Linus Torvalds 8912c2fd58 Merge tag 'for-6.20-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
 "User visible changes, feature updates:

   - when using block size > page size, enable direct IO

   - fallback to buffered IO if the data profile has duplication,
     workaround to avoid checksum mismatches on block group profiles
     with redundancy, real direct IO is possible on single or RAID0

   - redo export of zoned statistics, moved from sysfs to
     /proc/pid/mountstats due to size limitations of the former

  Experimental features:

   - remove offload checksum tunable, intended to find best way to do it
     but since we've switched to offload to thread for everything we
     don't need it anymore

   - initial support for remap-tree feature, a translation layer of
     logical block addresses that allow changes without moving/rewriting
     blocks to do eg. relocation, or other changes that require COW

  Notable fixes:

   - automatic removal of accidentally leftover chunks when
     free-space-tree is enabled since mkfs.btrfs v6.16.1

   - zoned mode:
      - do not try to append to conventional zones when RAID is mixing
        zoned and conventional drives
      - fixup write pointers when mixing zoned and conventional on
        DUP/RAID* profiles

   - when using squota, relax deletion rules for qgroups with 0 members
     to allow easier recovery from accounting bugs, also add more checks
     to detect bad accounting

   - fix periodic reclaim scanning, properly check boundary conditions
     not to trigger it unexpectedly or miss the time to run it

   - trim:
      - continue after first error
      - change reporting to the first detected error
      - add more cancellation points
      - reduce contention of big device lock that can block other
        operations when there's lots of trimmed space

   - when chunk allocation is forced (needs experimental build) fix
     transaction abort when unexpected space layout is detected

  Core:

   - switch to crypto library API for checksumming, removed module
     dependencies, pointer indirections, etc.

   - error handling improvements

   - adjust how and where transaction commit or abort are done and are
     maybe not necessary

   - minor compression optimization to skip single block ranges

   - improve how compression folios are handled

   - new and updated selftests

   - cleanups, refactoring:
      - auto-freeing and other automatic variable cleanup conversion
      - structure size optimizations
      - condition annotations"

* tag 'for-6.20-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (137 commits)
  btrfs: get rid of compressed_bio::compressed_folios[]
  btrfs: get rid of compressed_folios[] usage for encoded writes
  btrfs: get rid of compressed_folios[] usage for compressed read
  btrfs: remove the old btrfs_compress_folios() infrastructure
  btrfs: switch to btrfs_compress_bio() interface for compressed writes
  btrfs: introduce btrfs_compress_bio() helper
  btrfs: zlib: introduce zlib_compress_bio() helper
  btrfs: zstd: introduce zstd_compress_bio() helper
  btrfs: lzo: introduce lzo_compress_bio() helper
  btrfs: zoned: factor out the zone loading part into a testable function
  btrfs: add cleanup function for btrfs_free_chunk_map
  btrfs: tests: add cleanup functions for test specific functions
  btrfs: raid56: fix memory leak of btrfs_raid_bio::stripe_uptodate_bitmap
  btrfs: tests: add unit tests for pending extent walking functions
  btrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation
  btrfs: fix transaction commit blocking during trim of unallocated space
  btrfs: handle user interrupt properly in btrfs_trim_fs()
  btrfs: preserve first error in btrfs_trim_fs()
  btrfs: continue trimming remaining devices on failure
  btrfs: do not BUG_ON() in btrfs_remove_block_group()
  ...
2026-02-09 15:45:21 -08:00
2025-02-19 14:53:27 -07:00
2026-02-08 13:03:27 -08:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst



Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst
S
Description
No description provided
Readme
5.7 GiB
Languages
C 96.9%
Assembly 0.9%
Rust 0.6%
Shell 0.6%
Python 0.5%
Other 0.3%