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2025-05-31Merge tag 'mm-stable-2025-05-31-14-50' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of creating a pte which addresses the first page in a folio and reduces the amount of plumbing which architecture must implement to provide this. - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of largely unrelated folio infrastructure changes which clean things up and better prepare us for future work. - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory Price adds early-init code to prevent x86 from leaving physical memory unused when physical address regions are not aligned to memory block size. - "mm/compaction: allow more aggressive proactive compaction" from Michal Clapinski provides some tuning of the (sadly, hard-coded (more sadly, not auto-tuned)) thresholds for our invokation of proactive compaction. In a simple test case, the reduction of a guest VM's memory consumption was dramatic. - "Minor cleanups and improvements to swap freeing code" from Kemeng Shi provides some code cleaups and a small efficiency improvement to this part of our swap handling code. - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin adds the ability for a ptracer to modify syscalls arguments. At this time we can alter only "system call information that are used by strace system call tampering, namely, syscall number, syscall arguments, and syscall return value. This series should have been incorporated into mm.git's "non-MM" branch, but I goofed. - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl against /proc/pid/pagemap. This permits CRIU to more efficiently get at the info about guard regions. - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan implements that fix. No runtime effect is expected because validate_page_before_insert() happens to fix up this error. - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David Hildenbrand basically brings uprobe text poking into the current decade. Remove a bunch of hand-rolled implementation in favor of using more current facilities. - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman Khandual provides enhancements and generalizations to the pte dumping code. This might be needed when 128-bit Page Table Descriptors are enabled for ARM. - "Always call constructor for kernel page tables" from Kevin Brodsky ensures that the ctor/dtor is always called for kernel pgtables, as it already is for user pgtables. This permits the addition of more functionality such as "insert hooks to protect page tables". This change does result in various architectures performing unnecesary work, but this is fixed up where it is anticipated to occur. - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice Ryhl adds plumbing to permit Rust access to core MM structures. - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo Stoakes takes advantage of some VMA merging opportunities which we've been missing for 15 years. - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from SeongJae Park optimizes process_madvise()'s TLB flushing. Instead of flushing each address range in the provided iovec, we batch the flushing across all the iovec entries. The syscall's cost was approximately halved with a microbenchmark which was designed to load this particular operation. - "Track node vacancy to reduce worst case allocation counts" from Sidhartha Kumar makes the maple tree smarter about its node preallocation. stress-ng mmap performance increased by single-digit percentages and the amount of unnecessarily preallocated memory was dramaticelly reduced. - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes a few unnecessary things which Baoquan noted when reading the code. - ""Enhance sysfs handling for memory hotplug in weighted interleave" from Rakie Kim "enhances the weighted interleave policy in the memory management subsystem by improving sysfs handling, fixing memory leaks, and introducing dynamic sysfs updates for memory hotplug support". Fixes things on error paths which we are unlikely to hit. - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory" from SeongJae Park introduces new DAMOS quota goal metrics which eliminate the manual tuning which is required when utilizing DAMON for memory tiering. - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He provides cleanups and small efficiency improvements which Baoquan found via code inspection. - "vmscan: enforce mems_effective during demotion" from Gregory Price changes reclaim to respect cpuset.mems_effective during demotion when possible. because presently, reclaim explicitly ignores cpuset.mems_effective when demoting, which may cause the cpuset settings to violated. This is useful for isolating workloads on a multi-tenant system from certain classes of memory more consistently. - "Clean up split_huge_pmd_locked() and remove unnecessary folio pointers" from Gavin Guo provides minor cleanups and efficiency gains in in the huge page splitting and migrating code. - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache for `struct mem_cgroup', yielding improved memory utilization. - "add max arg to swappiness in memory.reclaim and lru_gen" from Zhongkun He adds a new "max" argument to the "swappiness=" argument for memory.reclaim MGLRU's lru_gen. This directs proactive reclaim to reclaim from only anon folios rather than file-backed folios. - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the first step on the path to permitting the kernel to maintain existing VMs while replacing the host kernel via file-based kexec. At this time only memblock's reserve_mem is preserved. - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides and uses a smarter way of looping over a pfn range. By skipping ranges of invalid pfns. - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning when a task is pinned a single NUMA mode. Dramatic performance benefits were seen in some real world cases. - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank Garg addresses a warning which occurs during memory compaction when using JFS. - "move all VMA allocation, freeing and duplication logic to mm" from Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more appropriate mm/vma.c. - "mm, swap: clean up swap cache mapping helper" from Kairui Song provides code consolidation and cleanups related to the folio_index() function. - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that. - "memcg: Fix test_memcg_min/low test failures" from Waiman Long addresses some bogus failures which are being reported by the test_memcontrol selftest. - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo Stoakes commences the deprecation of file_operations.mmap() in favor of the new file_operations.mmap_prepare(). The latter is more restrictive and prevents drivers from messing with things in ways which, amongst other problems, may defeat VMA merging. - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples the per-cpu memcg charge cache from the objcg's one. This is a step along the way to making memcg and objcg charging NMI-safe, which is a BPF requirement. - "mm/damon: minor fixups and improvements for code, tests, and documents" from SeongJae Park is yet another batch of miscellaneous DAMON changes. Fix and improve minor problems in code, tests and documents. - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg stats to be irq safe. Another step along the way to making memcg charging and stats updates NMI-safe, a BPF requirement. - "Let unmap_hugepage_range() and several related functions take folio instead of page" from Fan Ni provides folio conversions in the hugetlb code. * tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits) mm: pcp: increase pcp->free_count threshold to trigger free_high mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range() mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page mm/hugetlb: pass folio instead of page to unmap_ref_private() memcg: objcg stock trylock without irq disabling memcg: no stock lock for cpu hot-unplug memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs memcg: make count_memcg_events re-entrant safe against irqs memcg: make mod_memcg_state re-entrant safe against irqs memcg: move preempt disable to callers of memcg_rstat_updated memcg: memcg_rstat_updated re-entrant safe against irqs mm: khugepaged: decouple SHMEM and file folios' collapse selftests/eventfd: correct test name and improve messages alloc_tag: check mem_profiling_support in alloc_tag_init Docs/damon: update titles and brief introductions to explain DAMOS selftests/damon/_damon_sysfs: read tried regions directories in order mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject() mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat() mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs ...
2025-05-30Merge tag 'pull-automount' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull automount updates from Al Viro: "Automount wart removal A bunch of odd boilerplate gone from instances - the reason for those was the need to protect the yet-to-be-attched mount from mark_mounts_for_expiry() deciding to take it out. But that's easy to detect and take care of in mark_mounts_for_expiry() itself; no need to have every instance simulate mount being busy by grabbing an extra reference to it, with finish_automount() undoing that once it attaches that mount. Should've done it that way from the very beginning... This is a flagday change, thankfully there are very few instances. vfs_submount() is gone - its sole remaining user (trace_automount) had been switched to saner primitives" * tag 'pull-automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: kill vfs_submount() saner calling conventions for ->d_automount()
2025-05-26Merge tag 'xfs-merge-6.16' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds
Pull xfs updates from Carlos Maiolino: - Atomic writes for XFS - Remove experimental warnings for pNFS, scrub and parent pointers * tag 'xfs-merge-6.16' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (26 commits) xfs: add inode to zone caching for data placement xfs: free the item in xfs_mru_cache_insert on failure xfs: remove the EXPERIMENTAL warning for pNFS xfs: remove some EXPERIMENTAL warnings xfs: Remove deprecated xfs_bufd sysctl parameters xfs: stop using set_blocksize xfs: allow sysadmins to specify a maximum atomic write limit at mount time xfs: update atomic write limits xfs: add xfs_calc_atomic_write_unit_max() xfs: add xfs_file_dio_write_atomic() xfs: commit CoW-based atomic writes atomically xfs: add large atomic writes checks in xfs_direct_write_iomap_begin() xfs: add xfs_atomic_write_cow_iomap_begin() xfs: refine atomic write size check in xfs_file_write_iter() xfs: refactor xfs_reflink_end_cow_extent() xfs: allow block allocator to take an alignment hint xfs: ignore HW which cannot atomic write a single block xfs: add helpers to compute transaction reservation for finishing intent items xfs: add helpers to compute log item overhead xfs: separate out setting buftarg atomic writes limits ...
