kernel/linux.git/Documentation/filesystems, branch v7.1.8

erofs: remove fscache backend entirely

2026-08-09T18:26:29+00:00

[ Upstream commit c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56 ] EROFS over fscache was introduced to provide image lazy pulling functionality. After the feature landed, the fscache subsystem made netfs a new hard dependency, which is unexpected for a local filesystem and has an kernel-defined caching hierarchy which could be inflexible compared to the fanotify pre-content hooks. Therefore, this feature has been deprecated for almost two years. As EROFS file-backed mounts and fanotify pre-content hooks both upstream for a while and already providing equivalent functionality (erofs-utils has supported fanotify pre-content hooks), let's remove the fscache backend now. The main application of this feature is Nydus [1], and they plan to move to use fanotify pre-content hooks in the near future too. I hope this patch can be merged into Linux 7.2, which is also motivated by newly found implementation issues [2][3] that are not worth investigating given the deprecation and limited development resources. The associated fscache/cachefiles cleanup patch will follow separately through the vfs tree (netfs) later: it seems fine since the codebase is isolated by CONFIG_CACHEFILES_ONDEMAND. [1] https://github.com/dragonflyoss/nydus/blob/v2.1.0/docs/nydus-fscache.md [2] https://github.com/dragonflyoss/nydus/pull/1824 [3] https://lore.kernel.org/r/20260619135800.1594811-1-michael.bommarito@gmail.com Acked-by: Jingbo Xu Signed-off-by: Gao Xiang Stable-dep-of: 96b2dbbe58a1 ("erofs: ensure valid f_path for page cache sharing") Signed-off-by: Sasha Levin

Documentation: proc: fix section numbering in table of contents

2026-07-24T14:19:03+00:00

[ Upstream commit 97a7bd8c2c58a6d820df563d1d0f68aafec45477 ] Commit e24ccaaf7ec4 ("block: remove last remaining traces of IDE documentation") removed the IDE section but left its table of contents entry behind. Fix the stale entry and renumber the following sections. Fixes: e24ccaaf7ec4 ("block: remove last remaining traces of IDE documentation") Signed-off-by: Baolin Liu Acked-by: Randy Dunlap Signed-off-by: Jonathan Corbet Message-ID: <20260424090654.19229-1-liubaolin12138@163.com> Signed-off-by: Sasha Levin

Merge tag 'fs_for_v7.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

2026-04-27T23:45:39+00:00

Pull isofs and udf fixes from Jan Kara: "Several isofs and udf fixes" * tag 'fs_for_v7.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: docs: isofs: replace dead ECMA-119 FTP link udf: reject descriptors with oversized CRC length isofs: use QSTR_LEN() in isofs_cmp isofs: validate block number from NFS file handle in isofs_export_iget isofs: validate Rock Ridge CE continuation extent against volume size

docs: isofs: replace dead ECMA-119 FTP link

2026-04-27T10:58:07+00:00

The original link is no longer valid. Replace it with the official PDF of the 2nd edition. The new link points to the exact 2nd edition that the existing comment in isofs.rst refers to. Signed-off-by: Ziran Zhang Link: https://patch.msgid.link/20260425142943.6809-1-zhangcoder@yeah.net Signed-off-by: Jan Kara

Merge tag 'pull-dcache-busy-wait' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2026-04-21T14:30:44+00:00

Pull dcache busy loop updates from Al Viro: "Fix livelocks in shrink_dcache_tree() If shrink_dcache_tree() finds a dentry in the middle of being killed by another thread, it has to wait until the victim finishes dying, gets detached from the tree and ceases to pin its parent. The way we used to deal with that amounted to busy-wait; unfortunately, it's not just inefficient but can lead to reliably reproducible hard livelocks. Solved by having shrink_dentry_tree() attach a completion to such dentry, with dentry_unlist() calling complete() on all objects attached to it. With a bit of care it can be done without growing struct dentry or adding overhead in normal case" * tag 'pull-dcache-busy-wait' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: get rid of busy-waiting in shrink_dcache_tree() dcache.c: more idiomatic "positives are not allowed" sanity checks struct dentry: make ->d_u anonymous for_each_alias(): helper macro for iterating through dentries of given inode

