Assemble - avoid including wayward devices.

If a device - typically in a mirrored set - is assembled independently
of the other devices, and then attempted to be brought back into the
set it could contain inconsistent data.  It should not be included.

So detect this situation by ensuring that the 'most recent' device is
believed to be active by every other device.  If a device is wayward,
it will only consider fellow wayward devices to be active and will
think all others are failed or missing.

This patch only fixes --assemble, not --incremental

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

1 files changed, 23 insertions, 2 deletions

diff --git a/Assemble.c b/Assemble.c
index d23c1307..f66a21b9 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -145,6 +145,7 @@ int Assemble(struct supertype *st, char *mddev,
 			       */
 		struct mdinfo i;
 	} *devices;
+	char *devmap;
 	int *best = NULL; /* indexed by raid_disk */
 	int bestcnt = 0;
 	int devcnt = 0;
@@ -603,6 +604,7 @@ int Assemble(struct supertype *st, char *mddev,
 	bitmap_done = 0;
 	content->update_private = NULL;
 	devices = malloc(num_devs * sizeof(*devices));
+	devmap = calloc(num_devs * content->array.raid_disks, 1);
 	for (tmpdev = devlist; tmpdev; tmpdev=tmpdev->next) if (tmpdev->used == 1) {
 		char *devname = tmpdev->devname;
 		struct stat stb;
@@ -640,9 +642,10 @@ int Assemble(struct supertype *st, char *mddev,
 					close(dfd);
 				close(mdfd);
 				free(devices);
+				free(devmap);
 				return 1;
 			}
-			tst->ss->getinfo_super(tst, content, NULL);
+			tst->ss->getinfo_super(tst, content, devmap + devcnt * content->array.raid_disks);
 
 			memcpy(content->uuid, ident->uuid, 16);
 			strcpy(content->name, ident->name);
@@ -665,6 +668,7 @@ int Assemble(struct supertype *st, char *mddev,
 				close(mdfd);
 				close(dfd);
 				free(devices);
+				free(devmap);
 				return 1;
 			}
 			if (strcmp(update, "uuid")==0 &&
@@ -703,9 +707,10 @@ int Assemble(struct supertype *st, char *mddev,
 					close(dfd);
 				close(mdfd);
 				free(devices);
+				free(devmap);
 				return 1;
 			}
-			tst->ss->getinfo_super(tst, content, NULL);
+			tst->ss->getinfo_super(tst, content, devmap + devcnt * content->array.raid_disks);
 			tst->ss->free_super(tst);
 			close(dfd);
 		}
@@ -776,6 +781,7 @@ int Assemble(struct supertype *st, char *mddev,
 					);
 				close(mdfd);
 				free(devices);
+				free(devmap);
 				return 1;
 			}
 			if (best[i] == -1
@@ -795,6 +801,7 @@ int Assemble(struct supertype *st, char *mddev,
 			st->ss->free_super(st);
 		close(mdfd);
 		free(devices);
+		free(devmap);
 		return 1;
 	}
 
@@ -828,6 +835,19 @@ int Assemble(struct supertype *st, char *mddev,
 					sparecnt++;
 				continue;
 			}
+		/* If this devices thinks that 'most_recent' has failed, then
+		 * we must reject this device.
+		 */
+		if (j != most_recent &&
+		    content->array.raid_disks > 0 &&
+		    devices[most_recent].i.disk.raid_disk >= 0 &&
+		    devmap[j * content->array.raid_disks + devices[most_recent].i.disk.raid_disk] == 0) {
+			if (verbose > -1)
+				fprintf(stderr, Name ": ignoring %s as it reports %s as failed\n",
+					devices[j].devname, devices[most_recent].devname);
+			best[i] = -1;
+			continue;
+		}
 		if (devices[j].i.events+event_margin >=
 		    devices[most_recent].i.events) {
 			devices[j].uptodate = 1;
@@ -841,6 +861,7 @@ int Assemble(struct supertype *st, char *mddev,
 				sparecnt++;
 		}
 	}
+	free(devmap);
 	while (force && !enough(content->array.level, content->array.raid_disks,
 				content->array.layout, 1,
 				avail, okcnt)) {