mdopen.c - pub/scm/utils/mdadm/mdadm - Git at Google

 /*
  * mdadm - manage Linux "md" devices aka RAID arrays.
  *
  * Copyright (C) 2001-2013 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>
  */

 #include "mdadm.h"
 #include "md_p.h"
 #include <ctype.h>

 void make_parts(char *dev, int cnt)
 {
 	/* make 'cnt' partition devices for 'dev'
 	 * If dev is a device name we use the
 	 *  major/minor from dev and add 1..cnt
 	 * If it is a symlink, we make similar symlinks.
 	 * If dev ends with a digit, we add "p%d" else "%d"
 	 * If the name exists, we use it's owner/mode,
 	 * else that of dev
 	 */
 	struct stat stb;
 	int major_num;
 	int minor_num;
 	int odig;
 	int i;
 	int nlen = strlen(dev) + 20;
 	char *name;
 	int dig = isdigit(dev[strlen(dev)-1]);
 	char orig[1001];
 	char sym[1024];
 	int err;

 	if (cnt == 0)
 		cnt = 4;
 	if (lstat(dev, &stb)!= 0)
 		return;

 	if (S_ISBLK(stb.st_mode)) {
 		major_num = major(stb.st_rdev);
 		minor_num = minor(stb.st_rdev);
 		odig = -1;
 	} else if (S_ISLNK(stb.st_mode)) {
 		int len;

 		len = readlink(dev, orig, sizeof(orig));
 		if (len < 0 || len >= (int)sizeof(orig))
 			return;
 		orig[len] = 0;
 		odig = isdigit(orig[len-1]);
 		major_num = -1;
 		minor_num = -1;
 	} else
 		return;
 	name = xmalloc(nlen);
 	for (i = 1; i <= cnt ; i++) {
 		struct stat stb2;
 		snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
 		if (stat(name, &stb2) == 0) {
 			if (!S_ISBLK(stb2.st_mode) || !S_ISBLK(stb.st_mode))
 				continue;
 			if (stb2.st_rdev == makedev(major_num, minor_num+i))
 				continue;
 			unlink(name);
 		} else {
 			stb2 = stb;
 		}
 		if (S_ISBLK(stb.st_mode)) {
 			if (mknod(name, S_IFBLK | 0600,
 				  makedev(major_num, minor_num+i)))
 				perror("mknod");
 			if (chown(name, stb2.st_uid, stb2.st_gid))
 				perror("chown");
 			if (chmod(name, stb2.st_mode & 07777))
 				perror("chmod");
 			err = 0;
 		} else {
 			snprintf(sym, sizeof(sym), "%s%s%d", orig, odig?"p":"", i);
 			err = symlink(sym, name);
 		}

 		if (err == 0 && stat(name, &stb2) == 0)
 			add_dev(name, &stb2, 0, NULL);
 	}
 	free(name);
 }

 int create_named_array(char *devnm)
 {
 	int fd;
 	int n = -1;
 	static const char new_array_file[] = {
 		"/sys/module/md_mod/parameters/new_array"
 	};

 	fd = open(new_array_file, O_WRONLY);
 	if (fd < 0 && errno == ENOENT) {
 		if (system("modprobe md_mod") == 0)
 			fd = open(new_array_file, O_WRONLY);
 	}
 	if (fd >= 0) {
 		n = write(fd, devnm, strlen(devnm));
 		close(fd);
 	}
 	if (fd < 0 || n != (int)strlen(devnm)) {
 		pr_err("Fail to create %s when using %s, fallback to creation via node\n",
 			devnm, new_array_file);
 		return 0;
 	}

 	return 1;
 }

 /*
  * We need a new md device to assemble/build/create an array.
  * 'dev' is a name given us by the user (command line or mdadm.conf)
  * It might start with /dev or /dev/md any might end with a digit
  * string.
  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
  * If it ends with a digit string, then it must be as above, or
  * 'trustworthy' must be 'METADATA' and the 'dev' must be
  *  /dev/md/'name'NN or 'name'NN
  * If it doesn't end with a digit string, it must be /dev/md/'name'
  * or 'name' or must be NULL.
  * If the digit string is present, it gives the minor number to use
  * If not, we choose a high, unused minor number.
  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
  * else if the name is 'd[0-9]+' then we use mdp
  * else if trustworthy is 'METADATA' we use md
  * else the choice depends on 'autof'.
  * If name is NULL it is assumed to match whatever dev provides.
  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
  *
  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
  * supported by 'dev', we add a "_%d" suffix based on the minor number
  * use that.
  *
  * If udev is configured, we create a temporary device, open it, and
  * unlink it.
  * If not, we create the /dev/mdXX device, and if name is usable,
  * /dev/md/name
  * In any case we return /dev/md/name or (if that isn't available)
  * /dev/mdXX in 'chosen'.
  *
  * When we create devices, we use uid/gid/umask from config file.
  */

