mdadm/0101-Super1-allow-RAID0-layout-setting-to-be-removed.patch
Neil Brown 5563a724f6 Accepting request 853269 from home:colyli:branches:Base:System
- There are some important fixes merged in mdadm upstream which
  should go with jsc#SLE-13700. This is the update from upstream
  mdadm including the important fixes we should have.
- Detail: show correct raid level when the array is inactive
  (jsc#SLE-13700)
  0095-Detail-show-correct-raid-level-when-the-array-is-ina.patch
- Don't create bitmap for raid5 with journal disk
  (jsc#SLE-13700)
  0096-Don-t-create-bitmap-for-raid5-with-journal-disk.patch
- Monitor: refresh mdstat fd after select (jsc#SLE-13700)
  0097-Monitor-refresh-mdstat-fd-after-select.patch
- Monitor: stop notifing about containers.  (jsc#SLE-13700)
  0098-Monitor-stop-notifing-about-containers.patch
- mdmonitor: set small delay once (jsc#SLE-13700)
  0099-mdmonitor-set-small-delay-once.patch
- Check if other Monitor instance running before fork.
  (jsc#SLE-13700)
  0100-Check-if-other-Monitor-instance-running-before-fork.patch
- Super1: allow RAID0 layout setting to be removed.
  (jsc#SLE-13700)
  0101-Super1-allow-RAID0-layout-setting-to-be-removed.patch
- Detail: fix segfault during IMSM raid creation
  (jsc#SLE-13700)
  0102-Detail-fix-segfault-during-IMSM-raid-creation.patch
- Create.c: close mdfd and generate uevent (jsc#SLE-13700)
  0103-Create.c-close-mdfd-and-generate-uevent.patch
- imsm: update num_data_stripes according to dev_size
  (jsc#SLE-13700)
  0104-imsm-update-num_data_stripes-according-to-dev_size.patch
- imsm: remove redundant calls to imsm_get_map (jsc#SLE-13700)

OBS-URL: https://build.opensuse.org/request/show/853269
OBS-URL: https://build.opensuse.org/package/show/Base:System/mdadm?expand=0&rev=191
2020-12-09 21:09:06 +00:00

137 lines
4.7 KiB
Diff

From 97b51a2c2d00b79a59f2a8e37134031b0c9e0223 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Wed, 14 Oct 2020 13:12:48 +1100
Subject: [PATCH 07/17] Super1: allow RAID0 layout setting to be removed.
Once the RAID0 layout has been set, the RAID0 array cannot be assembled
on an older kernel which doesn't understand layouts.
This is an intentional safety feature, but sometimes people need the
ability to roll-back to a previously working configuration.
So add "--update=layout-unspecified" to remove RAID0 layout information
from the superblock.
Running "--assemble --update=layout-unspecified" will cause the assembly
the fail when run on a newer kernel, but will allow it to work on
an older kernel.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
---
md.4 | 13 +++++++++++++
mdadm.8.in | 15 +++++++++++++--
mdadm.c | 5 +++--
super1.c | 6 +++++-
4 files changed, 34 insertions(+), 5 deletions(-)
diff --git a/md.4 b/md.4
index aecff38..60fdd27 100644
--- a/md.4
+++ b/md.4
@@ -215,6 +215,19 @@ option or the
.B "--update=layout-alternate"
option.
+Once you have updated the layout you will not be able to mount the array
+on an older kernel. If you need to revert to an older kernel, the
+layout information can be erased with the
+.B "--update=layout-unspecificed"
+option. If you use this option to
+.B --assemble
+while running a newer kernel, the array will NOT assemble, but the
+metadata will be update so that it can be assembled on an older kernel.
+
+No that setting the layout to "unspecified" removes protections against
+this bug, and you must be sure that the kernel you use matches the
+layout of the array.
+
.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 ab832e8..34a93a8 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -1213,6 +1213,7 @@ argument given to this flag can be one of
.BR no\-ppl ,
.BR layout\-original ,
.BR layout\-alternate ,
+.BR layout\-unspecified ,
.BR metadata ,
or
.BR super\-minor .
@@ -1368,8 +1369,9 @@ 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,
+options are for RAID0 arrays with non-uniform devices size that were 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
@@ -1379,6 +1381,15 @@ will happen normally.
For more information, see
.IR md (4).
+The
+.B layout\-unspecified
+option reverts the effect of
+.B layout\-orignal
+or
+.B layout\-alternate
+and allows the array to be again used on a kernel prior to Linux 5.3.
+This option should be used with great caution.
+
.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 1b3467f..493d70e 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -796,7 +796,8 @@ int main(int argc, char *argv[])
if (strcmp(c.update, "revert-reshape") == 0)
continue;
if (strcmp(c.update, "layout-original") == 0 ||
- strcmp(c.update, "layout-alternate") == 0)
+ strcmp(c.update, "layout-alternate") == 0 ||
+ strcmp(c.update, "layout-unspecified") == 0)
continue;
if (strcmp(c.update, "byteorder") == 0) {
if (ss) {
@@ -828,7 +829,7 @@ 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"
+ " 'layout-original', 'layout-alternate', 'layout-unspecified'\n"
);
exit(outf == stdout ? 0 : 2);
diff --git a/super1.c b/super1.c
index 7664883..8b0d6ff 100644
--- a/super1.c
+++ b/super1.c
@@ -1551,11 +1551,15 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
else if (strcmp(update, "nofailfast") == 0)
sb->devflags &= ~FailFast1;
else if (strcmp(update, "layout-original") == 0 ||
- strcmp(update, "layout-alternate") == 0) {
+ strcmp(update, "layout-alternate") == 0 ||
+ strcmp(update, "layout-unspecified") == 0) {
if (__le32_to_cpu(sb->level) != 0) {
pr_err("%s: %s only supported for RAID0\n",
devname?:"", update);
rv = -1;
+ } else if (strcmp(update, "layout-unspecified") == 0) {
+ sb->feature_map &= ~__cpu_to_le32(MD_FEATURE_RAID0_LAYOUT);
+ sb->layout = 0;
} else {
sb->feature_map |= __cpu_to_le32(MD_FEATURE_RAID0_LAYOUT);
sb->layout = __cpu_to_le32(update[7] == 'o' ? 1 : 2);
--
2.26.2