development APIs for used/free blocks information

[Benjamin Wirth]

Hello Dave,

Thanks for your response.

And I apologize, reading back my email I wasn't clear about what I was looking for.

I want to be able to query which blocks are free or used, not just the counts. In EXT I was able to use ext2fs_test_block_bitmap() for that. XFS has a BTree with the free extents ordered by block number which I was hoping to be able to access from user-space, but couldn't find any APIs for it (or the headers containing the structure definitions) in the xfsprogs-devel package. Am I trying to do something impossible here?

Thanks,
Ben

-----Original Message-----
From: Dave Chinner [mailto:david at fromorbit.com] 
Sent: Tuesday, April 26, 2016 6:21 PM
To: Benjamin Wirth
Cc: xfs at oss.sgi.com
Subject: Re: development APIs for used/free blocks information

On Tue, Apr 26, 2016 at 08:51:10PM +0000, Benjamin Wirth wrote:
> Hello,
> 
> I was looking for development APIs for XFS. The contents of 
> xfsprogs-devel seem to only contain a few IOCTL commands, mostly 
> file/inode based operations.
> 
> I need to query free/used blocks of an entire XFS filesystem and was 
> hoping to find some user-space APIs for this.

$ man 2 statvfs

Cheers,

Dave.
--
Dave Chinner
david at fromorbit.com