From 027c099fd1a31fb3815e592de75d0791a22353b4 Mon Sep 17 00:00:00 2001

From: NeilBrown <neilb@suse.de>

Date: Mon, 4 Nov 2019 14:27:49 +1100

Subject: [RHEL8.2 PATCH 55/61] Assemble: add support for RAID0 layouts.

If you have a RAID0 array with varying sized devices

on a kernel before 5.4, you cannot assembling it on

5.4 or later without explicitly setting the layout.

This is now possible with

  --update=layout-original (For 3.13 and earlier kernels)

or

  --update=layout-alternate (for 3.14 and later kernels)

Signed-off-by: NeilBrown <neilb@suse.de>

Signed-off-by: Jes Sorensen <jsorensen@fb.com>

---

 Assemble.c |  8 ++++++++

 md.4       |  7 +++++++

 mdadm.8.in | 17 +++++++++++++++++

 mdadm.c    |  4 ++++

 super1.c   | 12 +++++++++++-

 5 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/Assemble.c b/Assemble.c

index b2e6914..6b5a7c8 100644

--- a/Assemble.c

+++ b/Assemble.c

@@ -1031,6 +1031,11 @@ static int start_array(int mdfd,

 				pr_err("failed to add %s to %s: %s\n",

 				       devices[j].devname, mddev,

 				       strerror(errno));

+				if (errno == EINVAL && content->array.level == 0 &&

+				    content->array.layout != 0) {

+					cont_err("Possibly your kernel doesn't support RAID0 layouts.\n");

+					cont_err("Please upgrade.\n");

+				}

 				if (i < content->array.raid_disks * 2 ||

 				    i == bestcnt)

 					okcnt--;

@@ -1220,6 +1225,9 @@ static int start_array(int mdfd,

 			return 0;

 		}

 		pr_err("failed to RUN_ARRAY %s: %s\n", mddev, strerror(errno));

+		if (errno == 524 /* ENOTSUP */ &&

+		    content->array.level == 0 && content->array.layout == 0)

+			cont_err("Please use --update=layout-original or --update=layout-alternate\n");

 		if (!enough(content->array.level, content->array.raid_disks,

 			    content->array.layout, 1, avail))

diff --git a/md.4 b/md.4

index 6fe2755..0712af2 100644

--- a/md.4

+++ b/md.4

@@ -208,6 +208,13 @@ array,

 will record the chosen layout in the metadata in a way that allows newer

 kernels to assemble the array without needing a module parameter.

+To assemble an old array on a new kernel without using the module parameter,

+use either the

+.B "--update=layout-original"

+option or the

+.B "--update=layout-alternate"

+option.

+

 .SS RAID1

 A RAID1 array is also known as a mirrored set (though mirrors tend to

diff --git a/mdadm.8.in b/mdadm.8.in

index fc9b6a6..6b63bb4 100644

--- a/mdadm.8.in

+++ b/mdadm.8.in

@@ -1213,6 +1213,8 @@ argument given to this flag can be one of

 .BR no\-bbl ,

 .BR ppl ,

 .BR no\-ppl ,

+.BR layout\-original ,

+.BR layout\-alternate ,

 .BR metadata ,

 or

 .BR super\-minor .

@@ -1364,6 +1366,21 @@ The

 .B no\-ppl

 option will disable PPL in the superblock.

+The

+.B layout\-original

+and

+.B layout\-alternate

+options are for RAID0 arrays in use before Linux 5.4.  If the array was being

+used with Linux 3.13 or earlier, then to assemble the array on a new kernel,

+.B \-\-update=layout\-original

+must be given.  If the array was created and used with a kernel from Linux 3.14 to

+Linux 5.3, then

+.B \-\-update=layout\-alternate

+must be given.  This only needs to be given once.  Subsequent assembly of the array

+will happen normally.

+For more information, see

+.IR md (4).

+

 .TP

 .BR \-\-freeze\-reshape

 Option is intended to be used in start-up scripts during initrd boot phase.

diff --git a/mdadm.c b/mdadm.c

index e438f9c..256a97e 100644

--- a/mdadm.c

+++ b/mdadm.c

@@ -795,6 +795,9 @@ int main(int argc, char *argv[])

 				continue;

 			if (strcmp(c.update, "revert-reshape") == 0)

 				continue;

+			if (strcmp(c.update, "layout-original") == 0 ||

+			    strcmp(c.update, "layout-alternate") == 0)

+				continue;

 			if (strcmp(c.update, "byteorder") == 0) {

 				if (ss) {

 					pr_err("must not set metadata type with --update=byteorder.\n");

@@ -825,6 +828,7 @@ int main(int argc, char *argv[])

 		"     'summaries', 'homehost', 'home-cluster', 'byteorder', 'devicesize',\n"

 		"     'no-bitmap', 'metadata', 'revert-reshape'\n"

 		"     'bbl', 'no-bbl', 'force-no-bbl', 'ppl', 'no-ppl'\n"

+		"     'layout-original', 'layout-alternate'\n"

 				);

 			exit(outf == stdout ? 0 : 2);

diff --git a/super1.c b/super1.c

index cedbb53..e0d80be 100644

--- a/super1.c

+++ b/super1.c

@@ -1550,7 +1550,17 @@ static int update_super1(struct supertype *st, struct mdinfo *info,

 		sb->devflags |= FailFast1;

 	else if (strcmp(update, "nofailfast") == 0)

 		sb->devflags &= ~FailFast1;

-	else

+	else if (strcmp(update, "layout-original") == 0 ||

+		 strcmp(update, "layout-alternate") == 0) {

+		if (__le32_to_cpu(sb->level) != 0) {

+			pr_err("%s: %s only supported for RAID0\n",

+			       devname?:"", update);

+			rv = -1;

+		} else {

+			sb->feature_map |= __cpu_to_le32(MD_FEATURE_RAID0_LAYOUT);

+			sb->layout = __cpu_to_le32(update[7] == 'o' ? 1 : 2);

+		}

+	} else

 		rv = -1;

 	sb->sb_csum = calc_sb_1_csum(sb);

-- 

2.7.5