dm thin metadata: introduce THIN_MAX_CONCURRENT_LOCKS

[pandora-kernel.git] / drivers / md / dm-thin-metadata.c

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 59c4f04..525f560 100644 (file)
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -80,6 +80,12 @@
 #define THIN_METADATA_CACHE_SIZE 64
 #define SECTOR_TO_BLOCK_SHIFT 3
 
+/*
+ *  3 for btree insert +
+ *  2 for btree lookup used within space map
+ */
+#define THIN_MAX_CONCURRENT_LOCKS 5
+
 /* This should be plenty */
 #define SPACE_MAP_ROOT_SIZE 128
 
@@ -385,6 +391,7 @@ 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;
                }
@@ -668,13 +675,9 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
                return ERR_PTR(-ENOMEM);
        }
 
-       /*
-        * Max hex locks:
-        *  3 for btree insert +
-        *  2 for btree lookup used within space map
-        */
        bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE,
-                                    THIN_METADATA_CACHE_SIZE, 5);
+                                    THIN_METADATA_CACHE_SIZE,
+                                    THIN_MAX_CONCURRENT_LOCKS);
        if (!bm) {
                DMERR("could not create block manager");
                kfree(pmd);
@@ -789,6 +792,11 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
        return 0;
 }
 
+/*
+ * __open_device: Returns @td corresponding to device with id @dev,
+ * creating it if @create is set and incrementing @td->open_count.
+ * On failure, @td is undefined.
+ */
 static int __open_device(struct dm_pool_metadata *pmd,
                         dm_thin_id dev, int create,
                         struct dm_thin_device **td)
@@ -799,10 +807,16 @@ static int __open_device(struct dm_pool_metadata *pmd,
        struct disk_device_details details_le;
 
        /*
-        * Check the device isn't already open.
+        * If the device is already open, return it.
         */
        list_for_each_entry(td2, &pmd->thin_devices, list)
                if (td2->id == dev) {
+                       /*
+                        * May not create an already-open device.
+                        */
+                       if (create)
+                               return -EEXIST;
+
                        td2->open_count++;
                        *td = td2;
                        return 0;
@@ -817,6 +831,9 @@ static int __open_device(struct dm_pool_metadata *pmd,
                if (r != -ENODATA || !create)
                        return r;
 
+               /*
+                * Create new device.
+                */
                changed = 1;
                details_le.mapped_blocks = 0;
                details_le.transaction_id = cpu_to_le64(pmd->trans_id);
@@ -882,12 +899,10 @@ static int __create_thin(struct dm_pool_metadata *pmd,
 
        r = __open_device(pmd, dev, 1, &td);
        if (r) {
-               __close_device(td);
                dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
                dm_btree_del(&pmd->bl_info, dev_root);
                return r;
        }
-       td->changed = 1;
        __close_device(td);
 
        return r;
@@ -967,14 +982,14 @@ static int __create_snap(struct dm_pool_metadata *pmd,
                goto bad;
 
        r = __set_snapshot_details(pmd, td, origin, pmd->time);
+       __close_device(td);
+
        if (r)
                goto bad;
 
-       __close_device(td);
        return 0;
 
 bad:
-       __close_device(td);
        dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
        dm_btree_remove(&pmd->details_info, pmd->details_root,
                        &key, &pmd->details_root);
@@ -1211,6 +1226,8 @@ static int __remove(struct dm_thin_device *td, dm_block_t block)
        if (r)
                return r;
 
+       td->mapped_blocks--;
+       td->changed = 1;
        pmd->need_commit = 1;
 
        return 0;