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Commit 01eacb27 authored by Filipe Manana's avatar Filipe Manana Committed by Chris Mason
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Btrfs: always clear a block group node when removing it from the tree 



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: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent a1e7e16e

fs/btrfs/extent-tree.c

+3 −0
Original line number Diff line number Diff line
@@ -8872,6 +8872,7 @@ 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);
@@ -9130,6 +9131,7 @@ 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;
@@ -9271,6 +9273,7 @@ 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;