Add new mode: --incremental

--incremental allows arrays to be assembled one device at a time.
This is expected to be used with udev.

1 files changed, 721 insertions, 0 deletions

diff --git a/Incremental.c b/Incremental.c
new file mode 100644
index 0000000..ebe501f
--- /dev/null
+++ b/Incremental.c
@@ -0,0 +1,721 @@
+/*
+ * Incremental.c - support --incremental.  Part of:
+ * mdadm - manage Linux "md" devices aka RAID arrays.
+ *
+ * Copyright (C) 2006 Neil Brown <neilb@suse.de>
+ *
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *    Author: Neil Brown
+ *    Email: <neilb@suse.de>
+ *    Paper: Neil Brown
+ *           Novell Inc
+ *           GPO Box Q1283
+ *           QVB Post Office, NSW 1230
+ *           Australia
+ */
+
+#include	"mdadm.h"
+
+static int count_active(struct supertype *st, int mdfd, char **availp,
+			struct mdinfo *info);
+static void find_reject(int mdfd, struct supertype *st, struct sysarray *sra,
+			int number, __u64 events, int verbose,
+			char *array_name);
+
+int Incremental(char *devname, int verbose, int runstop,
+		struct supertype *st, char *homehost, int autof)
+{
+	/* Add this device to an array, creating the array if necessary
+	 * and starting the array if sensibe or - if runstop>0 - if possible.
+	 *
+	 * This has several steps:
+	 *
+	 * 1/ Check if device is permitted by mdadm.conf, reject if not.
+	 * 2/ Find metadata, reject if none appropriate (check
+	 *       version/name from args)
+	 * 3/ Check if there is a match in mdadm.conf
+	 * 3a/ if not, check for homehost match.  If no match, reject.
+	 * 4/ Determine device number.
+	 * - If in mdadm.conf with std name, use that
+	 * - UUID in /var/run/mdadm.map  use that
+	 * - If name is suggestive, use that. unless in use with different uuid.
+	 * - Choose a free, high number.
+	 * - Use a partitioned device unless strong suggestion not to.
+	 *         e.g. auto=md
+	 * 5/ Find out if array already exists
+	 * 5a/ if it does not
+	 * - choose a name, from mdadm.conf or 'name' field in array.
+	 * - create the array
+	 * - add the device
+	 * 5b/ if it does
+	 * - check one drive in array to make sure metadata is a reasonably
+	 *       close match.  Reject if not (e.g. different type)
+	 * - add the device
+	 * 6/ Make sure /var/run/mdadm.map contains this array.
+	 * 7/ Is there enough devices to possibly start the array?
+	 * 7a/ if not, finish with success.
+	 * 7b/ if yes,
+	 * - read all metadata and arrange devices like -A does
+	 * - if number of OK devices match expected, or -R and there are enough,
+	 *   start the array (auto-readonly).
+	 */
+	struct stat stb;
+	void *super, *super2;
+	struct mdinfo info, info2;
+	struct mddev_ident_s *array_list, *match;
+	char chosen_name[1024];
+	int rv;
+	int devnum;
+	struct map_ent *mp, *map = NULL;
+	int dfd, mdfd;
+	char *avail;
+	int active_disks;
+
+
+	struct createinfo *ci = conf_get_create_info();
+
+	if (autof == 0)
+		autof = ci->autof;
+
+	/* 1/ Check if devices is permitted by mdadm.conf */
+
+	if (!conf_test_dev(devname)) {
+		if (verbose >= 0)
+			fprintf(stderr, Name
+				": %s not permitted by mdadm.conf.\n",
+				devname);
+		return 1;
+	}
+
+	/* 2/ Find metadata, reject if none appropriate (check
+	 *            version/name from args) */
+
+	dfd = dev_open(devname, O_RDONLY|O_EXCL);
+	if (dfd < 0) {
+		if (verbose >= 0)
+			fprintf(stderr, Name ": cannot open %s: %s.\n",
+				devname, strerror(errno));
+		return 1;
+	}
+	if (fstat(dfd, &stb) < 0) {
+		if (verbose >= 0)
+			fprintf(stderr, Name ": fstat failed for %s: %s.\n",
+				devname, strerror(errno));
+		close(dfd);
+		return 1;
+	}
+	if ((stb.st_mode & S_IFMT) != S_IFBLK) {
+		if (verbose >= 0)
