When reshaping we can avoid costly intermediate backup by
changing the 'start' address of the array on the device
(if there is enough room).
So as a first step, allow such a change to be requested
through sysfs, and recorded in v1.x metadata.
(As we didn't previous check that all 'pad' fields were zero,
we need a new FEATURE flag for this.
A (belatedly) check that all remaining 'pad' fields are
zero to avoid a repeat of this)
The new data offset must be requested separately for each device.
This allows each to have a different change in the data offset.
This is not likely to be used often but as data_offset can be
set per-device, new_data_offset should be too.
This patch also removes the 'acknowledged' arg to rdev_set_badblocks as
it is never used and never will be. At the same time we add a new
arg ('in_new') which is currently always zero but will be used more
soon.
When a reshape finishes we will need to update the data_offset
and rdev->sectors. So provide an exported function to do that.
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
drivers/md/md.c | 220 +++++++++++++++++++++++++++++++++++++++++----
drivers/md/md.h | 7 +
drivers/md/raid1.c | 4 -
drivers/md/raid10.c | 8 +-
drivers/md/raid5.c | 10 +-
include/linux/raid/md_p.h | 10 ++
6 files changed, 225 insertions(+), 34 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 1ea2e26..0db613d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1033,12 +1033,17 @@ static unsigned int calc_sb_csum(mdp_super_t * sb)
struct super_type {
char *name;
struct module *owner;
- int (*load_super)(struct md_rdev *rdev, struct md_rdev *refdev,
+ int (*load_super)(struct md_rdev *rdev,
+ struct md_rdev *refdev,
int minor_version);
- int (*validate_super)(struct mddev *mddev, struct md_rdev *rdev);
- void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
+ int (*validate_super)(struct mddev *mddev,
+ struct md_rdev *rdev);
+ void (*sync_super)(struct mddev *mddev,
+ struct md_rdev *rdev);
unsigned long long (*rdev_size_change)(struct md_rdev *rdev,
sector_t num_sectors);
+ int (*allow_new_offset)(struct md_rdev *rdev,
+ unsigned long long new_offset);
};
/*
@@ -1110,6 +1115,7 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
rdev->preferred_minor = sb->md_minor;
rdev->data_offset = 0;
+ rdev->new_data_offset = 0;
rdev->sb_size = MD_SB_BYTES;
rdev->badblocks.shift = -1;
@@ -1436,6 +1442,12 @@ super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
return num_sectors;
}
+static int
+super_90_allow_new_offset(struct md_rdev *rdev, unsigned long long new_offset)
+{
+ /* non-zero offset changes not possible with v0.90 */
+ return new_offset == 0;
+}
/*
* version 1 superblock
@@ -1471,6 +1483,7 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
struct mdp_superblock_1 *sb;
int ret;
sector_t sb_start;
+ sector_t sectors;
char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
int bmask;
@@ -1525,9 +1538,18 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
bdevname(rdev->bdev,b));
return -EINVAL;
}
+ if (sb->pad0 ||
+ sb->pad3[0] ||
+ memcmp(sb->pad3, sb->pad3+1, sizeof(sb->pad3) - sizeof(sb->pad3[1])))
+ /* Some padding is non-zero, might be a new feature */
+ return -EINVAL;
rdev->preferred_minor = 0xffff;
rdev->data_offset = le64_to_cpu(sb->data_offset);
+ rdev->new_data_offset = rdev->data_offset;
+ if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE) &&
+ (le32_to_cpu(sb->feature_map) & MD_FEATURE_NEW_OFFSET))
+ rdev->new_data_offset += (s32)le32_to_cpu(sb->new_offset);
atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
@@ -1538,6 +1560,9 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
if (minor_version
&& rdev->data_offset < sb_start + (rdev->sb_size/512))
return -EINVAL;
+ if (minor_version
+ && rdev->new_data_offset < sb_start + (rdev->sb_size/512))
+ return -EINVAL;
if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
rdev->desc_nr = -1;
