Re: [PATCH 008 of 8] md/bitmap: Change md/bitmap file handling to use bmap to file blocks.

Andrew Morton
2006-05-13T15:45:15Z

Paul Clements <paul.clements@steeleye.com> wrote:
>
> Andrew Morton wrote:
>
> > The loss of pagecache coherency seems sad. I assume there's never a
> > requirement for userspace to read this file.
>
> Actually, there is. mdadm reads the bitmap file, so that would be
> broken. Also, it's just useful for a user to be able to read the bitmap
> (od -x, or similar) to figure out approximately how much more he's got
> to resync to get an array in-sync. Other than reading the bitmap file, I
> don't know of any way to determine that.

Read it with O_DIRECT :(