From 490b54d6fb75f6ffd0471ec58bb38a992e2b40cd Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 3 Mar 2017 10:55:12 +0200 Subject: btrfs: convert extent_map.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 Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/extent_io.c') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 27fdb250b446..3649932e48d5 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2859,7 +2859,7 @@ __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset, em = *em_cached; if (extent_map_in_tree(em) && start >= em->start && start < extent_map_end(em)) { - atomic_inc(&em->refs); + refcount_inc(&em->refs); return em; } @@ -2870,7 +2870,7 @@ __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset, em = get_extent(BTRFS_I(inode), page, pg_offset, start, len, 0); if (em_cached && !IS_ERR_OR_NULL(em)) { BUG_ON(*em_cached); - atomic_inc(&em->refs); + refcount_inc(&em->refs); *em_cached = em; } return em; -- cgit v1.2.3