From: Dan Williams Date: Sat, 1 Aug 2009 00:11:41 +0000 (-0700) Subject: imsm: fix family number handling X-Git-Tag: mdadm-3.0.1~6^2~3 X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fmdadm.git;a=commitdiff_plain;h=148acb7baaa810b68d55df4c1784d6bd0dfd1b78 imsm: fix family number handling The family_number field can change. The option-rom will change the family number when it starts a rebuild process (flags a container for rebuild). This was not seen previously as mdadm would usually start the rebuild process, preserving the family number. This is the mechanism that helps to prevent a prodigal array member from being returned to its original system and cause a rebuild to go in the wrong direction. With the change we will end up with a container that will fail to assemble unless the device with the incompatible family number is left out of the assembly. So, take several actions: 1/ Convert uuid generation to use orig_family_num, being careful to preserve the existing uuid in the case where orig_family_num is not set (i.e. previous mdadm created imsm arrays) 2/ Set orig_family_num at Create. For arrays created by mdadm prior to this release orig_family_num will be zero, so set it to family_num at the first metadata write. 3/ Add checks for orig_family_num to compare_super_imsm 4/ Update the family number when initiating rebuild 5/ The option-rom mixes some random data into the family number, add this functionality to the mdadm implementation. Reported-by: Marcin Labun Signed-off-by: Dan Williams --- diff --git a/mdadm.h b/mdadm.h index e564deea..4111eafa 100644 --- a/mdadm.h +++ b/mdadm.h @@ -848,6 +848,7 @@ extern int open_container(int fd); extern int mdmon_running(int devnum); extern int signal_mdmon(int devnum); extern int check_env(char *name); +extern __u32 random32(void); extern int start_mdmon(int devnum); extern char *devnum2devname(int num); diff --git a/super-ddf.c b/super-ddf.c index 0b152759..c28d8040 100644 --- a/super-ddf.c +++ b/super-ddf.c @@ -1512,17 +1512,6 @@ static int update_super_ddf(struct supertype *st, struct mdinfo *info, return rv; } -__u32 random32(void) -{ - __u32 rv; - int rfd = open("/dev/urandom", O_RDONLY); - if (rfd < 0 || read(rfd, &rv, 4) != 4) - rv = random(); - if (rfd >= 0) - close(rfd); - return rv; -} - static void make_header_guid(char *guid) { __u32 stamp; diff --git a/super-intel.c b/super-intel.c index 07e3d46c..6e4a7d90 100644 --- a/super-intel.c +++ b/super-intel.c @@ -247,6 +247,7 @@ struct intel_super { int creating_imsm; /* flag to indicate container creation */ int current_vol; /* index of raid device undergoing creation */ __u32 create_offset; /* common start for 'current_vol' */ + __u32 random; /* random data for seeding new family numbers */ struct intel_dev *devlist; struct dl { struct dl *next; @@ -714,6 +715,7 @@ static void examine_super_imsm(struct supertype *st, char *homehost) printf(" Magic : %s\n", str); snprintf(str, strlen(MPB_VERSION_RAID0), "%s", get_imsm_version(mpb)); printf(" Version : %s\n", get_imsm_version(mpb)); + printf(" Orig Family : %08x\n", __le32_to_cpu(mpb->orig_family_num)); printf(" Family : %08x\n", __le32_to_cpu(mpb->family_num)); printf(" Generation : %08x\n", __le32_to_cpu(mpb->generation_num)); getinfo_super_imsm(st, &info); @@ -1091,7 +1093,7 @@ static int match_home_imsm(struct supertype *st, char *homehost) /* the imsm metadata format does not specify any host * identification information. We return -1 since we can never * confirm nor deny whether a given array is "meant" for this - * host. We rely on compare_super and the 'family_num' field to + * host. We rely on compare_super and the 'family_num' fields to * exclude member disks that do not belong, and we rely on * mdadm.conf to specify the arrays that should be assembled. * Auto-assembly may still pick up "foreign" arrays. @@ -1119,7 +1121,7 @@ static void uuid_from_super_imsm(struct supertype *st, int uuid[4]) */ /* imsm does not track uuid's so we synthesis one using sha1 on * - The signature (Which is constant for