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2023-10-30Merge tag 'vfs-6.7.ctime' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs Pull vfs inode time accessor updates from Christian Brauner: "This finishes the conversion of all inode time fields to accessor functions as discussed on list. Changing timestamps manually as we used to do before is error prone. Using accessors function makes this robust. It does not contain the switch of the time fields to discrete 64 bit integers to replace struct timespec and free up space in struct inode. But after this, the switch can be trivially made and the patch should only affect the vfs if we decide to do it" * tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits) fs: rename inode i_atime and i_mtime fields security: convert to new timestamp accessors selinux: convert to new timestamp accessors apparmor: convert to new timestamp accessors sunrpc: convert to new timestamp accessors mm: convert to new timestamp accessors bpf: convert to new timestamp accessors ipc: convert to new timestamp accessors linux: convert to new timestamp accessors zonefs: convert to new timestamp accessors xfs: convert to new timestamp accessors vboxsf: convert to new timestamp accessors ufs: convert to new timestamp accessors udf: convert to new timestamp accessors ubifs: convert to new timestamp accessors tracefs: convert to new timestamp accessors sysv: convert to new timestamp accessors squashfs: convert to new timestamp accessors server: convert to new timestamp accessors client: convert to new timestamp accessors ...
2023-10-30Merge tag 'vfs-6.7.xattr' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs Pull vfs xattr updates from Christian Brauner: "The 's_xattr' field of 'struct super_block' currently requires a mutable table of 'struct xattr_handler' entries (although each handler itself is const). However, no code in vfs actually modifies the tables. This changes the type of 's_xattr' to allow const tables, and modifies existing file systems to move their tables to .rodata. This is desirable because these tables contain entries with function pointers in them; moving them to .rodata makes it considerably less likely to be modified accidentally or maliciously at runtime" * tag 'vfs-6.7.xattr' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (30 commits) const_structs.checkpatch: add xattr_handler net: move sockfs_xattr_handlers to .rodata shmem: move shmem_xattr_handlers to .rodata overlayfs: move xattr tables to .rodata xfs: move xfs_xattr_handlers to .rodata ubifs: move ubifs_xattr_handlers to .rodata squashfs: move squashfs_xattr_handlers to .rodata smb: move cifs_xattr_handlers to .rodata reiserfs: move reiserfs_xattr_handlers to .rodata orangefs: move orangefs_xattr_handlers to .rodata ocfs2: move ocfs2_xattr_handlers and ocfs2_xattr_handler_map to .rodata ntfs3: move ntfs_xattr_handlers to .rodata nfs: move nfs4_xattr_handlers to .rodata kernfs: move kernfs_xattr_handlers to .rodata jfs: move jfs_xattr_handlers to .rodata jffs2: move jffs2_xattr_handlers to .rodata hfsplus: move hfsplus_xattr_handlers to .rodata hfs: move hfs_xattr_handlers to .rodata gfs2: move gfs2_xattr_handlers_max to .rodata fuse: move fuse_xattr_handlers to .rodata ...
2023-10-18mm: convert to new timestamp accessorsJeff Layton
Convert to using the new inode timestamp accessor functions. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/20231004185347.80880-80-jlayton@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-10shmem: move shmem_xattr_handlers to .rodataWedson Almeida Filho
This makes it harder for accidental or malicious changes to shmem_xattr_handlers at runtime. Cc: Hugh Dickins <hughd@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20230930050033.41174-29-wedsonaf@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-09-20Revert "tmpfs: add support for multigrain timestamps"Christian Brauner
This reverts commit d48c3397291690c3576d6c983b0a86ecbc203cac. Users reported regressions due to enabling multi-grained timestamps unconditionally. As no clear consensus on a solution has come up and the discussion has gone back to the drawing board revert the infrastructure changes for. If it isn't code that's here to stay, make it go away. Message-ID: <20230920-keine-eile-c9755b5825db@brauner> Acked-by: Jan Kara <jack@suse.cz> Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-29Merge tag 'mm-stable-2023-08-28-18-26' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list") - Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which reduces the special-case code for handling hugetlb pages in GUP. It also speeds up GUP handling of transparent hugepages. - Peng Zhang provides some maple tree speedups ("Optimize the fast path of mas_store()"). - Sergey Senozhatsky has improved te performance of zsmalloc during compaction (zsmalloc: small compaction improvements"). - Domenico Cerasuolo has developed additional selftest code for zswap ("selftests: cgroup: add zswap test program"). - xu xin has doe some work on KSM's handling of zero pages. These changes are mainly to enable the user to better understand the effectiveness of KSM's treatment of zero pages ("ksm: support tracking KSM-placed zero-pages"). - Jeff Xu has fixes the behaviour of memfd's MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED"). - David Howells has fixed an fscache optimization ("mm, netfs, fscache: Stop read optimisation when folio removed from pagecache"). - Axel Rasmussen has given userfaultfd the ability to simulate memory poisoning ("add UFFDIO_POISON to simulate memory poisoning with UFFD"). - Miaohe Lin has contributed some routine maintenance work on the memory-failure code ("mm: memory-failure: remove unneeded PageHuge() check"). - Peng Zhang has contributed some maintenance work on the maple tree code ("Improve the validation for maple tree and some cleanup"). - Hugh Dickins has optimized the collapsing of shmem or file pages into THPs ("mm: free retracted page table by RCU"). - Jiaqi Yan has a patch series which permits us to use the healthy subpages within a hardware poisoned huge page for general purposes ("Improve hugetlbfs read on HWPOISON hugepages"). - Kemeng Shi has done some maintenance work on the pagetable-check code ("Remove unused parameters in page_table_check"). - More folioification work from Matthew Wilcox ("More filesystem folio conversions for 6.6"), ("Followup folio conversions for zswap"). And from ZhangPeng ("Convert several functions in page_io.c to use a folio"). - page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext"). - Baoquan He has converted some architectures to use the GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert architectures to take GENERIC_IOREMAP way"). - Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support batched/deferred tlb shootdown during page reclamation/migration"). - Better maple tree lockdep checking from Liam Howlett ("More strict maple tree lockdep"). Liam also developed some efficiency improvements ("Reduce preallocations for maple tree"). - Cleanup and optimization to the secondary IOMMU TLB invalidation, from Alistair Popple ("Invalidate secondary IOMMU TLB on permission upgrade"). - Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes for arm64"). - Kemeng Shi provides some maintenance work on the compaction code ("Two minor cleanups for compaction"). - Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle most file-backed faults under the VMA lock"). - Aneesh Kumar contributes code to use the vmemmap optimization for DAX on ppc64, under some circumstances ("Add support for DAX vmemmap optimization for ppc64"). - page-ext cleanups from