 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 		 char *chosen, int block_udev)
 {
 	int mdfd;
 	struct stat stb;
 	int num = -1;
 	int use_mdp = -1;
 	struct createinfo *ci = conf_get_create_info();
 	int parts;
 	char *cname;
 	char devname[37];
 	char devnm[32];
 	char cbuf[400];

 	if (!use_udev())
 		block_udev = 0;

 	if (chosen == NULL)
 		chosen = cbuf;

 	if (autof == 0)
 		autof = ci->autof;

 	parts = autof >> 3;
 	autof &= 7;

 	strcpy(chosen, "/dev/md/");
 	cname = chosen + strlen(chosen);

 	if (dev) {
 		if (strncmp(dev, "/dev/md/", 8) == 0) {
 			strcpy(cname, dev+8);
 		} else if (strncmp(dev, "/dev/", 5) == 0) {
 			char *e = dev + strlen(dev);
 			while (e > dev && isdigit(e[-1]))
 				e--;
 			if (e[0])
 				num = strtoul(e, NULL, 10);
 			strcpy(cname, dev+5);
 			cname[e-(dev+5)] = 0;
 			/* name *must* be mdXX or md_dXX in this context */
 			if (num < 0 ||
 			    (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 				pr_err("%s is an invalid name for an md device.  Try /dev/md/%s\n",
 					dev, dev+5);
 				return -1;
 			}
 			if (strcmp(cname, "md") == 0)
 				use_mdp = 0;
 			else
 				use_mdp = 1;
 			/* recreate name: /dev/md/0 or /dev/md/d0 */
 			sprintf(cname, "%s%d", use_mdp?"d":"", num);
 		} else
 			strcpy(cname, dev);

 		/* 'cname' must not contain a slash, and may not be
 		 * empty.
 		 */
 		if (strchr(cname, '/') != NULL) {
 			pr_err("%s is an invalid name for an md device.\n", dev);
 			return -1;
 		}
 		if (cname[0] == 0) {
 			pr_err("%s is an invalid name for an md device (empty!).\n", dev);
 			return -1;
 		}
 		if (num < 0) {
 			/* If cname  is 'N' or 'dN', we get dev number
 			 * from there.
 			 */
 			char *sp = cname;
 			char *ep;
 			if (cname[0] == 'd')
 				sp++;
 			if (isdigit(sp[0]))
 				num = strtoul(sp, &ep, 10);
 			else
 				ep = sp;
 			if (ep == sp || *ep || num < 0)
 				num = -1;
 			else if (cname[0] == 'd')
 				use_mdp = 1;
 			else
 				use_mdp = 0;
 		}
 	}

 	/* Now determine device number */
 	/* named 'METADATA' cannot use 'mdp'. */
 	if (name && name[0] == 0)
 		name = NULL;
 	if (name && trustworthy == METADATA && use_mdp == 1) {
 		pr_err("%s is not allowed for a %s container. Consider /dev/md%d.\n", dev, name, num);
 		return -1;
 	}
 	if (name && trustworthy == METADATA)
 		use_mdp = 0;
 	if (use_mdp == -1) {
 		if (autof == 4 || autof == 6)
 			use_mdp = 1;
 		else
 			use_mdp = 0;
 	}
 	if (num < 0 && trustworthy == LOCAL && name) {
 		/* if name is numeric, possibly prefixed by
 		 * 'md' or '/dev/md', use that for num
 		 * if it is not already in use */
 		char *ep;
 		char *n2 = name;
 		if (strncmp(n2, "/dev/", 5) == 0)
 			n2 += 5;
 		if (strncmp(n2, "md", 2) == 0)
 			n2 += 2;
 		if (*n2 == '/')
 			n2++;
 		num = strtoul(n2, &ep, 10);
 		if (ep == n2 || *ep)
 			num = -1;
 		else {
 			sprintf(devnm, "md%s%d", use_mdp ? "_d":"", num);
 			if (mddev_busy(devnm))
 				num = -1;
 		}
 	}

