From 75a410f6226d1e3ef441bbb8cd4f198d5de5cf5b Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Wed, 31 Oct 2012 17:02:42 +1100
Subject: [PATCH] Incremental: allow recently removed device to be added as a
 spare.

Currently, action=force-spare isn't effective at all as I'm not
sure what is really sensible.
This patch allows a device that was part of an array, but has been
removed, to be added as a spare of passed to --incremental while
force-spare is active.

If it is can be re-added, that done first.  If it fails, we add it as
a spare.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 Incremental.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/Incremental.c b/Incremental.c
index bc23a88..19e4a1e 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -317,7 +317,7 @@ int Incremental(char *devname, struct context *c,
 		dinfo.disk.major = major(stb.st_rdev);
 		dinfo.disk.minor = minor(stb.st_rdev);
 		if (add_disk(mdfd, st, &info, &dinfo) != 0) {
-			pr_err("failed to add %s to %s: %s.\n",
+			pr_err("failed to add %s to new array %s: %s.\n",
 				devname, chosen_name, strerror(errno));
 			ioctl(mdfd, STOP_ARRAY, 0);
 			rv = 2;
@@ -433,8 +433,20 @@ int Incremental(char *devname, struct context *c,
 				    info.events, c->verbose, chosen_name);
 			err = add_disk(mdfd, st, sra, &info);
 		}
+		if (err < 0 && errno == EINVAL &&
+		    info.disk.state & (1<<MD_DISK_SYNC)) {
+			/* Maybe it needs to be added as a spare */
+			if (policy_action_allows(policy, st->ss->name,
+						 act_force_spare)) {
+				info.disk.state &= ~(1<<MD_DISK_SYNC);
+				err = add_disk(mdfd, st, sra, &info);
+			} else
+				if (c->verbose >= 0)
+					pr_err("can only add %s to %s as a spare, and force-spare is not set.\n",
+					       devname, chosen_name);
+		}
 		if (err < 0) {
-			pr_err("failed to add %s to %s: %s.\n",
+			pr_err("failed to add %s to existing array %s: %s.\n",
 				devname, chosen_name, strerror(errno));
 			rv = 2;
 			goto out_unlock;