kernel/linux.git/Documentation/filesystems, branch v6.12.80

ovl: make fsync after metadata copy-up opt-in mount option

2026-04-02T11:09:50+00:00

commit 1f6ee9be92f8df85a8c9a5a78c20fd39c0c21a95 upstream. Commit 7d6899fb69d25 ("ovl: fsync after metadata copy-up") was done to fix durability of overlayfs copy up on an upper filesystem which does not enforce ordering on storing of metadata changes (e.g. ubifs). In an earlier revision of the regressing commit by Lei Lv, the metadata fsync behavior was opt-in via a new "fsync=strict" mount option. We were hoping that the opt-in mount option could be avoided, so the change was only made to depend on metacopy=off, in the hope of not hurting performance of metadata heavy workloads, which are more likely to be using metacopy=on. This hope was proven wrong by a performance regression report from Google COS workload after upgrade to kernel 6.12. This is an adaptation of Lei's original "fsync=strict" mount option to the existing upstream code. The new mount option is mutually exclusive with the "volatile" mount option, so the latter is now an alias to the "fsync=volatile" mount option. Reported-by: Chenglong Tang Closes: https://lore.kernel.org/linux-unionfs/CAOdxtTadAFH01Vui1FvWfcmQ8jH1O45owTzUcpYbNvBxnLeM7Q@mail.gmail.com/ Link: https://lore.kernel.org/linux-unionfs/CAOQ4uxgKC1SgjMWre=fUb00v8rxtd6sQi-S+dxR8oDzAuiGu8g@mail.gmail.com/ Fixes: 7d6899fb69d25 ("ovl: fsync after metadata copy-up") Depends: 50e638beb67e0 ("ovl: Use str_on_off() helper in ovl_show_options()") Cc: stable@vger.kernel.org # v6.12+ Signed-off-by: Fei Lv Signed-off-by: Amir Goldstein Signed-off-by: Greg Kroah-Hartman

nfsd: rename nfsd_serv_ prefixed methods and variables with nfsd_net_

2026-01-08T09:14:09+00:00

[ Upstream commit b33f7dec3a67216123312c7bb752b8f6faa1c465 ] Also update Documentation/filesystems/nfs/localio.rst accordingly and reduce the technical documentation debt that was previously captured in that document. Signed-off-by: Mike Snitzer Reviewed-by: Jeff Layton Acked-by: Chuck Lever Signed-off-by: Anna Schumaker Stable-dep-of: df8d829bba3a ("nfsd: fix memory leak in nfsd_create_serv error paths") Signed-off-by: Sasha Levin

nfs/localio: add direct IO enablement with sync and async IO support

2025-09-19T14:35:43+00:00

[ Upstream commit 3feec68563dda59517f83d19123aa287a1dfd068 ] This commit simply adds the required O_DIRECT plumbing. It doesn't address the fact that NFS doesn't ensure all writes are page aligned (nor device logical block size aligned as required by O_DIRECT). Because NFS will read-modify-write for IO that isn't aligned, LOCALIO will not use O_DIRECT semantics by default if/when an application requests the use of O_DIRECT. Allow the use of O_DIRECT semantics by: 1: Adding a flag to the nfs_pgio_header struct to allow the NFS O_DIRECT layer to signal that O_DIRECT was used by the application 2: Adding a 'localio_O_DIRECT_semantics' NFS module parameter that when enabled will cause LOCALIO to use O_DIRECT semantics (this may cause IO to fail if applications do not properly align their IO). This commit is derived from code developed by Weston Andros Adamson. Signed-off-by: Mike Snitzer Reviewed-by: Jeff Layton Signed-off-by: Anna Schumaker Stable-dep-of: 992203a1fba5 ("nfs/localio: restore creds before releasing pageio data") Signed-off-by: Sasha Levin

