Commit 1f27c737 authored by Neil Brown's avatar Neil Brown Committed by Linus Torvalds

[PATCH] md: Add new superblock format for md

Superblock format '1' resolves a number of issues with
superblock format '0'.
It is more dense and can support many more sub-devices.
It does not contains un-needed redundancy.
It adds a few new useful fields
parent a3a173cd
......@@ -763,6 +763,210 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
sb->sb_csum = calc_sb_csum(sb);
}
/*
* version 1 superblock
*/
static unsigned int calc_sb_1_csum(struct mdp_superblock_1 * sb)
{
unsigned int disk_csum, csum;
int size = 256 + sb->max_dev*2;
disk_csum = sb->sb_csum;
sb->sb_csum = 0;
csum = csum_partial((void *)sb, size, 0);
sb->sb_csum = disk_csum;
return csum;
}
static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
{
struct mdp_superblock_1 *sb;
int ret;
sector_t sb_offset;
/*
* Calculate the position of the superblock.
* It is always aligned to a 4K boundary and
* depeding on minor_version, it can be:
* 0: At least 8K, but less than 12K, from end of device
* 1: At start of device
* 2: 4K from start of device.
*/
switch(minor_version) {
case 0:
sb_offset = rdev->bdev->bd_inode->i_size >> 9;
sb_offset -= 8*2;
sb_offset &= ~(4*2);
/* convert from sectors to K */
sb_offset /= 2;
break;
case 1:
sb_offset = 0;
break;
case 2:
sb_offset = 4;
break;
default:
return -EINVAL;
}
rdev->sb_offset = sb_offset;
ret = read_disk_sb(rdev);
if (ret) return ret;
sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
sb->major_version != cpu_to_le32(1) ||
le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
le64_to_cpu(sb->super_offset) != (rdev->sb_offset<<1) ||
sb->feature_map != 0)
return -EINVAL;
if (calc_sb_1_csum(sb) != sb->sb_csum) {
printk(BAD_CSUM, bdev_partition_name(rdev->bdev));
return -EINVAL;
}
rdev->preferred_minor = 0xffff;
rdev->data_offset = le64_to_cpu(sb->data_offset);
if (refdev == 0)
return 1;
else {
__u64 ev1, ev2;
struct mdp_superblock_1 *refsb =
(struct mdp_superblock_1*)page_address(refdev->sb_page);
if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
sb->level != refsb->level ||
sb->layout != refsb->layout ||
sb->chunksize != refsb->chunksize) {
printk(KERN_WARNING "md: %s has strangely different superblock to %s\n",
bdev_partition_name(rdev->bdev),
bdev_partition_name(refdev->bdev));
return -EINVAL;
}
ev1 = le64_to_cpu(sb->events);
ev2 = le64_to_cpu(refsb->events);
if (ev1 > ev2)
return 1;
}
if (minor_version)
rdev->size = ((rdev->bdev->bd_inode->i_size>>9) - le64_to_cpu(sb->data_offset)) / 2;
else
rdev->size = rdev->sb_offset;
if (rdev->size < le64_to_cpu(sb->data_size)/2)
return -EINVAL;
rdev->size = le64_to_cpu(sb->data_size)/2;
if (le32_to_cpu(sb->chunksize))
rdev->size &= ~((sector_t)le32_to_cpu(sb->chunksize)/2 - 1);
return 0;
}
static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
{
struct mdp_superblock_1 *sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
if (mddev->raid_disks == 0) {
mddev->major_version = 1;
mddev->minor_version = 0;
mddev->patch_version = 0;
mddev->persistent = 1;
mddev->chunk_size = le32_to_cpu(sb->chunksize) << 9;
mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
mddev->level = le32_to_cpu(sb->level);
mddev->layout = le32_to_cpu(sb->layout);
mddev->raid_disks = le32_to_cpu(sb->raid_disks);
mddev->size = (u32)le64_to_cpu(sb->size);
mddev->events = le64_to_cpu(sb->events);
mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
memcpy(mddev->uuid, sb->set_uuid, 16);
mddev->max_disks = (4096-256)/2;
} else {
__u64 ev1;
ev1 = le64_to_cpu(sb->events);
++ev1;
if (ev1 < mddev->events)
return -EINVAL;
}
if (mddev->level != LEVEL_MULTIPATH) {
int role;
rdev->desc_nr = le32_to_cpu(sb->dev_number);
role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
switch(role) {
case 0xffff: /* spare */
rdev->in_sync = 0;
rdev->faulty = 0;
rdev->raid_disk = -1;
break;
case 0xfffe: /* faulty */
rdev->in_sync = 0;
rdev->faulty = 1;
