Linux kernel documentation tree maintained by Jonathan Corbet http://mirrors.hust.edu.cn/git/lwn.git/atom?h=docs-6.8 2023-11-03T05:38:47+00:00 2023-11-03T05:38:47+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-11-03T05:38:47+00:00 urn:sha1:ecae0bd5173b1014f95a14a8dfbe40ec10367dcf Pull MM updates from Andrew Morton: "Many singleton patches against the MM code. The patch series which are included in this merge do the following: - Kemeng Shi has contributed some compation maintenance work in the series 'Fixes and cleanups to compaction' - Joel Fernandes has a patchset ('Optimize mremap during mutual alignment within PMD') which fixes an obscure issue with mremap()'s pagetable handling during a subsequent exec(), based upon an implementation which Linus suggested - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the following patch series: mm/damon: misc fixups for documents, comments and its tracepoint mm/damon: add a tracepoint for damos apply target regions mm/damon: provide pseudo-moving sum based access rate mm/damon: implement DAMOS apply intervals mm/damon/core-test: Fix memory leaks in core-test mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval - In the series 'Do not try to access unaccepted memory' Adrian Hunter provides some fixups for the recently-added 'unaccepted memory' feature. To increase the feature's checking coverage. 'Plug a few gaps where RAM is exposed without checking if it is unaccepted memory' - In the series 'cleanups for lockless slab shrink' Qi Zheng has done some maintenance work which is preparation for the lockless slab shrinking code - Qi Zheng has redone the earlier (and reverted) attempt to make slab shrinking lockless in the series 'use refcount+RCU method to implement lockless slab shrink' - David Hildenbrand contributes some maintenance work for the rmap code in the series 'Anon rmap cleanups' - Kefeng Wang does more folio conversions and some maintenance work in the migration code. Series 'mm: migrate: more folio conversion and unification' - Matthew Wilcox has fixed an issue in the buffer_head code which was causing long stalls under some heavy memory/IO loads. Some cleanups were added on the way. Series 'Add and use bdev_getblk()' - In the series 'Use nth_page() in place of direct struct page manipulation' Zi Yan has fixed a potential issue with the direct manipulation of hugetlb page frames - In the series 'mm: hugetlb: Skip initialization of gigantic tail struct pages if freed by HVO' has improved our handling of gigantic pages in the hugetlb vmmemmep optimizaton code. This provides significant boot time improvements when significant amounts of gigantic pages are in use - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code rationalization and folio conversions in the hugetlb code - Yin Fengwei has improved mlock()'s handling of large folios in the series 'support large folio for mlock' - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has added statistics for memcg v1 users which are available (and useful) under memcg v2 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable) prctl so that userspace may direct the kernel to not automatically propagate the denial to child processes. The series is named 'MDWE without inheritance' - Kefeng Wang has provided the series 'mm: convert numa balancing functions to use a folio' which does what it says - In the series 'mm/ksm: add fork-exec support for prctl' Stefan Roesch makes is possible for a process to propagate KSM treatment across exec() - Huang Ying has enhanced memory tiering's calculation of memory distances. This is used to permit the dax/kmem driver to use 'high bandwidth memory' in addition to Optane Data Center Persistent Memory Modules (DCPMM). The series is named 'memory tiering: calculate abstract distance based on ACPI HMAT' - In the series 'Smart scanning mode for KSM' Stefan Roesch has optimized KSM by teaching it to retain and use some historical information from previous scans - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the series 'mm: memcg: fix tracking of pending stats updates values' - In the series 'Implement IOCTL to get and optionally clear info about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap which permits us to atomically read-then-clear page softdirty state. This