+			fprintf(stderr, Name ": %s is not a block device.\n",
+				devname);
+		close(dfd);
+		return 1;
+	}
+
+	if (st == NULL && (st = guess_super(dfd)) == NULL) {
+		if (verbose >= 0)
+			fprintf(stderr, Name
+				": no recognisable superblock on %s.\n",
+				devname);
+		close(dfd);
+		return 1;
+	}
+	if (st->ss->load_super(st, dfd, &super, NULL)) {
+		if (verbose >= 0)
+			fprintf(stderr, Name ": no RAID superblock on %s.\n",
+				devname);
+		close(dfd);
+		return 1;
+	}
+	st->ss->getinfo_super(&info, super);
+	close (dfd);
+
+	/* 3/ Check if there is a match in mdadm.conf */
+
+	array_list = conf_get_ident(NULL);
+	match = NULL;
+	for (; array_list; array_list = array_list->next) {
+		if (array_list->uuid_set &&
+		    same_uuid(array_list->uuid, info.uuid, st->ss->swapuuid)
+		    == 0) {
+			if (verbose >= 2)
+				fprintf(stderr, Name
+					": UUID differs from %s.\n",
+					array_list->devname);
+			continue;
+		}
+		if (array_list->name[0] &&
+		    strcasecmp(array_list->name, info.name) != 0) {
+			if (verbose >= 2)
+				fprintf(stderr, Name
+					": Name differs from %s.\n",
+					array_list->devname);
+			continue;
+		}
+		if (array_list->devices &&
+		    !match_oneof(array_list->devices, devname)) {
+			if (verbose >= 2)
+				fprintf(stderr, Name
+					": Not a listed device for %s.\n",
+					array_list->devname);
+			continue;
+		}
+		if (array_list->super_minor != UnSet &&
+		    array_list->super_minor != info.array.md_minor) {
+			if (verbose >= 2)
+				fprintf(stderr, Name
+					": Different super-minor to %s.\n",
+					array_list->devname);
+			continue;
+		}
+		if (!array_list->uuid_set &&
+		    !array_list->name[0] &&
+		    !array_list->devices &&
+		    array_list->super_minor == UnSet) {
+			if (verbose  >= 2)
+				fprintf(stderr, Name
+			     ": %s doesn't have any identifying information.\n",
+					array_list->devname);
+			continue;
+		}
+		/* FIXME, should I check raid_disks and level too?? */
+
+		if (match) {
+			if (verbose >= 0)
+				fprintf(stderr, Name
+		   ": we match both %s and %s - cannot decide which to use.\n",
+					match->devname, array_list->devname);
+			return 2;
+		}
+		match = array_list;
+	}
+
+	/* 3a/ if not, check for homehost match.  If no match, reject. */
+	if (!match) {
+		if (homehost == NULL ||
+		    st->ss->match_home(super, homehost) == 0) {
+			if (verbose >= 0)
+				fprintf(stderr, Name
+	      ": not found in mdadm.conf and not identified by homehost.\n");
+			return 2;
+		}
+	}
+	/* 4/ Determine device number. */
+	/* - If in mdadm.conf with std name, use that */
+	/* - UUID in /var/run/mdadm.map  use that */
+	/* - If name is suggestive, use that. unless in use with */
+	/*           different uuid. */
+	/* - Choose a free, high number. */
+	/* - Use a partitioned device unless strong suggestion not to. */
+	/*         e.g. auto=md */
+	if (match && is_standard(match->devname, &devnum))
+		/* We have devnum now */;
+	else if ((mp = map_by_uuid(&map, info.uuid)) != NULL)
+		devnum = mp->devnum;
+	else {
+		/* Have to guess a bit. */
+		int use_partitions = 1;
+		char *np, *ep;
+		if ((autof&7) == 3 || (autof&7) == 5)
+			use_partitions = 0;
+		np = strchr(info.name, ':');
+		if (np)
+			np++;
+		else
+			np = info.name;
+		devnum = strtoul(np, &ep, 10);
+		if (ep > np && *ep == 0) {
+			/* This is a number.  Let check that it is unused. */
+			if (mddev_busy(use_partitions ? (-1-devnum) : devnum))
+				devnum = -1;
+		} else
+			devnum = -1;
+
+		if (devnum < 0) {
+			/* Haven't found anything yet, choose something free */
+			/* There is similar code in mdopen.c - should unify */
+			for (devnum = 127 ; devnum != 128 ;
+			     devnum = devnum ? devnum-1 : (1<<22)-1) {
+				if (mddev_busy(use_partitions ?
+					       (-1-devnum) : devnum))
+					break;
+			}
+			if (devnum == 128) {
+				fprintf(stderr, Name
+					": No spare md devices!!\n");
+				return 2;
+			}
+		}
+		devnum = use_partitions ? (-1-devnum) : devnum;
+	}
+	mdfd = open_mddev_devnum(match ? match->devname : NULL,
+				 devnum,
+				 info.name,
+				 chosen_name);
+	if (mdfd < 0) {
+		fprintf(stderr, Name ": failed to open %s: %s.\n",
+			chosen_name, strerror(errno));
+		return 2;
+	}
+	/* 5/ Find out if array already exists */
+	if (! mddev_busy(devnum)) {
+	/* 5a/ if it does not */
+	/* - choose a name, from mdadm.conf or 'name' field in array. */
+	/* - create the array */
+	/* - add the device */
+		mdu_array_info_t ainf;
+		mdu_disk_info_t disk;
+		char md[20];
+		struct sysarray *sra;
+
+		memset(&ainf, 0, sizeof(ainf));
+		ainf.major_version = st->ss->major;
+		ainf.minor_version = st->minor_version;
+		if (ioctl(mdfd, SET_ARRAY_INFO, &ainf) != 0) {
+			fprintf(stderr, Name
+				": SET_ARRAY_INFO failed for %s: %s\b",
+				chosen_name, strerror(errno));
+			close(mdfd);
+			return 2;
+		}
+		sprintf(md, "%d.%d\n", st->ss->major, st->minor_version);
+		sra = sysfs_read(mdfd, devnum, GET_VERSION);
+		sysfs_set_str(sra, NULL, "metadata_version", md);
+		memset(&disk, 0, sizeof(disk));
+		disk.major = major(stb.st_rdev);
+		disk.minor = minor(stb.st_rdev);
+		sysfs_free(sra);
+		if (ioctl(mdfd, ADD_NEW_DISK, &disk) != 0) {
+			fprintf(stderr, Name ": failed to add %s to %s: %s.\n",
+				devname, chosen_name, strerror(errno));
+			ioctl(mdfd, STOP_ARRAY, 0);
+			close(mdfd);
+			return 2;
+		}
+		sra = sysfs_read(mdfd, devnum, GET_DEVS);
+		if (!sra || !sra->devs || sra->devs->role >= 0) {
+			/* It really should be 'none' - must be old buggy
+			 * kernel, and mdadm -I may not be able to complete.
+			 * So reject it.
+			 */
+			ioctl(mdfd, STOP_ARRAY, NULL);
+			fprintf(stderr, Name
+		      ": You have an old buggy kernel which cannot support\n"
+				"      --incremental reliably.  Aborting.\n");
+			close(mdfd);
+			sysfs_free(sra);
+			return 2;
+		}
+	} else {
+	/* 5b/ if it does */
+	/* - check one drive in array to make sure metadata is a reasonably */
+	/*        close match.  Reject if not (e.g. different type) */
+	/* - add the device */
+		char dn[20];
+		int dfd2;
+		mdu_disk_info_t disk;
+		int err;
+		struct sysarray *sra;
+		sra = sysfs_read(mdfd, devnum, (GET_VERSION | GET_DEVS |
+						GET_STATE));
+		if (sra->major_version != st->ss->major ||
+		    sra->minor_version != st->minor_version) {
+			if (verbose >= 0)
+				fprintf(stderr, Name
+	      ": %s has different metadata to chosen array %s %d.%d %d.%d.\n",
+					devname, chosen_name,
+					sra->major_version, sra->minor_version,
+					st->ss->major, st->minor_version);
+			close(mdfd);
+			return 1;
+		}
+		sprintf(dn, "%d:%d", sra->devs->major, sra->devs->minor);
+		dfd2 = dev_open(dn, O_RDONLY);
+		if (st->ss->load_super(st, dfd2,&super2, NULL)) {
+			fprintf(stderr, Name
+				": Strange error loading metadata for %s.\n",
+				chosen_name);
+			close(mdfd);
+			close(dfd2);
+			return 2;
+		}
+		close(dfd2);
+		st->ss->getinfo_super(&info2, super2);
+		if (info.array.level != info2.array.level ||
+		    memcmp(info.uuid, info2.uuid, 16) != 0 ||
+		    info.array.raid_disks != info2.array.raid_disks) {
+			fprintf(stderr, Name
+				": unexpected difference between %s and %s.\n",
+				chosen_name, devname);