rdev->raid_disk = -1;
break;
default:
rdev->in_sync = 1;
rdev->faulty = 0;
rdev->raid_disk = role;
break;
}
}
return 0;
}
static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
{
struct mdp_superblock_1 *sb;
struct list_head *tmp;
mdk_rdev_t *rdev2;
int max_dev, i;
/* make rdev->sb match mddev and rdev data. */
sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
sb->feature_map = 0;
sb->pad0 = 0;
memset(sb->pad1, 0, sizeof(sb->pad1));
memset(sb->pad2, 0, sizeof(sb->pad2));
memset(sb->pad3, 0, sizeof(sb->pad3));
sb->utime = cpu_to_le64((__u64)mddev->utime);
sb->events = cpu_to_le64(mddev->events);
if (mddev->in_sync)
sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
else
sb->resync_offset = cpu_to_le64(0);
max_dev = 0;
ITERATE_RDEV(mddev,rdev2,tmp)
if (rdev2->desc_nr > max_dev)
max_dev = rdev2->desc_nr;
sb->max_dev = max_dev;
for (i=0; i<max_dev;i++)
sb->dev_roles[max_dev] = cpu_to_le16(0xfffe);
ITERATE_RDEV(mddev,rdev2,tmp) {
i = rdev2->desc_nr;
if (rdev2->faulty)
sb->dev_roles[i] = cpu_to_le16(0xfffe);
else if (rdev2->in_sync)
sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
else
sb->dev_roles[i] = cpu_to_le16(0xffff);
}
sb->recovery_offset = cpu_to_le64(0); /* not supported yet */
}
struct super_type super_types[] = {
[0] = {
.name = "0.90.0",
......@@ -771,10 +975,15 @@ struct super_type super_types[] = {
.validate_super = super_90_validate,
.sync_super = super_90_sync,
},
[1] = {
.name = "md-1",
.owner = THIS_MODULE,
.load_super = super_1_load,
.validate_super = super_1_validate,
.sync_super = super_1_sync,
},
};
static mdk_rdev_t * match_dev_unit(mddev_t *mddev, mdk_rdev_t *dev)
{
struct list_head *tmp;
......
......@@ -173,5 +173,58 @@ static inline __u64 md_event(mdp_super_t *sb) {
return (ev<<32)| sb->events_lo;
}
/*
* The version-1 superblock :
* All numeric fields are little-endian.
*
* total size: 256 bytes plus 2 per device.
* 1K allows 384 devices.
*/
struct mdp_superblock_1 {
/* constant array information - 128 bytes */
__u32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */
__u32 major_version; /* 1 */
__u32 feature_map; /* 0 for now */
__u32 pad0; /* always set to 0 when writing */
__u8 set_uuid[16]; /* user-space generated. */
char set_name[32]; /* set and interpreted by user-space */
__u64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/
__u32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */
__u32 layout; /* only for raid5 currently */
__u64 size; /* used size of component devices, in 512byte sectors */
__u32 chunksize; /* in 512byte sectors */
__u32 raid_disks;
__u8 pad1[128-92]; /* set to 0 when written */
/* constant this-device information - 64 bytes */
__u64 data_offset; /* sector start of data, often 0 */
__u64 data_size; /* sectors in this device that can be used for data */
__u64 super_offset; /* sector start of this superblock */
__u64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */
__u32 dev_number; /* permanent identifier of this device - not role in raid */
__u32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */
__u8 device_uuid[16]; /* user-space setable, ignored by kernel */
__u8 pad2[64-56]; /* set to 0 when writing */
/* array state information - 64 bytes */
__u64 utime; /* 40 bits second, 24 btes microseconds */
__u64 events; /* incremented when superblock updated */
__u64 resync_offset; /* data before this offset (from data_offset) known to be in sync */
__u32 sb_csum; /* checksum upto devs[max_dev] */
__u32 max_dev; /* size of devs[] array to consider */
__u8 pad3[64-40]; /* set to 0 when writing */
/* device state information. Indexed by dev_number.
* 2 bytes per device
* Note there are no per-device state flags. State information is rolled
* into the 'roles' value. If a device is spare or faulty, then it doesn't
* have a meaningful role.
*/
__u16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */
};
#endif
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