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

diff --git a/drivers/md/persistent-data/dm-btree-internal.h b/drivers/md/persistent-data/dm-btree-internal.h
index bf2b80d5c4707a64210b5e57deb785069dc7d921..8731b6ea026bd9b8cfbe2a21bbc06366e509181c 100644 (file)
--- a/drivers/md/persistent-data/dm-btree-internal.h
+++ b/drivers/md/persistent-data/dm-btree-internal.h
@@ -138,4 +138,10 @@ int lower_bound(struct btree_node *n, uint64_t key);
 
 extern struct dm_block_validator btree_node_validator;
 
+/*
+ * Value type for upper levels of multi-level btrees.
+ */
+extern void init_le64_type(struct dm_transaction_manager *tm,
+                          struct dm_btree_value_type *vt);
+
 #endif /* DM_BTREE_INTERNAL_H */

diff --git a/drivers/md/persistent-data/dm-btree-remove.c b/drivers/md/persistent-data/dm-btree-remove.c
index 9ca9eccd512fd99f8116a20ab1b3ed67d821cb6d..4222f774cf369b1eb1b031bd652854c573b224af 100644 (file)
--- a/drivers/md/persistent-data/dm-btree-remove.c
+++ b/drivers/md/persistent-data/dm-btree-remove.c
@@ -544,14 +544,6 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
        return r;
 }
 
-static struct dm_btree_value_type le64_type = {
-       .context = NULL,
-       .size = sizeof(__le64),
-       .inc = NULL,
-       .dec = NULL,
-       .equal = NULL
-};
-
 int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
                    uint64_t *keys, dm_block_t *new_root)
 {
@@ -559,12 +551,14 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
        int index = 0, r = 0;
        struct shadow_spine spine;
        struct btree_node *n;
+       struct dm_btree_value_type le64_vt;
 
+       init_le64_type(info->tm, &le64_vt);
        init_shadow_spine(&spine, info);
        for (level = 0; level < info->levels; level++) {
                r = remove_raw(&spine, info,
                               (level == last_level ?
-                               &info->value_type : &le64_type),
+                               &info->value_type : &le64_vt),
                               root, keys[level], (unsigned *)&index);
                if (r < 0)
                        break;
@@ -654,11 +648,13 @@ static int remove_one(struct dm_btree_info *info, dm_block_t root,
        int index = 0, r = 0;
        struct shadow_spine spine;
        struct btree_node *n;
+       struct dm_btree_value_type le64_vt;
        uint64_t k;
 
+       init_le64_type(info->tm, &le64_vt);
        init_shadow_spine(&spine, info);
        for (level = 0; level < last_level; level++) {
-               r = remove_raw(&spine, info, &le64_type,
+               r = remove_raw(&spine, info, &le64_vt,
                               root, keys[level], (unsigned *) &index);
                if (r < 0)
                        goto out;

diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c
index 1b5e13ec7f96a670ed7a9b5b472a5d2ee95a7dff..0dee514ba4c5f9e8d34d16e9d239ef333395c7d4 100644 (file)
--- 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;
+}

diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index fdd3793e22f957ef08db71f897607c68ce6eb6a3..c7726cebc4950c24cb6f6f2b7cacfa6465bddeb6 100644 (file)
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -667,12 +667,7 @@ static int insert(struct dm_btree_info *info, dm_block_t root,
        struct btree_node *n;
        struct dm_btree_value_type le64_type;
 
-       le64_type.context = NULL;
-       le64_type.size = sizeof(__le64);
-       le64_type.inc = NULL;
-       le64_type.dec = NULL;
-       le64_type.equal = NULL;
-
+       init_le64_type(info->tm, &le64_type);
        init_shadow_spine(&spine, info);
 
        for (level = 0; level < (info->levels - 1); level++) {