Merge tag 'nfsd-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

2026-04-20T17:44:02+00:00

Pull nfsd updates from Chuck Lever: - filehandle signing to defend against filehandle-guessing attacks (Benjamin Coddington) The server now appends a SipHash-2-4 MAC to each filehandle when the new "sign_fh" export option is enabled. NFSD then verifies filehandles received from clients against the expected MAC; mismatches return NFS error STALE - convert the entire NLMv4 server-side XDR layer from hand-written C to xdrgen-generated code, spanning roughly thirty patches (Chuck Lever) XDR functions are generally boilerplate code and are easy to get wrong. The goals of this conversion are improved memory safety, lower maintenance burden, and groundwork for eventual Rust code generation for these functions. - improve pNFS block/SCSI layout robustness with two related changes (Dai Ngo) SCSI persistent reservation fencing is now tracked per client and per device via an xarray, to avoid both redundant preempt operations on devices already fenced and a potential NFSD deadlock when all nfsd threads are waiting for a layout return. - scalability and infrastructure improvements Sincere thanks to all contributors, reviewers, testers, and bug reporters who participated in the v7.1 NFSD development cycle. * tag 'nfsd-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (83 commits) NFSD: Docs: clean up pnfs server timeout docs nfsd: fix comment typo in nfsxdr nfsd: fix comment typo in nfs3xdr NFSD: convert callback RPC program to per-net namespace NFSD: use per-operation statidx for callback procedures svcrdma: Use contiguous pages for RDMA Read sink buffers SUNRPC: Add svc_rqst_page_release() helper SUNRPC: xdr.h: fix all kernel-doc warnings svcrdma: Factor out WR chain linking into helper svcrdma: Add Write chunk WRs to the RPC's Send WR chain svcrdma: Clean up use of rdma->sc_pd->device svcrdma: Clean up use of rdma->sc_pd->device in Receive paths svcrdma: Add fair queuing for Send Queue access SUNRPC: Optimize rq_respages allocation in svc_alloc_arg SUNRPC: Track consumed rq_pages entries svcrdma: preserve rq_next_page in svc_rdma_save_io_pages SUNRPC: Handle NULL entries in svc_rqst_release_pages SUNRPC: Allocate a separate Reply page array SUNRPC: Tighten bounds checking in svc_rqst_replace_page NFSD: Sign filehandles ...

Merge tag 'mm-stable-2026-04-18-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-19T15:01:17+00:00

