This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Pull fsnotify updates from Jan Kara:
"A set of fixes to shutdown fsnotify subsystem before invalidating
dcache thus addressing some nasty possible races"
* tag 'fsnotify_for_v6.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fsnotify: Shutdown fsnotify before destroying sb's dcache
fsnotify: Use connector list for destroying inode marks
fsnotify: Track inode connectors for a superblock
Currently fsnotify_sb_delete() was called after we have evicted
superblock's dcache and inode cache. This was done mainly so that we
iterate as few inodes as possible when removing inode marks. However, as
Jakub reported, this is problematic because for some filesystems
encoding of file handles uses sb->s_root which gets cleared as part of
dcache eviction. And either delayed fsnotify events or reading fdinfo
for fsnotify group with marks on fs being unmounted may trigger encoding
of file handles during unmount. So move shutdown of fsnotify subsystem
before shrinking of dcache.
Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxgXvwumYvJm3cLDFfx-TsU3g5-yVsTiG=6i8KS48dn0mQ@mail.gmail.com/
Reported-by: Jakub Acs <acsjakub@amazon.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
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 <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://patch.msgid.link/176826402610.3490369.4378391061533403171.stgit@frogsfrogsfrogs
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull vfs fixes from Christian Brauner:
- Fix a type conversion bug in the ipc subsystem
- Fix per-dentry timeout warning in autofs
- Drop the fd conversion from sockets
- Move assert from iput_not_last() to iput()
- Fix reversed check in filesystems_freeze_callback()
- Use proper uapi types for new struct delegation definitions
* tag 'vfs-6.19-rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
vfs: use UAPI types for new struct delegation definition
mqueue: correct the type of ro to int
Revert "net/socket: convert sock_map_fd() to FD_ADD()"
autofs: fix per-dentry timeout warning
fs: assert on I_FREEING not being set in iput() and iput_not_last()
fs: PM: Fix reverse check in filesystems_freeze_callback()
Pull persistent dentry infrastructure and conversion from Al Viro:
"Some filesystems use a kinda-sorta controlled dentry refcount leak to
pin dentries of created objects in dcache (and undo it when removing
those). A reference is grabbed and not released, but it's not actually
_stored_ anywhere.
That works, but it's hard to follow and verify; among other things, we
have no way to tell _which_ of the increments is intended to be an
unpaired one. Worse, on removal we need to decide whether the
reference had already been dropped, which can be non-trivial if that
removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag
(DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set
claims responsibility for +1 in refcount.
The end result this series is aiming for:
- get these unbalanced dget() and dput() replaced with new primitives
that would, in addition to adjusting refcount, set and clear
persistency flag.
- instead of having kill_litter_super() mess with removing the
remaining "leaked" references (e.g. for all tmpfs files that hadn't
been removed prior to umount), have the regular
shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries,
dropping the corresponding reference if it had been set. After that
kill_litter_super() becomes an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many
places in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary
pieces have already gone into mainline. This chunk is finally getting
to the meat of that stuff - infrastructure and most of the conversions
to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here"
* tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
d_make_discardable(): warn if given a non-persistent dentry
kill securityfs_recursive_remove()
convert securityfs
get rid of kill_litter_super()
convert rust_binderfs
convert nfsctl
convert rpc_pipefs
convert hypfs
hypfs: swich hypfs_create_u64() to returning int
hypfs: switch hypfs_create_str() to returning int
hypfs: don't pin dentries twice
convert gadgetfs
gadgetfs: switch to simple_remove_by_name()
convert functionfs
functionfs: switch to simple_remove_by_name()
functionfs: fix the open/removal races
functionfs: need to cancel ->reset_work in ->kill_sb()
functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}()
functionfs: don't abuse ffs_data_closed() on fs shutdown
convert selinuxfs
...
The freeze_all_ptr check in filesystems_freeze_callback() introduced by
commit a3f8f86627 ("power: always freeze efivarfs") is reverse which
quite confusingly causes all file systems to be frozen when
filesystem_freeze_enabled is false.
On my systems it causes the WARN_ON_ONCE() in __set_task_frozen() to
trigger, most likely due to an attempt to freeze a file system that is
not ready for that.
Add a logical negation to the check in question to reverse it as
appropriate.
