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48 hoursMerge tag 'ext4_for_linus_6.17-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Major ext4 changes for 6.17: - Better scalability for ext4 block allocation - Fix insufficient credits when writing back large folios Miscellaneous bug fixes, especially when handling exteded attriutes, inline data, and fast commit" * tag 'ext4_for_linus_6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (39 commits) ext4: do not BUG when INLINE_DATA_FL lacks system.data xattr ext4: implement linear-like traversal across order xarrays ext4: refactor choose group to scan group ext4: convert free groups order lists to xarrays ext4: factor out ext4_mb_scan_group() ext4: factor out ext4_mb_might_prefetch() ext4: factor out __ext4_mb_scan_group() ext4: fix largest free orders lists corruption on mb_optimize_scan switch ext4: fix zombie groups in average fragment size lists ext4: merge freed extent with existing extents before insertion ext4: convert sbi->s_mb_free_pending to atomic_t ext4: fix typo in CR_GOAL_LEN_SLOW comment ext4: get rid of some obsolete EXT4_MB_HINT flags ext4: utilize multiple global goals to reduce contention ext4: remove unnecessary s_md_lock on update s_mb_last_group ext4: remove unnecessary s_mb_last_start ext4: separate stream goal hits from s_bal_goals for better tracking ext4: add ext4_try_lock_group() to skip busy groups ext4: initialize superblock fields in the kballoc-test.c kunit tests ext4: refactor the inline directory conversion and new directory codepaths ...
8 daysext4: refactor choose group to scan groupBaokun Li
This commit converts the `choose group` logic to `scan group` using previously prepared helper functions. This allows us to leverage xarrays for ordered non-linear traversal, thereby mitigating the "bouncing" issue inherent in the `choose group` mechanism. This also decouples linear and non-linear traversals, leading to cleaner and more readable code. Key changes: * ext4_mb_choose_next_group() is refactored to ext4_mb_scan_groups(). * Replaced ext4_mb_good_group() with ext4_mb_scan_group() in non-linear traversals, and related functions now return error codes instead of group info. * Added ext4_mb_scan_groups_linear() for performing linear scans starting from a specific group for a set number of times. * Linear scans now execute up to sbi->s_mb_max_linear_groups times, so ac_groups_linear_remaining is removed as it's no longer used. * ac->ac_criteria is now used directly instead of passing cr around. Also, ac->ac_criteria is incremented directly after groups scan fails for the corresponding criteria. * Since we're now directly scanning groups instead of finding a good group then scanning, the following variables and flags are no longer needed, s_bal_cX_groups_considered is sufficient. s_bal_p2_aligned_bad_suggestions s_bal_goal_fast_bad_suggestions s_bal_best_avail_bad_suggestions EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-17-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: convert free groups order lists to xarraysBaokun Li
While traversing the list, holding a spin_lock prevents load_buddy, making direct use of ext4_try_lock_group impossible. This can lead to a bouncing scenario where spin_is_locked(grp_A) succeeds, but ext4_try_lock_group() fails, forcing the list traversal to repeatedly restart from grp_A. In contrast, linear traversal directly uses ext4_try_lock_group(), avoiding this bouncing. Therefore, we need a lockless, ordered traversal to achieve linear-like efficiency. Therefore, this commit converts both average fragment size lists and largest free order lists into ordered xarrays. In an xarray, the index represents the block group number and the value holds the block group information; a non-empty value indicates the block group's presence. While insertion and deletion complexity remain O(1), lookup complexity changes from O(1) to O(nlogn), which may slightly reduce single-threaded performance. Additionally, xarray insertions might fail, potentially due to memory allocation issues. However, since we have linear traversal as a fallback, this isn't a major problem. Therefore, we've only added a warning message for insertion failures here. A helper function ext4_mb_find_good_group_xarray() is added to find good groups in the specified xarray starting at the specified position start, and when it reaches ngroups-1, it wraps around to 0 and then to start-1. This ensures an ordered traversal within the xarray. Performance test results are as follows: Single-process operations on an empty disk show negligible impact, while multi-process workloads demonstrate a noticeable performance gain. |CPU: Kunpeng 920 | P80 | P1 | |Memory: 512GB |------------------------|-------------------------| |960GB SSD (0.5GB/s)| base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 20097 | 19555 (-2.6%) | 316141 | 315636 (-0.2%) | |mb_optimize_scan=1 | 13318 | 15496 (+16.3%) | 325273 | 323569 (-0.5%) | |CPU: AMD 9654 * 2 | P96 | P1 | |Memory: 1536GB |------------------------|-------------------------| |960GB SSD (1GB/s) | base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 53603 | 53192 (-0.7%) | 214243 | 212678 (-0.7%) | |mb_optimize_scan=1 | 20887 | 37636 (+80.1%) | 213632 | 214189 (+0.2%) | [ Applied spelling fixes per discussion on the ext4-list see thread referened in the Link tag. --tytso] Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-16-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: convert sbi->s_mb_free_pending to atomic_tBaokun Li