 	if (cname[0] == 0 && name) {
 		/* Need to find a name if we can
 		 * We don't completely trust 'name'.  Truncate to
 		 * reasonable length and remove '/'
 		 */
 		char *cp;
 		struct map_ent *map = NULL;
 		int conflict = 1;
 		int unum = 0;
 		int cnlen;
 		strncpy(cname, name, 200);
 		cname[200] = 0;
 		for (cp = cname; *cp ; cp++)
 			switch (*cp) {
 			case '/':
 				*cp = '-';
 				break;
 			case ' ':
 			case '\t':
 				*cp = '_';
 				break;
 			}

 		if (trustworthy == LOCAL ||
 		    (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 			/* Only need suffix if there is a conflict */
 			if (map_by_name(&map, cname) == NULL)
 				conflict = 0;
 		}
 		cnlen = strlen(cname);
 		while (conflict) {
 			if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 				sprintf(cname+cnlen, "%d", unum);
 			else
 				/* add _%d to FOREIGN array that don't
 				 * a 'host:' prefix
 				 */
 				sprintf(cname+cnlen, "_%d", unum);
 			unum++;
 			if (map_by_name(&map, cname) == NULL)
 				conflict = 0;
 		}
 	}

 	devnm[0] = 0;
 	if (num < 0 && cname && ci->names) {
 		sprintf(devnm, "md_%s", cname);
 		if (block_udev)
 			udev_block(devnm);
 		if (!create_named_array(devnm)) {
 			devnm[0] = 0;
 			udev_unblock();
 		}
 	}
 	if (num >= 0) {
 		sprintf(devnm, "md%d", num);
 		if (block_udev)
 			udev_block(devnm);
 		if (!create_named_array(devnm)) {
 			devnm[0] = 0;
 			udev_unblock();
 		}
 	}
 	if (devnm[0] == 0) {
 		if (num < 0) {
 			/* need to choose a free number. */
 			char *_devnm = find_free_devnm(use_mdp);
 			if (_devnm == NULL) {
 				pr_err("No avail md devices - aborting\n");
 				return -1;
 			}
 			strcpy(devnm, _devnm);
 		} else {
 			sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
 			if (mddev_busy(devnm)) {
 				pr_err("%s is already in use.\n",
 				       dev);
 				return -1;
 			}
 		}
 		if (block_udev)
 			udev_block(devnm);
 	}

 	sprintf(devname, "/dev/%s", devnm);

 	if (dev && dev[0] == '/')
 		strcpy(chosen, dev);
 	else if (cname[0] == 0)
 		strcpy(chosen, devname);

 	/* We have a device number and name.
 	 * If we cannot detect udev, we need to make
 	 * devices and links ourselves.
 	 */
 	if (!use_udev()) {
 		/* Make sure 'devname' exists and 'chosen' is a symlink to it */
 		if (lstat(devname, &stb) == 0) {
 			/* Must be the correct device, else error */
 			if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 			    stb.st_rdev != devnm2devid(devnm)) {
 				pr_err("%s exists but looks wrong, please fix\n",
 					devname);
 				return -1;
 			}
 		} else {
 			if (mknod(devname, S_IFBLK|0600,
 				  devnm2devid(devnm)) != 0) {
 				pr_err("failed to create %s\n",
 					devname);
 				return -1;
 			}
 			if (chown(devname, ci->uid, ci->gid))
 				perror("chown");
 			if (chmod(devname, ci->mode))
 				perror("chmod");
 			stat(devname, &stb);
 			add_dev(devname, &stb, 0, NULL);
 		}
 		if (use_mdp == 1)
 			make_parts(devname, parts);

 		if (strcmp(chosen, devname) != 0) {
 			if (mkdir("/dev/md",0700) == 0) {
 				if (chown("/dev/md", ci->uid, ci->gid))
 					perror("chown /dev/md");
 				if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 					perror("chmod /dev/md");
 			}

 			if (dev && strcmp(chosen, dev) == 0)
 				/* We know we are allowed to use this name */
 				unlink(chosen);