is mainly used by CRIU - Hugh Dickins contributed the series 'shmem,tmpfs: general maintenance', a bunch of relatively minor maintenance tweaks to this code - Matthew Wilcox has increased the use of the VMA lock over file-backed page faults in the series 'Handle more faults under the VMA lock'. Some rationalizations of the fault path became possible as a result - In the series 'mm/rmap: convert page_move_anon_rmap() to folio_move_anon_rmap()' David Hildenbrand has implemented some cleanups and folio conversions - In the series 'various improvements to the GUP interface' Lorenzo Stoakes has simplified and improved the GUP interface with an eye to providing groundwork for future improvements - Andrey Konovalov has sent along the series 'kasan: assorted fixes and improvements' which does those things - Some page allocator maintenance work from Kemeng Shi in the series 'Two minor cleanups to break_down_buddy_pages' - In thes series 'New selftest for mm' Breno Leitao has developed another MM self test which tickles a race we had between madvise() and page faults - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups and an optimization to the core pagecache code - Nhat Pham has added memcg accounting for hugetlb memory in the series 'hugetlb memcg accounting' - Cleanups and rationalizations to the pagemap code from Lorenzo Stoakes, in the series 'Abstract vma_merge() and split_vma()' - Audra Mitchell has fixed issues in the procfs page_owner code's new timestamping feature which was causing some misbehaviours. In the series 'Fix page_owner's use of free timestamps' - Lorenzo Stoakes has fixed the handling of new mappings of sealed files in the series 'permit write-sealed memfd read-only shared mappings' - Mike Kravetz has optimized the hugetlb vmemmap optimization in the series 'Batch hugetlb vmemmap modification operations' - Some buffer_head folio conversions and cleanups from Matthew Wilcox in the series 'Finish the create_empty_buffers() transition' - As a page allocator performance optimization Huang Ying has added automatic tuning to the allocator's per-cpu-pages feature, in the series 'mm: PCP high auto-tuning' - Roman Gushchin has contributed the patchset 'mm: improve performance of accounted kernel memory allocations' which improves their performance by ~30% as measured by a micro-benchmark - folio conversions from Kefeng Wang in the series 'mm: convert page cpupid functions to folios' - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about kmemleak' - Qi Zheng has improved our handling of memoryless nodes by keeping them off the allocation fallback list. This is done in the series 'handle memoryless nodes more appropriately' - khugepaged conversions from Vishal Moola in the series 'Some khugepaged folio conversions'" [ bcachefs conflicts with the dynamically allocated shrinkers have been resolved as per Stephen Rothwell in https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/ with help from Qi Zheng. The clone3 test filtering conflict was half-arsed by yours truly ] * tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits) mm/damon/sysfs: update monitoring target regions for online input commit mm/damon/sysfs: remove requested targets when online-commit inputs selftests: add a sanity check for zswap Documentation: maple_tree: fix word spelling error mm/vmalloc: fix the unchecked dereference warning in vread_iter() zswap: export compression failure stats Documentation: ubsan: drop "the" from article title mempolicy: migration attempt to match interleave nodes mempolicy: mmap_lock is not needed while migrating folios mempolicy: alloc_pages_mpol() for NUMA policy without vma mm: add page_rmappable_folio() wrapper mempolicy: remove confusing MPOL_MF_LAZY dead code mempolicy: mpol_shared_policy_init() without pseudo-vma mempolicy trivia: use pgoff_t in shared mempolicy tree mempolicy trivia: slightly more consistent naming mempolicy trivia: delete those ancient pr_debug()s mempolicy: fix migrate_pages(2) syscall return nr_failed kernfs: drop shared NUMA mempolicy hooks hugetlbfs: drop shared NUMA mempolicy pretence mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets() ... 