€•|§Œsphinx.addnodes”Œdocument”“”)”}”(Œ rawsource”Œ”Œchildren”]”(Œ translations”Œ LanguagesNode”“”)”}”(hhh]”(hŒ pending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ refdomain”Œstd”Œreftype”Œdoc”Œ reftarget”Œ6/translations/zh_CN/filesystems/adding-new-filesystems”Œmodname”NŒ classname”NŒ refexplicit”ˆuŒtagname”hhh ubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ6/translations/zh_TW/filesystems/adding-new-filesystems”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ6/translations/it_IT/filesystems/adding-new-filesystems”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ6/translations/ja_JP/filesystems/adding-new-filesystems”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ6/translations/ko_KR/filesystems/adding-new-filesystems”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒPortuguese (Brazilian)”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ6/translations/pt_BR/filesystems/adding-new-filesystems”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒSpanish”…””}”hh–sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ6/translations/sp_SP/filesystems/adding-new-filesystems”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h hhŒ _document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh·sbah}”(h]”h ]”h"]”h$]”h&]”Œ xml:space”Œpreserve”uh1hµhhh²hh³ŒP/var/lib/git/docbuild/linux/Documentation/filesystems/adding-new-filesystems.rst”h´KubhŒtarget”“”)”}”(hŒ.. _adding_new_filesystems:”h]”h}”(h]”h ]”h"]”h$]”h&]”Œrefid”Œadding-new-filesystems”uh1hÈh´Khhh²hh³hÇubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒAdding New Filesystems”h]”hŒAdding New Filesystems”…””}”(hhÝh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÛhhØh²hh³hÇh´KubhŒ paragraph”“”)”}”(hŒXThis document describes what is involved in adding a new filesystem to the Linux kernel.”h]”hŒXThis document describes what is involved in adding a new filesystem to the Linux kernel.”…””}”(hhíh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KhhØh²hubhì)”}”(hXtEvery filesystem merged into the kernel becomes the collective responsibility of the VFS maintainers and the wider filesystem development community. Experience has shown that filesystems which become unmaintained impose a significant and ongoing burden: they are hard or impossible to test, they block infrastructure changes because someone must update or preserve old APIs for code that nobody is actively looking after, and they accumulate unfixed bugs. The requirements and expectations described here are informed by this experience and are intended to ensure that new filesystems enter the kernel on a sustainable footing.”h]”hXtEvery filesystem merged into the kernel becomes the collective responsibility of the VFS maintainers and the wider filesystem development community. Experience has shown that filesystems which become unmaintained impose a significant and ongoing burden: they are hard or impossible to test, they block infrastructure changes because someone must update or preserve old APIs for code that nobody is actively looking after, and they accumulate unfixed bugs. The requirements and expectations described here are informed by this experience and are intended to ensure that new filesystems enter the kernel on a sustainable footing.”…””}”(hhûh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K hhØh²hubh×)”}”(hhh]”(hÜ)”}”(hŒ'Do You Need a New In-Kernel Filesystem?”h]”hŒ'Do You Need a New In-Kernel Filesystem?”…””}”(hj h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÛhj h²hh³hÇh´Kubhì)”}”(hŒpBefore proposing a new in-kernel filesystem, consider whether one of the alternatives might be more appropriate.”h]”hŒpBefore proposing a new in-kernel filesystem, consider whether one of the alternatives might be more appropriate.”…””}”(hjh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´Khj h²hubhŒ block_quote”“”)”}”(hXÈ- If an existing in-kernel filesystem covers the same use case, improving it is generally preferred over adding a new implementation. The kernel community favors incremental improvement over parallel implementations. - If the filesystem serves a niche audience or has a small user base, a FUSE (Filesystem in Userspace) implementation may be a better fit. FUSE filesystems avoid the long-term kernel maintenance commitment and can be developed and released on their own schedule. - If kernel-level performance, reliability, or integration is genuinely required, make the case explicitly. Explain who the users are, what the use case is, and why a FUSE implementation would not be sufficient. ”h]”hŒ bullet_list”“”)”}”(hhh]”(hŒ list_item”“”)”}”(hŒØIf an existing in-kernel filesystem covers the same use case, improving it is generally preferred over adding a new implementation. The kernel community favors incremental improvement over parallel implementations. ”h]”hì)”}”(hŒ×If an existing in-kernel filesystem covers the same use case, improving it is generally preferred over adding a new implementation. The kernel community favors incremental improvement over parallel implementations.”h]”hŒ×If an existing in-kernel filesystem covers the same use case, improving it is generally preferred over adding a new implementation. The kernel community favors incremental improvement over parallel implementations.”