fscrypt: Don't use problematic non-inline crypto engines

2025-08-20T16:30:15+00:00

commit b41c1d8d07906786c60893980d52688f31d114a6 upstream. Make fscrypt no longer use Crypto API drivers for non-inline crypto engines, even when the Crypto API prioritizes them over CPU-based code (which unfortunately it often does). These drivers tend to be really problematic, especially for fscrypt's workload. This commit has no effect on inline crypto engines, which are different and do work well. Specifically, exclude drivers that have CRYPTO_ALG_KERN_DRIVER_ONLY or CRYPTO_ALG_ALLOCATES_MEMORY set. (Later, CRYPTO_ALG_ASYNC should be excluded too. That's omitted for now to keep this commit backportable, since until recently some CPU-based code had CRYPTO_ALG_ASYNC set.) There are two major issues with these drivers: bugs and performance. First, these drivers tend to be buggy. They're fundamentally much more error-prone and harder to test than the CPU-based code. They often don't get tested before kernel releases, and even if they do, the crypto self-tests don't properly test these drivers. Released drivers have en/decrypted or hashed data incorrectly. These bugs cause issues for fscrypt users who often didn't even want to use these drivers, e.g.: - https://github.com/google/fscryptctl/issues/32 - https://github.com/google/fscryptctl/issues/9 - https://lore.kernel.org/r/PH0PR02MB731916ECDB6C613665863B6CFFAA2@PH0PR02MB7319.namprd02.prod.outlook.com These drivers have also similarly caused issues for dm-crypt users, including data corruption and deadlocks. Since Linux v5.10, dm-crypt has disabled most of them by excluding CRYPTO_ALG_ALLOCATES_MEMORY. Second, these drivers tend to be *much* slower than the CPU-based code. This may seem counterintuitive, but benchmarks clearly show it. There's a *lot* of overhead associated with going to a hardware driver, off the CPU, and back again. To prove this, I gathered as many systems with this type of crypto engine as I could, and I measured synchronous encryption of 4096-byte messages (which matches fscrypt's workload): Intel Emerald Rapids server: AES-256-XTS: xts-aes-vaes-avx512 16171 MB/s [CPU-based, Vector AES] qat_aes_xts 289 MB/s [Offload, Intel QuickAssist] Qualcomm SM8650 HDK: AES-256-XTS: xts-aes-ce 4301 MB/s [CPU-based, ARMv8 Crypto Extensions] xts-aes-qce 73 MB/s [Offload, Qualcomm Crypto Engine] i.MX 8M Nano LPDDR4 EVK: AES-256-XTS: xts-aes-ce 647 MB/s [CPU-based, ARMv8 Crypto Extensions] xts(ecb-aes-caam) 20 MB/s [Offload, CAAM] AES-128-CBC-ESSIV: essiv(cbc-aes-caam,sha256-lib) 23 MB/s [Offload, CAAM] STM32MP157F-DK2: AES-256-XTS: xts-aes-neonbs 13.2 MB/s [CPU-based, ARM NEON] xts(stm32-ecb-aes) 3.1 MB/s [Offload, STM32 crypto engine] AES-128-CBC-ESSIV: essiv(cbc-aes-neonbs,sha256-lib) 14.7 MB/s [CPU-based, ARM NEON] essiv(stm32-cbc-aes,sha256-lib) 3.2 MB/s [Offload, STM32 crypto engine] Adiantum: adiantum(xchacha12-arm,aes-arm,nhpoly1305-neon) 52.8 MB/s [CPU-based, ARM scalar + NEON] So, there was no case in which the crypto engine was even *close* to being faster. On the first three, which have AES instructions in the CPU, the CPU was 30 to 55 times faster (!). Even on STM32MP157F-DK2 which has a Cortex-A7 CPU that doesn't have AES instructions, AES was over 4 times faster on the CPU. And Adiantum encryption, which is what actually should be used on CPUs like that, was over 17 times faster. Other justifications that have been given for these non-inline crypto engines (almost always coming from the hardware vendors, not actual users) don't seem very plausible either: - The crypto engine throughput could be improved by processing multiple requests concurrently. Currently irrelevant to fscrypt, since it doesn't do that. This would also be complex, and unhelpful in many cases. 2 of the 4 engines I tested even had only one queue. - Some of the engines, e.g. STM32, support hardware keys. Also currently irrelevant to fscrypt, since it doesn't support these. Interestingly, the STM32 driver itself doesn't support this either. - Free up CPU for other tasks and/or reduce energy usage. Not very plausible considering the "short" message length, driver overhead, and scheduling overhead. There's just very little time for the CPU to do something else like run another task or enter low-power state, before the message finishes and it's time to process the next one. - Some of these engines resist power analysis and electromagnetic attacks, while the CPU-based crypto generally does not. In theory, this sounds great. In practice, if this benefit requires the use of an off-CPU offload that massively regresses performance and has a low-quality, buggy driver, the price for this hardening (which is not relevant to most fscrypt users, and tends to be incomplete) is just too high. Inline crypto engines are much more promising here, as are on-CPU solutions like RISC-V High Assurance Cryptography. Fixes: b30ab0e03407 ("ext4 crypto: add ext4 encryption facilities") Cc: stable@vger.kernel.org Acked-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20250704070322.20692-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

