dm persistent data: tidy transaction manager creation fns

Tidy the transaction manager creation functions.

They no longer lock the superblock.  Superblock locking is pulled out to
the caller.

Also export dm_bm_write_lock_zero.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

4 files changed, 46 insertions, 55 deletions

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index c8f36227fd7b..4aadeae3af67 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -418,8 +418,7 @@ static int init_pmd(struct dm_pool_metadata *pmd,
         struct dm_block *sblock;
 
         if (create) {
-                r = dm_tm_create_with_sm(bm, THIN_SUPERBLOCK_LOCATION,
-                                         &sb_validator, &tm, &sm, &sblock);
+                r = dm_tm_create_with_sm(bm, THIN_SUPERBLOCK_LOCATION, &tm, &sm);
                 if (r < 0) {
                         DMERR("tm_create_with_sm failed");
                         return r;
@@ -428,38 +427,51 @@ static int init_pmd(struct dm_pool_metadata *pmd,
                 data_sm = dm_sm_disk_create(tm, nr_blocks);
                 if (IS_ERR(data_sm)) {
                         DMERR("sm_disk_create failed");
-                        dm_tm_unlock(tm, sblock);
                         r = PTR_ERR(data_sm);
                         goto bad;
                 }
+
+                /*
+                 * We cycle the superblock to let the validator do its stuff.
+                 */
+                r = dm_bm_write_lock_zero(bm, THIN_SUPERBLOCK_LOCATION, &sb_validator, &sblock);
+                if (r < 0) {
+                        DMERR("couldn't lock superblock");
+                        goto bad;
+                }
+
+                dm_bm_unlock(sblock);
+
         } else {
-                struct thin_disk_superblock *disk_super = NULL;
-                size_t space_map_root_offset =
-                        offsetof(struct thin_disk_superblock, metadata_space_map_root);
+                struct thin_disk_superblock *disk_super;
+
+                r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, &sb_validator, &sblock);
+                if (r < 0) {
+                        DMERR("couldn't read superblock");
+                        return r;
+                }
 
+                disk_super = dm_block_data(sblock);
                 r = dm_tm_open_with_sm(bm, THIN_SUPERBLOCK_LOCATION,
-                                       &sb_validator, space_map_root_offset,
-                                       SPACE_MAP_ROOT_SIZE, &tm, &sm, &sblock);
+                                       disk_super->metadata_space_map_root,
+                                       sizeof(disk_super->metadata_space_map_root),
+                                       &tm, &sm);
                 if (r < 0) {
                         DMERR("tm_open_with_sm failed");
+                        dm_bm_unlock(sblock);
                         return r;
                 }
 
-                disk_super = dm_block_data(sblock);
                 data_sm = dm_sm_disk_open(tm, disk_super->data_space_map_root,
                                           sizeof(disk_super->data_space_map_root));
                 if (IS_ERR(data_sm)) {
                         DMERR("sm_disk_open failed");
+                        dm_bm_unlock(sblock);
                         r = PTR_ERR(data_sm);
                         goto bad;
                 }
-        }
-
 
-        r = dm_tm_unlock(tm, sblock);
-        if (r < 0) {
-                DMERR("couldn't unlock superblock");
-                goto bad_data_sm;
+                dm_bm_unlock(sblock);
         }
 
         pmd->bm = bm;
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index c70ad6e303d3..4b5c504f47af 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -565,6 +565,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm,
 
         return 0;
 }
+EXPORT_SYMBOL_GPL(dm_bm_write_lock_zero);
 
 int dm_bm_unlock(struct dm_block *b)
 {
diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c
index 86c3705052a4..b4f05830af07 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.c
+++ b/drivers/md/persistent-data/dm-transaction-manager.c
@@ -310,12 +310,10 @@ struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm)
 
 static int dm_tm_create_internal(struct dm_block_manager *bm,
                                  dm_block_t sb_location,
-                                 struct dm_block_validator *sb_validator,
-                                 size_t root_offset, size_t root_max_len,
                                  struct dm_transaction_manager **tm,
                                  struct dm_space_map **sm,
-                                 struct dm_block **sblock,
-                                 int create)
+                                 int create,
+                                 void *sm_root, size_t sm_len)
 {
         int r;
 
@@ -330,64 +328,43 @@ static int dm_tm_create_internal(struct dm_block_manager *bm,
         }
 
         if (create) {
-                r = dm_bm_write_lock_zero(dm_tm_get_bm(*tm), sb_location,
-                                          sb_validator, sblock);
-                if (r < 0) {
-                        DMERR("couldn't lock superblock");
-                        goto bad1;
-                }
-
                 r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm),
                                           sb_location);
                 if (r) {
                         DMERR("couldn't create metadata space map");
-                        goto bad2;
+                        goto bad;
                 }
 
         } else {
-                r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location,
-                                     sb_validator, sblock);
-                if (r < 0) {
-                        DMERR("couldn't lock superblock");
-                        goto bad1;
-                }
-
-                r = dm_sm_metadata_open(*sm, *tm,
-                                        dm_block_data(*sblock) + root_offset,
-                                        root_max_len);
+                r = dm_sm_metadata_open(*sm, *tm, sm_root, sm_len);
                 if (r) {
                         DMERR("couldn't open metadata space map");
-                        goto bad2;
+                        goto bad;
                 }
         }
 
         return 0;
 
-bad2:
-        dm_tm_unlock(*tm, *sblock);
-bad1:
+bad:
         dm_tm_destroy(*tm);
+        dm_sm_destroy(*sm);
         return r;
 }
 
 int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-                         struct dm_block_validator *sb_validator,
                          struct dm_transaction_manager **tm,
-                         struct dm_space_map **sm, struct dm_block **sblock)
+                         struct dm_space_map **sm)
 {
-        return dm_tm_create_internal(bm, sb_location, sb_validator,
-                                     0, 0, tm, sm, sblock, 1);
+        return dm_tm_create_internal(bm, sb_location, tm, sm, 1, NULL, 0);
 }
 EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
 
 int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-                       struct dm_block_validator *sb_validator,
-                       size_t root_offset, size_t root_max_len,
+                       void *sm_root, size_t root_len,
                        struct dm_transaction_manager **tm,
-                       struct dm_space_map **sm, struct dm_block **sblock)
+                       struct dm_space_map **sm)
 {
-        return dm_tm_create_internal(bm, sb_location, sb_validator, root_offset,
-                                     root_max_len, tm, sm, sblock, 0);
+        return dm_tm_create_internal(bm, sb_location, tm, sm, 0, sm_root, root_len);
 }
 EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
 
diff --git a/drivers/md/persistent-data/dm-transaction-manager.h b/drivers/md/persistent-data/dm-transaction-manager.h
index 6da784871db4..b5b139076ca5 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.h
+++ b/drivers/md/persistent-data/dm-transaction-manager.h
@@ -115,16 +115,17 @@ struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm);
  *
  * Returns a tm that has an open transaction to write the new disk sm.
  * Caller should store the new sm root and commit.
+ *
+ * The superblock location is passed so the metadata space map knows it
+ * shouldn't be used.
  */
 int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-                         struct dm_block_validator *sb_validator,
                          struct dm_transaction_manager **tm,
-                         struct dm_space_map **sm, struct dm_block **sblock);
+                         struct dm_space_map **sm);
 
 int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-                       struct dm_block_validator *sb_validator,
-                       size_t root_offset, size_t root_max_len,
+                       void *sm_root, size_t root_len,
                        struct dm_transaction_manager **tm,
-                       struct dm_space_map **sm, struct dm_block **sblock);
+                       struct dm_space_map **sm);
 
 #endif  /* _LINUX_DM_TRANSACTION_MANAGER_H */