2025-05-26Merge tag 'for-6.16/block-20250523' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: - ublk updates: - Add support for updating the size of a ublk instance - Zero-copy improvements - Auto-registering of buffers for zero-copy - Series simplifying and improving GET_DATA and request lookup - Series adding quiesce support - Lots of selftests additions - Various cleanups - NVMe updates via Christoph: - add per-node DMA pools and use them for PRP/SGL allocations (Caleb Sander Mateos, Keith Busch) - nvme-fcloop refcounting fixes (Daniel Wagner) - support delayed removal of the multipath node and optionally support the multipath node for private namespaces (Nilay Shroff) - support shared CQs in the PCI endpoint target code (Wilfred Mallawa) - support admin-queue only authentication (Hannes Reinecke) - use the crc32c library instead of the crypto API (Eric Biggers) - misc cleanups (Christoph Hellwig, Marcelo Moreira, Hannes Reinecke, Leon Romanovsky, Gustavo A. R. Silva) - MD updates via Yu: - Fix that normal IO can be starved by sync IO, found by mkfs on newly created large raid5, with some clean up patches for bdev inflight counters - Clean up brd, getting rid of atomic kmaps and bvec poking - Add loop driver specifically for zoned IO testing - Eliminate blk-rq-qos calls with a static key, if not enabled - Improve hctx locking for when a plug has IO for multiple queues pending - Remove block layer bouncing support, which in turn means we can remove the per-node bounce stat as well - Improve blk-throttle support - Improve delay support for blk-throttle - Improve brd discard support - Unify IO scheduler switching. This should also fix a bunch of lockdep warnings we've been seeing, after enabling lockdep support for queue freezing/unfreezeing - Add support for block write streams via FDP (flexible data placement) on NVMe - Add a bunch of block helpers, facilitating the removal of a bunch of duplicated boilerplate code - Remove obsolete BLK_MQ pci and virtio Kconfig options - Add atomic/untorn write support to blktrace - Various little cleanups and fixes * tag 'for-6.16/block-20250523' of git://git.kernel.dk/linux: (186 commits) selftests: ublk: add test for UBLK_F_QUIESCE ublk: add feature UBLK_F_QUIESCE selftests: ublk: add test case for UBLK_U_CMD_UPDATE_SIZE traceevent/block: Add REQ_ATOMIC flag to block trace events ublk: run auto buf unregisgering in same io_ring_ctx with registering io_uring: add helper io_uring_cmd_ctx_handle() ublk: remove io argument from ublk_auto_buf_reg_fallback() ublk: handle ublk_set_auto_buf_reg() failure correctly in ublk_fetch() selftests: ublk: add test for covering UBLK_AUTO_BUF_REG_FALLBACK selftests: ublk: support UBLK_F_AUTO_BUF_REG ublk: support UBLK_AUTO_BUF_REG_FALLBACK ublk: register buffer to local io_uring with provided buf index via UBLK_F_AUTO_BUF_REG ublk: prepare for supporting to register request buffer automatically ublk: convert to refcount_t selftests: ublk: make IO & device removal test more stressful nvme: rename nvme_mpath_shutdown_disk to nvme_mpath_remove_disk nvme: introduce multipath_always_on module param nvme-multipath: introduce delayed removal of the multipath head node nvme-pci: derive and better document max segments limits nvme-pci: use struct_size for allocation struct nvme_dev ...
2025-05-26Merge tag 'vfs-6.16-rc1.super' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs freezing updates from Christian Brauner: "This contains various filesystem freezing related work for this cycle: - Allow the power subsystem to support filesystem freeze for suspend and hibernate. Now all the pieces are in place to actually allow the power subsystem to freeze/thaw filesystems during suspend/resume. Filesystems are only frozen and thawed if the power subsystem does actually own the freeze. If the filesystem is already frozen by the time we've frozen all userspace processes we don't care to freeze it again. That's userspace's job once the process resumes. We only actually freeze filesystems if we absolutely have to and we ignore other failures to freeze. We could bubble up errors and fail suspend/resume if the error isn't EBUSY (aka it's already frozen) but I don't think that this is worth it. Filesystem freezing during suspend/resume is best-effort. If the user has 500 ext4 filesystems mounted and 4 fail to freeze for whatever reason then we simply skip them. What we have now is already a big improvement and let's see how we fare with it before making our lives even harder (and uglier) than we have to. - Allow efivars to support freeze and thaw Allow efivarfs to partake to resync variable state during system hibernation and suspend. Add freeze/thaw support. This is a pretty straightforward implementation. We simply add regular freeze/thaw support for both userspace and the kernel. efivars is the first pseudofilesystem that adds support for filesystem freezing and thawing. The simplicity comes from the fact that we simply always resync variable state after efivarfs has been frozen. It doesn't matter whether that's because of suspend, userspace initiated freeze or hibernation. Efivars is simple enough that it doesn't matter that we walk all dentries. There are no directories and there aren't insane amounts of entries and both freeze/thaw are already heavy-handed operations. If userspace initiated a freeze/thaw cycle they would need CAP_SYS_ADMIN in the initial user namespace (as that's where efivarfs is mounted) so it can't be triggered by random userspace. IOW, we really really don't care" * tag 'vfs-6.16-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: f2fs: fix freezing filesystem during resize kernfs: add warning about implementing freeze/thaw efivarfs: support freeze/thaw power: freeze filesystems during suspend/resume libfs: export find_next_child() super: add filesystem freezing helpers for suspend and hibernate gfs2: pass through holder from the VFS for freeze/thaw super: use common iterator (Part 2) super: use a common iterator (Part 1) super: skip dying superblocks early super: simplify user_get_super() super: remove pointless s_root checks fs: allow all writers to be frozen locking/percpu-rwsem: add freezable alternative to down_read
2025-05-26Merge tag 'vfs-6.16-rc1.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc vfs updates from Christian Brauner: "This contains the usual selections of misc updates for this cycle. Features: - Use folios for symlinks in the page cache FUSE already uses folios for its symlinks. Mirror that conversion in the generic code and the NFS code. That lets us get rid of a few folio->page->folio conversions in this path, and some of the few remaining users of read_cache_page() / read_mapping_page() - Try and make a few filesystem operations killable on the VFS inode->i_mutex level - Add sysctl vfs_cache_pressure_denom for bulk file operations Some workloads need to preserve more dentries than we currently allow through out sysctl interface A HDFS servers with 12 HDDs per server, on a HDFS datanode startup involves scanning all files and caching their metadata (including dentries and inodes) in memory. Each HDD contains approximately 2 million files, resulting in a total of ~20 million cached dentries after initialization To minimize dentry reclamation, they set vfs_cache_pressure to 1. Despite this configuration, memory pressure conditions can still trigger reclamation of up to 50% of cached dentries, reducing the cache from 20 million to approximately 10 million entries. During the subsequent cache rebuild period, any HDFS datanode restart operation incurs substantial latency penalties until full cache recovery completes To maintain service stability, more dentries need to be preserved during memory reclamation. The current minimum reclaim ratio (1/100 of total dentries) remains too aggressive for such workload. This patch introduces vfs_cache_pressure_denom for more granular cache pressure control The configuration [vfs_cache_pressure=1, vfs_cache_pressure_denom=10000] effectively maintains the full 20 million dentry cache under memory pressure, preventing datanode restart performance degradation - Avoid some jumps in inode_permission() using likely()/unlikely() - Avid a memory access which is most likely a cache miss when descending into devcgroup_inode_permission() - Add fastpath predicts for stat() and fdput() - Anonymous inodes currently don't come with a proper mode causing issues in the kernel when we want to add useful VFS debug assert. Fix that by giving them a proper mode and masking it off when we report it to userspace which relies on them not having any mode - Anonymous inodes currently allow to change inode attributes because the VFS falls back to simple_setattr() if i_op->setattr isn't implemented. This means the ownership and mode for every single user of anon_inode_inode can be changed. Block that as it's either useless or actively harmful. If specific ownership is needed the respective subsystem should allocate anonymous inodes from their own private superblock - Raise SB_I_NODEV and SB_I_NOEXEC on the anonymous inode superblock - Add proper tests for anonymous inode behavior - Make it easy to detect proper anonymous inodes and to ensure that we can detect them in codepaths such as readahead() Cleanups: - Port pidfs to the new anon_inode_{g,s}etattr() helpers - Try to remove the uselib() system call - Add unlikely branch hint return path for poll - Add unlikely branch hint on return path for core_sys_select - Don't allow signals to interrupt getdents copying for fuse - Provide a size hint to dir_context for during readdir() - Use writeback_iter directly in mpage_writepages - Update compression and mtime descriptions in initramfs documentation - Update main netfs API document - Remove useless plus one in super_cache_scan() - Remove unnecessary NULL-check guards during setns() - Add separate separate {get,put}_cgroup_ns no-op cases Fixes: - Fix typo in root= kernel parameter description - Use KERN_INFO for infof()|info_plog()|infofc() - Correct comments of fs_validate_description() - Mark an unlikely if condition with unlikely() in vfs_parse_monolithic_sep() - Delete macro fsparam_u32hex() - Remove unused and problematic validate_constant_table() - Fix potential unsigned integer underflow in fs_name() - Make file-nr output the total allocated file handles" * tag 'vfs-6.16-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (43 commits) fs: Pass a folio to page_put_link() nfs: Use a folio in nfs_get_link() fs: Convert __page_get_link() to use a folio fs/read_write: make default_llseek() killable fs/open: make do_truncate() killable fs/open: make chmod_common() and chown_common() killable include/linux/fs.h: add inode_lock_killable() readdir: supply dir_context.count as readdir buffer size hint vfs: Add sysctl vfs_cache_pressure_denom for bulk file operations fuse: don't allow signals to interrupt getdents copying Documentation: fix typo in root= kernel parameter description include/cgroup: separate {get,put}_cgroup_ns no-op case kernel/nsproxy: remove unnecessary guards fs: use writeback_iter directly in mpage_writepages fs: remove useless plus one in super_cache_scan() fs: add S_ANON_INODE fs: remove uselib() system call device_cgroup: avoid access to ->i_rdev in the common case in devcgroup_inode_permission() fs/fs_parse: Remove unused and problematic validate_constant_table() fs: touch up predicts in inode_permission() ...
