Pull misc vfs updates from Christian Brauner:
 "Features:

   - Reduce pipe->mutex contention by pre-allocating pages outside the
     lock in anon_pipe_write().

     anon_pipe_write() called alloc_page() once per page while holding
     pipe->mutex. The allocation can sleep doing direct reclaim and runs
     memcg charging, which extends the critical section and stalls any
     concurrent reader on the same mutex. Now up to 8 pages are
     pre-allocated before the mutex is taken, leftovers are recycled
     into the per-pipe tmp_page[] cache before unlock, and any remainder
     is released after unlock, keeping the allocator out of the critical
     section on both sides. On a writers x readers sweep with 64KB
     writes against a 1 MB pipe throughput improves 6-28% and average
     write latency drops 5-22%; under memory pressure - when the cost of
     holding the mutex across reclaim is highest - throughput improves
     21-48% and latency drops 17-33%. The microbenchmark is added to
     selftests.

   - uaccess/sockptr: fix the ignored_trailing logic in
     copy_struct_to_user() to behave as documented and the usize check
     in copy_struct_from_sockptr() for user pointers, and add
     copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr()
     helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC).

   - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real
     inode backing a dentry via d_real_inode(). On overlayfs the inode
     attached to the dentry doesn't carry the underlying device
     information; this is used by the filesystem restriction BPF program
     that was merged into systemd.

   - docs: add guidelines for submitting new filesystems, motivated by
     the maintenance burden abandoned and untestable filesystems impose
     on VFS developers, blocking infrastructure work like folio
     conversions and iomap migration.

  Fixes:

   - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
     and drop the now-redundant assignments in callers. This began as a
     one-line dma-buf fix for a path_noexec() warning; a pseudo
     filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo()
     callers were audited: the only visible effect is on dma-buf where
     SB_I_NOEXEC silences the warning.

   - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs,
     qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a
     device with a sector size > PAGE_SIZE crashed roughly half of them;
     the rest had the same missing error handling pattern. Plus a
     follow-up releasing the superblock buffer_head when setting the
     minix v3 block size fails.

   - mount: honour SB_NOUSER in the new mount API.

   - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by
     switching the process-group paths of send_sigio() and send_sigurg()
     from read_lock(&tasklist_lock) to RCU, matching the single-PID
     path.

   - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing
     delegated NFS mounts (fsopen() in a container with the mount
     performed by a privileged daemon) that broke when non-init
     s_user_ns was tied to FS_USERNS_MOUNT.

   - selftests/namespaces: fix a hang in nsid_test where an unreaped
     grandchild kept the TAP pipe write-end open, a waitpid(-1) race in
     listns_efault_test, and a false FAIL on kernels without listns()
     where the tests should SKIP.

   - filelock: fix the break_lease() stub signature for
     CONFIG_FILE_LOCKING=n.

   - init/initramfs_test: wait for the async initramfs unpacking before
     running; the test and do_populate_rootfs() share the parser state.

   - fs/coredump: reduce redundant log noise in
     validate_coredump_safety().

   - iomap: pass the correct length to fserror_report_io() in
     __iomap_write_begin().

   - backing-file: fix the backing_file_open() kerneldoc.

  Cleanups:

   - initramfs: refactor the cpio hex header parsing to use hex2bin()
     instead of the hand-rolled simple_strntoul() which is reverted, and
     extend the initramfs KUnit tests to cover header fields with 0x
     prefixes.

   - Replace __get_free_pages() and friends with kmalloc()/kzalloc()
     across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2,
     isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the
     do_mounts init code - part of the larger work of replacing page
     allocator calls with kmalloc().

   - Use clear_and_wake_up_bit() in unlock_buffer() and
     journal_end_buffer_io_sync() instead of open-coding the sequence.

   - Drop unused VFS exports: unexport drop_super_exclusive(), remove
     start_removing_user_path_at(), and fold __start_removing_path()
     into start_removing_path().

   - fs/read_write: narrow the __kernel_write() export with
     EXPORT_SYMBOL_FOR_MODULES().

