From: NeilBrown <neilb@suse.de>
Date: Wed, 7 Mar 2012 04:25:57 +0000 (+1100)
Subject: Manage: allow --re-add to failed array.
X-Git-Tag: mdadm-3.2.4~69
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c69ffac0d6a068823a1365c3b155ff72f8c4686f;p=thirdparty%2Fmdadm.git

Manage: allow --re-add to failed array.


If both "legs" of a RAID1 (or equivalent in RAID10) fail, then one
of the becomes available again it maybe appropriate to re-add the
failed device(s).
So remove the restriction that an array must has 'enough' devices
before being re-added, and if there is no-where to read a superblock
from for matching, then assume the kernel will do necessary checks.

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

diff --git a/Manage.c b/Manage.c
index d9775ded..4cf6e587 100644
--- a/Manage.c
+++ b/Manage.c
@@ -723,7 +723,13 @@ int Manage_subdevs(char *devname, int fd,
 					break;
 				}
 				/* FIXME this is a bad test to be using */
-				if (!tst->sb) {
+				if (!tst->sb &&
+				    dv->re_add) {
+					/* we are re-adding a device to a
+					 * completely dead array - have to depend
+					 * on kernel to check
+					 */
+				} else if (!tst->sb) {
 					close(tfd);
 					st->ss->free_super(st);
 					fprintf(stderr, Name ": cannot load array metadata from %s\n", devname);
@@ -747,12 +753,16 @@ int Manage_subdevs(char *devname, int fd,
 				 * and was temporarily removed, and is now being re-added.
 				 * If so, we can simply re-add it.
 				 */
-				tst->ss->uuid_from_super(tst, duuid);
 
 				if (st->sb) {
 					struct mdinfo mdi;
 					st->ss->getinfo_super(st, &mdi, NULL);
 					st->ss->uuid_from_super(st, ouuid);
+					if (tst->sb)
+						tst->ss->uuid_from_super(tst, duuid);
+					else
+						/* Assume uuid matches: kernel will check */
+						memcpy(duuid, ouuid, sizeof(ouuid));
 					if ((mdi.disk.state & (1<<MD_DISK_ACTIVE)) &&
 					    !(mdi.disk.state & (1<<MD_DISK_FAULTY)) &&
 					    memcmp(duuid, ouuid, sizeof(ouuid))==0) {
@@ -768,7 +778,7 @@ int Manage_subdevs(char *devname, int fd,
 						disc.number = mdi.disk.number;
 						if (ioctl(fd, GET_DISK_INFO, &disc) != 0
 						    || disc.major != 0 || disc.minor != 0
-						    || !enough_fd(fd))
+							)
 							goto skip_re_add;
 						disc.major = major(stb.st_rdev);
 						disc.minor = minor(stb.st_rdev);