[ Upstream commit fe91e078b60d1beabf5cef4a37c848457a6d2dfb ]

... 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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

While we do currently return -EFAULT in this case, it seems prudent to
follow the behaviour of other syscalls like clone3. It seems quite
unlikely that anyone depends on this error code being EFAULT, but we can
always revert this if it turns out to be an issue.

Cc: stable@vger.kernel.org # v5.6+
Fixes: fddb5d430ad9 ("open: introduce openat2(2) syscall")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20241010-extensible-structs-check_fields-v3-3-d2833dfe6edd@cyphar.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Pull 'struct fd' updates from Al Viro:
 "Just the 'struct fd' layout change, with conversion to accessor
  helpers"

* tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  add struct fd constructors, get rid of __to_fd()
  struct fd: representation change
  introduce fd_file(), convert all accessors to it.

The fallocate system call takes a mode argument, but that argument
contains a wild mix of exclusive modes and an optional flags.

Replace FALLOC_FL_SUPPORTED_MASK with FALLOC_FL_MODE_MASK, which excludes
the optional flag bit, so that we can use switch statement on the value
to easily enumerate the cases while getting the check for duplicate modes
for free.

To make this (and in the future the file system implementations) more
readable also add a symbolic name for the 0 mode used to allocate blocks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240827065123.1762168-4-hch@lst.de
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

	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 <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull misc vfs updates from Christian Brauner:
 "Features:

   - Support passing NULL along AT_EMPTY_PATH for statx().

     NULL paths with any flag value other than AT_EMPTY_PATH go the
     usual route and end up with -EFAULT to retain compatibility (Rust
     is abusing calls of the sort to detect availability of statx)

     This avoids path lookup code, lockref management, memory allocation
     and in case of NULL path userspace memory access (which can be
     quite expensive with SMAP on x86_64)

   - Don't block i_writecount during exec. Remove the
     deny_write_access() mechanism for executables

   - Relax open_by_handle_at() permissions in specific cases where we
     can prove that the caller had sufficient privileges to open a file

   - Switch timespec64 fields in struct inode to discrete integers
     freeing up 4 bytes

  Fixes:

   - Fix false positive circular locking warning in hfsplus

   - Initialize hfs_inode_info after hfs_alloc_inode() in hfs

   - Avoid accidental overflows in vfs_fallocate()

   - Don't interrupt fallocate with EINTR in tmpfs to avoid constantly
     restarting shmem_fallocate()

   - Add missing quote in comment in fs/readdir

  Cleanups:

   - Don't assign and test in an if statement in mqueue. Move the
     assignment out of the if statement

   - Reflow the logic in may_create_in_sticky()

   - Remove the usage of the deprecated ida_simple_xx() API from procfs

   - Reject FSCONFIG_CMD_CREATE_EXCL requets that depend on the new
     mount api early

   - Rename variables in copy_tree() to make it easier to understand

   - Replace WARN(down_read_trylock, ...) abuse with proper asserts in
     various places in the VFS

   - Get rid of user_path_at_empty() and drop the empty argument from
     getname_flags()

   - Check for error while copying and no path in one branch in
     getname_flags()

   - Avoid redundant smp_mb() for THP handling in do_dentry_open()

   - Rename parent_ino to d_parent_ino and make it use RCU

   - Remove unused header include in fs/readdir

   - Export in_group_capable() helper and switch f2fs and fuse over to
     it instead of open-coding the logic in both places"

* tag 'vfs-6.11.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits)
  ipc: mqueue: remove assignment from IS_ERR argument
  vfs: rename parent_ino to d_parent_ino and make it use RCU
  vfs: support statx(..., NULL, AT_EMPTY_PATH, ...)
  stat: use vfs_empty_path() helper
  fs: new helper vfs_empty_path()
  fs: reflow may_create_in_sticky()
  vfs: remove redundant smp_mb for thp handling in do_dentry_open
  fuse: Use in_group_or_capable() helper
  f2fs: Use in_group_or_capable() helper
  fs: Export in_group_or_capable()
  vfs: reorder checks in may_create_in_sticky
  hfs: fix to initialize fields of hfs_inode_info after hfs_alloc_inode()
  proc: Remove usage of the deprecated ida_simple_xx() API
  hfsplus: fix to avoid false alarm of circular locking
  Improve readability of copy_tree
  vfs: shave a branch in getname_flags
  vfs: retire user_path_at_empty and drop empty arg from getname_flags
  vfs: stop using user_path_at_empty in do_readlinkat
  tmpfs: don't interrupt fallocate with EINTR
  fs: don't block i_writecount during exec
  ...

Pull vfs fixes from Christian Brauner:
 "Misc:

   - Don't misleadingly warn during filesystem thaw operations.

