Commit f7238e50 authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: add support for multiple global roots 



With extent tree v2 you will be able to create multiple csum, extent,
and free space trees.  They will be used based on the block group, which
will now use the block_group_item->chunk_objectid to point to the set of
global roots that it will use.  When allocating new block groups we'll
simply mod the gigabyte offset of the block group against the number of
global roots we have and that will be the block groups global id.

>From there we can take the bytenr that we're modifying in the respective
tree, look up the block group and get that block groups corresponding
global root id.  From there we can get to the appropriate global root
for that bytenr.

Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 9c54e80d

fs/btrfs/block-group.c

+26 −2
Original line number Diff line number Diff line
@@ -2006,6 +2006,7 @@ static int read_one_block_group(struct btrfs_fs_info *info, 
	cache->length = key->offset;

	cache->used = btrfs_stack_block_group_used(bgi);

	cache->flags = btrfs_stack_block_group_flags(bgi);

	cache->global_root_id = btrfs_stack_block_group_chunk_objectid(bgi);



	set_free_space_tree_thresholds(cache);
@@ -2288,7 +2289,7 @@ static int insert_block_group_item(struct btrfs_trans_handle *trans, 
	spin_lock(&block_group->lock);

	btrfs_set_stack_block_group_used(&bgi, block_group->used);

	btrfs_set_stack_block_group_chunk_objectid(&bgi,

				BTRFS_FIRST_CHUNK_TREE_OBJECTID);

						   block_group->global_root_id);

	btrfs_set_stack_block_group_flags(&bgi, block_group->flags);

	key.objectid = block_group->start;

	key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
@@ -2444,6 +2445,27 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) 
	btrfs_trans_release_chunk_metadata(trans);

}



/*

 * For extent tree v2 we use the block_group_item->chunk_offset to point at our

 * global root id.  For v1 it's always set to BTRFS_FIRST_CHUNK_TREE_OBJECTID.

 */

static u64 calculate_global_root_id(struct btrfs_fs_info *fs_info, u64 offset)

{

	u64 div = SZ_1G;

	u64 index;



	if (!btrfs_fs_incompat(fs_info, EXTENT_TREE_V2))

		return BTRFS_FIRST_CHUNK_TREE_OBJECTID;



	/* If we have a smaller fs index based on 128MiB. */

	if (btrfs_super_total_bytes(fs_info->super_copy) <= (SZ_1G * 10ULL))

		div = SZ_128M;



	offset = div64_u64(offset, div);

	div64_u64_rem(offset, fs_info->nr_global_roots, &index);

	return index;

}



struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *trans,

						 u64 bytes_used, u64 type,

						 u64 chunk_offset, u64 size)
@@ -2464,6 +2486,8 @@ struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *tran 
	cache->flags = type;

	cache->last_byte_to_unpin = (u64)-1;

	cache->cached = BTRFS_CACHE_FINISHED;

	cache->global_root_id = calculate_global_root_id(fs_info, cache->start);



	if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))

		cache->needs_free_space = 1;
@@ -2693,7 +2717,7 @@ static int update_block_group_item(struct btrfs_trans_handle *trans, 
	bi = btrfs_item_ptr_offset(leaf, path->slots[0]);

	btrfs_set_stack_block_group_used(&bgi, cache->used);

	btrfs_set_stack_block_group_chunk_objectid(&bgi,

			BTRFS_FIRST_CHUNK_TREE_OBJECTID);

						   cache->global_root_id);

	btrfs_set_stack_block_group_flags(&bgi, cache->flags);

	write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));

	btrfs_mark_buffer_dirty(leaf);

fs/btrfs/block-group.h

+1 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ struct btrfs_block_group { 
	u64 bytes_super;

	u64 flags;

	u64 cache_generation;

	u64 global_root_id;



	/*

	 * If the free space extent count exceeds this number, convert the block

fs/btrfs/ctree.h

+2 −0
Original line number Diff line number Diff line
@@ -1058,6 +1058,8 @@ struct btrfs_fs_info { 
	spinlock_t relocation_bg_lock;

	u64 data_reloc_bg;



	u64 nr_global_roots;



	spinlock_t zone_active_bgs_lock;

	struct list_head zone_active_bgs;

fs/btrfs/disk-io.c

+41 −9
Original line number Diff line number Diff line
@@ -1289,12 +1289,33 @@ struct btrfs_root *btrfs_global_root(struct btrfs_fs_info *fs_info, 
	return root;

}



static u64 btrfs_global_root_id(struct btrfs_fs_info *fs_info, u64 bytenr)

{

	struct btrfs_block_group *block_group;

	u64 ret;



	if (!btrfs_fs_incompat(fs_info, EXTENT_TREE_V2))

		return 0;



	if (bytenr)

		block_group = btrfs_lookup_block_group(fs_info, bytenr);

	else

		block_group = btrfs_lookup_first_block_group(fs_info, bytenr);

