[ Upstream commit 8344213571b2ac8caf013cfd3b37bc3467c3a893 ]

link() is documented to return EPERM when a filesystem doesn't support
the operation, return that instead.

Link: https://github.com/libfuse/libfuse/issues/925
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 7851bf649d423edd7286b292739f2eefded3d35c ]

Patch series "fs/dax: Fix ZONE_DEVICE page reference counts", v9.

Device and FS DAX pages have always maintained their own page reference
counts without following the normal rules for page reference counting.  In
particular pages are considered free when the refcount hits one rather
than zero and refcounts are not added when mapping the page.

Tracking this requires special PTE bits (PTE_DEVMAP) and a secondary
mechanism for allowing GUP to hold references on the page (see
get_dev_pagemap).  However there doesn't seem to be any reason why FS DAX
pages need their own reference counting scheme.

By treating the refcounts on these pages the same way as normal pages we
can remove a lot of special checks.  In particular pXd_trans_huge()
becomes the same as pXd_leaf(), although I haven't made that change here.
It also frees up a valuable SW define PTE bit on architectures that have
devmap PTE bits defined.

It also almost certainly allows further clean-up of the devmap managed
functions, but I have left that as a future improvment.  It also enables
support for compound ZONE_DEVICE pages which is one of my primary
motivators for doing this work.

This patch (of 20):

FS DAX requires file systems to call into the DAX layout prior to
unlinking inodes to ensure there is no ongoing DMA or other remote access
to the direct mapped page.  The fuse file system implements
fuse_dax_break_layouts() to do this which includes a comment indicating
that passing dmap_end == 0 leads to unmapping of the whole file.

However this is not true - passing dmap_end == 0 will not unmap anything
before dmap_start, and further more dax_layout_busy_page_range() will not
scan any of the range to see if there maybe ongoing DMA access to the
range.  Fix this by passing -1 for dmap_end to fuse_dax_break_layouts()
which will invalidate the entire file range to
dax_layout_busy_page_range().

Link: https://lkml.kernel.org/r/cover.8068ad144a7eea4a813670301f4d2a86a8e68ec4.1740713401.git-series.apopple@nvidia.com
Link: https://lkml.kernel.org/r/f09a34b6c40032022e4ddee6fadb7cc676f08867.1740713401.git-series.apopple@nvidia.com
Fixes: 6ae330cad6ef ("virtiofs: serialize truncate/punch_hole and dax fault path")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Fuse allows the value of a symlink to change and this property is exploited
by some filesystems (e.g. CVMFS).

It has been observed, that sometimes after changing the symlink contents,
the value is truncated to the old size.

This is caused by fuse_getattr() racing with fuse_reverse_inval_inode().
fuse_reverse_inval_inode() updates the fuse_inode's attr_version, which
results in fuse_change_attributes() exiting before updating the cached
attributes

This is okay, as the cached attributes remain invalid and the next call to
fuse_change_attributes() will likely update the inode with the correct
values.

The reason this causes problems is that cached symlinks will be
returned through page_get_link(), which truncates the symlink to
inode->i_size.  This is correct for filesystems that don't mutate
symlinks, but in this case it causes bad behavior.

The solution is to just remove this truncation.  This can cause a
regression in a filesystem that relies on supplying a symlink larger than
the file size, but this is unlikely.  If that happens we'd need to make
this behavior conditional.

Reported-by: Laura Promberger <laura.promberger@cern.ch>
Tested-by: Sam Lewis <samclewis@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://lore.kernel.org/r/20250220100258.793363-1-mszeredi@redhat.com
Reviewed-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Pull vfs d_revalidate updates from Al Viro:
 "Provide stable parent and name to ->d_revalidate() instances

  Most of the filesystem methods where we care about dentry name and
  parent have their stability guaranteed by the callers;
  ->d_revalidate() is the major exception.