Previously, s_md_lock was used to protect s_mb_free_pending during modifications, while smp_mb() ensured fresh reads, so s_md_lock just guarantees the atomicity of s_mb_free_pending. Thus we optimized it by converting s_mb_free_pending into an atomic variable, thereby eliminating s_md_lock and minimizing lock contention. This also prepares for future lockless merging of free extents. Following this modification, s_md_lock is exclusively responsible for managing insertions and deletions within s_freed_data_list, along with operations involving list_splice. Performance test data follows: Test: Running will-it-scale/fallocate2 on CPU-bound containers. Observation: Average fallocate operations per container per second. |CPU: Kunpeng 920 | P80 | P1 | |Memory: 512GB |------------------------|-------------------------| |960GB SSD (0.5GB/s)| base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 19628 | 20043 (+2.1%) | 320885 | 314331 (-2.0%) | |mb_optimize_scan=1 | 7129 | 7290 (+2.2%) | 321275 | 324226 (+0.9%) | |CPU: AMD 9654 * 2 | P96 | P1 | |Memory: 1536GB |------------------------|-------------------------| |960GB SSD (1GB/s) | base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 53760 | 54999 (+2.3%) | 213145 | 214380 (+0.5%) | |mb_optimize_scan=1 | 12716 | 13497 (+6.1%) | 215262 | 216276 (+0.4%) | 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/20250714130327.1830534-9-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: fix typo in CR_GOAL_LEN_SLOW commentBaokun Li
Remove the superfluous "find_". Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-8-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: get rid of some obsolete EXT4_MB_HINT flagsBaokun Li
Since nobody has used these EXT4_MB_HINT flags for ages, let's remove them. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-7-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: utilize multiple global goals to reduce contentionBaokun Li
When allocating data blocks, if the first try (goal allocation) fails and stream allocation is on, it tries a global goal starting from the last group we used (s_mb_last_group). This helps cluster large files together to reduce free space fragmentation, and the data block contiguity also accelerates write-back to disk. However, when multiple processes allocate blocks, having just one global goal means they all fight over the same group. This drastically lowers the chances of extents merging and leads to much worse file fragmentation. To mitigate this multi-process contention, we now employ multiple global goals, with the number of goals being the minimum between the number of possible CPUs and one-quarter of the filesystem's total block group count. To ensure a consistent goal for each inode, we select the corresponding goal by taking the inode number modulo the total number of goals. Performance test data follows: Test: Running will-it-scale/fallocate2 on CPU-bound containers. Observation: Average fallocate operations per container per second. |CPU: Kunpeng 920 | P80 | P1 | |Memory: 512GB |------------------------|-------------------------| |960GB SSD (0.5GB/s)| base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 9636 | 19628 (+103%) | 337597 | 320885 (-4.9%) | |mb_optimize_scan=1 | 4834 | 7129 (+47.4%) | 341440 | 321275 (-5.9%) | |CPU: AMD 9654 * 2 | P96 | P1 | |Memory: 1536GB |------------------------|-------------------------| |960GB SSD (1GB/s) | base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 22341 | 53760 (+140%) | 219707 | 213145 (-2.9%) | |mb_optimize_scan=1 | 9177 | 12716 (+38.5%) | 215732 | 215262 (+0.2%) | Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-6-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: remove unnecessary s_md_lock on update s_mb_last_groupBaokun Li