Kemeng Shi ("add page_ext_data to get client data in page_ext"), ("minor cleanups to page_ext header"). - Some zswap cleanups from Johannes Weiner ("mm: zswap: three cleanups"). - kmsan cleanups from ZhangPeng ("minor cleanups for kmsan"). - VMA handling cleanups from Kefeng Wang ("mm: convert to vma_is_initial_heap/stack()"). - DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes: implement DAMOS tried total bytes file"), ("Extend DAMOS filters for address ranges and DAMON monitoring targets"). - Compaction work from Kemeng Shi ("Fixes and cleanups to compaction"). - Liam Howlett has improved the maple tree node replacement code ("maple_tree: Change replacement strategy"). - ZhangPeng has a general code cleanup - use the K() macro more widely ("cleanup with helper macro K()"). - Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for memmap on memory feature on ppc64"). - pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list in page_alloc"), ("Two minor cleanups for get pageblock migratetype"). - Vishal Moola introduces a memory descriptor for page table tracking, "struct ptdesc" ("Split ptdesc from struct page"). - memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups for vm.memfd_noexec"). - MM include file rationalization from Hugh Dickins ("arch: include asm/cacheflush.h in asm/hugetlb.h"). - THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text output"). - kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use object_cache instead of kmemleak_initialized"). - More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor and _folio_order"). - A VMA locking scalability improvement from Suren Baghdasaryan ("Per-VMA lock support for swap and userfaults"). - pagetable handling cleanups from Matthew Wilcox ("New page table range API"). - A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop using page->private on tail pages for THP_SWAP + cleanups"). - Cleanups and speedups to the hugetlb fault handling from Matthew Wilcox ("Change calling convention for ->huge_fault"). - Matthew Wilcox has also done some maintenance work on the MM subsystem documentation ("Improve mm documentation"). * tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (489 commits) maple_tree: shrink struct maple_tree maple_tree: clean up mas_wr_append() secretmem: convert page_is_secretmem() to folio_is_secretmem() nios2: fix flush_dcache_page() for usage from irq context hugetlb: add documentation for vma_kernel_pagesize() mm: add orphaned kernel-doc to the rst files. mm: fix clean_record_shared_mapping_range kernel-doc mm: fix get_mctgt_type() kernel-doc mm: fix kernel-doc warning from tlb_flush_rmaps() mm: remove enum page_entry_size mm: allow ->huge_fault() to be called without the mmap_lock held mm: move PMD_ORDER to pgtable.h mm: remove checks for pte_index memcg: remove duplication detection for mem_cgroup_uncharge_swap mm/huge_memory: work on folio->swap instead of page->private when splitting folio mm/swap: inline folio_set_swap_entry() and folio_swap_entry() mm/swap: use dedicated entry for swap in folio mm/swap: stop using page->private on tail pages for THP_SWAP selftests/mm: fix WARNING comparing pointer to 0 selftests: cgroup: fix test_kmem_memcg_deletion kernel mem check ...
2023-08-28Merge tag 'v6.6-vfs.tmpfs' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull libfs and tmpfs updates from Christian Brauner: "This cycle saw a lot of work for tmpfs that required changes to the vfs layer. Andrew, Hugh, and I decided to take tmpfs through vfs this cycle. Things will go back to mm next cycle. Features ======== - By far the biggest work is the quota support for tmpfs. New tmpfs quota infrastructure is added to support it and a new QFMT_SHMEM uapi option is exposed. This offers user and group quotas to tmpfs (project quotas will be added later). Similar to other filesystems tmpfs quota are not supported within user namespaces yet. - Add support for user xattrs. While tmpfs already supports security xattrs (security.*) and POSIX ACLs for a long time it lacked support for user xattrs (user.*). With this pull request tmpfs will be able to support a limited number of user xattrs. This is accompanied by a fix (see below) to limit persistent simple xattr allocations. - Add support for stable directory offsets. Currently tmpfs relies on the libfs provided cursor-based mechanism for readdir. This causes issues when a tmpfs filesystem is exported via NFS. NFS clients do not open directories. Instead, each server-side readdir operation opens the directory, reads it, and then closes it. Since the cursor state for that directory is associated with the opened file it is discarded after each readdir operation. Such directory offsets are not just cached by NFS clients but also various userspace libraries based on these clients. As it stands there is no way to invalidate the caches when directory offsets have changed and the whole application depends on unchanging directory offsets. At LSFMM we discussed how to solve this problem and decided to support stable directory offsets. libfs now allows filesystems like tmpfs to use an xarrary to map a directory offset to a dentry. This mechanism is currently only used by tmpfs but can be supported by others as well. Fixes ===== - Change persistent simple xattrs allocations in libfs from GFP_KERNEL to GPF_KERNEL_ACCOUNT so they're subject to memory cgroup limits. Since this is a change to libfs it affects both tmpfs and kernfs. - Correctly verify {g,u}id mount options. A new filesystem context is created via fsopen() which records the namespace that becomes the owning namespace of the superblock when fsconfig(FSCONFIG_CMD_CREATE) is called for filesystems that are mountable in namespaces. However, fsconfig() calls can occur in a namespace different from the namespace where fsopen() has been called. Currently, when fsconfig() is called to set {g,u}id mount options the requested {g,u}id is mapped into a k{g,u}id according to the namespace where fsconfig() was called from. The resulting k{g,u}id is not guaranteed to be resolvable in the namespace of the filesystem (the one that fsopen() was called in). This means it's possible for an unprivileged user to create files owned by any group in a tmpfs mount since it's possible to set the setid bits on the tmpfs directory. The contract for {g,u}id mount options and {g,u}id values in general set from userspace has always been that they are translated according to the caller's idmapping. In so far, tmpfs has been doing the correct thing. But since tmpfs is mountable in unprivileged contexts it is also necessary to verify that the resulting {k,g}uid is representable in the namespace of the superblock to avoid such bugs. The new mount api's cross-namespace delegation abilities are already widely used. Having talked to a bunch of userspace this is the most faithful solution with minimal regression risks" * tag 'v6.6-vfs.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: tmpfs,xattr: GFP_KERNEL_ACCOUNT for simple xattrs mm: invalidation check mapping before folio_contains tmpfs: trivial support for direct IO tmpfs,xattr: enable limited user extended attributes tmpfs: track free_ispace instead of free_inodes xattr: simple_xattr_set() return old_xattr to be freed tmpfs: verify {g,u}id mount options correctly shmem: move spinlock into shmem_recalc_inode() to fix quota support libfs: Remove parent dentry locking in offset_iterate_dir() libfs: Add a lock class for the offset map's xa_lock shmem: stable directory offsets shmem: Refactor shmem_symlink() libfs: Add directory operations for stable offsets shmem: fix quota lock nesting in huge hole handling shmem: Add default quota limit mount options shmem: quota support shmem: prepare shmem quota infrastructure quota: Check presence of quota operation structures instead of ->quota_read and ->quota_write callbacks shmem: make shmem_get_inode() return ERR_PTR instead of NULL shmem: make shmem_inode_acct_block() return error
