splice: report related fsnotify events

The fsnotify ACCESS and MODIFY event are missing when manipulating a file
with splice(2).
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Jan Kara <jack@suse.cz>
Message-Id: <20230322062519.409752-1-cccheng@synology.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/splice.c

@@ -30,6 +30,7 @@
 #include <linux/export.h>
 #include <linux/syscalls.h>
 #include <linux/uio.h>
+#include <linux/fsnotify.h>
 #include <linux/security.h>
 #include <linux/gfp.h>
 #include <linux/socket.h>
@@ -1165,6 +1166,9 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out,
 		ret = do_splice_from(ipipe, out, &offset, len, flags);
 		file_end_write(out);
 
+		if (ret > 0)
+			fsnotify_modify(out);
+
 		if (!off_out)
 			out->f_pos = offset;
 		else
@@ -1188,6 +1192,10 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out,
 			flags |= SPLICE_F_NONBLOCK;
 
 		ret = splice_file_to_pipe(in, opipe, &offset, len, flags);
+
+		if (ret > 0)
+			fsnotify_access(in);
+
 		if (!off_in)
 			in->f_pos = offset;
 		else