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Chao Yu 0a1703eba2 f2fs: fix to avoid pinfile fragment on fragment:{block, segment} mode
pinfile fallocate() conflicts w/ mode=fragment:{block,segment} mount option,
result in fragment blocks in pinfile, it violate semantics of pinfile
introduced in commit f5a53edcf0 ("f2fs: support aligned pinned file").

mkfs.f2fs -f /dev/vdb
mount -t f2fs -o mode=fragment:block /dev/vdb /mnt/f2fs/
dd if=/dev/zero of=/mnt/f2fs/file bs=1M count=3900
sync
touch /mnt/f2fs/pinfile
f2fs_io pinfile set /mnt/f2fs/pinfile
f2fs_io fallocate 0 0 $((1024*1024*16)) /mnt/f2fs/pinfile
sync
f2fs_io fiemap 0 $((1024*1024*16)) /mnt/f2fs/pinfile

[Before]
fallocate failed: No space left on device
Fiemap: offset = 0 len = 16777216
        logical addr.    physical addr.   length           flags
0       0000000000000000 00000000d7200000 0000000000004000 00001000
1       0000000000004000 00000000d7207000 0000000000001000 00001000
2       0000000000005000 00000000d720c000 0000000000002000 00001000
3       0000000000007000 00000000d7211000 0000000000001000 00001000
4       0000000000008000 00000000d7214000 0000000000001000 00001000
5       0000000000009000 00000000d7218000 0000000000001000 00001000
6       000000000000a000 00000000d721d000 0000000000001000 00001000
7       000000000000b000 00000000d721f000 0000000000004000 00001000
...
96      00000000000f1000 00000000d73e9000 0000000000004000 00001000
97      00000000000f5000 00000000d73f1000 0000000000003000 00001000
98      00000000000f8000 00000000d73f5000 0000000000004000 00001000
99      00000000000fc000 00000000d73fa000 0000000000001000 00001000
100     00000000000fd000 00000000d73ff000 0000000000001000 00001001

[After]
fallocated a file: i_size=16777216, i_blocks=32808
Fiemap: offset = 0 len = 16777216
        logical addr.    physical addr.   length           flags
0       0000000000000000 0000000018a00000 0000000000400000 00001000
1       0000000000400000 0000000019000000 0000000000400000 00001000
2       0000000000800000 0000000032400000 0000000000200000 00001000
3       0000000000a00000 0000000038000000 0000000000200000 00001000
4       0000000000c00000 0000000039c00000 0000000000200000 00001000
5       0000000000e00000 0000000044c00000 0000000000200000 00001001

Let's ignore mode=fragment:{block,segment} mount option while fallocate()
on pinfile.

Fixes: 6691d940b0 ("f2fs: introduce fragment allocation mode mount option")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
History 2026-08-17 21:43:38 +00:00
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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
* AI Coding Assistant - LLMs and AI-powered development tools


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

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


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=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
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* MAINTAINERS file: Lists subsystem maintainers and mailing lists
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