Re: [PATCH 05/32] timerfd/timens: Take into account ns clock offsets

On Wed, Feb 06, 2019 at 11:52:03AM +0300, Cyrill Gorcunov wrote:

On Wed, Feb 06, 2019 at 12:10:39AM +0000, Dmitry Safonov wrote:

quoted

From: Andrei Vagin <redacted>

Make timerfd respect timens offsets.
Provide two helpers timens_clock_to_host() timens_clock_from_host() that
are useful to wire up timens to different kernel subsystems.
Following patches will use timens_clock_from_host(), added here for
completeness.

Signed-off-by: Andrei Vagin <redacted>
Co-developed-by: Dmitry Safonov <redacted>
Signed-off-by: Dmitry Safonov <redacted>
---
 fs/timerfd.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 803ca070d42e..c7ae1e371912 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c

@@ -26,6 +26,7 @@
 #include <linux/syscalls.h>
 #include <linux/compat.h>
 #include <linux/rcupdate.h>
+#include <linux/time_namespace.h>
 
 struct timerfd_ctx {
 	union {

@@ -433,22 +434,27 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 }
 
 static int do_timerfd_settime(int ufd, int flags, 
-		const struct itimerspec64 *new,
+		struct itimerspec64 *new,
 		struct itimerspec64 *old)
 {
 	struct fd f;
 	struct timerfd_ctx *ctx;
 	int ret;
 
-	if ((flags & ~TFD_SETTIME_FLAGS) ||
-		 !itimerspec64_valid(new))
-		return -EINVAL;

Please don't defer this early test of a @flags value. Otherwise
if @flags is invalid you continue fget/put/clock-to-host even
if result will be dropped out then.

Cyrill, you are right. I moved this check together with
itimerspec64_valid(). The idea was to call itimerspec64_valid() after
applying clock offsets but for that, we need to know clockid.

Let's wait a bit for other comments to this patch set and then we will
fix all things what will be found.

Thanks,
Andrei