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2025-07-13ext4: enhance tracepoints during the folios writebackZhang Yi
After mpage_map_and_submit_extent() supports restarting handle if credits are insufficient during allocating blocks, it is more likely to exit the current mapping iteration and continue to process the current processing partially mapped folio again. The existing tracepoints are not sufficient to track this situation, so enhance the tracepoints to track the writeback position and the return value before and after submitting the folios. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250707140814.542883-7-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-13ext4: restart handle if credits are insufficient during allocating blocksZhang Yi
After large folios are supported on ext4, writing back a sufficiently large and discontinuous folio may consume a significant number of journal credits, placing considerable strain on the journal. For example, in a 20GB filesystem with 1K block size and 1MB journal size, writing back a 2MB folio could require thousands of credits in the worst-case scenario (when each block is discontinuous and distributed across different block groups), potentially exceeding the journal size. This issue can also occur in ext4_write_begin() and ext4_page_mkwrite() when delalloc is not enabled. Fix this by ensuring that there are sufficient journal credits before allocating an extent in mpage_map_one_extent() and ext4_block_write_begin(). If there are not enough credits, return -EAGAIN, exit the current mapping loop, restart a new handle and a new transaction, and allocating blocks on this folio again in the next iteration. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250707140814.542883-6-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-13ext4: refactor the block allocation process of ext4_page_mkwrite()Zhang Yi
The block allocation process and error handling in ext4_page_mkwrite() is complex now. Refactor it by introducing a new helper function, ext4_block_page_mkwrite(). It will call ext4_block_write_begin() to allocate blocks instead of directly calling block_page_mkwrite(). Preparing to implement retry logic in a subsequent patch to address situations where the reserved journal credits are insufficient. Additionally, this modification will help prevent potential deadlocks that may occur when waiting for folio writeback while holding the transaction handle. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250707140814.542883-5-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-13ext4: fix stale data if it bail out of the extents mapping loopZhang Yi
During the process of writing back folios, if mpage_map_and_submit_extent() exits the extent mapping loop due to an ENOSPC or ENOMEM error, it may result in stale data or filesystem inconsistency in environments where the block size is smaller than the folio size. When mapping a discontinuous folio in mpage_map_and_submit_extent(), some buffers may have already be mapped. If we exit the mapping loop prematurely, the folio data within the mapped range will not be written back, and the file's disk size will not be updated. Once the transaction that includes this range of extents is committed, this can lead to stale data or filesystem inconsistency. Fix this by submitting the current processing partially mapped folio. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250707140814.542883-4-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-13ext4: move the calculation of wbc->nr_to_write to mpage_folio_done()Zhang Yi
mpage_folio_done() should be a more appropriate place than mpage_submit_folio() for updating the wbc->nr_to_write after we have submitted a fully mapped folio. Preparing to make mpage_submit_folio() allows to submit partially mapped folio that is still under processing. 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/20250707140814.542883-3-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-13ext4: process folios writeback in bytesZhang Yi
Since ext4 supports large folios, processing writebacks in pages is no longer appropriate, it can be modified to process writebacks in bytes. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250707140814.542883-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-12ext4: remove unused EXT_STATS macro from ext4_extents.hBaolin Liu
The EXT_STATS macro in fs/ext4/ext4_extents.h has been defined but never used in the codebase since its introduction. This patch removes it. Analysis: 1. No references found in fs/ext4/ or other kernel code. 2. No impact on compilation or functionality. 3. Git history shows it was never utilized. Signed-off-by: Baolin Liu <liubaolin@kylinos.cn> Reviewed-by: Baokun Li <libaokun1@huawei.com> Link: https://patch.msgid.link/20250527053805.1550912-1-liubaolin12138@163.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-11ext4: remove unnecessary duplicate check in ext4_map_blocks()Dan Carpenter