…””}”(hj9h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´Khj5ubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hj0ubj4)”}”(hXIf the filesystem serves a niche audience or has a small user base, a FUSE (Filesystem in Userspace) implementation may be a better fit. FUSE filesystems avoid the long-term kernel maintenance commitment and can be developed and released on their own schedule. ”h]”hì)”}”(hXIf the filesystem serves a niche audience or has a small user base, a FUSE (Filesystem in Userspace) implementation may be a better fit. FUSE filesystems avoid the long-term kernel maintenance commitment and can be developed and released on their own schedule.”h]”hXIf the filesystem serves a niche audience or has a small user base, a FUSE (Filesystem in Userspace) implementation may be a better fit. FUSE filesystems avoid the long-term kernel maintenance commitment and can be developed and released on their own schedule.”…””}”(hjQh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K hjMubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hj0ubj4)”}”(hŒÔIf kernel-level performance, reliability, or integration is genuinely required, make the case explicitly. Explain who the users are, what the use case is, and why a FUSE implementation would not be sufficient. ”h]”hì)”}”(hŒÒIf kernel-level performance, reliability, or integration is genuinely required, make the case explicitly. Explain who the users are, what the use case is, and why a FUSE implementation would not be sufficient.”h]”hŒÒIf kernel-level performance, reliability, or integration is genuinely required, make the case explicitly. Explain who the users are, what the use case is, and why a FUSE implementation would not be sufficient.”…””}”(hjih²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K%hjeubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hj0ubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1j.h³hÇh´Khj*ubah}”(h]”h ]”h"]”h$]”h&]”uh1j(h³hÇh´Khj h²hubeh}”(h]”Œ&do-you-need-a-new-in-kernel-filesystem”ah ]”h"]”Œ'do you need a new in-kernel filesystem?”ah$]”h&]”uh1hÖhhØh²hh³hÇh´Kubh×)”}”(hhh]”(hÜ)”}”(hŒTechnical Requirements”h]”hŒTechnical Requirements”…””}”(hj–h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÛhj“h²hh³hÇh´K+ubhì)”}”(hŒÇNew filesystems must use current kernel interfaces and practices. Submitting a filesystem built on outdated APIs creates an unacceptable maintenance debt and is likely to face pushback during review.”h]”hŒÇNew filesystems must use current kernel interfaces and practices. Submitting a filesystem built on outdated APIs creates an unacceptable maintenance debt and is likely to face pushback during review.”…””}”(hj¤h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K-hj“h²hubhŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hXÇUse modern VFS interfaces Do not use interfaces listed in :ref:`Documentation/process/deprecated.rst `. Use folios rather than raw page operations for page cache management and iomap rather than buffer heads for block mapping and I/O. See ``Documentation/filesystems/iomap/index.rst`` for iomap documentation. Block-based filesystems that need functionality not currently provided by iomap should be prepared to explain why adding that functionality to iomap is infeasible, rather than reimplementing their own block mapping layer. Network filesystems should consider using the netfs library (``Documentation/filesystems/netfs_library.rst``), or be prepared to explain why it is not a good fit. ”h]”(hŒterm”“”)”}”(hŒUse modern VFS interfaces”h]”hŒUse modern VFS interfaces”…””}”(hj¿h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´K?hj¹ubhŒ definition”“”)”}”(hhh]”(hì)”}”(hŒYDo not use interfaces listed in :ref:`Documentation/process/deprecated.rst `.”h]”(hŒ Do not use interfaces listed in ”…””}”(hjÒh²hh³Nh´Nubh)”}”(hŒ8:ref:`Documentation/process/deprecated.rst `”h]”hŒinline”“”)”}”(hjÜh]”hŒ$Documentation/process/deprecated.rst”…””}”(hjàh²hh³Nh´Nubah}”(h]”h ]”(Œxref”Œstd”Œstd-ref”eh"]”h$]”h&]”uh1jÞhjÚubah}”(h]”h ]”h"]”h$]”h&]”Œrefdoc”Œ"filesystems/adding-new-filesystems”Œ refdomain”jëŒreftype”Œref”Œ refexplicit”ˆŒrefwarn”ˆŒ reftarget”Œ deprecated”uh1hh³hÇh´K2hjÒubhŒ.”…””}”(hjÒh²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K2hjÏubhì)”}”(hŒÎUse folios rather than raw page operations for page cache management and iomap rather than buffer heads for block mapping and I/O. See ``Documentation/filesystems/iomap/index.rst`` for iomap documentation.”h]”(hŒˆUse folios rather than raw page operations for page cache management and iomap rather than buffer heads for block mapping and I/O. See ”…””}”(hj h²hh³Nh´NubhŒliteral”“”)”}”(hŒ-``Documentation/filesystems/iomap/index.rst``”h]”hŒ)Documentation/filesystems/iomap/index.rst”…””}”(hjh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj ubhŒ for iomap documentation.”