After we optimized the block group lock, we found another lock contention issue when running will-it-scale/fallocate2 with multiple processes. The fallocate's block allocation and the truncate's block release were fighting over the s_md_lock. The problem is, this lock protects totally different things in those two processes: the list of freed data blocks (s_freed_data_list) when releasing, and where to start looking for new blocks (mb_last_group) when allocating. Now we only need to track s_mb_last_group and no longer need to track s_mb_last_start, so we don't need the s_md_lock lock to ensure that the two are consistent. Since s_mb_last_group is merely a hint and doesn't require strong synchronization, READ_ONCE/WRITE_ONCE is sufficient. Besides, the s_mb_last_group data type only requires ext4_group_t (i.e., unsigned int), rendering unsigned long superfluous. Performance test data follows: Test: Running will-it-scale/fallocate2 on CPU-bound containers. Observation: Average fallocate operations per container per second. |CPU: Kunpeng 920 | P80 | P1 | |Memory: 512GB |------------------------|-------------------------| |960GB SSD (0.5GB/s)| base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 4821 | 9636 (+99.8%) | 314065 | 337597 (+7.4%) | |mb_optimize_scan=1 | 4784 | 4834 (+1.04%) | 316344 | 341440 (+7.9%) | |CPU: AMD 9654 * 2 | P96 | P1 | |Memory: 1536GB |------------------------|-------------------------| |960GB SSD (1GB/s) | base | patched | base | patched | |-------------------|-------|----------------|--------|----------------| |mb_optimize_scan=0 | 15371 | 22341 (+45.3%) | 205851 | 219707 (+6.7%) | |mb_optimize_scan=1 | 6101 | 9177 (+50.4%) | 207373 | 215732 (+4.0%) | Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-5-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: remove unnecessary s_mb_last_startBaokun Li
Since stream allocation does not use ac->ac_f_ex.fe_start, it is set to -1 by default, so the no longer needed sbi->s_mb_last_start is removed. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-4-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: separate stream goal hits from s_bal_goals for better trackingBaokun Li
In ext4_mb_regular_allocator(), after the call to ext4_mb_find_by_goal() fails to achieve the inode goal, allocation continues with the stream allocation global goal. Currently, hits for both are combined in sbi->s_bal_goals, hindering accurate optimization. This commit separates global goal hits into sbi->s_bal_stream_goals. Since stream allocation doesn't use ac->ac_g_ex.fe_start, set fe_start to -1. This prevents stream allocations from being counted in s_bal_goals. Also clear EXT4_MB_HINT_TRY_GOAL to avoid calling ext4_mb_find_by_goal again. After adding `stream_goal_hits`, `/proc/fs/ext4/sdx/mb_stats` will show: mballoc: reqs: 840347 success: 750992 groups_scanned: 1230506 cr_p2_aligned_stats: hits: 21531 groups_considered: 411664 extents_scanned: 21531 useless_loops: 0 bad_suggestions: 6 cr_goal_fast_stats: hits: 111222 groups_considered: 1806728 extents_scanned: 467908 useless_loops: 0 bad_suggestions: 13 cr_best_avail_stats: hits: 36267 groups_considered: 1817631 extents_scanned: 156143 useless_loops: 0 bad_suggestions: 204 cr_goal_slow_stats: hits: 106396 groups_considered: 5671710 extents_scanned: 22540056 useless_loops: 123747 cr_any_free_stats: hits: 138071 groups_considered: 724692 extents_scanned: 23615593 useless_loops: 585 extents_scanned: 46804261 goal_hits: 1307 stream_goal_hits: 236317 len_goal_hits: 155549 2^n_hits: 21531 breaks: 225096 lost: 35062 buddies_generated: 40/40 buddies_time_used: 48004 preallocated: 5962467 discarded: 4847560 Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-3-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
8 daysext4: add ext4_try_lock_group() to skip busy groupsBaokun Li
When ext4 allocates blocks, we used to just go through the block groups one by one to find a good one. But when there are tons of block groups (like hundreds of thousands or even millions) and not many have free space (meaning they're mostly full), it takes a really long time to check them all, and performance gets bad. So, we added the "mb_optimize_scan" mount option (which is on by default now). It keeps track of some group lists, so when we need a free block, we can just grab a likely group from the right list. This saves time and makes block allocation much faster. But when multiple processes or containers are doing similar things, like constantly allocating 8k blocks, they all try to use the same block group in the same list. Even just two processes doing this can cut the IOPS in half. For example, one container might do 300,000 IOPS, but if you run two at the same time, the total is only 150,000. Since we can already look at block groups in a non-linear way, the first and last groups in the same list are basically the same for finding a block right now. Therefore, add an ext4_try_lock_group() helper function to skip the current group when it is locked by another process, thereby avoiding contention with other processes. This helps ext4 make better use of having multiple block groups. Also, to make sure we don't skip all the groups that have free space when allocating blocks, we won't try to skip busy groups anymore when ac_criteria is CR_ANY_FREE. Performance test data follows: Test: Running will-it-scale/fallocate2 