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md: Skip cluster setup for dm-raid 

There is a bug that the bitmap superblock isn't initialised properly for
dm-raid, so a new field can have garbage in new fields.
(dm-raid does initialisation in the kernel - md initialised the
 superblock in mdadm).

This means that for dm-raid we cannot currently trust the new ->nodes
field. So:
 - use __GFP_ZERO to initialise the superblock properly for all new
    arrays
 - initialise all fields in bitmap_info in bitmap_new_disk_sb
 - ignore ->nodes for dm arrays (yes, this is a hack)

This bug exposes dm-raid to bug in the (still experimental) md-cluster
code, so it is suitable for -stable.  It does cause crashes.

References: https://bugzilla.kernel.org/show_bug.cgi?id=100491
Cc: stable@vger.kernel.org (v4.1)
Signed-off-By: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>
This commit is contained in:
Goldwyn Rodrigues 2015-07-22 12:09:17 -05:00 committed by NeilBrown
parent ee5d004fd0
commit d3b178adb3
1 changed files with 12 additions and 3 deletions
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15
drivers/md/bitmap.c
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@ -494,7 +494,7 @@ static int bitmap_new_disk_sb(struct bitmap *bitmap)
bitmap_super_t *sb;
unsigned long chunksize, daemon_sleep, write_behind;
bitmap->storage.sb_page = alloc_page(GFP_KERNEL);
bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (bitmap->storage.sb_page == NULL)
return -ENOMEM;
bitmap->storage.sb_page->index = 0;
@ -541,6 +541,7 @@ static int bitmap_new_disk_sb(struct bitmap *bitmap)
sb->state = cpu_to_le32(bitmap->flags);
bitmap->events_cleared = bitmap->mddev->events;
sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
bitmap->mddev->bitmap_info.nodes = 0;
kunmap_atomic(sb);
@ -611,8 +612,16 @@ re_read:
daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
write_behind = le32_to_cpu(sb->write_behind);
sectors_reserved = le32_to_cpu(sb->sectors_reserved);
nodes = le32_to_cpu(sb->nodes);
strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
/* XXX: This is a hack to ensure that we don't use clustering
* in case:
* - dm-raid is in use and
* - the nodes written in bitmap_sb is erroneous.
*/
if (!bitmap->mddev->sync_super) {
nodes = le32_to_cpu(sb->nodes);
strlcpy(bitmap->mddev->bitmap_info.cluster_name,
sb->cluster_name, 64);
}
/* verify that the bitmap-specific fields are valid */
if (sb->magic != cpu_to_le32(BITMAP_MAGIC))