C++ btrfs_header_nritems函数代码示例

void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *eb, int follow)
{
	int i;
	u32 nr;
	u32 size;
	struct btrfs_disk_key disk_key;
	struct btrfs_key key;

	if (!eb)
		return;
	nr = btrfs_header_nritems(eb);
	if (btrfs_is_leaf(eb)) {
		btrfs_print_leaf(root, eb);
		return;
	}
	printf("node %llu level %d items %d free %u generation %llu owner %llu\n",
	       (unsigned long long)eb->start,
	        btrfs_header_level(eb), nr,
		(u32)BTRFS_NODEPTRS_PER_BLOCK(root) - nr,
		(unsigned long long)btrfs_header_generation(eb),
		(unsigned long long)btrfs_header_owner(eb));
	print_uuids(eb);
	fflush(stdout);
	size = btrfs_level_size(root, btrfs_header_level(eb) - 1);
	for (i = 0; i < nr; i++) {
		u64 blocknr = btrfs_node_blockptr(eb, i);
		btrfs_node_key(eb, &disk_key, i);
		btrfs_disk_key_to_cpu(&key, &disk_key);
		printf("\t");
		btrfs_print_key(&disk_key);
		printf(" block %llu (%llu) gen %llu\n",
		       (unsigned long long)blocknr,
		       (unsigned long long)blocknr / size,
		       (unsigned long long)btrfs_node_ptr_generation(eb, i));
		fflush(stdout);
	}
	if (!follow)
		return;

	for (i = 0; i < nr; i++) {
		struct extent_buffer *next = read_tree_block(root,
					     btrfs_node_blockptr(eb, i),
					     size,
					     btrfs_node_ptr_generation(eb, i));
		if (!next) {
			fprintf(stderr, "failed to read %llu in tree %llu\n",
				(unsigned long long)btrfs_node_blockptr(eb, i),
				(unsigned long long)btrfs_header_owner(eb));
			continue;
		}
		if (btrfs_is_leaf(next) &&
		    btrfs_header_level(eb) != 1)
			BUG();
		if (btrfs_header_level(next) !=
			btrfs_header_level(eb) - 1)
			BUG();
		btrfs_print_tree(root, next, 1);
		free_extent_buffer(next);
	}
}

static int __inode_info(u64 inum, u64 ioff, u8 key_type,
			struct btrfs_root *fs_root, struct btrfs_path *path,
			struct btrfs_key *found_key)
{
	int ret;
	struct btrfs_key key;
	struct extent_buffer *eb;

	key.type = key_type;
	key.objectid = inum;
	key.offset = ioff;

	ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
	if (ret < 0)
		return ret;

	eb = path->nodes[0];
	if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
		ret = btrfs_next_leaf(fs_root, path);
		if (ret)
			return ret;
		eb = path->nodes[0];
	}

	btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
	if (found_key->type != key.type || found_key->objectid != key.objectid)
		return 1;

	return 0;
}

/*
 * helper for dropping snapshots.  This walks back up the tree in the path
 * to find the first node higher up where we haven't yet gone through
 * all the slots
 */
static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
			*root, struct btrfs_path *path, int *level)
{
	int i;
	int slot;
	int ret;
	for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
		slot = path->slots[i];
		if (slot <
		    btrfs_header_nritems(&path->nodes[i]->node.header)- 1) {
			path->slots[i]++;
			*level = i;
			return 0;
		} else {
			ret = btrfs_free_extent(trans, root,
						path->nodes[*level]->blocknr,
						1, 1);
			btrfs_block_release(root, path->nodes[*level]);
			path->nodes[*level] = NULL;
			*level = i + 1;
			BUG_ON(ret);
		}
	}
	return 1;
}

static void print_extents(struct btrfs_root *root, struct extent_buffer *eb)
{
    int i;
    u32 nr;
    u32 size;

    if (!eb)
        return;

    if (btrfs_is_leaf(eb)) {
        btrfs_print_leaf(root, eb);
        return;
    }

    size = btrfs_level_size(root, btrfs_header_level(eb) - 1);
    nr = btrfs_header_nritems(eb);
    for (i = 0; i < nr; i++) {
        struct extent_buffer *next = read_tree_block(root,
                                     btrfs_node_blockptr(eb, i),
                                     size,
                                     btrfs_node_ptr_generation(eb, i));
        if (!extent_buffer_uptodate(next))
            continue;
        if (btrfs_is_leaf(next) &&
                btrfs_header_level(eb) != 1)
            BUG();
        if (btrfs_header_level(next) !=
                btrfs_header_level(eb) - 1)
            BUG();
        print_extents(root, next);
        free_extent_buffer(next);
    }
}