2025-05-26Merge tag 'vfs-6.16-rc1.writepage' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull final writepage conversion from Christian Brauner: "This converts vboxfs from ->writepage() to ->writepages(). This was the last user of the ->writepage() method. So remove ->writepage() completely and all references to it" * tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: Remove aops->writepage mm: Remove swap_writepage() and shmem_writepage() ttm: Call shmem_writeout() from ttm_backup_backup_page() i915: Use writeback_iter() shmem: Add shmem_writeout() writeback: Remove writeback_use_writepage() migrate: Remove call to ->writepage vboxsf: Convert to writepages 9p: Add a migrate_folio method
2025-05-25Disable FOP_DONTCACHE for now due to bugsLinus Torvalds
This is kind of last-minute, but Al Viro reported that the new FOP_DONTCACHE flag causes memory corruption due to use-after-free issues. This was triggered by commit 974c5e6139db ("xfs: flag as supporting FOP_DONTCACHE"), but that is not the underlying bug - it is just the first user of the flag. Vlastimil Babka suspects the underlying problem stems from the folio_end_writeback() logic introduced in commit fb7d3bc414939 ("mm/filemap: drop streaming/uncached pages when writeback completes"). The most straightforward fix would be to just revert the commit that exposed this, but Matthew Wilcox points out that other filesystems are also starting to enable the FOP_DONTCACHE logic, so this instead disables that bit globally for now. The fix will hopefully end up being trivial and we can just re-enable this logic after more testing, but until such a time we'll have to disable the new FOP_DONTCACHE flag. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Link: https://lore.kernel.org/all/20250525083209.GS2023217@ZenIV/ Triggered-by: 974c5e6139db ("xfs: flag as supporting FOP_DONTCACHE") Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-05-22mm: remove WARN_ON_ONCE() in file_has_valid_mmap_hooks()Lorenzo Stoakes
Having encountered a trinity report in linux-next (Linked in the 'Closes' tag) it appears that there are legitimate situations where a file-backed mapping can be acquired but no file->f_op->mmap or file->f_op->mmap_prepare is set, at which point do_mmap() should simply error out with -ENODEV. Since previously we did not warn in this scenario and it appears we rely upon this, restore this situation, while retaining a WARN_ON_ONCE() for the case where both are set, which is absolutely incorrect and must be addressed and thus always requires a warning. If further work is required to chase down precisely what is causing this, then we can later restore this, but it makes no sense to hold up this series to do so, as this is existing and apparently expected behaviour. Link: https://lkml.kernel.org/r/20250514084024.29148-1-lorenzo.stoakes@oracle.com Fixes: c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file callback") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202505141434.96ce5e5d-lkp@intel.com Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Acked-by: David Hildenbrand <david@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-15include/linux/fs.h: add inode_lock_killable()Max Kellermann
Prepare for making inode operations killable while they're waiting for the lock. Signed-off-by: Max Kellermann <max.kellermann@ionos.com> Link: https://lore.kernel.org/20250513150327.1373061-1-max.kellermann@ionos.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-05-15readdir: supply dir_context.count as readdir buffer size hintMiklos Szeredi
This is a preparation for large readdir buffers in fuse. Simply setting the fuse buffer size to the userspace buffer size should work, the record sizes are similar (fuse's is slightly larger than libc's, so no overflow should ever happen). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Jaco Kroon <jaco@uls.co.za> Link: https://lore.kernel.org/20250513151012.1476536-1-mszeredi@redhat.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-05-15fuse: don't allow signals to interrupt getdents copyingMiklos Szeredi
When getting the directory contents, the entries are first fetched to a kernel buffer, then they are copied to userspace with dir_emit(). This second phase is non-blocking as long as the userspace buffer is not paged out, making it interruptible makes zero sense. Overload d_type as flags, since it only uses 4 bits from 32. Reviewed-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/20250513112335.1473177-1-mszeredi@redhat.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-05-13mm: introduce new .mmap_prepare() file callbackLorenzo Stoakes
Patch series "eliminate mmap() retry merge, add .mmap_prepare hook", v2. During the mmap() of a file-backed mapping, we invoke the underlying driver file's mmap() callback in order to perform driver/file system initialisation of the underlying VMA. This has been a source of issues in the past, including a significant security concern relating to unwinding of error state discovered by Jann Horn, as fixed in commit 5de195060b2e ("mm: resolve faulty mmap_region() error path behaviour") which performed the recent, significant, rework of mmap() as a whole. However, we have had a fly in the ointment remain - drivers have a great deal of freedom in the .mmap() hook to manipulate VMA state (as well as page table state). This can be problematic, as we can no longer reason sensibly about VMA state once the call is complete (the ability to do - anything - here does rather interfere with that). In addition, callers may choose to do odd or unusual things which might interfere with subsequent steps in the mmap() process, and it may do so and then raise an error, requiring very careful unwinding of state about which we can make no assumptions. Rather than providing such an open-ended interface, this series provides an alternative, far more restrictive one - we expose a whitelist of fields which can be adjusted by the driver, along with immutable state upon which the driver can make such decisions: struct vm_area_desc { /* Immutable state. */ struct mm_struct *mm; unsigned long start; unsigned long end; /* Mutable fields. Populated with initial state. */ pgoff_t pgoff; struct file *file; vm_flags_t vm_flags; pgprot_t page_prot; /* Write-only fields. */ const struct vm_operations_struct *vm_ops; void *private_data; }; The mmap logic then updates the state used to either merge with a VMA or establish a new VMA based upon this logic. This is achieved via new file hook .mmap_prepare(), which is, importantly, invoked very early on in the mmap() process. If an error arises, we can very simply abort the operation with very little unwinding of state required. The existing logic contains another, related, peccadillo - since the .mmap() callback might do anything, it may also cause a previously unmergeable VMA to become mergeable with adjacent VMAs. Right now the logic will retry a merge like this only if the driver changes VMA flags, and changes them in such a way that a merge might succeed (that is, the flags are not 'special', that is do not contain any of the flags specified in VM_SPECIAL). This has also been the source of a great deal of pain - it's hard to reason about an .mmap() callback that might do - anything - but it's also hard to reason about setting up a VMA and writing to the maple tree, only to do it again utilising a great deal of shared state. Since .mmap_prepare() sets fields before the first merge is even attempted, the use of this callback obviates the need for this retry merge logic. A driver may only specify .mmap_prepare() or the deprecated .mmap() callback. In future we may add futher callbacks beyond .mmap_prepare() to faciliate all use cass as we convert drivers. In researching this change, I examined every .mmap() callback, and discovered only a very few that set VMA state in such a way that a. the VMA flags changed and b. this would be mergeable. In the majority of cases, it turns out that drivers are mapping kernel memory and thus ultimately set VM_PFNMAP, VM_MIXEDMAP, or other unmergeable VM_SPECIAL flags. Of those that remain I identified a number of cases which are only applicable in DAX, setting the VM_HUGEPAGE flag: * dax_mmap() * erofs_file_mmap() * ext4_file_mmap() * xfs_file_mmap() For this remerge to not occur and to impact users, each of these cases would require a user to mmap() files using DAX, in parts, immediately adjacent to one another. This is a very unlikely usecase and so it does not appear to be worthwhile to adjust this functionality accordingly. We can, however, very quickly do so if needed by simply adding an .mmap_prepare() callback to these as required. There are two further non-DAX cases I idenitfied: * orangefs_file_mmap() - Clears VM_RAND_READ if set, replacing with VM_SEQ_READ. * usb_stream_hwdep_mmap() - Sets VM_DONTDUMP. Both of these cases again seem very unlikely to be mmap()'d immediately adjacent to one another in a fashion that would result in a merge. Finally, we are left with a viable case: * secretmem_mmap() - Set VM_LOCKED, VM_DONTDUMP. This is viable enough that the mm selftests trigger the logic as a matter of course. Therefore, this series replace the .secretmem_mmap() hook with .secret_mmap_prepare(). This patch (of 3): Provide a means by which drivers can specify which fields of those permitted to be changed should be altered to prior to mmap()'ing a range (which may either result from a merge or from mapping an entirely new VMA). Doing so is substantially safer than the existing .mmap() calback which provides unrestricted access to the part-constructed VMA and permits drivers and file systems to do 'creative' things which makes it hard to reason about the state of the VMA after the function returns. The existing .mmap() callback's freedom has caused a great deal of issues, especially in error handling, as unwinding the mmap() state has proven to be non-trivial and caused significant issues in the past, for instance those addressed in commit 5de195060b2e ("mm: resolve faulty mmap_region() error path behaviour"). It also necessitates a second attempt at merge once the .mmap() callback has completed, which has caused issues in the past, is awkward, adds overhead and is difficult to reason about. The .mmap_prepare() callback eliminates this requirement, as we can update fields prior to even attempting the first merge. It is safer, as we heavily restrict what can actually be modified, and being invoked very early in the mmap() process, error handling can be performed safely with very little unwinding of state required. The .mmap_prepare() and deprecated .mmap() callbacks are mutually exclusive, so we permit only one to be invoked at a time. Update vma userland test stubs to account for changes. Link: https://lkml.kernel.org/r/cover.1746792520.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/adb36a7c4affd7393b2fc4b54cc5cfe211e41f71.1746792520.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-09super: add filesystem freezing helpers for suspend and hibernateChristian Brauner