  It's easy enough for callers to supply stable values for expected name
  and expected parent of the dentry being validated. That kills quite a
  bit of boilerplate in ->d_revalidate() instances, along with a bunch
  of races where they used to access ->d_name without sufficient
  precautions"

* tag 'pull-revalidate' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  9p: fix ->rename_sem exclusion
  orangefs_d_revalidate(): use stable parent inode and name passed by caller
  ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller
  nfs: fix ->d_revalidate() UAF on ->d_name accesses
  nfs{,4}_lookup_validate(): use stable parent inode passed by caller
  gfs2_drevalidate(): use stable parent inode and name passed by caller
  fuse_dentry_revalidate(): use stable parent inode and name passed by caller
  vfat_revalidate{,_ci}(): use stable parent inode passed by caller
  exfat_d_revalidate(): use stable parent inode passed by caller
  fscrypt_d_revalidate(): use stable parent inode passed by caller
  ceph_d_revalidate(): propagate stable name down into request encoding
  ceph_d_revalidate(): use stable parent inode passed by caller
  afs_d_revalidate(): use stable name and parent inode passed by caller
  Pass parent directory inode and expected name to ->d_revalidate()
  generic_ci_d_compare(): use shortname_storage
  ext4 fast_commit: make use of name_snapshot primitives
  dissolve external_name.u into separate members
  make take_dentry_name_snapshot() lockless
  dcache: back inline names with a struct-wrapped array of unsigned long
  make sure that DNAME_INLINE_LEN is a multiple of word size

Pull fuse updates from Miklos Szeredi:
 "Add support for io-uring communication between kernel and userspace
  using IORING_OP_URING_CMD (Bernd Schubert). Following features enable
  gains in performance compared to the regular interface:

   - Allow processing multiple requests with less syscall overhead

   - Combine commit of old and fetch of new fuse request

   - CPU/NUMA affinity of queues

  Patches were reviewed by several people, including Pavel Begunkov,
  io-uring co-maintainer"

* tag 'fuse-update-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: prevent disabling io-uring on active connections
  fuse: enable fuse-over-io-uring
  fuse: block request allocation until io-uring init is complete
  fuse: {io-uring} Prevent mount point hang on fuse-server termination
  fuse: Allow to queue bg requests through io-uring
  fuse: Allow to queue fg requests through io-uring
  fuse: {io-uring} Make fuse_dev_queue_{interrupt,forget} non-static
  fuse: {io-uring} Handle teardown of ring entries
  fuse: Add io-uring sqe commit and fetch support
  fuse: {io-uring} Make hash-list req unique finding functions non-static
  fuse: Add fuse-io-uring handling into fuse_copy
  fuse: Make fuse_copy non static
  fuse: {io-uring} Handle SQEs - register commands
  fuse: make args->in_args[0] to be always the header
  fuse: Add fuse-io-uring design documentation
  fuse: Move request bits
  fuse: Move fuse_get_dev to header file
  fuse: rename to fuse_dev_end_requests and make non-static

No need to mess with dget_parent() for the former; for the latter we really should
not rely upon ->d_name.name remaining stable - it's a real-life UAF.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

->d_revalidate() often needs to access dentry parent and name; that has
to be done carefully, since the locking environment varies from caller
to caller.  We are not guaranteed that dentry in question will not be
moved right under us - not unless the filesystem is such that nothing
on it ever gets renamed.

It can be dealt with, but that results in boilerplate code that isn't
even needed - the callers normally have just found the dentry via dcache
lookup and want to verify that it's in the right place; they already
have the values of ->d_parent and ->d_name stable.  There is a couple
of exceptions (overlayfs and, to less extent, ecryptfs), but for the
majority of calls that song and dance is not needed at all.

It's easier to make ecryptfs and overlayfs find and pass those values if
there's a ->d_revalidate() instance to be called, rather than doing that
in the instances.

This commit only changes the calling conventions; making use of supplied
values is left to followups.

