diff options
Diffstat (limited to '')
| -rw-r--r-- | mapfile.c | 511 |
1 files changed, 511 insertions, 0 deletions
diff --git a/mapfile.c b/mapfile.c new file mode 100644 index 0000000..6b2207d --- /dev/null +++ b/mapfile.c @@ -0,0 +1,511 @@ +/* + * mapfile - keep track of uuid <-> array mapping. Part of: + * mdadm - manage Linux "md" devices aka RAID arrays. + * + * Copyright (C) 2006-2010 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 + */ + +/* The mapfile is used to track arrays being created in --incremental + * mode. It particularly allows lookup from UUID to array device, but + * also allows the array device name to be easily found. + * + * The map file is line based with space separated fields. The fields are: + * Device id - mdX or mdpX where X is a number. + * metadata - 0.90 1.0 1.1 1.2 ddf ... + * UUID - uuid of the array + * path - path where device created: /dev/md/home + * + * The best place for the mapfile is /run/mdadm/map. Distros and users + * which have not switched to /run yet can choose a different location + * at compile time via MAP_DIR and MAP_FILE. + */ +#include "mdadm.h" +#include <sys/file.h> +#include <ctype.h> + +#define MAP_READ 0 +#define MAP_NEW 1 +#define MAP_LOCK 2 +#define MAP_DIRNAME 3 + +char *mapname[4] = { + MAP_DIR "/" MAP_FILE, + MAP_DIR "/" MAP_FILE ".new", + MAP_DIR "/" MAP_FILE ".lock", + MAP_DIR +}; + +int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT|O_TRUNC }; +char *mapsmode[3] = { "r", "w", "w"}; + +FILE *open_map(int modenum) +{ + int fd; + if ((mapmode[modenum] & O_CREAT)) + /* Attempt to create directory, don't worry about + * failure. + */ + (void)mkdir(mapname[MAP_DIRNAME], 0755); + fd = open(mapname[modenum], mapmode[modenum], 0600); + if (fd >= 0) + return fdopen(fd, mapsmode[modenum]); + return NULL; +} + +int map_write(struct map_ent *mel) +{ + FILE *f; + int err; + + f = open_map(MAP_NEW); + + if (!f) + return 0; + for (; mel; mel = mel->next) { + if (mel->bad) + continue; + fprintf(f, "%s ", mel->devnm); + fprintf(f, "%s ", mel->metadata); + fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0], + mel->uuid[1], mel->uuid[2], mel->uuid[3]); + fprintf(f, "%s\n", mel->path?:""); + } + fflush(f); + err = ferror(f); + fclose(f); + if (err) { + unlink(mapname[1]); + return 0; + } + return rename(mapname[1], + mapname[0]) == 0; +} + +static FILE *lf = NULL; +int map_lock(struct map_ent **melp) +{ + while (lf == NULL) { + struct stat buf; + lf = open_map(MAP_LOCK); + if (lf == NULL) + return -1; + if (flock(fileno(lf), LOCK_EX) != 0) { + fclose(lf); + lf = NULL; + return -1; + } + if (fstat(fileno(lf), &buf) != 0 || + buf.st_nlink == 0) { + /* The owner of the lock unlinked it, + * so we have a lock on a stale file, + * try again + */ + fclose(lf); + lf = NULL; + } + } + if (*melp) + map_free(*melp); + map_read(melp); + return 0; +} + +void map_unlock(struct map_ent **melp) +{ + if (lf) { + /* must unlink before closing the file, + * as only the owner of the lock may + * unlink the file + */ + unlink(mapname[2]); + fclose(lf); + } + if (*melp) + map_free(*melp); + lf = NULL; +} + +void map_fork(void) +{ + /* We are forking, so must close the lock file. + * Don't risk flushing anything though. + */ + if (lf) { + close(fileno(lf)); + fclose(lf); + lf = NULL; + } +} + +void map_add(struct map_ent **melp, + char * devnm, char *metadata, int uuid[4], char *path) +{ + struct map_ent *me = xmalloc(sizeof(*me)); + + strcpy(me->devnm, devnm); + strcpy(me->metadata, metadata); + memcpy(me->uuid, uuid, 