Pull more MM updates from Andrew Morton: - "Eliminate Dying Memory Cgroup" (Qi Zheng and Muchun Song) Address the longstanding "dying memcg problem". A situation wherein a no-longer-used memory control group will hang around for an extended period pointlessly consuming memory - "fix unexpected type conversions and potential overflows" (Qi Zheng) Fix a couple of potential 32-bit/64-bit issues which were identified during review of the "Eliminate Dying Memory Cgroup" series - "kho: history: track previous kernel version and kexec boot count" (Breno Leitao) Use Kexec Handover (KHO) to pass the previous kernel's version string and the number of kexec reboots since the last cold boot to the next kernel, and print it at boot time - "liveupdate: prevent double preservation" (Pasha Tatashin) Teach LUO to avoid managing the same file across different active sessions - "liveupdate: Fix module unloading and unregister API" (Pasha Tatashin) Address an issue with how LUO handles module reference counting and unregistration during module unloading - "zswap pool per-CPU acomp_ctx simplifications" (Kanchana Sridhar) Simplify and clean up the zswap crypto compression handling and improve the lifecycle management of zswap pool's per-CPU acomp_ctx resources - "mm/damon/core: fix damon_call()/damos_walk() vs kdmond exit race" (SeongJae Park) Address unlikely but possible leaks and deadlocks in damon_call() and damon_walk() - "mm/damon/core: validate damos_quota_goal->nid" (SeongJae Park) Fix a couple of root-only wild pointer dereferences - "Docs/admin-guide/mm/damon: warn commit_inputs vs other params race" (SeongJae Park) Update the DAMON documentation to warn operators about potential races which can occur if the commit_inputs parameter is altered at the wrong time - "Minor hmm_test fixes and cleanups" (Alistair Popple) Bugfixes and a cleanup for the HMM kernel selftests - "Modify memfd_luo code" (Chenghao Duan) Cleanups, simplifications and speedups to the memfd_lou code - "mm, kvm: allow uffd support in guest_memfd" (Mike Rapoport) Support for userfaultfd in guest_memfd - "selftests/mm: skip several tests when thp is not available" (Chunyu Hu) Fix several issues in the selftests code which were causing breakage when the tests were run on CONFIG_THP=n kernels - "mm/mprotect: micro-optimization work" (Pedro Falcato) A couple of nice speedups for mprotect() - "MAINTAINERS: update KHO and LIVE UPDATE entries" (Pratyush Yadav) Document upcoming changes in the maintenance of KHO, LUO, memfd_luo, kexec, crash, kdump and probably other kexec-based things - they are being moved out of mm.git and into a new git tree * tag 'mm-stable-2026-04-18-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (121 commits) MAINTAINERS: add page cache reviewer mm/vmscan: avoid false-positive -Wuninitialized warning MAINTAINERS: update Dave's kdump reviewer email address MAINTAINERS: drop include/linux/liveupdate from LIVE UPDATE MAINTAINERS: drop include/linux/kho/abi/ from KHO MAINTAINERS: update KHO and LIVE UPDATE maintainers MAINTAINERS: update kexec/kdump maintainers entries mm/migrate_device: remove dead migration entry check in migrate_vma_collect_huge_pmd() selftests: mm: skip charge_reserved_hugetlb without killall userfaultfd: allow registration of ranges below mmap_min_addr mm/vmstat: fix vmstat_shepherd double-scheduling vmstat_update mm/hugetlb: fix early boot crash on parameters without '=' separator zram: reject unrecognized type= values in recompress_store() docs: proc: document ProtectionKey in smaps mm/mprotect: special-case small folios when applying permissions mm/mprotect: move softleaf code out of the main function mm: remove '!root_reclaim' checking in should_abort_scan() mm/sparse: fix comment for section map alignment mm/page_io: use sio->len for PSWPIN accounting in sio_read_complete() selftests/mm: transhuge_stress: skip the test when thp not available ...

docs: proc: document ProtectionKey in smaps

2026-04-18T07:10:55+00:00

The ProtectionKey entry was added in v4.9; back then it was x86-specific, but it now lives in generic code and applies to all architectures supporting pkeys (currently x86, power, arm64). Time to document it: add a paragraph to proc.rst about the ProtectionKey entry. [akpm@linux-foundation.org: s/system/hardware/, per review discussion] [akpm@linux-foundation.org: s/hardware/CPU/] Link: https://lore.kernel.org/20260407125133.564182-1-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky Reported-by: Yury Khrustalev Acked-by: Vlastimil Babka (SUSE) Reviewed-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes Acked-by: Dave Hansen Cc: Jonathan Corbet Cc: Kevin Brodsky Cc: Marc Rutland Cc: Shuah Khan Cc: Randy Dunlap Signed-off-by: Andrew Morton

Merge tag 'ntfs-for-7.1-rc1-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/ntfs

