btrfs: migrate the block group cleanup code

This can now be easily migrated as well.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ refresh on top of sysfs cleanups ]
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/block-group.c

@@ -3045,3 +3045,130 @@ void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
 	}
 }
 
+void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
+{
+	struct btrfs_block_group_cache *block_group;
+	u64 last = 0;
+
+	while (1) {
+		struct inode *inode;
+
+		block_group = btrfs_lookup_first_block_group(info, last);
+		while (block_group) {
+			btrfs_wait_block_group_cache_done(block_group);
+			spin_lock(&block_group->lock);
+			if (block_group->iref)
+				break;
+			spin_unlock(&block_group->lock);
+			block_group = btrfs_next_block_group(block_group);
+		}
+		if (!block_group) {
+			if (last == 0)
+				break;
+			last = 0;
+			continue;
+		}
+
+		inode = block_group->inode;
+		block_group->iref = 0;
+		block_group->inode = NULL;
+		spin_unlock(&block_group->lock);
+		ASSERT(block_group->io_ctl.inode == NULL);
+		iput(inode);
+		last = block_group->key.objectid + block_group->key.offset;
+		btrfs_put_block_group(block_group);
+	}
+}
+
+/*
+ * Must be called only after stopping all workers, since we could have block
+ * group caching kthreads running, and therefore they could race with us if we
+ * freed the block groups before stopping them.
+ */
+int btrfs_free_block_groups(struct btrfs_fs_info *info)
+{
+	struct btrfs_block_group_cache *block_group;
+	struct btrfs_space_info *space_info;
+	struct btrfs_caching_control *caching_ctl;
+	struct rb_node *n;
+
+	down_write(&info->commit_root_sem);
+	while (!list_empty(&info->caching_block_groups)) {
+		caching_ctl = list_entry(info->caching_block_groups.next,
+					 struct btrfs_caching_control, list);
+		list_del(&caching_ctl->list);
+		btrfs_put_caching_control(caching_ctl);
+	}
+	up_write(&info->commit_root_sem);
+
+	spin_lock(&info->unused_bgs_lock);
+	while (!list_empty(&info->unused_bgs)) {
+		block_group = list_first_entry(&info->unused_bgs,
+					       struct btrfs_block_group_cache,
+					       bg_list);
+		list_del_init(&block_group->bg_list);
+		btrfs_put_block_group(block_group);
+	}
+	spin_unlock(&info->unused_bgs_lock);
+
+	spin_lock(&info->block_group_cache_lock);
+	while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
+		block_group = rb_entry(n, struct btrfs_block_group_cache,
+				       cache_node);
+		rb_erase(&block_group->cache_node,
+			 &info->block_group_cache_tree);
+		RB_CLEAR_NODE(&block_group->cache_node);
+		spin_unlock(&info->block_group_cache_lock);
+
+		down_write(&block_group->space_info->groups_sem);
+		list_del(&block_group->list);
+		up_write(&block_group->space_info->groups_sem);
+
+		/*
+		 * We haven't cached this block group, which means we could
+		 * possibly have excluded extents on this block group.
+		 */
+		if (block_group->cached == BTRFS_CACHE_NO ||
+		    block_group->cached == BTRFS_CACHE_ERROR)
+			btrfs_free_excluded_extents(block_group);
+
+		btrfs_remove_free_space_cache(block_group);
+		ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
+		ASSERT(list_empty(&block_group->dirty_list));
+		ASSERT(list_empty(&block_group->io_list));
+		ASSERT(list_empty(&block_group->bg_list));
+		ASSERT(atomic_read(&block_group->count) == 1);
+		btrfs_put_block_group(block_group);
+
+		spin_lock(&info->block_group_cache_lock);
+	}
+	spin_unlock(&info->block_group_cache_lock);
+
+	/*
+	 * Now that all the block groups are freed, go through and free all the
+	 * space_info structs.  This is only called during the final stages of
+	 * unmount, and so we know nobody is using them.  We call
+	 * synchronize_rcu() once before we start, just to be on the safe side.
+	 */
+	synchronize_rcu();
+
+	btrfs_release_global_block_rsv(info);
+
+	while (!list_empty(&info->space_info)) {
+		space_info = list_entry(info->space_info.next,
+					struct btrfs_space_info,
+					list);
+
+		/*
+		 * Do not hide this behind enospc_debug, this is actually
+		 * important and indicates a real bug if this happens.
+		 */
+		if (WARN_ON(space_info->bytes_pinned > 0 ||
+			    space_info->bytes_reserved > 0 ||
+			    space_info->bytes_may_use > 0))
+			btrfs_dump_space_info(info, space_info, 0, 0);
+		list_del(&space_info->list);
+		btrfs_sysfs_remove_space_info(space_info);
+	}
+	return 0;
+}

fs/btrfs/block-group.h

@@ -220,6 +220,8 @@ int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type);
 void check_system_chunk(struct btrfs_trans_handle *trans, const u64 type);
 u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags);
+void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
+int btrfs_free_block_groups(struct btrfs_fs_info *info);
 
 static inline u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
 {

fs/btrfs/ctree.h

@@ -2524,7 +2524,6 @@ 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);
-int btrfs_free_block_groups(struct btrfs_fs_info *info);
 void btrfs_get_block_group_trimming(struct btrfs_block_group_cache *cache);
 void btrfs_put_block_group_trimming(struct btrfs_block_group_cache *cache);
 void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
@@ -2561,7 +2560,6 @@ void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes,
 				    bool qgroup_free);
 
