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Commit 7785a663 authored by Filipe Manana's avatar Filipe Manana
Browse files

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: default avatarFilipe Manana <fdmanana@suse.com>
parent 50460e37

fs/btrfs/transaction.c

+17 −0
Original line number Diff line number Diff line
@@ -75,6 +75,23 @@ void btrfs_put_transaction(struct btrfs_transaction *transaction) 
			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);

	}

}