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2026-08-20Merge tag 'ext4_for_linus-7.3-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: - Improve performance by allowing parallel DIO writes when we were previously being overly conservative when checking whether it was safe to avoid requiring an exclusive lock - Improve the performance of ext4_mb_prefetch() used by fallocate() by avoiding work when it is not needed - Remove the unnecessary custom end_io function ext4_end_buffer_io_sync() - Improve performance when performing an overwrite to an already uptodate folio - Clean up how we handle deallocating EA inodes to avoid a potential lock ordering issue when there is a failed mount while an EA inode is still being evicted - Use str_plural() instead of a custom macro - Avoid soft lockups or RCU stalls if there are many busy buffers (caused by heavy I/O) while checkpointing - Use scoped NOFS when starting a handle in nojournal mode - Align fields in handle structure to optimize setting and getting the h_type and h_line_no fields - Fix documentation of the meta_bg block group layout - Bug fixes: - Fix a potential out-of-bounds read in ext4_read_inline_dir() - Fix a potential deadlock when concurrent xattr operations are racing with each other when some of the xattrs are using the ea_inode feature - Fix a spurious warning with data=journal that can be triggered when writeback races with remounting the file system read-only - Fix a potential deadlock when EXT4_IOC_MIGRATE races with a file system freeze operation - Make sure all in-flight direct I/O operations are complete before falling back to buffered I/O - Handle IOCB_NOWAIT properly when performing a extending DAX write - Prevent potentially sleeping on a block allocation when IOCB_NOWAIT is set - Fix potential races when racing an inline data write with a page fault - Propagate errors when adding or removing extent ranges during a fast commit replay - Avoid trying to expand an inode's extra size when it is being evicted to avoid a number of corner case or deadlocks - Avoid spurious error when retrying inode extra size expansion - Fix corner cases where we underestimate the number of journal credits needed - Avoid hangs/crashes/WARNINGS caused by maliciously corrupted file systems - Don't issue spurious orphan clean message on RO file systems - Avoid leaving the file system in an inconsistent state after a crash when a WRITE_ZEROS in progress converting an unwritten extent to a written extent - Handle WRITE_ZEROS correctly when there are some partially dirtied regions in the page cache - Pass errors during zero-rage, truncate, or punch hole to the caller if ext4_get_block() fails - Wait for writeback to finish when triggered by zero-range or zero-range for those devices that require stable writes - If the reserved gid superblock field is set, set the reserved gid instead of the reserved uid * tag 'ext4_for_linus-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (56 commits) ext4: fix estimate extent index blocks in ext4_ext_index_trans_blocks() ext4: fix transaction overflow during writeback ext4: teach ext4_meta_trans_blocks() about number of allocated extents ext4: guard against NULL s_group_info in ext4_get_group_info ext4: fix spurious message about orphan cleanup on RO fs ext4: stop retrying saturated xattr cache entries ext4: don't enable DAX on new encrypted files ext4: protect WRITE_ZEROES written extents with orphan list ext4: export converted block count from ext4_convert_unwritten_extents() ext4: fix incorrect function call when initializing s_resgid ext4: validate EA inode i_nlink in ext4_xattr_inode_iget jbd2: align h_type and h_line_no in the handle structure on byte boundaries ext4: enable scoped NOFS when starting a handle in nojournal mode ext4: write back partial-zeroed edges in WRITE_ZEROES ext4: zero out whole block for clean edges in WRITE_ZEROES ext4: track partial-zero outcome per edge in ext4_zero_partial_blocks() ext4: clarify return semantics of ext4_load_tail_bh() ext4: move partial block zeroing earlier in ext4_zero_range() ext4: check return value of ext4_get_block() in ext4_load_tail_bh() ext4: skip tail block zeroing for inline data files ...
2026-07-31iomap: decouple simple direct I/O reads from iomap_dio_rwChristoph Hellwig
The pending iomap_iter_next conversion creates performance issues for the new simple direct I/O read fast path, because it assumes a model where the iterator must be advanced at the end, which the direct I/O read fast path tries to avoid. Side step this by splitting the simple path from iomap_dio_rw, and require the file systems to call into it explicitly, and pass only a ->begin callback. This allows to drop various checks for incompatible features while creating a requirement for the file system to only call the simple path for cases that it can handle. As a side-benefit we can now inline the initial part of the simple direct I/O read fast path and let the compiler convert the indirect call to ->begin into a direct call. Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Fengnan Chang <changfengnan@bytedance.com> Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/20260729192737.3190206-4-joannelkoong@gmail.com Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-07-30ext4: export converted block count from ext4_convert_unwritten_extents()Zhang Yi
ext4_convert_unwritten_extents() currently returns only a success or a failure indication. A zero return means all requested blocks were converted, and a negative value means the conversion failed. However, some blocks may have already been converted when the function fails partway through, and callers have no way to learn how many were done. The WRITE_ZEROES caller in ext4_alloc_file_blocks() needs this information to decide whether to add the inode to the orphan list before updating i_disksize to cover the already-converted written extents, so that a crash before i_disksize catches up can be recovered via orphan truncation. Switch the function to pass out the number of converted blocks through the new output parameter @converted, which will be used by later patches. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20260729085918.3336221-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-07-22ext4: fix NOWAIT semantic violation in DAX extending writesBaokun Li
When a DAX write starts before EOF but extends past i_disksize, ext4_write_checks() skips the IOCB_NOWAIT check because iocb->ki_pos <= old_size. However, ext4_dax_write_iter() later calls ext4_journal_start() to prepare for inode extension, which can sleep waiting for journal space or transaction commit. This violates NOWAIT semantics and can stall asynchronous I/O frameworks like io_uring that rely on non-blocking behavior. Fix this by checking IOCB_NOWAIT before calling ext4_journal_start() in the extending write path. If NOWAIT is set and extension is needed, return -EAGAIN so the caller can retry in blocking context. Example scenario: - File: i_size = 1000, i_disksize = 1000 - DAX NOWAIT write: offset = 500, count = 2000 - ext4_write_checks(): ki_pos (500) <= old_size (1000), skip NOWAIT check - ext4_dax_write_iter(): offset + count (2500) > i_disksize (1000) - ext4_journal_start() → may sleep → violates NOWAIT Reported-by: Sashiko <sashiko-bot@kernel.org> Closes: https://sashiko.dev/#/patchset/20260618125735.4156639-1-libaokun@linux.alibaba.com?part=5 Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20260629113827.4074335-7-libaokun@linux.alibaba.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-07-22ext4: use kiocb_modified instead of file_modified in DIO/DAX write pathBaokun Li
