Re: nfs bug & df: Can I lock up my kernel and overflow this buffer?

From: Jonathan Noack (noackjr_at_alumni.rice.edu)
Date: 05/10/05

  • Next message: Jared Earle: "Re: freebsd and asus" 
    Date: Tue, 10 May 2005 01:20:59 -0500
To: Billy Newsom <smartweb@leadhill.net>

    On 05/10/05 00:21, Billy Newsom wrote:
    > Jonathan Noack wrote:
    > > On 05/09/05 23:14, Billy Newsom wrote:
    > > From the fstab(5) man page:
    > > "The fourth field, (fs_mntops), describes the mount options associated
    > > with the file system. It is formatted as a comma separated list of
    > > options. It contains at least the type of mount (see fs_type below)
    > > plus any additional options appropriate to the file system type. See
    > > the options flag (-o) in the mount(8) page and the file system specific
    > > page, such as mount_nfs(8), for additional options that may be
    > specified."
    >
    > That is how I read the man page, too, long ago. But when I tried the -o
    > option on the commandline, I was unable to send mount all of the
    > mount_nfs commandline switches I needed. I either misunderstand the
    > mount -o option, or it doesn't work for all of the mount_nfs stuff I
    > tried to send it.
    >
    > In other words, the -o option seems to not like any of the many switches
    > understood by mount_nfs .... hence I seemed to be forced to use
    > mount_nfs directly. And that precludes using it in fstab.

    You are not restricted to only the -o option with fstab. The native
    mount_nfs switches work fine with it. This is stated in the second half
    of the last sentence I quoted above (note the "and"). Thus, the same
    options you use on the command line work with fstab.

    > > What trouble did you have with fstab? You can specify as many options
    > > as you want as long as you separate them with commas (I think putting a
    > > '=' between an option and its value is also necessary, although I don't
    > > know for sure). For you it should look like this (assuming you want
    > > read/write):
    > >
    > > dell:/nfs /dellbak nfs rw,-s,-x=2,-T 0 0
    >
    > I don't know. Since mount wasn't able to understand those switches on
    > the commandline, I never tried anything in fstab, for the sake of not
    > causing any problems with my boot.

    The handbook page on nfs has a few simple examples toward the bottom
    (first hit on a Google search for "freebsd nfs fstab"):
    http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-nfs.html

    To test the line I gave you just add it to /etc/fstab and see if "mount
    /dellbak" works. It'll give you an error message if something is wrong.
      For example, the options specified work perfectly for me and the mount
    command completes successfully. Adding a "-z" to it gives an illegal
    option error.

    # grep shared /etc/fstab
    server:/shared /mnt nfs rw,-s,-x=2,-T 0 0
    # mount /mnt
    # umount /mnt
    <add "-z">
    # grep shared /etc/fstab
    server:/shared /mnt nfs rw,-s,-x=2,-T,-z 0 0
    # mount /mnt
    mount_nfs: illegal option -- z
    usage: mount_nfs [-23bcdiLlNPsTU] [-a maxreadahead] [-D deadthresh]
                      [-g maxgroups] [-I readdirsize] [-o options] [-R retrycnt]
                      [-r readsize] [-t timeout] [-w writesize] [-x retrans]
                      rhost:path node

    > Anyone tried that sort of stuff in fstab? I'm a little skeptical.

    I use "that sort of stuff" and have for a long time. Here's one of my
    fstab lines:

    optimator:/usr/home /usr/home nfs rw,-3,-T,-r=32768,-w=32768 0 0

    It's obvious you don't believe me but why are you unwilling to try it
    yourself? 

    -- 
Jonathan Noack | noackjr@alumni.rice.edu | OpenPGP: 0x991D8195

  • Next message: Jared Earle: "Re: freebsd and asus"

    Relevant Pages

    • Re: nfs bug & df: Can I lock up my kernel and overflow this buffer?
      ... > plus any additional options appropriate to the file system type. ... mount -o option, or it doesn't work for all of the mount_nfs stuff I ... the -o option seems to not like any of the many switches ... And that precludes using it in fstab. ...
      (freebsd-stable)
    • Re: nfs bug & df: Can I lock up my kernel and overflow this buffer?
      ... > I tried tons of different ways, never could get mount to do that, so I ... > the fstab file. ... > but barfs when doing them on the commandline. ... > But what I did discover is that if I mount the same nfs resource ...
      (freebsd-stable)
    • Re: nfs bug & df: Can I lock up my kernel and overflow this buffer?
      ... >> Anyone tried that sort of stuff in fstab? ... because this fails to work on the commandline: ... I tried tons of different ways, never could get mount to do that, so I ... But what I did discover is that if I mount the same nfs resource ...
      (freebsd-stable)
    • RE: Machine not Booting - Continued
      ... The fstab is not to blame for this issue as i have just run mkraid /dev/md0 ... and then a mount -a and the area mounted straight away. ... it has no proper file system to mount. ...
      (RedHat)
    • Re: How to set /etc/fstab again after system has started
      ... That is the incorrect statement. ... With an appropriate entry in fstab, it takes very little, ... but without it the mount command needs more information. ... The previous poster went off on a tangent, ...
      (comp.os.linux.misc)