On Thu, Apr 13, 2017 at 02:30:06PM -0400, Brian Foster wrote: > I'm not quite following why this retry is unsafe as noted in the patch > title.. do you mean "unnecessary?" AFAICT, the firstblock == NULLFSBLOCK > case means we can issue this first allocation from any AG. Yes. > If no AG can > allocate a block while satisfying minleft, then we can still safely > allocate from any AG provided any subsequent allocations occur in > increasing AG order (i.e., by setting dop_low), right? Yes. But minleft is set exactly because we require this number of blocks to be left after the current allocation. If we could only allocate the current allocation, but not satisfy minleft we risk shutting the file system during subsequent allocations instead of just returning ENOSPC now. > Also, if this is unnecessary, what exactly verifies that all of the > reserved blocks are available within the same AG? xfs_alloc_space_available verifies that ->total blocks are available in the current AG. Callers of the allocator need to set it to the correct value currently, although I have more xfs_bmapi changes in the pipe to get this right automatically - but those aren't 4.12 material. -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