+			close(mdfd);
+			return 2;
+		}
+		memset(&disk, 0, sizeof(disk));
+		disk.major = major(stb.st_rdev);
+		disk.minor = minor(stb.st_rdev);
+		err = ioctl(mdfd, ADD_NEW_DISK, &disk);
+		if (err < 0 && errno == EBUSY) {
+			/* could be another device present with the same
+			 * disk.number. Find and reject any such
+			 */
+			find_reject(mdfd, st, sra, info.disk.number,
+				    info.events, verbose, chosen_name);
+			err = ioctl(mdfd, ADD_NEW_DISK, &disk);
+		}
+		if (err < 0) {
+			fprintf(stderr, Name ": failed to add %s to %s: %s.\n",
+				devname, chosen_name, strerror(errno));
+			close(mdfd);
+			return 2;
+		}
+	}
+	/* 6/ Make sure /var/run/mdadm.map contains this array. */
+	map_update(&map, devnum,
+		   info.array.major_version,
+		   info.array.minor_version,
+		   info.uuid, chosen_name);
+
+	/* 7/ Is there enough devices to possibly start the array? */
+	/* 7a/ if not, finish with success. */
+	active_disks = count_active(st, mdfd, &avail, &info);
+	if (enough(info.array.level, info.array.raid_disks,
+		   info.array.layout, info.array.state & 1,
+		   avail, active_disks) == 0) {
+		free(avail);
+		if (verbose >= 0)
+			fprintf(stderr, Name
+			     ": %s attached to %s, not enough to start (%d).\n",
+				devname, chosen_name, active_disks);
+		close(mdfd);
+		return 0;
+	}
+	free(avail);
+
+	/* 7b/ if yes, */
+	/* - if number of OK devices match expected, or -R and there */
+	/*             are enough, */
+	/*   + add any bitmap file  */
+	/*   + start the array (auto-readonly). */
+{
+	mdu_array_info_t ainf;
+
+	if (ioctl(mdfd, GET_ARRAY_INFO, &ainf) == 0) {
+		if (verbose >= 0)
+			fprintf(stderr, Name
+			   ": %s attached to %s which is already active.\n",
+				devname, chosen_name);
+		close (mdfd);
+		return 0;
+	}
+}
+	if (runstop > 0 || active_disks >= info.array.working_disks) {
+		struct sysarray *sra;
+		/* Let's try to start it */
+		if (match && match->bitmap_file) {
+			int bmfd = open(match->bitmap_file, O_RDWR);
+			if (bmfd < 0) {
+				fprintf(stderr, Name
+					": Could not open bitmap file %s.\n",
+					match->bitmap_file);
+				close(mdfd);
+				return 1;
+			}
+			if (ioctl(mdfd, SET_BITMAP_FILE, bmfd) != 0) {
+				close(bmfd);
+				fprintf(stderr, Name
+					": Failed to set bitmapfile for %s.\n",
+					chosen_name);
+				close(mdfd);
+				return 1;
+			}
+			close(bmfd);
+		}
+		sra = sysfs_read(mdfd, devnum, 0);
+		if (sra == NULL || active_disks >= info.array.working_disks)
+			rv = ioctl(mdfd, RUN_ARRAY, NULL);
+		else
+			rv = sysfs_set_str(sra, NULL,
+					   "array_state", "read-auto");
+		if (rv == 0) {
+			if (verbose >= 0)
+				fprintf(stderr, Name
+			   ": %s attached to %s, which has been started.\n",
+					devname, chosen_name);
+			rv = 0;
+		} else {
+			fprintf(stderr, Name
+                             ": %s attached to %s, but failed to start: %s.\n",
+				devname, chosen_name, strerror(errno));
+			rv = 1;
+		}
+	} else {
+		if (verbose >= 0)
+			fprintf(stderr, Name
+                          ": %s attached to %s, not enough to start safely.\n",
+				devname, chosen_name);
+		rv = 0;
+	}
+	close(mdfd);
+	return rv;
+}
+
+static void find_reject(int mdfd, struct supertype *st, struct sysarray *sra,
+			int number, __u64 events, int verbose,
+			char *array_name)
+{
+	/* Find an device attached to this array with a disk.number of number
+	 * and events less than the passed events, and remove the device.