   - vfs: uapi: retire octal and hex constants in favor of (1 << n) for
     the O_ flags. Finding a free bit for a new flag across the
     architectures was needlessly hard with the mixed bases.

   - dcache: add extra sanity checks of dead dentries in dentry_free()
     via a new DENTRY_WARN_ONCE() that also prints d_flags.

   - iov_iter: use kmemdup_array() in dup_iter() to harden the
     allocation against multiplication overflow.

   - fs/pipe: write to ->poll_usage only once.

   - vfs: remove an always-taken if-branch in find_next_fd().

   - dcache: use kmalloc_flex() for struct external_name in __d_alloc().

   - namei: use QSTR() instead of QSTR_INIT() in path_pts().

   - sync_file_range: delete dead S_ISLNK code.

   - Comment fixes: retire a stale comment in fget_task_next() and fix
     assorted spelling mistakes"

* tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits)
  backing-file: fix backing_file_open() kerneldoc parameter
  iomap: pass the correct len to fserror_report_io in __iomap_write_begin
  vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS
  filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n
  vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags
  bpf: add bpf_real_inode() kfunc
  fs/read_write: Do not export __kernel_write() to the entire world
  libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers
  libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
  mount: honour SB_NOUSER in the new mount API
  fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling
  selftests/pipe: add pipe_bench microbenchmark
  fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write
  fs: retire stale comment in fget_task_next()
  fs: fix spelling mistakes in comment
  bfs: replace get_zeroed_page() with kzalloc()
  binfmt_misc: replace __get_free_page() with kmalloc()
  configfs: replace __get_free_pages() with kzalloc()
  fs/namespace: use __getname() to allocate mntpath buffer
  fs/select: replace __get_free_page() with kmalloc()
  ...

Pull vfs casefolding updates from Christian Brauner:
 "This exposes the case folding behavior of local filesystems so that
  file servers - nfsd, ksmbd, and user space file servers - can report
  the actual behavior to clients instead of guessing.

  Filesystems report case-insensitive and case-nonpreserving behavior
  via new file_kattr flags in their fileattr_get implementations. fat,
  exfat, ntfs3, hfs, hfsplus, xfs, cifs, nfs, vboxsf, and isofs are
  wired up. Local filesystems that are not explicitly handled default to
  the usual POSIX behavior of case-sensitive and case-preserving.

  nfsd uses this to report case folding via NFSv3 PATHCONF and to
  implement the NFSv4 FATTR4_CASE_INSENSITIVE and FATTR4_CASE_PRESERVING
  attributes - both have been part of the NFS protocols for decades to
  support clients on non-POSIX systems - and ksmbd reports it via
  FS_ATTRIBUTE_INFORMATION. Exposing the information through the
  fileattr uapi covers user space file servers.

  The immediate motivation is interoperability: Windows NFS clients
  hard-require servers to report case-insensitivity for Win32
  applications to work correctly, and a client that knows the server is
  case-insensitive can avoid issuing multiple LOOKUP/READDIR requests
  searching for case variants.

  The Linux NFS client already grew support for case-insensitive shares
  years ago in support of the Hammerspace NFS server - negative dentry
  caching must be disabled (a lookup for "FILE.TXT" failing must not
  cache a negative entry when "file.txt" exists) and directory change
  invalidation must drop cached case-folded name variants. Such servers
  often operate in multi-protocol environments where a single file
  service instance caters to both NFS and SMB clients, and nfsd needs to
  report case folding properly to participate as a first-class citizen
  there.