on CPU-bound containers. Observation: Average fallocate operations per container per second. |CPU: Kunpeng 920 | P80 | |Memory: 512GB |-------------------------| |960GB SSD (0.5GB/s)| base | patched | |-------------------|-------|-----------------| |mb_optimize_scan=0 | 2667 | 4821 (+80.7%) | |mb_optimize_scan=1 | 2643 | 4784 (+81.0%) | |CPU: AMD 9654 * 2 | P96 | |Memory: 1536GB |-------------------------| |960GB SSD (1GB/s) | base | patched | |-------------------|-------|-----------------| |mb_optimize_scan=0 | 3450 | 15371 (+345%) | |mb_optimize_scan=1 | 3209 | 6101 (+90.0%) | Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250714130327.1830534-2-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-17ext4: refactor the inline directory conversion and new directory codepathsTheodore Ts'o
There was a lot of common code in the codepaths used to convert an inline directory and to creaet a new directory. To address this, rename ext4_init_dot_dotdot() to ext4_init_dirblock() and then move common code into that function. This reduces the lines of code count in fs/ext4/inline.c and fs/ext4/namei.c, as well as reducing the size of their object files. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Link: https://patch.msgid.link/20250712181249.434530-3-tytso@mit.edu Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-14ext4: limit the maximum folio orderZhang Yi
In environments with a page size of 64KB, the maximum size of a folio can reach up to 128MB. Consequently, during the write-back of folios, the 'rsv_blocks' will be overestimated to 1,577, which can make pressure on the journal space where the journal is small. This can easily exceed the limit of a single transaction. Besides, an excessively large folio is meaningless and will instead increase the overhead of traversing the bhs within the folio. Therefore, limit the maximum order of a folio to 2048 filesystem blocks. Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Reported-by: Joseph Qi <jiangqi903@gmail.com> Closes: https://lore.kernel.org/linux-ext4/CA+G9fYsyYQ3ZL4xaSg1-Tt5Evto7Zd+hgNWZEa9cQLbahA1+xg@mail.gmail.com/ Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250707140814.542883-12-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-13ext4: replace ext4_writepage_trans_blocks()Zhang Yi
After ext4 supports large folios, the semantics of reserving credits in pages is no longer applicable. In most scenarios, reserving credits in extents is sufficient. Therefore, introduce ext4_chunk_trans_extent() to replace ext4_writepage_trans_blocks(). move_extent_per_page() is the only remaining location where we are still processing extents in pages. 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/20250707140814.542883-10-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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>
2025-05-20ext4: 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: 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: 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: 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
2025-05-14ext4: 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>
2025-05-14ext4: factor out is_special_ino()Zhang Yi
Factor out the helper is_special_ino() to facilitate the checking of special inodes in the subsequent patches. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250423085257.122685-7-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-14ext4: prevent stale extent cache entries caused by concurrent I/O writebackZhang Yi
Currently, in the I/O writeback path, ext4_map_blocks() may attempt to cache additional unrelated extents in the extent status tree without holding the inode's i_rwsem and the mapping's invalidate_lock. This can lead to stale extent status entries remaining in certain scenarios, potentially causing data corruption. For example, when performing a collapse range in ext4_collapse_range(), it clears the extent cache and dirty pages before removing blocks and shifting extents. It also holds the i_data_sem during these two operations. However, both ext4_ext_remove_space() and ext4_ext_shift_extents() may briefly release the i_data_sem if journal credits are insufficient (ext4_datasem_ensure_credits()). If another writeback process writes dirty pages from other regions during this interval, it may cache extents that are about to be modified. Unless ext4_collapse_range() explicitly clears the extent cache again, these cached entries can become stale and inconsistent with the actual extents. 0 a n b c m | | | | | | [www][wwwwww][wwwwwwww]...