Section 16306(a) states the rule that makes a general partnership a risky way to trade: except as otherwise provided in subdivisions (b) and (c), all partners are liable jointly and severally for all obligations of the partnership unless otherwise agreed by the claimant or provided by law. Joint and several means a creditor may pursue any one partner for the whole of a partnership debt, not merely that partner's share, leaving the partner who paid to seek contribution from the others.
Subdivision (b) contains the protection for someone joining an existing firm: a person admitted as a partner is not personally liable for any partnership obligation incurred before their admission. Liabilities already on the books stay with the partnership and the partners who were there.
Subdivision (c) is the registered limited liability partnership exception, and it is substantial: a partner in a registered LLP is not liable or accountable, directly or indirectly, including by way of indemnification, contribution or assessment, for debts, obligations or liabilities of or chargeable to the partnership or another partner, whether in tort, contract or otherwise, incurred while the partnership is a registered LLP, by reason of being a partner or acting in the conduct of the business. That protection is subject to important limits: under subdivision (d) specified partners may agree in writing to be liable for specified debts, and under subdivision (e) nothing in subdivision (c) affects a partner's liability to third parties for that partner's own tortious conduct. A partner who does the negligent work is answerable for it whatever the form of the firm. Whether a business is a general partnership or a registered LLP, and what a particular partner is exposed to, is a question to settle with a lawyer before the debts arise.