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authorJoe Thornber <ejt@redhat.com>2015-08-12 15:12:09 +0100
committerMike Snitzer <snitzer@redhat.com>2015-08-12 10:50:37 -0400
commitb0dc3c8bc157c60b1d470163882be8c13e1950af (patch)
treecce26617905afa50fd19066971f215baa4a19ca3 /drivers/md/persistent-data/dm-btree-spine.c
parent7f518ad0a212e2a6fd68630e176af1de395070a7 (diff)
dm btree: add ref counting ops for the leaves of top level btrees
When using nested btrees, the top leaves of the top levels contain block addresses for the root of the next tree down. If we shadow a shared leaf node the leaf values (sub tree roots) should be incremented accordingly. This is only an issue if there is metadata sharing in the top levels. Which only occurs if metadata snapshots are being used (as is possible with dm-thinp). And could result in a block from the thinp metadata snap being reused early, thus corrupting the thinp metadata snap. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/md/persistent-data/dm-btree-spine.c')
-rw-r--r--drivers/md/persistent-data/dm-btree-spine.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c
index 1b5e13ec7f96..0dee514ba4c5 100644
--- a/drivers/md/persistent-data/dm-btree-spine.c
+++ b/drivers/md/persistent-data/dm-btree-spine.c
@@ -249,3 +249,40 @@ int shadow_root(struct shadow_spine *s)
{
return s->root;
}
+
+static void le64_inc(void *context, const void *value_le)
+{
+ struct dm_transaction_manager *tm = context;
+ __le64 v_le;
+
+ memcpy(&v_le, value_le, sizeof(v_le));
+ dm_tm_inc(tm, le64_to_cpu(v_le));
+}
+
+static void le64_dec(void *context, const void *value_le)
+{
+ struct dm_transaction_manager *tm = context;
+ __le64 v_le;
+
+ memcpy(&v_le, value_le, sizeof(v_le));
+ dm_tm_dec(tm, le64_to_cpu(v_le));
+}
+
+static int le64_equal(void *context, const void *value1_le, const void *value2_le)
+{
+ __le64 v1_le, v2_le;
+
+ memcpy(&v1_le, value1_le, sizeof(v1_le));
+ memcpy(&v2_le, value2_le, sizeof(v2_le));
+ return v1_le == v2_le;
+}
+
+void init_le64_type(struct dm_transaction_manager *tm,
+ struct dm_btree_value_type *vt)
+{
+ vt->context = tm;
+ vt->size = sizeof(__le64);
+ vt->inc = le64_inc;
+ vt->dec = le64_dec;
+ vt->equal = le64_equal;
+}