[wwwww][wwww]... | | N M Assume that block a is dirty. The collapse range operation is removing data from n to m and drops i_data_sem immediately after removing the extent from b to c. At the same time, a concurrent writeback begins to write back block a; it will reloads the extent from [n, b) into the extent status tree since it does not hold the i_rwsem or the invalidate_lock. After the collapse range operation, it left the stale extent [n, b), which points logical block n to N, but the actual physical block of n should be M. Similarly, both ext4_insert_range() and ext4_truncate() have the same problem. ext4_punch_hole() survived since it re-add a hole extent entry after removing space since commit 9f1118223aa0 ("ext4: add a hole extent entry in cache after punch"). In most cases, during dirty page writeback, the block mapping information is likely to be found in the extent cache, making it less necessary to search for physical extents. Consequently, loading unrelated extent caches during writeback appears to be ineffective. Therefore, fix this by adds EXT4_EX_NOCACHE in the writeback path to prevent caching of unrelated extents, eliminating this potential source of corruption. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250423085257.122685-4-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-14ext4: generalize EXT4_GET_BLOCKS_IO_SUBMIT flag usageZhang Yi
Currently, the EXT4_GET_BLOCKS_IO_SUBMIT flag is only used during data writeback to indicate that in ordered mode, the journal commit thread should skip re-submitting data and simply wait for I/O completion. To prepare for later patches that need to detect I/O submission context in ext4_map_blocks(), generalizes the meaning of EXT4_GET_BLOCKS_IO_SUBMIT. This flag will be set during: 1) data I/O writeback, 2) I/O completion extents conversion, 3) journal performing commit in fast_commit. This change doesn't affect current usage of this flag and provides a clear way to identify I/O submission context. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250423085257.122685-3-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-08ext4: convert s_fc_lock to mutex typeHarshad Shirwadkar
This allows us to hold s_fc_lock during kmem_cache_* functions, which is needed in the following patch. Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250508175908.1004880-9-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-08ext4: temporarily elevate commit thread priorityHarshad Shirwadkar
Unlike JBD2 based full commits, there is no dedicated journal thread for fast commits. Thus to reduce scheduling delays between IO submission and completion, temporarily elevate the committer thread's priority to match the configured priority of the JBD2 journal thread. Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250508175908.1004880-8-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-08ext4: drop i_fc_updates from inode fc infoHarshad Shirwadkar
The new logic introduced in this series does not require tracking number of active handles open on an inode. So, drop it. Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250508175908.1004880-6-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-08ext4: rework fast commit commit pathHarshad Shirwadkar
This patch reworks fast commit's commit path to remove locking the journal for the entire duration of a fast commit. Instead, we only lock the journal while marking all the eligible inodes as "committing". This allows handles to make progress in parallel with the fast commit. Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> Link: https://patch.msgid.link/20250508175908.1004880-5-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-05-08ext4: convert i_fc_lock to spinlockHarshad Shirwadkar
Convert ext4_inode_info->i_fc_lock to spinlock to avoid sleeping in invalid contexts. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> Link: https://patch.msgid.link/20250508175908.1004880-2-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-21ext4: Make sb update interval tunableOjaswin Mujoo
Currently, outside error paths, we auto commit the super block after 1 hour has passed and 16MB worth of updates have been written since last commit. This is a policy decision so make this tunable while keeping the defaults same. This is useful if user wants to tweak the superblock behavior or for debugging the codepath by allowing to trigger it more frequently. We can now tweak the super block update using sb_update_sec and sb_update_kb files in /sys/fs/ext4/<dev>/ Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/950fb8c9b2905620e16f02a3b9eeea5a5b6cb87e.1742279837.git.ojaswin@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-21ext4: avoid journaling sb update on error if journal is destroyingOjaswin Mujoo
