From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752188AbdCCJHm (ORCPT ); Fri, 3 Mar 2017 04:07:42 -0500 Received: from mga02.intel.com ([134.134.136.20]:4403 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752161AbdCCJHg (ORCPT ); Fri, 3 Mar 2017 04:07:36 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,236,1484035200"; d="scan'208";a="1137385064" From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, jbacik@fb.com, clm@fb.com, dsterba@suse.com, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 09/17] fs, btrfs: convert btrfs_root.refs from atomic_t to refcount_t Date: Fri, 3 Mar 2017 10:55:18 +0200 Message-Id: <1488531326-21271-10-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488531326-21271-1-git-send-email-elena.reshetova@intel.com> References: <1488531326-21271-1-git-send-email-elena.reshetova@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- fs/btrfs/ctree.h | 2 +- fs/btrfs/disk-io.c | 2 +- fs/btrfs/disk-io.h | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 557af39..c01bfca 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1221,7 +1221,7 @@ struct btrfs_root { dev_t anon_dev; spinlock_t root_item_lock; - atomic_t refs; + refcount_t refs; struct mutex delalloc_mutex; spinlock_t delalloc_lock; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 913df60..ca89ae3 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1340,7 +1340,7 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info, atomic_set(&root->log_writers, 0); atomic_set(&root->log_batch, 0); atomic_set(&root->orphan_inodes, 0); - atomic_set(&root->refs, 1); + refcount_set(&root->refs, 1); atomic_set(&root->will_be_snapshoted, 0); atomic_set(&root->qgroup_meta_rsv, 0); root->log_transid = 0; diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index 2e0ec29..21f1ceb 100644 --- a/fs/btrfs/disk-io.h +++ b/fs/btrfs/disk-io.h @@ -101,14 +101,14 @@ struct btrfs_root *btrfs_alloc_dummy_root(struct btrfs_fs_info *fs_info); */ static inline struct btrfs_root *btrfs_grab_fs_root(struct btrfs_root *root) { - if (atomic_inc_not_zero(&root->refs)) + if (refcount_inc_not_zero(&root->refs)) return root; return NULL; } static inline void btrfs_put_fs_root(struct btrfs_root *root) { - if (atomic_dec_and_test(&root->refs)) + if (refcount_dec_and_test(&root->refs)) kfree(root); } -- 2.7.4