On Tue, Oct 22, 2013 at 02:39:06PM -0400, Jeff Mahoney wrote:
> On 10/22/13 2:26 PM, Josef Bacik wrote:
> > On Mon, Oct 21, 2013 at 05:19:40PM -0400, Jeff Mahoney wrote:
> >> This patchset implements the stubbed-out sysfs interface for btrfs. Or
> >> at least begins to do so.
> >>
> >> We publish:
> >> - Features supported by the file system implementation
> >> - Features enabled on the file system, including features unknown to
> >> the implemenation. These attributes can also be used to enable or
> >> disable features at runtime, subjecting to a safety mask.
> >> - Uses the attribute names to print feature names when declining to
> >> mount a file system.
> >> - The allocation data: global metadata reservation size and reserved,
> >> space_infos, and sums of the block groups total and used bytes.
> >> - Device membership via links to the block devices.
> >> - FS label, which is writeable.
> >>
> >> - I've also added matching ioctls for some of the functionality here so
> >> that btrfsprogs can use the information without jumping through hoops
> >> to read/parse the sysfs files. There are ioctls to query the supported
> >> features and to query/set features on a particular file system. There's
> >> also one to export the size of the global metadata reservation. I have
> >> a patch for btrfs-progs that uses this to print useful info in 'btrfs
> >> fi df' output.
> >>
> >> Ultimately, the tree structure looks like the following, under /sys/fs/btrfs.
> >> This is from a test file system, using two devices in raid1. You'll notice
> >> the 'single' and 'raid1' directories under the {data,metadata,system} dirs.
> >> The raid profiles are created and removed as the first/last block group
> >> of a certain profile is added and removed.
> >>
> >
> > I'm not pulling in patches that add new functionality without an accompanying
> > xfstest so that we're not merging features without a way to test to make sure
>
> Sure, that's reasonable.
>
> > they are working properly, this applies to the global metadata reservation ioctl
> > as well. Thanks,
>
> What would a test look like for that? It's information that isn't
> currently available anywhere in userspace and isn't represented in the
> file system itself.
>
I thought it did more than what it did, but still I'd like a sanity check, so
maybe mkfs and mount a scratch dev and make sure it comes back with > 0 and less
than say 10mb? Thanks,
Josef
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