The previous lines ensure that EXT4_GET_BLOCKS_QUERY_LAST_IN_LEAF is set so remove this duplicate check. Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/aDCdjUhpzxB64vkD@stanley.mountain Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-10ext4: remove duplicate check for EXT4_FC_REPLAYJinliang Zheng
EXT4_FC_REPLAY will be checked in ext4_es_lookup_extent(). If it is set, ext4_es_lookup_extent() will return 0. Remove the repeated check for EXT4_FC_REPLAY in ext4_map_blocks() to simplify the code. Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250429111722.294975-1-alexjlzheng@tencent.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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>
2025-07-04tree-wide: s/struct fileattr/struct file_kattr/gChristian Brauner
Now that we expose struct file_attr as our uapi struct rename all the internal struct to struct file_kattr to clearly communicate that it is a kernel internal struct. This is similar to struct mount_{k}attr and others. Link: https://lore.kernel.org/20250703-restlaufzeit-baurecht-9ed44552b481@brauner Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-24fs: Remove three arguments from block_write_end()Matthew Wilcox (Oracle)
block_write_end() looks like it can be used as a ->write_end() implementation. However, it can't as it does not unlock nor put the folio. Since it does not use the 'file', 'mapping' nor 'fsdata' arguments, remove them. Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Link: https://lore.kernel.org/20250624132130.1590285-1-willy@infradead.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-06-23ext4: add FALLOC_FL_WRITE_ZEROES supportZhang Yi
Add support for FALLOC_FL_WRITE_ZEROES if the underlying device enable the unmap write zeroes operation. This first allocates blocks as unwritten, then issues a zero command outside of the running journal handle, and finally converts them to a written state. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://lore.kernel.org/20250619111806.3546162-10-yi.zhang@huaweicloud.com Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com> Signed-off-by: Christian Brauner <brauner@kernel.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>
2025-06-08treewide, timers: Rename from_timer() to timer_container_of()Ingo Molnar
Move this API to the canonical timer_*() namespace. [ tglx: Redone against pre rc1 ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com
2025-05-28Merge tag 'ext4_for_linus-6.16-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "New ext4 features and performance improvements: - Fast commit performance improvements - Multi-fsblock atomic write support for bigalloc file systems - Large folio support for regular files This last can result in really stupendous performance for the right workloads. For example, see [1] where the Kernel Test Robot reported over 37% improvement on a large sequential I/O workload. There are also the usual bug fixes and cleanups. Of note are cleanups of the extent status tree to fix potential races that could result in the extent status tree getting corrupted under heavy simultaneous allocation and deallocation to a single file" Link: https://lore.kernel.org/all/202505161418.ec0d753f-lkp@intel.com/ [1] * tag 'ext4_for_linus-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (52 commits) ext4: Add a WARN_ON_ONCE for querying LAST_IN_LEAF instead ext4: Simplify flags in ext4_map_query_blocks() ext4: Rename and document EXT4_EX_FILTER to EXT4_EX_QUERY_FILTER ext4: Simplify last in leaf check in ext4_map_query_blocks ext4: Unwritten to written conversion requires EXT4_EX_NOCACHE ext4: only dirty folios when data journaling regular files ext4: Add atomic block write documentation ext4: Enable support for ext4 multi-fsblock atomic write using bigalloc ext4: Add multi-fsblock atomic write support with bigalloc ext4: Add support for EXT4_GET_BLOCKS_QUERY_LEAF_BLOCKS ext4: Make ext4_meta_trans_blocks() non-static for later use ext4: Check if inode uses extents in ext4_inode_can_atomic_write() ext4: Document an edge case for overwrites jbd2: remove journal_t argument from jbd2_superblock_csum() jbd2: remove journal_t argument from jbd2_chksum() ext4: remove sb argument from ext4_superblock_csum() ext4: remove sbi argument from ext4_chksum() ext4: enable large folio for regular file ext4: make online defragmentation support large folios ext4: make the writeback path support large folios ...
