lkml.org 
[lkml]   [2007]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: If not readdir() then what?
    From
    Date
    On Wed, 2007-04-11 at 07:37 +1000, Neil Brown wrote:
    > On Tuesday April 10, trond.myklebust@fys.uio.no wrote:
    > > On Wed, 2007-04-11 at 07:12 +1000, Neil Brown wrote:
    > > >
    > > > Is there something that makes that interface problematic?
    > >
    > > File deletions...
    >
    > How are they a problem ?
    >
    > There are only two ways to organise a directory.
    > 1/ Unsorted linear list of entries in which no repacking is ever done.
    > 2/ Some data structure using an ordered search key that is based on
    > the filename (e.g. a B-tree with a search key that is a hash of the
    > filename).
    >
    > In the first case, you just use a fixed opaque cookie for location in
    > a directory.
    > In the second you use the filename. If the file has been deleted,
    > that shouldn't stop you finding the place where it would have been in
    > the overall sort order.

    I beg to differ. RAMFS is an instance of a filesystem which uses an
    unsorted linear list of entries which is automatically repacked when you
    delete a file.

    You may also have filesystems which are only partially sorted. The
    dcache is for instance organised as a hashtable with multiple entries
    per bucket...

    Cheers
    Trond

    -
    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: 2007-04-11 00:03    [W:0.023 / U:1.528 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site