From owner-freebsd-arch@freebsd.org Fri Sep 15 16:02:05 2017 Return-Path: Delivered-To: freebsd-arch@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B37B8E1F52A; Fri, 15 Sep 2017 16:02:05 +0000 (UTC) (envelope-from etnapierala@gmail.com) Received: from mail-ua0-x229.google.com (mail-ua0-x229.google.com [IPv6:2607:f8b0:400c:c08::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 67B346D643; Fri, 15 Sep 2017 16:02:05 +0000 (UTC) (envelope-from etnapierala@gmail.com) Received: by mail-ua0-x229.google.com with SMTP id c27so1476635uah.2; Fri, 15 Sep 2017 09:02:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=aTqGj5uk1GG7tfE+vU6w9obFTF6Vdz5wtzR1inaQaVY=; b=vgo6jRb5lRk1OnaEsc2HMv3ESvQlsN0/VAwAFwXf1mQF2/aRnlZ3OmlISE3MdzStv9 6ecG6KzvzH8hIv68FGTeD8bmYPpTg9ElFp61BaIDQpTThxoZxbYEPoID37w9GXpXVu7f s+llTtQ24FpZQ6lT030x5CzYfqpVo2nnQ2t7fMMmUgd/VEs5uxkbQlrma6564u+F+K0U XIyu1Jrt1p6DaM7sAxa/G1pNB1R5H/zbbXWdMLmmX9Rbm0rI7GcHxZLgrGowsSSrzxc3 O3loVa4oG6xnXd4jKBrGv4T4Qt9B1btcafBajlmK0n9dlECRQ/mB/fHtoFwhsfUnbj6k m6dQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=aTqGj5uk1GG7tfE+vU6w9obFTF6Vdz5wtzR1inaQaVY=; b=eu+3xhS50dzGwzPryvgQdSO9vc/nONUd6N29mMFTHkyD+GaWfkkJS3sNiIT5nkh5cT d7RS++gaVwZRhg/N8kwfoBfl4dVIxA+ANmO1Wd8rqXaMSd1WZ0Bpqf3fs+xtdcki7xd3 imQwM7OtWDMqLpqRWgTauhg2b+cJuBmbJ/60dCS4wh0SYJa0QXYEfEf0a3I4jxA7vSiR plUv3R4E3pPXfqsLekJJeTYjq4x37i+S1x9cTu1AGLFLcIdWVJtbo6eMTvy2RB8U9ytP QO93QHrFdbMuq4XxwaFPkxLI3PO5PvcBFvpIOaDwFk8u0ejkQd1+BgTh/6tdbaj1NqHv br7Q== X-Gm-Message-State: AHPjjUiEBQxY8ilnCc35oYiIZ7+XoC9KSANlt0AFKKWppJgSAl7leSYd fuVCR7nPtH2/X6AFJbgFR0OROR1QO1eDCQonfhI= X-Google-Smtp-Source: ADKCNb7RmgZhGgKJq+HyxU7oDSIZ0S6E1vdo7E1BCrBeM64NEjco6mS1JxJNzvam1JIxl5DqhVGWwI/1eonwk5Rww40= X-Received: by 10.176.92.111 with SMTP id a47mr22014144uag.111.1505491324300; Fri, 15 Sep 2017 09:02:04 -0700 (PDT) MIME-Version: 1.0 Sender: etnapierala@gmail.com Received: by 10.159.51.232 with HTTP; Fri, 15 Sep 2017 09:02:03 -0700 (PDT) In-Reply-To: References: <134c7c6e-f4f1-ef38-cc50-0e56c27c9fb8@FreeBSD.org> <201709150314.v8F3Ea6B085072@chez.mckusick.com> <20170915092001.GK78693@kib.kiev.ua> From: Edward Napierala Date: Fri, 15 Sep 2017 17:02:03 +0100 X-Google-Sender-Auth: YQoXymOHcUVy7BkjINTxt8_Zdv0 Message-ID: Subject: Re: mount / unmount and mountcheckdirs() To: Andriy Gapon Cc: Konstantin Belousov , Kirk McKusick , freebsd-fs , "freebsd-arch@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.23 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 15 Sep 2017 16:02:05 -0000 2017-09-15 12:56 GMT+01:00 Andriy Gapon : > On 15/09/2017 13:08, Edward Napierala wrote: > > It does. For example: > > > > [trasz@v2:~]% cd /media/md0 > > [trasz@v2:/media/md0]% mount > > /dev/ada0s1a on / (ufs, local, noatime, journaled soft-updates) > > devfs on /dev (devfs, local, multilabel) > > map -hosts on /net (autofs) > > map -media on /media (autofs) > > Interesting, I thought that /dev/md0 would get mounted as soon as > /media/md0 is > looked up. But maybe that would be sub-optimal for some common > scenarios... > FWIW, ZFS snapshots get auto-mounted under .zfs as soon as there is a > lookup. You really don't want it to work that way. If you have a directory with thousands of mountpoints inside, you don't want to mount all of them every time you do "ls" in that directory. Same problem with mounting on "cd". That's why autofs triggers in three cases: in VOP_READDIR(9), VOP_GETATTR(9), and VOP_LOOKUP(9) with the vnode as a parent dir.