  A follow-up series brings fixes for the initial work: the nfsd
  case-info probe now uses kernel credentials, maps -ESTALE to
  NFS3ERR_STALE, and has its cost capped across READDIR entries; the nfs
  client avoids transiently zeroed case capability bits during the probe
  and skips the pathconf probe when neither field is consumed; the
  FS_CASEFOLD_FL semantics are clarified in the UAPI header; and the
  tools UAPI headers are synced"

* tag 'vfs-7.2-rc1.casefold' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (22 commits)
  nfsd: Cap case-folding probe cost across READDIR entries
  nfsd: Map -ESTALE from case probe to NFS3ERR_STALE
  nfsd: Use kernel credentials for case-info probe
  fs: Clarify FS_CASEFOLD_FL semantics in UAPI header
  nfs: Skip pathconf probe when neither field is consumed
  nfs: Avoid transient zeroed case capability bits during probe
  tools headers UAPI: Sync case-sensitivity flags from linux/fs.h
  ksmbd: Report filesystem case sensitivity via FS_ATTRIBUTE_INFORMATION
  nfsd: Implement NFSv4 FATTR4_CASE_INSENSITIVE and FATTR4_CASE_PRESERVING
  nfsd: Report export case-folding via NFSv3 PATHCONF
  isofs: Implement fileattr_get for case sensitivity
  vboxsf: Implement fileattr_get for case sensitivity
  nfs: Implement fileattr_get for case sensitivity
  cifs: Implement fileattr_get for case sensitivity
  xfs: Report case sensitivity in fileattr_get
  hfsplus: Report case sensitivity in fileattr_get
  hfs: Implement fileattr_get for case sensitivity
  ntfs3: Implement fileattr_get for case sensitivity
  exfat: Implement fileattr_get for case sensitivity
  fat: Implement fileattr_get for case sensitivity
  ...

Pull exportfs updates from Christian Brauner:
 "This cleans up the exportfs support for block-style layouts that
  provide direct block device access: the operations for layout-based
  block device access are split out of struct export_operations into a
  separate header, ->commit_blocks() no longer takes a struct iattr
  argument, and the way support for layout-based block device access is
  detected is reworked.

  nfsd's blocklayout code also stops honoring loca_time_modify. This is
  preparation for supporting export of more than a single device per
  file system"

* tag 'vfs-7.2-rc1.exportfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  exportfs,nfsd: rework checking for layout-based block device access support
  exportfs: don't pass struct iattr to ->commit_blocks
  exportfs: split out the ops for layout-based block device access
  nfsd/blocklayout: always ignore loca_time_modify

nfsd_buffered_readdir() allocates a staging buffer with __get_free_page().

kmalloc() is a better API for such use and it also provides better
scalability and more debugging possibilities.

Replace use of __get_free_page() with kmalloc().

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260523-b4-fs-v1-7-275e36a83f0e@kernel.org
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

Pull nfsd fixes from Chuck Lever:
 "Regressions:

   - Tighten bounds checking for sunrpc cache hash tables

   - Don't report key material in the ftrace log

  Stable fix:

   - Fix lockd's implementation of the NLM TEST procedure"

* tag 'nfsd-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  lockd: fix TEST handling when not all permissions are available.
  NFSD: Report whether fh_key was actually updated
  sunrpc: prevent out-of-bounds read in __cache_seq_start()

The nfsd_ctl_fh_key_set tracepoint was introduced to capture
operator activity on the filehandle signing key. Earlier revisions
logged the key bytes verbatim; the version that landed hashes the
16 key bytes through crc32_le and stores the result.

CRC32 is a linear projection of its input rather than a one-way
function, and truncating any hash of fixed-size secret material
leaves the key recoverable under offline brute force when the
threat model includes an attacker with access to the trace ring.

The operational question the fingerprint was meant to answer is
whether a NFSD_CMD_THREADS_SET call that carries an
NFSD_A_SERVER_FH_KEY attribute actually replaced the active key or
re-installed the value already in place. Answer that question
directly: compare the incoming key bytes against the current
nn->fh_key inside nfsd_nl_fh_key_set() and surface a single bit to
the tracepoint. The event now prints "updated" when the stored
key changed and "unmodified" otherwise. A first set that fails
kmalloc reports "unmodified" because no key was installed.

