lkml.org 
[lkml]   [2010]   [Sep]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 0/5] hybrid union filesystem prototype
    On Thu, 2 Sep 2010 15:15:37 +0200 (CEST)
    Jan Engelhardt <jengelh@medozas.de> wrote:

    >
    > On Monday 2010-08-30 12:18, Miklos Szeredi wrote:
    > >
    > >> My comment about set-theory unions being commutative set me thinking. I
    > >> really don't think "union" is the right name for this thing. There is
    > >> nothing about it which really fits that proper definition of a union.
    > >
    > >We could call it overlayfs. People learn new names quickly :)
    >
    > There is a much larger issue that you should be very well aware about —
    >
    > "The name wanted to be a clever acronym for "Filesystem in
    > USErspace", but it turned out to be an unfortunate choice. The author
    > has since vowed never to name a project after a common term, not even
    > anything found more than a handful of times on Google."
    >
    > overlayfs already exists. Right next to fuse on sourceforge...

    lol


    No, I mean it. "Linux Over-Lays". :-)

    >
    >
    > Oh and I what I like to see is support for multiple readonly branches :)

    I think we very nearly have that, assuming I understand your requirement
    correctly.
    The lower filesystem can itself be an overlay, providing it is mounted
    read-only.

    So if /mnt/ro1 /mnt/ro2 /mnt/ro3 are all read-only branches then

    mount -o ro,lowerdir=/mnt/ro1,upperdir=/mnt/ro2 meaninglessstring /mnt/ov1
    mount -o ro,lowerdir=/mnt/ov1,upperdir=/mnt/ro3 meaninglessstring /mnt/ov2
    mount -o lowerdir=/mnt/ov2,upperdir=/mnt/rw ignoreme /mnt/overlay

    and /mnt/overlay will be the combination of 3 read-only filesystems and one
    writable one.
    (this doesn't work with the code as-is, but it is really just a few bug-fixes
    away).

    NeilBrown
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2010-09-02 15:35    [W:0.023 / U:0.760 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site