[lkml]   [2000]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: NFS locking bug -- limited mtime resolution means nfs_lock() does not provide coherency guarantee
    Theodore Y. Ts'o wrote:
    > Date: Thu, 14 Sep 2000 15:09:35 +0200 (CEST)
    > From: Trond Myklebust <>
    > Would it perhaps make sense to use one of these last 'free' fields
    > as a pointer to an 'inode entension'?
    > If you still want ext2fs to be able to accommodate new projects and
    > ideas, then it seems that being able to extend the inode is a
    > desirable feature, but perhaps this overlaps with the apparent plans
    > for adding resource forks?
    > For stuff that's not commonly used, perhaps. The problem is that you
    > take a speed hit when you have to seek somewhere else to get at the
    > inode extension. So for something which is going to have to be
    > referenced for every stat() or getattr() operation, there are a real
    > performance issues with doing something like that.

    The "right" way to do this is to have a "this spot is in use, but you
    don't understand it" indication for an inode (*). The "expansion ptr"
    can then normally point to the directly following inode, but also
    somewhere completely different.

    So a "new" system would allocate a new inode in the directly following
    spot. But when a "new" system would need the extension part on an old
    filesystem, it would allocate the nearest inode and point the
    extension ptr there.


    (*) Actually the kernel only needs the "it's in use" part. fsck needs
    to know what it means or to properly ignore it....

    ** ** ** +31-15-2137555 **
    *-- BitWizard writes Linux device drivers for any device you may have! --*
    * Common sense is the collection of *
    ****** prejudices acquired by age eighteen. -- Albert Einstein ********
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 12:38    [W:0.032 / U:6.768 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site