 			if (lstat(chosen, &stb) == 0) {
 				char buf[300];
 				ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
 				if (link_len >= 0)
 					buf[link_len] = '\0';

 				if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 				    link_len < 0 ||
 				    strcmp(buf, devname) != 0) {
 					pr_err("%s exists - ignoring\n",
 						chosen);
 					strcpy(chosen, devname);
 				}
 			} else if (symlink(devname, chosen) != 0)
 				pr_err("failed to create %s: %s\n",
 					chosen, strerror(errno));
 			if (use_mdp && strcmp(chosen, devname) != 0)
 				make_parts(chosen, parts);
 		}
 	}
 	mdfd = open_dev_excl(devnm);
 	if (mdfd < 0)
 		pr_err("unexpected failure opening %s\n",
 			devname);
 	return mdfd;
 }

 /* Open this and check that it is an md device.
  * On success, return filedescriptor.
  * On failure, return -1 if it doesn't exist,
  * or -2 if it exists but is not an md device.
  */
 int open_mddev(char *dev, int report_errors)
 {
 	int mdfd = open(dev, O_RDONLY);

 	if (mdfd < 0) {
 		if (report_errors)
 			pr_err("error opening %s: %s\n",
 				dev, strerror(errno));
 		return -1;
 	}

 	if (md_array_valid(mdfd) == 0) {
 		close(mdfd);
 		if (report_errors)
 			pr_err("%s does not appear to be an md device\n", dev);
 		return -2;
 	}

 	return mdfd;
 }

 char *find_free_devnm(int use_partitions)
 {
 	static char devnm[32];
 	int devnum;
 	for (devnum = 127; devnum != 128;
 	     devnum = devnum ? devnum-1 : (1<<9)-1) {

 		if (use_partitions)
 			sprintf(devnm, "md_d%d", devnum);
 		else
 			sprintf(devnm, "md%d", devnum);
 		if (mddev_busy(devnm))
 			continue;
 		if (!conf_name_is_free(devnm))
 			continue;
 		if (!use_udev()) {
 			/* make sure it is new to /dev too, at least as a
 			 * non-standard */
 			dev_t devid = devnm2devid(devnm);
 			if (devid) {
 				char *dn = map_dev(major(devid),
 						   minor(devid), 0);
 				if (dn && ! is_standard(dn, NULL))
 					continue;
 			}
 		}
 		break;
 	}
 	if (devnum == 128)
 		return NULL;
 	return devnm;
 }
	/*
	* mdadm - manage Linux "md" devices aka RAID arrays.
	*
	* Copyright (C) 2001-2013 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>
	*/

	#include "mdadm.h"
	#include "md_p.h"
	#include <ctype.h>

	void make_parts(char *dev, int cnt)
	{
	/* make 'cnt' partition devices for 'dev'
	* If dev is a device name we use the
	* major/minor from dev and add 1..cnt
	* If it is a symlink, we make similar symlinks.
	* If dev ends with a digit, we add "p%d" else "%d"
	* If the name exists, we use it's owner/mode,
	* else that of dev
	*/
	struct stat stb;
	int major_num;
	int minor_num;
	int odig;
	int i;
	int nlen = strlen(dev) + 20;
	char *name;
	int dig = isdigit(dev[strlen(dev)-1]);
	char orig[1001];
	char sym[1024];
	int err;

	if (cnt == 0)
	cnt = 4;
	if (lstat(dev, &stb)!= 0)
	return;

	if (S_ISBLK(stb.st_mode)) {
	major_num = major(stb.st_rdev);
	minor_num = minor(stb.st_rdev);
	odig = -1;
	} else if (S_ISLNK(stb.st_mode)) {
	int len;