2025-05-26Merge tag 'xfs-merge-6.16' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds
Pull xfs updates from Carlos Maiolino: - Atomic writes for XFS - Remove experimental warnings for pNFS, scrub and parent pointers * tag 'xfs-merge-6.16' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (26 commits) xfs: add inode to zone caching for data placement xfs: free the item in xfs_mru_cache_insert on failure xfs: remove the EXPERIMENTAL warning for pNFS xfs: remove some EXPERIMENTAL warnings xfs: Remove deprecated xfs_bufd sysctl parameters xfs: stop using set_blocksize xfs: allow sysadmins to specify a maximum atomic write limit at mount time xfs: update atomic write limits xfs: add xfs_calc_atomic_write_unit_max() xfs: add xfs_file_dio_write_atomic() xfs: commit CoW-based atomic writes atomically xfs: add large atomic writes checks in xfs_direct_write_iomap_begin() xfs: add xfs_atomic_write_cow_iomap_begin() xfs: refine atomic write size check in xfs_file_write_iter() xfs: refactor xfs_reflink_end_cow_extent() xfs: allow block allocator to take an alignment hint xfs: ignore HW which cannot atomic write a single block xfs: add helpers to compute transaction reservation for finishing intent items xfs: add helpers to compute log item overhead xfs: separate out setting buftarg atomic writes limits ...
2025-05-20ext4: Add a WARN_ON_ONCE for querying LAST_IN_LEAF insteadRitesh Harjani (IBM)
We added the documentation in ext4_map_blocks() for usage of EXT4_GET_BLOCKS_QUERY_LAST_IN_LEAF flag. But It's better to add a WARN_ON_ONCE in case if anyone tries using this flag with CREATE to avoid a random issue later. Since depth can change with CREATE and it needs to be re-calculated before using it in there. Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/ee6e82a224c50b432df9ce1ce3333c50182d8473.1747677758.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: Simplify flags in ext4_map_query_blocks()Ritesh Harjani (IBM)
Now that we have EXT4_EX_QUERY_FILTER mask, let's use that to simplify the filtering of flags for passing to ext4_ext_map_blocks() in ext4_map_query_blocks() function. This allows us to kill the query_flags local variable which is not needed anymore. Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/4ae735e83e6f43341e53e2d289e59156a8360134.1747677758.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: Rename and document EXT4_EX_FILTER to EXT4_EX_QUERY_FILTERRitesh Harjani (IBM)
Rename EXT4_EX_FILTER to EXT4_EX_QUERY_FILTER to better describe its purpose as a filter mask used specifically in ext4_map_query_blocks(). Add a comment explaining that this macro is used to filter flags needed when querying the on-disk extent tree. We will later use EXT4_EX_QUERY_FILTER mask to add another EXT4_GET_BLOCKS_QUERY needed to lookup in on-disk extent tree. Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/51f05d0ba286372eb8693af95bd4b10194b53141.1747677758.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: Simplify last in leaf check in ext4_map_query_blocksRitesh Harjani (IBM)
This simplifies the check for last in leaf in ext4_map_query_blocks() and fixes this cocci warning. cocci warnings: (new ones prefixed by >>) >> fs/ext4/inode.c:573:49-51: WARNING !A || A && B is equivalent to !A || B Fixes: 5bb12b1837c0 ("ext4: Add support for EXT4_GET_BLOCKS_QUERY_LEAF_BLOCKS") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202505191524.auftmOwK-lkp@intel.com/ Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/5fd5c806218c83f603c578c95997cf7f6da29d74.1747677758.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: Unwritten to written conversion requires EXT4_EX_NOCACHERitesh Harjani (IBM)
This fixes the atomic write patch series after it was rebased on top of extent status cache cleanup series i.e. 'commit 402e38e6b71f57 ("ext4: prevent stale extent cache entries caused by concurrent I/O writeback")' After the above series, EXT4_GET_BLOCKS_IO_CONVERT_EXT flag which has EXT4_GET_BLOCKS_IO_SUBMIT flag set, requires that the io submit context of any kind should pass EXT4_EX_NOCACHE to avoid caching unncecessary extents in the extent status cache. This patch fixes that by adding the EXT4_EX_NOCACHE flag in ext4_convert_unwritten_extents_atomic() for unwritten to written conversion calls to ext4_map_blocks(). Fixes: b86629c2b299 ("ext4: Add multi-fsblock atomic write support with bigalloc") Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/ea0ad9378ff6d31d73f4e53f87548e3a20817689.1747677758.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: only dirty folios when data journaling regular filesBrian Foster
