dm thin metadata: fix __udivdi3 undefined on 32-bit

[linux-2.6-microblaze.git] / drivers / md / dm-thin-metadata.c

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 7214202..20b0776 100644 (file)
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -188,6 +188,12 @@ struct dm_pool_metadata {
        unsigned long flags;
        sector_t data_block_size;
 
+       /*
+        * We reserve a section of the metadata for commit overhead.
+        * All reported space does *not* include this.
+        */
+       dm_block_t metadata_reserve;
+
        /*
         * Set if a transaction has to be aborted but the attempt to roll back
         * to the previous (good) transaction failed.  The only pool metadata
@@ -816,6 +822,20 @@ static int __commit_transaction(struct dm_pool_metadata *pmd)
        return dm_tm_commit(pmd->tm, sblock);
 }
 
+static void __set_metadata_reserve(struct dm_pool_metadata *pmd)
+{
+       int r;
+       dm_block_t total;
+       dm_block_t max_blocks = 4096; /* 16M */
+
+       r = dm_sm_get_nr_blocks(pmd->metadata_sm, &total);
+       if (r) {
+               DMERR("could not get size of metadata device");
+               pmd->metadata_reserve = max_blocks;
+       } else
+               pmd->metadata_reserve = min(max_blocks, div_u64(total, 10));
+}
+
 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
                                               sector_t data_block_size,
                                               bool format_device)
@@ -849,6 +869,8 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
                return ERR_PTR(r);
        }
 
+       __set_metadata_reserve(pmd);
+
        return pmd;
 }
 
@@ -1820,6 +1842,13 @@ int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
        down_read(&pmd->root_lock);
        if (!pmd->fail_io)
                r = dm_sm_get_nr_free(pmd->metadata_sm, result);
+
+       if (!r) {
+               if (*result < pmd->metadata_reserve)
+                       *result = 0;
+               else
+                       *result -= pmd->metadata_reserve;
+       }
        up_read(&pmd->root_lock);
 
        return r;
@@ -1932,8 +1961,11 @@ int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_cou
        int r = -EINVAL;
 
        down_write(&pmd->root_lock);
-       if (!pmd->fail_io)
+       if (!pmd->fail_io) {
                r = __resize_space_map(pmd->metadata_sm, new_count);
+               if (!r)
+                       __set_metadata_reserve(pmd);
+       }
        up_write(&pmd->root_lock);
 
        return r;