Fixes: a3f8f86627 ("power: always freeze efivarfs")
Cc: 6.18+ <stable@vger.kernel.org> # 6.18+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/12788397.O9o76ZdvQC@rafael.j.wysocki
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull writeback updates from Christian Brauner:
"Features:
- Allow file systems to increase the minimum writeback chunk size.
The relatively low minimal writeback size of 4MiB means that
written back inodes on rotational media are switched a lot. Besides
introducing additional seeks, this also can lead to extreme file
fragmentation on zoned devices when a lot of files are cached
relative to the available writeback bandwidth.
This adds a superblock field that allows the file system to
override the default size, and sets it to the zone size for zoned
XFS.
- Add logging for slow writeback when it exceeds
sysctl_hung_task_timeout_secs. This helps identify tasks waiting
for a long time and pinpoint potential issues. Recording the
starting jiffies is also useful when debugging a crashed vmcore.
- Wake up waiting tasks when finishing the writeback of a chunk
Cleanups:
- filemap_* writeback interface cleanups.
Adding filemap_fdatawrite_wbc ended up being a mistake, as all but
the original btrfs caller should be using better high level
interfaces instead.
This series removes all these low-level interfaces, switches btrfs
to a more specific interface, and cleans up other too low-level
interfaces. With this the writeback_control that is passed to the
writeback code is only initialized in three places.
- Remove __filemap_fdatawrite, __filemap_fdatawrite_range, and
filemap_fdatawrite_wbc
- Add filemap_flush_nr helper for btrfs
- Push struct writeback_control into start_delalloc_inodes in btrfs
- Rename filemap_fdatawrite_range_kick to filemap_flush_range
- Stop opencoding filemap_fdatawrite_range in 9p, ocfs2, and mm
- Make wbc_to_tag() inline and use it in fs"
* tag 'vfs-6.19-rc1.writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: Make wbc_to_tag() inline and use it in fs.
xfs: set s_min_writeback_pages for zoned file systems
writeback: allow the file system to override MIN_WRITEBACK_PAGES
writeback: cleanup writeback_chunk_size
mm: rename filemap_fdatawrite_range_kick to filemap_flush_range
mm: remove __filemap_fdatawrite_range
mm: remove filemap_fdatawrite_wbc
mm: remove __filemap_fdatawrite
mm,btrfs: add a filemap_flush_nr helper
btrfs: push struct writeback_control into start_delalloc_inodes
btrfs: use the local tmp_inode variable in start_delalloc_inodes
ocfs2: don't opencode filemap_fdatawrite_range in ocfs2_journal_submit_inode_data_buffers
9p: don't opencode filemap_fdatawrite_range in v9fs_mmap_vm_close
mm: don't opencode filemap_fdatawrite_range in filemap_invalidate_inode
writeback: Add logging for slow writeback (exceeds sysctl_hung_task_timeout_secs)
writeback: Wake up waiting tasks when finishing the writeback of a chunk.
The relatively low minimal writeback size of 4MiB means that written back
inodes on rotational media are switched a lot. Besides introducing
additional seeks, this also can lead to extreme file fragmentation on
zoned devices when a lot of files are cached relative to the available
writeback bandwidth.
Add a superblock field that allows the file system to override the
default size.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20251017034611.651385-3-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull vfs mount updates from Al Viro:
"Several piles this cycle, this mount-related one being the largest and
trickiest:
- saner handling of guards in fs/namespace.c, getting rid of
needlessly strong locking in some of the users
- lock_mount() calling conventions change - have it set the
environment for attaching to given location, storing the results in
caller-supplied object, without altering the passed struct path.
Make unlock_mount() called as __cleanup for those objects. It's not
exactly guard(), but similar to it
- MNT_WRITE_HOLD done right.