file_modified() passes flags=0 which drops IOCB_NOWAIT, causing file_update_time() to sleep in ext4_journal_start() via ext4_dirty_inode() even in non-blocking contexts. kiocb_modified(iocb) propagates iocb->ki_flags so that generic_update_time() correctly returns -EAGAIN when IOCB_NOWAIT is set and ->dirty_inode could block, matching the behavior already adopted by XFS, FUSE, and ext2. Affected paths: - ext4_dio_write_checks(): DIO NOWAIT write - ext4_write_checks(): shared by buffered (rejects NOWAIT upfront) and DAX write (supports NOWAIT) ext4_fallocate() in extents.c is not affected as it has no kiocb. Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com> Link: https://patch.msgid.link/20260629113827.4074335-6-libaokun@linux.alibaba.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-07-22ext4: base unaligned DIO lock decision on partial block zeroingBaokun Li
For unaligned DIO writes, the previous ext4_overwrite_io() required the entire range to fall within a single written extent. This was overly conservative: the DIO layer only performs partial block zeroing for the head and tail blocks when they are partially covered by the write. Middle blocks that are fully covered are written as whole blocks without any zeroing, so they are safe regardless of extent state. Therefore exclusive lock is only required when partial block zeroing will actually happen: - The head partial block (if any) lands on a hole or unwritten extent. - The tail partial block (if any) lands on a hole or unwritten extent. Middle full-cover blocks can be in any state (hole, unwritten, or written) - block allocation under shared lock is safe per the previous patch's analysis (inode_dio_begin + i_data_sem protection). Replace ext4_overwrite_io() with ext4_dio_needs_zeroing(), which directly answers the question driving the lock decision. It uses at most two ext4_map_blocks() calls: one for the head partial block (also catching the case where it spans through the tail), and one for the tail partial block if not already covered. This enables shared lock for previously-rejected scenarios such as: - Unaligned write spanning written extent + mid-range hole + written extent at the tail. - Unaligned write where the partial blocks land on written extents but the middle has unwritten extents. Performance: Hardware: /dev/sda (rotational disk, ~1 GB/s sustained write) Filesystem: ext4 default mkfs Unaligned DIO writes (14336 bytes at +512 within each 16K stripe). Each stripe is laid out as [written][unwritten][unwritten][written], so the head and tail partial blocks land on written extents but the middle is unwritten. Metric: IOPS. JOBS Before After speedup ---- -------- --------- ------- 1 15,547 17,381 1.12x 2 15,910 34,172 2.15x 4 15,014 57,567 3.83x 8 15,022 81,947 5.46x 16 14,586 99,126 6.80x 32 14,047 92,519 6.59x Wall time at JOBS=32: 149.3s (Before) -> 22.7s (After), 6.58x faster. Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com> Link: https://patch.msgid.link/20260629113827.4074335-5-libaokun@linux.alibaba.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-07-22ext4: skip overwrite check for aligned non-extending DIO writesBaokun Li
Currently, ext4_dio_write_checks() calls ext4_overwrite_io() to determine if a write is a pure overwrite, and upgrades to exclusive i_rwsem if not. However, ext4_overwrite_io() uses a single ext4_map_blocks() call which only returns the first contiguous extent of the same type. A write spanning multiple pre-allocated extents (e.g. written + unwritten, or two physically discontiguous written extents) produces a false negative, forcing an unnecessary exclusive lock upgrade. After commit 5d87c7fca2c1 ("ext4: avoid starting handle when dio writing an unwritten extent") and commit 012924f0eeef ("ext4: remove useless ext4_iomap_overwrite_ops"), ext4_iomap_begin()'s fast path accepts both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN without starting a journal transaction. The iomap iteration naturally handles multi-extent ranges: each call returns the mapping for the current segment, and unwritten-to-written conversion is deferred to ext4_dio_write_end_io(). This means the common case of mixed written/unwritten extents never reaches ext4_iomap_alloc() at all. Even for the less common case where the range contains a hole and ext4_iomap_alloc() is needed, exclusive i_rwsem is still unnecessary for aligned non-extending writes: - truncate/punch_hole are kept out: they require exclusive i_rwsem (blocked by our shared lock during allocation), and inode_dio_begin() keeps their inode_dio_wait() blocked until in-flight bios complete. - i_data_sem write-lock inside ext4_map_blocks() serializes concurrent extent tree modifications (parallel writers to the same hole). - The journal handle is per-thread and does not require i_rwsem exclusion. - i_disksize and orphan list are not involved in non-extending writes. Skip the ext4_overwrite_io() check entirely for aligned writes by initializing overwrite to true and only calling ext4_overwrite_io() for unaligned writes. Unaligned writes still need the extent state check because concurrent partial block zeroing in the DIO layer requires exclusive serialization unless the range is a pure written-extent overwrite. Performance: Hardware: /dev/sda (rotational disk, ~1 GB/s sustained write) Filesystem: ext4 default mkfs Aligned 8K DIO writes spanning written+unwritten extent boundaries. Each thread writes its own 1G region sequentially; the file is rebuilt between runs so every block is written exactly once. Metric: IOPS. JOBS Before After speedup ---- -------- --------- ------- 1 42,322 43,329 1.02x 2 68,516 70,677 1.03x 4 62,489 97,072 1.55x 8 58,701 110,819 1.89x 16 58,569 116,392 1.99x 32 60,860 117,244 1.93x Wall time at JOBS=32: 69.2s (Before) -> 35.4s (After), 1.96x faster. Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com> Link: https://patch.msgid.link/20260629113827.4074335-4-libaokun@linux.alibaba.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-07-22ext4: drain in-flight DIO before buffered write fallbackBaokun Li
generic/746 started failing intermittently on ext3 (no-extent inodes). The test triggers 'Page cache invalidation failure on direct I/O' warnings and subsequent fsync returns -EIO. Adding a 50ms delay between ext4_buffered_write_iter() and filemap_write_and_wait_range() in ext4_dio_write_iter() makes the race almost always reproducible. On no-extent inodes, DIO writes to holes cannot use unwritten extents, so ext4_iomap_alloc() leaves m_flags=0 and ext4_map_blocks() returns 0. The iomap layer then returns -ENOTBLK, causing fallback to buffered I/O. The fallback path in ext4_dio_write_iter() calls ext4_buffered_write_iter() which dirties pages, then does flush and invalidate. However, there's an unprotected window between ext4_buffered_write_iter() returning (with inode lock released) and the subsequent flush+invalidate. Concurrent async DIO completions from other threads can run kiocb_invalidate_post_direct_write() during this window. If pages have been re-dirtied, post-invalidation finds dirty pages and triggers the warning, setting -EIO in the error sequence. Consider a file with two 4k extents: [hole][written]. Thread A does DIO to the written extent, while thread B does DIO spanning both: kworker A (4k DIO, allocated block) kworker B (8k DIO, fallback) ----------------------------------- ---------------------------- inode_lock_shared() inode_lock_shared() iomap_dio_rw(): iomap_dio_rw(): kiocb_invalidate_pages -> clean iomap_begin -> -ENOTBLK submit_bio (async) dio->size = 0 inode_unlock_shared() inode_unlock_shared() [bio pending in block layer] /* fallback: lock released */ ext4_buffered_write_iter() inode_lock(exclusive) generic_perform_write() -> dirty pages [0, 8k] inode_unlock(exclusive) /* pages dirty, no lock */ [bio