f2fs: doc: fix wrong quota mount option description

2025-08-15T10:14:01+00:00

[ Upstream commit 81b6ecca2f15922e8d653dc037df5871e754be6e ] We should use "{usr,grp,prj}jquota=" to disable journaled quota, rather than using off{usr,grp,prj}jquota. Fixes: 4b2414d04e99 ("f2fs: support journalled quota") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin

fs_parser: update mount_api doc to match function signature

2024-12-05T13:02:29+00:00

[ Upstream commit c66f759832a83cb273ba5a55c66dcc99384efa74 ] Add the missing 'name' parameter to the mount_api documentation for fs_validate_description(). Fixes: 96cafb9ccb15 ("fs_parser: remove fs_parameter_description name field") Signed-off-by: Randy Dunlap Link: https://lore.kernel.org/r/20241125215021.231758-1-rdunlap@infradead.org Cc: Eric Sandeen Cc: David Howells Cc: Al Viro Cc: Christian Brauner Cc: Jan Kara Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

Merge tag 'vfs-6.12-rc6.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

2024-11-01T17:37:10+00:00

Pull filesystem fixes from Christian Brauner: "VFS: - Fix copy_page_from_iter_atomic() if KMAP_LOCAL_FORCE_MAP=y is set - Add a get_tree_bdev_flags() helper that allows to modify e.g., whether errors are logged into the filesystem context during superblock creation. This is used by erofs to fix a userspace regression where an error is currently logged when its used on a regular file which is an new allowed mode in erofs. netfs: - Fix the sysfs debug path in the documentation. - Fix iov_iter_get_pages*() for folio queues by skipping the page extracation if we're at the end of a folio. afs: - Fix moving subdirectories to different parent directory. autofs: - Fix handling of AUTOFS_DEV_IOCTL_TIMEOUT_CMD ioctl in validate_dev_ioctl(). The actual ioctl number, not the ioctl command needs to be checked for autofs" * tag 'vfs-6.12-rc6.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: iov_iter: fix copy_page_from_iter_atomic() if KMAP_LOCAL_FORCE_MAP autofs: fix thinko in validate_dev_ioctl() iov_iter: Fix iov_iter_get_pages*() for folio_queue afs: Fix missing subdir edit when renamed between parent dirs doc: correcting the debug path for cachefiles erofs: use get_tree_bdev_flags() to avoid misleading messages fs/super.c: introduce get_tree_bdev_flags()

doc: correcting the debug path for cachefiles

2024-10-24T11:50:27+00:00

The original debug path is under "/sys/modules", that's wrong. The real path in kernel is "/sys/module". So we can correct it. Signed-off-by: Hongbo Li Link: https://lore.kernel.org/r/20241022013812.2880883-1-lihongbo22@huawei.com Signed-off-by: Christian Brauner

Merge tag 'vfs-6.12-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-10-21T17:48:24+00:00

Pull vfs fixes from Christian Brauner: "afs: - Fix a lock recursion in afs_wake_up_async_call() on ->notify_lock netfs: - Drop the references to a folio immediately after the folio has been extracted to prevent races with future I/O collection - Fix a documenation build error - Downgrade the i_rwsem for buffered writes to fix a cifs reported performance regression when switching to netfslib vfs: - Explicitly return -E2BIG from openat2() if the specified size is unexpectedly large. This aligns openat2() with other extensible struct based system calls - When copying a mount namespace ensure that we only try to remove the new copy from the mount namespace rbtree if it has already been added to it nilfs: - Clear the buffer delay flag when clearing the buffer state clags when a buffer head is discarded to prevent a kernel OOPs ocfs2: - Fix an unitialized value warning in ocfs2_setattr() proc: - Fix a kernel doc warning" * tag 'vfs-6.12-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: proc: Fix W=1 build kernel-doc warning afs: Fix lock recursion fs: Fix uninitialized value issue in from_kuid and from_kgid fs: don't try and remove empty rbtree node netfs: Downgrade i_rwsem for a buffered write nilfs2: fix kernel bug due to missing clearing of buffer delay flag openat2: explicitly return -E2BIG for (usize > PAGE_SIZE) netfs: fix documentation build error netfs: In readahead, put the folio refs as soon extracted

iomap: remove iomap_file_buffered_write_punch_delalloc

2024-10-15T09:37:42+00:00

Currently iomap_file_buffered_write_punch_delalloc can be called from XFS either with the invalidate lock held or not. To fix this while keeping the locking in the file system and not the iomap library code we'll need to life the locking up into the file system. To prepare for that, open code iomap_file_buffered_write_punch_delalloc in the only caller, and instead export iomap_write_delalloc_release. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Carlos Maiolino