@@ -1609,16 +1634,17 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
else
ret = 0;
}
- if (minor_version)
- rdev->sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
- le64_to_cpu(sb->data_offset);
- else
- rdev->sectors = rdev->sb_start;
- if (rdev->sectors < le64_to_cpu(sb->data_size))
+ if (minor_version) {
+ sectors = (i_size_read(rdev->bdev->bd_inode) >> 9);
+ if (rdev->data_offset > rdev->new_data_offset)
+ sectors -= rdev->data_offset;
+ else
+ sectors -= rdev->new_data_offset;
+ } else
+ sectors = rdev->sb_start;
+ if (sectors < le64_to_cpu(sb->data_size))
return -EINVAL;
rdev->sectors = le64_to_cpu(sb->data_size);
- if (le64_to_cpu(sb->size) > rdev->sectors)
- return -EINVAL;
return ret;
}
@@ -1743,7 +1769,6 @@ static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
sb->feature_map = 0;
sb->pad0 = 0;
sb->recovery_offset = cpu_to_le64(0);
- memset(sb->pad1, 0, sizeof(sb->pad1));
memset(sb->pad3, 0, sizeof(sb->pad3));
sb->utime = cpu_to_le64((__u64)mddev->utime);
@@ -1765,6 +1790,8 @@ static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
sb->devflags |= WriteMostly1;
else
sb->devflags &= ~WriteMostly1;
+ sb->data_offset = cpu_to_le64(rdev->data_offset);
+ sb->data_size = cpu_to_le64(rdev->sectors);
if (mddev->bitmap && mddev->bitmap_info.file == NULL) {
sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_info.offset);
@@ -1793,6 +1820,12 @@ static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
mddev->reshape_backwards)
sb->feature_map
|= cpu_to_le32(MD_FEATURE_RESHAPE_BACKWARDS);
+ if (rdev->new_data_offset != rdev->data_offset) {
+ sb->feature_map
+ |= cpu_to_le32(MD_FEATURE_NEW_OFFSET);
+ sb->new_offset = cpu_to_le32((__u32)(rdev->new_data_offset
+ - rdev->data_offset));
+ }
}
if (rdev->badblocks.count == 0)
@@ -1869,6 +1902,8 @@ super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
sector_t max_sectors;
if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
return 0; /* component must fit device */
+ if (rdev->data_offset != rdev->new_data_offset)
+ return 0; /* too confusing */
if (rdev->sb_start < rdev->data_offset) {
/* minor versions 1 and 2; superblock before data */
max_sectors = i_size_read(rdev->bdev->bd_inode) >> 9;
@@ -1896,6 +1931,40 @@ super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
rdev->sb_page);
md_super_wait(rdev->mddev);
return num_sectors;
+
+}
+
+static int
+super_1_allow_new_offset(struct md_rdev *rdev,
+ unsigned long long new_offset)
+{
+ /* All necessary checks on new >= old have been done */
+ struct bitmap *bitmap;
+ if (new_offset >= rdev->data_offset)
+ return 1;
+
+ /* with 1.0 metadata, there is no metadata to tread on
+ * so we can always move back */
+ if (rdev->mddev->minor_version == 0)
+ return 1;
+
+ /* otherwise we must be sure not to step on
+ * any metadata, so stay:
+ * 36K beyond start of superblock
+ * beyond end of badblocks
+ * beyond write-intent bitmap
+ */
+ if (rdev->sb_start + (32+4)*2 > new_offset)
+ return 0;
+ bitmap = rdev->mddev->bitmap;
+ if (bitmap && !rdev->mddev->bitmap_info.file &&
+ rdev->sb_start + rdev->mddev->bitmap_info.offset +
+ bitmap->file_pages * (PAGE_SIZE>>9) > new_offset)
+ return 0;
+ if (rdev->badblocks.sector + rdev->badblocks.size > new_offset)
+ return 0;
+
+ return 1;
}
static struct super_type super_types[] = {
@@ -1906,6 +1975,7 @@ static struct super_type super_types[] = {
.validate_super = super_90_validate,
.sync_super = super_90_sync,
.rdev_size_change = super_90_rdev_size_change,
+ .allow_new_offset = super_90_allow_new_offset,
},
[1] = {
.name = "md-1",
@@ -1914,6 +1984,7 @@ static struct super_type super_types[] = {
.validate_super = super_1_validate,
.sync_super = super_1_sync,
.rdev_size_change = super_1_rdev_size_change,
+ .allow_new_offset = super_1_allow_new_offset,
},
};
@@ -2821,9 +2892,8 @@ offset_show(struct md_rdev *rdev, char *page)
static ssize_t