Allow the power subsystem to support filesystem freeze for suspend and hibernate. For some kernel subsystems it is paramount that they are guaranteed that they are the owner of the freeze to avoid any risk of deadlocks. This is the case for the power subsystem. Enable it to recognize whether it did actually freeze the filesystem. If userspace has 10 filesystems and suspend/hibernate manges to freeze 5 and then fails on the 6th for whatever odd reason (current or future) then power needs to undo the freeze of the first 5 filesystems. It can't just walk the list again because while it's unlikely that a new filesystem got added in the meantime it still cannot tell which filesystems the power subsystem actually managed to get a freeze reference count on that needs to be dropped during thaw. There's various ways out of this ugliness. For example, record the filesystems the power subsystem managed to freeze on a temporary list in the callbacks and then walk that list backwards during thaw to undo the freezing or make sure that the power subsystem just actually exclusively freezes things it can freeze and marking such filesystems as being owned by power for the duration of the suspend or resume cycle. I opted for the latter as that seemed the clean thing to do even if it means more code changes. If hibernation races with filesystem freezing (e.g. DM reconfiguration), then hibernation need not freeze a filesystem because it's already frozen but userspace may thaw the filesystem before hibernation actually happens. If the race happens the other way around, DM reconfiguration may unexpectedly fail with EBUSY. So allow FREEZE_EXCL to nest with other holders. An exclusive freezer cannot be undone by any of the other concurrent freezers. Link: https://lore.kernel.org/r/20250329-work-freeze-v2-6-a47af37ecc3d@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-05-07fs: add atomic write unit max opt to statxJohn Garry
XFS will be able to support large atomic writes (atomic write > 1x block) in future. This will be achieved by using different operating methods, depending on the size of the write. Specifically a new method of operation based in FS atomic extent remapping will be supported in addition to the current HW offload-based method. The FS method will generally be appreciably slower performing than the HW-offload method. However the FS method will be typically able to contribute to achieving a larger atomic write unit max limit. XFS will support a hybrid mode, where HW offload method will be used when possible, i.e. HW offload is used when the length of the write is supported, and for other times FS-based atomic writes will be used. As such, there is an atomic write length at which the user may experience appreciably slower performance. Advertise this limit in a new statx field, stx_atomic_write_unit_max_opt. When zero, it means that there is no such performance boundary. Masks STATX{_ATTR}_WRITE_ATOMIC can be used to get this new field. This is ok for older kernels which don't support this new field, as they would report 0 in this field (from zeroing in cp_statx()) already. Furthermore those older kernels don't support large atomic writes - apart from block fops, but there would be consistent performance there for atomic writes in range [unit min, unit max]. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Acked-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: John Garry <john.g.garry@oracle.com>
2025-05-06kill vfs_submount()Al Viro
The last remaining user of vfs_submount() (tracefs) is easy to convert to fs_context_for_submount(); do that and bury that thing, along with SB_SUBMOUNT Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-05-06fs: add a write stream field to the kiocbChristoph Hellwig
Prepare for io_uring passthrough of write streams. The write stream field in the kiocb structure fits into an existing 2-byte hole, so its size is not changed. Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com> Link: https://lore.kernel.org/r/20250506121732.8211-2-joshi.k@samsung.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-21fs: add S_ANON_INODEChristian Brauner
This makes it easy to detect proper anonymous inodes and to ensure that we can detect them in codepaths such as readahead(). Readahead on anonymous inodes didn't work because they didn't have a proper mode. Now that they have we need to retain EINVAL being returned otherwise LTP will fail. We also need to ensure that ioctls aren't simply fired like they are for regular files so things like inotify inodes continue to correctly call their own ioctl handlers as in [1]. Reported-by: Xilin Wu <sophon@radxa.com> Link: https://lore.kernel.org/3A9139D5CD543962+89831381-31b9-4392-87ec-a84a5b3507d8@radxa.com [1] Link: https://lore.kernel.org/7a1a7076-ff6b-4cb0-94e7-7218a0a44028@sirena.org.uk Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-07super: use common iterator (Part 2)Christian Brauner
Use a common iterator for all callbacks. We could go for something even more elaborate (advance step-by-step similar to iov_iter) but I really don't think this is warranted. Link: https://lore.kernel.org/r/20250329-work-freeze-v2-5-a47af37ecc3d@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-07super: use a common iterator (Part 1)Christian Brauner
Use a common iterator for all callbacks. Link: https://lore.kernel.org/r/20250329-work-freeze-v2-4-a47af37ecc3d@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-07fs: allow all writers to be frozenJames Bottomley
During freeze/thaw we need to be able to freeze all writers during suspend/hibernate. Otherwise tasks such as systemd-journald that mmap a file and write to it will not be frozen after we've already frozen the filesystem. This has some risk of not being able to freeze processes in case a process has acquired SB_FREEZE_PAGEFAULT under mmap_sem or SB_FREEZE_INTERNAL under some other filesytem specific lock. If the filesystem is frozen, a task can block on the frozen filesystem with e.g., mmap_sem held. If some other task then blocks on grabbing that mmap_sem, hibernation ill fail because it is unable to hibernate a task holding mmap_sem. This could be fixed by making a range of filesystem related locks use freezable sleeping. That's impractical and not warranted just for suspend/hibernate. Assume that this is an infrequent problem and we've given userspace a way to skip filesystem freezing through a sysfs file. Link: https://lore.kernel.org/r/20250402-work-freeze-v2-2-6719a97b52ac@kernel.org Link: https://lore.kernel.org/r/20250327140613.25178-3-James.Bottomley@HansenPartnership.com [brauner: make all freeze levels set TASK_FREEZABLE and rewrite commit message] Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-04-07fs: Remove aops->writepageMatthew Wilcox (Oracle)
All callers and implementations are now removed, so remove the operation and update the documentation to match. Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Link: https://lore.kernel.org/r/20250402150005.2309458-10-willy@infradead.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-27Merge tag 'ext4-for_linus-6.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Ext4 bug fixes and cleanups, including: - hardening against maliciously fuzzed file systems - backwards compatibility for the brief period when we attempted to ignore zero-width characters - avoid potentially BUG'ing if there is a file system corruption found during the file system unmount - fix free space reporting by statfs when project quotas are enabled and the free space is less than the remaining project quota Also improve performance when replaying a journal with a very large number of revoke records (applicable for Lustre volumes)" * tag 'ext4-for_linus-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (71 commits) ext4: fix OOB read when checking dotdot dir ext4: on a remount, only log the ro or r/w state when it has changed ext4: correct the error handle in ext4_fallocate() ext4: Make sb update interval tunable ext4: avoid journaling sb update on error if journal is destroying ext4: define ext4_journal_destroy wrapper ext4: hash: simplify kzalloc(n * 1, ...) to kzalloc(n, ...) jbd2: add a missing data flush during file and fs synchronization ext4: don't over-report free space or inodes in statvfs ext4: clear DISCARD flag if device does not support discard jbd2: remove jbd2_journal_unfile_buffer() ext4: reorder capability check last ext4: update the comment about mb_optimize_scan jbd2: fix off-by-one while erasing journal ext4: remove references to bh->b_page ext4: goto right label 'out_mmap_sem' in ext4_setattr() ext4: fix out-of-bound read in ext4_xattr_inode_dec_ref_all() ext4: introduce ITAIL helper jbd2: remove redundant function jbd2_journal_has_csum_v2or3_feature ext4: remove redundant function ext4_has_metadata_csum ...
