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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- "khugepaged: add mTHP collapse support" (Nico Pache)
Provide khugepaged with the capability to collapse anonymous memory
regions to mTHPs
- "Remove CONFIG_READ_ONLY_THP_FOR_FS and enable file THP for writable
files" (Zi Yan)
Remove the READ_ONLY_THP_FOR_FS check in file_thp_enabled(), so that
khugepaged and MADV_COLLAPSE can run on filesystems with PMD THP
pagecache support even without READ_ONLY_THP_FOR_FS enabled
- "make MM selftests more CI friendly" (Mike Rapoport)
General fixes and cleanups to the MM selftests. Also move more MM
selftests under the kselftest framework, making them more amenable to
ongoing CI testing
- "selftests/mm: fix failures and robustness improvements" and
"selftests/mm: assorted fixes for hmm-tests" (Sayali Patil)
Fix several issues in MM selftests which were revealed by powerpc 64k
pagesize
* tag 'mm-stable-2026-06-23-08-55' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (118 commits)
Revert "mm: limit filemap_fault readahead to VMA boundaries"
mm/vmscan: pass NULL to trace vmscan node reclaim
mm: use mapping_mapped to simplify the code
selftests/mm: fix exclusive_cow test fork() handling
selftests/mm: remove hardcoded THP sizing assumptions in hmm tests
selftests/mm: allow PUD-level entries in compound testcase of hmm tests
mm/gup_test: reject wrapped user ranges
mm/page_frag: reject invalid CPUs in page_frag_test
mm/damon/core: always put unsuccessfully committed target pids
mm: page_isolation: avoid unsafe folio reads while scanning compound pages
mm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show()
selftests: mm: fix and speedup "droppable" test
mm: merge writeout into pageout
MAINTAINERS: add Hao Ge as reviewer for codetag and alloc_tag
selftests/mm: clarify alternate unmapping in compaction_test
selftests/mm: move hwpoison setup into run_test() and silence modprobe output for memory-failure category
selftests/mm: skip uffd-stress test when nr_pages_per_cpu is zero
selftests/mm: skip uffd-wp-mremap if UFFD write-protect is unsupported
selftests/mm: ensure destination is hugetlb-backed in hugetlb-mremap
selftest/mm: register existing mapping with userfaultfd in hugetlb-mremap
...
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They are used by READ_ONLY_THP_FOR_FS to handle writes to FSes without
large folio support, so that read-only THPs created in these FSes are not
seen by the FSes when the underlying fd becomes writable. Now read-only
PMD THPs only appear in a FS with large folio support and the supported
orders include PMD_ORDER.
READ_ONLY_THP_FOR_FS was using mapping->nr_thps, inode->i_writecount, and
smp_mb() to prevent writes to a read-only THP and collapsing writable
folios into a THP. In collapse_file(), mapping->nr_thps is increased,
then smp_mb(), and if inode->i_writecount > 0, collapse is stopped, while
do_dentry_open() first increases inode->i_writecount, then a full memory
fence, and if mapping->nr_thps > 0, all read-only THPs are truncated.
Now this mechanism can be removed along with READ_ONLY_THP_FOR_FS code,
since a dirty folio check has been added after try_to_unmap() in
collapse_file() to prevent dirty folios from being collapsed as clean.
Link: https://lore.kernel.org/20260517135416.1434539-7-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This flag indicates the path should be opened if it's a regular file.
This is useful to write secure programs that want to avoid being
tricked into opening device nodes with special semantics while thinking
they operate on regular files. This is a requested feature from the
uapi-group[1].
The previously introduced EFTYPE error code is returned when the path
doesn't refer to a regular file. For example, if openat2 is called on
path /dev/null with OPENAT2_REGULAR in the flag param, it will return
-EFTYPE.
When used in combination with O_CREAT, either the regular file is
created, or if the path already exists, it is opened if it's a regular
file. Otherwise, -EFTYPE is returned.
When OPENAT2_REGULAR is combined with O_DIRECTORY, -EINVAL is returned
as it doesn't make sense to open a path that is both a directory and a
regular file.
The UAPI bit lives in the upper 32 bits of open_how::flags
(((__u64)1 << 32)) so that open(2) and openat(2) -- whose @flags
argument is a C int -- cannot physically express it. This is a
structural guarantee, not a runtime mask: the bit is unrepresentable in
32 bits.
