Date: Fri, 15 Sep 2017 17:02:03 +0100 From: Edward Napierala <trasz@freebsd.org> To: Andriy Gapon <avg@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, Kirk McKusick <mckusick@mckusick.com>, freebsd-fs <freebsd-fs@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: mount / unmount and mountcheckdirs() Message-ID: <CAFLM3-rEo1wwYpgV5rmm8wXuCPKXM8it3sp5om%2BVna53_%2BjF0g@mail.gmail.com> In-Reply-To: <f84704ce-3596-86d0-3c41-6256a7aae8d1@FreeBSD.org> References: <134c7c6e-f4f1-ef38-cc50-0e56c27c9fb8@FreeBSD.org> <201709150314.v8F3Ea6B085072@chez.mckusick.com> <20170915092001.GK78693@kib.kiev.ua> <CAFLM3-rqg9Pso636Y3Vm6JT0WxWossEfvnsMmmAbC-jEkvyS7Q@mail.gmail.com> <f84704ce-3596-86d0-3c41-6256a7aae8d1@FreeBSD.org>
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2017-09-15 12:56 GMT+01:00 Andriy Gapon <avg@freebsd.org>: > 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.
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