kernel.git/Documentation/filesystems, branch linux-6.15.y

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

2025-08-20T16:35:45Z

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

2025-08-15T10:16:53Z

[ 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

Merge tag 'ext4_for_linus-6.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2025-04-13T14:15:50Z

Pull ext4 fixes from Ted Ts'o: "A few more miscellaneous ext4 bug fixes and cleanups including some syzbot failures and fixing a stale file handing refeencing an inode previously used as a regular file, but which has been deleted and reused as an ea_inode would result in ext4 erroneously considering this a case of fs corruption" * tag 'ext4_for_linus-6.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: fix off-by-one error in do_split ext4: make block validity check resistent to sb bh corruption ext4: avoid -Wflex-array-member-not-at-end warning Documentation: ext4: Add fields to ext4_super_block documentation ext4: don't treat fhandle lookup of ea_inode as FS corruption

Documentation: ext4: Add fields to ext4_super_block documentation

2025-04-13T01:50:41Z

Documentation and implementation of the ext4 super block have slightly diverged: Padding has been removed in order to make room for new fields that are still missing in the documentation. Add the new fields s_encryption_level, s_first_error_errorcode, s_last_error_errorcode to the documentation of the ext4 super block. Fixes: f542fbe8d5e8 ("ext4 crypto: reserve codepoints used by the ext4 encryption feature") Fixes: 878520ac45f9 ("ext4: save the error code which triggered an ext4_error() in the superblock") Signed-off-by: Tom Vierjahn Reviewed-by: Ojaswin Mujoo Link: https://patch.msgid.link/20250324221004.5268-1-tom.vierjahn@acm.org Signed-off-by: Theodore Ts'o

Merge tag '9p-for-6.15-rc1' of https://github.com/martinetd/linux

2025-04-03T22:35:46Z

Pull 9p updates from Dominique Martinet: - fix handling of bogus (negative/too long) replies - fix crash on mkdir with ACLs (... looks like nobody is using ACLs with semi-recent kernels...) - ipv6 support for trans=tcp - minor concurrency fix to make syzbot happy - minor cleanup * tag '9p-for-6.15-rc1' of https://github.com/martinetd/linux: docs: fs/9p: Add missing "not" in cache documentation 9p: Use hashtable.h for hash_errmap Documentation/fs/9p: fix broken link 9p/trans_fd: mark concurrent read and writes to p9_conn->err 9p/net: return error on bogus (longer than requested) replies 9p/net: fix improper handling of bogus negative read/write replies fs/9p: fix NULL pointer dereference on mkdir net/9p/fd: support ipv6 for trans=tcp

docs: fs/9p: Add missing "not" in cache documentation

2025-04-03T03:31:11Z

A quick fix for what I assume is a typo. Signed-off-by: Tingmao Wang Reviewed-by: Christian Schoenebeck Message-ID: <20250330213443.98434-1-m@maowtm.org> Signed-off-by: Dominique Martinet

