Date: Thu, 9 Jun 2016 15:17:05 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Peter Holm <peter@holm.cc> Cc: richard bader <richard@bader-muenchen.de>, freebsd-fs@freebsd.org Subject: Re: disk space not freed when deleting files in null_mounted filesystem Message-ID: <20160609121705.GB38613@kib.kiev.ua> In-Reply-To: <20160609121126.GA46828@x2.osted.lan> References: <2e11d942-0856-7ce4-56ef-3774046f8df8@bader-muenchen.de> <20160609112703.GA42321@x2.osted.lan> <92c2f5f8-a5fc-4947-1e65-252543a2569e@bader-muenchen.de> <20160609121126.GA46828@x2.osted.lan>
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On Thu, Jun 09, 2016 at 02:11:26PM +0200, Peter Holm wrote:
> On Thu, Jun 09, 2016 at 01:39:45PM +0200, richard bader wrote:
> > Am 09.06.2016 um 13:27 schrieb Peter Holm:
> > > On Thu, Jun 09, 2016 at 12:13:08PM +0200, richard bader wrote:
> > >> Hello,
> > >>
> > >> i've a filesystem mounted with mount_nullfs.
> > >> When i delete a large file in this filesystem, the space on the disk is
> > >> not freed.
> > >> The space becomes freed when i unmount the filesystem.
> > >>
> > >>
> > >> to reproduce this:
> > >>
> > >> root@main2:/tmp # mkdir lnk src
> > >> root@main2:/tmp # mount_nullfs src lnk
> > >> root@main2:/tmp # mount | grep lnk
> > >> /tmp/src on /tmp/lnk (nullfs, local)
> > >> root@main2:/tmp # df -h .
> > >> Filesystem Size Used Avail Capacity Mounted on
> > >> /dev/ada0p2 58G 40G 13G 75% /
> > >> root@main2:/tmp # dd if=/dev/zero of=lnk/foo bs=1G count=3
> > >> 3+0 records in
> > >> 3+0 records out
> > >> 3221225472 bytes transferred in 7.856793 secs (409992411 bytes/sec)
> > >> root@main2:/tmp # df -h .
> > >> Filesystem Size Used Avail Capacity Mounted on
> > >> /dev/ada0p2 58G 43G 10G 80% /
> > >> root@main2:/tmp # rm lnk/foo
> > >> root@main2:/tmp # df -h .
> > >> Filesystem Size Used Avail Capacity Mounted on
> > >> /dev/ada0p2 58G 43G 10G 80% /
> > >> root@main2:/tmp # umount /tmp/lnk
> > >> root@main2:/tmp # df -h .
> > >> Filesystem Size Used Avail Capacity Mounted on
> > >> /dev/ada0p2 58G 40G 13G 75% /
> > >>
> > >>
> > >> my system:
> > >>
> > >> root@main2:/tmp # uname -a
> > >> FreeBSD main2.bader.loc 10.2-RELEASE-p18 FreeBSD 10.2-RELEASE-p18 #8
> > >> r301112: Wed Jun 1 11:08:24 CEST 2016
> > >> root@main2.bader.loc:/usr/obj/usr/src/sys/MYKERNEL amd64
> > >>
> > >> are the any options for mount_nullfs ?
> > >>
> > >> best regards
> > >>
> > >> richard
> > >>
> > > Hello Richard,
> > >
> > > I wonder which file system you are using?
> > > Here's what happens with UFS and current from today:
> > >
> > > $ cat -n richard.sh
> > > 1 #!/bin/sh
> > > 2
> > > 3 uname -a
> > > 4 mount | grep `df -h /tmp | tail -1 | awk '{print $1}'`
> > > 5
> > > 6 cd /tmp
> > > 7 rm -rf lnk src
> > > 8 mkdir lnk src
> > > 9 mount_nullfs src lnk
> > > 10 mount | grep lnk
> > > 11 df -h .
> > > 12 dd if=/dev/zero of=lnk/foo bs=1G count=3
> > > 13 df -h .
> > > 14 rm lnk/foo
> > > 15 df -h .
> > > 16 umount /tmp/lnk
> > > 17 df -h .
> > > $ ./richard.sh
> > > FreeBSD t2.osted.lan 11.0-ALPHA2 FreeBSD 11.0-ALPHA2 #0 r301722: Thu Jun 9 12:09:39 CEST 2016 pho@t2.osted.lan:/usr/src/sys/amd64/compile/PHO amd64
> > > /dev/da0p3 on /tmp (ufs, NFS exported, local, soft-updates)
> > > /tmp/src on /tmp/lnk (nullfs, local)
> > > Filesystem Size Used Avail Capacity Mounted on
> > > /dev/da0p3 97G 1,6G 87G 2% /tmp
> > > 3+0 records in
> > > 3+0 records out
> > > 3221225472 bytes transferred in 47.658947 secs (67589102 bytes/sec)
> > > Filesystem Size Used Avail Capacity Mounted on
> > > /dev/da0p3 97G 4,6G 84G 5% /tmp
> > > Filesystem Size Used Avail Capacity Mounted on
> > > /dev/da0p3 97G 1,6G 87G 2% /tmp
> > > Filesystem Size Used Avail Capacity Mounted on
> > > /dev/da0p3 97G 1,6G 87G 2% /tmp
> > > $
> > >
> > > - Peter
> > i'm also using ufs.
> >
> > root@main2:/tmp # ./richard.sh
> > FreeBSD main2.bader.loc 10.2-RELEASE-p18 FreeBSD 10.2-RELEASE-p18 #8
> > r301112: Wed Jun 1 11:08:24 CEST 2016
> > root@main2.bader.loc:/usr/obj/usr/src/sys/MYKERNEL amd64
> > /dev/ada0p2 on / (ufs, local, journaled soft-updates)
> > /tmp/src on /tmp/lnk (nullfs, local)
> > Filesystem Size Used Avail Capacity Mounted on
> > /dev/ada0p2 58G 40G 13G 75% /
> > 3+0 records in
> > 3+0 records out
> > 3221225472 bytes transferred in 8.679717 secs (371121023 bytes/sec)
> > Filesystem Size Used Avail Capacity Mounted on
> > /dev/ada0p2 58G 43G 10G 80% /
> > Filesystem Size Used Avail Capacity Mounted on
> > /dev/ada0p2 58G 43G 10G 80% /
> > Filesystem Size Used Avail Capacity Mounted on
> > /dev/ada0p2 58G 40G 13G 75% /
> >
>
> Hmm. I tried again on SU+J but I still do not see any problems on
> HEAD. I'll build r301112 and see what happens.
There were several bugs fixed since 10.2 in nullfs. Use -o nocache
to disable nullfs vnode caching, which most likely fix it for 10.2.
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