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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 <marcin.labun@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2009-07-31 17:11:41 -07:00
parent 329c827869
commit 148acb7baa
4 changed files with 48 additions and 16 deletions
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1
mdadm.h
View File

@ -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);

11
super-ddf.c
View File

@ -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;

41
super-intel.c
View File

@ -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) {

11
util.c
View File

@ -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)
{