completes] filemap_write_and_wait_range() iomap_dio_complete() -> flush dirty pages kiocb_invalidate_post_direct_write() invalidate_mapping_pages() invalidate_inode_pages2_range() -> finds dirty page! -> dio_warn_stale_pagecache() -> errseq_set(-EIO) This issue can be triggered through normal I/O paths, not just intentionally overlapping DIO writes from userspace. For example, generic/746 uses a loop device where multiple kworkers issue concurrent I/O to the backing file. Additionally, when block_size < folio_size, non-overlapping DIO writes that share a large folio can also trigger the race. Add inode_dio_wait() in ext4_buffered_write_iter() before ext4_write_checks() to drain all in-flight DIO. This ensures that all DIO clears existing pages before submitting IO (via kiocb_invalidate_pages()), all BIO waits for all DIO to complete (via inode_dio_wait()), and ext4_write_checks() observes the inode size after all completed DIO so that ext4_block_zero_eof() does not race with in-flight DIO, thus eliminating the race. Fixes: 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure") Suggested-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/d1adcf7c-c276-458d-9cac-68a4410f7626@gmail.com Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com> Link: https://patch.msgid.link/20260629113827.4074335-3-libaokun@linux.alibaba.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-04-17Merge tag 'ext4_for_linux-7.0-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: - Refactor code paths involved with partial block zero-out in prearation for converting ext4 to use iomap for buffered writes - Remove use of d_alloc() from ext4 in preparation for the deprecation of this interface - Replace some J_ASSERTS with a journal abort so we can avoid a kernel panic for a localized file system error - Simplify various code paths in mballoc, move_extent, and fast commit - Fix rare deadlock in jbd2_journal_cancel_revoke() that can be triggered by generic/013 when blocksize < pagesize - Fix memory leak when releasing an extended attribute when its value is stored in an ea_inode - Fix various potential kunit test bugs in fs/ext4/extents.c - Fix potential out-of-bounds access in check_xattr() with a corrupted file system - Make the jbd2_inode dirty range tracking safe for lockless reads - Avoid a WARN_ON when writeback files due to a corrupted file system; we already print an ext4 warning indicatign that data will be lost, so the WARN_ON is not necessary and doesn't add any new information * tag 'ext4_for_linux-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (37 commits) jbd2: fix deadlock in jbd2_journal_cancel_revoke() ext4: fix missing brelse() in ext4_xattr_inode_dec_ref_all() ext4: fix possible null-ptr-deref in mbt_kunit_exit() ext4: fix possible null-ptr-deref in extents_kunit_exit() ext4: fix the error handling process in extents_kunit_init). ext4: call deactivate_super() in extents_kunit_exit() ext4: fix miss unlock 'sb->s_umount' in extents_kunit_init() ext4: fix bounds check in check_xattrs() to prevent out-of-bounds access ext4: zero post-EOF partial block before appending write ext4: move pagecache_isize_extended() out of active handle ext4: remove ctime/mtime update from ext4_alloc_file_blocks() ext4: unify SYNC mode checks in fallocate paths ext4: ensure zeroed partial blocks are persisted in SYNC mode ext4: move zero partial block range functions out of active handle ext4: pass allocate range as loff_t to ext4_alloc_file_blocks() ext4: remove handle parameters from zero partial block functions ext4: move ordered data handling out of ext4_block_do_zero_range() ext4: rename ext4_block_zero_page_range() to ext4_block_zero_range() ext4: factor out journalled block zeroing range ext4: rename and extend ext4_block_truncate_page() ...
2026-04-09ext4: zero post-EOF partial block before appending writeZhang Yi
In cases of appending write beyond EOF, ext4_zero_partial_blocks() is called within ext4_*_write_end() to zero out the partial block beyond EOF. This prevents exposing stale data that might be written through mmap. However, supporting only the regular buffered write path is insufficient. It is also necessary to support the DAX path as well as the upcoming iomap buffered write path. Therefore, move this operation to ext4_write_checks(). In addition, this may introduce a race window in which a post-EOF buffered write can race with an mmap write after the old EOF block has been zeroed. As a result, the data in this block written by the buffer-write and the data written by the mmap-write may be mixed. However, this is safe because users should not rely on the result of the race condition. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20260327102939.1095257-14-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-04-05fs: remove unncessary pagevec.h includesTal Zussman
Remove unused pagevec.h includes from .c files. These were found with the following command: grep -rl '#include.*pagevec\.h' --include='*.c' | while read f; do grep -qE 'PAGEVEC_SIZE|folio_batch' "$f" || echo "$f" done There are probably more removal candidates in .h files, but those are more complex to analyze. Link: https://lkml.kernel.org/r/20260225-pagevec_cleanup-v2-2-716868cc2d11@columbia.edu Signed-off-by: Tal Zussman <tz2294@columbia.edu> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Zi Yan <ziy@nvidia.com> Acked-by: Chris Li <chrisl@kernel.org> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand (Arm) <david@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-02-18Merge tag 'mm-stable-2026-02-18-19-48' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull more MM updates from Andrew Morton: - "mm/vmscan: fix demotion targets checks in reclaim/demotion" fixes a couple of issues in the demotion code - pages were failed demotion and were finding themselves demoted into disallowed nodes (Bing Jiao) - "Remove XA_ZERO from error recovery of dup_mmap()" fixes a rare mapledtree race and performs a number of cleanups (Liam Howlett) - "mm: add bitmap VMA flag helpers and convert all mmap_prepare to use them" implements a lot of cleanups following on from the conversion of the VMA flags into a bitmap (Lorenzo Stoakes) - "support batch checking of references and unmapping for large folios" implements batching to greatly improve the performance of reclaiming clean file-backed large folios (Baolin Wang) - "selftests/mm: add memory failure selftests" does as claimed (Miaohe Lin) * tag 'mm-stable-2026-02-18-19-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (36 commits) mm/page_alloc: clear page->private in free_pages_prepare() selftests/mm: add memory failure dirty pagecache test selftests/mm: add memory failure clean pagecache test selftests/mm: add memory failure anonymous page test mm: rmap: support batched unmapping for file large folios arm64: mm: implement the architecture-specific clear_flush_young_ptes() arm64: mm: support batch clearing of the young flag for large folios arm64: mm: factor out the address and ptep alignment into a new helper mm: rmap: support batched checks of the references for large folios tools/testing/vma: add VMA userland tests for VMA flag functions tools/testing/vma: separate out vma_internal.h into logical headers tools/testing/vma: separate VMA userland tests into separate files mm: make vm_area_desc utilise vma_flags_t only mm: update all remaining mmap_prepare users to use vma_flags_t mm: update shmem_[kernel]_file_*() functions to use vma_flags_t mm: update secretmem to use VMA flags on mmap_prepare mm: update hugetlbfs to use VMA flags on mmap_prepare mm: add basic VMA flag operation helper functions tools: bitmap: add missing bitmap_[subset(), andnot()] mm: add mk_vma_flags() bitmap flag macro helper ...
