[Bug 258208] [zfs] locks up when using rollback or destroy on both 13.0-RELEASE & sysutils/openzfs port
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Date: Wed, 27 Oct 2021 21:01:12 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=258208 --- Comment #18 from Mark Johnston <markj@FreeBSD.org> --- Some stress testing revealed a couple of problems with the original approach of overriding vop_lock: 1. rms read locks don't permit recursion. This isn't really obvious since nothing asserts that, rms locks need to use witness. 2. Even if reader recursion is permitted, deadlocks can occur when threads lock multiple vnodes (as can happen during lookup). In particular, thread A may be blocked on reader thread B while trying to acquire the teardown write lock, and thread B may be blocked on a vnode lock owned by thread C, which is blocked from acquiring the teardown read lock by thread A. So we'd need some deadlock avoidance mechanism there, or a different approach. -- You are receiving this mail because: You are the assignee for the bug.