fsnotify: Open handle with O_PATH, v2

Otherwise if the mark is set up on link we end
with -ELOOP error trying to open it. Thus, use
O_PATH pointing the kernel that we're not going
to read/write this descriptor.
Repored-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

fsnotify.c

@@ -114,7 +114,7 @@ static int open_handle(unsigned int s_dev, unsigned long i_ino,
 		goto out;
 	}
 
-	fd = sys_open_by_handle_at(mntfd, (void *)&handle, 0);
+	fd = sys_open_by_handle_at(mntfd, (void *)&handle, O_PATH);
 	if (fd < 0) {
 		errno = -fd;
 		pr_perror("Can't open file handle for 0x%08x:0x%016lx",

include/fcntl.h

@@ -29,4 +29,8 @@ struct f_owner_ex {
 # define F_GETPIPE_SZ	(F_LINUX_SPECIFIC_BASE + 8)
 #endif
 
+#ifndef O_PATH
+# define O_PATH		010000000
+#endif
+
 #endif /* __CR_ASM_GENERIC_FCNTL_H__ */