lkml.org 
[lkml]   [2012]   [Aug]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [overlayfs/port] overlayfs: v13 port attempt to kernel 3.5
    Date

    Sedat Dilek:
    > The other part to run a Linux live-system is a "Union FileSystem" -
    > this part is missing (speaking of upstream).
    >
    > Since years AUFS seems to be the choice #1 in a lot of distros to
    > workaround the problem.
    > NOTE: AUFS was rejected from upstream (to say not accepted).

    Exactly.
    The reason was that linux rejects all union-type filesystems but
    UnionMount (which is union-type mount).
    Later, the development of UnionMount seems to be almost stopped. The
    essential design of overlayfs is based upon UnionMount, and I have
    pointed out several issues such as
    - for users, the inode number may change silently. eg. copy-up.
    - hardlinks may break by copy-up.
    - read(2) may get an obsoleted filedata (fstat(2) for metadata too).
    - fcntl(F_SETLK) may be broken by copy-up.
    - unnecessary copy-up may happen, for example mmap(MAP_PRIVATE) after
    open(O_RDWR).
    - Later I noticed one more thing. /proc/PID/{fd/,exe} may not work
    correctly for overlayfs ...
    - etc...
    They are called "unPOSIXy behavior", and unforunately many of them are
    NOT seem to be addressed in recent patches either.

    Also I have posted
    If the development of UnionMount is really stopped, then I'd ask people
    to consider merging aufs as well as overlayfs.
    but I am not sure whether LKML people are still waiting for UnionMount
    and rejecting aufs.


    J. R. Okajima


    \
     
     \ /
      Last update: 2012-08-20 13:21    [W:5.042 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site