fstest generic/388 occasionally reproduces a crash that looks as follows: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: <TASK> ext4_block_zero_page_range+0x30c/0x380 [ext4] ext4_truncate+0x436/0x440 [ext4] ext4_process_orphan+0x5d/0x110 [ext4] ext4_orphan_cleanup+0x124/0x4f0 [ext4] ext4_fill_super+0x262d/0x3110 [ext4] get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x26/0xd0 vfs_cmd_create+0x59/0xe0 __do_sys_fsconfig+0x4ed/0x6b0 do_syscall_64+0x82/0x170 ... This occurs when processing a symlink inode from the orphan list. The partial block zeroing code in the truncate path calls ext4_dirty_journalled_data() -> folio_mark_dirty(). The latter calls mapping->a_ops->dirty_folio(), but symlink inodes are not assigned an a_ops vector in ext4, hence the crash. To avoid this problem, update the ext4_dirty_journalled_data() helper to only mark the folio dirty on regular files (for which a_ops is assigned). This also matches the journaling logic in the ext4_symlink() creation path, where ext4_handle_dirty_metadata() is called directly. Fixes: d84c9ebdac1e ("ext4: Mark pages with journalled data dirty") Signed-off-by: Brian Foster <bfoster@redhat.com> Link: https://patch.msgid.link/20250516173800.175577-1-bfoster@redhat.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Cc: stable@kernel.org
2025-05-20ext4: Enable support for ext4 multi-fsblock atomic write using bigallocRitesh Harjani (IBM)
Last couple of patches added the needed support for multi-fsblock atomic writes using bigalloc. This patch ensures that filesystem advertizes the needed atomic write unit min and max values for enabling multi-fsblock atomic write support with bigalloc. 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/5e45d7ed24499024b9079436ba6698dae5298e29.1747337952.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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: Add support for EXT4_GET_BLOCKS_QUERY_LEAF_BLOCKSRitesh Harjani (IBM)
There can be a case where there are contiguous extents on the adjacent leaf nodes of on-disk extent trees. So when someone tries to write to this contiguous range, ext4_map_blocks() call will split by returning 1 extent at a time if this is not already cached in extent_status tree cache (where if these extents when cached can get merged since they are contiguous). This is fine for a normal write however in case of atomic writes, it can't afford to break the write into two. Now this is also something that will only happen in the slow write case where we call ext4_map_blocks() for each of these extents spread across different leaf nodes. However, there is no guarantee that these extent status cache cannot be reclaimed before the last call to ext4_map_blocks() in ext4_map_blocks_atomic_write_slow(). Hence this patch adds support of EXT4_GET_BLOCKS_QUERY_LEAF_BLOCKS. This flag checks if the requested range can be fully found in extent status cache and return. If not, it looks up in on-disk extent tree via ext4_map_query_blocks(). If the found extent is the last entry in the leaf node, then it goes and queries the next lblk to see if there is an adjacent contiguous extent in the adjacent leaf node of the on-disk extent tree. Even though there can be a case where there are multiple adjacent extent entries spread across multiple leaf nodes. But we only read an adjacent leaf block i.e. in total of 2 extent entries spread across 2 leaf nodes. The reason for this is that we are mostly only going to support atomic writes with upto 64KB or maybe max upto 1MB of atomic write support. 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/6bb563e661f5fbd80e266a9e6ce6e29178f555f6.1747337952.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: Make ext4_meta_trans_blocks() non-static for later useRitesh Harjani (IBM)
Let's make ext4_meta_trans_blocks() non-static for use in later functions during ->end_io conversion for atomic writes. We will need this function to estimate journal credits for a special case. Instead of adding another wrapper around it, let's make this non-static. Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Acked-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/23ce80d4286f792831ce99d13558182ee228fedb.1747337952.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: Check if inode uses extents in ext4_inode_can_atomic_write()Ritesh Harjani (IBM)