16); + me->path = path ? xstrdup(path) : NULL; + me->next = *melp; + me->bad = 0; + *melp = me; +} + +void map_read(struct map_ent **melp) +{ + FILE *f; + char buf[8192]; + char path[201]; + int uuid[4]; + char devnm[32]; + char metadata[30]; + + *melp = NULL; + + f = open_map(MAP_READ); + if (!f) { + RebuildMap(); + f = open_map(MAP_READ); + } + if (!f) + return; + + while (fgets(buf, sizeof(buf), f)) { + path[0] = 0; + if (sscanf(buf, " %s %s %x:%x:%x:%x %200s", + devnm, metadata, uuid, uuid+1, + uuid+2, uuid+3, path) >= 7) { + map_add(melp, devnm, metadata, uuid, path); + } + } + fclose(f); +} + +void map_free(struct map_ent *map) +{ + while (map) { + struct map_ent *mp = map; + map = mp->next; + free(mp->path); + free(mp); + } +} + +int map_update(struct map_ent **mpp, char *devnm, char *metadata, + int uuid[4], char *path) +{ + struct map_ent *map, *mp; + int rv; + + if (mpp && *mpp) + map = *mpp; + else + map_read(&map); + + for (mp = map ; mp ; mp=mp->next) + if (strcmp(mp->devnm, devnm) == 0) { + strcpy(mp->metadata, metadata); + memcpy(mp->uuid, uuid, 16); + free(mp->path); + mp->path = path ? xstrdup(path) : NULL; + mp->bad = 0; + break; + } + if (!mp) + map_add(&map, devnm, metadata, uuid, path); + if (mpp) + *mpp = NULL; + rv = map_write(map); + map_free(map); + return rv; +} + +void map_delete(struct map_ent **mapp, char *devnm) +{ + struct map_ent *mp; + + if (*mapp == NULL) + map_read(mapp); + + for (mp = *mapp; mp; mp = *mapp) { + if (strcmp(mp->devnm, devnm) == 0) { + *mapp = mp->next; + free(mp->path); + free(mp); + } else + mapp = & mp->next; + } +} + +void map_remove(struct map_ent **mapp, char *devnm) +{ + if (devnm[0] == 0) + return; + + map_delete(mapp, devnm); + map_write(*mapp); + map_free(*mapp); + *mapp = NULL; +} + +struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4]) +{ + struct map_ent *mp; + if (!*map) + map_read(map); + + for (mp = *map ; mp ; mp = mp->next) { + if (memcmp(uuid, mp->uuid, 16) != 0) + continue; + if (!mddev_busy(mp->devnm)) { + mp->bad = 1; + continue; + } + return mp; + } + return NULL; +} + +struct map_ent *map_by_devnm(struct map_ent **map, char *devnm) +{ + struct map_ent *mp; + if (!*map) + map_read(map); + + for (mp = *map ; mp ; mp = mp->next) { + if (strcmp(mp->devnm, devnm) != 0) + continue; + if (!mddev_busy(mp->devnm)) { + mp->bad = 1; + continue; + } + return mp; + } + return NULL; +} + +struct map_ent *map_by_name(struct map_ent **map, char *name) +{ + struct map_ent *mp; + if (!*map) + map_read(map); + + for (mp = *map ; mp ; mp = mp->next) { + if (!mp->path) + continue; + if (strncmp(mp->path, "/dev/md/", 8) != 0) + continue; + if (strcmp(mp->path+8, name) != 0) + continue; + if (!mddev_busy(mp->devnm)) { + mp->bad = 1; + continue; + } + return mp; + } + return NULL; +} + +/* sets the proper subarray and container_dev according to the metadata + * version super_by_fd does this automatically, this routine is meant as + * a supplement for guess_super() + */ +static char *get_member_info(struct mdstat_ent *ent) +{ + + if (ent->metadata_version == NULL || + strncmp(ent->metadata_version, "external:", 9) != 0) + return NULL; + + if (is_subarray(&ent->metadata_version[9])) { + char *subarray; + + subarray = strrchr(ent->metadata_version, '/'); + return subarray + 1; + } + return NULL; +} + +void RebuildMap(void) +{ + struct mdstat_ent *mdstat = mdstat_read(0, 0); + struct mdstat_ent *md; + struct map_ent *map = NULL; + int require_homehost; + char