2025-03-24Merge tag 'vfs-6.15-rc1.pagesize' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs pagesize updates from Christian Brauner: "This enables block sizes greater than the page size for block devices. With this we can start supporting block devices with logical block sizes larger than 4k. It also allows to lift the device cache sector size support to 64k. This allows filesystems which can use larger sector sizes up to 64k to ensure that the filesystem will not generate writes that are smaller than the specified sector size" * tag 'vfs-6.15-rc1.pagesize' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: bdev: add back PAGE_SIZE block size validation for sb_set_blocksize() bdev: use bdev_io_min() for statx block size block/bdev: lift block size restrictions to 64k block/bdev: enable large folio support for large logical block sizes fs/buffer fs/mpage: remove large folio restriction fs/mpage: use blocks_per_folio instead of blocks_per_page fs/mpage: avoid negative shift for large blocksize fs/buffer: remove batching from async read fs/buffer: simplify block_read_full_folio() with bh_offset()
2025-03-24Merge tag 'vfs-6.15-rc1.mount.namespace' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs mount namespace updates from Christian Brauner: "This expands the ability of anonymous mount namespaces: - Creating detached mounts from detached mounts Currently, detached mounts can only be created from attached mounts. This limitaton prevents various use-cases. For example, the ability to mount a subdirectory without ever having to make the whole filesystem visible first. The current permission modelis: (1) Check that the caller is privileged over the owning user namespace of it's current mount namespace. (2) Check that the caller is located in the mount namespace of the mount it wants to create a detached copy of. While it is not strictly necessary to do it this way it is consistently applied in the new mount api. This model will also be used when allowing the creation of detached mount from another detached mount. The (1) requirement can simply be met by performing the same check as for the non-detached case, i.e., verify that the caller is privileged over its current mount namespace. To meet the (2) requirement it must be possible to infer the origin mount namespace that the anonymous mount namespace of the detached mount was created from. The origin mount namespace of an anonymous mount is the mount namespace that the mounts that were copied into the anonymous mount namespace originate from. In order to check the origin mount namespace of an anonymous mount namespace the sequence number of the original mount namespace is recorded in the anonymous mount namespace. With this in place it is possible to perform an equivalent check (2') to (2). The origin mount namespace of the anonymous mount namespace must be the same as the caller's mount namespace. To establish this the sequence number of the caller's mount namespace and the origin sequence number of the anonymous mount namespace are compared. The caller is always located in a non-anonymous mount namespace since anonymous mount namespaces cannot be setns()ed into. The caller's mount namespace will thus always have a valid sequence number. The owning namespace of any mount namespace, anonymous or non-anonymous, can never change. A mount attached to a non-anonymous mount namespace can never change mount namespace. If the sequence number of the non-anonymous mount namespace and the origin sequence number of the anonymous mount namespace match, the owning namespaces must match as well. Hence, the capability check on the owning namespace of the caller's mount namespace ensures that the caller has the ability to copy the mount tree. - Allow mount detached mounts on detached mounts Currently, detached mounts can only be mounted onto attached mounts. This limitation makes it impossible to assemble a new private rootfs and move it into place. Instead, a detached tree must be created, attached, then mounted open and then either moved or detached again. Lift this restriction. In order to allow mounting detached mounts onto other detached mounts the same permission model used for creating detached mounts from detached mounts can be used (cf. above). Allowing to mount detached mounts onto detached mounts leaves three cases to consider: (1) The source mount is an attached mount and the target mount is a detached mount. This would be equivalent to moving a mount between different mount namespaces. A caller could move an attached mount to a detached mount. The detached mount can now be freely attached to any mount namespace. This changes the current delegatioh model significantly for no good reason. So this will fail. (2) Anonymous mount namespaces are always attached fully, i.e., it is not possible to only attach a subtree of an anoymous mount namespace. This simplifies the implementation and reasoning. Consequently, if the anonymous mount namespace of the source detached mount and the target detached mount are the identical the mount request will fail. (3) The source mount's anonymous mount namespace is different from the target mount's anonymous mount namespace. In this case the source anonymous mount namespace of the source mount tree must be freed after its mounts have been moved to the target anonymous mount namespace. The source anonymous mount namespace must be empty afterwards. By allowing to mount detached mounts onto detached mounts a caller may do the following: fd_tree1 = open_tree(-EBADF, "/mnt", OPEN_TREE_CLONE) fd_tree2 = open_tree(-EBADF, "/tmp", OPEN_TREE_CLONE) fd_tree1 and fd_tree2 refer to two different detached mount trees that belong to two different anonymous mount namespace. It is important to note that fd_tree1 and fd_tree2 both refer to the root of their respective anonymous mount namespaces. By allowing to mount detached mounts onto detached mounts the caller may now do: move_mount(fd_tree1, "", fd_tree2, "", MOVE_MOUNT_F_EMPTY_PATH | MOVE_MOUNT_T_EMPTY_PATH) This will cause the detached mount referred to by fd_tree1 to be mounted on top of the detached mount referred to by fd_tree2. Thus, the detached mount fd_tree1 is moved from its separate anonymous mount namespace into fd_tree2's anonymous mount namespace. It also means that while fd_tree2 continues to refer to the root of its respective anonymous mount namespace fd_tree1 doesn't anymore. This has the consequence that only fd_tree2 can be moved to another anonymous or non-anonymous mount namespace. Moving fd_tree1 will now fail as fd_tree1 doesn't refer to the root of an anoymous mount namespace anymore. Now fd_tree1 and fd_tree2 refer to separate detached mount trees referring to the same anonymous mount namespace. This is conceptually fine. The new mount api does allow for this to happen already via: mount -t tmpfs tmpfs /mnt mkdir -p /mnt/A mount -t tmpfs tmpfs /mnt/A fd_tree3 = open_tree(-EBADF, "/mnt", OPEN_TREE_CLONE | AT_RECURSIVE) fd_tree4 = open_tree(-EBADF, "/mnt/A", 0) Both fd_tree3 and fd_tree4 refer to two different detached mount trees but both detached mount trees refer to the same anonymous mount namespace. An as with fd_tree1 and fd_tree2, only fd_tree3 may be moved another mount namespace as fd_tree3 refers to the root of the anonymous mount namespace just while fd_tree4 doesn't. However, there's an important difference between the fd_tree3/fd_tree4 and the fd_tree1/fd_tree2 example. Closing fd_tree4 and releasing the respective struct file will have no further effect on fd_tree3's detached mount tree. However, closing fd_tree3 will cause the mount tree and the respective anonymous mount namespace to be destroyed causing the detached mount tree of fd_tree4 to be invalid for further mounting. By allowing to mount detached mounts on detached mounts as in the fd_tree1/fd_tree2 example both struct files will affect each other. Both fd_tree1 and fd_tree2 refer to struct files that have FMODE_NEED_UNMOUNT set. To handle this we use the fact that @fd_tree1 will have a parent mount once it has been attached to @fd_tree2. When dissolve_on_fput() is called the mount that has been passed in will refer to the root of the anonymous mount namespace. If it doesn't it would mean that mounts are leaked. So before allowing to mount detached mounts onto detached mounts this would be a bug. Now that detached mounts can be mounted onto detached mounts it just means that the mount has been attached to another anonymous mount namespace and thus dissolve_on_fput() must not unmount the mount tree or free the anonymous mount namespace as the file referring to the root of the namespace hasn't been closed yet. If it had been closed yet it would be obvious because the mount namespace would be NULL, i.e., the @fd_tree1 would have already been unmounted. If @fd_tree1 hasn't been unmounted yet and has a parent mount it is safe to skip any cleanup as closing @fd_tree2 will take care of all cleanup operations. - Allow mount propagation for detached mount trees In commit ee2e3f50629f ("mount: fix mounting of detached mounts onto targets that reside on shared mounts") I fixed a bug where propagating the source mount tree of an anonymous mount namespace into a target mount tree of a non-anonymous mount namespace could be used to trigger an integer overflow in the non-anonymous mount namespace causing any new mounts to fail. The cause of this was that the propagation algorithm was unable to recognize mounts from the source mount tree that were already propagated into the target mount tree and then reappeared as propagation targets when walking the destination propagation mount tree. When fixing this I disabled mount propagation into anonymous mount namespaces. Make it possible for anonymous mount namespace to receive mount propagation events correctly. This is now also a correctness issue now that we allow mounting detached mount trees onto detached mount trees. Mark the source anonymous mount namespace with MNTNS_PROPAGATING indicating that all mounts belonging to this mount namespace are currently in the process of being propagated and make the propagation algorithm discard those if they appear as propagation targets" * tag 'vfs-6.15-rc1.mount.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (21 commits) selftests: test subdirectory mounting selftests: add test for detached mount tree propagation fs: namespace: fix uninitialized variable use mount: handle mount propagation for detached mount trees fs: allow creating detached mounts from fsmount() file descriptors selftests: seventh test for mounting detached mounts onto detached mounts selftests: sixth test for mounting detached mounts onto detached mounts selftests: fifth test for mounting detached mounts onto detached mounts selftests: fourth test for mounting detached mounts onto detached mounts selftests: third test for mounting detached mounts onto detached mounts selftests: second test for mounting detached mounts onto detached mounts selftests: first test for mounting detached mounts onto detached mounts fs: mount detached mounts onto detached mounts fs: support getname_maybe_null() in move_mount() selftests: create detached mounts from detached mounts fs: create detached mounts from detached mounts fs: add may_copy_tree() fs: add fastpath for dissolve_on_fput() fs: add assert for move_mount() fs: add mnt_ns_empty() helper ...