mnt_hold_writers() does *not* mess with ->mnt_flags anymore, so
insertion of a new mount into ->s_mounts of underlying superblock
does not, in itself, expose ->mnt_flags of that mount to concurrent
modifications
- getting rid of pathological cases when umount() spends quadratic
time removing the victims from propagation graph - part of that had
been dealt with last cycle, this should finish it
- a bunch of stuff constified
- assorted cleanups
* tag 'pull-mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
constify {__,}mnt_is_readonly()
WRITE_HOLD machinery: no need for to bump mount_lock seqcount
struct mount: relocate MNT_WRITE_HOLD bit
preparations to taking MNT_WRITE_HOLD out of ->mnt_flags
setup_mnt(): primitive for connecting a mount to filesystem
simplify the callers of mnt_unhold_writers()
copy_mnt_ns(): use guards
copy_mnt_ns(): use the regular mechanism for freeing empty mnt_ns on failure
open_detached_copy(): separate creation of namespace into helper
open_detached_copy(): don't bother with mount_lock_hash()
path_has_submounts(): use guard(mount_locked_reader)
fs/namespace.c: sanitize descriptions for {__,}lookup_mnt()
ecryptfs: get rid of pointless mount references in ecryptfs dentries
umount_tree(): take all victims out of propagation graph at once
do_mount(): use __free(path_put)
do_move_mount_old(): use __free(path_put)
constify can_move_mount_beneath() arguments
path_umount(): constify struct path argument
may_copy_tree(), __do_loopback(): constify struct path argument
path_mount(): constify struct path argument
...
Pull vfs workqueue updates from Christian Brauner:
"This contains various workqueue changes affecting the filesystem
layer.
Currently if a user enqueue a work item using schedule_delayed_work()
the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies
to schedule_work() that is using system_wq and queue_work(), that
makes use again of WORK_CPU_UNBOUND.
This replaces the use of system_wq and system_unbound_wq. system_wq is
a per-CPU workqueue which isn't very obvious from the name and
system_unbound_wq is to be used when locality is not required.
So this renames system_wq to system_percpu_wq, and system_unbound_wq
to system_dfl_wq.
This also adds a new WQ_PERCPU flag to allow the fs subsystem users to
explicitly request the use of per-CPU behavior. Both WQ_UNBOUND and
WQ_PERCPU flags coexist for one release cycle to allow callers to
transition their calls. WQ_UNBOUND will be removed in a next release
cycle"
* tag 'vfs-6.18-rc1.workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: WQ_PERCPU added to alloc_workqueue users
fs: replace use of system_wq with system_percpu_wq
fs: replace use of system_unbound_wq with system_dfl_wq
Pull vfs mount updates from Christian Brauner:
"This contains some work around mount api handling:
- Output the warning message for mnt_too_revealing() triggered during
fsmount() to the fscontext log. This makes it possible for the
mount tool to output appropriate warnings on the command line.
For example, with the newest fsopen()-based mount(8) from
util-linux, the error messages now look like:
# mount -t proc proc /tmp
mount: /tmp: fsmount() failed: VFS: Mount too revealing.
dmesg(1) may have more information after failed mount system call.
- Do not consume fscontext log entries when returning -EMSGSIZE
Userspace generally expects APIs that return -EMSGSIZE to allow for
them to adjust their buffer size and retry the operation.
However, the fscontext log would previously clear the message even
in the -EMSGSIZE case.
Given that it is very cheap for us to check whether the buffer is
too small before we remove the message from the ring buffer, let's
just do that instead.
- Drop an unused argument from do_remount()"
* tag 'vfs-6.18-rc1.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
vfs: fs/namespace.c: remove ms_flags argument from do_remount
selftests/filesystems: add basic fscontext log tests
fscontext: do not consume log entries when returning -EMSGSIZE
vfs: output mount_too_revealing() errors to fscontext
docs/vfs: Remove mentions to the old mount API helpers
fscontext: add custom-prefix log helpers
fs: Remove mount_bdev
fs: Remove mount_nodev
Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.
This lack of consistentcy cannot be addressed without refactoring the API.
alloc_workqueue() treats all queues as per-CPU by default, while unbound
workqueues must opt-in via WQ_UNBOUND.
This default is suboptimal: most workloads benefit from unbound queues,
allowing the scheduler to place worker threads where they’re needed and
reducing noise when CPUs are isolated.
This patch adds a new WQ_PERCPU flag to all the fs subsystem users to
explicitly request the use of the per-CPU behavior. Both flags coexist
for one release cycle to allow callers to transition their calls.
Once migration is complete, WQ_UNBOUND can be removed and unbound will
become the implicit default.
With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU.
All existing users have been updated accordingly.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Link: https://lore.kernel.org/20250916082906.77439-4-marco.crivellari@suse.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
We have an unpleasant wart in accessibility rules for struct mount. There
are per-superblock lists of mounts, used by sb_prepare_remount_readonly()
to check if any of those is currently claimed for write access and to
block further attempts to get write access on those until we are done.