	len = readlink(dev, orig, sizeof(orig));
	if (len < 0 \|\| len >= (int)sizeof(orig))
	return;
	orig[len] = 0;
	odig = isdigit(orig[len-1]);
	major_num = -1;
	minor_num = -1;
	} else
	return;
	name = xmalloc(nlen);
	for (i = 1; i <= cnt ; i++) {
	struct stat stb2;
	snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
	if (stat(name, &stb2) == 0) {
	if (!S_ISBLK(stb2.st_mode) \|\| !S_ISBLK(stb.st_mode))
	continue;
	if (stb2.st_rdev == makedev(major_num, minor_num+i))
	continue;
	unlink(name);
	} else {
	stb2 = stb;
	}
	if (S_ISBLK(stb.st_mode)) {
	if (mknod(name, S_IFBLK \| 0600,
	makedev(major_num, minor_num+i)))
	perror("mknod");
	if (chown(name, stb2.st_uid, stb2.st_gid))
	perror("chown");
	if (chmod(name, stb2.st_mode & 07777))
	perror("chmod");
	err = 0;
	} else {
	snprintf(sym, sizeof(sym), "%s%s%d", orig, odig?"p":"", i);
	err = symlink(sym, name);
	}

	if (err == 0 && stat(name, &stb2) == 0)
	add_dev(name, &stb2, 0, NULL);
	}
	free(name);
	}

	int create_named_array(char *devnm)
	{
	int fd;
	int n = -1;
	static const char new_array_file[] = {
	"/sys/module/md_mod/parameters/new_array"
	};

	fd = open(new_array_file, O_WRONLY);
	if (fd < 0 && errno == ENOENT) {
	if (system("modprobe md_mod") == 0)
	fd = open(new_array_file, O_WRONLY);
	}
	if (fd >= 0) {
	n = write(fd, devnm, strlen(devnm));
	close(fd);
	}
	if (fd < 0 \|\| n != (int)strlen(devnm)) {
	pr_err("Fail to create %s when using %s, fallback to creation via node\n",
	devnm, new_array_file);
	return 0;
	}

	return 1;
	}

	/*
	* We need a new md device to assemble/build/create an array.
	* 'dev' is a name given us by the user (command line or mdadm.conf)
	* It might start with /dev or /dev/md any might end with a digit
	* string.
	* If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
	* If it ends with a digit string, then it must be as above, or
	* 'trustworthy' must be 'METADATA' and the 'dev' must be
	* /dev/md/'name'NN or 'name'NN
	* If it doesn't end with a digit string, it must be /dev/md/'name'
	* or 'name' or must be NULL.
	* If the digit string is present, it gives the minor number to use
	* If not, we choose a high, unused minor number.
	* If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
	* else if the name is 'd[0-9]+' then we use mdp
	* else if trustworthy is 'METADATA' we use md
	* else the choice depends on 'autof'.
	* If name is NULL it is assumed to match whatever dev provides.
	* If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
	*
	* If 'name' is given, and 'trustworthy' is 'foreign' and name is not
	* supported by 'dev', we add a "_%d" suffix based on the minor number
	* use that.
	*
	* If udev is configured, we create a temporary device, open it, and
	* unlink it.
	* If not, we create the /dev/mdXX device, and if name is usable,
	* /dev/md/name
	* In any case we return /dev/md/name or (if that isn't available)
	* /dev/mdXX in 'chosen'.
	*
	* When we create devices, we use uid/gid/umask from config file.
	*/

	int create_mddev(char dev, char name, int autof, int trustworthy,
	char *chosen, int block_udev)
	{
	int mdfd;
	struct stat stb;
	int num = -1;
	int use_mdp = -1;
	struct createinfo *ci = conf_get_create_info();
	int parts;
	char *cname;
	char devname[37];
	char devnm[32];
	char cbuf[400];

	if (!use_udev())
	block_udev = 0;

	if (chosen == NULL)
	chosen = cbuf;

	if (autof == 0)
	autof = ci->autof;

	parts = autof >> 3;
	autof &= 7;

	strcpy(chosen, "/dev/md/");
	cname = chosen + strlen(chosen);

	if (dev) {
	if (strncmp(dev, "/dev/md/", 8) == 0) {
	strcpy(cname, dev+8);
	} else if (strncmp(dev, "/dev/", 5) == 0) {
	char *e = dev + strlen(dev);
	while (e > dev && isdigit(e[-1]))
	e--;
	if (e[0])
	num = strtoul(e, NULL, 10);
	strcpy(cname, dev+5);
	cname[e-(dev+5)] = 0;
	/* name must be mdXX or md_dXX in this context */
	if (num < 0 \|\|
	(strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
	pr_err("%s is an invalid name for an md device. Try /dev/md/%s\n",
	dev, dev+5);
	return -1;
	}
	if (strcmp(cname, "md") == 0)
	use_mdp = 0;
	else
	use_mdp = 1;
	/* recreate name: /dev/md/0 or /dev/md/d0 */
	sprintf(cname, "%s%d", use_mdp?"d":"", num);
	} else
	strcpy(cname, dev);

