Episode Details

OpenBSD 6.3 and DragonflyBSD 5.2 are released, bug fix for disappearing files in OpenZFS on Linux (and only Linux), understanding the FreeBSD CPU scheduler, NetBSD on RPI3, thoughts on being a committer for 20 years, and 5 reasons to use FreeBSD in 2018.

Headlines

OpenBSD 6.3 released

• Punctual as ever, OpenBSD 6.3 has been releases with the following features/changes:

  Improved HW support, including: SMP support on OpenBSD/arm64 platforms vmm/vmd improvements: IEEE 802.11 wireless stack improvements Generic network stack improvements Installer improvements Routing daemons and other userland network improvements Security improvements dhclient(8) improvements Assorted improvements OpenSMTPD 6.0.4 OpenSSH 7.7 LibreSSL 2.7.2

DragonFlyBSD 5.2 released

Big-ticket items Meltdown and Spectre mitigation support Meltdown isolation and spectre mitigation support added. Meltdown mitigation is automatically enabled for all Intel cpus. Spectre mitigation must be enabled manually via sysctl if desired, using sysctls machdep.spectremitigation and machdep.meltdownmitigation. HAMMER2 H2 has received a very large number of bug fixes and performance improvements. We can now recommend H2 as the default root filesystem in non-clustered mode. Clustered support is not yet available. ipfw Updates Implement state based "redirect", i.e. without using libalias. ipfw now supports all possible ICMP types. Fix ICMPMAXTYPE assumptions (now 40 as of this release). Improved graphics support The drm/i915 kernel driver has been updated to support Intel Coffeelake GPUs Add 24-bit pixel format support to the EFI frame buffer code. Significantly improve fbio support for the "scfb" XOrg driver. This allows EFI frame buffers to be used by X in situations where we do not otherwise support the GPU. Partly implement the FBIOBLANK ioctl for display powersaving. Syscons waits for drm modesetting at appropriate places, avoiding races. + For more details, check out the “All changes since DragonFly 5.0” section.

ZFS on Linux bug causes files to disappear

• A bug in ZoL 0.7.7 caused 0.7.8 to be released just 3 days after the release
• The bug only impacts Linux, the change that caused the problem was not upstreamed yet, so does not impact ZFS on illumos, FreeBSD, OS X, or Windows
• The bug can cause files being copied into a directory to not be properly linked to the directory, so they will no longer be listed in the contents of the directory
• ZoL developers are working on a tool to allow you to recover the data, since no data was actually lost, the files were just not properly registered as part of the directory
• The bug was introduced in a commit made in February, that attempted to improve performance of datasets created with the case insensitivity option. In an effort to improve performance, they introduced a limit to cap to give up (return ENOSPC) if growing the directory ZAP failed twice.
• The ZAP is the key-value pair data structure that contains metadata for a directory, including a hash table of the files that are in a directory. When a directory has a large number of files, the ZAP is converted to a FatZAP, and additional space may need to be allocated as additional files are added.

  Commit cc63068 caused ENOSPC error when copy a large amount of files between two directories. The reason is that the patch limits zap leaf expansion to 2 retries, and return ENOSPC when failed.

• Finding the root cause of this issue was somewhat hampered by the fact that many people were not able to reproduce the issue. It turns out this was caused