Because the rest of the VFS open path narrows to 32 bits in several
places (op->open_flag, f->f_flags, the unsigned open_flag argument of
i_op->atomic_open()), build_open_flags() translates OPENAT2_REGULAR
into a kernel-internal lower-32-bit carrier __O_REGULAR (bit 4, unused
as an O_* on every architecture) before the assignment to op->open_flag.
__O_REGULAR then rides through the existing channels exactly like
__FMODE_EXEC. do_dentry_open() strips it so it cannot leak back to
userspace via fcntl(F_GETFL).
Four BUILD_BUG_ON_MSG() invariants in build_open_flags() prevent any
future bit collision or accidental low-32 redefinition:
- VALID_OPEN_FLAGS fits in 32 bits.
- OPENAT2_REGULAR lives in the upper 32 bits.
- OPENAT2_REGULAR does not alias any open()/openat() flag.
- __O_REGULAR does not alias any user-visible flag.
[1]: https://uapi-group.org/kernel-features/#ability-to-only-open-regular-files
Christian Brauner <brauner@kernel.org> says:
Move OPENAT2_REGULAR to the upper 32 bits of open_how::flags with a
kernel-internal __O_REGULAR carrier so that open(2)/openat(2) cannot
encode the flag; add BUILD_BUG_ON_MSG() invariants and register
__O_REGULAR in the fcntl_init() allocation-uniqueness BUILD_BUG_ON()
(bit count 21 -> 22).
Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
Link: https://patch.msgid.link/20260328172314.45807-2-dorjoychy111@gmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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To get an operable version of an O_PATH file descriptor, it is possible
to use openat(fd, ".", O_DIRECTORY) for directories, but other files
currently require going through open("/proc/<pid>/fd/<nr>"), which
depends on a functioning procfs.
This patch adds the O_EMPTYPATH flag to openat(2)/openat2(2). If passed,
LOOKUP_EMPTY is set at path resolution time.
Note: This implies that you cannot rely anymore on disabling procfs from
being mounted (e.g. inside a container without procfs mounted and with
CAP_SYS_ADMIN dropped) to prevent O_PATH fds from being re-opened
read-write.
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Link: https://patch.msgid.link/20260424114611.1678641-2-jkoolstra@xs4all.nl
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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do_sys_truncate ist only used to implement ksys_truncate and the native
truncate syscalls. Merge do_sys_truncate into ksys_truncate and return
int from it as it only returns 0 or negative errnos.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260323070205.2939118-4-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Pass the flags one level down to replace the somewhat confusing small
argument, and clean up do_truncate as a result.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260323070205.2939118-3-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The "small" argument to do_sys_ftruncate indicates if > 32-bit size
should be reject, but all the arch-specific compat ftruncate64
implementations get this wrong. Merge do_sys_ftruncate and
ksys_ftruncate, replace the integer as boolean small flag with a
descriptive one about LFS semantics, and use it correctly in the
architecture-specific ftruncate64 implementations.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 3dd681d944f6 ("arm64: 32-bit (compat) applications support")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260323070205.2939118-2-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs 'struct filename' updates from Al Viro:
"[Mostly] sanitize struct filename handling"
* tag 'pull-filename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (68 commits)
sysfs(2): fs_index() argument is _not_ a pathname
alpha: switch osf_mount() to strndup_user()
ksmbd: use CLASS(filename_kernel)
mqueue: switch to CLASS(filename)
user_statfs(): switch to CLASS(filename)
statx: switch to CLASS(filename_maybe_null)
quotactl_block(): switch to CLASS(filename)
chroot(2): switch to CLASS(filename)
move_mount(2): switch to CLASS(filename_maybe_null)
namei.c: switch user pathname imports to CLASS(filename{,_flags})
namei.c: convert getname_kernel() callers to CLASS(filename_kernel)
do_f{chmod,chown,access}at(): use CLASS(filename_uflags)
do_readlinkat(): switch to CLASS(filename_flags)
do_sys_truncate(): switch to CLASS(filename)
do_utimes_path(): switch to CLASS(filename_uflags)
chdir(2): unspaghettify a bit...
do_fchownat(): unspaghettify a bit...
fspick(2): use CLASS(filename_flags)
name_to_handle_at(): use CLASS(filename_uflags)
vfs_open_tree(): use CLASS(filename_uflags)
...
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Note that failures from filename_lookup() are final - ESTALE returned
by it means that retry had been done by filename_lookup() and it failed
there.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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It accepts ERR_PTR() for name and does the right thing in that case.
That allows to simplify the logics in callers, making them trivial
to switch to CLASS(filename).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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do_file_open() will do the right thing when given ERR_PTR() as name...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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"filp" thing never made sense; seeing that there are exactly 4 callers
in the entire tree (and it's neither exported nor even declared in
linux/*/*.h), there's no point keeping that ugliness.
FWIW, the 'filp' thing did originate in OSD&I; for some reason Tanenbaum
decided to call the object representing an opened file 'struct filp',
the last letter standing for 'position'. In all Unices, Linux included,
the corresponding object had always been 'struct file'...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.
In this case we never pass LOOKUP_EMPTY, so getname_flags() is equivalent
to plain getname().
The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.
In this case we never pass LOOKUP_EMPTY, so getname_flags() is equivalent
to plain getname().
The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.
In this case we never pass LOOKUP_EMPTY, so getname_flags() is equivalent
to plain getname().
The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.
Since we have the default logics for use of LOOKUP_EMPTY (passed iff
AT_EMPTY_PATH is present in flags), just use getname_uflags() and
don't bother with setting LOOKUP_EMPTY in lookup_flags - getname_uflags()
will pass the right thing to getname_flags() and filename_lookup()
doesn't care about LOOKUP_EMPTY at all.
The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.
Since we have the default logics for use of LOOKUP_EMPTY (passed iff
AT_EMPTY_PATH is present in flags), just use getname_uflags() and
don't bother with setting LOOKUP_EMPTY in lookup_flags - getname_uflags()
will pass the right thing to getname_flags() and filename_lookup()
doesn't care about LOOKUP_EMPTY at all.
The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.
Since we have the default logics for use of LOOKUP_EMPTY (passed iff
AT_EMPTY_PATH is present in flags), just use getname_uflags() and
don't bother with setting LOOKUP_EMPTY in lookup_flags - getname_uflags()
will pass the right thing to getname_flags() and filename_lookup()
doesn't care about LOOKUP_EMPTY at all.
The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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To prepare knfsd's helper dentry_create(), move it to namei.c so that it
can access static functions within. Callers of dentry_create() can be
viewed as being mostly done with lookup, but still need to perform a few
final checks. In order to use atomic_open() we want dentry_create() to
be able to access:
- vfs_prepare_mode
- may_o_create
- atomic_open
.. all of which have static declarations.
Signed-off-by: Benjamin Coddington <bcodding@hammerspace.com>
Link: https://patch.msgid.link/42deec53a50e1676e5501f8f1e17967d47b83681.1764259052.git.bcodding@hammerspace.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull fd prepare updates from Christian Brauner:
"This adds the FD_ADD() and FD_PREPARE() primitive. They simplify the
common pattern of get_unused_fd_flags() + create file + fd_install()
that is used extensively throughout the kernel and currently requires
cumbersome cleanup paths.
FD_ADD() - For simple cases where a file is installed immediately:
fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));
if (fd < 0)
vfio_device_put_registration(device);
return fd;
FD_PREPARE() - For cases requiring access to the fd or file, or
additional work before publishing:
FD_PREPARE(fdf, O_CLOEXEC, sync_file->file);
if (fdf.err) {
fput(sync_file->file);
return fdf.err;
}
data.fence = fd_prepare_fd(fdf);
if (copy_to_user((void __user *)arg, &data, sizeof(data)))
return -EFAULT;
return fd_publish(fdf);
The primitives are centered around struct fd_prepare. FD_PREPARE()
encapsulates all allocation and cleanup logic and must be followed by
a call to fd_publish() which associates the fd with the file and
installs it into the caller's fdtable. If fd_publish() isn't called,
both are deallocated automatically. FD_ADD() is a shorthand that does
fd_publish() immediately and never exposes the struct to the caller.