2023-10-30T20:42:06+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-10-30T20:42:06+00:00 urn:sha1:d5acbc60fafbe0fc94c552ce916dd592cd4c6371 Pull btrfs updates from David Sterba: "New features: - raid-stripe-tree New tree for logical file extent mapping where the physical mapping may not match on multiple devices. This is now used in zoned mode to implement RAID0/RAID1* profiles, but can be used in non-zoned mode as well. The support for RAID56 is in development and will eventually fix the problems with the current implementation. This is a backward incompatible feature and has to be enabled at mkfs time. - simple quota accounting (squota) A simplified mode of qgroup that accounts all space on the initial extent owners (a subvolume), the snapshots are then cheap to create and delete. The deletion of snapshots in fully accounting qgroups is a known CPU/IO performance bottleneck. The squota is not suitable for the general use case but works well for containers where the original subvolume exists for the whole time. This is a backward incompatible feature as it needs extending some structures, but can be enabled on an existing filesystem. - temporary filesystem fsid (temp_fsid) The fsid identifies a filesystem and is hard coded in the structures, which disallows mounting the same fsid found on different devices. For a single device filesystem this is not strictly necessary, a new temporary fsid can be generated on mount e.g. after a device is cloned. This will be used by Steam Deck for root partition A/B testing, or can be used for VM root images. Other user visible changes: - filesystems with partially finished metadata_uuid conversion cannot be mounted anymore and the uuid fixup has to be done by btrfs-progs (btrfstune). Performance improvements: - reduce reservations for checksum deletions (with enabled free space tree by factor of 4), on a sample workload on file with many extents the deletion time decreased by 12% - make extent state merges more efficient during insertions, reduce rb-tree iterations (run time of critical functions reduced by 5%) Core changes: - the integrity check functionality has been removed, this was a debugging feature and removal does not affect other integrity checks like checksums or tree-checker - space reservation changes: - more efficient delayed ref reservations, this avoids building up too much work or overusing or exhausting the global block reserve in some situations - move delayed refs reservation to the transaction start time, this prevents some ENOSPC corner cases related to exhaustion of global reserve - improvements in reducing excessive reservations for block group items - adjust overcommit logic in near full situations, account for one more chunk to eventually allocate metadata chunk, this is mostly relevant for small filesystems (<10GiB) - single device filesystems are scanned but not registered (except seed devices), this allows temp_fsid to work - qgroup iterations do not need GFP_ATOMIC allocations anymore - cleanups, refactoring, reduced data structure size, function parameter simplifications, error handling fixes" * tag 'for-6.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (156 commits) btrfs: open code timespec64 in struct btrfs_inode btrfs: remove redundant log root tree index assignment during log sync btrfs: remove redundant initialization of variable dirty in btrfs_update_time() btrfs: sysfs: show temp_fsid feature btrfs: disable the device add feature for temp-fsid btrfs: disable the seed feature for temp-fsid btrfs: update comment for temp-fsid, fsid, and metadata_uuid btrfs: remove pointless empty log context list check when syncing log btrfs: update comment for struct btrfs_inode::lock btrfs: remove pointless barrier from btrfs_sync_file() btrfs: add and use helpers for reading and writing last_trans_committed btrfs: add and use helpers for reading and writing fs_info->generation btrfs: add and use helpers for reading and writing log_transid btrfs: add and use helpers for reading and writing last_log_commit btrfs: support cloned-device mount capability btrfs: add helper function find_fsid_by_disk btrfs: stop reserving excessive space for block group item insertions btrfs: stop reserving excessive space for block group item updates btrfs: reorder btrfs_inode to fill gaps btrfs: open code btrfs_ordered_inode_tree in btrfs_inode ... 