linux.git/fs/ioctl.c, branch v6.17

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

Merge tag 'vfs-6.16-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-05-26T16:33:44+00:00

Pull vfs freezing updates from Christian Brauner:
 "This contains various filesystem freezing related work for this cycle:

   - Allow the power subsystem to support filesystem freeze for suspend
     and hibernate.

     Now all the pieces are in place to actually allow the power
     subsystem to freeze/thaw filesystems during suspend/resume.
     Filesystems are only frozen and thawed if the power subsystem does
     actually own the freeze.

     If the filesystem is already frozen by the time we've frozen all
     userspace processes we don't care to freeze it again. That's
     userspace's job once the process resumes. We only actually freeze
     filesystems if we absolutely have to and we ignore other failures
     to freeze.

     We could bubble up errors and fail suspend/resume if the error
     isn't EBUSY (aka it's already frozen) but I don't think that this
     is worth it. Filesystem freezing during suspend/resume is
     best-effort. If the user has 500 ext4 filesystems mounted and 4
     fail to freeze for whatever reason then we simply skip them.

     What we have now is already a big improvement and let's see how we
     fare with it before making our lives even harder (and uglier) than
     we have to.

   - Allow efivars to support freeze and thaw

     Allow efivarfs to partake to resync variable state during system
     hibernation and suspend. Add freeze/thaw support.

     This is a pretty straightforward implementation. We simply add
     regular freeze/thaw support for both userspace and the kernel.
     efivars is the first pseudofilesystem that adds support for
     filesystem freezing and thawing.

     The simplicity comes from the fact that we simply always resync
     variable state after efivarfs has been frozen. It doesn't matter
     whether that's because of suspend, userspace initiated freeze or
     hibernation. Efivars is simple enough that it doesn't matter that
     we walk all dentries. There are no directories and there aren't
     insane amounts of entries and both freeze/thaw are already
     heavy-handed operations. If userspace initiated a freeze/thaw cycle
     they would need CAP_SYS_ADMIN in the initial user namespace (as
     that's where efivarfs is mounted) so it can't be triggered by
     random userspace. IOW, we really really don't care"

* tag 'vfs-6.16-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  f2fs: fix freezing filesystem during resize
  kernfs: add warning about implementing freeze/thaw
  efivarfs: support freeze/thaw
  power: freeze filesystems during suspend/resume
  libfs: export find_next_child()
  super: add filesystem freezing helpers for suspend and hibernate
  gfs2: pass through holder from the VFS for freeze/thaw
  super: use common iterator (Part 2)
  super: use a common iterator (Part 1)
  super: skip dying superblocks early
  super: simplify user_get_super()
  super: remove pointless s_root checks
  fs: allow all writers to be frozen
  locking/percpu-rwsem: add freezable alternative to down_read

super: add filesystem freezing helpers for suspend and hibernate

2025-05-09T10:41:02+00:00

Allow the power subsystem to support filesystem freeze for
suspend and hibernate.

For some kernel subsystems it is paramount that they are guaranteed that
they are the owner of the freeze to avoid any risk of deadlocks. This is
the case for the power subsystem. Enable it to recognize whether it did
actually freeze the filesystem.

If userspace has 10 filesystems and suspend/hibernate manges to freeze 5
and then fails on the 6th for whatever odd reason (current or future)
then power needs to undo the freeze of the first 5 filesystems. It can't
just walk the list again because while it's unlikely that a new
filesystem got added in the meantime it still cannot tell which
filesystems the power subsystem actually managed to get a freeze
reference count on that needs to be dropped during thaw.

There's various ways out of this ugliness. For example, record the
filesystems the power subsystem managed to freeze on a temporary list in
the callbacks and then walk that list backwards during thaw to undo the
freezing or make sure that the power subsystem just actually exclusively
freezes things it can freeze and marking such filesystems as being owned
by power for the duration of the suspend or resume cycle. I opted for
the latter as that seemed the clean thing to do even if it means more
code changes.

If hibernation races with filesystem freezing (e.g. DM reconfiguration),
then hibernation need not freeze a filesystem because it's already
frozen but userspace may thaw the filesystem before hibernation actually
happens.

If the race happens the other way around, DM reconfiguration may
unexpectedly fail with EBUSY.

So allow FREEZE_EXCL to nest with other holders. An exclusive freezer
cannot be undone by any of the other concurrent freezers.

Link: https://lore.kernel.org/r/20250329-work-freeze-v2-6-a47af37ecc3d@kernel.org
Reviewed-by: Jan Kara 
Signed-off-by: Christian Brauner

fs: add S_ANON_INODE

2025-04-21T11:20:14+00:00

This makes it easy to detect proper anonymous inodes and to ensure that
we can detect them in codepaths such as readahead().

Readahead on anonymous inodes didn't work because they didn't have a
proper mode. Now that they have we need to retain EINVAL being returned
otherwise LTP will fail.

We also need to ensure that ioctls aren't simply fired like they are for
regular files so things like inotify inodes continue to correctly call
their own ioctl handlers as in [1].