2026-04-17T23:35:49+00:00

Pull ntfs resurrection from Namjae Jeon: "Ever since Kari Argillander’s 2022 report [1] regarding the state of the ntfs3 driver, I have spent the last 4 years working to provide full write support and current trends (iomap, no buffer head, folio), enhanced performance, stable maintenance, utility support including fsck for NTFS in Linux. This new implementation is built upon the clean foundation of the original read-only NTFS driver, adding: - Write support: Implemented full write support based on the classic read-only NTFS driver. Added delayed allocation to improve write performance through multi-cluster allocation and reduced fragmentation of the cluster bitmap. - iomap conversion: Switched buffered IO (reads/writes), direct IO, file extent mapping, readpages, and writepages to use iomap. - Remove buffer_head: Completely removed buffer_head usage by converting to folios. As a result, the dependency on CONFIG_BUFFER_HEAD has been removed from Kconfig. - Stability improvements: The new ntfs driver passes 326 xfstests, compared to 273 for ntfs3. All tests passed by ntfs3 are a complete subset of the tests passed by this implementation. Added support for fallocate, idmapped mounts, permissions, and more. xfstests Results report: Total tests run: 787 Passed : 326 Failed : 38 Skipped : 423 Failed tests breakdown: - 34 tests require metadata journaling - 4 other tests: 094: No unwritten extent concept in NTFS on-disk format 563: cgroup v2 aware writeback accounting not supported 631: RENAME_WHITEOUT support required 787: NFS delegation test" Link: https://lore.kernel.org/all/da20d32b-5185-f40b-48b8-2986922d8b25@stargateuniverse.net/ [1] [ Let's see if this undead filesystem ends up being of the "Easter miracle" kind, or the "Nosferatu of filesystems" kind... ] * tag 'ntfs-for-7.1-rc1-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/ntfs: (46 commits) ntfs: remove redundant out-of-bound checks ntfs: add bound checking to ntfs_external_attr_find ntfs: add bound checking to ntfs_attr_find ntfs: fix ignoring unreachable code warnings ntfs: fix inconsistent indenting warnings ntfs: fix variable dereferenced before check warnings ntfs: prefer IS_ERR_OR_NULL() over manual NULL check ntfs: harden ntfs_listxattr against EA entries ntfs: harden ntfs_ea_lookup against malformed EA entries ntfs: check $EA query-length in ntfs_ea_get ntfs: validate WSL EA payload sizes ntfs: fix WSL ea restore condition ntfs: add missing newlines to pr_err() messages ntfs: fix pointer/integer casting warnings ntfs: use ->mft_no instead of ->i_ino in prints ntfs: change mft_no type to u64 ntfs: select FS_IOMAP in Kconfig ntfs: add MODULE_ALIAS_FS ntfs: reduce stack usage in ntfs_write_mft_block() ntfs: fix sysctl table registration and path ...

Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-15T19:59:16+00:00

Pull MM updates from Andrew Morton: - "maple_tree: Replace big node with maple copy" (Liam Howlett) Mainly prepararatory work for ongoing development but it does reduce stack usage and is an improvement. - "mm, swap: swap table phase III: remove swap_map" (Kairui Song) Offers memory savings by removing the static swap_map. It also yields some CPU savings and implements several cleanups. - "mm: memfd_luo: preserve file seals" (Pratyush Yadav) File seal preservation to LUO's memfd code - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan Chen) Additional userspace stats reportng to zswap - "arch, mm: consolidate empty_zero_page" (Mike Rapoport) Some cleanups for our handling of ZERO_PAGE() and zero_pfn - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu Han) A robustness improvement and some cleanups in the kmemleak code - "Improve khugepaged scan logic" (Vernon Yang) Improve khugepaged scan logic and reduce CPU consumption by prioritizing scanning tasks that access memory frequently - "Make KHO Stateless" (Jason Miu) Simplify Kexec Handover by transitioning KHO from an xarray-based metadata tracking system with serialization to a radix tree data structure that can be passed directly to the next kernel - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas Ballasi and Steven Rostedt) Enhance vmscan's tracepointing - "mm: arch/shstk: Common shadow stack mapping helper and VM_NOHUGEPAGE" (Catalin Marinas) Cleanup for the shadow stack code: remove per-arch code in favour of a generic implementation - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin) Fix a WARN() which can be emitted the KHO restores a vmalloc area - "mm: Remove stray references to pagevec" (Tal Zussman) Several cleanups, mainly udpating references to "struct pagevec", which became folio_batch three years ago - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl Shutsemau) Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail pages encode their relationship to the head page - "mm/damon/core: improve DAMOS quota efficiency for core layer filters" (SeongJae Park) Improve two problematic behaviors of DAMOS that makes it less efficient when core layer filters are used - "mm/damon: strictly respect min_nr_regions" (SeongJae Park) Improve DAMON usability by extending the treatment of the min_nr_regions user-settable parameter - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka) The proper fix for a previously hotfixed SMP=n issue. Code simplifications and cleanups ensued - "mm: cleanups around unmapping / zapping" (David Hildenbrand) A bunch of cleanups around unmapping and zapping. Mostly simplifications, code movements, documentation and renaming of zapping functions - "support batched checking of the young flag for MGLRU" (Baolin Wang) Batched checking of the young flag for MGLRU. It's part cleanups; one benchmark shows large performance benefits for arm64 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner) memcg cleanup and robustness improvements - "Allow order zero pages in page reporting" (Yuvraj Sakshith) Enhance free page reporting - it is presently and undesirably order-0 pages when reporting free memory. - "mm: vma flag tweaks" (Lorenzo Stoakes) Cleanup work following from the recent conversion of the VMA flags to a bitmap - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae Park) Add some more developer-facing debug checks into DAMON core - "mm/damon: test and document power-of-2 min_region_sz requirement" (SeongJae Park) An additional DAMON kunit test and makes some adjustments to the addr_unit parameter handling - "mm/damon/core: make passed_sample_intervals comparisons overflow-safe" (SeongJae Park) Fix a hard-to-hit time overflow issue in DAMON core - "mm/damon: improve/fixup/update ratio calculation, test and documentation" (SeongJae Park) A batch of misc/minor improvements and fixups for DAMON - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David Hildenbrand) Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code movement was required. - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky) A somewhat random mix of fixups, recompression cleanups and improvements in the zram code - "mm/damon: support multiple goal-based quota tuning algorithms" (SeongJae Park) Extend DAMOS quotas goal auto-tuning to support multiple tuning algorithms that users can select - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao) Fix the khugpaged sysfs handling so we no longer spam the logs with reams of junk when starting/stopping khugepaged - "mm: improve map count checks" (Lorenzo Stoakes) Provide some cleanups and slight fixes in the mremap, mmap and vma code - "mm/damon: support addr_unit on default monitoring targets for modules" (SeongJae Park) Extend the use of DAMON core's addr_unit tunable - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache) Cleanups to khugepaged and is a base for Nico's planned khugepaged mTHP support - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand) Code movement and cleanups in the memhotplug and sparsemem code - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup CONFIG_MIGRATION" (David Hildenbrand) Rationalize some memhotplug Kconfig support - "change young flag check functions to return bool" (Baolin Wang) Cleanups to change all young flag check functions to return bool - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh Law and SeongJae Park) Fix a few potential DAMON bugs - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo Stoakes) Convert a lot of the existing use of the legacy vm_flags_t data type to the new vma_flags_t type which replaces it. Mainly in the vma code. - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes) Expand the mmap_prepare functionality, which is intended to replace the deprecated f_op->mmap hook which has been the source of bugs and security issues for some time. Cleanups, documentation, extension of mmap_prepare into filesystem drivers - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes) Simplify and clean up zap_huge_pmd(). Additional cleanups around vm_normal_folio_pmd() and the softleaf functionality are performed. * tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm: fix deferred split queue races during migration mm/khugepaged: fix issue with tracking lock mm/huge_memory: add and use has_deposited_pgtable() mm/huge_memory: add and use normal_or_softleaf_folio_pmd() mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio() mm/huge_memory: separate out the folio part of zap_huge_pmd() mm/huge_memory: use mm instead of tlb->mm mm/huge_memory: remove unnecessary sanity checks mm/huge_memory: deduplicate zap deposited table call mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE() mm/huge_memory: add a common exit path to zap_huge_pmd() mm/huge_memory: handle buggy PMD entry in zap_huge_pmd() mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc mm/huge: avoid big else branch in zap_huge_pmd() mm/huge_memory: simplify vma_is_specal_huge() mm: on remap assert that input range within the proposed VMA mm: add mmap_action_map_kernel_pages[_full]() uio: replace deprecated mmap hook with mmap_prepare in uio_info drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare mm: allow handling of stacked mmap_prepare hooks in more drivers ...