Reported-by: jaeyeong <fin@spl.team>
Fixes: 62346217fd72 ("NFSD: Add a key for signing filehandles")
Cc: Benjamin Coddington <bcodding@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull nfsd fixes from Chuck Lever:
 "Fixes for this release:
   - Correctness fix for the new sunrpc cache netlink protocol

  Marked for stable:
   - Correctness fixes for delegated attributes
   - Prevent an infinite loop when revoking layouts"

* tag 'nfsd-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  NFSD: Fix infinite loop in layout state revocation
  sunrpc: start cache request seqno at 1 to fix netlink GET_REQS
  nfsd: update mtime/ctime on COPY in presence of delegated attributes
  nfsd: update mtime/ctime on CLONE in presense of delegated attributes
  nfsd: fix file change detection in CB_GETATTR
  nfsd: fix GET_DIR_DELEGATION when VFS leases are disabled

NFSv4 READDIR carries a per-entry attrmask. When the attrmask
includes FATTR4_CASE_INSENSITIVE or FATTR4_CASE_PRESERVING,
nfsd4_encode_fattr4() resolves each non-directory child's case
attributes by calling nfsd_get_case_info(), which dget_parent()s
back to the directory being read and re-runs the cred swap and LSM
probe per child. The encoder amplifies a single answer into one
prepare_kernel_cred() allocation, two LSM hooks, and one put_cred()
RCU callback for every non-directory entry.

No mainstream NFSv4 client has been observed to populate a READDIR
attrmask with these attributes; the Linux client queries them only
via SERVER_CAPS at mount time. The exposure is therefore to test
clients exploring corner cases and to hostile clients that submit
an attrmask designed to multiply server work by rd_dircount.

Probe the directory being read once and cache the result on
struct nfsd4_readdir for use by every non-directory child. The
probe targets the readdir filehandle's dentry, which is held for
the duration of the request, rather than dget_parent() of a
child's locklessly-acquired dentry; the latter could be moved out
of the directory by a concurrent rename and report attributes
from an unrelated parent. Directory entries continue to be
queried individually, because casefold-capable filesystems (ext4,
f2fs) report case state per directory. The other callers of
nfsd4_encode_fattr4() (single GETATTR, the buffer wrapper) pass
NULL for the cache pointer and behave as before.

Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260507-case-sensitivity-v14-0-e62cc8200435@oracle.com?part=14
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260515153515.362266-8-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

The PATHCONF switch in nfsd3_proc_pathconf() recognizes -EOPNOTSUPP
(filesystem does not expose case state) and maps -EACCES / -EPERM to
nfserr_stale, but lets every other errno fall through to
nfserr_serverfault. -ESTALE escapes the same way even though RFC 1813
lists NFS3ERR_STALE as a permitted PATHCONF status, so a probe of an
NFS-backed re-export whose parent dentry has been invalidated returns
SERVERFAULT and tells the client the server is broken when the handle
itself simply went stale.

Add an explicit -ESTALE arm that maps to nfserr_stale.

Fixes: a8de9c3b40e4 ("nfsd: Report export case-folding via NFSv3 PATHCONF")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260507-case-sensitivity-v14-0-e62cc8200435@oracle.com?part=13
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260515153515.362266-7-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

nfsd_get_case_info() takes prepare_creds() and overrides fsuid/fsgid
to GLOBAL_ROOT, intending to escape per-client policy on the parent
directory. prepare_creds() copies the calling task's full credential,
including the LSM security label, so only the DAC identity is
neutralized. With labeled NFS, where the active LSM context has been
mapped to the client, security_inode_file_getattr() can still deny the
probe with -EACCES even though the case-folding property the caller
wants is structural and identical for every client. The docblock
already states the intent ("the probe runs with kernel credentials"),
which the implementation does not deliver.

prepare_kernel_cred(&init_task) constructs a credential from
init_task's identity and security label, the kernel's own unconfined
context. Use it instead and drop the redundant fsuid/fsgid overrides
that init_task already supplies. The probe now matches the docblock,
LSM denials on the parent disappear, and the call sites that map an
unexpected error to NFS3ERR_SERVERFAULT or fail an NFSv4 GETATTR
outright stop seeing -EACCES from this path.

Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260507-case-sensitivity-v14-0-e62cc8200435@oracle.com?part=14
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260515153515.362266-6-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>