Date: Mon, 6 Nov 2017 08:58:25 +0000 From: Colin Percival <cperciva@tarsnap.com> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: freebsd-geom@freebsd.org Subject: Re: No automatic root mount holding for new geom providers? Message-ID: <0100015f908d5f88-f54848aa-5a30-4571-865d-5f1e0c3dca32-000000@email.amazonses.com> In-Reply-To: <31857.1509955550@critter.freebsd.dk> References: <0100015f900017eb-91becde5-26c8-49f0-b593-751670ca42e0-000000@email.amazonses.com> <31857.1509955550@critter.freebsd.dk>
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On 11/06/17 00:05, Poul-Henning Kamp wrote: > Colin Percival writes: >> In practice, it seems that we avoid this by virtue of tasting new geoms being >> much faster than everything else the kernel does between when the disks are >> attached and when vfs_mountroot runs, but I wouldn't want to rely on that. >> >> Am I missing something? > > As I recall, the actual open will stall on the non-empty event-queue. Aha! I'm not sure about opens, but vfs_mountroot_wait calls g_waitidle, which waits until the event queue is empty. So any devices discovered before we hit vfs_mountroot will indeed have been fully digested before we try to mount the root filesystem. Thanks! -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid
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