Merge tag 'vfs-6.19-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "Features:

   - Cheaper MAY_EXEC handling for path lookup. This elides MAY_WRITE
     permission checks during path lookup and adds the
     IOP_FASTPERM_MAY_EXEC flag so filesystems like btrfs can avoid
     expensive permission work.

   - Hide dentry_cache behind runtime const machinery.

   - Add German Maglione as virtiofs co-maintainer.

  Cleanups:

   - Tidy up and inline step_into() and walk_component() for improved
     code generation.

   - Re-enable IOCB_NOWAIT writes to files. This refactors file
     timestamp update logic, fixing a layering bypass in btrfs when
     updating timestamps on device files and improving FMODE_NOCMTIME
     handling in VFS now that nfsd started using it.

   - Path lookup optimizations extracting slowpaths into dedicated
     routines and adding branch prediction hints for mntput_no_expire(),
     fd_install(), lookup_slow(), and various other hot paths.

   - Enable clang's -fms-extensions flag, requiring a JFS rename to
     avoid conflicts.

   - Remove spurious exports in fs/file_attr.c.

   - Stop duplicating union pipe_index declaration. This depends on the
     shared kbuild branch that brings in -fms-extensions support which
     is merged into this branch.

   - Use MD5 library instead of crypto_shash in ecryptfs.

   - Use largest_zero_folio() in iomap_dio_zero().

   - Replace simple_strtol/strtoul with kstrtoint/kstrtouint in init and
     initrd code.

   - Various typo fixes.

  Fixes:

   - Fix emergency sync for btrfs. Btrfs requires an explicit sync_fs()
     call with wait == 1 to commit super blocks. The emergency sync path
     never passed this, leaving btrfs data uncommitted during emergency
     sync.

   - Use local kmap in watch_queue's post_one_notification().

   - Add hint prints in sb_set_blocksize() for LBS dependency on THP"

* tag 'vfs-6.19-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits)
  MAINTAINERS: add German Maglione as virtiofs co-maintainer
  fs: inline step_into() and walk_component()
  fs: tidy up step_into() & friends before inlining
  orangefs: use inode_update_timestamps directly
  btrfs: fix the comment on btrfs_update_time
  btrfs: use vfs_utimes to update file timestamps
  fs: export vfs_utimes
  fs: lift the FMODE_NOCMTIME check into file_update_time_flags
  fs: refactor file timestamp update logic
  include/linux/fs.h: trivial fix: regualr -> regular
  fs/splice.c: trivial fix: pipes -> pipe's
  fs: mark lookup_slow() as noinline
  fs: add predicts based on nd->depth
  fs: move mntput_no_expire() slowpath into a dedicated routine
  fs: remove spurious exports in fs/file_attr.c
  watch_queue: Use local kmap in post_one_notification()
  fs: touch up predicts in path lookup
  fs: move fd_install() slowpath into a dedicated routine and provide commentary
  fs: hide dentry_cache behind runtime const machinery
  fs: touch predicts in do_dentry_open()
  ...

fs/inode.c

@@ -2322,42 +2322,40 @@ out:
 }
 EXPORT_SYMBOL(current_time);
 
-static int inode_needs_update_time(struct inode *inode)
+static int file_update_time_flags(struct file *file, unsigned int flags)
 {
+	struct inode *inode = file_inode(file);
 	struct timespec64 now, ts;
-	int sync_it = 0;
+	int sync_mode = 0;
+	int ret = 0;
 
 	/* First try to exhaust all avenues to not sync */
 	if (IS_NOCMTIME(inode))
 		return 0;
+	if (unlikely(file->f_mode & FMODE_NOCMTIME))
+		return 0;
 
 	now = current_time(inode);
 
 	ts = inode_get_mtime(inode);
 	if (!timespec64_equal(&ts, &now))
-		sync_it |= S_MTIME;
-
+		sync_mode |= S_MTIME;
 	ts = inode_get_ctime(inode);
 	if (!timespec64_equal(&ts, &now))
-		sync_it |= S_CTIME;
-
+		sync_mode |= S_CTIME;
 	if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
-		sync_it |= S_VERSION;
+		sync_mode |= S_VERSION;
 
-	return sync_it;
-}
+	if (!sync_mode)
+		return 0;
 
-static int __file_update_time(struct file *file, int sync_mode)
-{
-	int ret = 0;
-	struct inode *inode = file_inode(file);
-
-	/* try to update time settings */
-	if (!mnt_get_write_access_file(file)) {
-		ret = inode_update_time(inode, sync_mode);
-		mnt_put_write_access_file(file);
-	}
+	if (flags & IOCB_NOWAIT)
+		return -EAGAIN;
 
+	if (mnt_get_write_access_file(file))
+		return 0;
+	ret = inode_update_time(inode, sync_mode);
+	mnt_put_write_access_file(file);
 	return ret;
 }
 
@@ -2377,14 +2375,7 @@ static int __file_update_time(struct file *file, int sync_mode)
  */
 int file_update_time(struct file *file)
 {
-	int ret;
-	struct inode *inode = file_inode(file);
-
-	ret = inode_needs_update_time(inode);
-	if (ret <= 0)
-		return ret;
-
-	return __file_update_time(file, ret);
+	return file_update_time_flags(file, 0);
 }
 EXPORT_SYMBOL(file_update_time);
 
@@ -2406,7 +2397,6 @@ EXPORT_SYMBOL(file_update_time);
 static int file_modified_flags(struct file *file, int flags)
 {
 	int ret;
-	struct inode *inode = file_inode(file);
 
 	/*
 	 * Clear the security bits if the process is not being run by root.
@@ -2415,17 +2405,7 @@ static int file_modified_flags(struct file *file, int flags)
 	ret = file_remove_privs_flags(file, flags);
 	if (ret)
 		return ret;
-
-	if (unlikely(file->f_mode & FMODE_NOCMTIME))
-		return 0;
-
-	ret = inode_needs_update_time(inode);
-	if (ret <= 0)
-		return ret;
-	if (flags & IOCB_NOWAIT)
-		return -EAGAIN;
-
-	return __file_update_time(file, ret);
+	return file_update_time_flags(file, flags);
 }
 
 /**