	/* 'cname' must not contain a slash, and may not be
	* empty.
	*/
	if (strchr(cname, '/') != NULL) {
	pr_err("%s is an invalid name for an md device.\n", dev);
	return -1;
	}
	if (cname[0] == 0) {
	pr_err("%s is an invalid name for an md device (empty!).\n", dev);
	return -1;
	}
	if (num < 0) {
	/* If cname is 'N' or 'dN', we get dev number
	* from there.
	*/
	char *sp = cname;
	char *ep;
	if (cname[0] == 'd')
	sp++;
	if (isdigit(sp[0]))
	num = strtoul(sp, &ep, 10);
	else
	ep = sp;
	if (ep == sp \|\| *ep \|\| num < 0)
	num = -1;
	else if (cname[0] == 'd')
	use_mdp = 1;
	else
	use_mdp = 0;
	}
	}

	/* Now determine device number */
	/* named 'METADATA' cannot use 'mdp'. */
	if (name && name[0] == 0)
	name = NULL;
	if (name && trustworthy == METADATA && use_mdp == 1) {
	pr_err("%s is not allowed for a %s container. Consider /dev/md%d.\n", dev, name, num);
	return -1;
	}
	if (name && trustworthy == METADATA)
	use_mdp = 0;
	if (use_mdp == -1) {
	if (autof == 4 \|\| autof == 6)
	use_mdp = 1;
	else
	use_mdp = 0;
	}
	if (num < 0 && trustworthy == LOCAL && name) {
	/* if name is numeric, possibly prefixed by
	* 'md' or '/dev/md', use that for num
	* if it is not already in use */
	char *ep;
	char *n2 = name;
	if (strncmp(n2, "/dev/", 5) == 0)
	n2 += 5;
	if (strncmp(n2, "md", 2) == 0)
	n2 += 2;
	if (*n2 == '/')
	n2++;
	num = strtoul(n2, &ep, 10);
	if (ep == n2 \|\| *ep)
	num = -1;
	else {
	sprintf(devnm, "md%s%d", use_mdp ? "_d":"", num);
	if (mddev_busy(devnm))
	num = -1;
	}
	}

	if (cname[0] == 0 && name) {
	/* Need to find a name if we can
	* We don't completely trust 'name'. Truncate to
	* reasonable length and remove '/'
	*/
	char *cp;
	struct map_ent *map = NULL;
	int conflict = 1;
	int unum = 0;
	int cnlen;
	strncpy(cname, name, 200);
	cname[200] = 0;
	for (cp = cname; *cp ; cp++)
	switch (*cp) {
	case '/':
	*cp = '-';
	break;
	case ' ':
	case '\t':
	*cp = '_';
	break;
	}

	if (trustworthy == LOCAL \|\|
	(trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
	/* Only need suffix if there is a conflict */
	if (map_by_name(&map, cname) == NULL)
	conflict = 0;
	}
	cnlen = strlen(cname);
	while (conflict) {
	if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
	sprintf(cname+cnlen, "%d", unum);
	else
	/* add _%d to FOREIGN array that don't
	* a 'host:' prefix
	*/
	sprintf(cname+cnlen, "_%d", unum);
	unum++;
	if (map_by_name(&map, cname) == NULL)
	conflict = 0;
	}
	}

	devnm[0] = 0;
	if (num < 0 && cname && ci->names) {
	sprintf(devnm, "md_%s", cname);
	if (block_udev)
	udev_block(devnm);
	if (!create_named_array(devnm)) {
	devnm[0] = 0;
	udev_unblock();
	}
	}
	if (num >= 0) {
	sprintf(devnm, "md%d", num);
	if (block_udev)
	udev_block(devnm);
	if (!create_named_array(devnm)) {
	devnm[0] = 0;
	udev_unblock();
	}
	}
	if (devnm[0] == 0) {
	if (num < 0) {
	/* need to choose a free number. */
	char *_devnm = find_free_devnm(use_mdp);
	if (_devnm == NULL) {
	pr_err("No avail md devices - aborting\n");
	return -1;
	}
	strcpy(devnm, _devnm);
	} else {
	sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
	if (mddev_busy(devnm)) {
	pr_err("%s is already in use.\n",
	dev);
	return -1;
	}
	}
	if (block_udev)
	udev_block(devnm);
	}

	sprintf(devname, "/dev/%s", devnm);

	if (dev && dev[0] == '/')
	strcpy(chosen, dev);
	else if (cname[0] == 0)
	strcpy(chosen, devname);