sys_hostname[256]; + char *homehost = conf_get_homehost(&require_homehost); + + if (homehost == NULL || strcmp(homehost, "<system>")==0) { + if (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) { + sys_hostname[sizeof(sys_hostname)-1] = 0; + homehost = sys_hostname; + } + } + + for (md = mdstat ; md ; md = md->next) { + struct mdinfo *sra = sysfs_read(-1, md->devnm, GET_DEVS); + struct mdinfo *sd; + + if (!sra) + continue; + + for (sd = sra->devs ; sd ; sd = sd->next) { + char namebuf[100]; + char dn[30]; + int dfd; + int ok; + dev_t devid; + struct supertype *st; + char *subarray = NULL; + char *path; + struct mdinfo *info; + + sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor); + dfd = dev_open(dn, O_RDONLY); + if (dfd < 0) + continue; + st = guess_super(dfd); + if ( st == NULL) + ok = -1; + else { + subarray = get_member_info(md); + ok = st->ss->load_super(st, dfd, NULL); + } + close(dfd); + if (ok != 0) + continue; + if (subarray) + info = st->ss->container_content(st, subarray); + else { + info = xmalloc(sizeof(*info)); + st->ss->getinfo_super(st, info, NULL); + } + if (!info) + continue; + + devid = devnm2devid(md->devnm); + path = map_dev(major(devid), minor(devid), 0); + if (path == NULL || + strncmp(path, "/dev/md/", 8) != 0) { + /* We would really like a name that provides + * an MD_DEVNAME for udev. + * The name needs to be unique both in /dev/md/ + * and in this mapfile. + * It needs to match what -I or -As would come + * up with. + * That means: + * Check if array is in mdadm.conf + * - if so use that. + * determine trustworthy from homehost etc + * find a unique name based on metadata name. + * + */ + struct mddev_ident *match = conf_match(st, info, + NULL, 0, + NULL); + struct stat stb; + if (match && match->devname && match->devname[0] == '/') { + path = match->devname; + if (path[0] != '/') { + strcpy(namebuf, "/dev/md/"); + strcat(namebuf, path); + path = namebuf; + } + } else { + int unum = 0; + char *sep = "_"; + const char *name; + int conflict = 1; + if ((homehost == NULL || + st->ss->match_home(st, homehost) != 1) && + st->ss->match_home(st, "any") != 1 && + (require_homehost || + !conf_name_is_free(info->name))) + /* require a numeric suffix */ + unum = 0; + else + /* allow name to be used as-is if no conflict */ + unum = -1; + name = info->name; + if (!*name) { + name = st->ss->name; + if (!isdigit(name[strlen(name)-1]) && + unum == -1) { + unum = 0; + sep = ""; + } + } + if (strchr(name, ':')) { + /* Probably a uniquifying + * hostname prefix. Allow + * without a suffix, and strip + * hostname if it is us. + */ + if (homehost && unum == -1 && + strncmp(name, homehost, + strlen(homehost)) == 0 && + name[strlen(homehost)] == ':') + name += strlen(homehost)+1; + unum = -1; + } + + while (conflict) { + if (unum >= 0) + sprintf(namebuf, "/dev/md/%s%s%d", + name, sep, unum); + else + sprintf(namebuf, "/dev/md/%s", + name); + unum++; + if (lstat(namebuf, &stb) != 0 && + (map == NULL || + !map_by_name(&map, namebuf+8))) + conflict = 0; + } + path = namebuf; + } + } + map_add(&map, md->devnm, + info->text_version, + info->uuid, path); + st->ss->free_super(st); + free(info); + break; + } + sysfs_free(sra); + } + /* Only trigger a change if we wrote a new map file */ + if (map_write(map)) + for (md = mdstat ; md ; md = md->next) { + struct mdinfo *sra = sysfs_read(-1, md->devnm, + GET_VERSION); + if (sra) + sysfs_uevent(sra, "change"); + sysfs_free(sra); + } + map_free(map); + free_mdstat(mdstat); +} |