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| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-03-03 10:55:12 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2017-04-18 14:07:23 +0200 |
| commit | 490b54d6fb75f6ffd0471ec58bb38a992e2b40cd (patch) | |
| tree | a7f431ea6a0f4369ba43be8736090efd54d6998b /fs/btrfs/extent_map.c | |
| parent | 9b64f57ddf8673d29fafb3405d4aa1e93f5a4cd7 (diff) | |
| download | lwn-490b54d6fb75f6ffd0471ec58bb38a992e2b40cd.tar.gz lwn-490b54d6fb75f6ffd0471ec58bb38a992e2b40cd.zip | |
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 <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/extent_map.c')
| -rw-r--r-- | fs/btrfs/extent_map.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 26f9ac719d20..69850155870c 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -55,7 +55,7 @@ struct extent_map *alloc_extent_map(void) em->flags = 0; em->compress_type = BTRFS_COMPRESS_NONE; em->generation = 0; - atomic_set(&em->refs, 1); + refcount_set(&em->refs, 1); INIT_LIST_HEAD(&em->list); return em; } @@ -71,8 +71,8 @@ void free_extent_map(struct extent_map *em) { if (!em) return; - WARN_ON(atomic_read(&em->refs) == 0); - if (atomic_dec_and_test(&em->refs)) { + WARN_ON(refcount_read(&em->refs) == 0); + if (refcount_dec_and_test(&em->refs)) { WARN_ON(extent_map_in_tree(em)); WARN_ON(!list_empty(&em->list)); if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) @@ -322,7 +322,7 @@ static inline void setup_extent_mapping(struct extent_map_tree *tree, struct extent_map *em, int modified) { - atomic_inc(&em->refs); + refcount_inc(&em->refs); em->mod_start = em->start; em->mod_len = em->len; @@ -381,7 +381,7 @@ __lookup_extent_mapping(struct extent_map_tree *tree, if (strict && !(end > em->start && start < extent_map_end(em))) return NULL; - atomic_inc(&em->refs); + refcount_inc(&em->refs); return em; } |