2026-02-12mm: update all remaining mmap_prepare users to use vma_flags_tLorenzo Stoakes
We will be shortly removing the vm_flags_t field from vm_area_desc so we need to update all mmap_prepare users to only use the dessc->vma_flags field. This patch achieves that and makes all ancillary changes required to make this possible. This lays the groundwork for future work to eliminate the use of vm_flags_t in vm_area_desc altogether and more broadly throughout the kernel. While we're here, we take the opportunity to replace VM_REMAP_FLAGS with VMA_REMAP_FLAGS, the vma_flags_t equivalent. No functional changes intended. Link: https://lkml.kernel.org/r/fb1f55323799f09fe6a36865b31550c9ec67c225.1769097829.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: Damien Le Moal <dlemoal@kernel.org> [zonefs] Acked-by: "Darrick J. Wong" <djwong@kernel.org> Acked-by: Pedro Falcato <pfalcato@suse.de> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Yury Norov <ynorov@nvidia.com> Cc: Chris Mason <clm@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-02-12Merge tag 'ext4_for_linus-7.0-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "New features and improvements for the ext4 file system - Avoid unnecessary cache invalidation in the extent status cache (es_cache) when adding extents to be cached in the es_cache and we are not changing the extent tree - Add a sysfs parameter, err_report_sec, to control how frequently to log a warning message that file system inconsistency has been detected (Previously we logged the warning message every 24 hours) - Avoid unnecessary forced ordered writes when appending to a file when delayed allocation is enabled - Defer splitting unwritten extents to I/O completion to improve write performance of concurrent direct I/O writes to multiple files - Refactor and add kunit tests to the extent splitting and conversion code paths Various Bug Fixes: - Fix a panic when the debugging DOUBLE_CHECK macro is defined - Avoid using fast commit for rare and complex file system operations to make fast commit easier to reason about. This can also avoid some corner cases that could result in file system inconsistency if there is a crash between the fast commit before a subsequent full commit - Fix memory leaks in error paths - Fix a false positive reports caused when running stress tests using mixed huge-page workloads caused by a race between page migration and bitmap updates - Fix a potential recursion into file system reclaim when evicting an inode when fast commit is enabled - Fix a warning caused by a potential double decrement to the dirty clusters counter when executing FS_IOC_SHUTDOWN when running a stress test - Enable mballoc optimized scanning regardless whether the inode is using indirect blocks or extent trees to map blocks" * tag 'ext4_for_linus-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (45 commits) et4: allow zeroout when doing written to unwritten split ext4: refactor split and convert extents ext4: refactor zeroout path and handle all cases ext4: propagate flags to ext4_convert_unwritten_extents_endio() ext4: propagate flags to convert_initialized_extent() ext4: add extent status cache support to kunit tests ext4: kunit tests for higher level extent manipulation functions ext4: kunit tests for extent splitting and conversion ext4: use optimized mballoc scanning regardless of inode format ext4: always allocate blocks only from groups inode can use ext4: fix dirtyclusters double decrement on fs shutdown ext4: fast commit: make s_fc_lock reclaim-safe ext4: fix e4b bitmap inconsistency reports ext4: remove redundant NULL check after __GFP_NOFAIL ext4: remove EXT4_GET_BLOCKS_IO_CREATE_EXT ext4: simplify the mapping query logic in ext4_iomap_begin() ext4: remove unused unwritten parameter in ext4_dio_write_iter() ext4: remove useless ext4_iomap_overwrite_ops ext4: avoid starting handle when dio writing an unwritten extent ext4: don't split extent before submitting I/O ...
2026-01-19ext4: remove unused unwritten parameter in ext4_dio_write_iter()Zhang Yi
The parameter unwritten in ext4_dio_write_iter() is no longer needed, simply remove it. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/20260105014522.1937690-6-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-01-19ext4: remove useless ext4_iomap_overwrite_opsZhang Yi
ext4_iomap_overwrite_ops was introduced in commit 8cd115bdda17 ("ext4: Optimize ext4 DIO overwrites"), which can optimize pure overwrite performance by dropping the IOMAP_WRITE flag to only query the mapped mapping information. This avoids starting a new journal handle, thereby improving speed. Later, commit 9faac62d4013 ("ext4: optimize file overwrites") also optimized similar scenarios, but it performs the check later, examining the mappings status only when the actual block mapping is needed. Thus, it can handle the previous commit scenario. That means in the case of an overwrite scenario, the condition "offset + length <= i_size_read(inode)" in the write path must always be true. Therefore, it is acceptable to remove the ext4_iomap_overwrite_ops, which will also clarify the write and read paths of ext4_iomap_begin. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/20260105014522.1937690-5-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-01-19ext4: avoid starting handle when dio writing an unwritten extentZhang Yi
Since we have deferred the split of the unwritten extent until after I/O completion, it is not necessary to initiate the journal handle when submitting the I/O. This can improve the write performance of concurrent DIO for multiple files. The fio tests below show a ~25% performance improvement when wirting to unwritten files on my VM with a mem disk. [unwritten] direct=1 ioengine=psync numjobs=16 rw=write # write/randwrite bs=4K iodepth=1 directory=/mnt size=5G runtime=30s overwrite=0 norandommap=1 fallocate=native ramp_time=5s group_reporting=1 [w/o] w: IOPS=62.5k, BW=244MiB/s rw: IOPS=56.7k, BW=221MiB/s [w] w: IOPS=79.6k, BW=311MiB/s rw: IOPS=70.2k, BW=274MiB/s Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/20260105014522.1937690-4-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-01-19ext4: remove unnecessary zero-initialization via memsetpengdonglin
The d_path function does not require the caller to pre-zero the buffer. Signed-off-by: pengdonglin <pengdonglin@xiaomi.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Baokun Li <libaokun1@huawei.com> Link: https://patch.msgid.link/20251211123829.2777009-1-dolinux.peng@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2026-01-12ext4: add setlease file operationJeff Layton
Add the setlease file_operation to ext4_file_operations and ext4_dir_operations, pointing to generic_setlease. A future patch will change the default behavior to reject lease attempts with -EINVAL when there is no setlease file operation defined. Add generic_setlease to retain the ability to set leases on this filesystem. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260108-setlease-6-20-v1-6-ea4dec9b67fa@kernel.org Acked-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-26ext4: fix checks for orphan inodesJan Kara
When orphan file feature is enabled, inode can be tracked as orphan either in the standard orphan list or in the orphan file. The first can be tested by checking ei->i_orphan list head, the second is recorded by EXT4_STATE_ORPHAN_FILE inode state flag. There are several places where we want to check whether inode is tracked as orphan and only some of them properly check for both possibilities. Luckily the consequences are mostly minor, the worst that can happen is that we track an inode as orphan although we don't need to and e2fsck then complains (resulting in occasional ext4/307 xfstest failures). Fix the problem by introducing a helper for checking whether an inode is tracked as orphan and use it in appropriate places. Fixes: 4a79a98c7b19 ("ext4: Improve scalability of ext4 orphan file handling") Cc: stable@kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Message-ID: <20250925123038.20264-2-jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-31Merge tag 'mm-stable-2025-07-30-15-25' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...