I've implemented this in a way that it's compatible with the cleanup
infrastructure while also being usable separately. IOW, it's centered
around struct fd_prepare which is aliased to class_fd_prepare_t and so
we can make use of all the basica guard infrastructure"
* tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (42 commits)
io_uring: convert io_create_mock_file() to FD_PREPARE()
file: convert replace_fd() to FD_PREPARE()
vfio: convert vfio_group_ioctl_get_device_fd() to FD_ADD()
tty: convert ptm_open_peer() to FD_ADD()
ntsync: convert ntsync_obj_get_fd() to FD_PREPARE()
media: convert media_request_alloc() to FD_PREPARE()
hv: convert mshv_ioctl_create_partition() to FD_ADD()
gpio: convert linehandle_create() to FD_PREPARE()
pseries: port papr_rtas_setup_file_interface() to FD_ADD()
pseries: convert papr_platform_dump_create_handle() to FD_ADD()
spufs: convert spufs_gang_open() to FD_PREPARE()
papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE()
spufs: convert spufs_context_open() to FD_PREPARE()
net/socket: convert __sys_accept4_file() to FD_ADD()
net/socket: convert sock_map_fd() to FD_ADD()
net/kcm: convert kcm_ioctl() to FD_PREPARE()
net/handshake: convert handshake_nl_accept_doit() to FD_PREPARE()
secretmem: convert memfd_secret() to FD_ADD()
memfd: convert memfd_create() to FD_ADD()
bpf: convert bpf_token_create() to FD_PREPARE()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull directory delegations update from Christian Brauner:
"This contains the work for recall-only directory delegations for
knfsd.
Add support for simple, recallable-only directory delegations. This
was decided at the fall NFS Bakeathon where the NFS client and server
maintainers discussed how to merge directory delegation support.
The approach starts with recallable-only delegations for several reasons:
1. RFC8881 has gaps that are being addressed in RFC8881bis. In
particular, it requires directory position information for
CB_NOTIFY callbacks, which is difficult to implement properly
under Linux. The spec is being extended to allow that information
to be omitted.
2. Client-side support for CB_NOTIFY still lags. The client side
involves heuristics about when to request a delegation.
3. Early indication shows simple, recallable-only delegations can
help performance. Anna Schumaker mentioned seeing a multi-minute
speedup in xfstests runs with them enabled.
With these changes, userspace can also request a read lease on a
directory that will be recalled on conflicting accesses. This may be
useful for applications like Samba. Users can disable leases
altogether via the fs.leases-enable sysctl if needed.
VFS changes:
- Dedicated Type for Delegations
Introduce struct delegated_inode to track inodes that may have
delegations that need to be broken. This replaces the previous
approach of passing raw inode pointers through the delegation
breaking code paths, providing better type safety and clearer
semantics for the delegation machinery.
- Break parent directory delegations in open(..., O_CREAT) codepath
- Allow mkdir to wait for delegation break on parent
- Allow rmdir to wait for delegation break on parent
- Add try_break_deleg calls for parents to vfs_link(), vfs_rename(),
and vfs_unlink()
- Make vfs_create(), vfs_mknod(), and vfs_symlink() break delegations
on parent directory
- Clean up argument list for vfs_create()
- Expose delegation support to userland
Filelock changes:
- Make lease_alloc() take a flags argument
- Rework the __break_lease API to use flags
- Add struct delegated_inode
- Push the S_ISREG check down to ->setlease handlers
- Lift the ban on directory leases in generic_setlease
NFSD changes:
- Allow filecache to hold S_IFDIR files
- Allow DELEGRETURN on directories
- Wire up GET_DIR_DELEGATION handling
Fixes:
- Fix kernel-doc warnings in __fcntl_getlease
- Add needed headers for new struct delegation definition"
* tag 'vfs-6.19-rc1.directory.delegations' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
vfs: add needed headers for new struct delegation definition
filelock: __fcntl_getlease: fix kernel-doc warnings
vfs: expose delegation support to userland
nfsd: wire up GET_DIR_DELEGATION handling
nfsd: allow DELEGRETURN on directories
nfsd: allow filecache to hold S_IFDIR files
filelock: lift the ban on directory leases in generic_setlease
vfs: make vfs_symlink break delegations on parent dir
vfs: make vfs_mknod break delegations on parent directory
vfs: make vfs_create break delegations on parent directory
vfs: clean up argument list for vfs_create()
vfs: break parent dir delegations in open(..., O_CREAT) codepath
vfs: allow rmdir to wait for delegation break on parent
vfs: allow mkdir to wait for delegation break on parent
vfs: add try_break_deleg calls for parents to vfs_{link,rename,unlink}
filelock: push the S_ISREG check down to ->setlease handlers
filelock: add struct delegated_inode
filelock: rework the __break_lease API to use flags
filelock: make lease_alloc() take a flags argument
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull superblock lock guard updates from Christian Brauner:
"This starts the work of introducing guards for superblock related
locks.
