Btrfs: fix memory leaks after transaction is aborted
When a transaction is aborted, or its commit fails before writing the new
superblock and calling btrfs_finish_extent_commit(), we leak reference
counts on the block groups attached to the transaction's delete_bgs list,
because btrfs_finish_extent_commit() is never called for those two cases.
Fix this by dropping their references at btrfs_put_transaction(), which
is called when transactions are aborted (by making the transaction kthread
commit the transaction) or if their commits fail.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index be8eae8..f85ccf6 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -75,6 +75,23 @@
list_del_init(&em->list);
free_extent_map(em);
}
+ /*
+ * If any block groups are found in ->deleted_bgs then it's
+ * because the transaction was aborted and a commit did not
+ * happen (things failed before writing the new superblock
+ * and calling btrfs_finish_extent_commit()), so we can not
+ * discard the physical locations of the block groups.
+ */
+ while (!list_empty(&transaction->deleted_bgs)) {
+ struct btrfs_block_group_cache *cache;
+
+ cache = list_first_entry(&transaction->deleted_bgs,
+ struct btrfs_block_group_cache,
+ bg_list);
+ list_del_init(&cache->bg_list);
+ btrfs_put_block_group_trimming(cache);
+ btrfs_put_block_group(cache);
+ }
kmem_cache_free(btrfs_transaction_cachep, transaction);
}
}