2023-10-30T19:47:13+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-10-30T19:47:13+00:00 urn:sha1:14ab6d425e80674b6a0145f05719b11e82e64824 Pull vfs inode time accessor updates from Christian Brauner: "This finishes the conversion of all inode time fields to accessor functions as discussed on list. Changing timestamps manually as we used to do before is error prone. Using accessors function makes this robust. It does not contain the switch of the time fields to discrete 64 bit integers to replace struct timespec and free up space in struct inode. But after this, the switch can be trivially made and the patch should only affect the vfs if we decide to do it" * tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits) fs: rename inode i_atime and i_mtime fields security: convert to new timestamp accessors selinux: convert to new timestamp accessors apparmor: convert to new timestamp accessors sunrpc: convert to new timestamp accessors mm: convert to new timestamp accessors bpf: convert to new timestamp accessors ipc: convert to new timestamp accessors linux: convert to new timestamp accessors zonefs: convert to new timestamp accessors xfs: convert to new timestamp accessors vboxsf: convert to new timestamp accessors ufs: convert to new timestamp accessors udf: convert to new timestamp accessors ubifs: convert to new timestamp accessors tracefs: convert to new timestamp accessors sysv: convert to new timestamp accessors squashfs: convert to new timestamp accessors server: convert to new timestamp accessors client: convert to new timestamp accessors ... 2023-10-30T19:29:44+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-10-30T19:29:44+00:00 urn:sha1:7352a6765cf5d95888b3952ac89efbb817b4c3cf Pull vfs xattr updates from Christian Brauner: "The 's_xattr' field of 'struct super_block' currently requires a mutable table of 'struct xattr_handler' entries (although each handler itself is const). However, no code in vfs actually modifies the tables. This changes the type of 's_xattr' to allow const tables, and modifies existing file systems to move their tables to .rodata. This is desirable because these tables contain entries with function pointers in them; moving them to .rodata makes it considerably less likely to be modified accidentally or maliciously at runtime" * tag 'vfs-6.7.xattr' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (30 commits) const_structs.checkpatch: add xattr_handler net: move sockfs_xattr_handlers to .rodata shmem: move shmem_xattr_handlers to .rodata overlayfs: move xattr tables to .rodata xfs: move xfs_xattr_handlers to .rodata ubifs: move ubifs_xattr_handlers to .rodata squashfs: move squashfs_xattr_handlers to .rodata smb: move cifs_xattr_handlers to .rodata reiserfs: move reiserfs_xattr_handlers to .rodata orangefs: move orangefs_xattr_handlers to .rodata ocfs2: move ocfs2_xattr_handlers and ocfs2_xattr_handler_map to .rodata ntfs3: move ntfs_xattr_handlers to .rodata nfs: move nfs4_xattr_handlers to .rodata kernfs: move kernfs_xattr_handlers to .rodata jfs: move jfs_xattr_handlers to .rodata jffs2: move jffs2_xattr_handlers to .rodata hfsplus: move hfsplus_xattr_handlers to .rodata hfs: move hfs_xattr_handlers to .rodata gfs2: move gfs2_xattr_handlers_max to .rodata fuse: move fuse_xattr_handlers to .rodata ... 2023-10-30T18:59:05+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-10-30T18:59:05+00:00 urn:sha1:d4e175f2c460fd54011117d835aa017d2d4a8c08 Pull vfs superblock updates from Christian Brauner: "This contains the work to make block device opening functions return a struct bdev_handle instead of just a struct block_device. The same struct bdev_handle is then also passed to block device closing functions. This allows us to propagate context from opening to closing a block device without having to modify all users everytime. Sidenote, in the future we might even want to try and have block device opening functions return a struct file directly but that's a series on top of this. These are further preparatory changes to be able to count writable opens and blocking writes to mounted block devices. That's a separate piece of work for next cycle and for that we absolutely need the changes to btrfs that have been quietly dropped somehow. Originally the series contained a patch that removed the old blkdev_*() helpers. But since