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authorElena Reshetova <elena.reshetova@intel.com>2017-03-03 10:55:15 +0200
committerDavid Sterba <dsterba@suse.com>2017-04-18 14:07:23 +0200
commit6df8cdf5bda221f268ac23940bce589ad176993d (patch)
treeecf4b8f44ace50682165d8812ccf75c7d802c87f /fs/btrfs/delayed-ref.h
parent1e4f4714d59e3fdcde29ee12d40d2e96875a026f (diff)
btrfs: convert btrfs_delayed_ref_node.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>
Diffstat (limited to 'fs/btrfs/delayed-ref.h')
-rw-r--r--fs/btrfs/delayed-ref.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 0e537f98f1a1..c0264ff01b53 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -18,6 +18,8 @@
#ifndef __DELAYED_REF__
#define __DELAYED_REF__
+#include <linux/refcount.h>
+
/* these are the possible values of struct btrfs_delayed_ref_node->action */
#define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */
#define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */
@@ -53,7 +55,7 @@ struct btrfs_delayed_ref_node {
u64 seq;
/* ref count on this data structure */
- atomic_t refs;
+ refcount_t refs;
/*
* how many refs is this entry adding or deleting. For
@@ -220,8 +222,8 @@ btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
{
- WARN_ON(atomic_read(&ref->refs) == 0);
- if (atomic_dec_and_test(&ref->refs)) {
+ WARN_ON(refcount_read(&ref->refs) == 0);
+ if (refcount_dec_and_test(&ref->refs)) {
WARN_ON(ref->in_tree);
switch (ref->type) {
case BTRFS_TREE_BLOCK_REF_KEY: