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2025-09-02smb: client: fix spellings in commentsBharath SM
correct spellings in comments Signed-off-by: Bharath SM <bharathsm@microsoft.com> Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-09-02finish_automount(): use __free() to deal with dropping mnt on failureAl Viro
same story as with do_new_mount_fc(). Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02do_new_mount_fc(): use __free() to deal with dropping mnt on failureAl Viro
do_add_mount() consumes vfsmount on success; just follow it with conditional retain_and_null_ptr() on success and we can switch to __free() for mnt and be done with that - unlock_mount() is in the very end. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02finish_automount(): take the lock_mount() analogue into a helperAl Viro
finish_automount() can't use lock_mount() - it treats finding something already mounted as "quitely drop our mount and return 0", not as "mount on top of whatever mounted there". It's been open-coded; let's take it into a helper similar to lock_mount(). "something's already mounted" => -EBUSY, finish_automount() needs to distinguish it from the normal case and it can't happen in other failure cases. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02pivot_root(2): use __free() to deal with struct path in itAl Viro
preparations for making unlock_mount() a __cleanup(); can't have path_put() inside mount_lock scope. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02do_loopback(): use __free(path_put) to deal with old_pathAl Viro
preparations for making unlock_mount() a __cleanup(); can't have path_put() inside mount_lock scope. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02finish_automount(): simplify the ELOOP checkAl Viro
It's enough to check that dentries match; if path->dentry is equal to m->mnt_root, superblocks will match as well. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02move_mount(2): take sanity checks in 'beneath' case into do_lock_mount()Al Viro
We want to mount beneath the given location. For that operation to make sense, location must be the root of some mount that has something under it. Currently we let it proceed if those requirements are not met, with rather meaningless results, and have that bogosity caught further down the road; let's fail early instead - do_lock_mount() doesn't make sense unless those conditions hold, and checking them there makes things simpler. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02do_move_mount(): deal with the checks on old_path earlyAl Viro
1) checking that location we want to move does point to root of some mount can be done before anything else; that property is not going to change and having it already verified simplifies the analysis. 2) checking the type agreement between what we are trying to move and what we are trying to move it onto also belongs in the very beginning - do_lock_mount() might end up switching new_path to something that overmounts the original location, but... the same type agreement applies to overmounts, so we could just as well check against the original location. 3) since we know that old_path->dentry is the root of old_path->mnt, there's no point bothering with path_is_overmounted() in can_move_mount_beneath(); it's simply a check for the mount we are trying to move having non-NULL ->overmount. And with that, we can switch can_move_mount_beneath() to taking old instead of old_path, leaving no uses of old_path past the original checks. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02do_move_mount(): trim local variablesAl Viro
Both 'parent' and 'ns' are used at most once, no point precalculating those... Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02switch do_new_mount_fc() to fc_mount()Al Viro
Prior to the call of do_new_mount_fc() the caller has just done successful vfs_get_tree(). Then do_new_mount_fc() does several checks on resulting superblock, and either does fc_drop_locked() and returns an error or proceeds to unlock the superblock and call vfs_create_mount(). The thing is, there's no reason to delay that unlock + vfs_create_mount() - the tests do not rely upon the state of ->s_umount and fc_drop_locked() put_fs_context() is equivalent to unlock ->s_umount put_fs_context() Doing vfs_create_mount() before the checks allows us to move vfs_get_tree() from caller to do_new_mount_fc() and collapse it with vfs_create_mount() into an fc_mount() call. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02current_chrooted(): use guardsAl Viro
here a use of __free(path_put) for dropping fs_root is enough to make guard(mount_locked_reader) fit... Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02current_chrooted(): don't bother with follow_down_one()Al Viro
All we need here is to follow ->overmount on root mount of namespace... Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02path_is_under(): use guardsAl Viro
... and document that locking requirements for is_path_reachable(). There is one questionable caller in do_listmount() where we are not holding mount_lock *and* might not have the first argument mounted. However, in that case it will immediately return true without having to look at the ancestors. Might be cleaner to move the check into non-LSTM_ROOT case which it really belongs in - there the check is not always true and is_mounted() is guaranteed. Document the locking environments for is_path_reachable() callers: get_peer_under_root() get_dominating_id() do_statmount() do_listmount() Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02mnt_set_expiry(): use guardsAl Viro
The reason why it needs only mount_locked_reader is that there's no lockless accesses of expiry lists. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02has_locked_children(): use guardsAl Viro
... and document the locking requirements of __has_locked_children() Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02propagate_mnt(): use scoped_guard(mount_locked_reader) for mnt_set_mountpoint()Al Viro
Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02check_for_nsfs_mounts(): no need to take locksAl Viro
Currently we are taking mount_writer; what that function needs is either mount_locked_reader (we are not changing anything, we just want to iterate through the subtree) or namespace_shared and a reference held by caller on the root of subtree - that's also enough to stabilize the topology. The thing is, all callers are already holding at least namespace_shared as well as a reference to the root of subtree. Let's make the callers provide locking warranties - don't mess with mount_lock in check_for_nsfs_mounts() itself and document the locking requirements. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02mnt_already_visible(): use guardsAl Viro
clean fit; namespace_shared due to iterating through ns->mounts. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02put_mnt_ns(): use guardsAl Viro
clean fit; guards can't be weaker due to umount_tree() call. Setting emptied_ns requires namespace_excl, but not anything mount_lock-related. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02mark_mounts_for_expiry(): use guardsAl Viro
Clean fit; guards can't be weaker due to umount_tree() calls. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02do_set_group(): use guardsAl Viro
clean fit; namespace_excl to modify propagation graph Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02do_change_type(): use guardsAl Viro
clean fit; namespace_excl to modify propagation graph Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02__is_local_mountpoint(): use guardsAl Viro
clean fit; namespace_shared due to iterating through ns->mounts. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02__detach_mounts(): use guardsAl Viro
Clean fit for guards use; guards can't be weaker due to umount_tree() calls. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02fs/namespace.c: allow to drop vfsmount references via __free(mntput)Al Viro
Note that just as path_put, it should never be done in scope of namespace_sem, be it shared or exclusive. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02introduced guards for mount_lockAl Viro
mount_writer: write_seqlock; that's an equivalent of {un,}lock_mount_hash() mount_locked_reader: read_seqlock_excl; these tend to be open-coded. No bulk conversions, please - if nothing else, quite a few places take use mount_writer form when mount_locked_reader is sufficent. It needs to be dealt with carefully. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02fs/namespace.c: fix the namespace_sem guard messAl Viro
If anything, namespace_lock should be DEFINE_LOCK_GUARD_0, not DEFINE_GUARD. That way we * do not need to feed it a bogus argument * do not get gcc trying to compare an address of static in file variable with -4097 - and, if we are unlucky, trying to keep it in a register, with spills and all such. The same problems apply to grabbing namespace_sem shared. Rename it to namespace_excl, add namespace_shared, convert the existing users: guard(namespace_lock, &namespace_sem) => guard(namespace_excl)() guard(rwsem_read, &namespace_sem) => guard(namespace_shared)() scoped_guard(namespace_lock, &namespace_sem) => scoped_guard(namespace_excl) scoped_guard(rwsem_read, &namespace_sem) => scoped_guard(namespace_shared) Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02Merge tag 'mm-hotfixes-stable-2025-09-01-17-20' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc fixes from Andrew Morton: "17 hotfixes. 13 are cc:stable and the remainder address post-6.16 issues or aren't considered necessary for -stable kernels. 11 of these fixes are for MM. This includes a three-patch series from Harry Yoo which fixes an intermittent boot failure which can occur on x86 systems. And a two-patch series from Alexander Gordeev which fixes a KASAN crash on S390 systems" * tag 'mm-hotfixes-stable-2025-09-01-17-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm: fix possible deadlock in kmemleak x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() mm: introduce and use {pgd,p4d}_populate_kernel() mm: move page table sync declarations to linux/pgtable.h proc: fix missing pde_set_flags() for net proc files mm: fix accounting of memmap pages mm/damon/core: prevent unnecessary overflow in damos_set_effective_quota() kexec: add KEXEC_FILE_NO_CMA as a legal flag kasan: fix GCC mem-intrinsic prefix with sw tags mm/kasan: avoid lazy MMU mode hazards mm/kasan: fix vmalloc shadow memory (de-)population races kunit: kasan_test: disable fortify string checker on kasan_strings() test selftests/mm: fix FORCE_READ to read input value correctly mm/userfaultfd: fix kmap_local LIFO ordering for CONFIG_HIGHPTE ocfs2: prevent release journal inode after journal shutdown rust: mm: mark VmaNew as transparent of_numa: fix uninitialized memory nodes causing kernel panic
2025-09-02f2fs: allocate HOT_DATA for IPU writesJaegeuk Kim
Let's split IPU writes in hot data area to improve the GC efficiency. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2025-09-02Merge tag 'for-6.17-rc4-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - fix a few races related to inode link count - fix inode leak on failure to add link to inode - move transaction aborts closer to where they happen * tag 'for-6.17-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: avoid load/store tearing races when checking if an inode was logged btrfs: fix race between setting last_dir_index_offset and inode logging btrfs: fix race between logging inode and checking if it was logged before btrfs: simplify error handling logic for btrfs_link() btrfs: fix inode leak on failure to add link to inode btrfs: abort transaction on failure to add link to inode
2025-09-02btrfs: fix subvolume deletion lockup caused by inodes xarray raceOmar Sandoval
There is a race condition between inode eviction and inode caching that can cause a live struct btrfs_inode to be missing from the root->inodes xarray. Specifically, there is a window during evict() between the inode being unhashed and deleted from the xarray. If btrfs_iget() is called for the same inode in that window, it will be recreated and inserted into the xarray, but then eviction will delete the new entry, leaving nothing in the xarray: Thread 1 Thread 2 --------------------------------------------------------------- evict() remove_inode_hash() btrfs_iget_path() btrfs_iget_locked() btrfs_read_locked_inode() btrfs_add_inode_to_root() destroy_inode() btrfs_destroy_inode() btrfs_del_inode_from_root() __xa_erase In turn, this can cause issues for subvolume deletion. Specifically, if an inode is in this lost state, and all other inodes are evicted, then btrfs_del_inode_from_root() will call btrfs_add_dead_root() prematurely. If the lost inode has a delayed_node attached to it, then when btrfs_clean_one_deleted_snapshot() calls btrfs_kill_all_delayed_nodes(), it will loop forever because the delayed_nodes xarray will never become empty (unless memory pressure forces the inode out). We saw this manifest as soft lockups in production. Fix it by only deleting the xarray entry if it matches the given inode (using __xa_cmpxchg()). Fixes: 310b2f5d5a94 ("btrfs: use an xarray to track open inodes in a root") Cc: stable@vger.kernel.org # 6.11+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Co-authored-by: Leo Martins <loemra.dev@gmail.com> Signed-off-by: Leo Martins <loemra.dev@gmail.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-02btrfs: fix corruption reading compressed range when block size is smaller ↵Qu Wenruo
than page size [BUG] With 64K page size (aarch64 with 64K page size config) and 4K btrfs block size, the following workload can easily lead to a corrupted read: mkfs.btrfs -f -s 4k $dev > /dev/null mount -o compress $dev $mnt xfs_io -f -c "pwrite -S 0xff 0 64k" $mnt/base > /dev/null echo "correct result:" od -Ad -t x1 $mnt/base xfs_io -f -c "reflink $mnt/base 32k 0 32k" \ -c "reflink $mnt/base 0 32k 32k" \ -c "pwrite -S 0xff 60k 4k" $mnt/new > /dev/null echo "incorrect result:" od -Ad -t x1 $mnt/new umount $mnt This shows the following result: correct result: 0000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff * 0065536 incorrect result: 0000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff * 0032768 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 0061440 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff * 0065536 Notice the zero in the range [32K, 60K), which is incorrect. [CAUSE] With extra trace printk, it shows the following events during od: (some unrelated info removed like CPU and context) od-3457 btrfs_do_readpage: enter r/i=5/258 folio=0(65536) prev_em_start=0000000000000000 The "r/i" is indicating the root and inode number. In our case the file "new" is using ino 258 from fs tree (root 5). Here notice the @prev_em_start pointer is NULL. This means the btrfs_do_readpage() is called from btrfs_read_folio(), not from btrfs_readahead(). od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=0 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=4096 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=8192 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=12288 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=16384 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=20480 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=24576 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=28672 got em start=0 len=32768 These above 32K blocks will be read from the first half of the compressed data extent. od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=32768 got em start=32768 len=32768 Note here there is no btrfs_submit_compressed_read() call. Which is incorrect now. Although both extent maps at 0 and 32K are pointing to the same compressed data, their offsets are different thus can not be merged into the same read. So this means the compressed data read merge check is doing something wrong. od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=36864 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=40960 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=45056 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=49152 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=53248 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=57344 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=61440 skip uptodate od-3457 btrfs_submit_compressed_read: cb orig_bio: file off=0 len=61440 The function btrfs_submit_compressed_read() is only called at the end of folio read. The compressed bio will only have an extent map of range [0, 32K), but the original bio passed in is for the whole 64K folio. This will cause the decompression part to only fill the first 32K, leaving the rest untouched (aka, filled with zero). This incorrect compressed read merge leads to the above data corruption. There were similar problems that happened in the past, commit 808f80b46790 ("Btrfs: update fix for read corruption of compressed and shared extents") is doing pretty much the same fix for readahead. But that's back to 2015, where btrfs still only supports bs (block size) == ps (page size) cases. This means btrfs_do_readpage() only needs to handle a folio which contains exactly one block. Only btrfs_readahead() can lead to a read covering multiple blocks. Thus only btrfs_readahead() passes a non-NULL @prev_em_start pointer. With v5.15 kernel btrfs introduced bs < ps support. This breaks the above assumption that a folio can only contain one block. Now btrfs_read_folio() can also read multiple blocks in one go. But btrfs_read_folio() doesn't pass a @prev_em_start pointer, thus the existing bio force submission check will never be triggered. In theory, this can also happen for btrfs with large folios, but since large folio is still experimental, we don't need to bother it, thus only bs < ps support is affected for now. [FIX] Instead of passing @prev_em_start to do the proper compressed extent check, introduce one new member, btrfs_bio_ctrl::last_em_start, so that the existing bio force submission logic will always be triggered. CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-02btrfs: accept and ignore compression level for lzoCalvin Owens
The compression level is meaningless for lzo, but before commit 3f093ccb95f30 ("btrfs: harden parsing of compression mount options"), it was silently ignored if passed. After that commit, passing a level with lzo fails to mount: BTRFS error: unrecognized compression value lzo:1 It seems reasonable for users to expect that lzo would permit a numeric level option, as all the other algos do, even though the kernel's implementation of LZO currently only supports a single level. Because it has always worked to pass a level, it seems likely to me that users in the real world are relying on doing so. This patch restores the old behavior, giving "lzo:N" the same semantics as all of the other compression algos. To be clear, silly variants like "lzo:one", "lzo:the_first_option", or "lzo:armageddon" also used to work. This isn't meant to suggest that any possible mis-interpretation of mount options that once worked must continue to work forever. This is an exceptional case where it makes sense to preserve compatibility, both because the mis-interpretation is reasonable, and because nothing tangible is sacrificed. Finally update btrfs_show_options() to ignore the level of LZO, as it is only the default level without any extra meaning. Fixes: 3f093ccb95f30 ("btrfs: harden parsing of compression mount options") Reviewed-by: Daniel Vacek <neelx@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Calvin Owens <calvin@wbinvd.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-02btrfs: fix squota compressed stats leakBoris Burkov
The following workload on a squota enabled fs: btrfs subvol create mnt/subvol # ensure subvol extents get accounted sync btrfs qgroup create 1/1 mnt btrfs qgroup assign mnt/subvol 1/1 mnt btrfs qgroup delete mnt/subvol # make the cleaner thread run btrfs filesystem sync mnt sleep 1 btrfs filesystem sync mnt btrfs qgroup destroy 1/1 mnt will fail with EBUSY. The reason is that 1/1 does the quick accounting when we assign subvol to it, gaining its exclusive usage as excl and excl_cmpr. But then when we delete subvol, the decrement happens via record_squota_delta() which does not update excl_cmpr, as squotas does not make any distinction between compressed and normal extents. Thus, we increment excl_cmpr but never decrement it, and are unable to delete 1/1. The two possible fixes are to make squota always mirror excl and excl_cmpr or to make the fast accounting separately track the plain and cmpr numbers. The latter felt cleaner to me so that is what I opted for. Fixes: 1e0e9d5771c3 ("btrfs: add helper for recording simple quota deltas") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-02fsnotify: fix "rewriten"->"rewritten"Xichao Zhao
Trivial fix to spelling mistake in comment text. Signed-off-by: Xichao Zhao <zhao.xichao@vivo.com> Link: https://patch.msgid.link/20250808084213.230592-1-zhao.xichao@vivo.com Signed-off-by: Jan Kara <jack@suse.cz>
2025-09-02procfs: add "pidns" mount optionAleksa Sarai
Since the introduction of pid namespaces, their interaction with procfs has been entirely implicit in ways that require a lot of dancing around by programs that need to construct sandboxes with different PID namespaces. Being able to explicitly specify the pid namespace to use when constructing a procfs super block will allow programs to no longer need to fork off a process which does then does unshare(2) / setns(2) and forks again in order to construct a procfs in a pidns. So, provide a "pidns" mount option which allows such users to just explicitly state which pid namespace they want that procfs instance to use. This interface can be used with fsconfig(2) either with a file descriptor or a path: fsconfig(procfd, FSCONFIG_SET_FD, "pidns", NULL, nsfd); fsconfig(procfd, FSCONFIG_SET_STRING, "pidns", "/proc/self/ns/pid", 0); or with classic mount(2) / mount(8): // mount -t proc -o pidns=/proc/self/ns/pid proc /tmp/proc mount("proc", "/tmp/proc", "proc", MS_..., "pidns=/proc/self/ns/pid"); As this new API is effectively shorthand for setns(2) followed by mount(2), the permission model for this mirrors pidns_install() to avoid opening up new attack surfaces by loosening the existing permission model. In order to avoid having to RCU-protect all users of proc_pid_ns() (to avoid UAFs), attempting to reconfigure an existing procfs instance's pid namespace will error out with -EBUSY. Creating new procfs instances is quite cheap, so this should not be an impediment to most users, and lets us avoid a lot of churn in fs/proc/* for a feature that it seems unlikely userspace would use. Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Link: https://lore.kernel.org/20250805-procfs-pidns-api-v4-2-705f984940e7@cyphar.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-02fuse: remove fuse_readpages_end() null mapping checkJoanne Koong
Remove extra logic in fuse_readpages_end() that checks against null folio mappings. This was added in commit ce534fb05292 ("fuse: allow splice to move pages"): "Since the remove_from_page_cache() + add_to_page_cache_locked() are non-atomic it is possible that the page cache is repopulated in between the two and add_to_page_cache_locked() will fail. This could be fixed by creating a new atomic replace_page_cache_page() function. fuse_readpages_end() needed to be reworked so it works even if page->mapping is NULL for some or all pages which can happen if the add_to_page_cache_locked() failed." Commit ef6a3c63112e ("mm: add replace_page_cache_page() function") added atomic page cache replacement, which means the check against null mappings can be removed. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-09-02fuse: fix references to fuse.rst -> fuse/fuse.rstMiklos Szeredi
Commit 6be0ddb20200 ("Documentation: fuse: Consolidate FUSE docs into its own subdirectory") moved fuse docs to a subdirectory but didn't update references inside the kernel tree. Fixes: 6be0ddb20200 ("Documentation: fuse: Consolidate FUSE docs into its own subdirectory") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202508261621.EaNMWVjm-lkp@intel.com/ Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-09-02fuse: allow synchronous FUSE_INITMiklos Szeredi
FUSE_INIT has always been asynchronous with mount. That means that the server processed this request after the mount syscall returned. This means that FUSE_INIT can't supply the root inode's ID, hence it currently has a hardcoded value. There are other limitations such as not being able to perform getxattr during mount, which is needed by selinux. To remove these limitations allow server to process FUSE_INIT while initializing the in-core super block for the fuse filesystem. This can only be done if the server is prepared to handle this, so add FUSE_DEV_IOC_SYNC_INIT ioctl, which a) lets the server know whether this feature is supported, returning ENOTTY othewrwise. b) lets the kernel know to perform a synchronous initialization The implementation is slightly tricky, since fuse_dev/fuse_conn are set up only during super block creation. This is solved by setting the private data of the fuse device file to a special value ((struct fuse_dev *) 1) and waiting for this to be turned into a proper fuse_dev before commecing with operations on the device file. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-09-02openat2: don't trigger automounts with RESOLVE_NO_XDEVAskar Safin
