f2620e9ceb
These two sysctls were added to support UFS softupdates journalling with snapshots. However, the changes to fsck to use them were never committed and there have never been any in-tree uses of these sysctls. More details from Kirk: When journalling got added to soft updates, its journal rollback freed blocks that it thought were no longer in use. But it does not take snapshots into account (i.e., if a snapshot is still using it, then it cannot be freed). So I added the needed logic to fsck by having the free go through the kernel's blkfree code so it could grab blocks that were still needed by snapshots. That is done using the setbufoutput hack. I never got that code working reliably, so it is still sitting in my work directory. Which also explains why you still cannot take snapshots on filesystems running with journalling... In looking over my use of this feature, and in particular the troubles I was having with it, I conclude that it may be better to extract the code from the kernel that handles freeing blocks claimed by snapshots and putting it into fsck directly. My original intent was that it is complex and at the time changing, so only having to maintain it in one place was appealing. But at this point it has not changed in years and the hacks like setinode and setbufoutput to be able to use the kernel code is sufficiently ugly, that I am leaning towards just extracting it. Reviewed by: mckusick MFC after: 1 week Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D24484
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