Presently we always BUG_ON if trying to start a transaction on a journal marked with JBD2_UNMOUNT, since this should never happen. However, while ltp running stress tests, it was observed that in case of some error handling paths, it is possible for update_super_work to start a transaction after the journal is destroyed eg: (umount) ext4_kill_sb kill_block_super generic_shutdown_super sync_filesystem /* commits all txns */ evict_inodes /* might start a new txn */ ext4_put_super flush_work(&sbi->s_sb_upd_work) /* flush the workqueue */ jbd2_journal_destroy journal_kill_thread journal->j_flags |= JBD2_UNMOUNT; jbd2_journal_commit_transaction jbd2_journal_get_descriptor_buffer jbd2_journal_bmap ext4_journal_bmap ext4_map_blocks ... ext4_inode_error ext4_handle_error schedule_work(&sbi->s_sb_upd_work) /* work queue kicks in */ update_super_work jbd2_journal_start start_this_handle BUG_ON(journal->j_flags & JBD2_UNMOUNT) Hence, introduce a new mount flag to indicate journal is destroying and only do a journaled (and deferred) update of sb if this flag is not set. Otherwise, just fallback to an un-journaled commit. Further, in the journal destroy path, we have the following sequence: 1. Set mount flag indicating journal is destroying 2. force a commit and wait for it 3. flush pending sb updates This sequence is important as it ensures that, after this point, there is no sb update that might be journaled so it is safe to update the sb outside the journal. (To avoid race discussed in 2d01ddc86606) Also, we don't need a similar check in ext4_grp_locked_error since it is only called from mballoc and AFAICT it would be always valid to schedule work here. Fixes: 2d01ddc86606 ("ext4: save error info to sb through journal if available") Reported-by: Mahesh Kumar <maheshkumar657g@gmail.com> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/9613c465d6ff00cd315602f99283d5f24018c3f7.1742279837.git.ojaswin@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-17ext4: remove redundant function ext4_has_metadata_csumEric Biggers
Since commit f2b4fa19647e ("ext4: switch to using the crc32c library"), ext4_has_metadata_csum() is just an alias for ext4_has_feature_metadata_csum(). ext4_has_feature_metadata_csum() is generated by EXT4_FEATURE_RO_COMPAT_FUNCS and uses the regular naming convention for checking a single ext4 feature. Therefore, remove ext4_has_metadata_csum() and update all its callers to use ext4_has_feature_metadata_csum() directly. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Link: https://patch.msgid.link/20250207031335.42637-1-ebiggers@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-16ext4: remove unused input "inode" in ext4_find_dest_deKemeng Shi
Remove unused input "inode" in ext4_find_dest_de. Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Link: https://patch.msgid.link/20250123162050.2114499-4-shikemeng@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>
2025-03-13ext4: add EXT4_FLAGS_EMERGENCY_RO bitBaokun Li
EXT4_FLAGS_EMERGENCY_RO Indicates that the current file system has become read-only due to some error. Compared to SB_RDONLY, setting it does not require a lock because we won't clear it, which avoids over-coupling with vfs freeze. Also, add a helper function ext4_emergency_ro() to check if the bit is set. 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/20250122114130.229709-3-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-13ext4: convert EXT4_FLAGS_* defines to enumBaokun Li
Do away with the defines and use an enum as it's cleaner. 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/20250122114130.229709-2-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-13ext4: pack holes in ext4_inode_infoBaokun Li
When CONFIG_DEBUG_SPINLOCK is not enabled (general case), there are four 4 bytes holes and one 2 bytes hole in struct ext4_inode_info. Move the members to pack the four 4 bytes holes. 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/20250122110533.4116662-10-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-13ext4: remove unused member 'i_unwritten' from 'ext4_inode_info'Baokun Li
After commit 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure"), no one cares about the value of i_unwritten, so there is no need to maintain this variable, remove it, and clean up the associated logic. Suggested-by: Zhang Yi <yi.zhang@huawei.com> 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/20250122110533.4116662-9-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-13ext4: abort journal on data writeback failure if in data_err=abort modeBaokun Li
The data_err=abort was initially introduced to address users' worries about data corruption spreading unnoticed. With direct writes, we can rely on return values to confirm successful writes to disk. But with buffered writes, a successful return only means the data has been written to memory. Users have no way of knowing if the data has actually written it to disk unless they use fsync (which impacts performance and can sometimes miss errors). The current data_err=abort implementation relies on the ordered data list, but past changes have inadvertently altered its behavior. For example, if an extent is unwritten, we do not add the inode to the ordered data list. Therefore, jbd2 will not wait for the data write-back of that inode to complete and check for errors in the inode