btrfs: convert btrfs_transaction.use_count 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 <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 9a46878ba60f..da5399f9fb54 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -623,7 +623,7 @@ void btrfs_remove_ordered_extent(struct inode *inode,
                 spin_lock(&fs_info->trans_lock);
                 trans = fs_info->running_transaction;
                 if (trans)
-                        atomic_inc(&trans->use_count);
+                        refcount_inc(&trans->use_count);
                 spin_unlock(&fs_info->trans_lock);
 
                 ASSERT(trans);