struct btrfs_dir_item *
btrfs_search_dir_index_item(struct btrfs_root *root,
			    struct btrfs_path *path, u64 dirid,
			    const char *name, int name_len)
{
	struct extent_buffer *leaf;
	struct btrfs_dir_item *di;
	struct btrfs_key key;
	u32 nritems;
	int ret;

	key.objectid = dirid;
	key.type = BTRFS_DIR_INDEX_KEY;
	key.offset = 0;

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		return ERR_PTR(ret);

	leaf = path->nodes[0];
	nritems = btrfs_header_nritems(leaf);

	while (1) {
		if (path->slots[0] >= nritems) {
			ret = btrfs_next_leaf(root, path);
			if (ret < 0)
				return ERR_PTR(ret);
			if (ret > 0)
				break;
			leaf = path->nodes[0];
			nritems = btrfs_header_nritems(leaf);
			continue;
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
		if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
			break;

		di = btrfs_match_dir_item_name(root->fs_info, path,
					       name, name_len);
		if (di)
			return di;

		path->slots[0]++;
	}
	return NULL;
}

static int next_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
	int slot;
	int level = 1;
	int offset = 1;
	struct extent_buffer *c;
	struct extent_buffer *next = NULL;
	struct btrfs_fs_info *fs_info = root->fs_info;

again:
	for (; level < BTRFS_MAX_LEVEL; level++) {
		if (path->nodes[level])
			break;
	}

	if (level >= BTRFS_MAX_LEVEL)
		return 1;

	slot = path->slots[level] + 1;

	while(level < BTRFS_MAX_LEVEL) {
		if (!path->nodes[level])
			return 1;

		slot = path->slots[level] + offset;
		c = path->nodes[level];
		if (slot >= btrfs_header_nritems(c)) {
			level++;
			if (level == BTRFS_MAX_LEVEL)
				return 1;
			offset = 1;
			continue;
		}

		if (path->reada)
			reada_for_search(fs_info, path, level, slot, 0);

		next = read_node_slot(fs_info, c, slot);
		if (extent_buffer_uptodate(next))
			break;
		offset++;
	}
	path->slots[level] = slot;
	while(1) {
		level--;
		c = path->nodes[level];
		free_extent_buffer(c);
		path->nodes[level] = next;
		path->slots[level] = 0;
		if (!level)
			break;
		if (path->reada)
			reada_for_search(fs_info, path, level, 0, 0);
		next = read_node_slot(fs_info, next, 0);
		if (!extent_buffer_uptodate(next))
			goto again;
	}
	return 0;
}

int next_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
	int slot;
	int level = 1;
	struct extent_buffer *c;
	struct extent_buffer *next = NULL;

	for (; level < BTRFS_MAX_LEVEL; level++) {
		if (path->nodes[level])
			break;
	}

	if (level == BTRFS_MAX_LEVEL)
		return 1;

	slot = path->slots[level] + 1;

	while(level < BTRFS_MAX_LEVEL) {
		if (!path->nodes[level])
			return 1;

		slot = path->slots[level] + 1;
		c = path->nodes[level];
		if (slot >= btrfs_header_nritems(c)) {
			level++;
			if (level == BTRFS_MAX_LEVEL)
				return 1;
			continue;
		}

		if (next)
			free_extent_buffer(next);

		if (path->reada)
			reada_for_search(root, path, level, slot, 0);

		next = read_node_slot(root, c, slot);
		break;
	}
	path->slots[level] = slot;
	while(1) {
		level--;
		c = path->nodes[level];
		free_extent_buffer(c);
		path->nodes[level] = next;
		path->slots[level] = 0;
		if (!level)
			break;
		if (path->reada)
			reada_for_search(root, path, level, 0, 0);
		next = read_node_slot(root, next, 0);
	}
	return 0;
}

int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
{
	struct extent_buffer *leaf;
	struct btrfs_path *path;
	struct btrfs_key key;
	int err = 0;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	key.objectid = BTRFS_ORPHAN_OBJECTID;
	key.type = BTRFS_ORPHAN_ITEM_KEY;
	key.offset = 0;

