On Wed, 22 Jul 2015 12:09:17 -0500 Goldwyn Rodrigues <rgoldwyn@xxxxxxxx> wrote: > 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 field in bitmap_info in bitmap_new_disk_sb > - ignore ->nodes for dm arrays (yes, this is a hack) > > References: https://bugzilla.kernel.org/show_bug.cgi?id=100491 > > Signed-off-By: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx> > --- > drivers/md/bitmap.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c > index f23b8e4..7ff37e0 100644 > --- a/drivers/md/bitmap.c > +++ b/drivers/md/bitmap.c > @@ -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)) Thanks for these. I've applied them all and marked this one for -stable ... it should stop the cluster code from being touched by mistake. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