2025-03-24Merge tag 'vfs-6.15-rc1.async.dir' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs async dir updates from Christian Brauner: "This contains cleanups that fell out of the work from async directory handling: - Change kern_path_locked() and user_path_locked_at() to never return a negative dentry. This simplifies the usability of these helpers in various places - Drop d_exact_alias() from the remaining place in NFS where it is still used. This also allows us to drop the d_exact_alias() helper completely - Drop an unnecessary call to fh_update() from nfsd_create_locked() - Change i_op->mkdir() to return a struct dentry Change vfs_mkdir() to return a dentry provided by the filesystems which is hashed and positive. This allows us to reduce the number of cases where the resulting dentry is not positive to very few cases. The code in these places becomes simpler and easier to understand. - Repack DENTRY_* and LOOKUP_* flags" * tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: doc: fix inline emphasis warning VFS: Change vfs_mkdir() to return the dentry. nfs: change mkdir inode_operation to return alternate dentry if needed. fuse: return correct dentry for ->mkdir ceph: return the correct dentry on mkdir hostfs: store inode in dentry after mkdir if possible. Change inode_operations.mkdir to return struct dentry * nfsd: drop fh_update() from S_IFDIR branch of nfsd_create_locked() nfs/vfs: discard d_exact_alias() VFS: add common error checks to lookup_one_qstr_excl() VFS: change kern_path_locked() and user_path_locked_at() to never return negative dentry VFS: repack LOOKUP_ bit flags. VFS: repack DENTRY_ flags.
2025-03-24Merge tag 'vfs-6.15-rc1.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc vfs updates from Christian Brauner: "Features: - Add CONFIG_DEBUG_VFS infrastucture: - Catch invalid modes in open - Use the new debug macros in inode_set_cached_link() - Use debug-only asserts around fd allocation and install - Place f_ref to 3rd cache line in struct file to resolve false sharing Cleanups: - Start using anon_inode_getfile_fmode() helper in various places - Don't take f_lock during SEEK_CUR if exclusion is guaranteed by f_pos_lock - Add unlikely() to kcmp() - Remove legacy ->remount_fs method from ecryptfs after port to the new mount api - Remove invalidate_inodes() in favour of evict_inodes() - Simplify ep_busy_loopER by removing unused argument - Avoid mmap sem relocks when coredumping with many missing pages - Inline getname() - Inline new_inode_pseudo() and de-staticize alloc_inode() - Dodge an atomic in putname if ref == 1 - Consistently deref the files table with rcu_dereference_raw() - Dedup handling of struct filename init and refcounts bumps - Use wq_has_sleeper() in end_dir_add() - Drop the lock trip around I_NEW wake up in evict() - Load the ->i_sb pointer once in inode_sb_list_{add,del} - Predict not reaching the limit in alloc_empty_file() - Tidy up do_sys_openat2() with likely/unlikely - Call inode_sb_list_add() outside of inode hash lock - Sort out fd allocation vs dup2 race commentary - Turn page_offset() into a wrapper around folio_pos() - Remove locking in exportfs around ->get_parent() call - try_lookup_one_len() does not need any locks in autofs - Fix return type of several functions from long to int in open - Fix return type of several functions from long to int in ioctls Fixes: - Fix watch queue accounting mismatch" * tag 'vfs-6.15-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits) fs: sort out fd allocation vs dup2 race commentary, take 2 fs: call inode_sb_list_add() outside of inode hash lock fs: tidy up do_sys_openat2() with likely/unlikely fs: predict not reaching the limit in alloc_empty_file() fs: load the ->i_sb pointer once in inode_sb_list_{add,del} fs: drop the lock trip around I_NEW wake up in evict() fs: use wq_has_sleeper() in end_dir_add() VFS/autofs: try_lookup_one_len() does not need any locks fs: dedup handling of struct filename init and refcounts bumps fs: consistently deref the files table with rcu_dereference_raw() exportfs: remove locking around ->get_parent() call. fs: use debug-only asserts around fd allocation and install fs: dodge an atomic in putname if ref == 1 vfs: Remove invalidate_inodes() ecryptfs: remove NULL remount_fs from super_operations watch_queue: fix pipe accounting mismatch fs: place f_ref to 3rd cache line in struct file to resolve false sharing epoll: simplify ep_busy_loop by removing always 0 argument fs: Turn page_offset() into a wrapper around folio_pos() kcmp: improve performance adding an unlikely hint to task comparisons ...