As soon as it is attached to a filesystem, mount becomes reachable
via that list. Only sb_prepare_remount_readonly() traverses it and
it only accesses a few members of struct mount. Unfortunately,
->mnt_flags is one of those and it is modified - MNT_WRITE_HOLD set
and then cleared. It is done under mount_lock, so from the locking
rules POV everything's fine.
However, it has easily overlooked implications - once mount has been
attached to a filesystem, it has to be treated as globally visible.
In particular, initializing ->mnt_flags *must* be done either prior
to that point or under mount_lock. All other members are still
private at that point.
Life gets simpler if we move that bit (and that's *all* that can get
touched by access via this list) out of ->mnt_flags. It's not even
hard to do - currently the list is implemented as list_head one,
anchored in super_block->s_mounts and linked via mount->mnt_instance.
As the first step, switch it to hlist-like open-coded structure -
address of the first mount in the set is stored in ->s_mounts
and ->mnt_instance replaced with ->mnt_next_for_sb and ->mnt_pprev_for_sb -
the former either NULL or pointing to the next mount in set, the
latter - address of either ->s_mounts or ->mnt_next_for_sb in the
previous element of the set.
In the next commit we'll steal the LSB of ->mnt_pprev_for_sb as
replacement for MNT_WRITE_HOLD.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull superblock callback update from Christian Brauner:
"Currently all filesystems which implement super_operations::shutdown()
can not afford losing a device.
Thus fs_bdev_mark_dead() will just call the ->shutdown() callback for
the involved filesystem.
But it will no longer be the case, as multi-device filesystems like
btrfs can handle certain device loss without the need to shutdown the
whole filesystem.
To allow those multi-device filesystems to be integrated to use
fs_holder_ops:
- Add a new super_operations::remove_bdev() callback
- Try ->remove_bdev() callback first inside fs_bdev_mark_dead().
If the callback returned 0, meaning the fs can handling the device
loss, then exit without doing anything else.
If there is no such callback or the callback returned non-zero
value, continue to shutdown the filesystem as usual.
This means the new remove_bdev() should only do the check on whether
the operation can continue, and if so do the fs specific handlings.
The shutdown handling should still be handled by the existing
->shutdown() callback.
For all existing filesystems with shutdown callback, there is no
change to the code nor behavior.
Btrfs is going to implement both the ->remove_bdev() and ->shutdown()
callbacks soon"
* tag 'vfs-6.17-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: add a new remove_bdev() callback
Currently all filesystems which implement super_operations::shutdown()
can not afford losing a device.
Thus fs_bdev_mark_dead() will just call the ->shutdown() callback for the
involved filesystem.
But it will no longer be the case, as multi-device filesystems like
btrfs and bcachefs can handle certain device loss without the need to
shutdown the whole filesystem.
To allow those multi-device filesystems to be integrated to use
fs_holder_ops:
- Add a new super_operations::remove_bdev() callback
- Try ->remove_bdev() callback first inside fs_bdev_mark_dead()
If the callback returned 0, meaning the fs can handling the device
loss, then exit without doing anything else.
If there is no such callback or the callback returned non-zero value,
continue to shutdown the filesystem as usual.
This means the new remove_bdev() should only do the check on whether the
operation can continue, and if so do the fs specific handlings.
The shutdown handling should still be handled by the existing
->shutdown() callback.
For all existing filesystems with shutdown callback, there is no change
to the code nor behavior.
Btrfs is going to implement both the ->remove_bdev() and ->shutdown()
callbacks soon.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Link: https://lore.kernel.org/09909fcff7f2763cc037fec97ac2482bdc0a12cb.1752470276.git.wqu@suse.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull automount updates from Al Viro:
"Automount wart removal
A bunch of odd boilerplate gone from instances - the reason for
those was the need to protect the yet-to-be-attched mount from
mark_mounts_for_expiry() deciding to take it out.
But that's easy to detect and take care of in mark_mounts_for_expiry()
itself; no need to have every instance simulate mount being busy by
grabbing an extra reference to it, with finish_automount() undoing
that once it attaches that mount.
Should've done it that way from the very beginning... This is a
flagday change, thankfully there are very few instances.
vfs_submount() is gone - its sole remaining user (trace_automount)
had been switched to saner primitives"
* tag 'pull-automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
kill vfs_submount()
saner calling conventions for ->d_automount()
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