offset_store(struct md_rdev *rdev, const char *buf, size_t len)
{
- char *e;
- unsigned long long offset = simple_strtoull(buf, &e, 10);
- if (e==buf || (*e && *e != '\n'))
+ unsigned long long offset;
+ if (strict_strtoull(buf, 10, &offset) < 0)
return -EINVAL;
if (rdev->mddev->pers && rdev->raid_disk >= 0)
return -EBUSY;
@@ -2838,6 +2908,63 @@ offset_store(struct md_rdev *rdev, const char *buf, size_t len)
static struct rdev_sysfs_entry rdev_offset =
__ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
+static ssize_t new_offset_show(struct md_rdev *rdev, char *page)
+{
+ return sprintf(page, "%llu\n",
+ (unsigned long long)rdev->new_data_offset);
+}
+
+static ssize_t new_offset_store(struct md_rdev *rdev,
+ const char *buf, size_t len)
+{
+ unsigned long long new_offset;
+ struct mddev *mddev = rdev->mddev;
+
+ if (strict_strtoull(buf, 10, &new_offset) < 0)
+ return -EINVAL;
+
+ if (mddev->sync_thread)
+ return -EBUSY;
+ if (new_offset == rdev->data_offset)
+ /* reset is always permitted */
+ ;
+ else if (new_offset > rdev->data_offset) {
+ /* must not push array size beyond rdev_sectors */
+ if (new_offset - rdev->data_offset
+ + mddev->dev_sectors > rdev->sectors)
+ return -E2BIG;
+ }
+ /* Metadata worries about other space details. */
+
+ /* decreasing the offset is inconsistent with a backwards
+ * reshape.
+ */
+ if (new_offset < rdev->data_offset &&
+ mddev->reshape_backwards)
+ return -EINVAL;
+ /* Increasing offset is inconsistent with forwards
+ * reshape. reshape_direction should be set to
+ * 'backwards' first.
+ */
+ if (new_offset > rdev->data_offset &&
+ !mddev->reshape_backwards)
+ return -EINVAL;
+
+ if (mddev->pers && mddev->persistent &&
+ !super_types[mddev->major_version]
+ .allow_new_offset(rdev, new_offset))
+ return -E2BIG;
+ rdev->new_data_offset = new_offset;
+ if (new_offset > rdev->data_offset)
+ mddev->reshape_backwards = 1;
+ else if (new_offset < rdev->data_offset)
+ mddev->reshape_backwards = 0;
+
+ return len;
+}
+static struct rdev_sysfs_entry rdev_new_offset =
+__ATTR(new_offset, S_IRUGO|S_IWUSR, new_offset_show, new_offset_store);
+
static ssize_t
rdev_size_show(struct md_rdev *rdev, char *page)
{
@@ -2882,6 +3009,8 @@ rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len)
if (strict_blocks_to_sectors(buf, §ors) < 0)
return -EINVAL;
+ if (rdev->data_offset != rdev->new_data_offset)
+ return -EINVAL; /* too confusing */
if (my_mddev->pers && rdev->raid_disk >= 0) {
if (my_mddev->persistent) {
sectors = super_types[my_mddev->major_version].
@@ -3018,6 +3147,7 @@ static struct attribute *rdev_default_attrs[] = {
&rdev_errors.attr,
&rdev_slot.attr,
&rdev_offset.attr,
+ &rdev_new_offset.attr,
&rdev_size.attr,
&rdev_recovery_start.attr,
&rdev_bad_blocks.attr,
@@ -3092,6 +3222,7 @@ int md_rdev_init(struct md_rdev *rdev)
rdev->raid_disk = -1;
rdev->flags = 0;
rdev->data_offset = 0;
+ rdev->new_data_offset = 0;
rdev->sb_events = 0;
rdev->last_read_error.tv_sec = 0;
rdev->last_read_error.tv_nsec = 0;
@@ -3596,7 +3727,17 @@ raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
if (mddev->pers)
rv = update_raid_disks(mddev, n);
else if (mddev->reshape_position != MaxSector) {
+ struct md_rdev *rdev;
int olddisks = mddev->raid_disks - mddev->delta_disks;
+
+ rdev_for_each(rdev, mddev) {
+ if (olddisks < n &&
+ rdev->data_offset < rdev->new_data_offset)
+ return -EINVAL;
+ if (olddisks > n &&
+ rdev->data_offset > rdev->new_data_offset)
+ return -EINVAL;
+ }
mddev->delta_disks = n - olddisks;
mddev->raid_disks = n;
mddev->reshape_backwards = (mddev->delta_disks < 0);
@@ -4443,6 +4584,7 @@ reshape_position_show(struct mddev *mddev, char *page)
static ssize_t
reshape_position_store(struct mddev *mddev, const char *buf, size_t len)
{
+ struct md_rdev *rdev;
char *e;
unsigned long long new = simple_strtoull(buf, &e, 10);
if (mddev->pers)
@@ -4455,6 +4597,8 @@ reshape_position_store(struct mddev *mddev, const char *buf, size_t len)
mddev->new_level = mddev->level;
mddev->new_layout = mddev->layout;
mddev->new_chunk_sectors = mddev->chunk_sectors;
+ rdev_for_each(rdev, mddev)
+ rdev->new_data_offset = rdev->data_offset;
return len;
}
@@ -5999,6 +6143,7 @@ static int update_size(struct mddev *mddev, sector_t num_sectors)
static int update_raid_disks(struct mddev *mddev, int raid_disks)
{
int rv;
+ struct md_rdev *rdev;
/* change the number of raid disks */
if (mddev->pers->check_reshape == NULL)
return -EINVAL;
@@ -6007,6 +6152,16 @@ static int update_raid_disks(struct mddev *mddev, int raid_disks)
return -EINVAL;
if (mddev->sync_thread || mddev->reshape_position != MaxSector)
return -EBUSY;
+
+ rdev_for_each(rdev, mddev) {
+ if (mddev->raid_disks < raid_disks &&
+ rdev->data_offset < rdev->new_data_offset)
+ return -EINVAL;
+ if (mddev->raid_disks > raid_disks &&
+ rdev->data_offset > rdev->new_data_offset)
+ return -EINVAL;
+ }
+
mddev->delta_disks = raid_disks - mddev->raid_disks;
if (mddev->delta_disks < 0)
mddev->reshape_backwards = 1;
@@ -7707,6 +7862,20 @@ void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev)
}
EXPORT_SYMBOL(md_wait_for_blocked_rdev);
+void md_finish_reshape(struct mddev *mddev)
+{
+ /* called be personality module when reshape completes. */
+ struct md_rdev *rdev;
+
+ rdev_for_each(rdev, mddev) {
+ if (rdev->data_offset > rdev->new_data_offset)
+ rdev->sectors += rdev->data_offset - rdev->new_data_offset;
+ else
+ rdev->sectors -= rdev->new_data_offset - rdev->data_offset;
+ rdev->data_offset = rdev->new_data_offset;
+ }
+}
+EXPORT_SYMBOL(md_finish_reshape);
/* Bad block management.
* We can record which blocks on each device are 'bad' and so just
@@ -7955,10 +8124,15 @@ static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
}
int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
- int acknowledged)
+ int is_new)
{
- int rv = md_set_badblocks(&rdev->badblocks,
- s + rdev->data_offset, sectors, acknowledged);
+ int rv;
+ if (is_new)
+ s += rdev->new_data_offset;
+ else
+ s += rdev->data_offset;
+ rv = md_set_badblocks(&rdev->badblocks,
+ s, sectors, 0);
if (rv) {
/* Make sure they get written out promptly */
sysfs_notify_dirent_safe(rdev->sysfs_state);
@@ -8064,11 +8238,15 @@ out:
return rv;
}
-int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors)
+int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
+ int is_new)
{
+ if (is_new)
+ s += rdev->new_data_offset;
+ else
+ s += rdev->data_offset;
return md_clear_badblocks(&rdev->badblocks,
- s + rdev->data_offset,
- sectors);
+ s, sectors);
}
EXPORT_SYMBOL_GPL(rdev_clear_badblocks);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index d51c0ca..98913e8 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -55,6 +55,7 @@ struct md_rdev {
int sb_loaded;
__u64 sb_events;
sector_t data_offset; /* start of data in array */
+ sector_t new_data_offset;/* only relevant while reshaping */
sector_t sb_start; /* offset of the super block (in 512byte sectors) */
int sb_size; /* bytes in the superblock */
int preferred_minor; /* autorun support */
@@ -193,8 +194,9 @@ static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
return 0;
}
extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
- int acknowledged);
-extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors);
+ int is_new);
+extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
+ int is_new);
extern void md_ack_all_badblocks(struct badblocks *bb);
struct mddev {
@@ -592,6 +594,7 @@ extern void md_write_start(struct mddev *mddev, struct bio *bi);
extern void md_write_end(struct mddev *mddev);
extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
+extern void md_finish_reshape(struct mddev *mddev);
extern int mddev_congested(struct mddev *mddev, int bits);
extern void md_flush_request(struct mddev *mddev, struct bio *bio);
