lkml.org 
[lkml]   [2004]   [Jul]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: O_DIRECT
    On Tue, 20 Jul 2004 10:27:57 -0700
    Shesha Sreenivasamurthy <shesha@inostor.com> wrote:

    Hi Shesha,

    > I am having trouble with O_DIRECT. Trying to read or write from a block
    > device partition.
    >
    > 1. Can O_DIRECT be used on a plain block device partition say
    > "/dev/sda11" without having a filesystem on it.

    yes.

    > 2. If no file system is created then what should be the softblock size.
    > I am using the IOCTL "BLKBSZGET". Is this correct?

    yes.

    > 3. Can we use SEEK_END with O_DIRECT on a partition without filesystem.

    yes.

    I'm using these exact things in an application.

    Note that with 2.4 kernels the "granularity" you can use for offset
    and r/w size is the softblock size (*). For 2.6 the requirements are
    much more relaxed: it's the device blocksize (typically 512 byte).

    (*): actually one of offset or r/w size has a smaller minimum if
    I remember correctly. Don't remember which one. But if you assume
    the softblock size as a minimum for both you're allways safe.

    greetings,
    Rob van Nieuwkerk
    -
    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: 2005-03-22 14:04    [W:0.020 / U:31.072 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site