2023-08-28Merge tag 'v6.6-vfs.ctime' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs timestamp updates from Christian Brauner: "This adds VFS support for multi-grain timestamps and converts tmpfs, xfs, ext4, and btrfs to use them. This carries acks from all relevant filesystems. The VFS always uses coarse-grained timestamps when updating the ctime and mtime after a change. This has the benefit of allowing filesystems to optimize away a lot of metadata updates, down to around 1 per jiffy, even when a file is under heavy writes. Unfortunately, this has always been an issue when we're exporting via NFSv3, which relies on timestamps to validate caches. A lot of changes can happen in a jiffy, so timestamps aren't sufficient to help the client decide to invalidate the cache. Even with NFSv4, a lot of exported filesystems don't properly support a change attribute and are subject to the same problems with timestamp granularity. Other applications have similar issues with timestamps (e.g., backup applications). If we were to always use fine-grained timestamps, that would improve the situation, but that becomes rather expensive, as the underlying filesystem would have to log a lot more metadata updates. This introduces fine-grained timestamps that are used when they are actively queried. This uses the 31st bit of the ctime tv_nsec field to indicate that something has queried the inode for the mtime or ctime. When this flag is set, on the next mtime or ctime update, the kernel will fetch a fine-grained timestamp instead of the usual coarse-grained one. As POSIX generally mandates that when the mtime changes, the ctime must also change the kernel always stores normalized ctime values, so only the first 30 bits of the tv_nsec field are ever used. Filesytems can opt into this behavior by setting the FS_MGTIME flag in the fstype. Filesystems that don't set this flag will continue to use coarse-grained timestamps. Various preparatory changes, fixes and cleanups are included: - Fixup all relevant places where POSIX requires updating ctime together with mtime. This is a wide-range of places and all maintainers provided necessary Acks. - Add new accessors for inode->i_ctime directly and change all callers to rely on them. Plain accesses to inode->i_ctime are now gone and it is accordingly rename to inode->__i_ctime and commented as requiring accessors. - Extend generic_fillattr() to pass in a request mask mirroring in a sense the statx() uapi. This allows callers to pass in a request mask to only get a subset of attributes filled in. - Rework timestamp updates so it's possible to drop the @now parameter the update_time() inode operation and associated helpers. - Add inode_update_timestamps() and convert all filesystems to it removing a bunch of open-coding" * tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (107 commits) btrfs: convert to multigrain timestamps ext4: switch to multigrain timestamps xfs: switch to multigrain timestamps tmpfs: add support for multigrain timestamps fs: add infrastructure for multigrain timestamps fs: drop the timespec64 argument from update_time xfs: have xfs_vn_update_time gets its own timestamp fat: make fat_update_time get its own timestamp fat: remove i_version handling from fat_update_time ubifs: have ubifs_update_time use inode_update_timestamps btrfs: have it use inode_update_timestamps fs: drop the timespec64 arg from generic_update_time fs: pass the request_mask to generic_fillattr fs: remove silly warning from current_time gfs2: fix timestamp handling on quota inodes fs: rename i_ctime field to __i_ctime selinux: convert to ctime accessor functions security: convert to ctime accessor functions apparmor: convert to ctime accessor functions sunrpc: convert to ctime accessor functions ...
2023-08-24mm/swap: inline folio_set_swap_entry() and folio_swap_entry()David Hildenbrand
Let's simply work on the folio directly and remove the helpers. Link: https://lkml.kernel.org/r/20230821160849.531668-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Chris Li <chrisl@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-24merge mm-hotfixes-stable into mm-stable to pick up depended-upon changesAndrew Morton
2023-08-24shmem: fix smaps BUG sleeping while atomicHugh Dickins
smaps_pte_hole_lookup() is calling shmem_partial_swap_usage() with page table lock held: but shmem_partial_swap_usage() does cond_resched_rcu() if need_resched(): "BUG: sleeping function called from invalid context". Since shmem_partial_swap_usage() is designed to count across a range, but smaps_pte_hole_lookup() only calls it for a single page slot, just break out of the loop on the last or only page, before checking need_resched(). Link: https://lkml.kernel.org/r/6fe3b3ec-abdf-332f-5c23-6a3b3a3b11a9@google.com Fixes: 230100321518 ("mm/smaps: simplify shmem handling of pte holes") Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> [5.16+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-22tmpfs,xattr: GFP_KERNEL_ACCOUNT for simple xattrsHugh Dickins
It is particularly important for the userns mount case (when a sensible nr_inodes maximum may not be enforced) that tmpfs user xattrs be subject to memory cgroup limiting. Leave temporary buffer allocations as is, but change the persistent simple xattr allocations from GFP_KERNEL to GFP_KERNEL_ACCOUNT. This limits kernfs's cgroupfs too, but that's good. (I had intended to send this change earlier, but had been confused by shmem_alloc_inode() using GFP_KERNEL, and thought a discussion would be needed to change that too: no, I was forgetting the SLAB_ACCOUNT on that kmem_cache, which implicitly adds __GFP_ACCOUNT to all its allocations.) Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <f6953e5a-4183-8314-38f2-40be60998615@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-21mm/shmem.c: use helper macro K()ZhangPeng
Use helper macro K() to improve code readability. No functional modification involved. Link: https://lkml.kernel.org/r/20230804012559.2617515-5-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Nanyong Sun <sunnanyong@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-18mm: make PTE_MARKER_SWAPIN_ERROR more generalAxel Rasmussen
Patch series "add UFFDIO_POISON to simulate memory poisoning with UFFD", v4. This series adds a new userfaultfd feature, UFFDIO_POISON. See commit 4 for a detailed description of the feature. This patch (of 8): Future patches will reuse PTE_MARKER_SWAPIN_ERROR to implement UFFDIO_POISON, so make some various preparations for that: First, rename it to just PTE_MARKER_POISONED. The "SWAPIN" can be confusing since we're going to re-use it for something not really related to swap. This can be particularly confusing for things like hugetlbfs, which doesn't support swap whatsoever. Also rename some various helper functions. Next, fix pte marker copying for hugetlbfs. Previously, it would WARN on seeing a PTE_MARKER_SWAPIN_ERROR, since hugetlbfs doesn't support swap. But, since we're going to re-use it, we want it to go ahead and copy it just like non-hugetlbfs memory does today. Since the code to do this is more complicated now, pull it out into a helper which can be re-used in both places. While we're at it, also make it slightly more explicit in its handling of e.g. uffd wp markers. For non-hugetlbfs page faults, instead of returning VM_FAULT_SIGBUS for an error entry, return VM_FAULT_HWPOISON. For most cases this change doesn't matter, e.g. a userspace program would receive a SIGBUS either way. But for UFFDIO_POISON, this change will let KVM guests get an MCE out of the box, instead of giving a SIGBUS to the hypervisor and requiring it to somehow inject an MCE. Finally, for hugetlbfs faults, handle PTE_MARKER_POISONED, and return VM_FAULT_HWPOISON_LARGE in such cases. Note that this can't happen today because the lack of swap support means we'll never end up with such a PTE anyway, but this behavior will be needed once such entries *can* show up via UFFDIO_POISON. Link: https://lkml.kernel.org/r/20230707215540.2324998-1-axelrasmussen@google.com Link: https://lkml.kernel.org/r/20230707215540.2324998-2-axelrasmussen@google.com Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Brian Geffon <bgeffon@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Gaosheng Cui <cuigaosheng1@huawei.com> Cc: Huang, Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: James Houghton <jthoughton@google.com> Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nadav Amit <namit@vmware.