From 63902857b98c37c8ac4b837bb01d006b327a4532 Mon Sep 17 00:00:00 2001

From: Heming Zhao <heming.zhao@suse.com>

Date: Tue, 21 Jun 2022 00:10:40 +0800

Subject: [PATCH 22/83] mdadm/super1: restore commit 45a87c2f31335 to fix

 clustered slot issue

Commit 9d67f6496c71 ("mdadm:check the nodes when operate clustered

array") modified assignment logic for st->nodes in write_bitmap1(),

which introduced bitmap slot issue:

load_super1 didn't set up supertype.nodes, which made spare disk only

have one slot info. Then it triggered kernel md_bitmap_load_sb to get

wrong bitmap slot data.

For fixing this issue, there are two methods:

1> revert the related code of commit 9d67f6496c71. and restore the code

   from former commit 45a87c2f31335 ("super1: add more checks for

   NodeNumUpdate option").

   st->nodes value would be 0 & 1 under current code logic. i.e.

   When adding a spare disk, there is no place to init st->nodes, and

   the value is ZERO.

2> keep 9d67f6496c71, add additional ->nodes handling in load_super1(),

   let load_super1 to set st->nodes when bitmap is BITMAP_MAJOR_CLUSTERED.

   Under current mdadm code logic, load_super1 will be called many

   times, any new code in load_super1 will cost mdadm running more time.

   And more reason is I prefer as much as possible to limit clustered

   code spreading in every corner.

So I used method <1> to fix this issue.

How to trigger:

dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sda

dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sdb

dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sdc

mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda /dev/sdb

mdadm -a /dev/md0 /dev/sdc

mdadm /dev/md0 --fail /dev/sda

mdadm /dev/md0 --remove /dev/sda

mdadm -Ss

mdadm -A /dev/md0 /dev/sdb /dev/sdc

the output of current "mdadm -X /dev/sdc":

(there should be (by default) 4 slot info for correct output)

```

        Filename : /dev/sdc

           Magic : 6d746962

         Version : 5

            UUID : a74642f8:a6b1fba8:58e1f8db:cfe7b082

          Events : 29

  Events Cleared : 0

           State : OK

       Chunksize : 64 MB

          Daemon : 5s flush period

      Write Mode : Normal

       Sync Size : 306176 (299.00 MiB 313.52 MB)

          Bitmap : 5 bits (chunks), 5 dirty (100.0%)

```

And mdadm later operations will trigger kernel output error message:

(triggered by "mdadm -A /dev/md0 /dev/sdb /dev/sdc")

```

kernel: md0: invalid bitmap file superblock: bad magic

kernel: md_bitmap_copy_from_slot can't get bitmap from slot 1

kernel: md-cluster: Could not gather bitmaps from slot 1

kernel: md0: invalid bitmap file superblock: bad magic

kernel: md_bitmap_copy_from_slot can't get bitmap from slot 2

kernel: md-cluster: Could not gather bitmaps from slot 2

kernel: md0: invalid bitmap file superblock: bad magic

kernel: md_bitmap_copy_from_slot can't get bitmap from slot 3

kernel: md-cluster: Could not gather bitmaps from slot 3

kernel: md-cluster: failed to gather all resyn infos

kernel: md0: detected capacity change from 0 to 612352

```

Acked-by: Coly Li <colyli@suse.de>

Signed-off-by: Heming Zhao <heming.zhao@suse.com>

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

---

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

 1 file changed, 11 insertions(+), 1 deletion(-)

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

index e3e2f954..3a0c69fd 100644

--- a/super1.c

+++ b/super1.c

@@ -2674,7 +2674,17 @@ static int write_bitmap1(struct supertype *st, int fd, enum bitmap_update update

 		}

 		if (bms->version == BITMAP_MAJOR_CLUSTERED) {

-			if (__cpu_to_le32(st->nodes) < bms->nodes) {

+			if (st->nodes == 1) {

+				/* the parameter for nodes is not valid */

+				pr_err("Warning: cluster-md at least needs two nodes\n");

+				return -EINVAL;

+			} else if (st->nodes == 0) {

+				/*

+				 * parameter "--nodes" is not specified, (eg, add a disk to

+				 * clustered raid)

+				 */

+				break;

+			} else if (__cpu_to_le32(st->nodes) < bms->nodes) {

 				/*

 				 * Since the nodes num is not increased, no

 				 * need to check the space enough or not,

-- 

2.38.1