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Christian Brauner 7e463614c9
Merge patch series "vfs: require filesystems to explicitly opt-in to lease support"
Jeff Layton <jlayton@kernel.org> says:

Yesterday, I sent patches to fix how directory delegation support is
handled on filesystems where the should be disabled [1]. That set is
appropriate for v6.19. For v7.0, I want to make lease support be more
opt-in, rather than opt-out:

For historical reasons, when ->setlease() file_operation is set to NULL,
the default is to use the kernel-internal lease implementation. This
means that if you want to disable them, you need to explicitly set the
->setlease() file_operation to simple_nosetlease() or the equivalent.

This has caused a number of problems over the years as some filesystems
have inadvertantly allowed leases to be acquired simply by having left
it set to NULL. It would be better if filesystems had to opt-in to lease
support, particularly with the advent of directory delegations.

This series has sets the ->setlease() operation in a pile of existing
local filesystems to generic_setlease() and then changes
kernel_setlease() to return -EINVAL when the setlease() operation is not
set.

With this change, new filesystems will need to explicitly set the
->setlease() operations in order to provide lease and delegation
support.

I mainly focused on filesystems that are NFS exportable, since NFS and
SMB are the main users of file leases, and they tend to end up exporting
the same filesystem types. Let me know if I've missed any.

[1]: https://lore.kernel.org/linux-fsdevel/20260107-setlease-6-19-v1-0-85f034abcc57@kernel.org/

* patches from https://patch.msgid.link/20260108-setlease-6-20-v1-0-ea4dec9b67fa@kernel.org: (24 commits)
  fs: remove simple_nosetlease()
  filelock: default to returning -EINVAL when ->setlease operation is NULL
  xfs: add setlease file operation
  ufs: add setlease file operation
  udf: add setlease file operation
  tmpfs: add setlease file operation
  squashfs: add setlease file operation
  overlayfs: add setlease file operation
  orangefs: add setlease file operation
  ocfs2: add setlease file operation
  ntfs3: add setlease file operation
  nilfs2: add setlease file operation
  jfs: add setlease file operation
  jffs2: add setlease file operation
  gfs2: add a setlease file operation
  fat: add setlease file operation
  f2fs: add setlease file operation
  exfat: add setlease file operation
  ext4: add setlease file operation
  ext2: add setlease file operation
  ...

Link: https://patch.msgid.link/20260108-setlease-6-20-v1-0-ea4dec9b67fa@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
History 2026-01-12 10:55:54 +01:00
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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