On Thu, 30.09.10 21:59, Kay Sievers (kay.sievers@xxxxxxxx) wrote:
> > So my question is, is this what we want? Do I just need to quit bitching and
> > make it work? Or am I doing something wrong? This is a completely new area for
> > me so I'm just looking around at what md/dm does and trying to mirror it for my
> > own uses, if thats not what I should be doing please tell me, otherwise this
> > seems like alot of work for a very shitty solution to our problem. Thanks,
>
> Yeah, that matches what I was experiencing when thinking about the
> options. Making a btrfs mount a fake blockdev of zero size seems like
> a pretty weird hack, just get some 'dead' directories in sysfs. A
> btrfs mount is just not a raw blockdev, and should probably not
> pretend to be one.
>
> I guess a statfs()-like call from the filesystem side and not the
> block side, which can put out such information in some generic way,
> would better fit here.
Note that for my particular usecase it would even suffice to have two
flags in struct statfs or struct statvfs that encode whether there's a at
least one SSD in the fs, resp. at least one rotating disk in the fs.
if (statvfs.f_flag & ST_SSD)
printf("FS contains at least one SSD disk");
if (statvfs.f_flag & ST_ROTATING)
printf("FS contains at least one rotating disk");
Lennart
--
Lennart Poettering - Red Hat, Inc.
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