 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes);
-void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo);
 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
 				   u64 start, u64 end);

fs/btrfs/extent-tree.c

@@ -5515,134 +5515,6 @@ u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
 	return free_bytes;
 }
 
-void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
-{
-	struct btrfs_block_group_cache *block_group;
-	u64 last = 0;
-
-	while (1) {
-		struct inode *inode;
-
-		block_group = btrfs_lookup_first_block_group(info, last);
-		while (block_group) {
-			btrfs_wait_block_group_cache_done(block_group);
-			spin_lock(&block_group->lock);
-			if (block_group->iref)
-				break;
-			spin_unlock(&block_group->lock);
-			block_group = btrfs_next_block_group(block_group);
-		}
-		if (!block_group) {
-			if (last == 0)
-				break;
-			last = 0;
-			continue;
-		}
-
-		inode = block_group->inode;
-		block_group->iref = 0;
-		block_group->inode = NULL;
-		spin_unlock(&block_group->lock);
-		ASSERT(block_group->io_ctl.inode == NULL);
-		iput(inode);
-		last = block_group->key.objectid + block_group->key.offset;
-		btrfs_put_block_group(block_group);
-	}
-}
-
-/*
- * Must be called only after stopping all workers, since we could have block
- * group caching kthreads running, and therefore they could race with us if we
- * freed the block groups before stopping them.
- */
-int btrfs_free_block_groups(struct btrfs_fs_info *info)
-{
-	struct btrfs_block_group_cache *block_group;
-	struct btrfs_space_info *space_info;
-	struct btrfs_caching_control *caching_ctl;
-	struct rb_node *n;
-
-	down_write(&info->commit_root_sem);
-	while (!list_empty(&info->caching_block_groups)) {
-		caching_ctl = list_entry(info->caching_block_groups.next,
-					 struct btrfs_caching_control, list);
-		list_del(&caching_ctl->list);
-		btrfs_put_caching_control(caching_ctl);
-	}
-	up_write(&info->commit_root_sem);
-
-	spin_lock(&info->unused_bgs_lock);
-	while (!list_empty(&info->unused_bgs)) {
-		block_group = list_first_entry(&info->unused_bgs,
-					       struct btrfs_block_group_cache,
-					       bg_list);
-		list_del_init(&block_group->bg_list);
-		btrfs_put_block_group(block_group);
-	}
-	spin_unlock(&info->unused_bgs_lock);
-
-	spin_lock(&info->block_group_cache_lock);
-	while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
-		block_group = rb_entry(n, struct btrfs_block_group_cache,
-				       cache_node);
-		rb_erase(&block_group->cache_node,
-			 &info->block_group_cache_tree);
-		RB_CLEAR_NODE(&block_group->cache_node);
-		spin_unlock(&info->block_group_cache_lock);
-
-		down_write(&block_group->space_info->groups_sem);
-		list_del(&block_group->list);
-		up_write(&block_group->space_info->groups_sem);
-
-		/*
-		 * We haven't cached this block group, which means we could
-		 * possibly have excluded extents on this block group.
-		 */
-		if (block_group->cached == BTRFS_CACHE_NO ||
-		    block_group->cached == BTRFS_CACHE_ERROR)
-			btrfs_free_excluded_extents(block_group);
-
-		btrfs_remove_free_space_cache(block_group);
-		ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
-		ASSERT(list_empty(&block_group->dirty_list));
-		ASSERT(list_empty(&block_group->io_list));
-		ASSERT(list_empty(&block_group->bg_list));
-		ASSERT(atomic_read(&block_group->count) == 1);
-		btrfs_put_block_group(block_group);
-
-		spin_lock(&info->block_group_cache_lock);
-	}
-	spin_unlock(&info->block_group_cache_lock);
-
-	/* now that all the block groups are freed, go through and
-	 * free all the space_info structs.  This is only called during
-	 * the final stages of unmount, and so we know nobody is
-	 * using them.  We call synchronize_rcu() once before we start,
-	 * just to be on the safe side.
-	 */
-	synchronize_rcu();
-
-	btrfs_release_global_block_rsv(info);
-
-	while (!list_empty(&info->space_info)) {
-		space_info = list_entry(info->space_info.next,
-					struct btrfs_space_info,
-					list);
-
-		/*
-		 * Do not hide this behind enospc_debug, this is actually
-		 * important and indicates a real bug if this happens.
-		 */
-		if (WARN_ON(space_info->bytes_pinned > 0 ||
-			    space_info->bytes_reserved > 0 ||
-			    space_info->bytes_may_use > 0))
-			btrfs_dump_space_info(info, space_info, 0, 0);
-		list_del(&space_info->list);
-		btrfs_sysfs_remove_space_info(space_info);
-	}
-	return 0;
-}
-
 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
 				   u64 start, u64 end)
 {