fuse: respect FOPEN_KEEP_CACHE on opendir

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

Fixes: 7de64d5 ("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>

Author: amir73il

fs/fuse/dir.c

@@ -1681,6 +1681,8 @@ static int fuse_dir_open(struct inode *inode, struct file *file)
 		 */
 		if (ff->open_flags & (FOPEN_STREAM | FOPEN_NONSEEKABLE))
 			nonseekable_open(inode, file);
+		if (!(ff->open_flags & FOPEN_KEEP_CACHE))
+			invalidate_inode_pages2(inode->i_mapping);
 	}
 
 	return err;