2025-07-28Merge tag 'vfs-6.17-rc1.mmap_prepare' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull mmap_prepare updates from Christian Brauner: "Last cycle we introduce f_op->mmap_prepare() in c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file callback"). This is preferred to the existing f_op->mmap() hook as it does require a VMA to be established yet, thus allowing the mmap logic to invoke this hook far, far earlier, prior to inserting a VMA into the virtual address space, or performing any other heavy handed operations. This allows for much simpler unwinding on error, and for there to be a single attempt at merging a VMA rather than having to possibly reattempt a merge based on potentially altered VMA state. Far more importantly, it prevents inappropriate manipulation of incompletely initialised VMA state, which is something that has been the cause of bugs and complexity in the past. The intent is to gradually deprecate f_op->mmap, and in that vein this series coverts the majority of file systems to using f_op->mmap_prepare. Prerequisite steps are taken - firstly ensuring all checks for mmap capabilities use the file_has_valid_mmap_hooks() helper rather than directly checking for f_op->mmap (which is now not a valid check) and secondly updating daxdev_mapping_supported() to not require a VMA parameter to allow ext4 and xfs to be converted. Commit bb666b7c2707 ("mm: add mmap_prepare() compatibility layer for nested file systems") handles the nasty edge-case of nested file systems like overlayfs, which introduces a compatibility shim to allow f_op->mmap_prepare() to be invoked from an f_op->mmap() callback. This allows for nested filesystems to continue to function correctly with all file systems regardless of which callback is used. Once we finally convert all file systems, this shim can be removed. As a result, ecryptfs, fuse, and overlayfs remain unaltered so they can nest all other file systems. We additionally do not update resctl - as this requires an update to remap_pfn_range() (or an alternative to it) which we defer to a later series, equally we do not update cramfs which needs a mixed mapping insertion with the same issue, nor do we update procfs, hugetlbfs, syfs or kernfs all of which require VMAs for internal state and hooks. We shall return to all of these later" * tag 'vfs-6.17-rc1.mmap_prepare' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: doc: update porting, vfs documentation to describe mmap_prepare() fs: replace mmap hook with .mmap_prepare for simple mappings fs: convert most other generic_file_*mmap() users to .mmap_prepare() fs: convert simple use of generic_file_*_mmap() to .mmap_prepare() mm/filemap: introduce generic_file_*_mmap_prepare() helpers fs/xfs: transition from deprecated .mmap hook to .mmap_prepare fs/ext4: transition from deprecated .mmap hook to .mmap_prepare fs/dax: make it possible to check dev dax support without a VMA fs: consistently use can_mmap_file() helper mm/nommu: use file_has_valid_mmap_hooks() helper mm: rename call_mmap/mmap_prepare to vfs_mmap/mmap_prepare
2025-07-16ext4: support uncached buffered I/OTaotao Chen
Set FOP_DONTCACHE in ext4_file_operations to declare support for uncached buffered I/O. To handle this flag, update ext4_write_begin() and ext4_da_write_begin() to use write_begin_get_folio(), which encapsulates FGP_DONTCACHE logic based on iocb->ki_flags. Part of a series refactoring address_space_operations write_begin and write_end callbacks to use struct kiocb for passing write context and flags. Signed-off-by: Taotao Chen <chentaotao@didiglobal.com> Link: https://lore.kernel.org/20250716093559.217344-6-chentaotao@didiglobal.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-09mm: remove callers of pfn_t functionalityAlistair Popple
All PFN_* pfn_t flags have been removed. Therefore there is no longer a need for the pfn_t type and all uses can be replaced with normal pfns. Link: https://lkml.kernel.org/r/bbedfa576c9822f8032494efbe43544628698b1f.1750323463.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Balbir Singh <balbirs@nvidia.com> Cc: Björn Töpel <bjorn@kernel.org> Cc: Björn Töpel <bjorn@rivosinc.com> Cc: Chunyan Zhang <zhang.lyra@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Deepak Gupta <debug@rivosinc.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Inki Dae <m.szyprowski@samsung.com> Cc: John Groves <john@groves.net> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-06-17fs/ext4: transition from deprecated .mmap hook to .mmap_prepareLorenzo Stoakes
Since commit c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file callback"), the f_op->mmap() hook has been deprecated in favour of f_op->mmap_prepare(). This callback is invoked in the mmap() logic far earlier, so error handling can be performed more safely without complicated and bug-prone state unwinding required should an error arise. This hook also avoids passing a pointer to a not-yet-correctly-established VMA avoiding any issues with referencing this data structure. It rather provides a pointer to the new struct vm_area_desc descriptor type which contains all required state and allows easy setting of required parameters without any consideration needing to be paid to locking or reference counts. Note that nested filesystems like overlayfs are compatible with an .mmap_prepare() callback since commit bb666b7c2707 ("mm: add mmap_prepare() compatibility layer for nested file systems"). Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Link: https://lore.kernel.org/5abfe526032a6698fd1bcd074a74165cda7ea57c.1750099179.git.lorenzo.stoakes@oracle.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-17fs/dax: make it possible to check dev dax support without a VMALorenzo Stoakes
This is a prerequisite for adapting those filesystems to use the .mmap_prepare() hook for mmap()'ing which invoke this check as this hook does not have access to a VMA pointer. To effect this, change the signature of daxdev_mapping_supported() and update its callers (ext4 and xfs mmap()'ing hook code). Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Link: https://lore.kernel.org/b09de1e8544384074165d92d048e80058d971286.1750099179.git.lorenzo.stoakes@oracle.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-05-20ext4: Add multi-fsblock atomic write support with bigallocRitesh Harjani (IBM)
EXT4 supports bigalloc feature which allows the FS to work in size of clusters (group of blocks) rather than individual blocks. This patch adds atomic write support for bigalloc so that systems with bs = ps can also create FS using - mkfs.ext4 -F -O bigalloc -b 4096 -C 16384 <dev> With bigalloc ext4 can support multi-fsblock atomic writes. We will have to adjust ext4's atomic write unit max value to cluster size. This can then support atomic write of size anywhere between [blocksize, clustersize]. This patch adds the required changes to enable multi-fsblock atomic write support using bigalloc in the next patch. In this patch for block allocation: we first query the underlying region of the requested range by calling ext4_map_blocks() call. Here are the various cases which we then handle depending upon the underlying mapping type: 1. If the underlying region for the entire requested range is a mapped extent, then we don't call ext4_map_blocks() to allocate anything. We don't need to even start the jbd2 txn in this case. 2. For an append write case, we create a mapped extent. 3. If the underlying region is entirely a hole, then we create an unwritten extent for the requested range. 