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: T.J. Alumbaugh <talumbau@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-18mm: increase usage of folio_next_index() helperSidhartha Kumar
Simplify code pattern of 'folio->index + folio_nr_pages(folio)' by using the existing helper folio_next_index(). Link: https://lkml.kernel.org/r/20230627174349.491803-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Suggested-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-11tmpfs: trivial support for direct IOHugh Dickins
Depending upon your philosophical viewpoint, either tmpfs always does direct IO, or it cannot ever do direct IO; but whichever, if tmpfs is to stand in for a more sophisticated filesystem, it can be helpful for tmpfs to support O_DIRECT. So, give tmpfs a shmem_file_open() method, to set the FMODE_CAN_ODIRECT flag: then unchanged shmem_file_read_iter() and new shmem_file_write_iter() do the work (without any shmem_direct_IO() stub). Perhaps later, once the direct_IO method has been eliminated from all filesystems, generic_file_write_iter() will be such that tmpfs can again use it, even for O_DIRECT. xfstests auto generic which were not run on tmpfs before but now pass: 036 091 113 125 130 133 135 198 207 208 209 210 211 212 214 226 239 263 323 355 391 406 412 422 427 446 451 465 551 586 591 609 615 647 708 729 with no new failures. LTP dio tests which were not run on tmpfs before but now pass: dio01 through dio30, except for dio04 and dio10, which fail because tmpfs dio read and write allow odd count: tmpfs could be made stricter, but would that be an improvement? Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <6f2742-6f1f-cae9-7c5b-ed20fc53215@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-11tmpfs: add support for multigrain timestampsJeff Layton
Enable multigrain timestamps, which should ensure that there is an apparent change to the timestamp whenever it has been written after being actively observed via getattr. tmpfs only requires the FS_MGTIME flag. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@kernel.org> Message-Id: <20230807-mgctime-v7-10-d1dec143a704@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-10tmpfs,xattr: enable limited user extended attributesHugh Dickins
Enable "user." extended attributes on tmpfs, limiting them by tracking the space they occupy, and deducting that space from the limited ispace (unless tmpfs mounted with nr_inodes=0 to leave that ispace unlimited). tmpfs inodes and simple xattrs are both unswappable, and have to be in lowmem on a 32-bit highmem kernel: so the ispace limit is appropriate for xattrs, without any need for a further mount option. Add simple_xattr_space() to give approximate but deterministic estimate of the space taken up by each xattr: with simple_xattrs_free() outputting the space freed if required (but kernfs and even some tmpfs usages do not require that, so don't waste time on strlen'ing if not needed). Security and trusted xattrs were already supported: for consistency and simplicity, account them from the same pool; though there's a small risk that a tmpfs with enough space before would now be considered too small. When extended attributes are used, "df -i" does show more IUsed and less IFree than can be explained by the inodes: document that (manpage later). xfstests tests/generic which were not run on tmpfs before but now pass: 020 037 062 070 077 097 103 117 337 377 454 486 523 533 611 618 728 with no new failures. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Message-Id: <2e63b26e-df46-5baa-c7d6-f9a8dd3282c5@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09tmpfs: track free_ispace instead of free_inodesHugh Dickins
In preparation for assigning some inode space to extended attributes, keep track of free_ispace instead of number of free_inodes: as if one tmpfs inode (and accompanying dentry) occupies very approximately 1KiB. Unsigned long is large enough for free_ispace, on 64-bit and on 32-bit: but take care to enforce the maximum. And fix the nr_blocks maximum on 32-bit: S64_MAX would be too big for it there, so say LONG_MAX instead. Delete the incorrect limited<->unlimited blocks/inodes comment above shmem_reconfigure(): leave it to the error messages below to describe. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Message-Id: <4fe1739-d9e7-8dfd-5bce-12e7339711da@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09xattr: simple_xattr_set() return old_xattr to be freedHugh Dickins
tmpfs wants to support limited user extended attributes, but kernfs (or cgroupfs, the only kernfs with KERNFS_ROOT_SUPPORT_USER_XATTR) already supports user extended attributes through simple xattrs: but limited by a policy (128KiB per inode) too liberal to be used on tmpfs. To allow a different limiting policy for tmpfs, without affecting the policy for kernfs, change simple_xattr_set() to return the replaced or removed xattr (if any), leaving the caller to update their accounting then free the xattr (by simple_xattr_free(), renamed from the static free_simple_xattr()). Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Message-Id: <158c6585-2aa7-d4aa-90ff-f7c3f8fe407c@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09tmpfs: verify {g,u}id mount options correctlyChristian Brauner
A while ago we received the following report: "The other outstanding issue I noticed comes from the fact that fsconfig syscalls may occur in a different userns than that which called fsopen. That means that resolving the uid/gid via current_user_ns() can save a kuid that isn't mapped in the associated namespace when the filesystem is finally mounted. This means that it is possible for an unprivileged user to create files owned by any group in a tmpfs mount (since we can set the SUID bit on the tmpfs directory), or a tmpfs that is owned by any user, including the root group/user." The contract for {g,u}id mount options and {g,u}id values in general set from userspace has always been that they are translated according to the caller's idmapping. In so far, tmpfs has been doing the correct thing. But since tmpfs is mountable in unprivileged contexts it is also necessary to verify that the resulting {k,g}uid is representable in the namespace of the superblock to avoid such bugs as above. The new mount api's cross-namespace delegation abilities are already widely used. After having talked to a bunch of userspace this is the most faithful solution with minimal regression risks. I know of one users - systemd - that makes use of the new mount api in this way and they don't set unresolable {g,u}ids. So the regression risk is minimal. Link: https://lore.kernel.org/lkml/CALxfFW4BXhEwxR0Q5LSkg-8Vb4r2MONKCcUCVioehXQKr35eHg@mail.gmail.com Fixes: f32356261d44 ("vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API") Reviewed-by: "Seth Forshee (DigitalOcean)" <sforshee@kernel.org> Reported-by: Seth Jenkins <sethjenkins@google.com> Message-Id: <20230801-vfs-fs_context-uidgid-v1-1-daf46a050bbf@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: move spinlock into shmem_recalc_inode() to fix quota supportHugh Dickins