this would've caused needles churn in -next for bcachefs we ended up delaying it. The second piece of work addresses one of the major annoyances about the work last cycle, namely that we required dropping s_umount whenever we used the superblock and fs_holder_ops for a block device. The reason for that requirement had been that in some codepaths s_umount could've been taken under disk->open_mutex (that's always been the case, at least theoretically). For example, on surprise block device removal or media change. And opening and closing block devices required grabbing disk->open_mutex as well. So we did the work and went through the block layer and fixed all those places so that s_umount is never taken under disk->open_mutex. This means no more brittle games where we yield and reacquire s_umount during block device opening and closing and no more requirements where block devices need to be closed. Filesystems don't need to care about this. There's a bunch of other follow-up work such as moving block device freezing and thawing to holder operations which makes it work for all block devices and not just the main block device just as we did for surprise removal. But that is for next cycle. Tested with fstests for all major fses, blktests, LTP" * tag 'vfs-6.7.super' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (37 commits) porting: update locking requirements fs: assert that open_mutex isn't held over holder ops block: assert that we're not holding open_mutex over blk_report_disk_dead block: move bdev_mark_dead out of disk_check_media_change block: WARN_ON_ONCE() when we remove active partitions block: simplify bdev_del_partition() fs: Avoid grabbing sb->s_umount under bdev->bd_holder_lock jfs: fix log->bdev_handle null ptr deref in lbmStartIO bcache: Fixup error handling in register_cache() xfs: Convert to bdev_open_by_path() reiserfs: Convert to bdev_open_by_dev/path() ocfs2: Convert to use bdev_open_by_dev() nfs/blocklayout: Convert to use bdev_open_by_dev/path() jfs: Convert to bdev_open_by_dev() f2fs: Convert to bdev_open_by_dev/path() ext4: Convert to bdev_open_by_dev() erofs: Convert to use bdev_open_by_path() btrfs: Convert to bdev_open_by_path() fs: Convert to bdev_open_by_dev() mm/swap: Convert to use bdev_open_by_dev() ... 2023-10-28T11:29:20+00:00 Jan Kara jack@suse.cz 2023-09-27T09:34:26+00:00 urn:sha1:86ec15d00bf85801bda57b5d181a2978f828a8cf Convert btrfs to use bdev_open_by_path() and pass the handle around. We also drop the holder from struct btrfs_device as it is now not needed anymore. CC: David Sterba <dsterba@suse.com> CC: linux-btrfs@vger.kernel.org Acked-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20230927093442.25915-20-jack@suse.cz Signed-off-by: Christian Brauner <brauner@kernel.org> 2023-10-23T17:59:13+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-10-23T17:59:13+00:00 urn:sha1:e017769f4ce20dc0d3fa3220d4d359dcc4431274 Pull btrfs fix from David Sterba: "One more fix for a problem with snapshot of a newly created subvolume that can lead to inconsistent data under some circumstances. Kernel 6.5 added a performance optimization to skip transaction commit for subvolume creation but this could end up with newer data on disk but not linked to other structures. The fix itself is an added condition, the rest of the patch is a parameter added to several functions" * tag 'for-6.6-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: fix unwritten extent buffer after snapshotting a new subvolume 2023-10-23T15:17:30+00:00 Filipe Manana fdmanana@suse.com 2023-10-19T12:19:28+00:00 urn:sha1:eb96e221937af3c7bb8a63208dbab813ca5d3d7e When creating a snapshot of a subvolume that was created in the current transaction, we can end up not persisting a dirty extent buffer that is referenced by the snapshot, resulting in IO errors due to checksum failures when trying to read the extent buffer later from disk. A sequence of steps that leads to this is the following: 1) At ioctl.c:create_subvol() we allocate an extent buffer, with logical address 36007936, for the leaf/root of a new subvolume that has an ID of 291. We mark the extent buffer as dirty, and at this point the subvolume tree has a single node/leaf which is also its root (level 0); 2) We no longer commit the transaction used to create the