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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.c
parent1e4f4714d59e3fdcde29ee12d40d2e96875a026f (diff)
downloadlinux-6df8cdf5bda221f268ac23940bce589ad176993d.tar.gz
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.c')
-rw-r--r--fs/btrfs/delayed-ref.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 6eb80952efb3..be70d90dfee5 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -164,7 +164,7 @@ int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 	if (mutex_trylock(&head->mutex))
 		return 0;
 
-	atomic_inc(&head->node.refs);
+	refcount_inc(&head->node.refs);
 	spin_unlock(&delayed_refs->lock);
 
 	mutex_lock(&head->mutex);
@@ -590,7 +590,7 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 	delayed_refs = &trans->transaction->delayed_refs;
 
 	/* first set the basic ref node struct up */
-	atomic_set(&ref->refs, 1);
+	refcount_set(&ref->refs, 1);
 	ref->bytenr = bytenr;
 	ref->num_bytes = num_bytes;
 	ref->ref_mod = count_mod;
@@ -682,7 +682,7 @@ add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 	delayed_refs = &trans->transaction->delayed_refs;
 
 	/* first set the basic ref node struct up */
-	atomic_set(&ref->refs, 1);
+	refcount_set(&ref->refs, 1);
 	ref->bytenr = bytenr;
 	ref->num_bytes = num_bytes;
 	ref->ref_mod = 1;
@@ -739,7 +739,7 @@ add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 		seq = atomic64_read(&fs_info->tree_mod_seq);
 
 	/* first set the basic ref node struct up */
-	atomic_set(&ref->refs, 1);
+	refcount_set(&ref->refs, 1);
 	ref->bytenr = bytenr;
 	ref->num_bytes = num_bytes;
 	ref->ref_mod = 1;