[PATCH] md: Checkpoint and allow restart of raid5 reshape
We allow the superblock to record an 'old' and a 'new' geometry, and a
position where any conversion is up to. The geometry allows for changing
chunksize, layout and level as well as number of devices.
When using verion-0.90 superblock, we convert the version to 0.91 while the
conversion is happening so that an old kernel will refuse the assemble the
array. For version-1, we use a feature bit for the same effect.
When starting an array we check for an incomplete reshape and restart the
reshape process if needed. If the reshape stopped at an awkward time (like
when updating the first stripe) we refuse to assemble the array, and let
user-space worry about it.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d169bc9..b9dfdfc 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -662,7 +662,8 @@
}
if (sb->major_version != 0 ||
- sb->minor_version != 90) {
+ sb->minor_version < 90 ||
+ sb->minor_version > 91) {
printk(KERN_WARNING "Bad version number %d.%d on %s\n",
sb->major_version, sb->minor_version,
b);
@@ -747,6 +748,20 @@
mddev->bitmap_offset = 0;
mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
+ if (mddev->minor_version >= 91) {
+ mddev->reshape_position = sb->reshape_position;
+ mddev->delta_disks = sb->delta_disks;
+ mddev->new_level = sb->new_level;
+ mddev->new_layout = sb->new_layout;
+ mddev->new_chunk = sb->new_chunk;
+ } else {
+ mddev->reshape_position = MaxSector;
+ mddev->delta_disks = 0;
+ mddev->new_level = mddev->level;
+ mddev->new_layout = mddev->layout;
+ mddev->new_chunk = mddev->chunk_size;
+ }
+
if (sb->state & (1<<MD_SB_CLEAN))
mddev->recovery_cp = MaxSector;
else {
@@ -841,7 +856,6 @@
sb->md_magic = MD_SB_MAGIC;
sb->major_version = mddev->major_version;
- sb->minor_version = mddev->minor_version;
sb->patch_version = mddev->patch_version;
sb->gvalid_words = 0; /* ignored */
memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
@@ -860,6 +874,17 @@
sb->events_hi = (mddev->events>>32);
sb->events_lo = (u32)mddev->events;
+ if (mddev->reshape_position == MaxSector)
+ sb->minor_version = 90;
+ else {
+ sb->minor_version = 91;
+ sb->reshape_position = mddev->reshape_position;
+ sb->new_level = mddev->new_level;
+ sb->delta_disks = mddev->delta_disks;
+ sb->new_layout = mddev->new_layout;
+ sb->new_chunk = mddev->new_chunk;
+ }
+ mddev->minor_version = sb->minor_version;
if (mddev->in_sync)
{
sb->recovery_cp = mddev->recovery_cp;
@@ -1104,6 +1129,20 @@
}
mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);
}
+ if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
+ mddev->reshape_position = le64_to_cpu(sb->reshape_position);
+ mddev->delta_disks = le32_to_cpu(sb->delta_disks);
+ mddev->new_level = le32_to_cpu(sb->new_level);
+ mddev->new_layout = le32_to_cpu(sb->new_layout);
+ mddev->new_chunk = le32_to_cpu(sb->new_chunk)<<9;
+ } else {
+ mddev->reshape_position = MaxSector;
+ mddev->delta_disks = 0;
+ mddev->new_level = mddev->level;
+ mddev->new_layout = mddev->layout;
+ mddev->new_chunk = mddev->chunk_size;
+ }
+
} else if (mddev->pers == NULL) {
/* Insist of good event counter while assembling */
__u64 ev1 = le64_to_cpu(sb->events);
@@ -1175,6 +1214,14 @@
sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
}
+ if (mddev->reshape_position != MaxSector) {
+ sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
+ sb->reshape_position = cpu_to_le64(mddev->reshape_position);
+ sb->new_layout = cpu_to_le32(mddev->new_layout);
+ sb->delta_disks = cpu_to_le32(mddev->delta_disks);
+ sb->new_level = cpu_to_le32(mddev->new_level);
+ sb->new_chunk = cpu_to_le32(mddev->new_chunk>>9);
+ }
max_dev = 0;
ITERATE_RDEV(mddev,rdev2,tmp)
@@ -1497,7 +1544,7 @@
}
}
-static void md_update_sb(mddev_t * mddev)
+void md_update_sb(mddev_t * mddev)
{
int err;
struct list_head *tmp;
@@ -1574,6 +1621,7 @@
wake_up(&mddev->sb_wait);
}
+EXPORT_SYMBOL_GPL(md_update_sb);
/* words written to sysfs files may, or my not, be \n terminated.
* We want to accept with case. For this we use cmd_match.
@@ -2545,6 +2593,14 @@
mddev->level = pers->level;
strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
+ if (mddev->reshape_position != MaxSector &&
+ pers->reshape == NULL) {
+ /* This personality cannot handle reshaping... */
+ mddev->pers = NULL;
+ module_put(pers->owner);
+ return -EINVAL;
+ }
+
mddev->recovery = 0;
mddev->resync_max_sectors = mddev->size << 1; /* may be over-ridden by personality */
mddev->barriers_work = 1;
@@ -3433,11 +3489,18 @@
mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
mddev->bitmap_offset = 0;
+ mddev->reshape_position = MaxSector;
+
/*
* Generate a 128 bit UUID
*/
get_random_bytes(mddev->uuid, 16);
+ mddev->new_level = mddev->level;
+ mddev->new_chunk = mddev->chunk_size;
+ mddev->new_layout = mddev->layout;
+ mddev->delta_disks = 0;
+
return 0;
}