btrfs: free mapping node on duplicate reloc root insert

__add_reloc_root() allocates a mapping_node before inserting it into
rc->reloc_root_tree.  If rb_simple_insert() finds an existing entry, it
returns the existing rb_node and leaves the newly allocated node unlinked.

The error path then returns -EEXIST without freeing the new node.  Since
the node was never inserted into reloc_root_tree, the later cleanup in
put_reloc_control() cannot find it either.

Free the newly allocated node before returning -EEXIST.

The callers currently assert that -EEXIST should not happen, so this is a
defensive cleanup for an unexpected duplicate insert path.  If the path is
ever reached, the local allocation should still be released.

Fixes: 57a304cfd43b ("btrfs: do not panic in __add_reloc_root")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Guanghui Yang <3497809730@qq.com>
Signed-off-by: David Sterba <dsterba@suse.com>

0 files changed, 0 insertions, 0 deletions