…””}”(hj h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K5hjÏubhì)”}”(hŒÝBlock-based filesystems that need functionality not currently provided by iomap should be prepared to explain why adding that functionality to iomap is infeasible, rather than reimplementing their own block mapping layer.”h]”hŒÝBlock-based filesystems that need functionality not currently provided by iomap should be prepared to explain why adding that functionality to iomap is infeasible, rather than reimplementing their own block mapping layer.”…””}”(hj+h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K9hjÏubhì)”}”(hŒ¢Network filesystems should consider using the netfs library (``Documentation/filesystems/netfs_library.rst``), or be prepared to explain why it is not a good fit.”h]”(hŒ=Network filesystems should consider using the netfs library (”…””}”(hj9h²hh³Nh´Nubj)”}”(hŒ/``Documentation/filesystems/netfs_library.rst``”h]”hŒ+Documentation/filesystems/netfs_library.rst”…””}”(hjAh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj9ubhŒ6), or be prepared to explain why it is not a good fit.”…””}”(hj9h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K=hjÏubeh}”(h]”h ]”h"]”h$]”h&]”uh1jÍhj¹ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´K?hj´ubj¸)”}”(hXCProvide userspace utilities A ``mkfs`` tool is expected so that the filesystem can be created and used by testers and users. A ``fsck`` tool is strongly recommended; while not strictly required for every filesystem type, the ability to verify consistency and repair corruption is an important part of a mature filesystem. ”h]”(j¾)”}”(hŒProvide userspace utilities”h]”hŒProvide userspace utilities”…””}”(hjih²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´KFhjeubjÎ)”}”(hhh]”hì)”}”(hX&A ``mkfs`` tool is expected so that the filesystem can be created and used by testers and users. A ``fsck`` tool is strongly recommended; while not strictly required for every filesystem type, the ability to verify consistency and repair corruption is an important part of a mature filesystem.”h]”(hŒA ”…””}”(hjzh²hh³Nh´Nubj)”}”(hŒ``mkfs``”h]”hŒmkfs”…””}”(hj‚h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhjzubhŒZ tool is expected so that the filesystem can be created and used by testers and users. A ”…””}”(hjzh²hh³Nh´Nubj)”}”(hŒ``fsck``”h]”hŒfsck”…””}”(hj”h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhjzubhŒº tool is strongly recommended; while not strictly required for every filesystem type, the ability to verify consistency and repair corruption is an important part of a mature filesystem.”…””}”(hjzh²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KBhjwubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhjeubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´KFhj´h²hubj¸)”}”(hXåBe testable The filesystem must be testable in a meaningful way. The `fstests `_ framework (also known as xfstests) is the standard testing infrastructure for Linux filesystems and its use is highly recommended. At a minimum, there must be a credible and documented way to test the filesystem and detect regressions. When submitting, include a summary of test results indicating which tests pass, fail, or are not applicable. ”h]”(j¾)”}”(hŒ Be testable”h]”hŒ Be testable”…””}”(hj¼h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´KOhj¸ubjÎ)”}”(hhh]”hì)”}”(hXØThe filesystem must be testable in a meaningful way. The `fstests `_ framework (also known as xfstests) is the standard testing infrastructure for Linux filesystems and its use is highly recommended. At a minimum, there must be a credible and documented way to test the filesystem and detect regressions. When submitting, include a summary of test results indicating which tests pass, fail, or are not applicable.”h]”(hŒ:The filesystem must be testable in a meaningful way. The ”…””}”(hjÍh²hh³Nh´NubhŒ reference”“”)”}”(hŒC`fstests `_”h]”hŒfstests”…””}”(hj×h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”Œname”Œfstests”Œrefuri”Œ6https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git”uh1jÕhjÍubhÉ)”}”(hŒ9 ”h]”h}”(h]”Œfstests”ah ]”h"]”Œfstests”ah$]”h&]”Œrefuri”jèuh1hÈŒ referenced”KhjÍubhX[ framework (also known as xfstests) is the standard testing infrastructure for Linux filesystems and its use is highly recommended. At a minimum, there must be a credible and documented way to test the filesystem and detect regressions. When submitting, include a summary of test results indicating which tests pass, fail, or are not applicable.”