On Sat, Aug 10, 2019 at 12:33:43AM -0700, Christoph Hellwig wrote: > > On Fri, Aug 09, 2019 at 02:18:29PM -0400, Theodore Ts'o wrote: > > For debugging reasons, it's useful to know the contents of the extent > > cache. Since the extent cache contains much of what is in the fiemap > > ioctl, extend the fiemap interface to return this information via some > > ext4-specific flags. > > Nak. No weird fs specific fiemap flags that aren't even in the uapi > header. Please provide your own debug only interface. I can understand why you don't like this from the principle of the thing. I'll create my own ioctl, and make a copy of ioctl_fiemap() into ext4 and modify it for my needs. I was trying to avoid needing to do that, since there is plenty of space in the fiemap flags to carve out space for file-specific specific flags, and avoiding making extra copies of code for the purposes of reuse weighed more heavily than "no fs-specific fiemap flags". - Ted