Commit "shmem: fix quota lock nesting in huge hole handling" was not so good: Smatch caught shmem_recalc_inode()'s shmem_inode_unacct_blocks() descending into quota_send_warning(): where blocking GFP_NOFS is used, yet shmem_recalc_inode() is called holding the shmem inode's info->lock. Yes, both __dquot_alloc_space() and __dquot_free_space() are commented "This operation can block, but only after everything is updated" - when calling flush_warnings() at the end - both its print_warning() and its quota_send_warning() may block. Rework shmem_recalc_inode() to take the shmem inode's info->lock inside, and drop it before calling shmem_inode_unacct_blocks(). And why were the spin_locks disabling interrupts? That was just a relic from when shmem_charge() and shmem_uncharge() were called while holding i_pages xa_lock: stop disabling interrupts for info->lock now. To help stop me from making the same mistake again, add a might_sleep() into shmem_inode_acct_block() and shmem_inode_unacct_blocks(); and those functions have grown, so let the compiler decide whether to inline them. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/linux-fsdevel/ffd7ca34-7f2a-44ee-b05d-b54d920ce076@moroto.mountain/ Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <29f48045-2cb5-7db-ecf1-72462f1bef5@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: stable directory offsetsChuck Lever
The current cursor-based directory offset mechanism doesn't work when a tmpfs filesystem is exported via NFS. This is because NFS clients do not open directories. Each server-side READDIR operation has to open the directory, read it, then close it. The cursor state for that directory, being associated strictly with the opened struct file, is thus discarded after each NFS READDIR operation. Directory offsets are cached not only by NFS clients, but also by user space libraries on those clients. Essentially there is no way to invalidate those caches when directory offsets have changed on an NFS server after the offset-to-dentry mapping changes. Thus the whole application stack depends on unchanging directory offsets. The solution we've come up with is to make the directory offset for each file in a tmpfs filesystem stable for the life of the directory entry it represents. shmem_readdir() and shmem_dir_llseek() now use an xarray to map each directory offset (an loff_t integer) to the memory address of a struct dentry. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Message-Id: <168814734331.530310.3911190551060453102.stgit@manet.1015granger.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: Refactor shmem_symlink()Chuck Lever
De-duplicate the error handling paths. No change in behavior is expected. Suggested-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Message-Id: <168814733654.530310.9958360833543413152.stgit@manet.1015granger.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: fix quota lock nesting in huge hole handlingHugh Dickins
i_pages lock nests inside i_lock, but shmem_charge() and shmem_uncharge() were being called from THP splitting or collapsing while i_pages lock was held, and now go on to call dquot_alloc_block_nodirty() which takes i_lock to update i_blocks. We may well want to take i_lock out of this path later, in the non-quota case even if it's left in the quota case (or perhaps use i_lock instead of shmem's info->lock throughout); but don't get into that at this time. Move the shmem_charge() and shmem_uncharge() calls out from under i_pages lock, accounting the full batch of holes in a single call. Still pass the pages argument to shmem_uncharge(), but it happens now to be unused: shmem_recalc_inode() is designed to account for clean pages freed behind shmem's back, so it gets the accounting right by itself; then the later call to shmem_inode_unacct_blocks() led to imbalance (that WARN_ON(inode->i_blocks) in shmem_evict_inode()). Reported-by: syzbot+38ca19393fb3344f57e6@syzkaller.appspotmail.com Closes: https://lore.kernel.org/lkml/0000000000008e62f40600bfe080@google.com/ Reported-by: syzbot+440ff8cca06ee7a1d4db@syzkaller.appspotmail.com Closes: https://lore.kernel.org/lkml/00000000000076a7840600bfb6e8@google.com/ Signed-off-by: Hugh Dickins <hughd@google.com> Tested-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Message-Id: <20230725144510.253763-8-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: Add default quota limit mount optionsLukas Czerner
Allow system administrator to set default global quota limits at tmpfs mount time. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230725144510.253763-7-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: quota supportCarlos Maiolino
Now the basic infra-structure is in place, enable quota support for tmpfs. This offers user and group quotas to tmpfs (project quotas will be added later). Also, as other filesystems, the tmpfs quota is not supported within user namespaces yet, so idmapping is not translated. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230725144510.253763-6-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: make shmem_get_inode() return ERR_PTR instead of NULLCarlos Maiolino
Make shmem_get_inode() return ERR_PTR instead of NULL on error. This will be useful later when we introduce quota support. There should be no functional change. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230725144510.253763-3-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: make shmem_inode_acct_block() return errorLukas Czerner
Make shmem_inode_acct_block() return proper error code instead of bool. This will be useful later when we introduce quota support. There should be no functional change. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230725144510.253763-2-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09fs: pass the request_mask to generic_fillattrJeff Layton
generic_fillattr just fills in the entire stat struct indiscriminately today, copying data from the inode. There is at least one attribute (STATX_CHANGE_COOKIE) that can have side effects when it is reported, and we're looking at adding more with the addition of multigrain timestamps. Add a request_mask argument to generic_fillattr and have most callers just pass in the value that is passed to getattr. Have other callers (e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of STATX_CHANGE_COOKIE into generic_fillattr. Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@kernel.org> Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-27shmem: minor fixes to splice-read implementationHugh Dickins
HWPoison: my reading of folio_test_hwpoison() is that it only tests the head page of a large folio, whereas splice_folio_into_pipe() will splice as much of the folio as it can: so for safety we should also check the has_hwpoisoned flag, set if any of the folio's pages are hwpoisoned. (Perhaps that ugliness can be improved at the mm end later.) The call to splice_zeropage_into_pipe() risked overrunning past EOF: ask it for "part" not "len". Link: https://lkml.kernel.org/r/32c72c9c-72a8-115f-407d-f0148f368@google.com Fixes: bd194b187115 ("shmem: Implement splice-read") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: David Howells <dhowells@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-07-24shmem: convert to ctime accessor functionsJeff Layton