Merge tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-04-01T17:06:52Z

Pull non-MM updates from Andrew Morton: - The series "powerpc/crash: use generic crashkernel reservation" from Sourabh Jain changes powerpc's kexec code to use more of the generic layers. - The series "get_maintainer: report subsystem status separately" from Vlastimil Babka makes some long-requested improvements to the get_maintainer output. - The series "ucount: Simplify refcounting with rcuref_t" from Sebastian Siewior cleans up and optimizing the refcounting in the ucount code. - The series "reboot: support runtime configuration of emergency hw_protection action" from Ahmad Fatoum improves the ability for a driver to perform an emergency system shutdown or reboot. - The series "Converge on using secs_to_jiffies() part two" from Easwar Hariharan performs further migrations from msecs_to_jiffies() to secs_to_jiffies(). - The series "lib/interval_tree: add some test cases and cleanup" from Wei Yang permits more userspace testing of kernel library code, adds some more tests and performs some cleanups. - The series "hung_task: Dump the blocking task stacktrace" from Masami Hiramatsu arranges for the hung_task detector to dump the stack of the blocking task and not just that of the blocked task. - The series "resource: Split and use DEFINE_RES*() macros" from Andy Shevchenko provides some cleanups to the resource definition macros. - Plus the usual shower of singleton patches - please see the individual changelogs for details. * tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits) mailmap: consolidate email addresses of Alexander Sverdlin fs/procfs: fix the comment above proc_pid_wchan() relay: use kasprintf() instead of fixed buffer formatting resource: replace open coded variant of DEFINE_RES() resource: replace open coded variants of DEFINE_RES_*_NAMED() resource: replace open coded variant of DEFINE_RES_NAMED_DESC() resource: split DEFINE_RES_NAMED_DESC() out of DEFINE_RES_NAMED() samples: add hung_task detector mutex blocking sample hung_task: show the blocker task if the task is hung on mutex kexec_core: accept unaccepted kexec segments' destination addresses watchdog/perf: optimize bytes copied and remove manual NUL-termination lib/interval_tree: fix the comment of interval_tree_span_iter_next_gap() lib/interval_tree: skip the check before go to the right subtree lib/interval_tree: add test case for span iteration lib/interval_tree: add test case for interval_tree_iter_xxx() helpers lib/rbtree: add random seed lib/rbtree: split tests lib/rbtree: enable userland test suite for rbtree related data structure checkpatch: describe --min-conf-desc-length scripts/gdb/symbols: determine KASLR offset on s390 ...