4. If the underlying region is a large unwritten extent, then we split the extent into 2 unwritten extent of required size. 5. If the underlying region has any type of mixed mapping, then we call ext4_map_blocks() in a loop to zero out the unwritten and the hole regions within the requested range. This then provide a single mapped extent type mapping for the requested range. Note: We invoke ext4_map_blocks() in a loop with the EXT4_GET_BLOCKS_ZERO flag only when the underlying extent mapping of the requested range is not entirely a hole, an unwritten extent, or a fully mapped extent. That is, if the underlying region contains a mix of hole(s), unwritten extent(s), and mapped extent(s), we use this loop to ensure that all the short mappings are zeroed out. This guarantees that the entire requested range becomes a single, uniformly mapped extent. It is ok to do so because we know this is being done on a bigalloc enabled filesystem where the block bitmap represents the entire cluster unit. Note having a single contiguous underlying region of type mapped, unwrittn or hole is not a problem. But the reason to avoid writing on top of mixed mapping region is because, atomic writes requires all or nothing should get written for the userspace pwritev2 request. So if at any point in time during the write if a crash or a sudden poweroff occurs, the region undergoing atomic write should read either complete old data or complete new data. But it should never have a mix of both old and new data. So, we first convert any mixed mapping region to a single contiguous mapped extent before any data gets written to it. This is because normally FS will only convert unwritten extents to written at the end of the write in ->end_io() call. And if we allow the writes over a mixed mapping and if a sudden power off happens in between, we will end up reading mix of new data (over mapped extents) and old data (over unwritten extents), because unwritten to written conversion never went through. So to avoid this and to avoid writes getting torned due to mixed mapping, we first allocate a single contiguous block mapping and then do the write. Acked-by: Darrick J. Wong <djwong@kernel.org> Co-developed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/c4965ac3407cbc773f0bc954d0966d9696f5038a.1747337952.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: factor out ext4_get_maxbytes()Zhang Yi
There are several locations that get the correct maxbytes value based on the inode's block type. It would be beneficial to extract a common helper function to make the code more clear. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Baokun Li <libaokun1@huawei.com> Link: https://patch.msgid.link/20250506012009.3896990-3-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
2025-03-27Merge tag 'ext4-for_linus-6.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Ext4 bug fixes and cleanups, including: - hardening against maliciously fuzzed file systems - backwards compatibility for the brief period when we attempted to ignore zero-width characters - avoid potentially BUG'ing if there is a file system corruption found during the file system unmount - fix free space reporting by statfs when project quotas are enabled and the free space is less than the remaining project quota Also improve performance when replaying a journal with a very large number of revoke records (applicable for Lustre volumes)" * tag 'ext4-for_linus-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (71 commits) ext4: fix OOB read when checking dotdot dir ext4: on a remount, only log the ro or r/w state when it has changed ext4: correct the error handle in ext4_fallocate() ext4: Make sb update interval tunable ext4: avoid journaling sb update on error if journal is destroying ext4: define ext4_journal_destroy wrapper ext4: hash: simplify kzalloc(n * 1, ...) to kzalloc(n, ...) jbd2: add a missing data flush during file and fs synchronization ext4: don't over-report free space or inodes in statvfs ext4: clear DISCARD flag if device does not support discard jbd2: remove jbd2_journal_unfile_buffer() ext4: reorder capability check last ext4: update the comment about mb_optimize_scan jbd2: fix off-by-one while erasing journal ext4: remove references to bh->b_page ext4: goto right label 'out_mmap_sem' in ext4_setattr() ext4: fix out-of-bound read in ext4_xattr_inode_dec_ref_all() ext4: introduce ITAIL helper jbd2: remove redundant function jbd2_journal_has_csum_v2or3_feature ext4: remove redundant function ext4_has_metadata_csum ...
2025-03-13Revert "ext4: add pre-content fsnotify hook for DAX faults"Amir Goldstein
This reverts commit bb480760ffc7018e21ee6f60241c2b99ff26ee0e. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250312073852.2123409-3-amir73il@gmail.com
2025-03-13ext4: add more ext4_emergency_state() checks around sb_rdonly()Baokun Li
Some functions check sb_rdonly() to make sure the file system isn't modified after it's read-only. Since we also don't want the file system modified if it's in an emergency state (shutdown or emergency_ro), we're adding additional ext4_emergency_state() checks where sb_rdonly() is checked. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250122114130.229709-5-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-13ext4: add ext4_emergency_state() helper functionBaokun Li
Since both SHUTDOWN and EMERGENCY_RO are emergency states of the ext4 file system, and they are checked in similar locations, we have added a helper function, ext4_emergency_state(), to determine whether the current file system is in one of these two emergency states. Then, replace calls to ext4_forced_shutdown() with ext4_emergency_state() in those functions that could potentially trigger write operations. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250122114130.229709-4-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-12-11ext4: add pre-content fsnotify hook for DAX faultsJan Kara
ext4 has its own handling for DAX faults. Add the pre-content fsnotify hook for this case. Signed-off-by: Jan Kara <jack@suse.cz>
2024-11-18Merge tag 'ext4_for_linus-6.13-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "A lot of miscellaneous ext4 bug fixes and cleanups this cycle, most notably in the journaling code, bufered I/O, and compiler warning cleanups" * tag 'ext4_for_linus-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (33 commits) jbd2: Fix comment describing journal_init_common() ext4: prevent an infinite loop in the lazyinit thread ext4: use struct_size() to improve ext4_htree_store_dirent() ext4: annotate struct fname with __counted_by() jbd2: avoid dozens of -Wflex-array-member-not-at-end warnings ext4: use str_yes_no() helper function ext4: prevent delalloc to nodelalloc on remount jbd2: make b_frozen_data allocation always succeed ext4: cleanup variable name in ext4_fc_del() ext4: use string choices helpers jbd2: remove the 'success' parameter from the jbd2_do_replay() function jbd2: remove useless 'block_error' variable jbd2: factor out jbd2_do_replay() jbd2: refactor JBD2_COMMIT_BLOCK process in do_one_pass() jbd2: unified release of buffer_head in do_one_pass() jbd2: remove redundant judgments for check v1 checksum ext4: use ERR_CAST to return an error-valued pointer mm: zero range of eof folio exposed by inode size extension ext4: partial zero eof block on unaligned inode size extension ext4: disambiguate the return value of ext4_dio_write_end_io() ...