In later patches, we're going to change how the inode's ctime field is used. Switch to using accessor functions instead of raw accesses of inode->i_ctime. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230705190309.579783-85-jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-10shmem: convert to simple_rename_timestampJeff Layton
A rename potentially involves updating 4 different inode timestamps. Convert to the new simple_rename_timestamp helper function. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230705190309.579783-9-jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-28Merge tag 'mm-stable-2023-06-24-19-15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull mm updates from Andrew Morton: - Yosry Ahmed brought back some cgroup v1 stats in OOM logs - Yosry has also eliminated cgroup's atomic rstat flushing - Nhat Pham adds the new cachestat() syscall. It provides userspace with the ability to query pagecache status - a similar concept to mincore() but more powerful and with improved usability - Mel Gorman provides more optimizations for compaction, reducing the prevalence of page rescanning - Lorenzo Stoakes has done some maintanance work on the get_user_pages() interface - Liam Howlett continues with cleanups and maintenance work to the maple tree code. Peng Zhang also does some work on maple tree - Johannes Weiner has done some cleanup work on the compaction code - David Hildenbrand has contributed additional selftests for get_user_pages() - Thomas Gleixner has contributed some maintenance and optimization work for the vmalloc code - Baolin Wang has provided some compaction cleanups, - SeongJae Park continues maintenance work on the DAMON code - Huang Ying has done some maintenance on the swap code's usage of device refcounting - Christoph Hellwig has some cleanups for the filemap/directio code - Ryan Roberts provides two patch series which yield some rationalization of the kernel's access to pte entries - use the provided APIs rather than open-coding accesses - Lorenzo Stoakes has some fixes to the interaction between pagecache and directio access to file mappings - John Hubbard has a series of fixes to the MM selftesting code - ZhangPeng continues the folio conversion campaign - Hugh Dickins has been working on the pagetable handling code, mainly with a view to reducing the load on the mmap_lock - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from 128 to 8 - Domenico Cerasuolo has improved the zswap reclaim mechanism by reorganizing the LRU management - Matthew Wilcox provides some fixups to make gfs2 work better with the buffer_head code - Vishal Moola also has done some folio conversion work - Matthew Wilcox has removed the remnants of the pagevec code - their functionality is migrated over to struct folio_batch * tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits) mm/hugetlb: remove hugetlb_set_page_subpool() mm: nommu: correct the range of mmap_sem_read_lock in task_mem() hugetlb: revert use of page_cache_next_miss() Revert "page cache: fix page_cache_next/prev_miss off by one" mm/vmscan: fix root proactive reclaim unthrottling unbalanced node mm: memcg: rename and document global_reclaim() mm: kill [add|del]_page_to_lru_list() mm: compaction: convert to use a folio in isolate_migratepages_block() mm: zswap: fix double invalidate with exclusive loads mm: remove unnecessary pagevec includes mm: remove references to pagevec mm: rename invalidate_mapping_pagevec to mapping_try_invalidate mm: remove struct pagevec net: convert sunrpc from pagevec to folio_batch i915: convert i915_gpu_error to use a folio_batch pagevec: rename fbatch_count() mm: remove check_move_unevictable_pages() drm: convert drm_gem_put_pages() to use a folio_batch i915: convert shmem_sg_free_table() to use a folio_batch scatterlist: add sg_set_folio() ...
2023-06-19shmem: use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfsRoberto Sassu
As the ramfs-based tmpfs uses ramfs_init_fs_context() for the init_fs_context method, which allocates fc->s_fs_info, use ramfs_kill_sb() to free it and avoid a memory leak. Link: https://lkml.kernel.org/r/20230607161523.2876433-1-roberto.sassu@huaweicloud.com Fixes: c3b1b1cbf002 ("ramfs: add support for "mode=" mount option") Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Cc: Hugh Dickins <hughd@google.com> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-09mm: shmem: fix UAF bug in shmem_show_options()Tu Jinjiang
shmem_show_options() uses sbinfo->mpol without adding it's refcnt. This may lead to race with replacement of the mpol by remount. The execution sequence is as follows. CPU0 CPU1 shmem_show_options() shmem_reconfigure() shmem_show_mpol(seq, sbinfo->mpol) mpol = sbinfo->mpol mpol_put(mpol) mpol->mode The KASAN report is as follows. BUG: KASAN: slab-use-after-free in shmem_show_options+0x21b/0x340 Read of size 2 at addr ffff888124324004 by task mount/2388 CPU: 2 PID: 2388 Comm: mount Not tainted 6.4.0-rc3-00017-g9d646009f65d-dirty #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x37/0x50 print_report+0xd0/0x620 ? shmem_show_options+0x21b/0x340 ? __virt_addr_valid+0xf4/0x180 ? shmem_show_options+0x21b/0x340 kasan_report+0xb8/0xe0 ? shmem_show_options+0x21b/0x340 shmem_show_options+0x21b/0x340 ? __pfx_shmem_show_options+0x10/0x10 ? strchr+0x2c/0x50 ? strlen+0x23/0x40 ? seq_puts+0x7d/0x90 show_vfsmnt+0x1e6/0x260 ? __pfx_show_vfsmnt+0x10/0x10 ? __kasan_kmalloc+0x7f/0x90 seq_read_iter+0x57a/0x740 vfs_read+0x2e2/0x4a0 ? __pfx_vfs_read+0x10/0x10 ? down_write_killable+0xb8/0x140 ? __pfx_down_write_killable+0x10/0x10 ? __fget_light+0xa9/0x1e0 ? up_write+0x3f/0x80 ksys_read+0xb8/0x150 ? __pfx_ksys_read+0x10/0x10 ? fpregs_assert_state_consistent+0x55/0x60 ? exit_to_user_mode_prepare+0x2d/0x120 do_syscall_64+0x3c/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc </TASK> Allocated by task 2387: kasan_save_stack+0x22/0x50 kasan_set_track+0x25/0x30 __kasan_slab_alloc+0x59/0x70 kmem_cache_alloc+0xdd/0x220 mpol_new+0x83/0x150 mpol_parse_str+0x280/0x4a0 shmem_parse_one+0x364/0x520 vfs_parse_fs_param+0xf8/0x1a0 vfs_parse_fs_string+0xc9/0x130 shmem_parse_options+0xb2/0x110 path_mount+0x597/0xdf0 do_mount+0xcd/0xf0 __x64_sys_mount+0xbd/0x100 do_syscall_64+0x3c/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc Freed by task 2389: kasan_save_stack+0x22/0x50 kasan_set_track+0x25/0x30 kasan_save_free_info+0x2e/0x50 __kasan_slab_free+0x10e/0x1a0 kmem_cache_free+0x9c/0x350 shmem_reconfigure+0x278/0x370 reconfigure_super+0x383/0x450 path_mount+0xcc5/0xdf0 do_mount+0xcd/0xf0 __x64_sys_mount+0xbd/0x100 do_syscall_64+0x3c/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc The buggy address belongs to the object at ffff888124324000 which belongs to the cache numa_policy of size 32 The buggy address is located 4 bytes inside of freed 32-byte region [ffff888124324000, ffff888124324020) ================================================================== To fix the bug, shmem_get_sbmpol() / mpol_put() needs to be called before / after shmem_show_mpol() call. Link: https://lkml.kernel.org/r/20230525031640.593733-1-tujinjiang@huawei.com Signed-off-by: Tu Jinjiang <tujinjiang@huawei.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Nanyong Sun <sunnanyong@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-05-24shmem: Implement splice-readDavid Howells