	ASSERT(block_group);

	if (!block_group)

		return 0;

	ret = block_group->global_root_id;

	btrfs_put_block_group(block_group);



	return ret;

}



struct btrfs_root *btrfs_csum_root(struct btrfs_fs_info *fs_info, u64 bytenr)

{

	struct btrfs_key key = {

		.objectid = BTRFS_CSUM_TREE_OBJECTID,

		.type = BTRFS_ROOT_ITEM_KEY,

		.offset = 0,

		.offset = btrfs_global_root_id(fs_info, bytenr),

	};



	return btrfs_global_root(fs_info, &key);
@@ -1305,7 +1326,7 @@ struct btrfs_root *btrfs_extent_root(struct btrfs_fs_info *fs_info, u64 bytenr) 
	struct btrfs_key key = {

		.objectid = BTRFS_EXTENT_TREE_OBJECTID,

		.type = BTRFS_ROOT_ITEM_KEY,

		.offset = 0,

		.offset = btrfs_global_root_id(fs_info, bytenr),

	};



	return btrfs_global_root(fs_info, &key);
@@ -2096,7 +2117,6 @@ static void backup_super_roots(struct btrfs_fs_info *info) 
{

	const int next_backup = info->backup_root_index;

	struct btrfs_root_backup *root_backup;

	struct btrfs_root *csum_root = btrfs_csum_root(info, 0);



	root_backup = info->super_for_commit->super_roots + next_backup;
@@ -2130,6 +2150,7 @@ static void backup_super_roots(struct btrfs_fs_info *info) 
			btrfs_header_level(info->block_group_root->node));

	} else {

		struct btrfs_root *extent_root = btrfs_extent_root(info, 0);

		struct btrfs_root *csum_root = btrfs_csum_root(info, 0);



		btrfs_set_backup_extent_root(root_backup,

					     extent_root->node->start);
@@ -2137,6 +2158,12 @@ static void backup_super_roots(struct btrfs_fs_info *info) 
				btrfs_header_generation(extent_root->node));

		btrfs_set_backup_extent_root_level(root_backup,

					btrfs_header_level(extent_root->node));



		btrfs_set_backup_csum_root(root_backup, csum_root->node->start);

		btrfs_set_backup_csum_root_gen(root_backup,

					       btrfs_header_generation(csum_root->node));

		btrfs_set_backup_csum_root_level(root_backup,

						 btrfs_header_level(csum_root->node));

	}



	/*
@@ -2158,12 +2185,6 @@ static void backup_super_roots(struct btrfs_fs_info *info) 
	btrfs_set_backup_dev_root_level(root_backup,

				       btrfs_header_level(info->dev_root->node));



	btrfs_set_backup_csum_root(root_backup, csum_root->node->start);

	btrfs_set_backup_csum_root_gen(root_backup,

				       btrfs_header_generation(csum_root->node));

	btrfs_set_backup_csum_root_level(root_backup,

					 btrfs_header_level(csum_root->node));



	btrfs_set_backup_total_bytes(root_backup,

			     btrfs_super_total_bytes(info->super_copy));

	btrfs_set_backup_bytes_used(root_backup,
@@ -2546,6 +2567,7 @@ static int load_global_roots_objectid(struct btrfs_root *tree_root, 
{

	struct btrfs_fs_info *fs_info = tree_root->fs_info;

	struct btrfs_root *root;

	u64 max_global_id = 0;

	int ret;

	struct btrfs_key key = {

		.objectid = objectid,
@@ -2581,6 +2603,13 @@ static int load_global_roots_objectid(struct btrfs_root *tree_root, 
			break;

		btrfs_release_path(path);



		/*

		 * Just worry about this for extent tree, it'll be the same for

		 * everybody.

		 */

		if (objectid == BTRFS_EXTENT_TREE_OBJECTID)

			max_global_id = max(max_global_id, key.offset);



		found = true;

		root = read_tree_root_path(tree_root, path, &key);

		if (IS_ERR(root)) {
@@ -2598,6 +2627,9 @@ static int load_global_roots_objectid(struct btrfs_root *tree_root, 
	}

	btrfs_release_path(path);



	if (objectid == BTRFS_EXTENT_TREE_OBJECTID)

		fs_info->nr_global_roots = max_global_id + 1;



	if (!found || ret) {

		if (objectid == BTRFS_CSUM_TREE_OBJECTID)

			set_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state);

fs/btrfs/free-space-tree.c

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ static struct btrfs_root *btrfs_free_space_root( 
		.offset = 0,

	};



	if (btrfs_fs_incompat(block_group->fs_info, EXTENT_TREE_V2))

		key.offset = block_group->global_root_id;

	return btrfs_global_root(block_group->fs_info, &key);

}