2024-11-12ext4: disambiguate the return value of ext4_dio_write_end_io()Jinliang Zheng
The commit 91562895f803 ("ext4: properly sync file size update after O_SYNC direct IO") causes confusion about the meaning of the return value of ext4_dio_write_end_io(). Specifically, when the ext4_handle_inode_extension() operation succeeds, ext4_dio_write_end_io() directly returns count instead of 0. This does not cause a bug in the current kernel, but the semantics of the return value of the ext4_dio_write_end_io() function are wrong, which is likely to introduce bugs in the future code evolution. Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20240919082539.381626-1-alexjlzheng@tencent.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-11-05ext4: Do not fallback to buffered-io for DIO atomic writeRitesh Harjani (IBM)
atomic writes is currently only supported for single fsblock and only for direct-io. We should not return -ENOTBLK for atomic writes since we want the atomic write request to either complete fully or fail otherwise. Hence, we should never fallback to buffered-io in case of DIO atomic write requests. Let's also catch if this ever happens by adding some WARN_ON_ONCE before buffered-io handling for direct-io atomic writes. More details of the discussion [1]. While at it let's add an inline helper ext4_want_directio_fallback() which simplifies the logic checks and inherently fixes condition on when to return -ENOTBLK which otherwise was always returning true for any write or directio in ext4_iomap_end(). It was ok since ext4 only supports direct-io via iomap. [1]: https://lore.kernel.org/linux-xfs/cover.1729825985.git.ritesh.list@gmail.com/T/#m9dbecc11bed713ed0d7a486432c56b105b555f04 Suggested-by: Darrick J. Wong <djwong@kernel.org> # inline helper Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz>
2024-11-05ext4: Support setting FMODE_CAN_ATOMIC_WRITERitesh Harjani (IBM)
FS needs to add the fmode capability in order to support atomic writes during file open (refer kiocb_set_rw_flags()). Set this capability on a regular file if ext4 can do atomic write. Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz>
2024-11-05ext4: Check for atomic writes support in write iterRitesh Harjani (IBM)
Let's validate the given constraints for atomic write request. Otherwise it will fail with -EINVAL. Currently atomic write is only supported on DIO, so for buffered-io it will return -EOPNOTSUPP. Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz>
2024-10-30ext4: Call ext4_journal_stop(handle) only once in ext4_dio_write_iter()Markus Elfring
An ext4_journal_stop(handle) call was immediately used after a return value check for a ext4_orphan_add() call in this function implementation. Thus call such a function only once instead directly before the check. This issue was transformed by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/cf895072-43cf-412c-bced-8268498ad13e@web.de Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-09-03ext4: dax: keep orphan list before truncate overflow allocated blocksyangerkun
Any extending write for ext4 requires the inode to be placed on the orphan list before the actual write. In addition, the inode can be actually removed from the orphan list only after all writes are completed. Otherwise we'd leave allocated blocks beyond i_disksize if we could not copy all the data into allocated block and e2fsck would complain. Currently, direct IO and buffered IO comply with this logic(buffered IO will truncate all overflow allocated blocks that has not been written successfully, and direct IO will truncate all allocated blocks when error occurs). However, dax write break this since dax write will remove the inode from the orphan list by calling ext4_handle_inode_extension unconditionally during extending write. We add a argument to help determine does we do a fully write, and for the case not fully write, we leave the inode on the orphan list, and the latter ext4_inode_extension_cleanup will help us truncate the overflow allocated blocks, and then remove the inode from the orphan list. Signed-off-by: yangerkun <yangerkun@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20240829110222.126685-1-yangerkun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-08-26ext4: dax: fix overflowing extents beyond inode size when partially writingZhihao Cheng
The dax_iomap_rw() does two things in each iteration: map written blocks and copy user data to blocks. If the process is killed by user(See signal handling in dax_iomap_iter()), the copied data will be returned and added on inode size, which means that the length of written extents may exceed the inode size, then fsck will fail. An example is given as: dd if=/dev/urandom of=file bs=4M count=1 dax_iomap_rw iomap_iter // round 1 ext4_iomap_begin ext4_iomap_alloc // allocate 0~2M extents(written flag) dax_iomap_iter // copy 2M data iomap_iter // round 2 iomap_iter_advance iter->pos += iter->processed // iter->pos = 2M ext4_iomap_begin ext4_iomap_alloc // allocate 2~4M extents(written flag) dax_iomap_iter fatal_signal_pending done = iter->pos - iocb->ki_pos // done = 2M ext4_handle_inode_extension ext4_update_inode_size // inode size = 2M fsck reports: Inode 13, i_size is 2097152, should be 4194304. Fix? Fix the problem by truncating extents if the written length is smaller than expected. Fixes: 776722e85d3b ("ext4: DAX iomap write support") CC: stable@vger.kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=219136 Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com> Link: https://patch.msgid.link/20240809121532.2105494-1-chengzhihao@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-05-18Merge tag 'ext4_for_linus-6.10-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: - more folio conversion patches - add support for FS_IOC_GETFSSYSFSPATH - mballoc cleaups and add more kunit tests - sysfs cleanups and bug fixes - miscellaneous bug fixes and cleanups * tag 'ext4_for_linus-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (40 commits) ext4: fix error pointer dereference in ext4_mb_load_buddy_gfp() jbd2: add prefix 'jbd2' for 'shrink_type' jbd2: use shrink_type type instead of bool type for __jbd2_journal_clean_checkpoint_list() ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super() ext4: remove calls to to set/clear the folio error flag ext4: propagate errors from ext4_sb_bread() in ext4_xattr_block_cache_find() ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() jbd2: remove redundant assignement to variable err ext4: remove the redundant folio_wait_stable() ext4: fix potential unnitialized variable ext4: convert ac_buddy_page to ac_buddy_folio ext4: convert ac_bitmap_page to ac_bitmap_folio ext4: convert ext4_mb_init_cache() to take a folio ext4: convert bd_buddy_page to bd_buddy_folio ext4: convert bd_bitmap_page to bd_bitmap_folio ext4: open coding repeated check in next_linear_group ext4: use correct criteria name instead stale integer number in comment ext4: call ext4_mb_mark_free_simple to free continuous bits in found chunk ext4: add test_mb_mark_used_cost to estimate cost of mb_mark_used ext4: keep "prefetch_grp" and "nr" consistent ...