The new filemap_splice_read() has an implicit expectation via filemap_get_pages() that ->read_folio() exists if ->readahead() doesn't fully populate the pagecache of the file it is reading from[1], potentially leading to a jump to NULL if this doesn't exist. shmem, however, (and by extension, tmpfs, ramfs and rootfs), doesn't have ->read_folio(), Work around this by equipping shmem with its own splice-read implementation, based on filemap_splice_read(), but able to paste in zero_page when there's a page missing. Signed-off-by: David Howells <dhowells@redhat.com> cc: Daniel Golle <daniel@makrotopia.org> cc: Guenter Roeck <groeck7@gmail.com> cc: Christoph Hellwig <hch@lst.de> cc: Jens Axboe <axboe@kernel.dk> cc: Al Viro <viro@zeniv.linux.org.uk> cc: John Hubbard <jhubbard@nvidia.com> cc: David Hildenbrand <david@redhat.com> cc: Matthew Wilcox <willy@infradead.org> cc: Hugh Dickins <hughd@google.com> cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/Y+pdHFFTk1TTEBsO@makrotopia.org/ [1] Link: https://lore.kernel.org/r/20230522135018.2742245-10-dhowells@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-27Merge tag 'mm-stable-2023-04-27-15-30' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of switching from a user process to a kernel thread. - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav. - zsmalloc performance improvements from Sergey Senozhatsky. - Yue Zhao has found and fixed some data race issues around the alteration of memcg userspace tunables. - VFS rationalizations from Christoph Hellwig: - removal of most of the callers of write_one_page() - make __filemap_get_folio()'s return value more useful - Luis Chamberlain has changed tmpfs so it no longer requires swap backing. Use `mount -o noswap'. - Qi Zheng has made the slab shrinkers operate locklessly, providing some scalability benefits. - Keith Busch has improved dmapool's performance, making part of its operations O(1) rather than O(n). - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd, permitting userspace to wr-protect anon memory unpopulated ptes. - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather than exclusive, and has fixed a bunch of errors which were caused by its unintuitive meaning. - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature, which causes minor faults to install a write-protected pte. - Vlastimil Babka has done some maintenance work on vma_merge(): cleanups to the kernel code and improvements to our userspace test harness. - Cleanups to do_fault_around() by Lorenzo Stoakes. - Mike Rapoport has moved a lot of initialization code out of various mm/ files and into mm/mm_init.c. - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for DRM, but DRM doesn't use it any more. - Lorenzo has also coverted read_kcore() and vread() to use iterators and has thereby removed the use of bounce buffers in some cases. - Lorenzo has also contributed further cleanups of vma_merge(). - Chaitanya Prakash provides some fixes to the mmap selftesting code. - Matthew Wilcox changes xfs and afs so they no longer take sleeping locks in ->map_page(), a step towards RCUification of pagefaults. - Suren Baghdasaryan has improved mmap_lock scalability by switching to per-VMA locking. - Frederic Weisbecker has reworked the percpu cache draining so that it no longer causes latency glitches on cpu isolated workloads. - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig logic. - Liu Shixin has changed zswap's initialization so we no longer waste a chunk of memory if zswap is not being used. - Yosry Ahmed has improved the performance of memcg statistics flushing. - David Stevens has fixed several issues involving khugepaged, userfaultfd and shmem. - Christoph Hellwig has provided some cleanup work to zram's IO-related code paths. - David Hildenbrand has fixed up some issues in the selftest code's testing of our pte state changing. - Pankaj Raghav has made page_endio() unneeded and has removed it. - Peter Xu contributed some rationalizations of the userfaultfd selftests. - Yosry Ahmed has fixed an issue around memcg's page recalim accounting. - Chaitanya Prakash has fixed some arm-related issues in the selftests/mm code. - Longlong Xia has improved the way in which KSM handles hwpoisoned pages. - Peter Xu fixes a few issues with uffd-wp at fork() time. - Stefan Roesch has changed KSM so that it may now be used on a per-process and per-cgroup basis. * tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm,unmap: avoid flushing TLB in batch if PTE is inaccessible shmem: restrict noswap option to initial user namespace mm/khugepaged: fix conflicting mods to collapse_file() sparse: remove unnecessary 0 values from rc mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area() hugetlb: pte_alloc_huge() to replace huge pte_alloc_map() maple_tree: fix allocation in mas_sparse_area() mm: do not increment pgfault stats when page fault handler retries zsmalloc: allow only one active pool compaction context selftests/mm: add new selftests for KSM mm: add new KSM process and sysfs knobs mm: add new api to enable ksm per process mm: shrinkers: fix debugfs file permissions mm: don't check VMA write permissions if the PTE/PMD indicates write permissions migrate_pages_batch: fix statistics for longterm pin retry userfaultfd: use helper function range_in_vma() lib/show_mem.c: use for_each_populated_zone() simplify code mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list() fs/buffer: convert create_page_buffers to folio_create_buffers fs/buffer: add folio_create_empty_buffers helper ...
2023-04-27shmem: restrict noswap option to initial user namespaceChristian Brauner
Prevent tmpfs instances mounted in an unprivileged namespaces from evading accounting of locked memory by using the "noswap" mount option. Link: https://lkml.kernel.org/r/20230420-faxen-advokat-40abb4c1a152@brauner Signed-off-by: Christian Brauner <brauner@kernel.org> Reported-by: Hugh Dickins <hughd@google.com> Link: https://lore.kernel.org/lkml/79eae9fe-7818-a65c-89c6-138b55d609a@google.com Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-18userfaultfd: convert mfill_atomic() to use a folioZhangPeng
Convert mfill_atomic_pte_copy(), shmem_mfill_atomic_pte() and mfill_atomic_pte() to take in a folio pointer. Convert mfill_atomic() to use a folio. Convert page_kaddr to kaddr in mfill_atomic(). Link: https://lkml.kernel.org/r/20230410133932.32288-7-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-05mm: userfaultfd: combine 'mode' and 'wp_copy' argumentsAxel Rasmussen
Many userfaultfd ioctl functions take both a 'mode' and a 'wp_copy' argument. In future commits we plan to plumb the flags through to more places, so we'd be proliferating the very long argument list even further. Let's take the time to simplify the argument list. Combine the two arguments into one - and generalize, so when we add more flags in the future, it doesn't imply more function arguments. Since the modes (copy, zeropage, continue) are mutually exclusive, store them as an integer value (0, 1, 2) in the low bits. Place combine-able flag bits in the high bits. This is quite similar to an earlier patch proposed by Nadav Amit ("userfaultfd: introduce uffd_flags" [1]). The main difference is that patch only handled flags, whereas this patch *also* combines the "mode" argument into the same type to shorten the argument list. [1]: https://lore.kernel.org/all/20220619233449.181323-2-namit@vmware.com/ Link: https://lkml.kernel.org/r/20230314221250.682452-4-axelrasmussen@google.com Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Acked-by: James Houghton <jthoughton@google.com> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-05mm: userfaultfd: don't pass around both mm and vmaAxel Rasmussen