	/* We have a device number and name.
	* If we cannot detect udev, we need to make
	* devices and links ourselves.
	*/
	if (!use_udev()) {
	/* Make sure 'devname' exists and 'chosen' is a symlink to it */
	if (lstat(devname, &stb) == 0) {
	/* Must be the correct device, else error */
	if ((stb.st_mode&S_IFMT) != S_IFBLK \|\|
	stb.st_rdev != devnm2devid(devnm)) {
	pr_err("%s exists but looks wrong, please fix\n",
	devname);
	return -1;
	}
	} else {
	if (mknod(devname, S_IFBLK\|0600,
	devnm2devid(devnm)) != 0) {
	pr_err("failed to create %s\n",
	devname);
	return -1;
	}
	if (chown(devname, ci->uid, ci->gid))
	perror("chown");
	if (chmod(devname, ci->mode))
	perror("chmod");
	stat(devname, &stb);
	add_dev(devname, &stb, 0, NULL);
	}
	if (use_mdp == 1)
	make_parts(devname, parts);

	if (strcmp(chosen, devname) != 0) {
	if (mkdir("/dev/md",0700) == 0) {
	if (chown("/dev/md", ci->uid, ci->gid))
	perror("chown /dev/md");
	if (chmod("/dev/md", ci->mode\| ((ci->mode>>2) & 0111)))
	perror("chmod /dev/md");
	}

	if (dev && strcmp(chosen, dev) == 0)
	/* We know we are allowed to use this name */
	unlink(chosen);

	if (lstat(chosen, &stb) == 0) {
	char buf[300];
	ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
	if (link_len >= 0)
	buf[link_len] = '\0';

	if ((stb.st_mode & S_IFMT) != S_IFLNK \|\|
	link_len < 0 \|\|
	strcmp(buf, devname) != 0) {
	pr_err("%s exists - ignoring\n",
	chosen);
	strcpy(chosen, devname);
	}
	} else if (symlink(devname, chosen) != 0)
	pr_err("failed to create %s: %s\n",
	chosen, strerror(errno));
	if (use_mdp && strcmp(chosen, devname) != 0)
	make_parts(chosen, parts);
	}
	}
	mdfd = open_dev_excl(devnm);
	if (mdfd < 0)
	pr_err("unexpected failure opening %s\n",
	devname);
	return mdfd;
	}

	/* Open this and check that it is an md device.
	* On success, return filedescriptor.
	* On failure, return -1 if it doesn't exist,
	* or -2 if it exists but is not an md device.
	*/
	int open_mddev(char *dev, int report_errors)
	{
	int mdfd = open(dev, O_RDONLY);

	if (mdfd < 0) {
	if (report_errors)
	pr_err("error opening %s: %s\n",
	dev, strerror(errno));
	return -1;
	}

	if (md_array_valid(mdfd) == 0) {
	close(mdfd);
	if (report_errors)
	pr_err("%s does not appear to be an md device\n", dev);
	return -2;
	}

	return mdfd;
	}

	char *find_free_devnm(int use_partitions)
	{
	static char devnm[32];
	int devnum;
	for (devnum = 127; devnum != 128;
	devnum = devnum ? devnum-1 : (1<<9)-1) {

	if (use_partitions)
	sprintf(devnm, "md_d%d", devnum);
	else
	sprintf(devnm, "md%d", devnum);
	if (mddev_busy(devnm))
	continue;
	if (!conf_name_is_free(devnm))
	continue;
	if (!use_udev()) {
	/* make sure it is new to /dev too, at least as a
	* non-standard */
	dev_t devid = devnm2devid(devnm);
	if (devid) {
	char *dn = map_dev(major(devid),
	minor(devid), 0);
	if (dn && ! is_standard(dn, NULL))
	continue;
	}
	}
	break;
	}
	if (devnum == 128)
	return NULL;
	return devnm;
	}