2024-05-02ext4: replace deprecated strncpy with alternativesJustin Stitt
strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. in file.c: s_last_mounted is marked as __nonstring meaning it does not need to be NUL-terminated. Let's instead use strtomem_pad() to copy bytes from the string source to the byte array destination -- while also ensuring to pad with zeroes. in ioctl.c: We can drop the memset and size argument in favor of using the new 2-argument version of strscpy_pad() -- which was introduced with Commit e6584c3964f2f ("string: Allow 2-argument strscpy()"). This guarantees NUL-termination and NUL-padding on the destination buffer -- which seems to be a requirement judging from this comment: | static int ext4_ioctl_getlabel(struct ext4_sb_info *sbi, char __user *user_label) | { | char label[EXT4_LABEL_MAX + 1]; | | /* | * EXT4_LABEL_MAX must always be smaller than FSLABEL_MAX because | * FSLABEL_MAX must include terminating null byte, while s_volume_name | * does not have to. | */ in super.c: s_first_error_func is marked as __nonstring meaning we can take the same approach as in file.c; just use strtomem_pad() Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20240321-strncpy-fs-ext4-file-c-v1-1-36a6a09fef0c@google.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-05-02ext4: set FMODE_CAN_ODIRECT instead of a dummy direct_IO methodChristoph Hellwig
Since commit a2ad63daa88b ("VFS: add FMODE_CAN_ODIRECT file flag") file systems can just set the FMODE_CAN_ODIRECT flag at open time instead of wiring up a dummy direct_IO method to indicate support for direct I/O. Signed-off-by: Christoph Hellwig <hch@lst.de> [RH: Rebased to upstream] Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/e5797bb597219a49043e53e4e90aa494b97dc328.1709215665.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-04-07fs: claw back a few FMODE_* bitsChristian Brauner
There's a bunch of flags that are purely based on what the file operations support while also never being conditionally set or unset. IOW, they're not subject to change for individual files. Imho, such flags don't need to live in f_mode they might as well live in the fops structs itself. And the fops struct already has that lonely mmap_supported_flags member. We might as well turn that into a generic fop_flags member and move a few flags from FMODE_* space into FOP_* space. That gets us four FMODE_* bits back and the ability for new static flags that are about file ops to not have to live in FMODE_* space but in their own FOP_* space. It's not the most beautiful thing ever but it gets the job done. Yes, there'll be an additional pointer chase but hopefully that won't matter for these flags. I suspect there's a few more we can move into there and that we can also redirect a bunch of new flag suggestions that follow this pattern into the fop_flags field instead of f_mode. Link: https://lore.kernel.org/r/20240328-gewendet-spargel-aa60a030ef74@brauner Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-01-18ext4: remove unnecessary parameter "needed" in ext4_discard_preallocationsKemeng Shi
The "needed" controls the number of ext4_prealloc_space to discard in ext4_discard_preallocations. Function ext4_discard_preallocations is supposed to discard all non-used preallocated blocks when "needed" is 0 and now ext4_discard_preallocations is always called with "needed" = 0. Remove unnecessary parameter "needed" and remove all non-used preallocated spaces in ext4_discard_preallocations to simplify the code. Note: If count of non-used preallocated spaces could be more than UINT_MAX, there was a memory leak as some non-used preallocated spaces are left ununsed and this commit will fix it. Otherwise, there is no behavior change. Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20240105092102.496631-9-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2023-11-30ext4: fix warning in ext4_dio_write_end_io()Jan Kara
The syzbot has reported that it can hit the warning in ext4_dio_write_end_io() because i_size < i_disksize. Indeed the reproducer creates a race between DIO IO completion and truncate expanding the file and thus ext4_dio_write_end_io() sees an inconsistent inode state where i_disksize is already updated but i_size is not updated yet. Since we are careful when setting up DIO write and consider it extending (and thus performing the IO synchronously with i_rwsem held exclusively) whenever it goes past either of i_size or i_disksize, we can use the same test during IO completion without risking entering ext4_handle_inode_extension() without i_rwsem held. This way we make it obvious both i_size and i_disksize are large enough when we report DIO completion without relying on unreliable WARN_ON. Reported-by: <syzbot+47479b71cdfc78f56d30@syzkaller.appspotmail.com> Fixes: 91562895f803 ("ext4: properly sync file size update after O_SYNC direct IO") Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20231130095653.22679-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2023-10-31ext4: properly sync file size update after O_SYNC direct IOJan Kara
Gao Xiang has reported that on ext4 O_SYNC direct IO does not properly sync file size update and thus if we crash at unfortunate moment, the file can have smaller size although O_SYNC IO has reported successful completion. The problem happens because update of on-disk inode size is handled in ext4_dio_write_iter() *after* iomap_dio_rw() (and thus dio_complete() in particular) has returned and generic_file_sync() gets called by dio_complete(). Fix the problem by handling on-disk inode size update directly in our ->end_io completion handler. References: https://lore.kernel.org/all/02d18236-26ef-09b0-90ad-030c4fe3ee20@linux.alibaba.com Reported-by: Gao Xiang <hsiangkao@linux.alibaba.com> CC: stable@vger.kernel.org Fixes: 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure") Signed-off-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20231013121350.26872-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2023-10-31ext4: fix racy may inline data check in dio writeBrian Foster
syzbot reports that the following warning from ext4_iomap_begin() triggers as of the commit referenced below: if (WARN_ON_ONCE(ext4_has_inline_data(inode))) return -ERANGE; This occurs during a dio write, which is never expected to encounter an inode with inline data. To enforce this behavior, ext4_dio_write_iter() checks the current inline state of the inode and clears the MAY_INLINE_DATA state flag to either fall back to buffered writes, or enforce that any other writers in progress on the inode are not allowed to create inline data. The problem is that the check for existing inline data and the state flag can span a lock cycle. For example, if the ilock is originally locked shared and subsequently upgraded to exclusive, another writer may have reacquired the lock and created inline data before the dio write task acquires the lock and proceeds. The commit referenced below loosens the lock requirements to allow some forms of unaligned dio writes to occur under shared lock, but AFAICT the inline data check was technically already racy for any dio write that would have involved a lock cycle. Regardless, lift clearing of the state bit to the same lock critical section that checks for preexisting inline data on the inode to close the race. Cc: stable@kernel.org Reported-by: syzbot+307da6ca5cb0d01d581a@syzkaller.appspotmail.com Fixes: 310ee0902b8d ("ext4: allow concurrent unaligned dio overwrites") Signed-off-by: Brian Foster <bfoster@redhat.com> Link: https://lore.kernel.org/r/20231002185020.531537-1-bfoster@redhat.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2023-08-31Merge tag 'ext4_for_linus-6.6-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Many ext4 and jbd2 cleanups and bug fixes: - Cleanups in the ext4 remount code when going to and from read-only - Cleanups in ext4's multiblock allocator - Cleanups in the jbd2 setup/mounting code paths - Performance improvements when appending to a delayed allocation file - Miscellaneous syzbot and other bug fixes" * tag 'ext4_for_linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (60 commits) ext4: fix slab-use-after-free in ext4_es_insert_extent() libfs: remove redundant checks of s_encoding ext4: remove redundant checks of s_encoding ext4: reject casefold inode flag without casefold feature ext4: use LIST_HEAD() to initialize the list_head in mballoc.c ext4: do not mark inode dirty every time when appending using delalloc ext4: rename s_error_work to s_sb_upd_work ext4: add periodic superblock update check ext4: drop dio overwrite only flag and associated warning ext4: add correct group descriptors and reserved GDT blocks to system zone ext4: remove unused function declaration ext4: mballoc: avoid garbage value from err ext4: use sbi instead of EXT4_SB(sb) in ext4_mb_new_blocks_simple() ext4: change the type of blocksize in ext4_mb_init_cache() ext4: fix unttached inode after power cut with orphan file feature enabled jbd2: correct the end of the journal recovery scan range ext4: ext4_get_{dev}_journal return proper error value ext4: cleanup ext4_get_dev_journal() and ext4_get_journal() jbd2: jbd2_journal_init_{dev,inode} return proper error return value jbd2: drop useless error tag in jbd2_journal_wipe() ...