Quite a few userfaultfd functions took both mm and vma pointers as arguments. Since the mm is trivially accessible via vma->vm_mm, there's no reason to pass both; it just needlessly extends the already long argument list. Get rid of the mm pointer, where possible, to shorten the argument list. Link: https://lkml.kernel.org/r/20230314221250.682452-3-axelrasmussen@google.com Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: James Houghton <jthoughton@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nadav Amit <namit@vmware.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-05mm: return an ERR_PTR from __filemap_get_folioChristoph Hellwig
Instead of returning NULL for all errors, distinguish between: - no entry found and not asked to allocated (-ENOENT) - failed to allocate memory (-ENOMEM) - would block (-EAGAIN) so that callers don't have to guess the error based on the passed in flags. Also pass through the error through the direct callers: filemap_get_folio, filemap_lock_folio filemap_grab_folio and filemap_get_incore_folio. [hch@lst.de: fix null-pointer deref] Link: https://lkml.kernel.org/r/20230310070023.GA13563@lst.de Link: https://lkml.kernel.org/r/20230310043137.GA1624890@u2004 Link: https://lkml.kernel.org/r/20230307143410.28031-8-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nilfs2] Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-05shmem: open code the page cache lookup in shmem_get_folio_gfpChristoph Hellwig
Use the very low level filemap_get_entry helper to look up the entry in the xarray, and then: - don't bother locking the folio if only doing a userfault notification - open code locking the page and checking for truncation in a related code block This will allow to eventually remove the FGP_ENTRY flag. [hughd@google.com: adjust the new comment line] Link: https://lkml.kernel.org/r/af178ebb-1076-a38c-1dc1-2a37ccce4a3@google.com Link: https://lkml.kernel.org/r/20230307143410.28031-6-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-05shmem: shmem_get_partial_folio use filemap_get_entryHugh Dickins
To avoid use of the FGP_ENTRY flag, adapt shmem_get_partial_folio() to use filemap_get_entry() and folio_lock() instead of __filemap_get_folio(). Update "page" in the comments there to "folio". Link: https://lkml.kernel.org/r/9d1aaa4-1337-fb81-6f37-74ebc96f9ef@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28shmem: add support to ignore swapLuis Chamberlain
In doing experimentations with shmem having the option to avoid swap becomes a useful mechanism. One of the *raves* about brd over shmem is you can avoid swap, but that's not really a good reason to use brd if we can instead use shmem. Using brd has its own good reasons to exist, but just because "tmpfs" doesn't let you do that is not a great reason to avoid it if we can easily add support for it. I don't add support for reconfiguring incompatible options, but if we really wanted to we can add support for that. To avoid swap we use mapping_set_unevictable() upon inode creation, and put a WARN_ON_ONCE() stop-gap on writepages() for reclaim. Link: https://lkml.kernel.org/r/20230309230545.2930737-7-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Christian Brauner <brauner@kernel.org> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28shmem: skip page split if we're not reclaimingLuis Chamberlain
In theory when info->flags & VM_LOCKED we should not be getting shem_writepage() called so we should be verifying this with a WARN_ON_ONCE(). Since we should not be swapping then best to ensure we also don't do the folio split earlier too. So just move the check early to avoid folio splits in case its a dubious call. We also have a similar early bail when !total_swap_pages so just move that earlier to avoid the possible folio split in the same situation. Link: https://lkml.kernel.org/r/20230309230545.2930737-5-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28shmem: move reclaim check early on writepages()Luis Chamberlain
i915_gem requires huge folios to be split when swapping. However we have check for usage of writepages() to ensure it used only for swap purposes later. Avoid the splits if we're not being called for reclaim, even if they should in theory not happen. This makes the conditions easier to follow on shem_writepage(). Link: https://lkml.kernel.org/r/20230309230545.2930737-4-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28shmem: set shmem_writepage() variables earlyLuis Chamberlain
shmem_writepage() sets up variables typically used *after* a possible huge page split. However even if that does happen the address space mapping should not change, and the inode does not change either. So it should be safe to set that from the very beginning. This commit makes no functional changes. Link: https://lkml.kernel.org/r/20230309230545.2930737-3-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28shmem: remove check for folio lock on writepage()Luis Chamberlain
Patch series "tmpfs: add the option to disable swap", v2. I'm doing this work as part of future experimentation with tmpfs and the page cache, but given a common complaint found about tmpfs is the innability to work without the page cache I figured this might be useful to others. It turns out it is -- at least Christian Brauner indicates systemd uses ramfs for a few use-cases because they don't want to use swap and so having this option would let them move over to using tmpfs for those small use cases, see systemd-creds(1). To see if you hit swap: mkswap /dev/nvme2n1 swapon /dev/nvme2n1 free -h With swap - what we see today ============================= mount -t tmpfs -o size=5G tmpfs /data-tmpfs/ dd if=/dev/urandom of=/data-tmpfs/5g-rand2 bs=1G count=5 free -h total used free shared buff/cache available Mem: 3.7Gi 2.6Gi 1.2Gi 2.2Gi 2.2Gi 1.2Gi Swap: 99Gi 2.8Gi 97Gi Without swap ============= free -h total used free shared buff/cache available Mem: 3.7Gi 387Mi 3.4Gi 2.1Mi 57Mi 3.3Gi Swap: 99Gi 0B 99Gi mount -t tmpfs -o size=5G -o noswap tmpfs /data-tmpfs/ dd if=/dev/urandom of=/data-tmpfs/5g-rand2 bs=1G count=5 free -h total used free shared buff/cache available Mem: 3.7Gi 2.6Gi 1.2Gi 2.3Gi 2.3Gi 1.1Gi Swap: 99Gi 21Mi 99Gi The mix and match remount testing ================================= # Cannot disable swap after it was first enabled: mount -t tmpfs -o size=5G tmpfs /data-tmpfs/ mount -t tmpfs -o remount -o size=5G -o noswap tmpfs /data-tmpfs/ mount: /data-tmpfs: mount point not mounted or bad option. dmesg(1) may have more information after failed mount system call. dmesg -c tmpfs: Cannot disable swap on remount # Remount with the same noswap option is OK: mount -t tmpfs -o size=5G -o noswap tmpfs /data-tmpfs/ mount -t tmpfs -o remount -o size=5G -o noswap tmpfs /data-tmpfs/ dmesg -c # Trying to enable swap with a remount after it first disabled: mount -t tmpfs -o size=5G -o noswap tmpfs /data-tmpfs/ mount -t tmpfs -o remount -o size=5G tmpfs /data-tmpfs/ mount: /data-tmpfs: mount point not mounted or bad option. dmesg(1) may have more information after failed mount system call. dmesg -c tmpfs: Cannot enable swap on remount if it was disabled on first mount This patch (of 6): Matthew notes we should not need to check the folio lock on the writepage() callback so remove it. This sanity check has been lingering since linux-history days. We remove this as we tidy up the writepage() callback to make things a bit clearer. Link: https://lkml.kernel.org/r/20230309230545.2930737-1-mcgrof@kernel.org Link: https://lkml.kernel.org/r/20230309230545.2930737-2-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Suggested-by: Matthew Wilcox <willy@infradead.org> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>