Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

[uclinux-h8/linux.git] / fs / btrfs / extent-tree.c

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 171312d..07204bf 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4227,6 +4227,24 @@ out:
        space_info->chunk_alloc = 0;
        spin_unlock(&space_info->lock);
        mutex_unlock(&fs_info->chunk_mutex);
+       /*
+        * When we allocate a new chunk we reserve space in the chunk block
+        * reserve to make sure we can COW nodes/leafs in the chunk tree or
+        * add new nodes/leafs to it if we end up needing to do it when
+        * inserting the chunk item and updating device items as part of the
+        * second phase of chunk allocation, performed by
+        * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
+        * large number of new block groups to create in our transaction
+        * handle's new_bgs list to avoid exhausting the chunk block reserve
+        * in extreme cases - like having a single transaction create many new
+        * block groups when starting to write out the free space caches of all
+        * the block groups that were made dirty during the lifetime of the
+        * transaction.
+        */
+       if (trans->chunk_bytes_reserved >= (2 * 1024 * 1024ull)) {
+               btrfs_create_pending_block_groups(trans, trans->root);
+               btrfs_trans_release_chunk_metadata(trans);
+       }
        return ret;
 }