NOTE: some instances need more than just the parent - things like CIFS
may need to build an entire path from filesystem root, so they need
more precautions than the usual boilerplate.  This series doesn't
do anything to that need - these filesystems have to keep their locking
mechanisms (rename_lock loops, use of dentry_path_raw(), private rwsem
a-la v9fs).

One thing to keep in mind when using name is that name->name will normally
point into the pathname being resolved; the filename in question occupies
name->len bytes starting at name->name, and there is NUL somewhere after it,
but it the next byte might very well be '/' rather than '\0'.  Do not
ignore name->len.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This change sets up FUSE operations to always have headers in
args.in_args[0], even for opcodes without an actual header.
This step prepares for a clean separation of payload from headers,
initially it is used by fuse-over-io-uring.

For opcodes without a header, we use a zero-sized struct as a
placeholder. This approach:
- Keeps things consistent across all FUSE operations
- Will help with payload alignment later
- Avoids future issues when header sizes change

Op codes that already have an op code specific header do not
need modification.
Op codes that have neither payload nor op code headers
are not modified either (FUSE_READLINK and FUSE_DESTROY).
FUSE_BATCH_FORGET already has the header in the right place,
but is not using fuse_copy_args - as -over-uring is currently
not handling forgets it does not matter for now, but header
separation will later need special attention for that op code.

Correct the struct fuse_args->in_args array max size.

Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Pull lsm updates from Paul Moore:

 - Improved handling of LSM "secctx" strings through lsm_context struct

   The LSM secctx string interface is from an older time when only one
   LSM was supported, migrate over to the lsm_context struct to better
   support the different LSMs we now have and make it easier to support
   new LSMs in the future.

   These changes explain the Rust, VFS, and networking changes in the
   diffstat.

 - Only build lsm_audit.c if CONFIG_SECURITY and CONFIG_AUDIT are
   enabled

   Small tweak to be a bit smarter about when we build the LSM's common
   audit helpers.

 - Check for absurdly large policies from userspace in SafeSetID

   SafeSetID policies rules are fairly small, basically just "UID:UID",
   it easy to impose a limit of KMALLOC_MAX_SIZE on policy writes which
   helps quiet a number of syzbot related issues. While work is being
   done to address the syzbot issues through other mechanisms, this is a
   trivial and relatively safe fix that we can do now.

 - Various minor improvements and cleanups

   A collection of improvements to the kernel selftests, constification
   of some function parameters, removing redundant assignments, and
   local variable renames to improve readability.

* tag 'lsm-pr-20250121' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lockdown: initialize local array before use to quiet static analysis
  safesetid: check size of policy writes
  net: corrections for security_secid_to_secctx returns
  lsm: rename variable to avoid shadowing
  lsm: constify function parameters
  security: remove redundant assignment to return variable
  lsm: Only build lsm_audit.c if CONFIG_SECURITY and CONFIG_AUDIT are set
  selftests: refactor the lsm `flags_overset_lsm_set_self_attr` test
  binder: initialize lsm_context structure
  rust: replace lsm context+len with lsm_context
  lsm: secctx provider check on release
  lsm: lsm_context in security_dentry_init_security
  lsm: use lsm_context in security_inode_getsecctx
  lsm: replace context+len with lsm_context
  lsm: ensure the correct LSM context releaser

The re-factoring of fuse_dir_open() missed the need to invalidate
directory inode page cache with open flag FOPEN_KEEP_CACHE.

Fixes: 7de64d521bf92 ("fuse: break up fuse_open_common()")
Reported-by: Prince Kumar <princer@google.com>
Closes: https://lore.kernel.org/linux-fsdevel/CAEW=TRr7CYb4LtsvQPLj-zx5Y+EYBmGfM24SuzwyDoGVNoKm7w@mail.gmail.com/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20250101130037.96680-1-amir73il@gmail.com
Reviewed-by: Bernd Schubert <bernd.schubert@fastmail.fm>
Signed-off-by: Christian Brauner <brauner@kernel.org>