EXT4 only supports doing atomic write on inodes which uses extents, so add a check in ext4_inode_can_atomic_write() which gets called during open. Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Acked-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/86bb502c979398a736ab371d8f35f6866a477f6c.1747337952.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: Document an edge case for overwritesRitesh Harjani (IBM)
ext4_iomap_overwrite_begin() clears the flag for IOMAP_WRITE before calling ext4_iomap_begin(). Document this above ext4_map_blocks() call as it is easy to miss it when focusing on write paths alone. Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Acked-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/fd50ba05440042dff77d555e463a620a79f8d0e9.1747337952.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: remove sb argument from ext4_superblock_csum()Eric Biggers
Since ext4_superblock_csum() no longer uses its sb argument, remove it. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Baokun Li <libaokun1@huawei.com> Link: https://patch.msgid.link/20250513053809.699974-3-ebiggers@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: remove sbi argument from ext4_chksum()Eric Biggers
Since ext4_chksum() no longer uses its sbi argument, remove it. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Baokun Li <libaokun1@huawei.com> Link: https://patch.msgid.link/20250513053809.699974-2-ebiggers@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: enable large folio for regular fileZhang Yi
Besides fsverity, fscrypt, and the data=journal mode, ext4 now supports large folios for regular files. Enable this feature by default. However, since we cannot change the folio order limitation of mappings on active inodes, setting the journal=data mode via ioctl on an active inode will not take immediate effect in non-delalloc mode. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-9-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: make online defragmentation support large foliosZhang Yi
move_extent_per_page() currently assumes that each folio is the size of PAGE_SIZE and only copies data for one page. ext4_move_extents() should call move_extent_per_page() for each page. To support larger folios, simply modify the calculations for the block start and end offsets within the folio based on the provided range of 'data_offset_in_page' and 'block_len_in_page'. This function will continue to handle PAGE_SIZE of data at a time and will not convert this function to manage an entire folio. Additionally, we use the source folio to copy data, so it doesn't matter if the source and dest folios are different in size. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-8-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: make the writeback path support large foliosZhang Yi
In mpage_map_and_submit_buffers(), the 'lblk' is now aligned to PAGE_SIZE. Convert it to be aligned to folio size. Additionally, modify the wbc->nr_to_write update to reduce the number of pages in a single folio, ensuring that the entire writeback path can support large folios. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-7-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: correct the journal credits calculations of allocating blocksZhang Yi
The journal credits calculation in ext4_ext_index_trans_blocks() is currently inadequate. It only multiplies the depth of the extents tree and doesn't account for the blocks that may be required for adding the leaf extents themselves. After enabling large folios, we can easily run out of handle credits, triggering a warning in jbd2_journal_dirty_metadata() on filesystems with a 1KB block size. This occurs because we may need more extents when iterating through each large folio in ext4_do_writepages()->mpage_map_and_submit_extent(). Therefore, we should modify ext4_ext_index_trans_blocks() to include a count of the leaf extents in the worst case as well. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-6-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4/jbd2: convert jbd2_journal_blocks_per_page() to support large folioZhang Yi