	while (1) {
		ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
		if (ret < 0) {
			err = ret;
			break;
		}

		leaf = path->nodes[0];
		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
			ret = btrfs_next_leaf(tree_root, path);
			if (ret < 0)
				err = ret;
			if (ret != 0)
				break;
			leaf = path->nodes[0];
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
		btrfs_release_path(tree_root, path);

		if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
		    key.type != BTRFS_ORPHAN_ITEM_KEY)
			break;

		ret = btrfs_find_dead_roots(tree_root, key.offset);
		if (ret) {
			err = ret;
			break;
		}

		key.offset++;
	}

	btrfs_free_path(path);
	return err;
}

/*
 * helper function for drop_snapshot, this walks down the tree dropping ref
 * counts as it goes.
 */
static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
			  *root, struct btrfs_path *path, int *level)
{
	struct btrfs_buffer *next;
	struct btrfs_buffer *cur;
	u64 blocknr;
	int ret;
	u32 refs;

	ret = lookup_block_ref(trans, root, path->nodes[*level]->blocknr,
			       &refs);
	BUG_ON(ret);
	if (refs > 1)
		goto out;
	/*
	 * walk down to the last node level and free all the leaves
	 */
	while(*level > 0) {
		cur = path->nodes[*level];
		if (path->slots[*level] >=
		    btrfs_header_nritems(&cur->node.header))
			break;
		blocknr = btrfs_node_blockptr(&cur->node, path->slots[*level]);
		ret = lookup_block_ref(trans, root, blocknr, &refs);
		if (refs != 1 || *level == 1) {
			path->slots[*level]++;
			ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
			BUG_ON(ret);
			continue;
		}
		BUG_ON(ret);
		next = read_tree_block(root, blocknr);
		if (path->nodes[*level-1])
			btrfs_block_release(root, path->nodes[*level-1]);
		path->nodes[*level-1] = next;
		*level = btrfs_header_level(&next->node.header);
		path->slots[*level] = 0;
	}
out:
	ret = btrfs_free_extent(trans, root, path->nodes[*level]->blocknr, 1,
				1);
	btrfs_block_release(root, path->nodes[*level]);
	path->nodes[*level] = NULL;
	*level += 1;
	BUG_ON(ret);
	return 0;
}

int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		  struct btrfs_buffer *buf)
{
	u64 blocknr;
	int i;

	if (!root->ref_cows)
		return 0;
	if (btrfs_is_leaf(&buf->node))
		return 0;

	for (i = 0; i < btrfs_header_nritems(&buf->node.header); i++) {
		blocknr = btrfs_node_blockptr(&buf->node, i);
		inc_block_ref(trans, root, blocknr);
	}
	return 0;
}

void btrfs_print_tree(struct btrfs_fs_info *fs_info, struct extent_buffer *c)
{
	int i; u32 nr;
	struct btrfs_key key;
	int level;

	if (!c)
		return;
	nr = btrfs_header_nritems(c);
	level = btrfs_header_level(c);
	if (level == 0) {
		btrfs_print_leaf(fs_info, c);
		return;
	}
	btrfs_info(fs_info,
		   "node %llu level %d total ptrs %d free spc %u",
		   btrfs_header_bytenr(c), level, nr,
		   (u32)BTRFS_NODEPTRS_PER_BLOCK(fs_info) - nr);
	for (i = 0; i < nr; i++) {
		btrfs_node_key_to_cpu(c, &key, i);
		pr_info("\tkey %d (%llu %u %llu) block %llu\n",
		       i, key.objectid, key.type, key.offset,
		       btrfs_node_blockptr(c, i));
	}
	for (i = 0; i < nr; i++) {
		struct extent_buffer *next = read_tree_block(fs_info,
					btrfs_node_blockptr(c, i),
					btrfs_node_ptr_generation(c, i));
		if (IS_ERR(next)) {
			continue;
		} else if (!extent_buffer_uptodate(next)) {
			free_extent_buffer(next);
			continue;
		}

		if (btrfs_is_leaf(next) &&
		   level != 1)
			BUG();
		if (btrfs_header_level(next) !=
		       level - 1)
			BUG();
		btrfs_print_tree(fs_info, next);
		free_extent_buffer(next);
	}
}

