From 78a764504d1e11411bec0e068c5d9e0a417aff08 Mon Sep 17 00:00:00 2001
From: Elena Reshetova <elena.reshetova@intel.com>
Date: Fri, 3 Mar 2017 10:55:24 +0200
Subject: [PATCH] btrfs: convert scrub_parity.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>
---
fs/btrfs/scrub.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index d2c35848e61da..8130ab11821f3 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -142,7 +142,7 @@ struct scrub_parity {
int stripe_len;
- atomic_t refs;
+ refcount_t refs;
struct list_head spages;
@@ -2822,12 +2822,12 @@ static inline int scrub_calc_parity_bitmap_len(int nsectors)
static void scrub_parity_get(struct scrub_parity *sparity)
{
- atomic_inc(&sparity->refs);
+ refcount_inc(&sparity->refs);
}
static void scrub_parity_put(struct scrub_parity *sparity)
{
- if (!atomic_dec_and_test(&sparity->refs))
+ if (!refcount_dec_and_test(&sparity->refs))
return;
scrub_parity_check_and_repair(sparity);
@@ -2879,7 +2879,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
sparity->scrub_dev = sdev;
sparity->logic_start = logic_start;
sparity->logic_end = logic_end;
- atomic_set(&sparity->refs, 1);
+ refcount_set(&sparity->refs, 1);
INIT_LIST_HEAD(&sparity->spages);
sparity->dbitmap = sparity->bitmap;
sparity->ebitmap = (void *)sparity->bitmap + bitmap_len;
--
2.30.2