…””}”(hjÍh²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KIhjÊubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhj¸ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´KOhj´h²hubj¸)”}”(hŒÀProvide documentation A documentation file under ``Documentation/filesystems/`` describing the filesystem, its on-disk format, mount options, and any notable design decisions is recommended. ”h]”(j¾)”}”(hŒProvide documentation”h]”hŒProvide documentation”…””}”(hjh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´KUhj ubjÎ)”}”(hhh]”hì)”}”(hŒ¨A documentation file under ``Documentation/filesystems/`` describing the filesystem, its on-disk format, mount options, and any notable design decisions is recommended.”h]”(hŒA documentation file under ”…””}”(hj"h²hh³Nh´Nubj)”}”(hŒ``Documentation/filesystems/``”h]”hŒDocumentation/filesystems/”…””}”(hj*h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj"ubhŒo describing the filesystem, its on-disk format, mount options, and any notable design decisions is recommended.”…””}”(hj"h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KRhjubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhj ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´KUhj´h²hubeh}”(h]”h ]”h"]”h$]”h&]”uh1j²hj“h²hh³hÇh´Nubeh}”(h]”Œtechnical-requirements”ah ]”h"]”Œtechnical requirements”ah$]”h&]”uh1hÖhhØh²hh³hÇh´K+ubh×)”}”(hhh]”(hÜ)”}”(hŒ)Community and Maintainership Expectations”h]”hŒ)Community and Maintainership Expectations”…””}”(hj_h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÛhj\h²hh³hÇh´KXubhì)”}”(hŒšMerging a filesystem is a long-term commitment. The kernel community needs confidence that the filesystem will be actively maintained after it is merged.”h]”hŒšMerging a filesystem is a long-term commitment. The kernel community needs confidence that the filesystem will be actively maintained after it is merged.”…””}”(hjmh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KZhj\h²hubj³)”}”(hhh]”(j¸)”}”(hXrIdentified maintainers The submission must include a ``MAINTAINERS`` entry with at least one maintainer (``M:``), a mailing list (``L:``), and a git tree (``T:``). Having two or more maintainers is strongly preferred so that coverage does not depend on a single person. The maintainers are expected to be the primary points of contact for the filesystem going forward. ”h]”(j¾)”}”(hŒIdentified maintainers”h]”hŒIdentified maintainers”…””}”(hj‚h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´Kchj~ubjÎ)”}”(hhh]”hì)”}”(hXZThe submission must include a ``MAINTAINERS`` entry with at least one maintainer (``M:``), a mailing list (``L:``), and a git tree (``T:``). Having two or more maintainers is strongly preferred so that coverage does not depend on a single person. The maintainers are expected to be the primary points of contact for the filesystem going forward.”h]”(hŒThe submission must include a ”…””}”(hj“h²hh³Nh´Nubj)”}”(hŒ``MAINTAINERS``”h]”hŒ MAINTAINERS”…””}”(hj›h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj“ubhŒ% entry with at least one maintainer (”…””}”(hj“h²hh³Nh´Nubj)”}”(hŒ``M:``”h]”hŒM:”…””}”(hj­h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj“ubhŒ), a mailing list (”…””}”(hj“h²hh³Nh´Nubj)”}”(hŒ``L:``”h]”hŒL:”…””}”(hj¿h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj“ubhŒ), and a git tree (”…””}”(hj“h²hh³Nh´Nubj)”}”(hŒ``T:``”h]”hŒT:”…””}”(hjÑh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj“ubhŒÐ). Having two or more maintainers is strongly preferred so that coverage does not depend on a single person. The maintainers are expected to be the primary points of contact for the filesystem going forward.”…””}”(hj“h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K_hjubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhj~ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´Kchj{ubj¸)”}”(hXDemonstrated commitment A track record of maintaining kernel code -- for example, in other subsystems -- significantly strengthens the case for a new filesystem. Maintainers who are already known and trusted within the community face less friction during review. ”h]”(j¾)”}”(hŒDemonstrated commitment”h]”hŒDemonstrated commitment”…””}”(hjùh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´KihjõubjÎ)”}”(hhh]”hì)”}”(hŒîA track record of maintaining kernel code -- for example, in other subsystems -- significantly strengthens the case for a new filesystem. Maintainers who are already known and trusted within the community face less friction during review.”h]”hŒîA track record of maintaining kernel code -- for example, in other subsystems -- significantly strengthens the case for a new filesystem. Maintainers who are already known and trusted within the community face less friction during review.”…””}”(hj h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´Kfhjubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhjõubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´Kihj{h²hubj¸)”}”(hŒÜSustained backing Major filesystems in Linux have organizational or corporate support behind their development. Filesystems that depend entirely on volunteer effort face higher scrutiny about their long-term viability. ”h]”(j¾)”}”(hŒSustained backing”h]”hŒSustained backing”…””}”(hj(h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´Knhj$ubjÎ)”}”(hhh]”hì)”}”(hŒÉMajor filesystems in Linux have organizational or corporate support behind their development. Filesystems that depend entirely on volunteer effort face higher scrutiny about their long-term viability.”h]”hŒÉMajor filesystems in Linux have organizational or corporate support behind their development. Filesystems that depend entirely on volunteer effort face higher scrutiny about their long-term viability.”