From 089e77e10d7e44a007101cf7323dc7bda66172f4 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 3 Mar 2017 10:55:17 +0200 Subject: [PATCH] btrfs: convert btrfs_delayed_item.refs from atomic_t to refcount_t 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 Signed-off-by: David Sterba --- fs/btrfs/delayed-inode.c | 18 +++++++++--------- fs/btrfs/delayed-inode.h | 2 +- 2 files changed, 10 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 7396c36e0adb..8ae409b5a61d 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -308,7 +308,7 @@ static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u32 data_len) item->ins_or_del = 0; item->bytes_reserved = 0; item->delayed_node = NULL; - atomic_set(&item->refs, 1); + refcount_set(&item->refs, 1); } return item; } @@ -483,7 +483,7 @@ static void btrfs_release_delayed_item(struct btrfs_delayed_item *item) { if (item) { __btrfs_remove_delayed_item(item); - if (atomic_dec_and_test(&item->refs)) + if (refcount_dec_and_test(&item->refs)) kfree(item); } } @@ -1600,14 +1600,14 @@ bool btrfs_readdir_get_delayed_items(struct inode *inode, mutex_lock(&delayed_node->mutex); item = __btrfs_first_delayed_insertion_item(delayed_node); while (item) { - atomic_inc(&item->refs); + refcount_inc(&item->refs); list_add_tail(&item->readdir_list, ins_list); item = __btrfs_next_delayed_item(item); } item = __btrfs_first_delayed_deletion_item(delayed_node); while (item) { - atomic_inc(&item->refs); + refcount_inc(&item->refs); list_add_tail(&item->readdir_list, del_list); item = __btrfs_next_delayed_item(item); } @@ -1634,13 +1634,13 @@ void btrfs_readdir_put_delayed_items(struct inode *inode, list_for_each_entry_safe(curr, next, ins_list, readdir_list) { list_del(&curr->readdir_list); - if (atomic_dec_and_test(&curr->refs)) + if (refcount_dec_and_test(&curr->refs)) kfree(curr); } list_for_each_entry_safe(curr, next, del_list, readdir_list) { list_del(&curr->readdir_list); - if (atomic_dec_and_test(&curr->refs)) + if (refcount_dec_and_test(&curr->refs)) kfree(curr); } @@ -1667,7 +1667,7 @@ int btrfs_should_delete_dir_index(struct list_head *del_list, list_del(&curr->readdir_list); ret = (curr->key.offset == index); - if (atomic_dec_and_test(&curr->refs)) + if (refcount_dec_and_test(&curr->refs)) kfree(curr); if (ret) @@ -1705,7 +1705,7 @@ int btrfs_readdir_delayed_dir_index(struct dir_context *ctx, list_del(&curr->readdir_list); if (curr->key.offset < ctx->pos) { - if (atomic_dec_and_test(&curr->refs)) + if (refcount_dec_and_test(&curr->refs)) kfree(curr); continue; } @@ -1722,7 +1722,7 @@ int btrfs_readdir_delayed_dir_index(struct dir_context *ctx, over = !dir_emit(ctx, name, name_len, location.objectid, d_type); - if (atomic_dec_and_test(&curr->refs)) + if (refcount_dec_and_test(&curr->refs)) kfree(curr); if (over) diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h index 2f494fdde0ac..c4189d495934 100644 --- a/fs/btrfs/delayed-inode.h +++ b/fs/btrfs/delayed-inode.h @@ -80,7 +80,7 @@ struct btrfs_delayed_item { struct list_head readdir_list; /* used for readdir items */ u64 bytes_reserved; struct btrfs_delayed_node *delayed_node; - atomic_t refs; + refcount_t refs; int ins_or_del; u32 data_len; char data[0];