void btrfs_print_tree(struct btrfs_root *root, struct btrfs_buffer *t)
{
	unsigned int i;
	u32 nr;
	struct btrfs_node *c;

	if (!t)
		return;
	c = &t->node;
	nr = btrfs_header_nritems(&c->header);
	if (btrfs_is_leaf(c)) {
		btrfs_print_leaf(root, (struct btrfs_leaf *)c);
		return;
	}
	printf("node %llu level %d ptrs %d free %u generation %llu owner %llu\n",
	       (u64)t->blocknr,
	        btrfs_header_level(&c->header), nr,
		(u32)BTRFS_NODEPTRS_PER_BLOCK(root) - nr,
		(u64)btrfs_header_generation(&c->header),
		(u64)btrfs_header_owner(&c->header));
	fflush(stdout);
	for (i = 0; i < nr; i++) {
		printf("\tkey %d (%llu %x %llu) block %llu\n",
		       i,
		       (u64)c->ptrs[i].key.objectid,
		       c->ptrs[i].key.flags,
		       (u64)c->ptrs[i].key.offset,
		       (u64)btrfs_node_blockptr(c, i));
		fflush(stdout);
	}
	for (i = 0; i < nr; i++) {
		struct btrfs_buffer *next_buf = read_tree_block(root,
						btrfs_node_blockptr(c, i));
		struct btrfs_node *next = &next_buf->node;
		if (btrfs_is_leaf(next) &&
		    btrfs_header_level(&c->header) != 1)
			BUG();
		if (btrfs_header_level(&next->header) !=
			btrfs_header_level(&c->header) - 1)
			BUG();
		btrfs_print_tree(root, next_buf);
		btrfs_block_release(root, next_buf);
	}
}

/*
 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
 * looking for.
 */
static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
                                  struct btrfs_root *root, struct btrfs_path *p)
{
    struct btrfs_key key;

    if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
        p->slots[0]++;
        return 0;
    }

    btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
    btrfs_release_path(p);

    key.objectid += key.offset;
    key.type = (u8)-1;
    key.offset = (u64)-1;

    return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
}

void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *c)
{
	int i; u32 nr;
	struct btrfs_key key;
	int level;

	if (!c)
		return;
	nr = btrfs_header_nritems(c);
	level = btrfs_header_level(c);
	if (level == 0) {
		btrfs_print_leaf(root, c);
		return;
	}
	printk(KERN_INFO "node %llu level %d total ptrs %d free spc %u\n",
	       (unsigned long long)btrfs_header_bytenr(c),
	      level, nr,
	       (u32)BTRFS_NODEPTRS_PER_BLOCK(root) - nr);
	for (i = 0; i < nr; i++) {
		btrfs_node_key_to_cpu(c, &key, i);
		printk(KERN_INFO "\tkey %d (%llu %u %llu) block %llu\n",
		       i,
		       (unsigned long long)key.objectid,
		       key.type,
		       (unsigned long long)key.offset,
		       (unsigned long long)btrfs_node_blockptr(c, i));
	}
	for (i = 0; i < nr; i++) {
		struct extent_buffer *next = read_tree_block(root,
					btrfs_node_blockptr(c, i),
					btrfs_level_size(root, level - 1),
					btrfs_node_ptr_generation(c, i));
		if (btrfs_is_leaf(next) &&
		   level != 1)
			BUG();
		if (btrfs_header_level(next) !=
		       level - 1)
			BUG();
		btrfs_print_tree(root, next);
		free_extent_buffer(next);
	}
}

static int clear_free_space_tree(struct btrfs_trans_handle *trans,
                                 struct btrfs_root *root)
{
    struct btrfs_path *path;
    struct btrfs_key key;
    int nr;
    int ret;

    path = btrfs_alloc_path();
    if (!path)
        return -ENOMEM;

    path->leave_spinning = 1;

    key.objectid = 0;
    key.type = 0;
    key.offset = 0;

    while (1) {
        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
        if (ret < 0)
            goto out;

        nr = btrfs_header_nritems(path->nodes[0]);
        if (!nr)
            break;

        path->slots[0] = 0;
        ret = btrfs_del_items(trans, root, path, 0, nr);
        if (ret)
            goto out;

        btrfs_release_path(path);
    }

    ret = 0;
out:
    btrfs_free_path(path);
    return ret;
}