+	 */
+	struct sysdev *d;
+	mdu_array_info_t ra;
+
+	if (ioctl(mdfd, GET_ARRAY_INFO, &ra) == 0)
+		return; /* not safe to remove from active arrays
+			 * without thinking more */
+
+	for (d = sra->devs; d ; d = d->next) {
+		char dn[10];
+		int dfd;
+		void *super;
+		struct mdinfo info;
+		sprintf(dn, "%d:%d", d->major, d->minor);
+		dfd = dev_open(dn, O_RDONLY);
+		if (dfd < 0)
+			continue;
+		if (st->ss->load_super(st, dfd, &super, NULL)) {
+			close(dfd);
+			continue;
+		}
+		st->ss->getinfo_super(&info, super);
+		free(super);
+		close(dfd);
+
+		if (info.disk.number != number ||
+		    info.events >= events)
+			continue;
+
+		if (d->role > -1)
+			sysfs_set_str(sra, d, "slot", "none");
+		if (sysfs_set_str(sra, d, "state", "remove") == 0)
+			if (verbose >= 0)
+				fprintf(stderr, Name
+					": removing old device %s from %s\n",
+					d->name+4, array_name);
+	}
+}
+
+static int count_active(struct supertype *st, int mdfd, char **availp,
+			struct mdinfo *bestinfo)
+{
+	/* count how many devices in sra think they are active */
+	struct sysdev *d;
+	int cnt = 0, cnt1 = 0;
+	__u64 max_events = 0;
+	void *best_super = NULL;
+	struct sysarray *sra = sysfs_read(mdfd, -1, GET_DEVS | GET_STATE);
+	char *avail = NULL;
+
+	for (d = sra->devs ; d ; d = d->next) {
+		char dn[30];
+		int dfd;
+		void *super;
+		int ok;
+		struct mdinfo info;
+
+		sprintf(dn, "%d:%d", d->major, d->minor);
+		dfd = dev_open(dn, O_RDONLY);
+		if (dfd < 0)
+			continue;
+		ok =  st->ss->load_super(st, dfd, &super, NULL);
+		close(dfd);
+		if (ok != 0)
+			continue;
+		st->ss->getinfo_super(&info, super);
+		if (info.disk.state & (1<<MD_DISK_SYNC))
+		{
+			if (avail == NULL) {
+				avail = malloc(info.array.raid_disks);
+				memset(avail, 0, info.array.raid_disks);
+			}
+			if (cnt == 0) {
+				cnt++;
+				max_events = info.events;
+				avail[info.disk.raid_disk] = 2;
+				best_super = super; super = NULL;
+			} else if (info.events == max_events) {
+				cnt++;
+				avail[info.disk.raid_disk] = 2;
+			} else if (info.events == max_events-1) {
+				cnt1++;
+				avail[info.disk.raid_disk] = 1;
+			} else if (info.events < max_events - 1)
+				;
+			else if (info.events == max_events+1) {
+				int i;
+				cnt1 = cnt;
+				cnt = 1;
+				max_events = info.events;
+				for (i=0; i<info.array.raid_disks; i++)
+					if (avail[i])
+						avail[i]--;
+				avail[info.disk.raid_disk] = 2;
+				free(best_super);
+				best_super = super;
+				super = NULL;
+			} else { /* info.events much bigger */
+				cnt = 1; cnt1 = 0;
+				memset(avail, 0, info.disk.raid_disk);
+				max_events = info.events;
+				free(best_super);
+				best_super = super;
+				super = NULL;
+			}
+		}
+		if (super)
+			free(super);
+	}
+	if (best_super) {
+		st->ss->getinfo_super(bestinfo,best_super);
+		free(best_super);
+	}
+	return cnt + cnt1;
+}
+
+void RebuildMap(void)
+{
+	struct mdstat_ent *mdstat = mdstat_read(0, 0);
+	struct mdstat_ent *md;
+	struct map_ent *map = NULL;
