7428 100644
--- a/sbin/ccdconfig/ccdconfig.8
+++ b/sbin/ccdconfig/ccdconfig.8
@@ -104,6 +104,8 @@ The flags are as follows:
 .Bd -literal -offset indent
 CCDF_UNIFORM	0x02		Use uniform interleave
 CCDF_MIRROR	0x04		Support mirroring
+CCDF_NO_OFFSET	0x08		Do not use an offset
+CCDF_LINUX	0x0A		Linux md(4) compatibility
 .Ed
 .Pp
 The format in the
@@ -127,6 +129,10 @@ The component devices need to name partitions of type
 .Dq 4.2BSD
 as shown by
 .Xr disklabel 8 ) .
+.Pp
+If you want to use the Linux md(4) compatibility mode, please be sure
+to read the notes in
+.Xr ccd 4 .
 .Sh FILES
 .Bl -tag -width /etc/ccd.conf -compact
 .It Pa /etc/ccd.conf
@@ -159,6 +165,16 @@ and assigned to ccd0.
 # ccdconfig ccd0 128 CCDF_MIRROR /dev/da8s2 /dev/da9s3
 .Ed
 .Pp
+The following are matching commands in Linux and FreeBSD to create a
+raid-0 in Linux and read it from FreeBSD.
+.Bd -literal
+# Create a raid-0 on Linux:
+mdadm --create --chunk=32 --level=0 --raid-devices=2 /dev/md0 \\
+   /dev/hda1 /dev/hdb1
+# Make the raid-0 just created available on FreeBSD:
+ccdconfig -c /dev/ccd0 32 linux /dev/ad0s1 /dev/ad0s2
+.Ed
+.Pp
 When you create a new ccd disk you generally want to
 .Xr fdisk 8
 and
diff --git a/sbin/ccdconfig/ccdconfig.c b/sbin/ccdconfig/ccdconfig.c
index 0c584ff..928aba5 100644
--- a/sbin/ccdconfig/ccdconfig.c
+++ b/sbin/ccdconfig/ccdconfig.c
@@ -50,6 +50,8 @@ __FBSDID("$FreeBSD$");
 
 #define CCDF_UNIFORM    0x02    /* use LCCD of sizes for uniform interleave */
 #define CCDF_MIRROR     0x04    /* use mirroring */
+#define CCDF_NO_OFFSET  0x08    /* do not leave space in front */
+#define CCDF_LINUX      0x10    /* use Linux compatibility mode */
 
 #include "pathnames.h"
 
@@ -65,6 +67,10 @@ struct	flagval {
 	{ "uniform",		CCDF_UNIFORM },
 	{ "CCDF_MIRROR",	CCDF_MIRROR },
 	{ "mirror",		CCDF_MIRROR },
+	{ "CCDF_NO_OFFSET",	CCDF_NO_OFFSET },
+	{ "no_offset",		CCDF_NO_OFFSET },
+	{ "CCDF_LINUX",		CCDF_LINUX },
+	{ "linux",		CCDF_LINUX },
 	{ "none",		0 },
 	{ NULL,			0 },
 };
@@ -245,6 +251,10 @@ do_single(int argc, char **argv, int action)
 		gctl_ro_param(grq, "uniform", -1, "");
 	if (flags & CCDF_MIRROR)
 		gctl_ro_param(grq, "mirror", -1, "");
+	if (flags & CCDF_NO_OFFSET)
+		gctl_ro_param(grq, "no_offset", -1, "");
+	if (flags & CCDF_LINUX)
+		gctl_ro_param(grq, "linux", -1, "");
 	gctl_ro_param(grq, "nprovider", sizeof(argc), &argc);
 	for (i = 0; i < argc; i++) {
 		sprintf(buf1, "provider%d", i);