2025-03-24Merge tag 'vfs-6.15-rc1.mount.api' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs mount API updates from Christian Brauner: "This converts the remaining pseudo filesystems to the new mount api. The sysv conversion is a bit gratuitous because we remove sysv in another pull request. But if we have to revert the removal we at least will have it converted to the new mount api already" * tag 'vfs-6.15-rc1.mount.api' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: sysv: convert sysv to use the new mount api vfs: remove some unused old mount api code devtmpfs: replace ->mount with ->get_tree in public instance vfs: Convert devpts to use the new mount API pstore: convert to the new mount API
2025-03-18fs: dedup handling of struct filename init and refcounts bumpsMateusz Guzik
No functional changes. Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20250313142744.1323281-1-mjguzik@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-07bdev: add back PAGE_SIZE block size validation for sb_set_blocksize()Luis Chamberlain
The commit titled "block/bdev: lift block size restrictions to 64k" lifted the block layer's max supported block size to 64k inside the helper blk_validate_block_size() now that we support large folios. However in lifting the block size we also removed the silly use cases many filesystems have to use sb_set_blocksize() to *verify* that the block size <= PAGE_SIZE. The call to sb_set_blocksize() was used to check the block size <= PAGE_SIZE since historically we've always supported userspace to create for example 64k block size filesystems even on 4k page size systems, but what we didn't allow was mounting them. Older filesystems have been using the check with sb_set_blocksize() for years. While, we could argue that such checks should be filesystem specific, there are much more users of sb_set_blocksize() than LBS enabled filesystem on upstream, so just do the easier thing and bring back the PAGE_SIZE check for sb_set_blocksize() users and only skip it for LBS enabled filesystems. This will ensure that tests such as generic/466 when run in a loop against say, ext4, won't try to try to actually mount a filesystem with a block size larger than your filesystem supports given your PAGE_SIZE and in the worst case crash. Cc: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20250307020403.3068567-1-mcgrof@kernel.org Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-05VFS: Change vfs_mkdir() to return the dentry.NeilBrown
vfs_mkdir() does not guarantee to leave the child dentry hashed or make it positive on success, and in many such cases the filesystem had to use a different dentry which it can now return. This patch changes vfs_mkdir() to return the dentry provided by the filesystems which is hashed and positive when provided. This reduces the number of cases where the resulting dentry is not positive to a handful which don't deserve extra efforts. The only callers of vfs_mkdir() which are interested in the resulting inode are in-kernel filesystem clients: cachefiles, nfsd, smb/server. The only filesystems that don't reliably provide the inode are: - kernfs, tracefs which these clients are unlikely to be interested in - cifs in some configurations would need to do a lookup to find the created inode, but doesn't. cifs cannot be exported via NFS, is unlikely to be used by cachefiles, and smb/server only has a soft requirement for the inode, so this is unlikely to be a problem in practice. - hostfs, nfs, cifs may need to do a lookup (rarely for NFS) and it is possible for a race to make that lookup fail. Actual failure is unlikely and providing callers handle negative dentries graceful they will fail-safe. So this patch removes the lookup code in nfsd and smb/server and adjusts them to fail safe if a negative dentry is provided: - cache-files already fails safe by restarting the task from the top - it still does with this change, though it no longer calls cachefiles_put_directory() as that will crash if the dentry is negative. - nfsd reports "Server-fault" which it what it used to do if the lookup failed. This will never happen on any file-systems that it can actually export, so this is of no consequence. I removed the fh_update() call as that is not needed and out-of-place. A subsequent nfsd_create_setattr() call will call fh_update() when needed. - smb/server only wants the inode to call ksmbd_smb_inherit_owner() which updates ->i_uid (without calling notify_change() or similar) which can be safely skipping on cifs (I hope). If a different dentry is returned, the first one is put. If necessary the fact that it is new can be determined by comparing pointers. A new dentry will certainly have a new pointer (as the old is put after the new is obtained). Similarly if an error is returned (via ERR_PTR()) the original dentry is put. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-7-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-04fs: support getname_maybe_null() in move_mount()Christian Brauner
Allow move_mount() to work with NULL path arguments. Link: https://lore.kernel.org/r/20250221-brauner-open_tree-v1-8-dbcfcb98c676@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-01fs: place f_ref to 3rd cache line in struct file to resolve false sharingPan Deng
When running syscall pread in a high core count system, f_ref contends with the reading of f_mode, f_op, f_mapping, f_inode, f_flags in the same cache line. This change places f_ref to the 3rd cache line where fields are not updated as frequently as the 1st cache line, and the contention is grealy reduced according to tests. In addition, the size of file object is kept in 3 cache lines. This change has been tested with rocksdb benchmark readwhilewriting case in 1 socket 64 physical core 128 logical core baremetal machine, with build config CONFIG_RANDSTRUCT_NONE=y Command: ./db_bench --benchmarks="readwhilewriting" --threads $cnt --duration 60 The throughput(ops/s) is improved up to ~21%. ===== thread baseline compare 16 100% +1.3% 32 100% +2.2% 64 100% +7.2% 128 100% +20.9% It was also tested with UnixBench: syscall, fsbuffer, fstime, fsdisk cases that has been used for file struct layout tuning, no regression was observed. Signed-off-by: Pan Deng <pan.deng@intel.com> Link: https://lore.kernel.org/r/20250228020059.3023375-1-pan.deng@intel.com Tested-by: Lipeng Zhu <lipeng.zhu@intel.com> Reviewed-by: Tianyou Li <tianyou.li@intel.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27Change inode_operations.mkdir to return struct dentry *NeilBrown
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have complete control of sequencing on the actual filesystem (e.g. on a different server) and may find that the inode created for a mkdir request already exists in the icache and dcache by the time the mkdir request returns. For example, if the filesystem is mounted twice the directory could be visible on the other mount before it is on the original mount, and a pair of name_to_handle_at(), open_by_handle_at() calls could instantiate the directory inode with an IS_ROOT() dentry before the first mkdir returns. This means that the dentry passed to ->mkdir() may not be the one that is associated with the inode after the ->mkdir() completes. Some callers need to interact with the inode after the ->mkdir completes and they currently need to perform a lookup in the (rare) case that the dentry is no longer hashed. This lookup-after-mkdir requires that the directory remains locked to avoid races. Planned future patches to lock the dentry rather than the directory will mean that this lookup cannot be performed atomically with the mkdir. To remove this barrier, this patch changes ->mkdir to return the resulting dentry if it is different from the one passed in. Possible returns are: NULL - the directory was created and no other dentry was used ERR_PTR() - an error occurred non-NULL - this other dentry was spliced in This patch only changes file-systems to return "ERR_PTR(err)" instead of "err" or equivalent transformations. Subsequent patches will make further changes to some file-systems to return a correct dentry. Not all filesystems reliably result in a positive hashed dentry: - NFS, cifs, hostfs will sometimes need to perform a lookup of the name to get inode information. Races could result in this returning something different. Note that this lookup is non-atomic which is what we are trying to avoid. Placing the lookup in filesystem code means it only happens when the filesystem has no other option. - kernfs and tracefs leave the dentry negative and the ->revalidate operation ensures that lookup will be called to correctly populate the dentry. This could be fixed but I don't think it is important to any of the users of vfs_mkdir() which look at the dentry. The recommendation to use d_drop();d_splice_alias() is ugly but fits with current practice. A planned future patch will change this. Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21mm/filemap: fix miscalculated file range for filemap_fdatawrite_range_kick()Jingbo Xu
iocb->ki_pos has been updated with the number of written bytes since generic_perform_write(). Besides __filemap_fdatawrite_range() accepts the inclusive end of the data range. Fixes: 1d4457576570 ("mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue") Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Link: https://lore.kernel.org/r/20250218120209.88093-2-jefflexu@linux.alibaba.com Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21vfs: inline new_inode_pseudo() and de-staticize alloc_inode()Mateusz Guzik
The former is a no-op wrapper with the same argument. I left it in place to not lose the information who needs it -- one day "pseudo" inodes may start differing from what alloc_inode() returns. In the meantime no point taking a detour. Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20250212180459.1022983-1-mjguzik@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21vfs: inline getname()Mateusz Guzik
It is merely a trivial wrapper around getname_flags which adds a zeroed argument, no point paying for an extra call. Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20250206000105.432528-1-mjguzik@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21ioctl: Fix return type of several functions from long to intYuichiro Tsuji
Fix the return type of several functions from long to int to match its actu al behavior. These functions only return int values. This change improves type consistency across the filesystem code and aligns the function signatu re with its existing implementation and usage. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Yuichiro Tsuji <yuichtsu@amazon.com> Link: https://lore.kernel.org/r/20250121070844.4413-3-yuichtsu@amazon.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21open: Fix return type of several functions from long to intYuichiro Tsuji
Fix the return type of several functions from long to int to match its actu al behavior. These functions only return int values. This change improves type consistency across the filesystem code and aligns the function signatu re with its existing implementation and usage. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Yuichiro Tsuji <yuichtsu@amazon.com> Link: https://lore.kernel.org/r/20250121070844.4413-2-yuichtsu@amazon.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21vfs: use the new debug macros in inode_set_cached_link()Mateusz Guzik
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20250209185523.745956-4-mjguzik@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-21vfs: add initial support for CONFIG_DEBUG_VFSMateusz Guzik
Small collection of macros taken from mmdebug.h Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20250209185523.745956-2-mjguzik@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-20fuse: don't truncate cached, mutated symlinkMiklos Szeredi