…””}”(hj9h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´Klhj6ubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhj$ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´Knhj{h²hubj¸)”}”(hXBResponsiveness The maintainer is expected to respond to bug reports, address review feedback, and adapt the filesystem to VFS infrastructure changes such as folio conversions, iomap migration, and mount API updates. Unresponsive maintainership is one of the primary reasons filesystems end up on the path to deprecation. ”h]”(j¾)”}”(hŒResponsiveness”h]”hŒResponsiveness”…””}”(hjWh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´KuhjSubjÎ)”}”(hhh]”hì)”}”(hX2The maintainer is expected to respond to bug reports, address review feedback, and adapt the filesystem to VFS infrastructure changes such as folio conversions, iomap migration, and mount API updates. Unresponsive maintainership is one of the primary reasons filesystems end up on the path to deprecation.”h]”hX2The maintainer is expected to respond to bug reports, address review feedback, and adapt the filesystem to VFS infrastructure changes such as folio conversions, iomap migration, and mount API updates. Unresponsive maintainership is one of the primary reasons filesystems end up on the path to deprecation.”…””}”(hjhh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´Kqhjeubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhjSubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´Kuhj{h²hubj¸)”}”(hŒÞUser base Clearly describe who the users of this filesystem are and the scale of the user base. Filesystems with a very small or unclear user base face a harder path to acceptance and a higher risk of future deprecation. ”h]”(j¾)”}”(hŒ User base”h]”hŒ User base”…””}”(hj†h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´Kzhj‚ubjÎ)”}”(hhh]”hì)”}”(hŒÓClearly describe who the users of this filesystem are and the scale of the user base. Filesystems with a very small or unclear user base face a harder path to acceptance and a higher risk of future deprecation.”h]”hŒÓClearly describe who the users of this filesystem are and the scale of the user base. Filesystems with a very small or unclear user base face a harder path to acceptance and a higher risk of future deprecation.”…””}”(hj—h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´Kxhj”ubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhj‚ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´Kzhj{h²hubj¸)”}”(hX Building your track record A practical way to demonstrate many of the qualities above is to maintain the filesystem out-of-tree for a period before requesting a merge. This shows sustained commitment, builds a visible user base, and gives reviewers confidence that the code and its maintainer will persist after merging. That said, it is recognized that for some filesystems the user base grows significantly only after upstreaming, so a compelling case for expected adoption can substitute for a large existing user base. ”h]”(j¾)”}”(hŒBuilding your track record”h]”hŒBuilding your track record”…””}”(hjµh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j½h³hÇh´K„hj±ubjÎ)”}”(hhh]”hì)”}”(hXðA practical way to demonstrate many of the qualities above is to maintain the filesystem out-of-tree for a period before requesting a merge. This shows sustained commitment, builds a visible user base, and gives reviewers confidence that the code and its maintainer will persist after merging. That said, it is recognized that for some filesystems the user base grows significantly only after upstreaming, so a compelling case for expected adoption can substitute for a large existing user base.”h]”hXðA practical way to demonstrate many of the qualities above is to maintain the filesystem out-of-tree for a period before requesting a merge. This shows sustained commitment, builds a visible user base, and gives reviewers confidence that the code and its maintainer will persist after merging. That said, it is recognized that for some filesystems the user base grows significantly only after upstreaming, so a compelling case for expected adoption can substitute for a large existing user base.”