Introduce super_write_guard for scoped superblock write protection.
This provides a guard-based alternative to the manual sb_start_write()
and sb_end_write() pattern, allowing the compiler to automatically
handle the cleanup"
* tag 'vfs-6.19-rc1.guards' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
xfs: use super write guard in xfs_file_ioctl()
open: use super write guard in do_ftruncate()
btrfs: use super write guard in relocating_repair_kthread()
ext4: use super write guard in write_mmp_block()
btrfs: use super write guard in sb_start_write()
btrfs: use super write guard btrfs_run_defrag_inode()
btrfs: use super write guard in btrfs_reclaim_bgs_work()
fs: add super_write_guard
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Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-13-b6efa1706cfd@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Helps out some of the asm, the routine is still a mess.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20251109125254.1288882-1-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In order to add directory delegation support, we need to break
delegations on the parent whenever there is going to be a change in the
directory.
Add a delegated_inode parameter to vfs_create. Most callers are
converted to pass in NULL, but do_mknodat() is changed to wait for a
delegation break if there is one.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-10-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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As Neil points out:
"I would be in favour of dropping the "dir" arg because it is always
d_inode(dentry->d_parent) which is stable."
...and...
"Also *every* caller of vfs_create() passes ".excl = true". So maybe we
don't need that arg at all."
Drop both arguments from vfs_create() and fix up the callers.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-9-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The current API requires a pointer to an inode pointer. It's easy for
callers to get this wrong. Add a new delegated_inode structure and use
that to pass back any inode that needs to be waited on.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-3-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Link: https://patch.msgid.link/20251104-work-guards-v1-7-5108ac78a171@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull file->f_path constification from Al Viro:
"Only one thing was modifying ->f_path of an opened file - acct(2).
Massaging that away and constifying a bunch of struct path * arguments
in functions that might be given &file->f_path ends up with the
situation where we can turn ->f_path into an anon union of const
struct path f_path and struct path __f_path, the latter modified only
in a few places in fs/{file_table,open,namei}.c, all for struct file
instances that are yet to be opened"
* tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits)
Have cc(1) catch attempts to modify ->f_path
kernel/acct.c: saner struct file treatment
configfs:get_target() - release path as soon as we grab configfs_item reference
apparmor/af_unix: constify struct path * arguments
ovl_is_real_file: constify realpath argument
ovl_sync_file(): constify path argument
ovl_lower_dir(): constify path argument
ovl_get_verity_digest(): constify path argument
ovl_validate_verity(): constify {meta,data}path arguments
ovl_ensure_verity_loaded(): constify datapath argument
ksmbd_vfs_set_init_posix_acl(): constify path argument
ksmbd_vfs_inherit_posix_acl(): constify path argument
ksmbd_vfs_kern_path_unlock(): constify path argument
ksmbd_vfs_path_lookup_locked(): root_share_path can be const struct path *
check_export(): constify path argument
export_operations->open(): constify path argument
rqst_exp_get_by_name(): constify path argument
nfs: constify path argument of __vfs_getattr()
bpf...d_path(): constify path argument
done_path_create(): constify path argument
...
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There are very few places that have cause to do that - all in core
VFS now, and all done to files that are not yet opened (or visible
to anybody else, for that matter).
Let's turn f_path into a union of struct path __f_path and const
struct path f_path. It's C, not C++ - 6.5.2.3[4] in C99 and
later explicitly allows that kind of type-punning.
That way any attempts to bypass these checks will be either very
easy to catch, or (if the bastards get sufficiently creative to
make it hard to spot with grep alone) very clearly malicious -
and still catchable with a bit of instrumentation for sparse.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... allowing any ->lookup() return value to be passed to it.
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
"A couple of small improvements for fsnotify subsystem.