openat2 had a bug: if we pass RESOLVE_NO_XDEV, then openat2 doesn't traverse through automounts, but may still trigger them. (See the link for full bug report with reproducer.) This commit fixes this bug. Link: https://lore.kernel.org/linux-fsdevel/20250817075252.4137628-1-safinaskar@zohomail.com/ Fixes: fddb5d430ad9fa91b49b1 ("open: introduce openat2(2) syscall") Reviewed-by: Aleksa Sarai <cyphar@cyphar.com> Cc: stable@vger.kernel.org Signed-off-by: Askar Safin <safinaskar@zohomail.com> Link: https://lore.kernel.org/20250825181233.2464822-5-safinaskar@zohomail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-02namei: move cross-device check to __traverse_mountsAskar Safin
This is preparation to RESOLVE_NO_XDEV fix in following commits. Also this commit makes LOOKUP_NO_XDEV logic more clear: now we immediately fail with EXDEV on first mount crossing instead of waiting for very end. No functional change intended Signed-off-by: Askar Safin <safinaskar@zohomail.com> Link: https://lore.kernel.org/20250825181233.2464822-4-safinaskar@zohomail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-02namei: remove LOOKUP_NO_XDEV check from handle_mountsAskar Safin
This is preparation to RESOLVE_NO_XDEV fix in following commits. No functional change intended. The only place that ever looks at ND_JUMPED in nd->state is complete_walk() and we are not going to reach it if handle_mounts() returns an error Signed-off-by: Askar Safin <safinaskar@zohomail.com> Link: https://lore.kernel.org/20250825181233.2464822-3-safinaskar@zohomail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-02namei: move cross-device check to traverse_mountsAskar Safin
This is preparation to RESOLVE_NO_XDEV fix in following commits. No functional change intended Signed-off-by: Askar Safin <safinaskar@zohomail.com> Link: https://lore.kernel.org/20250825181233.2464822-2-safinaskar@zohomail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-01copy_process: pass clone_flags as u64 across calltreeSimon Schuster
With the introduction of clone3 in commit 7f192e3cd316 ("fork: add clone3") the effective bit width of clone_flags on all architectures was increased from 32-bit to 64-bit, with a new type of u64 for the flags. However, for most consumers of clone_flags the interface was not changed from the previous type of unsigned long. While this works fine as long as none of the new 64-bit flag bits (CLONE_CLEAR_SIGHAND and CLONE_INTO_CGROUP) are evaluated, this is still undesirable in terms of the principle of least surprise. Thus, this commit fixes all relevant interfaces of callees to sys_clone3/copy_process (excluding the architecture-specific copy_thread) to consistently pass clone_flags as u64, so that no truncation to 32-bit integers occurs on 32-bit architectures. Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com> Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-2-53fcf5577d57@siemens-energy.com Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-01cramfs: Verify inode mode when loading from diskTetsuo Handa
The inode mode loaded from corrupted disk can be invalid. Do like what commit 0a9e74051313 ("isofs: Verify inode mode when loading from disk") does. Reported-by: syzbot <syzbot+895c23f6917da440ed0d@syzkaller.appspotmail.com> Closes: https://syzkaller.appspot.com/bug?extid=895c23f6917da440ed0d Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Link: https://lore.kernel.org/429b3ef1-13de-4310-9a8e-c2dc9a36234a@I-love.SAKURA.ne.jp Acked-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-01fs: remove vfs_ioctl exportGreg Kroah-Hartman
vfs_ioctl() is no longer called by anything outside of fs/ioctl.c, so remove the global symbol and export as it is not needed. Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/2025083038-carving-amuck-a4ae@gregkh Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-01Merge tag 'fuse-fixes-6.17-rc5' of ↵Christian Brauner
ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse into vfs.fixes fuse fixes for 6.17-rc5 * tag 'fuse-fixes-6.17-rc5' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (6 commits) fuse: Block access to folio overlimit fuse: fix fuseblk i_blkbits for iomap partial writes fuse: reflect cached blocksize if blocksize was changed fuse: prevent overflow in copy_file_range return value fuse: check if copy_file_range() returns larger than requested size fuse: do not allow mapping a non-regular backing file Link: https://lore.kernel.org/CAJfpeguEVMMyw_zCb+hbOuSxdE2Z3Raw=SJsq=Y56Ae6dn2W3g@mail.gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-01inode: fix whitespace issuesChristian Brauner
Fix two minor whitespace issues. Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-01fs: add an icount_read helperJosef Bacik
Instead of doing direct access to ->i_count, add a helper to handle this. This will make it easier to convert i_count to a refcount later. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Link: https://lore.kernel.org/9bc62a84c6b9d6337781203f60837bd98fbc4a96.1756222464.git.josef@toxicpanda.com Signed-off-by: Christian Brauner <brauner@kernel.org>