…””}”(hjÆh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K}hjÃubah}”(h]”h ]”h"]”h$]”h&]”uh1jÍhj±ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j·h³hÇh´K„hj{h²hubeh}”(h]”h ]”h"]”h$]”h&]”uh1j²hj\h²hh³hÇh´Nubeh}”(h]”Œ)community-and-maintainership-expectations”ah ]”h"]”Œ)community and maintainership expectations”ah$]”h&]”uh1hÖhhØh²hh³hÇh´KXubh×)”}”(hhh]”(hÜ)”}”(hŒSubmission Process”h]”hŒSubmission Process”…””}”(hjñh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÛhjîh²hh³hÇh´K‡ubhì)”}”(hŒÿThis section covers what is specific to filesystem submissions, over and above the normal submission advice in :ref:`Documentation/process/submitting-patches.rst ` and :ref:`Documentation/process/submit-checklist.rst `.”h]”(hŒoThis section covers what is specific to filesystem submissions, over and above the normal submission advice in ”…””}”(hjÿh²hh³Nh´Nubh)”}”(hŒG:ref:`Documentation/process/submitting-patches.rst `”h]”jß)”}”(hj h]”hŒ,Documentation/process/submitting-patches.rst”…””}”(hj h²hh³Nh´Nubah}”(h]”h ]”(jêŒstd”Œstd-ref”eh"]”h$]”h&]”uh1jÞhjubah}”(h]”h ]”h"]”h$]”h&]”Œrefdoc”j÷Œ refdomain”jŒreftype”Œref”Œ refexplicit”ˆŒrefwarn”ˆjýŒsubmittingpatches”uh1hh³hÇh´K‰hjÿubhŒ and ”…””}”(hjÿh²hh³Nh´Nubh)”}”(hŒC:ref:`Documentation/process/submit-checklist.rst `”h]”jß)”}”(hj-h]”hŒ*Documentation/process/submit-checklist.rst”…””}”(hj/h²hh³Nh´Nubah}”(h]”h ]”(jêŒstd”Œstd-ref”eh"]”h$]”h&]”uh1jÞhj+ubah}”(h]”h ]”h"]”h$]”h&]”Œrefdoc”j÷Œ refdomain”j9Œreftype”Œref”Œ refexplicit”ˆŒrefwarn”ˆjýŒsubmitchecklist”uh1hh³hÇh´K‰hjÿubhŒ.”…””}”(hjÿh²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K‰hjîh²hubj))”}”(hX)- Send patches to the linux-fsdevel mailing list (``linux-fsdevel@vger.kernel.org``). CC the relevant VFS maintainers as listed in the ``MAINTAINERS`` file under ``FILESYSTEMS (VFS and infrastructure)``. - Structure the submission logically. It is neither acceptable to send one large patch containing the entire filesystem, nor is a replay of the full development history helpful to reviewers. Instead, split the series by topic -- for example: superblock and mount handling, inode operations, directory operations, address space operations, and so on -- so that each patch is reviewable in isolation. - Separate any filesystem-specific ioctls into their own patches with dedicated justification. Interfaces beyond those already common across other filesystems will receive additional scrutiny because they are hard to maintain and may conflict with future generic interfaces. - Expect thorough review. Filesystem code interacts deeply with the VFS, memory management, and block layers, so reviewers will examine the code carefully. Address all review feedback and be prepared for multiple revision cycles. - It may be appropriate to mark the filesystem as experimental in its Kconfig help text for the first few releases to set expectations while the code stabilizes in-tree. ”h]”j/)”}”(hhh]”(j4)”}”(hŒËSend patches to the linux-fsdevel mailing list (``linux-fsdevel@vger.kernel.org``). CC the relevant VFS maintainers as listed in the ``MAINTAINERS`` file under ``FILESYSTEMS (VFS and infrastructure)``. ”h]”hì)”}”(hŒÊSend patches to the linux-fsdevel mailing list (``linux-fsdevel@vger.kernel.org``). CC the relevant VFS maintainers as listed in the ``MAINTAINERS`` file under ``FILESYSTEMS (VFS and infrastructure)``.”h]”(hŒ0Send patches to the linux-fsdevel mailing list (”…””}”(hj`h²hh³Nh´Nubj)”}”(hŒ!``linux-fsdevel@vger.kernel.org``”h]”hŒlinux-fsdevel@vger.kernel.org”…””}”(hjhh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj`ubhŒ5). CC the relevant VFS maintainers as listed in the ”…””}”(hj`h²hh³Nh´Nubj)”}”(hŒ``MAINTAINERS``”h]”hŒ MAINTAINERS”…””}”(hjzh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj`ubhŒ file under ”…””}”(hj`h²hh³Nh´Nubj)”}”(hŒ(``FILESYSTEMS (VFS and infrastructure)``”h]”hŒ$FILESYSTEMS (VFS and infrastructure)”…””}”(hjŒh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj`ubhŒ.”…””}”(hj`h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KŽhj\ubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjYubj4)”}”(hXStructure the submission logically. It is neither acceptable to send one large patch containing the entire filesystem, nor is a replay of the full development history helpful to reviewers. Instead, split the series by topic -- for example: superblock and mount handling, inode operations, directory operations, address space operations, and so on -- so that each patch is reviewable in isolation. ”h]”hì)”}”(hXŽStructure the submission logically. It is neither acceptable to send one large patch containing the entire filesystem, nor is a replay of the full development history helpful to reviewers. Instead, split the series by topic -- for example: superblock and mount handling, inode operations, directory operations, address space operations, and so on -- so that each patch is reviewable in isolation.”h]”hXŽStructure the submission logically. It is neither acceptable to send one large patch containing the entire filesystem, nor is a replay of the full development history helpful to reviewers. Instead, split the series by topic -- for example: superblock and mount handling, inode operations, directory operations, address space operations, and so on -- so that each patch is reviewable in isolation.”…””}”(hj®h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K“hjªubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjYubj4)”}”(hXSeparate any filesystem-specific ioctls into their own patches with dedicated justification. Interfaces beyond those already common across other filesystems will receive additional scrutiny because they are hard to maintain and may conflict with future generic interfaces. ”h]”hì)”}”(hXSeparate any filesystem-specific ioctls into their own patches with dedicated justification. Interfaces beyond those already common across other filesystems will receive additional scrutiny because they are hard to maintain and may conflict with future generic interfaces.”h]”hXSeparate any filesystem-specific ioctls into their own patches with dedicated justification. Interfaces beyond those already common across other filesystems will receive additional scrutiny because they are hard to maintain and may conflict with future generic interfaces.”…””}”(hjÆh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KšhjÂubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjYubj4)”}”(hŒæExpect thorough review. Filesystem code interacts deeply with the VFS, memory management, and block layers, so reviewers will examine the code carefully. Address all review feedback and be prepared for multiple revision cycles. ”h]”hì)”}”(hŒåExpect thorough review. Filesystem code interacts deeply with the VFS, memory management, and block layers, so reviewers will examine the code carefully. Address all review feedback and be prepared for multiple revision cycles.”h]”hŒåExpect thorough review. Filesystem code interacts deeply with the VFS, memory management, and block layers, so reviewers will examine the code carefully. Address all review feedback and be prepared for multiple revision cycles.”…””}”(hjÞh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KŸhjÚubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjYubj4)”}”(hŒ©It may be appropriate to mark the filesystem as experimental in its Kconfig help text for the first few releases to set expectations while the code stabilizes in-tree. ”h]”hì)”}”(hŒ§It may be appropriate to mark the filesystem as experimental in its Kconfig help text for the first few releases to set expectations while the code stabilizes in-tree.”h]”hŒ§It may be appropriate to mark the filesystem as experimental in its Kconfig help text for the first few releases to set expectations while the code stabilizes in-tree.”…””}”(hjöh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K¤hjòubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjYubeh}”(h]”h ]”h"]”h$]”h&]”jƒj„uh1j.h³hÇh´KŽhjUubah}”(h]”h ]”h"]”h$]”h&]”uh1j(h³hÇh´KŽhjîh²hubeh}”(h]”Œsubmission-process”ah ]”h"]”Œsubmission process”ah$]”h&]”uh1hÖhhØh²hh³hÇh´K‡ubh×)”}”(hhh]”(hÜ)”}”(hŒOngoing Obligations”h]”hŒOngoing Obligations”…””}”(hj!h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÛhjh²hh³hÇh´Kªubhì)”}”(hŒaMerging is not the finish line. Maintaining a filesystem in the kernel is an ongoing commitment.”h]”hŒaMerging is not the finish line. Maintaining a filesystem in the kernel is an ongoing commitment.”…””}”(hj/h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K¬hjh²hubj))”}”(hX3- Adapt to VFS infrastructure changes. The VFS layer evolves continuously; maintainers are expected to keep up with conversions such as folio migration, iomap adoption, and mount API updates. - Maintain test coverage. As test suites evolve, the filesystem's test results should be kept current. - Handle security issues and regression promptly. Both those reported by ordinary users and those reported by test bots and fuzzing tools. The filesystem must handle corrupted input gracefully without corrupting memory, hanging, or crashing the kernel. - Engage with the wider filesystem community. Participate on linux-fsdevel, share approaches to common problems, and look for opportunities to reuse shared infrastructure. It is inappropriate to develop in isolation on a private list and surface patches only at merge time. - Filesystems that become unmaintained -- where the maintainer stops responding, infrastructure changes go unadapted, and testing becomes impossible -- are candidates for deprecation and eventual removal from the kernel.”h]”j/)”}”(hhh]”(j4)”}”(hŒ¿Adapt to VFS infrastructure changes. The VFS layer evolves continuously; maintainers are expected to keep up with conversions such as folio migration, iomap adoption, and mount API updates. ”h]”hì)”}”(hŒ¾Adapt to VFS infrastructure changes. The VFS layer evolves continuously; maintainers are expected to keep up with conversions such as folio migration, iomap adoption, and mount API updates.”h]”hŒ¾Adapt to VFS infrastructure changes. The VFS layer evolves continuously; maintainers are expected to keep up with conversions such as folio migration, iomap adoption, and mount API updates.”