[Libguestfs] [PATCH nbdkit 0/9] cache: Implement cache-max-size and method of reclaiming space from the cache.

This patch series enhances the cache filter in a few ways, primarily adding a "cache-on-read" feature (similar to qemu's copyonread); and adding the ability to limit the cache size and the antecedent of that which is having a method to reclaim cache blocks. As the cache is stored as a sparse temporary file, reclaiming cache blocks simply means punching holes in the temporary file. The tricky bit is working out where to punch the holes to avoid reclaiming recently/frequently used blocks. I believe the status of the patch series is: [1/9] cache: Rename blk_writeback function. [2/9] cache: Add cache-on-read mode. [3/9] common/bitmap: Include <nbdkit-plugin.h>. [4/9] cache: Split out the block/bitmap code into - All of the above patches are pretty uncontroversial and ready for review and upstreaming. [5/9] cache: Allow this filter to serve requests in - Probably needs more testing, but should be OK too. [6/9] common/bitmap: Add bitmap_next function and tests. [7/9] common/bitmap: Add bitmap_clear function. [8/9] cache: Implement LRU structure. [9/9] cache: Implement cache-max-size and method of - Needs much better testing, and maybe even review of the design. Rich.