kernel/linux.git/fs/Makefile, branch v7.0-rc7

Merge tag 'vfs-7.0-rc1.nullfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2026-02-09T21:41:34+00:00

Pull vfs nullfs update from Christian Brauner: "Add a completely catatonic minimal pseudo filesystem called "nullfs" and make pivot_root() work in the initramfs. Currently pivot_root() does not work on the real rootfs because it cannot be unmounted. Userspace has to recursively delete initramfs contents manually before continuing boot, using the fragile switch_root sequence (overmount + chroot). Add nullfs, a minimal immutable filesystem that serves as the true root of the mount hierarchy. The mutable rootfs (tmpfs/ramfs) is mounted on top of it. This allows userspace to simply: chdir(new_root); pivot_root(".", "."); umount2(".", MNT_DETACH); without the traditional switch_root workarounds. systemd already handles this correctly. It tries pivot_root() first and falls back to MS_MOVE only when that fails. This also means rootfs mounts in unprivileged namespaces no longer need MNT_LOCKED, since the immutable nullfs guarantees nothing can be revealed by unmounting the covering mount. nullfs is a single-instance filesystem (get_tree_single()) marked SB_NOUSER | SB_I_NOEXEC | SB_I_NODEV with an immutable empty root directory. This means sooner or later it can be used to overmount other directories to hide their contents without any additional protection needed. We enable it unconditionally. If we see any real regression we'll hide it behind a boot option. nullfs has extensions beyond this in the future. It will serve as a concept to support the creation of completely empty mount namespaces - which is work coming up in the next cycle" * tag 'vfs-7.0-rc1.nullfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: use nullfs unconditionally as the real rootfs docs: mention nullfs fs: add immutable rootfs fs: add init_pivot_root() fs: ensure that internal tmpfs mount gets mount id zero

fs: report filesystem and file I/O errors to fsnotify

2026-01-13T08:58:01+00:00

Create some wrapper code around struct super_block so that filesystems have a standard way to queue filesystem metadata and file I/O error reports to have them sent to fsnotify. If a filesystem wants to provide an error number, it must supply only negative error numbers. These are stored internally as negative numbers, but they are converted to positive error numbers before being passed to fanotify, per the fanotify(7) manpage. Implementations of super_operations::report_error are passed the raw internal event data. Note that we have to play some shenanigans with mempools and queue_work so that the error handling doesn't happen outside of process context, and the event handler functions (both ->report_error and fsnotify) can handle file I/O error messages without having to worry about whatever locks might be held. This asynchronicity requires that unmount wait for pending events to clear. Add a new callback to the superblock operations structure so that filesystem drivers can themselves respond to file I/O errors if they so desire. This will be used for an upcoming self-healing patchset for XFS. Suggested-by: Christoph Hellwig Signed-off-by: Darrick J. Wong Link: https://patch.msgid.link/176826402610.3490369.4378391061533403171.stgit@frogsfrogsfrogs Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner

fs: add immutable rootfs

2026-01-12T15:52:09+00:00

Currently pivot_root() doesn't work on the real rootfs because it cannot be unmounted. Userspace has to do a recursive removal of the initramfs contents manually before continuing the boot. Really all we want from the real rootfs is to serve as the parent mount for anything that is actually useful such as the tmpfs or ramfs for initramfs unpacking or the rootfs itself. There's no need for the real rootfs to actually be anything meaningful or useful. Add a immutable rootfs called "nullfs" that can be selected via the "nullfs_rootfs" kernel command line option. The kernel will mount a tmpfs/ramfs on top of it, unpack the initramfs and fire up userspace which mounts the rootfs and can then just do: chdir(rootfs); pivot_root(".", "."); umount2(".", MNT_DETACH); and be done with it. (Ofc, userspace can also choose to retain the initramfs contents by using something like pivot_root(".", "/initramfs") without unmounting it.) Technically this also means that the rootfs mount in unprivileged namespaces doesn't need to become MNT_LOCKED anymore as it's guaranteed that the immutable rootfs remains permanently empty so there cannot be anything revealed by unmounting the covering mount. In the future this will also allow us to create completely empty mount namespaces without risking to leak anything. systemd already handles this all correctly as it tries to pivot_root() first and falls back to MS_MOVE only when that fails. This goes back to various discussion in previous years and a LPC 2024 presentation about this very topic. Link: https://patch.msgid.link/20260112-work-immutable-rootfs-v2-3-88dd1c34a204@kernel.org Signed-off-by: Christian Brauner

fs: rename fs_types.h to fs_dirent.h

2025-11-05T08:51:30+00:00

We will split out a bunch of types into a separate header. So free up the appropriate name for it. Link: https://patch.msgid.link/20251104-work-fs-header-v1-1-fb39a2efe39e@kernel.org Signed-off-by: Christian Brauner

Remove bcachefs core code

2025-09-29T20:43:52+00:00

bcachefs was marked 'externally maintained' in 6.17 but the code remained to make the transition smoother. It's now a DKMS module, making the in-kernel code stale, so remove it to avoid any version confusion. Link: https://lore.kernel.org/linux-bcachefs/yokpt2d2g2lluyomtqrdvmkl3amv3kgnipmenobkpgx537kay7@xgcgjviv3n7x/T/ Signed-off-by: Linus Torvalds

fs: split fileattr related helpers into separate file

2025-07-01T20:44:22+00:00

This patch moves function related to file extended attributes manipulations to separate file. Refactoring only. Signed-off-by: Andrey Albershteyn Link: https://lore.kernel.org/20250630-xattrat-syscall-v6-1-c4e3bc35227b@kernel.org Reviewed-by: Amir Goldstein Reviewed-by: Darrick J. Wong Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

fs/resctrl: Add boiler plate for external resctrl code

2025-05-16T09:05:40+00:00

Add Makefile and Kconfig for fs/resctrl. Add ARCH_HAS_CPU_RESCTRL for the common parts of the resctrl interface and make X86_CPU_RESCTRL select this. Adding an include of asm/resctrl.h to linux/resctrl.h allows the /fs/resctrl files to switch over to using this header instead. Co-developed-by: Dave Martin Signed-off-by: Dave Martin Signed-off-by: James Morse Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Shaopeng Tan Reviewed-by: Tony Luck Reviewed-by: Fenghua Yu Reviewed-by: Reinette Chatre Tested-by: Fenghua Yu Tested-by: Carl Worth # arm64 Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Amit Singh Tomar # arm64 Tested-by: Shanker Donthineni # arm64 Tested-by: Babu Moger Tested-by: Tony Luck Link: https://lore.kernel.org/20250515165855.31452-16-james.morse@arm.com

sysv: Remove the filesystem

2025-02-21T09:32:47+00:00

Since 2002 (change "Replace BKL for chain locking with sysvfs-private rwlock") the sysv filesystem was doing IO under a rwlock in its get_block() function (yes, a non-sleepable lock hold over a function used to read inode metadata for all reads and writes). Nobody noticed until syzbot in 2023 [1]. This shows nobody is using the filesystem. Just drop it. [1] https://lore.kernel.org/all/0000000000000ccf9a05ee84f5b0@google.com/ Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20250220163940.10155-2-jack@suse.cz Reviewed-by: Jeff Layton Reviewed-by: "Darrick J. Wong" Signed-off-by: Christian Brauner

reiserfs: The last commit

2024-10-21T14:29:38+00:00

Deprecation period of reiserfs ends with the end of this year so it is time to remove it from the kernel. Acked-by: Darrick J. Wong Acked-by: Christian Brauner Signed-off-by: Jan Kara

bpf: introduce new VFS based BPF kfuncs

2024-08-06T16:01:41+00:00

Add a new variant of bpf_d_path() named bpf_path_d_path() which takes the form of a BPF kfunc and enforces KF_TRUSTED_ARGS semantics onto its arguments. This new d_path() based BPF kfunc variant is intended to address the legacy bpf_d_path() BPF helper's susceptability to memory corruption issues [0, 1, 2] by ensuring to only operate on supplied arguments which are deemed trusted by the BPF verifier. Typically, this means that only pointers to a struct path which have been referenced counted may be supplied. In addition to the new bpf_path_d_path() BPF kfunc, we also add a KF_ACQUIRE based BPF kfunc bpf_get_task_exe_file() and KF_RELEASE counterpart BPF kfunc bpf_put_file(). This is so that the new bpf_path_d_path() BPF kfunc can be used more flexibily from within the context of a BPF LSM program. It's rather common to ascertain the backing executable file for the calling process by performing the following walk current->mm->exe_file while instrumenting a given operation from the context of the BPF LSM program. However, walking current->mm->exe_file directly is never deemed to be OK, and doing so from both inside and outside of BPF LSM program context should be considered as a bug. Using bpf_get_task_exe_file() and in turn bpf_put_file() will allow BPF LSM programs to reliably get and put references to current->mm->exe_file. As of now, all the newly introduced BPF kfuncs within this patch are limited to BPF LSM program types. These can be either sleepable or non-sleepable variants of BPF LSM program types. [0] https://lore.kernel.org/bpf/CAG48ez0ppjcT=QxU-jtCUfb5xQb3mLr=5FcwddF_VKfEBPs_Dg@mail.gmail.com/ [1] https://lore.kernel.org/bpf/20230606181714.532998-1-jolsa@kernel.org/ [2] https://lore.kernel.org/bpf/20220219113744.1852259-1-memxor@gmail.com/ Acked-by: Christian Brauner Signed-off-by: Matt Bobrowski Acked-by: Song Liu Link: https://lore.kernel.org/r/20240731110833.1834742-2-mattbobrowski@google.com Signed-off-by: Alexei Starovoitov