On Wed, Oct 19, 2016 at 10:08:23AM -0700, Divya Indi wrote: > On 10/17/2016 06:42 PM, Qu Wenruo wrote: > > At 10/18/2016 08:35 AM, Divya Indi wrote: > >> Add new subcommand to btrfs inspect-internal > >> > >> btrfs inspect-internal balance_check <path> > >> Checks whether 'btrfs balance' can help creating more space (Only > >> considers data block groups). > > > > I didn't think it's good to add a new subcommand just for that. > > > > Why not output such relocation sugguestion for you previous bg-analyze > > subcommand? > > (It's better to make it a parameter to trigger such output) > Or maybe as an option to btrfs balance start? > Eg: btrfs balance start --check-only <path>
I tend to agree with this approach. The usecase, with some random sample balance options: $ btrfs balance start --analyze -dusage=10 -musage=5 /path returns if the command would be able to make any progress according to the given filters and then $ btrfs balance start -dusage=10 -musage=5 /path would actually do that. This is inherently racy, as the analysis will happen in userspace and the filesystem block group layout could change in the meantime. This also implies that the filters are implemented in the userspace, duplicating the kernel code. This is not neccesarily bad, as this would work even on older kernels (with new progs), compared to a new analysis mode of balance implemented in kernel. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