subvolume at create_subvol(). We used to, but that was recently removed in commit 1b53e51a4a8f ("btrfs: don't commit transaction for every subvol create"); 3) The transaction used to create the subvolume has an ID of 33, so the extent buffer 36007936 has a generation of 33; 4) Several updates happen to subvolume 291 during transaction 33, several files created and its tree height changes from 0 to 1, so we end up with a new root at level 1 and the extent buffer 36007936 is now a leaf of that new root node, which is extent buffer 36048896. The commit root remains as 36007936, since we are still at transaction 33; 5) Creation of a snapshot of subvolume 291, with an ID of 292, starts at ioctl.c:create_snapshot(). This triggers a commit of transaction 33 and we end up at transaction.c:create_pending_snapshot(), in the critical section of a transaction commit. There we COW the root of subvolume 291, which is extent buffer 36048896. The COW operation returns extent buffer 36048896, since there's no need to COW because the extent buffer was created in this transaction and it was not written yet. The we call btrfs_copy_root() against the root node 36048896. During this operation we allocate a new extent buffer to turn into the root node of the snapshot, copy the contents of the root node 36048896 into this snapshot root extent buffer, set the owner to 292 (the ID of the snapshot), etc, and then we call btrfs_inc_ref(). This will create a delayed reference for each leaf pointed by the root node with a reference root of 292 - this includes a reference for the leaf 36007936. After that we set the bit BTRFS_ROOT_FORCE_COW in the root's state. Then we call btrfs_insert_dir_item(), to create the directory entry in in the tree of subvolume 291 that points to the snapshot. This ends up needing to modify leaf 36007936 to insert the respective directory items. Because the bit BTRFS_ROOT_FORCE_COW is set for the root's state, we need to COW the leaf. We end up at btrfs_force_cow_block() and then at update_ref_for_cow(). At update_ref_for_cow() we call btrfs_block_can_be_shared() which returns false, despite the fact the leaf 36007936 is shared - the subvolume's root and the snapshot's root point to that leaf. The reason that it incorrectly returns false is because the commit root of the subvolume is extent buffer 36007936 - it was the initial root of the subvolume when we created it. So btrfs_block_can_be_shared() which has the following logic: int btrfs_block_can_be_shared(struct btrfs_root *root, struct extent_buffer *buf) { if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && buf != root->node && buf != root->commit_root && (btrfs_header_generation(buf) <= btrfs_root_last_snapshot(&root->root_item) || btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) return 1; return 0; } Returns false (0) since 'buf' (extent buffer 36007936) matches the root's commit root. As a result, at update_ref_for_cow(), we don't check for the number of references for extent buffer 36007936, we just assume it's not shared and therefore that it has only 1 reference, so we set the local variable 'refs' to 1. Later on, in the final if-else statement at update_ref_for_cow(): static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, struct extent_buffer *cow, int *last_ref) { (...) if (refs > 1) { (...) } else { (...) btrfs_clear_buffer_dirty(trans, buf); *last_ref = 1; } } So we mark the extent buffer 36007936 as not dirty, and as a result we don't write it to disk later in the transaction commit, despite the fact that the snapshot's root points to it. Attempting to access the leaf or dumping the tree for example shows that the extent buffer was not written: $ btrfs inspect-internal dump-tree -t 292 /dev/sdb btrfs-progs v6.2.2 file tree key (292 ROOT_ITEM 33) node 36110336 level 1 items 2 free space 119 generation 33 owner 292 node 36110336 flags 0x1(WRITTEN) backref revision 1 checksum stored a8103e3e checksum calced a8103e3e fs uuid 90c9a46f-ae9f-4626-9aff-0cbf3e2e3a79 chunk uuid e8c9c885-78f4-4d31-85fe-89e5f5fd4a07 key (256 INODE_ITEM 0) block 36007936 gen 33 key (257 EXTENT_DATA 0) block 36052992 gen 33 checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 total bytes 107374182400 bytes used 38572032 uuid 90c9a46f-ae9f-4626-9aff-0cbf3e2e3a79 