jbd2_journal_blocks_per_page() returns the number of blocks in a single page. Rename it to jbd2_journal_blocks_per_folio() and make it returns the number of blocks in the largest folio, preparing for the calculation of journal credits blocks when allocating blocks within a large folio in the writeback path. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-5-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: make __ext4_block_zero_page_range() support large folioZhang Yi
The partial block zero range helper __ext4_block_zero_page_range() currently only supports folios of PAGE_SIZE in size. The calculations for the start block and the offset within a folio for the given range are incorrect. Modify the implementation to use offset_in_folio() instead of directly masking PAGE_SIZE - 1, which will be able to support for large folios. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-4-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: make regular file's buffered write path support large foliosZhang Yi
The current buffered write path in ext4 can only allocate and handle folios of PAGE_SIZE size. To support larger folios, modify ext4_da_write_begin() and ext4_write_begin() to allocate higher-order folios, and trim the write length if it exceeds the folio size. Additionally, in ext4_da_do_write_end(), use offset_in_folio() instead of PAGE_SIZE. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-3-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: make ext4_mpage_readpages() support large foliosZhang Yi
ext4_mpage_readpages() currently assumes that each folio is the size of PAGE_SIZE. Modify it to atomically calculate the number of blocks per folio and iterate through the blocks in each folio, which would allow for support of larger folios. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250512063319.3539411-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: ensure i_size is smaller than maxbytesZhang Yi
The inode i_size cannot be larger than maxbytes, check it while loading inode from the disk. 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/20250506012009.3896990-4-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
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
2025-05-20ext4: fix incorrect punch max_endZhang Yi
For the extents based inodes, the maxbytes should be sb->s_maxbytes instead of sbi->s_bitmap_maxbytes. Additionally, for the calculation of max_end, the -sb->s_blocksize operation is necessary only for indirect-block based inodes. Correct the maxbytes and max_end value to correct the behavior of punch hole. Fixes: 2da376228a24 ("ext4: limit length to bitmap_maxbytes - blocksize in punch_hole") 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/20250506012009.3896990-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
2025-05-20ext4: fix out of bounds punch offsetZhang Yi
Punching a hole with a start offset that exceeds max_end is not permitted and will result in a negative length in the truncate_inode_partial_folio() function while truncating the page cache, potentially leading to undesirable consequences. A simple reproducer: truncate -s 9895604649994 /mnt/foo xfs_io -c "pwrite 8796093022208 4096" /mnt/foo xfs_io -c "fpunch 8796093022213 25769803777" /mnt/foo kernel BUG at include/linux/highmem.h:275! Oops: invalid opcode: 0000 [#1] SMP PTI CPU: 3 UID: 0 PID: 710 Comm: xfs_io Not tainted 6.15.0-rc3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014 RIP: 0010:zero_user_segments.constprop.0+0xd7/0x110 RSP: 0018:ffffc90001cf3b38 EFLAGS: 00010287 RAX: 0000000000000005 RBX: ffffea0001485e40 RCX: 0000000000001000 RDX: 000000000040b000 RSI: 0000000000000005 RDI: 000000000040b000 RBP: 000000000040affb R08: ffff888000000000 R09: ffffea0000000000 R10: 0000000000000003 R11: 00000000fffc7fc5 R12: 0000000000000005 R13: 000000000040affb R14: ffffea0001485e40 R15: ffff888031cd3000 FS: 00007f4f63d0b780(0000) GS:ffff8880d337d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000001ae0b038 CR3: 00000000536aa000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> truncate_inode_partial_folio+0x3dd/0x620 truncate_inode_pages_range+0x226/0x720 ? bdev_getblk+0x52/0x3e0 ? ext4_get_group_desc+0x78/0x150 ? crc32c_arch+0xfd/0x180 ? __ext4_get_inode_loc+0x18c/0x840 ? ext4_inode_csum+0x117/0x160 ? jbd2_journal_dirty_metadata+0x61/0x390 ? __ext4_handle_dirty_metadata+0xa0/0x2b0 ? kmem_cache_free+0x90/0x5a0 ? jbd2_journal_stop+0x1d5/0x550 ? __ext4_journal_stop+0x49/0x100 truncate_pagecache_range+0x50/0x80 ext4_truncate_page_cache_block_range+0x57/0x3a0 ext4_punch_hole+0x1fe/0x670 ext4_fallocate+0x792/0x17d0 ? __count_memcg_events+0x175/0x2a0 vfs_fallocate+0x121/0x560 ksys_fallocate+0x51/0xc0 __x64_sys_fallocate+0x24/0x40 x64_sys_call+0x18d2/0x4170 do_syscall_64+0xa7/0x220 entry_SYSCALL_64_after_hwframe+0x76/0x7e Fix this by filtering out cases where the punching start offset exceeds max_end. Fixes: 982bf37da09d ("ext4: refactor ext4_punch_hole()") Reported-by: Liebes Wang <wanghaichi0403@gmail.com> Closes: https://lore.kernel.org/linux-ext4/ac3a58f6-e686-488b-a9ee-fc041024e43d@huawei.com/ Tested-by: Liebes Wang <wanghaichi0403@gmail.com> 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/20250506012009.3896990-1-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
2025-05-20ext4: use writeback_iter in ext4_journalled_submit_inode_data_buffersChristoph Hellwig
Use writeback_iter directly instead of write_cache_pages for a nicer code structure and less indirect calls. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250505091604.3449879-1-hch@lst.de Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-20ext4: fix calculation of credits for extent tree modificationJan Kara
Luis and David are reporting that after running generic/750 test for 90+ hours on 2k ext4 filesystem, they are able to trigger a warning in jbd2_journal_dirty_metadata() complaining that there are not enough credits in the running transaction started in ext4_do_writepages(). Indeed the code in ext4_do_writepages() is racy and the extent tree can change between the time we compute credits necessary for extent tree computation and the time we actually modify the extent tree. Thus it may happen that the number of credits actually needed is higher. Modify ext4_ext_index_trans_blocks() to count with the worst case of maximum tree depth. This can reduce the possible number of writers that can operate in the system in parallel (because the credit estimates now won't fit in one transaction) but for reasonably sized journals this shouldn't really be an issue. So just go with a safe and simple fix. Link: https://lore.kernel.org/all/20250415013641.f2ppw6wov4kn4wq2@offworld Reported-by: Davidlohr Bueso <dave@stgolabs.net> Reported-by: Luis Chamberlain <mcgrof@kernel.org> Tested-by: kdevops@lists.linux.dev Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250429175535.23125-2-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
2025-05-16ext4: avoid -Wformat-security warningArnd Bergmann
check_igot_inode() prints a variable string, which causes a harmless warning with 'make W=1': fs/ext4/inode.c:4763:45: error: format string is not a string literal (potentially insecure) [-Werror,-Wformat-security] 4763 | ext4_error_inode(inode, function, line, 0, err_str); Use a trivial "%s" format string instead. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250423164354.2780635-1-arnd@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-15ext4: clairfy the rules for modifying extentsZhang Yi
Add a comment at the beginning of extents_status.c to clarify the rules for loading, mapping, modifying, and removing extents and blocks. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250423085257.122685-10-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-15ext4: check env when mapping and modifying extentsZhang Yi
Add ext4_check_map_extents_env() to the places where loading extents, mapping blocks, removing blocks, and modifying extents, excluding the I/O writeback context. This function will verify whether the locking mechanisms in place are adequate. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250423085257.122685-9-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-14ext4: introduce ext4_check_map_extents_env() debug helperZhang Yi
Loading and modifying the extents tree and extent status tree without holding the inode's i_rwsem or the mapping's invalidate_lock is not permitted, except during the I/O writeback. Add a new debug helper ext4_check_map_extents_env(), it will verify whether the extent loading/modifying context is safe. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250423085257.122685-8-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>