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index d35e4c9..90bba78 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2023,7 +2023,7 @@ static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio
continue;
if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
test_bit(R1BIO_MadeGood, &r1_bio->state)) {
- rdev_clear_badblocks(rdev, r1_bio->sector, s);
+ rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
}
if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
test_bit(R1BIO_WriteError, &r1_bio->state)) {
@@ -2043,7 +2043,7 @@ static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
struct md_rdev *rdev = conf->mirrors[m].rdev;
rdev_clear_badblocks(rdev,
r1_bio->sector,
- r1_bio->sectors);
+ r1_bio->sectors, 0);
rdev_dec_pending(rdev, conf->mddev);
} else if (r1_bio->bios[m] != NULL) {
/* This drive got a write error. We need to
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index fff7821..b642841 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2480,7 +2480,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
- r10_bio->sectors);
+ r10_bio->sectors, 0);
} else {
if (!rdev_set_badblocks(
rdev,
@@ -2496,7 +2496,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
- r10_bio->sectors);
+ r10_bio->sectors, 0);
} else {
if (!rdev_set_badblocks(
rdev,
@@ -2515,7 +2515,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
- r10_bio->sectors);
+ r10_bio->sectors, 0);
rdev_dec_pending(rdev, conf->mddev);
} else if (bio != NULL &&
!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
@@ -2532,7 +2532,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
- r10_bio->sectors);
+ r10_bio->sectors, 0);
rdev_dec_pending(rdev, conf->mddev);
}
}
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 0abbd34..3705585 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3561,7 +3561,7 @@ finish:
if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
rdev = conf->disks[i].rdev;
rdev_clear_badblocks(rdev, sh->sector,
- STRIPE_SECTORS);
+ STRIPE_SECTORS, 0);
rdev_dec_pending(rdev, conf->mddev);
}
if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
@@ -3570,7 +3570,7 @@ finish:
/* rdev have been moved down */
rdev = conf->disks[i].rdev;
rdev_clear_badblocks(rdev, sh->sector,
- STRIPE_SECTORS);
+ STRIPE_SECTORS, 0);
rdev_dec_pending(rdev, conf->mddev);
}
}
@@ -5505,10 +5505,14 @@ static int raid5_start_reshape(struct mddev *mddev)
if (!check_stripe_cache(mddev))
return -ENOSPC;
- rdev_for_each(rdev, mddev)
+ rdev_for_each(rdev, mddev) {
+ /* Don't support changing data_offset yet */
+ if (rdev->new_data_offset != rdev->data_offset)
+ return -EINVAL;
if (!test_bit(In_sync, &rdev->flags)
&& !test_bit(Faulty, &rdev->flags))
spares++;
+ }
if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
/* Not enough devices even to make a degraded array
diff --git a/include/linux/raid/md_p.h b/include/linux/raid/md_p.h
index 07e05f9..ee75353 100644
--- a/include/linux/raid/md_p.h
+++ b/include/linux/raid/md_p.h
@@ -233,7 +233,10 @@ struct mdp_superblock_1 {
__le32 delta_disks; /* change in number of raid_disks */
__le32 new_layout; /* new layout */
__le32 new_chunk; /* new chunk size (512byte sectors) */
- __u8 pad1[128-124]; /* set to 0 when written */
+ __le32 new_offset; /* signed number to add to data_offset in new
+ * layout. 0 == no-change. This can be
+ * different on each device in the array.
+ */
/* constant this-device information - 64 bytes */
__le64 data_offset; /* sector start of data, often 0 */
@@ -285,11 +288,14 @@ struct mdp_superblock_1 {
* of devices, but is going
* backwards anyway.
*/
+#define MD_FEATURE_NEW_OFFSET 64 /* new_offset must be honoured */
#define MD_FEATURE_ALL (MD_FEATURE_BITMAP_OFFSET \
|MD_FEATURE_RECOVERY_OFFSET \
|MD_FEATURE_RESHAPE_ACTIVE \
|MD_FEATURE_BAD_BLOCKS \
|MD_FEATURE_REPLACEMENT \
- |MD_FEATURE_RESHAPE_BACKWARDS)
+ |MD_FEATURE_RESHAPE_BACKWARDS \
+ |MD_FEATURE_NEW_OFFSET \
+ )
#endif
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