Re: dd PATCH: add conv=direct

[Andrew Morton]

Andy Isaacson <address@hidden> wrote:
>
> On modern Linux, apparently the correct way to bypass the buffer cache
> when writing to a block device is to open the block device with
> O_DIRECT.  This enables, for example, the user to more easily force a
> reallocation of a single sector of an IDE disk with a media error
> (without overwriting anything but the 1k "sector pair" containing the
> error).  dd(1) is convenient for this purpose, but is lacking a method
> to force O_DIRECT.  The enclosed patch adds a "conv=direct" flag to
> enable this usage.

This would be rather nice to have.  You'll need to ensure that the data
is page-aligned in memory.

While you're there, please add an fsync-before-closing option.