diff options
| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-03-03 10:55:14 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2017-04-18 14:07:23 +0200 |
| commit | 1e4f4714d59e3fdcde29ee12d40d2e96875a026f (patch) | |
| tree | 1298d39f3b3dae00776bc15a1f6677b0bb32dfaf /fs | |
| parent | e76edab7f059bc1047c1865141e2709d70e74852 (diff) | |
btrfs: convert btrfs_caching_control.count 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')
| -rw-r--r-- | fs/btrfs/ctree.h | 3 | ||||
| -rw-r--r-- | fs/btrfs/extent-tree.c | 12 |
2 files changed, 8 insertions, 7 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index c4115901d906..cdfc2a46448b 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -39,6 +39,7 @@ #include <linux/security.h> #include <linux/sizes.h> #include <linux/dynamic_debug.h> +#include <linux/refcount.h> #include "extent_io.h" #include "extent_map.h" #include "async-thread.h" @@ -518,7 +519,7 @@ struct btrfs_caching_control { struct btrfs_work work; struct btrfs_block_group_cache *block_group; u64 progress; - atomic_t count; + refcount_t count; }; /* Once caching_thread() finds this much free space, it will wake up waiters. */ diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 85e51f311b57..5c84eea60703 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -316,14 +316,14 @@ get_caching_control(struct btrfs_block_group_cache *cache) } ctl = cache->caching_ctl; - atomic_inc(&ctl->count); + refcount_inc(&ctl->count); spin_unlock(&cache->lock); return ctl; } static void put_caching_control(struct btrfs_caching_control *ctl) { - if (atomic_dec_and_test(&ctl->count)) + if (refcount_dec_and_test(&ctl->count)) kfree(ctl); } @@ -599,7 +599,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache, init_waitqueue_head(&caching_ctl->wait); caching_ctl->block_group = cache; caching_ctl->progress = cache->key.objectid; - atomic_set(&caching_ctl->count, 1); + refcount_set(&caching_ctl->count, 1); btrfs_init_work(&caching_ctl->work, btrfs_cache_helper, caching_thread, NULL, NULL); @@ -620,7 +620,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache, struct btrfs_caching_control *ctl; ctl = cache->caching_ctl; - atomic_inc(&ctl->count); + refcount_inc(&ctl->count); prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE); spin_unlock(&cache->lock); @@ -707,7 +707,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache, } down_write(&fs_info->commit_root_sem); - atomic_inc(&caching_ctl->count); + refcount_inc(&caching_ctl->count); list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups); up_write(&fs_info->commit_root_sem); @@ -10416,7 +10416,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, &fs_info->caching_block_groups, list) if (ctl->block_group == block_group) { caching_ctl = ctl; - atomic_inc(&caching_ctl->count); + refcount_inc(&caching_ctl->count); break; } } |