btrfs: convert btrfs_root.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 <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>
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 @@
*/
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);
}