     It's possible that a block device which was frozen before it was
     mounted can cause a failing thaw operation if someone concurrently
     tried to mount it while that thaw operation was issued and the
     device had already been temporarily claimed for the mount (The
     mount will of course be aborted because the device is frozen).

  netfs:

   - Fix io_uring based write-through. Make sure that the total request
     length is correctly set.

   - Fix partial writes to folio tail.

   - Remove some xarray helpers that were intended for bounce buffers
     which got defered to a later patch series.

   - Make netfs_page_mkwrite() whether folio->mapping is vallid after
     acquiring the folio lock.

   - Make netfs_page_mkrite() flush conflicting data instead of waiting.

  fsnotify:

   - Ensure that fsnotify creation events are generated before fsnotify
     open events when a file is created via ->atomic_open(). The
     ordering was broken before.

   - Ensure that no fsnotify events are generated for O_PATH file
     descriptors. While no fsnotify open events were generated, fsnotify
     close events were. Make it consistent and don't produce any"

* tag 'vfs-6.10-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  netfs: Fix netfs_page_mkwrite() to flush conflicting data, not wait
  netfs: Fix netfs_page_mkwrite() to check folio->mapping is valid
  netfs: Delete some xarray-wangling functions that aren't used
  netfs: Fix early issue of write op on partial write to folio tail
  netfs: Fix io_uring based write-through
  vfs: generate FS_CREATE before FS_OPEN when ->atomic_open used.
  fsnotify: Do not generate events for O_PATH file descriptors
  fs: don't misleadingly warn during thaw operations

opening for write performs:

if (f->f_mode & FMODE_WRITE) {
[snip]
        smp_mb();
        if (filemap_nr_thps(inode->i_mapping)) {
[snip]
        }
}

filemap_nr_thps on kernels built without CONFIG_READ_ONLY_THP_FOR
expands to 0, allowing the compiler to eliminate the entire thing, with
exception of the fence (and the branch leading there).

So happens required synchronisation between i_writecount and nr_thps
changes is already provided by the full fence coming from
get_write_access -> atomic_inc_unless_negative, thus the smp_mb instance
above can be removed regardless of CONFIG_READ_ONLY_THP_FOR.

While I updated commentary in places claiming to match the now-removed
fence, I did not try to patch them to act on the compile option.

I did not bother benchmarking it, not issuing a spurious full fence in
the fast path does not warrant justification from perf standpoint.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240624085402.493630-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

The old ftruncate() syscall, using the 32-bit off_t misses a sign
extension when called in compat mode on 64-bit architectures.  As a
result, passing a negative length accidentally succeeds in truncating
to file size between 2GiB and 4GiB.

Changing the type of the compat syscall to the signed compat_off_t
changes the behavior so it instead returns -EINVAL.

The native entry point, the truncate() syscall and the corresponding
loff_t based variants are all correct already and do not suffer
from this mistake.

Fixes: 3f6d078d4acc ("fix compat truncate/ftruncate")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

When a file is opened and created with open(..., O_CREAT) we get
both the CREATE and OPEN fsnotify events and would expect them in that
order.   For most filesystems we get them in that order because
open_last_lookups() calls fsnofify_create() and then do_open() (from
path_openat()) calls vfs_open()->do_dentry_open() which calls
fsnotify_open().

However when ->atomic_open is used, the
   do_dentry_open() -> fsnotify_open()
call happens from finish_open() which is called from the ->atomic_open
handler in lookup_open() which is called *before* open_last_lookups()
calls fsnotify_create.  So we get the "open" notification before
"create" - which is backwards.  ltp testcase inotify02 tests this and
reports the inconsistency.

This patch lifts the fsnotify_open() call out of do_dentry_open() and
places it higher up the call stack.  There are three callers of
do_dentry_open().

For vfs_open() and kernel_file_open() the fsnotify_open() is placed
directly in that caller so there should be no behavioural change.

For finish_open() there are two cases:
 - finish_open is used in ->atomic_open handlers.  For these we add a
   call to fsnotify_open() at open_last_lookups() if FMODE_OPENED is
   set - which means do_dentry_open() has been called.
 - finish_open is used in ->tmpfile() handlers.  For these a similar
   call to fsnotify_open() is added to vfs_tmpfile()

With this patch NFSv3 is restored to its previous behaviour (before
->atomic_open support was added) of generating CREATE notifications
before OPEN, and NFSv4 now has that same correct ordering that is has
not had before.  I haven't tested other filesystems.

Fixes: 7c6c5249f061 ("NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.")
Reported-by: James Clark <james.clark@arm.com>
Closes: https://lore.kernel.org/all/01c3bf2e-eb1f-4b7f-a54f-d2a05dd3d8c8@arm.com
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/171817619547.14261.975798725161704336@noble.neil.brown.name
Fixes: 7b8c9d7bb457 ("fsnotify: move fsnotify_open() hook into do_dentry_open()")
Tested-by: James Clark <james.clark@arm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240617162303.1596-2-jack@suse.cz
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>