Merge tag 'dm-3.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm

Pull device-mapper fixes from Alasdair G Kergon:
 "Fix reported data loss with discards and thin snapshots; avoid a
  deadlock observed in dm verity; fix a race in the new dm cache code
  along with some other minor bugs; store the cache policy version on
  disk to make the stored hints format future-proof."

* tag 'dm-3.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
  dm cache: policy ignore hints if generated by different version
  dm cache: policy change version from string to integer set
  dm cache: fix race in writethrough implementation
  dm cache: metadata clear dirty bits on clean shutdown
  dm cache: avoid calling policy destructor twice on error
  dm cache: detect cache_create failure
  dm cache: avoid 64 bit division on 32 bit
  dm verity: avoid deadlock
  dm thin: fix non power of two discard granularity calc
  dm thin: fix discard corruption

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/md/dm-cache-policy.c b/drivers/md/dm-cache-policy.c
index 2cbf5fdaac5..21c03c570c0 100644
--- a/drivers/md/dm-cache-policy.c
+++ b/drivers/md/dm-cache-policy.c
@@ -150,6 +150,14 @@ const char *dm_cache_policy_get_name(struct dm_cache_policy *p)
 }
 EXPORT_SYMBOL_GPL(dm_cache_policy_get_name);
 
+const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p)
+{
+	struct dm_cache_policy_type *t = p->private;
+
+	return t->version;
+}
+EXPORT_SYMBOL_GPL(dm_cache_policy_get_version);
+
 size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p)
 {
 	struct dm_cache_policy_type *t = p->private;