Re: squashfs seems nfs-incompatible

From: Jan Engelhardt (
Date: 08/05/05

  • Next message: Davy Durham: "/proc question"
    Date:	Fri, 5 Aug 2005 08:08:07 +0200 (MEST)
    To: Phillip Lougher <>


    >> I found out that you cannot mount an exported squash fs. The exports(5) fsid=
    >> parameter does not help it [like it did with unionfs].
    >The exports(5) man page says fsid=num is necessary for filesystems on
    >non-block devices - I don't know whether this includes loopback
    >filesystems. Have you tried exporting a Squashfs filesystem mounted
    >on a real block device?

    Loopback is a real block device, and no, fsid= does not help it. I have talked
    with the unionfs people, because it works for them. After a short flash of
    idea and comparison, it turns out that squashfs is missing
    sb->s_export->get_parent (the only requirement as it seems). Includes that you
    have sb->s_export non-null, of course. sb->s_export can be set within

    >I've never tried to export a Squashfs filesystem, and so I don't know
    >if it works. If it doesn't, I would say it is because Squashfs (like
    >Cramfs) doesn't store correct nlink information for directories.
    >The next release does store nlink information, has support for > 4GB
    >files/filesystems, and other nice improvements. I'm hoping to release
    >an alpha release soon.

    FTR, I currently cheated by using
    `mount -t unionfs -o dirs=/squash=ro none /squash` to get the export working.

    Jan Engelhardt

    | Alphagate Systems,
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

  • Next message: Davy Durham: "/proc question"

    Relevant Pages

    • Re: [PATCH][2/2] SquashFS
      ... Squashfs 1.x filesystems were the previous file format. ... Is this purely endian conversion or do ... For efficiency Squashfs encodes the location of inode data on disk ...
    • Re: [PATCH][2/2] SquashFS
      ... It would be nice not to bring in legacy code. ... > Squashfs 1.x filesystems were the previous file format. ... > support into the kernel is meant to answer. ...
    • [announce] Squashfs 3.2 released
      ... NFS exporting is now supported, and the kernel code has been hardened against accidently or maliciously corrupted filesystems. ... The new release correctly handles all corrupted filesystems generated by the fsfuzzer tool without oopsing the kernel. ... This in particular fixes the MOKB report raised against Squashfs. ...