dm space map common: make sure new space is used during extend

When extending a low level space map we should update nr_blocks at
the start so the new space is used for the index entries.

Otherwise extend can fail, e.g.: sm_metadata_extend call sequence
that fails:
 -> sm_ll_extend
    -> dm_tm_new_block -> dm_sm_new_block -> sm_bootstrap_new_block
    => returns -ENOSPC because smm->begin == smm->ll.nr_blocks

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c
index 466a60bbd716..aacbe70c2c2e 100644
--- a/drivers/md/persistent-data/dm-space-map-common.c
+++ b/drivers/md/persistent-data/dm-space-map-common.c
@@ -245,6 +245,10 @@ int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
                 return -EINVAL;
         }
 
+        /*
+         * We need to set this before the dm_tm_new_block() call below.
+         */
+        ll->nr_blocks = nr_blocks;
         for (i = old_blocks; i < blocks; i++) {
                 struct dm_block *b;
                 struct disk_index_entry idx;
@@ -252,6 +256,7 @@ int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
                 r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b);
                 if (r < 0)
                         return r;
+
                 idx.blocknr = cpu_to_le64(dm_block_location(b));
 
                 r = dm_tm_unlock(ll->tm, b);
@@ -266,7 +271,6 @@ int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
                         return r;
         }
 
-        ll->nr_blocks = nr_blocks;
         return 0;
 }