lwn.net

LWN.net is a comprehensive source of news and opinions from
and about the Linux community. This is the main LWN.net feed,
listing all articles which are posted to the site front page.
URL: https://lwn.net
업데이트: 2시간 3분 지남
[$] LWN.net Weekly Edition for May 19, 2022
The LWN.net Weekly Edition for May 19, 2022 is available.
LWN is hiring
LWN does its best to provide comprehensive coverage of the free-software
development community, but there is far more going on than our small staff
can handle. When expressed that way, this problem suggests an obvious
solution: make the staff bigger. Thus, LWN is looking to hire a
writer/editor.
[$] Unique identifiers for NFS
In a combined filesystem and storage session at the
2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM), Chuck Lever
wanted to discuss the need for a permanent, globally unique ID for network
filesystems. He was joined by Hannes Reinecke who has worked on the
problem for NVMe storage devices; Lever said something along those
lines is needed for NFSv4. He was hoping to find a solution during the
session, though it would seem that the solution may lie in user space—and
documentation.
openSUSE Leap Micro 5.2 released
OpenSUSE Leap Micro is a new distribution, described as "an
ultra-reliable, lightweight operating system built for containerized and
virtualized workloads". The initial release (5.2) is
now available. More information can be found in the
5.2 release notes.
[$] Snapshots, inodes, and filesystem identifiers
A longstanding problem with Btrfs subvolumes
and duplicate inode numbers was the topic of a late-breaking filesystem session
at the
2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM). The problem had
cropped up in the bcachefs session but
Josef Bacik deferred that discussion to this just-created session, which he led. The
problem is not limited to Btrfs, though, since filesystem snapshots for
other filesystems can
have similar kinds of problems.
Yet another set of stable kernel updates
Security updates for Wednesday
Security updates have been issued by Debian (elog, needrestart, openssl, and waitress), Fedora (curl, libxml2, slurm, and vim), Scientific Linux (zlib), SUSE (e2fsprogs, nodejs10, php72, and thunderbird), and Ubuntu (apport, clamav, needrestart, and pcre3).
[$] Bringing bcachefs to the mainline
Bcachefs is a longstanding out-of-tree
filesystem that grew out of the bcache caching
layer that has been in the kernel for nearly ten years. Based on a
session led by Kent Overstreet at the
2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM), though, it would
seem that bcachefs is likely to be heading upstream soon. He intends to
start the process toward mainline inclusion over the next six months or so.
[$] Sharing page tables with mshare()
The Linux kernel allows processes to share pages in memory, but the page
tables used to control that sharing are not, themselves, shared; as a
result, processes sharing memory maintain duplicate copies of the
page-table data. Normally this duplication imposes little overhead, but
there are situations where it can hurt. At the 2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM), Khaled Aziz
(remotely) and Matthew Wilcox led a session to discuss a proposed mechanism
to allow those page tables to be shared between cooperating processes.
Inkscape 1.2 released
Version 1.2 of the
Inkscape drawing tool has been released. New features include multi-page
support, editable markers, the ability to flow text around shapes, and
more; see the
release notes for details.
Security updates for Tuesday
Security updates have been issued by Debian (cifs-utils, ffmpeg, libxml2, and vim), Fedora (rsyslog), Mageia (chromium-browser-stable), SUSE (chromium, containerd, docker, e2fsprogs, gzip, jackson-databind, jackson-dataformats-binary, jackson-annotations, jackson-bom, jackson-core, kernel, nodejs8, openldap2, pidgin, podofo, slurm, and tiff), and Ubuntu (clamav, containerd, libxml2, and openldap).
[$] Dynamically allocated pseudo-filesystems
It is perhaps unusual to have a kernel tracing developer leading a
filesystem session, Steven Rostedt said, at the beginning of such a session at the
2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM). But he was doing
so to
try to find a good way to dynamically allocate kernel data structures
for some of the pseudo-filesystems, such as sysfs, debugfs, and tracefs,
in the kernel.