Merge tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-04-01T16:29:18Z

Pull MM updates from Andrew Morton: - The series "Enable strict percpu address space checks" from Uros Bizjak uses x86 named address space qualifiers to provide compile-time checking of percpu area accesses. This has caused a small amount of fallout - two or three issues were reported. In all cases the calling code was found to be incorrect. - The series "Some cleanup for memcg" from Chen Ridong implements some relatively monir cleanups for the memcontrol code. - The series "mm: fixes for device-exclusive entries (hmm)" from David Hildenbrand fixes a boatload of issues which David found then using device-exclusive PTE entries when THP is enabled. More work is needed, but this makes thins better - our own HMM selftests now succeed. - The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed remove the z3fold and zbud implementations. They have been deprecated for half a year and nobody has complained. - The series "mm: further simplify VMA merge operation" from Lorenzo Stoakes implements numerous simplifications in this area. No runtime effects are anticipated. - The series "mm/madvise: remove redundant mmap_lock operations from process_madvise()" from SeongJae Park rationalizes the locking in the madvise() implementation. Performance gains of 20-25% were observed in one MADV_DONTNEED microbenchmark. - The series "Tiny cleanup and improvements about SWAP code" from Baoquan He contains a number of touchups to issues which Baoquan noticed when working on the swap code. - The series "mm: kmemleak: Usability improvements" from Catalin Marinas implements a couple of improvements to the kmemleak user-visible output. - The series "mm/damon/paddr: fix large folios access and schemes handling" from Usama Arif provides a couple of fixes for DAMON's handling of large folios. - The series "mm/damon/core: fix wrong and/or useless damos_walk() behaviors" from SeongJae Park fixes a few issues with the accuracy of kdamond's walking of DAMON regions. - The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo Stoakes changes the interaction between framebuffer deferred-io and core MM. No functional changes are anticipated - this is preparatory work for the future removal of page structure fields. - The series "mm/damon: add support for hugepage_size DAMOS filter" from Usama Arif adds a DAMOS filter which permits the filtering by huge page sizes. - The series "mm: permit guard regions for file-backed/shmem mappings" from Lorenzo Stoakes extends the guard region feature from its present "anon mappings only" state. The feature now covers shmem and file-backed mappings. - The series "mm: batched unmap lazyfree large folios during reclamation" from Barry Song cleans up and speeds up the unmapping for pte-mapped large folios. - The series "reimplement per-vma lock as a refcount" from Suren Baghdasaryan puts the vm_lock back into the vma. Our reasons for pulling it out were largely bogus and that change made the code more messy. This patchset provides small (0-10%) improvements on one microbenchmark. - The series "Docs/mm/damon: misc DAMOS filters documentation fixes and improves" from SeongJae Park does some maintenance work on the DAMON docs. - The series "hugetlb/CMA improvements for large systems" from Frank van der Linden addresses a pile of issues which have been observed when using CMA on large machines. - The series "mm/damon: introduce DAMOS filter type for unmapped pages" from SeongJae Park enables users of DMAON/DAMOS to filter my the page's mapped/unmapped status. - The series "zsmalloc/zram: there be preemption" from Sergey Senozhatsky teaches zram to run its compression and decompression operations preemptibly. - The series "selftests/mm: Some cleanups from trying to run them" from Brendan Jackman fixes a pile of unrelated issues which Brendan encountered while runnimg our selftests. - The series "fs/proc/task_mmu: add guard region bit to pagemap" from Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to determine whether a particular page is a guard page. - The series "mm, swap: remove swap slot cache" from Kairui Song removes the swap slot cache from the allocation path - it simply wasn't being effective. - The series "mm: cleanups for device-exclusive entries (hmm)" from David Hildenbrand implements a number of unrelated cleanups in this code. - The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual implements a number of preparatoty cleanups to the GENERIC_PTDUMP Kconfig logic. - The series "mm/damon: auto-tune aggregation interval" from SeongJae Park implements a feedback-driven automatic tuning feature for DAMON's aggregation interval tuning. - The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in powerpc, sparc and x86 lazy MMU implementations. Ryan did this in preparation for implementing lazy mmu mode for arm64 to optimize vmalloc. - The series "mm/page_alloc: Some clarifications for migratetype fallback" from Brendan Jackman reworks some commentary to make the code easier to follow. - The series "page_counter cleanup and size reduction" from Shakeel Butt cleans up the page_counter code and fixes a size increase which we accidentally added late last year. - The series "Add a command line option that enables control of how many threads should be used to allocate huge pages" from Thomas Prescher does that. It allows the careful operator to significantly reduce boot time by tuning the parallalization of huge page initialization. - The series "Fix calculations in trace_balance_dirty_pages() for cgwb" from Tang Yizhou fixes the tracing output from the dirty page balancing code. - The series "mm/damon: make allow filters after reject filters useful and intuitive" from SeongJae Park improves the handling of allow and reject filters. Behaviour is made more consistent and the documention is updated accordingly. - The series "Switch zswap to object read/write APIs" from Yosry Ahmed updates zswap to the new object read/write APIs and thus permits the removal of some legacy code from zpool and zsmalloc. - The series "Some trivial cleanups for shmem" from Baolin Wang does as it claims. - The series "fs/dax: Fix ZONE_DEVICE page reference counts" from Alistair Popple regularizes the weird ZONE_DEVICE page refcount handling in DAX, permittig the removal of a number of special-case checks. - The series "refactor mremap and fix bug" from Lorenzo Stoakes is a preparatoty refactoring and cleanup of the mremap() code. - The series "mm: MM owner tracking for large folios (!hugetlb) + CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in which we determine whether a large folio is known to be mapped exclusively into a single MM. - The series "mm/damon: add sysfs dirs for managing DAMOS filters based on handling layers" from SeongJae Park adds a couple of new sysfs directories to ease the management of DAMON/DAMOS filters. - The series "arch, mm: reduce code duplication in mem_init()" from Mike Rapoport consolidates many per-arch implementations of mem_init() into code generic code, where that is practical. - The series "mm/damon/sysfs: commit parameters online via damon_call()" from SeongJae Park continues the cleaning up of sysfs access to DAMON internal data. - The series "mm: page_ext: Introduce new iteration API" from Luiz Capitulino reworks the page_ext initialization to fix a boot-time crash which was observed with an unusual combination of compile and cmdline options. - The series "Buddy allocator like (or non-uniform) folio split" from Zi Yan reworks the code to split a folio into smaller folios. The main benefit is lessened memory consumption: fewer post-split folios are generated. - The series "Minimize xa_node allocation during xarry split" from Zi Yan reduces the number of xarray xa_nodes which are generated during an xarray split. - The series "drivers/base/memory: Two cleanups" from Gavin Shan performs some maintenance work on the drivers/base/memory code. - The series "Add tracepoints for lowmem reserves, watermarks and totalreserve_pages" from Martin Liu adds some more tracepoints to the page allocator code. - The series "mm/madvise: cleanup requests validations and classifications" from SeongJae Park cleans up some warts which SeongJae observed during his earlier madvise work. - The series "mm/hwpoison: Fix regressions in memory failure handling" from Shuai Xue addresses two quite serious regressions which Shuai has observed in the memory-failure implementation. - The series "mm: reliable huge page allocator" from Johannes Weiner makes huge page allocations cheaper and more reliable by reducing fragmentation. - The series "Minor memcg cleanups & prep for memdescs" from Matthew Wilcox is preparatory work for the future implementation of memdescs. - The series "track memory used by balloon drivers" from Nico Pache introduces a way to track memory used by our various balloon drivers. - The series "mm/damon: introduce DAMOS filter type for active pages" from Nhat Pham permits users to filter for active/inactive pages, separately for file and anon pages. - The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia separates the proactive reclaim statistics from the direct reclaim statistics. - The series "mm/vmscan: don't try to reclaim hwpoison folio" from Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim code. * tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits) mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex() x86/mm: restore early initialization of high_memory for 32-bits mm/vmscan: don't try to reclaim hwpoison folio mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper cgroup: docs: add pswpin and pswpout items in cgroup v2 doc mm: vmscan: split proactive reclaim statistics from direct reclaim statistics selftests/mm: speed up split_huge_page_test selftests/mm: uffd-unit-tests support for hugepages > 2M docs/mm/damon/design: document active DAMOS filter type mm/damon: implement a new DAMOS filter type for active pages fs/dax: don't disassociate zero page entries MM documentation: add "Unaccepted" meminfo entry selftests/mm: add commentary about 9pfs bugs fork: use __vmalloc_node() for stack allocation docs/mm: Physical Memory: Populate the "Zones" section xen: balloon: update the NR_BALLOON_PAGES state hv_balloon: update the NR_BALLOON_PAGES state balloon_compaction: update the NR_BALLOON_PAGES state meminfo: add a per node counter for balloon drivers mm: remove references to folio in __memcg_kmem_uncharge_page() ...

