btrfs: account for pinned bytes in should_alloc_chunk

In a heavy write scenario, we can end up with a large number of pinned bytes.
This can translate into (very) premature ENOSPC because pinned bytes
must be accounted for when allowing a reservation but aren't accounted for
when deciding whether to create a new chunk.

This patch adds the accounting to should_alloc_chunk so that we can
create the chunk.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -4419,7 +4419,7 @@ static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
 {
 	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
 	u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
-	u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
+	u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned;
 	u64 thresh;
 
 	if (force == CHUNK_ALLOC_FORCE)