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From: Deepa Dinamani <deepa.kernel@gmail.com>
To: Trond Myklebust <trondmy@primarydata.com>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"y2038@lists.linaro.org" <y2038@lists.linaro.org>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 18/21] fs: nfs: Make nfs boot time y2038 safe
Date: Thu, 9 Jun 2016 14:10:35 -0700
Message-ID: <CABeXuvoLr7amTYBs5AbMv15Vqx2CQib9F8Qr4GzX9RoZZ9ZnpQ@mail.gmail.com> (raw)
In-Reply-To: <89EF59F9-52D2-4F37-A7A8-52BD0FF7E98E@primarydata.com>

>>boot_time is represented as a struct timespec.
>>struct timespec and CURRENT_TIME are not y2038 safe.
>>Overall, the plan is to use timespec64 for all internal
>>kernel representation of timestamps.
>>CURRENT_TIME will also be removed.
>>Use struct timespec64 to represent boot_time.
>>And, ktime_get_real_ts64() for the boot_time value.
>>
>>boot_time is used to construct the nfs client boot verifier.
>>This will now wrap in 2106 instead of 2038 on 32-bit systems.
>>The server only relies on the value being persistent until
>>reboot so the wrapping should be fine.
>
> We really do not give a damn about wraparound here, since the boot time is
> only ever compared for an exact match, and the odds of two reboots occurring
> exactly 2^32 * 10^9 nanoseconds apart are cosmically small...
> If struct timespec is going away, can we just convert this into a ktime_t?

timespec64 is the same as timespec already on 64 bit machines.
But, yes, we can use ktime_t here.

Did you mean the internal storage value or the wire boo_time used for verifier?
In case you don't want to change the wire value, then we will have a division
operation, every time the verifier needs to be sent.

-Deepa

-Deepa

  reply index

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-09  5:04 [PATCH 00/21] Delete CURRENT_TIME and CURRENT_TIME_SEC macros Deepa Dinamani
2016-06-09  5:04 ` [PATCH 01/21] fs: Replace CURRENT_TIME_SEC with current_fs_time() Deepa Dinamani
2016-06-09  7:35   ` Jan Kara
2016-06-09 19:15     ` Linus Torvalds
2016-06-09 20:41       ` Deepa Dinamani
2016-06-09 12:31   ` Bob Copeland
2016-06-10 22:21   ` Arnd Bergmann
2016-06-11  5:03     ` Deepa Dinamani
2016-06-11 20:55       ` Arnd Bergmann
2016-06-09  5:04 ` [PATCH 02/21] fs: ext4: Use current_fs_time() for inode timestamps Deepa Dinamani
2016-06-09 18:45   ` Linus Torvalds
2016-06-09 18:55     ` Linus Torvalds
2016-06-10 22:19     ` [Y2038] " Arnd Bergmann
2016-06-14 17:55       ` Deepa Dinamani
2016-06-14 20:59         ` Arnd Bergmann
2016-06-09  5:04 ` [PATCH 03/21] fs: ubifs: " Deepa Dinamani
2016-06-09  5:04 ` [PATCH 05/21] fs: jfs: Replace CURRENT_TIME_SEC by current_fs_time() Deepa Dinamani
2016-06-09  5:04 ` [PATCH 06/21] fs: udf: Replace CURRENT_TIME with current_fs_time() Deepa Dinamani
2016-06-09  7:41   ` Jan Kara
2016-06-10  0:53     ` Deepa Dinamani
2016-06-09  5:04 ` [PATCH 07/21] fs: cifs: Replace CURRENT_TIME by current_fs_time() Deepa Dinamani
2016-06-09  5:04 ` [PATCH 08/21] fs: cifs: Replace CURRENT_TIME with ktime_get_real_ts() Deepa Dinamani
2016-06-09  5:04 ` [PATCH 09/21] fs: cifs: Replace CURRENT_TIME by get_seconds Deepa Dinamani
2016-06-09  5:04 ` [PATCH 10/21] fs: f2fs: Use ktime_get_real_seconds for sit_info times Deepa Dinamani
2016-06-09  5:04 ` [PATCH 11/21] drivers: staging: lustre: Replace CURRENT_TIME with current_fs_time() Deepa Dinamani
2016-06-11  0:36   ` [lustre-devel] " James Simmons
2016-06-11  1:53     ` Andreas Dilger
2016-06-09  5:04 ` [PATCH 12/21] block: rbd: Replace non inode " Deepa Dinamani
2016-06-09  5:04 ` [PATCH 13/21] fs: ocfs2: Use time64_t to represent orphan scan times Deepa Dinamani
2016-06-09  5:04 ` [PATCH 14/21] fs: ocfs2: Replace CURRENT_TIME with ktime_get_real_seconds() Deepa Dinamani
2016-06-09  5:04 ` [PATCH 15/21] time: Add time64_to_tm() Deepa Dinamani
2016-06-14 21:18   ` John Stultz
2016-06-15 17:44     ` Deepa Dinamani
2016-06-17 20:52       ` John Stultz
2016-06-17 20:59         ` Deepa Dinamani
2016-06-17 21:06           ` Arnd Bergmann
2016-06-09  5:05 ` [PATCH 16/21] fnic: Use time64_t to represent trace timestamps Deepa Dinamani
2016-06-09  5:05 ` [PATCH 17/21] audit: Use timespec64 to represent audit timestamps Deepa Dinamani
2016-06-09 14:31   ` Steve Grubb
2016-06-09 23:59     ` Richard Guy Briggs
2016-06-10  0:19       ` Steve Grubb
2016-06-10  1:44         ` Richard Guy Briggs
2016-06-15 21:23       ` Paul Moore
2016-06-10  0:45     ` Deepa Dinamani
2016-06-09  5:05 ` [PATCH 18/21] fs: nfs: Make nfs boot time y2038 safe Deepa Dinamani
2016-06-09 19:23   ` Trond Myklebust
2016-06-09 21:10     ` Deepa Dinamani [this message]
2016-06-10 13:12       ` Anna Schumaker
2016-06-10 14:02         ` Trond Myklebust
2016-06-09  5:05 ` [PATCH 19/21] libceph: Remove CURRENT_TIME references Deepa Dinamani
2016-06-09  5:05 ` [PATCH 20/21] libceph: Replace CURRENT_TIME with ktime_get_real_ts Deepa Dinamani
2016-06-09  5:05 ` [PATCH 21/21] time: Delete CURRENT_TIME_SEC and CURRENT_TIME macro Deepa Dinamani
2016-06-14 21:20   ` John Stultz
2016-06-09  7:51 ` [PATCH 00/21] Delete CURRENT_TIME and CURRENT_TIME_SEC macros Felipe Balbi

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