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 sureSure, 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. -Jeff -- Jeff Mahoney SUSE Labs
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