The most interesting is probably Amir's change modifying the meaning
of fsnotify fmode bits (and I spell it out specifically because I know
you care about those). There's no change for the common cases of no
fsnotify watches or no permission event watches. But when there are
permission watches (either for open or for pre-content events) but no
FAN_ACCESS_PERM watch (which nobody uses in practice) we are now able
optimize away unnecessary cache loads from the read path"
* tag 'fsnotify_for_v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fsnotify: optimize FMODE_NONOTIFY_PERM for the common cases
fsnotify: merge file_set_fsnotify_mode_from_watchers() with open perm hook
samples: fix building fs-monitor on musl systems
fanotify: sanitize handle_type values when reporting fid
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull fallocate updates from Christian Brauner:
"fallocate() currently supports creating preallocated files
efficiently. However, on most filesystems fallocate() will preallocate
blocks in an unwriten state even if FALLOC_FL_ZERO_RANGE is specified.
The extent state must later be converted to a written state when the
user writes data into this range, which can trigger numerous metadata
changes and journal I/O. This may leads to significant write
amplification and performance degradation in synchronous write mode.
At the moment, the only method to avoid this is to create an empty
file and write zero data into it (for example, using 'dd' with a large
block size). However, this method is slow and consumes a considerable
amount of disk bandwidth.
Now that more and more flash-based storage devices are available it is
possible to efficiently write zeros to SSDs using the unmap write
zeroes command if the devices do not write physical zeroes to the
media.
For example, if SCSI SSDs support the UMMAP bit or NVMe SSDs support
the DEAC bit[1], the write zeroes command does not write actual data
to the device, instead, NVMe converts the zeroed range to a
deallocated state, which works fast and consumes almost no disk write
bandwidth.
This series implements the BLK_FEAT_WRITE_ZEROES_UNMAP feature and
BLK_FLAG_WRITE_ZEROES_UNMAP_DISABLED flag for SCSI, NVMe and
device-mapper drivers, and add the FALLOC_FL_WRITE_ZEROES and
STATX_ATTR_WRITE_ZEROES_UNMAP support for ext4 and raw bdev devices.
fallocate() is subsequently extended with the FALLOC_FL_WRITE_ZEROES
flag. FALLOC_FL_WRITE_ZEROES zeroes a specified file range in such a
way that subsequent writes to that range do not require further
changes to the file mapping metadata. This flag is beneficial for
subsequent pure overwriting within this range, as it can save on block
allocation and, consequently, significant metadata changes"
* tag 'vfs-6.17-rc1.fallocate' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
ext4: add FALLOC_FL_WRITE_ZEROES support
block: add FALLOC_FL_WRITE_ZEROES support
block: factor out common part in blkdev_fallocate()
fs: introduce FALLOC_FL_WRITE_ZEROES to fallocate
dm: clear unmap write zeroes limits when disabling write zeroes
scsi: sd: set max_hw_wzeroes_unmap_sectors if device supports SD_ZERO_*_UNMAP
nvmet: set WZDS and DRB if device enables unmap write zeroes operation
nvme: set max_hw_wzeroes_unmap_sectors if device supports DEAC bit
block: introduce max_{hw|user}_wzeroes_unmap_sectors to queue limits
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Create helper fsnotify_open_perm_and_set_mode() that moves the
fsnotify_open_perm() hook into file_set_fsnotify_mode_from_watchers().
This will allow some more optimizations.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250708143641.418603-2-amir73il@gmail.com
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With the development of flash-based storage devices, we can quickly
write zeros to SSDs using the WRITE_ZERO command if the devices do not
actually write physical zeroes to the media. Therefore, we can use this
command to quickly preallocate a real all-zero file with written
extents. This approach should be beneficial for subsequent pure
overwriting within this file, as it can save on block allocation and,
consequently, significant metadata changes, which should greatly improve
overwrite performance on certain filesystems.
Therefore, introduce a new operation FALLOC_FL_WRITE_ZEROES to
fallocate. This flag is used to convert a specified range of a file to
zeros by issuing a zeroing operation. Blocks should be allocated for the
regions that span holes in the file, and the entire range is converted
to written extents. If the underlying device supports the actual offload
write zeroes command, the process of zeroing out operation can be
accelerated. If it does not, we currently don't prevent the file system
from writing actual zeros to the device. This provides users with a new
method to quickly generate a zeroed file, users no longer need to write
zero data to create a file with written extents.
Users can determine whether a disk supports the unmap write zeroes
feature through querying this sysfs interface:
/sys/block/<disk>/queue/write_zeroes_unmap_max_hw_bytes
Users can also enable or disable the unmap write zeroes operation
through this sysfs interface:
/sys/block/<disk>/queue/write_zeroes_unmap_max_bytes
Finally, this flag cannot be specified in conjunction with the
FALLOC_FL_KEEP_SIZE since allocating written extents beyond file EOF is
not permitted. In addition, filesystems that always require out-of-place
writes should not support this flag since they still need to allocated
new blocks during subsequent overwrites.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/20250619111806.3546162-7-yi.zhang@huaweicloud.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/20250615003216.GB3011112@ZenIV
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Allows killing processes that are waiting for the inode lock.
