Commit ff1f2b44 authored Jul 27, 2011 by liubo Committed by Chris Mason Aug 01, 2011

Btrfs: fix oops while writing data to SSD partitions



Here I have a two SSD-partitions btrfs, and they are defaultly set to
"data=raid0, metadata=raid1", then I try to fill my btrfs partition
till "No space left on device", via "dd if=/dev/zero of=/mnt/btrfs/tmp".

I get an oops panic from kernel BUG at fs/btrfs/extent-tree.c:5199!, which
refers to find_free_extent's
BUG_ON(index != get_block_group_index(block_group));

In SSD mode, in order to find enough space to alloc, we may check the
block_group cache which has been checked sometime before, but the index is not
updated, where it hits the BUG_ON.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Acked-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

parent 61cfea9b

fs/btrfs/extent-tree.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -5079,7 +5079,9 @@ have_block_group:
		* group is does point to and try again
		*/
		if (!last_ptr_loop && last_ptr->block_group &&
		last_ptr->block_group != block_group) {
		last_ptr->block_group != block_group &&
		index <=
		get_block_group_index(last_ptr->block_group)) {

		btrfs_put_block_group(block_group);
		block_group = last_ptr->block_group;