Always clear a block group's rbnode after removing it from the rbtree to
ensure that any tasks that might be holding a reference on the block group
don't end up accessing stale rbnode left and right child pointers through
next_block_group().
This is a leftover from the change titled:
"Btrfs: fix invalid block group rbtree access after bg is removed"
Signed-off-by: Filipe Manana <fdman...@suse.com>
---
fs/btrfs/extent-tree.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a7b81b4..c2fc261 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -8886,6 +8886,7 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
cache_node);
rb_erase(&block_group->cache_node,
&info->block_group_cache_tree);
+ RB_CLEAR_NODE(&block_group->cache_node);
spin_unlock(&info->block_group_cache_lock);
down_write(&block_group->space_info->groups_sem);
@@ -9143,6 +9144,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
spin_lock(&info->block_group_cache_lock);
rb_erase(&cache->cache_node,
&info->block_group_cache_tree);
+ RB_CLEAR_NODE(&cache->cache_node);
spin_unlock(&info->block_group_cache_lock);
btrfs_put_block_group(cache);
goto error;
@@ -9284,6 +9286,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle
*trans,
spin_lock(&root->fs_info->block_group_cache_lock);
rb_erase(&cache->cache_node,
&root->fs_info->block_group_cache_tree);
+ RB_CLEAR_NODE(&cache->cache_node);
spin_unlock(&root->fs_info->block_group_cache_lock);
btrfs_put_block_group(cache);
return ret;
--
2.1.3
--
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