btrfs: get fs_info from block group in pin_down_extent

We can read fs_info from the block group cache structure and can drop it
from the parameters.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -6392,10 +6392,11 @@ static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
 	return bytenr;
 }
 
-static int pin_down_extent(struct btrfs_fs_info *fs_info,
-			   struct btrfs_block_group_cache *cache,
+static int pin_down_extent(struct btrfs_block_group_cache *cache,
 			   u64 bytenr, u64 num_bytes, int reserved)
 {
+	struct btrfs_fs_info *fs_info = cache->fs_info;
+
 	spin_lock(&cache->space_info->lock);
 	spin_lock(&cache->lock);
 	cache->pinned += num_bytes;
@@ -6427,7 +6428,7 @@ int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
 	cache = btrfs_lookup_block_group(fs_info, bytenr);
 	BUG_ON(!cache); /* Logic error */
 
-	pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
+	pin_down_extent(cache, bytenr, num_bytes, reserved);
 
 	btrfs_put_block_group(cache);
 	return 0;
@@ -6454,7 +6455,7 @@ int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
 	 */
 	cache_block_group(cache, 1);
 
-	pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
+	pin_down_extent(cache, bytenr, num_bytes, 0);
 
 	/* remove us from the free space cache (if we're there at all) */
 	ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
@@ -7206,8 +7207,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 		cache = btrfs_lookup_block_group(fs_info, buf->start);
 
 		if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
-			pin_down_extent(fs_info, cache, buf->start,
-					buf->len, 1);
+			pin_down_extent(cache, buf->start, buf->len, 1);
 			btrfs_put_block_group(cache);
 			goto out;
 		}
@@ -8182,7 +8182,7 @@ static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
 	}
 
 	if (pin)
-		pin_down_extent(fs_info, cache, start, len, 1);
+		pin_down_extent(cache, start, len, 1);
 	else {
 		if (btrfs_test_opt(fs_info, DISCARD))
 			ret = btrfs_discard_extent(fs_info, start, len, NULL);