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Link: https://lore.kernel.org/20250513150327.1373061-3-max.kellermann@ionos.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Allows killing processes that are waiting for the inode lock.
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Link: https://lore.kernel.org/20250513150327.1373061-2-max.kellermann@ionos.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs file handling updates from Christian Brauner:
"This contains performance improvements for struct file's new refcount
mechanism and various other performance work:
- The stock kernel transitioning the file to no refs held penalizes
the caller with an extra atomic to block any increments. For cases
where the file is highly likely to be going away this is easily
avoidable.
Add file_ref_put_close() to better handle the common case where
closing a file descriptor also operates on the last reference and
build fput_close_sync() and fput_close() on top of it. This brings
about 1% performance improvement by eliding one atomic in the
common case.
- Predict no error in close() since the vast majority of the time
system call returns 0.
- Reduce the work done in fdget_pos() by predicting that the file was
found and by explicitly comparing the reference count to one and
ignoring the dead zone"
* tag 'vfs-6.15-rc1.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: reduce work in fdget_pos()
fs: use fput_close() in path_openat()
fs: use fput_close() in filp_close()
fs: use fput_close_sync() in close()
file: add fput and file_ref_put routines optimized for use when closing a fd
fs: predict no error in close()
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"Features:
- Add CONFIG_DEBUG_VFS infrastucture:
- Catch invalid modes in open
- Use the new debug macros in inode_set_cached_link()
- Use debug-only asserts around fd allocation and install
- Place f_ref to 3rd cache line in struct file to resolve false
sharing
Cleanups:
- Start using anon_inode_getfile_fmode() helper in various places
- Don't take f_lock during SEEK_CUR if exclusion is guaranteed by
f_pos_lock
- Add unlikely() to kcmp()
- Remove legacy ->remount_fs method from ecryptfs after port to the
new mount api
- Remove invalidate_inodes() in favour of evict_inodes()
- Simplify ep_busy_loopER by removing unused argument
- Avoid mmap sem relocks when coredumping with many missing pages
- Inline getname()
- Inline new_inode_pseudo() and de-staticize alloc_inode()
- Dodge an atomic in putname if ref == 1
- Consistently deref the files table with rcu_dereference_raw()
- Dedup handling of struct filename init and refcounts bumps
- Use wq_has_sleeper() in end_dir_add()
- Drop the lock trip around I_NEW wake up in evict()
- Load the ->i_sb pointer once in inode_sb_list_{add,del}
- Predict not reaching the limit in alloc_empty_file()
- Tidy up do_sys_openat2() with likely/unlikely
- Call inode_sb_list_add() outside of inode hash lock
- Sort out fd allocation vs dup2 race commentary
- Turn page_offset() into a wrapper around folio_pos()
- Remove locking in exportfs around ->get_parent() call
- try_lookup_one_len() does not need any locks in autofs
- Fix return type of several functions from long to int in open
- Fix return type of several functions from long to int in ioctls
Fixes:
- Fix watch queue accounting mismatch"
* tag 'vfs-6.15-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
fs: sort out fd allocation vs dup2 race commentary, take 2
fs: call inode_sb_list_add() outside of inode hash lock
fs: tidy up do_sys_openat2() with likely/unlikely
fs: predict not reaching the limit in alloc_empty_file()
fs: load the ->i_sb pointer once in inode_sb_list_{add,del}
fs: drop the lock trip around I_NEW wake up in evict()
fs: use wq_has_sleeper() in end_dir_add()
VFS/autofs: try_lookup_one_len() does not need any locks
fs: dedup handling of struct filename init and refcounts bumps
fs: consistently deref the files table with rcu_dereference_raw()
exportfs: remove locking around ->get_parent() call.
fs: use debug-only asserts around fd allocation and install
fs: dodge an atomic in putname if ref == 1
vfs: Remove invalidate_inodes()
ecryptfs: remove NULL remount_fs from super_operations
watch_queue: fix pipe accounting mismatch
fs: place f_ref to 3rd cache line in struct file to resolve false sharing
epoll: simplify ep_busy_loop by removing always 0 argument
fs: Turn page_offset() into a wrapper around folio_pos()
kcmp: improve performance adding an unlikely hint to task comparisons
...