mapping. Moreover, the checks performed by jbd2 can also miss errors. Now, all buffered writes eventually call ext4_end_bio(), where I/O errors are checked. Therefore, we can check for the data_err=abort mode at this point and abort the journal in a kworker (due to the interrupt context). Therefore, when data_err=abort is enabled, the journal is aborted in ext4_end_io_end() when an I/O error is detected in ext4_end_bio() to make users who are concerned about the contents of the file happy. Suggested-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/c7ab26f3-85ad-4b31-b132-0afb0e07bf79@huawei.com 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/20250122110533.4116662-6-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-13ext4: do not convert the unwritten extents if data writeback failsBaokun Li
When dioread_nolock is turned on (the default), it will convert unwritten extents to written at ext4_end_io_end(), even if the data writeback fails. It leads to the possibility that stale data may be exposed when the physical block corresponding to the file data is read-only (i.e., writes return -EIO, but reads are normal). Therefore a new ext4_io_end->flags EXT4_IO_END_FAILED is added, which indicates that some bio write-back failed in the current ext4_io_end. When this flag is set, the unwritten to written conversion is no longer performed. Users can read the data normally until the caches are dropped, after that, the failed extents can only be read to all 0. 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/20250122110533.4116662-3-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-13ext4: Replace ext4_da_write_inline_data_begin() with ↵Julian Sun
ext4_generic_write_inline_data(). Replace the call to ext4_da_write_inline_data_begin() with ext4_generic_write_inline_data(), and delete the ext4_da_write_inline_data_begin(). Signed-off-by: Julian Sun <sunjunchao2870@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250107045710.1837756-1-sunjunchao2870@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-02-10ext4: refactor ext4_punch_hole()Zhang Yi
The current implementation of ext4_punch_hole() contains complex position calculations and stale error tags. To improve the code's clarity and maintainability, it is essential to clean up the code and improve its readability, this can be achieved by: a) simplifying and renaming variables; b) eliminating unnecessary position calculations; c) writing back all data in data=journal mode, and drop page cache from the original offset to the end, rather than using aligned blocks, d) renaming the stale error tags. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/20241220011637.1157197-5-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-02-10ext4: remove writable userspace mappings before truncating page cacheZhang Yi
When zeroing a range of folios on the filesystem which block size is less than the page size, the file's mapped blocks within one page will be marked as unwritten, we should remove writable userspace mappings to ensure that ext4_page_mkwrite() can be called during subsequent write access to these partial folios. Otherwise, data written by subsequent mmap writes may not be saved to disk. $mkfs.ext4 -b 1024 /dev/vdb $mount /dev/vdb /mnt $xfs_io -t -f -c "pwrite -S 0x58 0 4096" -c "mmap -rw 0 4096" \ -c "mwrite -S 0x5a 2048 2048" -c "fzero 2048 2048" \ -c "mwrite -S 0x59 2048 2048" -c "close" /mnt/foo $od -Ax -t x1z /mnt/foo 000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 * 000800 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59 * 001000 $umount /mnt && mount /dev/vdb /mnt $od -Ax -t x1z /mnt/foo 000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 * 000800 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 001000 Fix this by introducing ext4_truncate_page_cache_block_range() to remove writable userspace mappings when truncating a partial folio range. Additionally, move the journal data mode-specific handlers and truncate_pagecache_range() into this function, allowing it to serve as a common helper that correctly manages the page cache in preparation for block range manipulations. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/20241220011637.1157197-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2024-12-01ext4: switch to using the crc32c libraryEric Biggers
Now that the crc32c() library function directly takes advantage of architecture-specific optimizations, it is unnecessary to go through the crypto API. Just use crc32c(). This is much simpler, and it improves performance due to eliminating the crypto API overhead. Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Acked-by: Theodore Ts'o <tytso@mit.edu> Link: https://lore.kernel.org/r/20241202010844.144356-17-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
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() ...
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