The respective on disk region is full of zeroes as the device was trimmed at mkfs time. Obviously 'btrfs check' also detects and complains about this: $ btrfs check /dev/sdb Opening filesystem to check... Checking filesystem on /dev/sdb UUID: 90c9a46f-ae9f-4626-9aff-0cbf3e2e3a79 generation: 33 (33) [1/7] checking root items [2/7] checking extents checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 bad tree block 36007936, bytenr mismatch, want=36007936, have=0 owner ref check failed [36007936 4096] ERROR: errors found in extent allocation tree or chunk allocation [3/7] checking free space tree [4/7] checking fs roots checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29 bad tree block 36007936, bytenr mismatch, want=36007936, have=0 The following tree block(s) is corrupted in tree 292: tree block bytenr: 36110336, level: 1, node key: (256, 1, 0) root 292 root dir 256 not found ERROR: errors found in fs roots found 38572032 bytes used, error(s) found total csum bytes: 16048 total tree bytes: 1265664 total fs tree bytes: 1118208 total extent tree bytes: 65536 btree space waste bytes: 562598 file data blocks allocated: 65978368 referenced 36569088 Fix this by updating btrfs_block_can_be_shared() to consider that an extent buffer may be shared if it matches the commit root and if its generation matches the current transaction's generation. This can be reproduced with the following script: $ cat test.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi # Use a filesystem with a 64K node size so that we have the same node # size on every machine regardless of its page size (on x86_64 default # node size is 16K due to the 4K page size, while on PPC it's 64K by # default). This way we can make sure we are able to create a btree for # the subvolume with a height of 2. mkfs.btrfs -f -n 64K $DEV mount $DEV $MNT btrfs subvolume create $MNT/subvol # Create a few empty files on the subvolume, this bumps its btree # height to 2 (root node at level 1 and 2 leaves). for ((i = 1; i <= 300; i++)); do echo -n > $MNT/subvol/file_$i done btrfs subvolume snapshot -r $MNT/subvol $MNT/subvol/snap umount $DEV btrfs check $DEV Running it on a 6.5 kernel (or any 6.6-rc kernel at the moment): $ ./test.sh Create subvolume '/mnt/sdi/subvol' Create a readonly snapshot of '/mnt/sdi/subvol' in '/mnt/sdi/subvol/snap' Opening filesystem to check... Checking filesystem on /dev/sdi UUID: bbdde2ff-7d02-45ca-8a73-3c36f23755a1 [1/7] checking root items [2/7] checking extents parent transid verify failed on 30539776 wanted 7 found 5 parent transid verify failed on 30539776 wanted 7 found 5 parent transid verify failed on 30539776 wanted 7 found 5 Ignoring transid failure owner ref check failed [30539776 65536] ERROR: errors found in extent allocation tree or chunk allocation [3/7] checking free space tree [4/7] checking fs roots parent transid verify failed on 30539776 wanted 7 found 5 Ignoring transid failure Wrong key of child node/leaf, wanted: (256, 1, 0), have: (2, 132, 0) Wrong generation of child node/leaf, wanted: 5, have: 7 root 257 root dir 256 not found ERROR: errors found in fs roots found 917504 bytes used, error(s) found total csum bytes: 0 total tree bytes: 851968 total fs tree bytes: 393216 total extent tree bytes: 65536 btree space waste bytes: 736550 file data blocks allocated: 0 referenced 0 A test case for fstests will follow soon. Fixes: 1b53e51a4a8f ("btrfs: don't commit transaction for every subvol create") CC: stable@vger.kernel.org # 6.5+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> 2023-10-19T15:56:01+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-10-19T15:56:01+00:00 urn:sha1:7cf4bea77ab60742c128c2ceb4b1b8078887b823 Pull btrfs fix from David Sterba: "Fix a bug in chunk size decision that could lead to suboptimal placement and filling patterns" * tag 'for-6.6-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: fix stripe length calculation for non-zoned data chunk allocation 2023-10-18T11:26:19+00:00 Jeff Layton jlayton@kernel.org 2023-10-04T18:52:08+00:00 urn:sha1:b1c38a1338c90597c7af66985a9e31152ae8cfd3 Convert to using the new inode timestamp accessor functions. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/20231004185347.80880-21-jlayton@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>