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>

1 files changed, 27 insertions, 15 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;