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imsm: fix spare record writeout race 

imsm_activate_spare() in the manager thread may race against
write_super_imsm_spares() in the monitor thread.  Give
write_super_imsm_spares() its own private mpb buffer to prevent
confusing the manager.

This change uncovered cases where spares were not being assembled due to
a failed metadata version number check.  Spares can freely associate
across metadata version number, so reduce the scope of the version check
in the spare assembly case.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2009-10-13 17:41:53 -07:00
parent a2b9798159
commit f796af5d5e
1 changed files with 35 additions and 24 deletions
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59
super-intel.c
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@ -1477,9 +1477,6 @@ static int compare_super_imsm(struct supertype *st, struct supertype *tst)
return 0;
}
if (memcmp(first->anchor->sig, sec->anchor->sig, MAX_SIGNATURE_LENGTH) != 0)
return 3;
/* if an anchor does not have num_raid_devs set then it is a free
* floating spare
*/
@ -1492,6 +1489,10 @@ static int compare_super_imsm(struct supertype *st, struct supertype *tst)
__u32 first_family = first->anchor->orig_family_num;
__u32 sec_family = sec->anchor->orig_family_num;
if (memcmp(first->anchor->sig, sec->anchor->sig,
MAX_SIGNATURE_LENGTH) != 0)
return 3;
if (first_family == 0)
first_family = first->anchor->family_num;
if (sec_family == 0)
@ -1499,8 +1500,10 @@ static int compare_super_imsm(struct supertype *st, struct supertype *tst)
if (first_family != sec_family)
return 3;
}
/* if 'first' is a spare promote it to a populated mpb with sec's
* family number
*/
@ -2976,39 +2979,48 @@ static int add_to_super_imsm(struct supertype *st, mdu_disk_info_t *dk,
return 0;
}
static int store_imsm_mpb(int fd, struct intel_super *super);
static int store_imsm_mpb(int fd, struct imsm_super *mpb);
static union {
char buf[512];
struct imsm_super anchor;
} spare_record __attribute__ ((aligned(512)));
/* spare records have their own family number and do not have any defined raid
* devices
*/
static int write_super_imsm_spares(struct intel_super *super, int doclose)
{
struct imsm_super mpb_save;
struct imsm_super *mpb = super->anchor;
struct imsm_super *spare = &spare_record.anchor;
__u32 sum;
struct dl *d;
mpb_save = *mpb;
mpb->num_raid_devs = 0;
mpb->num_disks = 1;
mpb->mpb_size = sizeof(struct imsm_super);
mpb->generation_num = __cpu_to_le32(1UL);
spare->mpb_size = __cpu_to_le32(sizeof(struct imsm_super)),
spare->generation_num = __cpu_to_le32(1UL),
spare->attributes = MPB_ATTRIB_CHECKSUM_VERIFY;
spare->num_disks = 1,
spare->num_raid_devs = 0,
spare->cache_size = mpb->cache_size,
spare->pwr_cycle_count = __cpu_to_le32(1),
snprintf((char *) spare->sig, MAX_SIGNATURE_LENGTH,
MPB_SIGNATURE MPB_VERSION_RAID0);
for (d = super->disks; d; d = d->next) {
if (d->index != -1)
continue;
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);
spare->disk[0] = d->disk;
sum = __gen_imsm_checksum(spare);
spare->family_num = __cpu_to_le32(sum);
spare->orig_family_num = 0;
sum = __gen_imsm_checksum(spare);
spare->check_sum = __cpu_to_le32(sum);
if (store_imsm_mpb(d->fd, super)) {
if (store_imsm_mpb(d->fd, spare)) {
fprintf(stderr, "%s: failed for device %d:%d %s\n",
__func__, d->major, d->minor, strerror(errno));
*mpb = mpb_save;
return 1;
}
if (doclose) {
@ -3017,7 +3029,6 @@ static int write_super_imsm_spares(struct intel_super *super, int doclose)
}
}
*mpb = mpb_save;
return 0;
}
@ -3069,7 +3080,7 @@ static int write_super_imsm(struct intel_super *super, int doclose)
for (d = super->disks; d ; d = d->next) {
if (d->index < 0)
continue;
if (store_imsm_mpb(d->fd, super))
if (store_imsm_mpb(d->fd, mpb))
fprintf(stderr, "%s: failed for device %d:%d %s\n",
__func__, d->major, d->minor, strerror(errno));
if (doclose) {
@ -4144,9 +4155,9 @@ static void imsm_set_disk(struct active_array *a, int n, int state)
}
}
static int store_imsm_mpb(int fd, struct intel_super *super)
static int store_imsm_mpb(int fd, struct imsm_super *mpb)
{
struct imsm_super *mpb = super->anchor;
void *buf = mpb;
__u32 mpb_size = __le32_to_cpu(mpb->mpb_size);
unsigned long long dsize;
unsigned long long sectors;
@ -4161,7 +4172,7 @@ static int store_imsm_mpb(int fd, struct intel_super *super)
if (lseek64(fd, dsize - (512 * (2 + sectors)), SEEK_SET) < 0)
return 1;
if (write(fd, super->buf + 512, 512 * sectors) != 512 * sectors)
if (write(fd, buf + 512, 512 * sectors) != 512 * sectors)
return 1;
}
@ -4169,7 +4180,7 @@ static int store_imsm_mpb(int fd, struct intel_super *super)
if (lseek64(fd, dsize - (512 * 2), SEEK_SET) < 0)
return 1;
if (write(fd, super->buf, 512) != 512)
if (write(fd, buf, 512) != 512)
return 1;
return 0;