From: Alexander Klimov <a@kli.mov>
Subject: [patch] [ok?] bioctl: allow -c 1 with only one chunk for degraded arrays
To: tech@openbsd.org
Date: Fri, 26 Apr 2024 18:04:13 +0200



On 26.04.24 14:47, Stefan Sperling wrote:
> I agree that bioctl should allow attaching any volumes in degraded state
> at run-time, like it does for RAID 1C.  The min_disks check should of
> course still apply when a volume is initially created. But this check
> needs to be done in the kernel, as bioctl doesn't know the volume's state.

Indeed, just lowering a number in /sbin/bioctl wasn't it all for RAID 1.
The kernel still complained about too few chunks, so I had to enable such not just for 1C.
With the below proper handling in the RAID 1 code I actually got a degraded RAID 1
re-assembled at runtime and could re-build it then. (-R)

Ok?

--- /usr/src/sbin/bioctl/bioctl.c	Fri Apr 26 07:45:28 2024
+++ /usr/src/sbin/bioctl/bioctl.c	Fri Apr 26 09:50:47 2024
@@ -851,7 +851,7 @@
  		min_disks = 2;
  		break;
  	case 1:
-		min_disks = 2;
+		min_disks = 1;
  		break;
  	case 5:
  		min_disks = 3;
--- /usr/src/sys/dev/softraid.c	Fri Apr 26 08:48:23 2024
+++ /usr/src/sys/dev/softraid.c	Fri Apr 26 09:52:13 2024
@@ -3411,7 +3411,7 @@
  	} else {

  		/* Ensure we are assembling the correct # of chunks. */
-		if (bc->bc_level == 0x1C &&
+		if ((bc->bc_level == 1 || bc->bc_level == 0x1C) &&
  		    sd->sd_meta->ssdi.ssd_chunk_no > no_chunk) {
  			sr_warn(sc, "trying to bring up %s degraded",
  			    sd->sd_meta->ssd_devname);
--- /usr/src/sys/dev/softraid_raid1.c	Fri Apr 26 09:40:15 2024
+++ /usr/src/sys/dev/softraid_raid1.c	Fri Apr 26 09:47:48 2024
@@ -52,6 +52,8 @@
  void	sr_raid1_set_chunk_state(struct sr_discipline *, int, int);
  void	sr_raid1_set_vol_state(struct sr_discipline *);

+extern int sr_raid1c_add_offline_chunks(struct sr_discipline *, int);
+
  /* Discipline initialisation. */
  void
  sr_raid1_discipline_init(struct sr_discipline *sd)
@@ -91,6 +93,15 @@
  sr_raid1_assemble(struct sr_discipline *sd, struct bioc_createraid *bc,
      int no_chunk, void *data)
  {
+	int rv;
+
+	/* Create NODEV place-holders for missing chunks. */
+	if (no_chunk < sd->sd_meta->ssdi.ssd_chunk_no) {
+		rv = sr_raid1c_add_offline_chunks(sd, no_chunk);
+		if (rv)
+			return (rv);
+	}
+
  	return sr_raid1_init(sd);
  }