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| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-03-03 10:55:15 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2017-04-18 14:07:23 +0200 |
| commit | 6df8cdf5bda221f268ac23940bce589ad176993d (patch) | |
| tree | ecf4b8f44ace50682165d8812ccf75c7d802c87f /fs/btrfs/delayed-ref.h | |
| parent | 1e4f4714d59e3fdcde29ee12d40d2e96875a026f (diff) | |
| download | lwn-6df8cdf5bda221f268ac23940bce589ad176993d.tar.gz lwn-6df8cdf5bda221f268ac23940bce589ad176993d.zip | |
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.h | 8 |
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: |