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Otherwise gcc 13 generates conditional forward jumps (aka branch
mispredict by default) for build_open_flags() being succesfull.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250320092331.1921700-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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When tracing a kernel build over refcounts seen this is a wash:
@[kprobe:filp_close]:
[0] 32195 |@@@@@@@@@@ |
[1] 164567 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
I verified vast majority of the skew comes from do_close_on_exec() which
could be changed to use a different variant instead.
Even without changing that, the 19.5% of calls which got here still can
save the extra atomic. Calls here are borderline non-existent compared
to fput (over 3.2 mln!), so they should not negatively affect
scalability.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250305123644.554845-4-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This bumps open+close rate by 1% on Sapphire Rapids by eliding one
atomic.
It would be higher if it was not for several other slowdowns of the same
nature.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250305123644.554845-3-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Vast majority of the time the system call returns 0.
Letting the compiler know shortens the routine (119 -> 116) and the fast
path.
Disasm starting at the call to __fput_sync():
before:
<+55>: call 0xffffffff816b0da0 <__fput_sync>
<+60>: lea 0x201(%rbx),%eax
<+66>: cmp $0x1,%eax
<+69>: jbe 0xffffffff816ab707 <__x64_sys_close+103>
<+71>: mov %ebx,%edx
<+73>: movslq %ebx,%rax
<+76>: and $0xfffffffd,%edx
<+79>: cmp $0xfffffdfc,%edx
<+85>: mov $0xfffffffffffffffc,%rdx
<+92>: cmove %rdx,%rax
<+96>: pop %rbx
<+97>: pop %rbp
<+98>: jmp 0xffffffff82242fa0 <__x86_return_thunk>
<+103>: mov $0xfffffffffffffffc,%rax
<+110>: jmp 0xffffffff816ab700 <__x64_sys_close+96>
<+112>: mov $0xfffffffffffffff7,%rax
<+119>: jmp 0xffffffff816ab700 <__x64_sys_close+96>
after:
<+56>: call 0xffffffff816b0da0 <__fput_sync>
<+61>: xor %eax,%eax
<+63>: test %ebp,%ebp
<+65>: jne 0xffffffff816ab6ea <__x64_sys_close+74>
<+67>: pop %rbx
<+68>: pop %rbp
<+69>: jmp 0xffffffff82242fa0 <__x86_return_thunk> # the jmp out
<+74>: lea 0x201(%rbp),%edx
<+80>: mov $0xfffffffffffffffc,%rax
<+87>: cmp $0x1,%edx
<+90>: jbe 0xffffffff816ab6e3 <__x64_sys_close+67>
<+92>: mov %ebp,%edx
<+94>: and $0xfffffffd,%edx
<+97>: cmp $0xfffffdfc,%edx
<+103>: cmovne %rbp,%rax
<+107>: jmp 0xffffffff816ab6e3 <__x64_sys_close+67>
<+109>: mov $0xfffffffffffffff7,%rax
<+116>: jmp 0xffffffff816ab6e3 <__x64_sys_close+67>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250301104356.246031-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Fix the return type of several functions from long to int to match its actu
al behavior. These functions only return int values. This change improves
type consistency across the filesystem code and aligns the function signatu
re with its existing implementation and usage.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yuichiro Tsuji <yuichtsu@amazon.com>
Link: https://lore.kernel.org/r/20250121070844.4413-2-yuichtsu@amazon.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Most pseudo files are not applicable for fsnotify events at all,
let alone to the new pre-content events.
Disable notifications to all files allocated with alloc_file_pseudo()
and enable legacy inotify events for the specific cases of pipe and
socket, which have known users of inotify events.
Pre-content events are also kept disabled for sockets and pipes.
Fixes: 20bf82a898b6 ("mm: don't allow huge faults for files with pre content watches")
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Closes: https://lore.kernel.org/linux-fsdevel/20250131121703.1e4d00a7.alex.williamson@redhat.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/linux-fsdevel/CAHk-=wi2pThSVY=zhO=ZKxViBj5QCRX-=AS2+rVknQgJnHXDFg@mail.gmail.com/
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20250203223205.861346-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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