lwn.git/fs, branch v6.5-rc6

Merge tag 'for-6.5-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2023-08-12T20:28:55+00:00

Pull btrfs fixes from David Sterba: "More fixes, some of them going back to older releases and there are fixes for hangs in stress tests regarding space caching: - fixes and progress tracking for hangs in free space caching, found by test generic/475 - writeback fixes, write pages in integrity mode and skip writing pages that have been written meanwhile - properly clear end of extent range after an error - relocation fixes: - fix race betwen qgroup tree creation and relocation - detect and report invalid reloc roots" * tag 'for-6.5-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: set cache_block_group_error if we find an error btrfs: reject invalid reloc tree root keys with stack dump btrfs: exit gracefully if reloc roots don't match btrfs: avoid race between qgroup tree creation and relocation btrfs: properly clear end of the unreserved range in cow_file_range btrfs: don't wait for writeback on clean pages in extent_write_cache_pages btrfs: don't stop integrity writeback too early btrfs: wait for actual caching progress during allocation

locking: remove spin_lock_prefetch

2023-08-12T16:18:47+00:00

The only remaining consumer is new_inode, where it showed up in 2001 as commit c37fa164f793 ("v2.4.9.9 -> v2.4.9.10") in a historical repo [1] with a changelog which does not mention it. Since then the line got only touched up to keep compiling. While it may have been of benefit back in the day, it is guaranteed to at best not get in the way in the multicore setting -- as the code performs *a lot* of work between the prefetch and actual lock acquire, any contention means the cacheline is already invalid by the time the routine calls spin_lock(). It adds spurious traffic, for short. On top of it prefetch is notoriously tricky to use for single-threaded purposes, making it questionable from the get go. As such, remove it. I admit upfront I did not see value in benchmarking this change, but I can do it if that is deemed appropriate. Removal from new_inode and of the entire thing are in the same patch as requested by Linus, so whatever weird looks can be directed at that guy. Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/fs/inode.c?id=c37fa164f793735b32aa3f53154ff1a7659e6442 [1] Signed-off-by: Mateusz Guzik Signed-off-by: Linus Torvalds

Merge tag 'zonefs-6.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs

2023-08-12T01:35:56+00:00

Pull zonefs fix from Damien Le Moal: - The switch to using iomap for executing a direct synchronous write to sequential files using a zone append BIO overlooked cases where the BIO built by iomap is too large and needs splitting, which is not allowed with zone append. Fix this by using regular write commands instead. The use of zone append commands will be reintroduced later with proper support from iomap. * tag 'zonefs-6.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs: zonefs: fix synchronous direct writes to sequential files

Merge tag 'mm-hotfixes-stable-2023-08-11-13-44' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-11T21:19:20+00:00

Pull misc fixes from Andrew Morton: "14 hotfixes. 11 of these are cc:stable and the remainder address post-6.4 issues, or are not considered suitable for -stable backporting" * tag 'mm-hotfixes-stable-2023-08-11-13-44' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm/damon/core: initialize damo_filter->list from damos_new_filter() nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput selftests: cgroup: fix test_kmem_basic false positives fs/proc/kcore: reinstate bounce buffer for KCORE_TEXT regions MAINTAINERS: add maple tree mailing list mm: compaction: fix endless looping over same migrate block selftests: mm: ksm: fix incorrect evaluation of parameter hugetlb: do not clear hugetlb dtor until allocating vmemmap mm: memory-failure: avoid false hwpoison page mapped error info mm: memory-failure: fix potential unexpected return value from unpoison_memory() mm/swapfile: fix wrong swap entry type for hwpoisoned swapcache page radix tree test suite: fix incorrect allocation size for pthreads crypto, cifs: fix error handling in extract_iter_to_sg() zsmalloc: fix races between modifications of fullness and isolated

btrfs: set cache_block_group_error if we find an error

2023-08-10T15:16:45+00:00

We set cache_block_group_error if btrfs_cache_block_group() returns an error, this is because we could end up not finding space to allocate and mistakenly return -ENOSPC, and which could then abort the transaction with the incorrect errno, and in the case of ENOSPC result in a WARN_ON() that will trip up tests like generic/475. However there's the case where multiple threads can be racing, one thread gets the proper error, and the other thread doesn't actually call btrfs_cache_block_group(), it instead sees ->cached == BTRFS_CACHE_ERROR. Again the result is the same, we fail to allocate our space and return -ENOSPC. Instead we need to set cache_block_group_error to -EIO in this case to make sure that if we do not make our allocation we get the appropriate error returned back to the caller. CC: stable@vger.kernel.org # 4.14+ Signed-off-by: Josef Bacik Signed-off-by: David Sterba

btrfs: reject invalid reloc tree root keys with stack dump

2023-08-10T15:14:42+00:00

[BUG] Syzbot reported a crash that an ASSERT() got triggered inside prepare_to_merge(). That ASSERT() makes sure the reloc tree is properly pointed back by its subvolume tree. [CAUSE] After more debugging output, it turns out we had an invalid reloc tree: BTRFS error (device loop1): reloc tree mismatch, root 8 has no reloc root, expect reloc root key (-8, 132, 8) gen 17 Note the above root key is (TREE_RELOC_OBJECTID, ROOT_ITEM, QUOTA_TREE_OBJECTID), meaning it's a reloc tree for quota tree. But reloc trees can only exist for subvolumes, as for non-subvolume trees, we just COW the involved tree block, no need to create a reloc tree since those tree blocks won't be shared with other trees. Only subvolumes tree can share tree blocks with other trees (thus they have BTRFS_ROOT_SHAREABLE flag). Thus this new debug output proves my previous assumption that corrupted on-disk data can trigger that ASSERT(). [FIX] Besides the dedicated fix and the graceful exit, also let tree-checker to check such root keys, to make sure reloc trees can only exist for subvolumes. CC: stable@vger.kernel.org # 5.15+ Reported-by: syzbot+ae97a827ae1c3336bbb4@syzkaller.appspotmail.com Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba

btrfs: exit gracefully if reloc roots don't match

2023-08-10T15:13:13+00:00

[BUG] Syzbot reported a crash that an ASSERT() got triggered inside prepare_to_merge(). [CAUSE] The root cause of the triggered ASSERT() is we can have a race between quota tree creation and relocation. This leads us to create a duplicated quota tree in the btrfs_read_fs_root() path, and since it's treated as fs tree, it would have ROOT_SHAREABLE flag, causing us to create a reloc tree for it. The bug itself is fixed by a dedicated patch for it, but this already taught us the ASSERT() is not something straightforward for developers. [ENHANCEMENT] Instead of using an ASSERT(), let's handle it gracefully and output extra info about the mismatch reloc roots to help debug. Also with the above ASSERT() removed, we can trigger ASSERT(0)s inside merge_reloc_roots() later. Also replace those ASSERT(0)s with WARN_ON()s. CC: stable@vger.kernel.org # 5.15+ Reported-by: syzbot+ae97a827ae1c3336bbb4@syzkaller.appspotmail.com Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba

btrfs: avoid race between qgroup tree creation and relocation

2023-08-10T15:10:10+00:00

[BUG] Syzbot reported a weird ASSERT() triggered inside prepare_to_merge(). assertion failed: root->reloc_root == reloc_root, in fs/btrfs/relocation.c:1919 ------------[ cut here ]------------ kernel BUG at fs/btrfs/relocation.c:1919! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 9904 Comm: syz-executor.3 Not tainted 6.4.0-syzkaller-08881-g533925cb7604 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 RIP: 0010:prepare_to_merge+0xbb2/0xc40 fs/btrfs/relocation.c:1919 Code: fe e9 f5 (...) RSP: 0018:ffffc9000325f760 EFLAGS: 00010246 RAX: 000000000000004f RBX: ffff888075644030 RCX: 1481ccc522da5800 RDX: ffffc90005c09000 RSI: 00000000000364ca RDI: 00000000000364cb RBP: ffffc9000325f870 R08: ffffffff816f33ac R09: 1ffff9200064bea0 R10: dffffc0000000000 R11: fffff5200064bea1 R12: ffff888075644000 R13: ffff88803b166000 R14: ffff88803b166560 R15: ffff88803b166558 FS: 00007f4e305fd700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056080679c000 CR3: 00000000193ad000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: relocate_block_group+0xa5d/0xcd0 fs/btrfs/relocation.c:3749 btrfs_relocate_block_group+0x7ab/0xd70 fs/btrfs/relocation.c:4087 btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3283 __btrfs_balance+0x1b06/0x2690 fs/btrfs/volumes.c:4018 btrfs_balance+0xbdb/0x1120 fs/btrfs/volumes.c:4402 btrfs_ioctl_balance+0x496/0x7c0 fs/btrfs/ioctl.c:3604 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f4e2f88c389 [CAUSE] With extra debugging, the offending reloc_root is for quota tree (rootid 8). Normally we should not use the reloc tree for quota root at all, as reloc trees are only for subvolume trees. But there is a race between quota enabling and relocation, this happens after commit 85724171b302 ("btrfs: fix the btrfs_get_global_root return value"). Before that commit, for quota and free space tree, we exit immediately if we cannot grab it from fs_info. But now we would try to read it from disk, just as if they are fs trees, this sets ROOT_SHAREABLE flags in such race: Thread A | Thread B ---------------------------------+------------------------------ btrfs_quota_enable() | | | btrfs_get_root_ref() | | |- btrfs_get_global_root() | | | Returned NULL | | |- btrfs_lookup_fs_root() | | | Returned NULL |- btrfs_create_tree() | | | Now quota root item is | | | inserted | |- btrfs_read_tree_root() | | | Got the newly inserted quota root | | |- btrfs_init_fs_root() | | | Set ROOT_SHAREABLE flag [FIX] Get back to the old behavior by returning PTR_ERR(-ENOENT) if the target objectid is not a subvolume tree or data reloc tree. Reported-and-tested-by: syzbot+ae97a827ae1c3336bbb4@syzkaller.appspotmail.com Fixes: 85724171b302 ("btrfs: fix the btrfs_get_global_root return value") Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba

btrfs: properly clear end of the unreserved range in cow_file_range

2023-08-10T15:07:10+00:00

When the call to btrfs_reloc_clone_csums in cow_file_range returns an error, we jump to the out_unlock label with the extent_reserved variable set to false. The cleanup at the label will then call extent_clear_unlock_delalloc on the range from start to end. But we've already added cur_alloc_size to start before the jump, so there might no range be left from the newly incremented start to end. Move the check for 'start < end' so that it is reached by also for the !extent_reserved case. CC: stable@vger.kernel.org # 6.1+ Fixes: a315e68f6e8b ("Btrfs: fix invalid attempt to free reserved space on failure to cow range") Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: don't wait for writeback on clean pages in extent_write_cache_pages

2023-08-10T15:04:09+00:00

__extent_writepage could have started on more pages than the one it was called for. This happens regularly for zoned file systems, and in theory could happen for compressed I/O if the worker thread was executed very quickly. For such pages extent_write_cache_pages waits for writeback to complete before moving on to the next page, which is highly inefficient as it blocks the flusher thread. Port over the PageDirty check that was added to write_cache_pages in commit 515f4a037fb ("mm: write_cache_pages optimise page cleaning") to fix this. CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba