Merge tag 'vfs-7.2-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - vfs: Preserve the ACL_DONT_CACHE state in forget_cached_acl().

   ACL_DONT_CACHE is meant to be a permanent opt-out from ACL caching
   which FUSE relies on for servers that don't negotiate FUSE_POSIX_ACL.
   The helper replaced it with ACL_NOT_CACHED, silently re-enabling the
   cache, and as fuse doesn't invalidate the cache for such servers a
   properly timed get_acl() returned stale ACLs. Comes with a fuse
   selftest reproducing this.

 - pidfs:

     - Preserve PIDFD_THREAD when a thread pidfd is reopened via
       open_by_handle_at(). PIDFD_THREAD shares the O_EXCL bit which
       do_dentry_open() strips after the flags have been validated, so
       the reopened pidfd silently became a process pidfd. Comes with a
       selftest.

     - Add a pidfs_dentry_open() helper so the regular pidfd allocation
       path and the file handle path share the code that forces O_RDWR
       and reapplies the pidfd flags that do_dentry_open() strips.

     - Handle FS_IOC32_GETVERSION in the compat ioctl path.

     - Make pidfs_ino_lock static.

 - iomap:

     - Fix the block range calculation in ifs_clear_range_dirty() so a
       partial clear doesn't drop the dirty state of blocks the range
       only partially covers.

     - Support invalidating partial folios so a partial truncate or hole
       punch with blocksize < foliosize doesn't leave stale dirty bits
       behind.

     - Only set did_zero when iomap_zero_iter() actually zeroed
       something.

     - Guard ifs_set_range_dirty() and ifs_set_range_uptodate() against
       zero-length ranges where the unsigned last-block calculation
       underflows and bitmap_set() writes far beyond the ifs->state
       allocation.

     - Don't merge ioends with different io_private values as the merge
       could leak or corrupt the private data of the individual ioends.

 - exec:

     - Raise bprm->have_execfd only once the binfmt_misc interpreter has
       actually been opened. The flag was set as soon as a matching 'O'
       or 'C' entry was found. If the interpreter open failed with
       ENOEXEC the exec fell through to the next binary format with
       have_execfd raised but no executable staged and begin_new_exec()
       NULL derefed past the point of no return.

     - Fix an unsigned loop counter wrap in transfer_args_to_stack() on
       nommu. An overlong argument or environment string pushes bprm->p
       below PAGE_SIZE, the stop index becomes zero, and the loop never
       terminates, wrapping its counter and copying garbage from in
       front of the page array into the new process stack.

     - Make binfmt_elf_fdpic only honour the first PT_INTERP like
       binfmt_elf does. Each additional PT_INTERP overwrote the previous
       interpreter, leaking the name allocation and the interpreter file
       reference together with the write denial open_exec() took,
       leaving the file unwritable for as long as the system runs.

 - overlayfs:

     - Compare the full escaped xattr prefix including the trailing dot.
       An xattr like "trusted.overlay.overlayfoo" was misclassified as
       an escaped overlay xattr.

     - Check read access to the copy_file_range() source with the
       source's mounter credentials.

 - super: Thawing a filesystem whose block device was frozen with
   bdev_freeze() deadlocked. Dropping the last block layer freeze
   reference from under s_umount ends up in fs_bdev_thaw() which
   reacquires s_umount on the same task. Pin the superblock with an
   active reference instead and call bdev_thaw() without holding
   s_umount.

 - procfs: Return EACCES instead of success when the ptrace access check
   for namespace links fails.

 - afs: Use afs_dir_get_block() rather than afs_dir_find_block() for
   block 0 in afs_edit_dir_remove(), matching afs_edit_dir_add().

 - Push the memcg gating of ->nr_cached_objects() down into the btrfs
   and shmem callbacks instead of skipping every callback during
   non-root memcg reclaim. The blanket check short-circuited XFS whose
   inode reclaim hook is intentionally driven from per-memcg contexts to
   free memcg-charged slab.

 - eventpoll: Pin files while checking reverse paths.

   Since struct file became SLAB_TYPESAFE_BY_RCU a concurrent close
   could free and recycle the file under the check which then took and
   dropped the f_lock of whatever live file now occupies that slot.

* tag 'vfs-7.2-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits)
  super: fix emergency thaw deadlock on frozen block devices
  pidfs: make pidfs_ino_lock static
  eventpoll: pin files while checking reverse paths
  fs: push nr_cached_objects memcg gating into individual filesystems
  afs: Fix afs_edit_dir_remove() to get, not find, block 0
  iomap: prevent ioend merge when io_private differs
  iomap: add comments for ifs_clear/set_range_dirty()
  iomap: fix out-of-bounds bitmap_set() with zero-length range
  iomap: fix incorrect did_zero setting in iomap_zero_iter()
  iomap: support invalidating partial folios
  iomap: correct the range of a partial dirty clear
  fs/super: fix emergency thaw double-unlock of s_umount
  pidfs: handle FS_IOC32_GETVERSION in compat ioctl
  ovl: check access to copy_file_range source with src mounter creds
  proc: Fix broken error paths for namespace links
  pidfs: add pidfs_dentry_open() helper
  selftests/pidfd: check PIDFD_THREAD survives open_by_handle_at()
  pidfs: preserve thread pidfds reopened by file handle
  ovl: fix trusted xattr escape prefix matching
  selftests/fuse: add ACL_DONT_CACHE regression test
  ...

1 files changed, 21 insertions, 0 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e1f46a0016fc..5407e4200460 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -520,6 +520,22 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
 	return (memcg == root_mem_cgroup);
 }
 
+/**
+ * mem_cgroup_shrink_is_root - is this a global or root-memcg shrink invocation?
+ * @sc: shrink_control describing the current shrinker call
+ *
+ * Returns true when @sc represents a global reclaim shrink (sc->memcg == NULL)
+ * or a root-memcg shrink, i.e. not a per-memcg iteration of
+ * shrink_slab_memcg(). Filesystems whose ->nr_cached_objects()/
+ * ->free_cached_objects() implementations operate on filesystem-global state
+ * and do not honour sc->memcg can use this to early-return 0 in per-memcg
+ * contexts.
+ */
+static inline bool mem_cgroup_shrink_is_root(struct shrink_control *sc)
+{
+	return !sc->memcg || mem_cgroup_is_root(sc->memcg);
+}
+
 static inline bool obj_cgroup_is_root(const struct obj_cgroup *objcg)
 {
 	return objcg->is_root;
@@ -1071,6 +1087,11 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
 	return true;
 }
 
+static inline bool mem_cgroup_shrink_is_root(struct shrink_control *sc)
+{
+	return true;
+}
+
 static inline bool obj_cgroup_is_root(const struct obj_cgroup *objcg)
 {
 	return true;