Merge tag 'nfsd-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

2025-04-01T00:28:17Z

Pull nfsd updates from Chuck Lever: "Neil Brown contributed more scalability improvements to NFSD's open file cache, and Jeff Layton contributed a menagerie of repairs to NFSD's NFSv4 callback / backchannel implementation. Mike Snitzer contributed a change to NFS re-export support that disables support for file locking on a re-exported NFSv4 mount. This is because NFSv4 state recovery is currently difficult if not impossible for re-exported NFS mounts. The change aims to prevent data integrity exposures after the re-export server crashes. Work continues on the evolving NFSD netlink administrative API. Many thanks to the contributors, reviewers, testers, and bug reporters who participated during the v6.15 development cycle" * tag 'nfsd-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (45 commits) NFSD: Add a Kconfig setting to enable delegated timestamps sysctl: Fixes nsm_local_state bounds nfsd: use a long for the count in nfsd4_state_shrinker_count() nfsd: remove obsolete comment from nfs4_alloc_stid nfsd: remove unneeded forward declaration of nfsd4_mark_cb_fault() nfsd: reorganize struct nfs4_delegation for better packing nfsd: handle errors from rpc_call_async() nfsd: move cb_need_restart flag into cb_flags nfsd: replace CB_GETATTR_BUSY with NFSD4_CALLBACK_RUNNING nfsd: eliminate cl_ra_cblist and NFSD4_CLIENT_CB_RECALL_ANY nfsd: prevent callback tasks running concurrently nfsd: disallow file locking and delegations for NFSv4 reexport nfsd: filecache: drop the list_lru lock during lock gc scans nfsd: filecache: don't repeatedly add/remove files on the lru list nfsd: filecache: introduce NFSD_FILE_RECENT nfsd: filecache: use list_lru_walk_node() in nfsd_file_gc() nfsd: filecache: use nfsd_file_dispose_list() in nfsd_file_close_inode_sync() NFSD: Re-organize nfsd_file_gc_worker() nfsd: filecache: remove race handling. fs: nfs: acl: Avoid -Wflex-array-member-not-at-end warning ...

Merge tag 'ext4-for_linus-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2025-03-27T20:27:08Z

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 ...