Avoiding static allocations would save memory, especially on systems
that are not actually using any of the files in those filesystems.
SFC v. Vizio remanded back to California state courts
Software Freedom Conservancy (SFC)
has announced
that it succeeded with its motion in US Federal Court to send the case back
to California, where it was originally filed. The suit was filed
in October 2021 by SFC, as an owner of Vizio televisions, to get
the company to comply with the GPL on some of the code in the TVs. Back in November, Vizio had
asked to move the
case to Federal Court, because the GPL is only a copyright license
(which is a dispute handled at the Federal level) and not a contract (that
could be adjudicated in state court). Friday's ruling disagreed with that premise:
The May 13 ruling by the Honorable Josephine L. Staton stated that the
claim from Software Freedom Conservancy succeeded in the "extra element
test" and was not preempted by copyright claims, and the court finds "that
the enforcement of 'an additional contractual promise separate and distinct
from any rights provided by the copyright laws' amounts to an 'extra
element,' and therefore, SFC's claims are not preempted."
"The ruling is a watershed moment in the history of copyleft licensing. This ruling shows that the GPL agreements function both as copyright licenses and as contractual agreements," says Karen M. Sandler, executive director of Software Freedom Conservancy. Sandler noted that many in the Free and Open Source Software (FOSS) legal community argue incorrectly that the GPL and other copyleft licenses only function as copyright licenses.
[$] The netfslib helper library
A new helper library for network filesystems, called netfslib, was the subject
of a filesystem session at the
2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM). David Howells
developed
netfslib, which was merged for 5.13 a year ago, and led the session.
Some filesystems, like AFS and Ceph, are already using some of the services
that netfslib provides, while others are starting to look into it.
Security updates for Monday
Security updates have been issued by CentOS (gzip, java-1.8.0-openjdk, java-11-openjdk, and zlib), Debian (adminer, htmldoc, imagemagick, libgoogle-gson-java, lrzip, openjdk-8, openssl, and ruby-nokogiri), Fedora (ecdsautils, et, libxml2, podman, and supertux), Mageia (cairo, clamav, curl, fish, freetype2, golang-github-prometheus-client, python-django-registration, python-nbxmpp, python-waitress, and xmlrpc-c), Red Hat (pcs), SUSE (curl, kernel, pidgin, and webkit2gtk3), and Ubuntu (tiff).
Kernel prepatch 5.18-rc7
The 5.18-rc7 kernel prepatch has been
released for testing. Linus says: "So things continue to be fairly
calm, and as such this is likely the last rc before 5.18 unless something
bad happens next week".
Sunday's stable kernels
[$] Proactive reclaim for tiered memory and more
Memory reclaim in Linux is largely a reactive practice; the kernel tries to
find memory it can repurpose in response to the amount of free memory
falling too low. Developers have often wondered if a proactive reclaim
mechanism might lead to better performance, for some workloads at least,
and optimal use of tiered-memory systems will likely require more active
reclamation of memory as well. At the 2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM), Davidlohr Bueso
led a brief session on the topic.
[$] CXL 1: Management and tiering
Compute Express
Link (CXL) is an upcoming memory technology that is clearly on the
minds of Linux memory-management developers; there were five sessions
dedicated to the topic at the 2022 Linux Storage,
Filesystem, Memory-management and BPF Summit (LSFMM). The first three
sessions, on May 3, covered various aspects of memory management in the
presence of CXL. It seems that
CXL may bring some welcome capabilities, especially for cloud-service
providers, but that will come at the cost of some headaches on the
kernel-development side.
Security updates for Friday
Security updates have been issued by Debian (chromium, postgresql-11, postgresql-13, and waitress), Fedora (curl, java-1.8.0-openjdk-aarch32, keylime, and pcre2), Oracle (gzip and zlib), Red Hat (subversion:1.10), SUSE (clamav, documentation-suse-openstack-cloud, kibana, openstack-keystone, openstack-monasca-notification, e2fsprogs, gzip, and kernel), and Ubuntu (libvorbis and rsyslog).