Reported-by: Xilin Wu 
Link: https://lore.kernel.org/3A9139D5CD543962+89831381-31b9-4392-87ec-a84a5b3507d8@radxa.com [1]
Link: https://lore.kernel.org/7a1a7076-ff6b-4cb0-94e7-7218a0a44028@sirena.org.uk
Signed-off-by: Christian Brauner

ioctl: Fix return type of several functions from long to int

2025-02-21T09:25:32+00:00

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 
Signed-off-by: Yuichiro Tsuji 
Link: https://lore.kernel.org/r/20250121070844.4413-3-yuichtsu@amazon.com
Signed-off-by: Christian Brauner

fdget(), trivial conversions

2024-11-03T06:28:06+00:00

fdget() is the first thing done in scope, all matching fdput() are
immediately followed by leaving the scope.

Reviewed-by: Christian Brauner 
Signed-off-by: Al Viro

introduce fd_file(), convert all accessors to it.

2024-08-13T02:00:43+00:00

	For any changes of struct fd representation we need to
turn existing accesses to fields into calls of wrappers.
Accesses to struct fd::flags are very few (3 in linux/file.h,
1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in
explicit initializers).
	Those can be dealt with in the commit converting to
new layout; accesses to struct fd::file are too many for that.
	This commit converts (almost) all of f.file to
fd_file(f).  It's not entirely mechanical ('file' is used as
a member name more than just in struct fd) and it does not
even attempt to distinguish the uses in pointer context from
those in boolean context; the latter will be eventually turned
into a separate helper (fd_empty()).

	NOTE: mass conversion to fd_empty(), tempting as it
might be, is a bad idea; better do that piecewise in commit
that convert from fdget...() to CLASS(...).

[conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c
caught by git; fs/stat.c one got caught by git grep]
[fs/xattr.c conflict]

Reviewed-by: Christian Brauner 
Signed-off-by: Al Viro

fs/ioctl: Add a comment to keep the logic in sync with LSM policies

2024-05-13T04:58:35+00:00

Landlock's IOCTL support needs to partially replicate the list of
IOCTLs from do_vfs_ioctl().  The list of commands implemented in
do_vfs_ioctl() should be kept in sync with Landlock's IOCTL policies.

Suggested-by: Paul Moore 
Suggested-by: Mickaël Salaün 
Signed-off-by: Günther Noack 
Link: https://lore.kernel.org/r/20240419161122.2023765-12-gnoack@google.com
Signed-off-by: Mickaël Salaün

fs: Return ENOTTY directly if FS_IOC_GETUUID or FS_IOC_GETFSSYSFSPATH fail

2024-04-09T10:03:49+00:00

These IOCTL commands should be implemented by setting attributes on the
superblock, rather than in the IOCTL hooks in struct file_operations.

By returning -ENOTTY instead of -ENOIOCTLCMD, we instruct the fs/ioctl.c
logic to return -ENOTTY immediately, rather than attempting to call
f_op->unlocked_ioctl() or f_op->compat_ioctl() as a fallback.

Why this is safe:

Before this change, fs/ioctl.c would unsuccessfully attempt calling the
IOCTL hooks, and then return -ENOTTY.  By returning -ENOTTY directly, we
return the same error code immediately, but save ourselves the fallback
attempt.

Motivation:

This simplifies the logic for these IOCTL commands and lets us reason about
the side effects of these IOCTLs more easily.  It will be possible to
permit these IOCTLs under LSM IOCTL policies, without having to worry about
them getting dispatched to problematic device drivers (which sometimes do
work before looking at the IOCTL command number).

Link: https://lore.kernel.org/all/cnwpkeovzbumhprco7q2c2y6zxzmxfpwpwe3tyy6c3gg2szgqd@vfzjaw5v5imr/
Cc: Kent Overstreet 
Cc: Christian Brauner 
Cc: Jan Kara 
Cc: Dave Chinner 
Cc: Darrick J. Wong 
Cc: Theodore Ts'o 
Cc: Josef Bacik 
Signed-off-by: Günther Noack 
Link: https://lore.kernel.org/r/20240405214040.101396-2-gnoack@google.com
Acked-by: Kent Overstreet 
Signed-off-by: Christian Brauner

fs: add FS_IOC_GETFSSYSFSPATH

2024-02-12T12:13:59+00:00

Add a new ioctl for getting the sysfs name of a filesystem - the path
under /sys/fs.

This is going to let us standardize exporting data from sysfs across
filesystems, e.g. time stats.

The returned path will always be of the form "$FSTYP/$SYSFS_IDENTIFIER",
where the sysfs identifier may be a UUID (for bcachefs) or a device name
(xfs).

Cc: Christian Brauner 
Cc: Jan Kara 
Cc: Dave Chinner 
Cc: Darrick J. Wong 
Cc: Theodore Ts'o 
Cc: Josef Bacik 
Signed-off-by: Kent Overstreet 
Link: https://lore.kernel.org/r/20240207025624.1019754-6-kent.overstreet@linux.dev
Signed-off-by: Christian Brauner