…””}”(hjHh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K¯hjDubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjAubj4)”}”(hŒfMaintain test coverage. As test suites evolve, the filesystem's test results should be kept current. ”h]”hì)”}”(hŒeMaintain test coverage. As test suites evolve, the filesystem's test results should be kept current.”h]”hŒgMaintain test coverage. As test suites evolve, the filesystem’s test results should be kept current.”…””}”(hj`h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K³hj\ubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjAubj4)”}”(hŒüHandle security issues and regression promptly. Both those reported by ordinary users and those reported by test bots and fuzzing tools. The filesystem must handle corrupted input gracefully without corrupting memory, hanging, or crashing the kernel. ”h]”hì)”}”(hŒûHandle security issues and regression promptly. Both those reported by ordinary users and those reported by test bots and fuzzing tools. The filesystem must handle corrupted input gracefully without corrupting memory, hanging, or crashing the kernel.”h]”hŒûHandle security issues and regression promptly. Both those reported by ordinary users and those reported by test bots and fuzzing tools. The filesystem must handle corrupted input gracefully without corrupting memory, hanging, or crashing the kernel.”…””}”(hjxh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K¶hjtubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjAubj4)”}”(hXEngage with the wider filesystem community. Participate on linux-fsdevel, share approaches to common problems, and look for opportunities to reuse shared infrastructure. It is inappropriate to develop in isolation on a private list and surface patches only at merge time. ”h]”hì)”}”(hXEngage with the wider filesystem community. Participate on linux-fsdevel, share approaches to common problems, and look for opportunities to reuse shared infrastructure. It is inappropriate to develop in isolation on a private list and surface patches only at merge time.”h]”hXEngage with the wider filesystem community. Participate on linux-fsdevel, share approaches to common problems, and look for opportunities to reuse shared infrastructure. It is inappropriate to develop in isolation on a private list and surface patches only at merge time.”…””}”(hjh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´K»hjŒubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjAubj4)”}”(hŒÚFilesystems that become unmaintained -- where the maintainer stops responding, infrastructure changes go unadapted, and testing becomes impossible -- are candidates for deprecation and eventual removal from the kernel.”h]”hì)”}”(hŒÚFilesystems that become unmaintained -- where the maintainer stops responding, infrastructure changes go unadapted, and testing becomes impossible -- are candidates for deprecation and eventual removal from the kernel.”h]”hŒÚFilesystems that become unmaintained -- where the maintainer stops responding, infrastructure changes go unadapted, and testing becomes impossible -- are candidates for deprecation and eventual removal from the kernel.”…””}”(hj¨h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hëh³hÇh´KÀhj¤ubah}”(h]”h ]”h"]”h$]”h&]”uh1j3hjAubeh}”(h]”h ]”h"]”h$]”h&]”jƒj„uh1j.h³hÇh´K¯hj=ubah}”(h]”h ]”h"]”h$]”h&]”uh1j(h³hÇh´K¯hjh²hubeh}”(h]”Œongoing-obligations”ah ]”h"]”Œongoing obligations”ah$]”h&]”uh1hÖhhØh²hh³hÇh´Kªubeh}”(h]”(hÕŒid1”eh ]”h"]”(Œadding new filesystems”Œadding_new_filesystems”eh$]”h&]”uh1hÖhhh²hh³hÇh´KŒexpect_referenced_by_name”}”jÖhÊsŒexpect_referenced_by_id”}”hÕhÊsubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”hÇuh1hŒcurrent_source”NŒ current_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(hÛNŒ generator”NŒ datestamp”NŒ source_link”NŒ source_url”NŒ toc_backlinks”Œentry”Œfootnote_backlinks”KŒ sectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒ strip_classes”NŒ report_level”KŒ halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ traceback”ˆŒinput_encoding”Œ utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”jŒerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œ language_code”Œen”Œrecord_dependencies”NŒconfig”NŒ id_prefix”hŒauto_id_prefix”Œid”Œ dump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”hÇŒ _destination”NŒ _config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒ raw_enabled”KŒline_length_limit”M'Œpep_references”NŒ pep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒ rfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œ smart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œ docinfo_xform”KŒsectsubtitle_xform”‰Œ image_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”hÕ]”hÊasŒnameids”}”(jÖhÕjÕjÒjjjYjVjòjïjëjèjjjÍjÊuŒ nametypes”}”(jÖˆjÕ‰j‰jY‰jòˆjë‰j‰j͉uh}”(hÕhØjÒhØjj jVj“jïjéjèj\jjîjÊjuŒ footnote_refs”}”Œ citation_refs”}”Œ autofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ footnotes”]”Œ citations”]”Œautofootnote_start”KŒsymbol_footnote_start”KŒ id_counter”Œ collections”ŒCounter”“”}”jKs…”R”Œparse_messages”]”Œtransform_messages”]”hŒsystem_message”“”)”}”(hhh]”hì)”}”(hhh]”hŒ