Date: Fri, 10 Jun 2011 11:32:52 -0600 From: "Justin T. Gibbs" <gibbs@FreeBSD.org> To: fs@FreeBSD.org Subject: Drop of spa_namespace lock in vdev_geom.c Message-ID: <4DF25544.3020301@FreeBSD.org>
next in thread | raw e-mail | index | archive | help
Dropping and reacquiring the spa_namespace lock in vdev_geom_open() creates a lock order reversal with the spa_config locks. As the spa_config locks are not standard mutexes, witness will not warn about this issue. I only noticed this problem when debugging a ZFS deadlock. The deadlock can be triggered anytime that there are multiple insert/remove processes going on (e.g. vdev orphan processing while a fault management daemon is onlining a replacement device for some other vdev). I haven't noticed any issues with just holding the namespace lock for the duration of the open. Does anyone know why this lock drop was added in v28? Thanks, Justin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4DF25544.3020301>