btrfs: move the block group freeze/unfreeze helpers into block-group.c

The helpers btrfs_freeze_block_group() and btrfs_unfreeze_block_group()
used to be named btrfs_get_block_group_trimming() and
btrfs_put_block_group_trimming() respectively.

At the time they were added to free-space-cache.c, by commit e33e17e
("btrfs: add missing discards when unpinning extents with -o discard")
because all the trimming related functions were in free-space-cache.c.

Now that the helpers were renamed and are used in scrub context as well,
move them to block-group.c, a much more logical location for them.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/block-group.c

@@ -3381,3 +3381,44 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
 	}
 	return 0;
 }
+
+void btrfs_freeze_block_group(struct btrfs_block_group *cache)
+{
+	atomic_inc(&cache->frozen);
+}
+
+void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
+{
+	struct btrfs_fs_info *fs_info = block_group->fs_info;
+	struct extent_map_tree *em_tree;
+	struct extent_map *em;
+	bool cleanup;
+
+	spin_lock(&block_group->lock);
+	cleanup = (atomic_dec_and_test(&block_group->frozen) &&
+		   block_group->removed);
+	spin_unlock(&block_group->lock);
+
+	if (cleanup) {
+		mutex_lock(&fs_info->chunk_mutex);
+		em_tree = &fs_info->mapping_tree;
+		write_lock(&em_tree->lock);
+		em = lookup_extent_mapping(em_tree, block_group->start,
+					   1);
+		BUG_ON(!em); /* logic error, can't happen */
+		remove_extent_mapping(em_tree, em);
+		write_unlock(&em_tree->lock);
+		mutex_unlock(&fs_info->chunk_mutex);
+
+		/* once for us and once for the tree */
+		free_extent_map(em);
+		free_extent_map(em);
+
+		/*
+		 * We may have left one free space entry and other possible
+		 * tasks trimming this block group have left 1 entry each one.
+		 * Free them if any.
+		 */
+		__btrfs_remove_free_space_cache(block_group->free_space_ctl);
+	}
+}

fs/btrfs/block-group.h

@@ -292,6 +292,9 @@ static inline int btrfs_block_group_done(struct btrfs_block_group *cache)
 		cache->cached == BTRFS_CACHE_ERROR;
 }
 
+void btrfs_freeze_block_group(struct btrfs_block_group *cache);
+void btrfs_unfreeze_block_group(struct btrfs_block_group *cache);
+
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 		     u64 physical, u64 **logical, int *naddrs, int *stripe_len);

fs/btrfs/ctree.h

@@ -2481,8 +2481,6 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_ref *generic_ref);
 
 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr);
-void btrfs_freeze_block_group(struct btrfs_block_group *cache);
-void btrfs_unfreeze_block_group(struct btrfs_block_group *cache);
 void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
 
 enum btrfs_reserve_flush_enum {

fs/btrfs/free-space-cache.c

@@ -3762,47 +3762,6 @@ static int trim_bitmaps(struct btrfs_block_group *block_group,
 	return ret;
 }
 
-void btrfs_freeze_block_group(struct btrfs_block_group *cache)
-{
-	atomic_inc(&cache->frozen);
-}
-
-void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
-{
-	struct btrfs_fs_info *fs_info = block_group->fs_info;
-	struct extent_map_tree *em_tree;
-	struct extent_map *em;
-	bool cleanup;
-
-	spin_lock(&block_group->lock);
-	cleanup = (atomic_dec_and_test(&block_group->frozen) &&
-		   block_group->removed);
-	spin_unlock(&block_group->lock);
-
-	if (cleanup) {
-		mutex_lock(&fs_info->chunk_mutex);
-		em_tree = &fs_info->mapping_tree;
-		write_lock(&em_tree->lock);
-		em = lookup_extent_mapping(em_tree, block_group->start,
-					   1);
-		BUG_ON(!em); /* logic error, can't happen */
-		remove_extent_mapping(em_tree, em);
-		write_unlock(&em_tree->lock);
-		mutex_unlock(&fs_info->chunk_mutex);
-
-		/* once for us and once for the tree */
-		free_extent_map(em);
-		free_extent_map(em);
-
-		/*
-		 * We may have left one free space entry and other possible
-		 * tasks trimming this block group have left 1 entry each one.
-		 * Free them if any.
-		 */
-		__btrfs_remove_free_space_cache(block_group->free_space_ctl);
-	}
-}
-
 int btrfs_trim_block_group(struct btrfs_block_group *block_group,
 			   u64 *trimmed, u64 start, u64 end, u64 minlen)
 {