This is a note to let you know that I've just added the patch titled
md: Skip cluster setup for dm-raid
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-skip-cluster-setup-for-dm-raid.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d3b178adb3a3adf54ecf77758138b654c3ee7f09 Mon Sep 17 00:00:00 2001
From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Date: Wed, 22 Jul 2015 12:09:17 -0500
Subject: md: Skip cluster setup for dm-raid
From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
commit d3b178adb3a3adf54ecf77758138b654c3ee7f09 upstream.
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
Signed-off-By: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/bitmap.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -494,7 +494,7 @@ static int bitmap_new_disk_sb(struct bit
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 bit
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))
Patches currently in stable-queue which might be from rgoldwyn@xxxxxxxx are
queue-4.1/md-skip-cluster-setup-for-dm-raid.patch
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