all imsm array, but no matter) - * - the family_num of the container + * - the orig_family_num of the container * - the index number of the volume * - the 'serial' number of the volume. * Hopefully these are all constant. @@ -1129,10 +1131,18 @@ static void uuid_from_super_imsm(struct supertype *st, int uuid[4]) char buf[20]; struct sha1_ctx ctx; struct imsm_dev *dev = NULL; + __u32 family_num; + /* some mdadm versions failed to set ->orig_family_num, in which + * case fall back to ->family_num. orig_family_num will be + * fixed up with the first metadata update. + */ + family_num = super->anchor->orig_family_num; + if (family_num == 0) + family_num = super->anchor->family_num; sha1_init_ctx(&ctx); sha1_process_bytes(super->anchor->sig, MPB_SIG_LEN, &ctx); - sha1_process_bytes(&super->anchor->family_num, sizeof(__u32), &ctx); + sha1_process_bytes(&family_num, sizeof(__u32), &ctx); if (super->current_vol >= 0) dev = get_imsm_dev(super, super->current_vol); if (dev) { @@ -1440,7 +1450,8 @@ static int compare_super_imsm(struct supertype *st, struct supertype *tst) */ if (first->anchor->num_raid_devs > 0 && sec->anchor->num_raid_devs > 0) { - if (first->anchor->family_num != sec->anchor->family_num) + if (first->anchor->orig_family_num != sec->anchor->orig_family_num || + first->anchor->family_num != sec->anchor->family_num) return 3; } @@ -1480,6 +1491,7 @@ static int compare_super_imsm(struct supertype *st, struct supertype *tst) imsm_copy_dev(get_imsm_dev(first, i), get_imsm_dev(sec, i)); first->anchor->num_raid_devs = sec->anchor->num_raid_devs; + first->anchor->orig_family_num = sec->anchor->orig_family_num; first->anchor->family_num = sec->anchor->family_num; } @@ -2549,8 +2561,10 @@ static int add_to_super_imsm_volume(struct supertype *st, mdu_disk_info_t *dk, *_dev = *dev; *_disk = dl->disk; - sum = __gen_imsm_checksum(mpb); + sum = random32(); + sum += __gen_imsm_checksum(mpb); mpb->family_num = __cpu_to_le32(sum); + mpb->orig_family_num = mpb->family_num; } return 0; @@ -2647,6 +2661,7 @@ static int write_super_imsm_spares(struct intel_super *super, int doclose) mpb->disk[0] = d->disk; sum = __gen_imsm_checksum(mpb); mpb->family_num = __cpu_to_le32(sum); + mpb->orig_family_num = 0; sum = __gen_imsm_checksum(mpb); mpb->check_sum = __cpu_to_le32(sum); @@ -2681,6 +2696,12 @@ static int write_super_imsm(struct intel_super *super, int doclose) generation++; mpb->generation_num = __cpu_to_le32(generation); + /* fix up cases where previous mdadm releases failed to set + * orig_family_num + */ + if (mpb->orig_family_num == 0) + mpb->orig_family_num = mpb->family_num; + mpb_size += sizeof(struct imsm_disk) * mpb->num_disks; for (d = super->disks; d; d = d->next) { if (d->index == -1) @@ -4040,6 +4061,7 @@ static struct mdinfo *imsm_activate_spare(struct active_array *a, di->data_offset = __le32_to_cpu(map->pba_of_lba0); di->component_size = a->info.component_size; di->container_member = inst; + super->random = random32(); di->next = rv; rv = di; num_spares++; @@ -4206,6 +4228,15 @@ static void imsm_process_update(struct supertype *st, set_imsm_ord_tbl_ent(map, u->slot, dl->index); set_imsm_ord_tbl_ent(migr_map, u->slot, dl->index | IMSM_ORD_REBUILD); + /* update the family_num to mark a new container + * generation, being careful to record the existing + * family_num in orig_family_num to clean up after + * earlier mdadm versions that neglected to set it. + */ + if (mpb->orig_family_num == 0) + mpb->orig_family_num = mpb->family_num; + mpb->family_num += super->random; + /* count arrays using the victim in the metadata */ found = 0; for (a = st->arrays; a ; a = a->next) { diff --git a/util.c b/util.c index 00bf8037..25439710 100644 --- a/util.c +++ b/util.c @@ -1298,6 +1298,17 @@ int check_env(char *name) return 0; } +__u32 random32(void) +{ + __u32 rv; + int rfd = open("/dev/urandom", O_RDONLY); + if (rfd < 0 || read(rfd, &rv, 4) != 4) + rv = random(); + if (rfd >= 0) + close(rfd); + return rv; +} + #ifndef MDASSEMBLE int flush_metadata_updates(struct supertype *st) {