+	int mdp = get_mdp_major();
+
+	for (md = mdstat ; md ; md = md->next) {
+		struct sysarray *sra = sysfs_read(-1, md->devnum, GET_DEVS);
+		struct sysdev *sd;
+
+		for (sd = sra->devs ; sd ; sd = sd->next) {
+			char dn[30];
+			int dfd;
+			int ok;
+			struct supertype *st;
+			char *path;
+			void *super;
+			struct mdinfo info;
+
+			sprintf(dn, "%d:%d", sd->major, sd->minor);
+			dfd = dev_open(dn, O_RDONLY);
+			if (dfd < 0)
+				continue;
+			st = guess_super(dfd);
+			if ( st == NULL)
+				ok = -1;
+			else
+				ok = st->ss->load_super(st, dfd, &super, NULL);
+			close(dfd);
+			if (ok != 0)
+				continue;
+			st->ss->getinfo_super(&info, super);
+			if (md->devnum > 0)
+				path = map_dev(MD_MAJOR, md->devnum, 0);
+			else
+				path = map_dev(mdp, (-1-md->devnum)<< 6, 0);
+			map_add(&map, md->devnum, st->ss->major,
+				st->minor_version,
+				info.uuid, path ? : "/unknown");
+			free(super);
+			break;
+		}
+	}
+	map_write(map);
+	map_free(map);
+}
+
+int IncrementalScan(int verbose)
+{
+	/* look at every device listed in the 'map' file.
+	 * If one is found that is not running then:
+	 *  look in mdadm.conf for bitmap file.
+	 *   if one exists, but array has none, add it.
+	 *  try to start array in auto-readonly mode
+	 */
+	struct map_ent *mapl = NULL;
+	struct map_ent *me;
+	mddev_ident_t devs, mddev;
+	int rv = 0;
+
+	map_read(&mapl);
+	devs = conf_get_ident(NULL);
+
+	for (me = mapl ; me ; me = me->next) {
+		char path[1024];
+		mdu_array_info_t array;
+		mdu_bitmap_file_t bmf;
+		struct sysarray *sra;
+		int mdfd = open_mddev_devnum(me->path, me->devnum, NULL, path);
+		if (mdfd < 0)
+			continue;
+		if (ioctl(mdfd, GET_ARRAY_INFO, &array) == 0 ||
+		    errno != ENODEV) {
+			close(mdfd);
+			continue;
+		}
+		/* Ok, we can try this one.   Maybe it needs a bitmap */
+		for (mddev = devs ; mddev ; mddev = mddev->next)
+			if (strcmp(mddev->devname, me->path) == 0)
+				break;
+		if (mddev && mddev->bitmap_file) {
+			/*
+			 * Note: early kernels will wrongly fail this, so it
+			 * is a hint only
+			 */
+			int added = -1;
+			if (ioctl(mdfd, GET_ARRAY_INFO, &bmf) < 0) {
+				int bmfd = open(mddev->bitmap_file, O_RDWR);
+				if (bmfd >= 0) {
+					added = ioctl(mdfd, SET_BITMAP_FILE,
+						      bmfd);
+					close(bmfd);
+				}
+			}
+			if (verbose >= 0) {
+				if (added == 0)
+					fprintf(stderr, Name
+						": Added bitmap %s to %s\n",
+						mddev->bitmap_file, me->path);
+				else if (errno != EEXIST)
+					fprintf(stderr, Name
+					   ": Failed to add bitmap to %s: %s\n",
+						me->path, strerror(errno));
+			}
+		}
+		sra = sysfs_read(mdfd, 0, 0);
+		if (sra) {
+			if (sysfs_set_str(sra, NULL,
+					  "array_state", "read-auto") == 0) {
+				if (verbose >= 0)
+					fprintf(stderr, Name
+						": started array %s\n",
+						me->path);
+			} else {
+				fprintf(stderr, Name
+					": failed to start array %s: %s\n",
+					me->path, strerror(errno));
+				rv = 1;
+			}
+		}
+	}
+	return rv;
+}