Fuse allows the value of a symlink to change and this property is exploited by some filesystems (e.g. CVMFS). It has been observed, that sometimes after changing the symlink contents, the value is truncated to the old size. This is caused by fuse_getattr() racing with fuse_reverse_inval_inode(). fuse_reverse_inval_inode() updates the fuse_inode's attr_version, which results in fuse_change_attributes() exiting before updating the cached attributes This is okay, as the cached attributes remain invalid and the next call to fuse_change_attributes() will likely update the inode with the correct values. The reason this causes problems is that cached symlinks will be returned through page_get_link(), which truncates the symlink to inode->i_size. This is correct for filesystems that don't mutate symlinks, but in this case it causes bad behavior. The solution is to just remove this truncation. This can cause a regression in a filesystem that relies on supplying a symlink larger than the file size, but this is unlikely. If that happens we'd need to make this behavior conditional. Reported-by: Laura Promberger <laura.promberger@cern.ch> Tested-by: Sam Lewis <samclewis@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20250220100258.793363-1-mszeredi@redhat.com Reviewed-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-13ext4: introduce linear search for dentriesTheodore Ts'o
This patch addresses an issue where some files in case-insensitive directories become inaccessible due to changes in how the kernel function, utf8_casefold(), generates case-folded strings from the commit 5c26d2f1d3f5 ("unicode: Don't special case ignorable code points"). There are good reasons why this change should be made; it's actually quite stupid that Unicode seems to think that the characters ❤ and ❤️ should be casefolded. Unfortimately because of the backwards compatibility issue, this commit was reverted in 231825b2e1ff. This problem is addressed by instituting a brute-force linear fallback if a lookup fails on case-folded directory, which does result in a performance hit when looking up files affected by the changing how thekernel treats ignorable Uniode characters, or when attempting to look up non-existent file names. So this fallback can be disabled by setting an encoding flag if in the future, the system administrator or the manufacturer of a mobile handset or tablet can be sure that there was no opportunity for a kernel to insert file names with incompatible encodings. Fixes: 5c26d2f1d3f5 ("unicode: Don't special case ignorable code points") Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
2025-02-07vfs: sanity check the length passed to inode_set_cached_link()Mateusz Guzik
This costs a strlen() call when instatianating a symlink. Preferably it would be hidden behind VFS_WARN_ON (or compatible), but there is no such facility at the moment. With the facility in place the call can be patched out in production kernels. In the meantime, since the cost is being paid unconditionally, use the result to a fixup the bad caller. This is not expected to persist in the long run (tm). Sample splat: bad length passed for symlink [/tmp/syz-imagegen43743633/file0/file0] (got 131109, expected 37) [rest of WARN blurp goes here] Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20250204213207.337980-1-mjguzik@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-07fsnotify: use accessor to set FMODE_NONOTIFY_*Amir Goldstein
The FMODE_NONOTIFY_* bits are a 2-bits mode. Open coding manipulation of those bits is risky. Use an accessor file_set_fsnotify_mode() to set the mode. Rename file_set_fsnotify_mode() => file_set_fsnotify_mode_from_watchers() to make way for the simple accessor name. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20250203223205.861346-2-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-06vfs: remove some unused old mount api codeEric Sandeen
Remove reconfigure_single, mount_single, and compare_single now that no users remain. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Link: https://lore.kernel.org/r/20250205213931.74614-5-sandeen@redhat.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-01-26Merge tag 'mm-stable-2025-01-26-14-59' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "The various patchsets are summarized below. Plus of course many indivudual patches which are described in their changelogs. - "Allocate and free frozen pages" from Matthew Wilcox reorganizes the page allocator so we end up with the ability to allocate and free zero-refcount pages. So that callers (ie, slab) can avoid a refcount inc & dec - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use large folios other than PMD-sized ones - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and fixes for this small built-in kernel selftest - "mas_anode_descend() related cleanup" from Wei Yang tidies up part of the mapletree code - "mm: fix format issues and param types" from Keren Sun implements a few minor code cleanups - "simplify split calculation" from Wei Yang provides a few fixes and a test for the mapletree code - "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes continues the work of moving vma-related code into the (relatively) new mm/vma.c - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David Hildenbrand cleans up and rationalizes handling of gfp flags in the page allocator - "readahead: Reintroduce fix for improper RA window sizing" from Jan Kara is a second attempt at fixing a readahead window sizing issue. It should reduce the amount of unnecessary reading - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng addresses an issue where "huge" amounts of pte pagetables are accumulated: https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/ Qi's series addresses this windup by synchronously freeing PTE memory within the context of madvise(MADV_DONTNEED) - "selftest/mm: Remove warnings found by adding compiler flags" from Muhammad Usama Anjum fixes some build warnings in the selftests code when optional compiler warnings are enabled - "mm: don't use __GFP_HARDWALL when migrating remote pages" from David Hildenbrand tightens the allocator's observance of __GFP_HARDWALL - "pkeys kselftests improvements" from Kevin Brodsky implements various fixes and cleanups in the MM selftests code, mainly pertaining to the pkeys tests - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to estimate application working set size - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn provides some cleanups to memcg's hugetlb charging logic - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song removes the global swap cgroup lock. A speedup of 10% for a tmpfs-based kernel build was demonstrated - "zram: split page type read/write handling" from Sergey Senozhatsky has several fixes and cleaups for zram in the area of zram_write_page(). A watchdog softlockup warning was eliminated - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky cleans up the pagetable destructor implementations. A rare use-after-free race is fixed - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes simplifies and cleans up the debugging code in the VMA merging logic - "Account page tables at all levels" from Kevin Brodsky cleans up and regularizes the pagetable ctor/dtor handling. This results in improvements in accounting accuracy - "mm/damon: replace most damon_callback usages in sysfs with new core functions" from SeongJae Park cleans up and generalizes DAMON's sysfs file interface logic - "mm/damon: enable page level properties based monitoring" from SeongJae Park increases the amount of information which is presented in response to DAMOS actions - "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes DAMON's long-deprecated debugfs interfaces. Thus the migration to sysfs is completed - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter Xu cleans up and generalizes the hugetlb reservation accounting - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino removes a never-used feature of the alloc_pages_bulk() interface - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park extends DAMOS filters to support not only exclusion (rejecting), but also inclusion (allowing) behavior - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi introduces a new memory descriptor for zswap.zpool that currently overlaps with struct page for now. This is part of the effort to reduce the size of struct page and to enable dynamic allocation of memory descriptors - "mm, swap: rework of swap allocator locks" from Kairui Song redoes and simplifies the swap allocator locking. A speedup of 400% was demonstrated for one workload. As was a 35% reduction for kernel build time with swap-on-zram - "mm: update mips to use do_mmap(), make mmap_region() internal" from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that mmap_region() can be made MM-internal - "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU regressions and otherwise improves MGLRU performance - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park updates DAMON documentation - "Cleanup for memfd_create()" from Isaac Manjarres does that thing - "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand provides various cleanups in the areas of hugetlb folios, THP folios and migration - "Uncached buffered IO" from Jens Axboe implements the new RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache reading and writing. To permite userspace to address issues with massive buildup of useless pagecache when reading/writing fast devices - "selftests/mm: virtual_address_range: Reduce memory" from Thomas Weißschuh fixes and optimizes some of the MM selftests" * tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm/compaction: fix UBSAN shift-out-of-bounds warning s390/mm: add missing ctor/dtor on page table upgrade kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags() tools: add VM_WARN_ON_VMG definition mm/damon/core: use str_high_low() helper in damos_wmark_wait_us() seqlock: add missing parameter documentation for raw_seqcount_try_begin() mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh mm/page_alloc: remove the incorrect and misleading comment zram: remove zcomp_stream_put() from write_incompressible_page() mm: separate move/undo parts from migrate_pages_batch() mm/kfence: use str_write_read() helper in get_access_type() selftests/mm/mkdirty: fix memory leak in test_uffdio_copy() kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags() selftests/mm: virtual_address_range: avoid reading from VM_IO mappings selftests/mm: vm_util: split up /proc/self/smaps parsing selftests/mm: virtual_address_range: unmap chunks after validation selftests/mm: virtual_address_range: mmap() without PROT_WRITE selftests/memfd/memfd_test: fix possible NULL pointer dereference mm: add FGP_DONTCACHE folio creation flag mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue ...
2025-01-25mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issueJens Axboe
When a buffered write submitted with IOCB_DONTCACHE has been successfully submitted, call filemap_fdatawrite_range_kick() to kick off the IO. File systems call generic_write_sync() for any successful buffered write submission, hence add the logic here rather than needing to modify the file system. Link: https://lkml.kernel.org/r/20241220154831.1086649-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Brian Foster <bfoster@redhat.com> Cc: Chris Mason <clm@meta.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-25mm/filemap: add filemap_fdatawrite_range_kick() helperJens Axboe
Works like filemap_fdatawrite_range(), except it's a non-integrity data writeback and hence only starts writeback on the specified range. Will help facilitate generically starting uncached writeback from generic_write_sync(), as header dependencies preclude doing this inline from fs.h. Link: https://lkml.kernel.org/r/20241220154831.1086649-11-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Brian Foster <bfoster@redhat.com> Cc: Chris Mason <clm@meta.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-25fs: add RWF_DONTCACHE iocb and FOP_DONTCACHE file_operations flagJens Axboe
If a file system supports uncached buffered IO, it may set FOP_DONTCACHE and enable support for RWF_DONTCACHE. If RWF_DONTCACHE is attempted without the file system supporting it, it'll get errored with -EOPNOTSUPP. Link: https://lkml.kernel.org/r/20241220154831.1086649-8-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Brian Foster <bfoster@redhat.com> Cc: Chris Mason <clm@meta.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>