From patchwork Fri May 17 18:36:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Harkes X-Patchwork-Id: 10948355 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8F6C06C5 for ; Fri, 17 May 2019 18:37:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8113D28173 for ; Fri, 17 May 2019 18:37:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 75895283C9; Fri, 17 May 2019 18:37:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D001828421 for ; Fri, 17 May 2019 18:37:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728865AbfEQShQ (ORCPT ); Fri, 17 May 2019 14:37:16 -0400 Received: from hurricane.elijah.cs.cmu.edu ([128.2.209.191]:57606 "EHLO hurricane.elijah.cs.cmu.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729367AbfEQShC (ORCPT ); Fri, 17 May 2019 14:37:02 -0400 Received: from jaharkes by hurricane.elijah.cs.cmu.edu with local (Exim 4.92) (envelope-from ) id 1hRhj2-0000oU-Tg; Fri, 17 May 2019 14:37:00 -0400 From: Jan Harkes To: Andrew Morton Cc: Jan Harkes , linux-fsdevel@vger.kernel.org, Arnd Bergmann Subject: [PATCH 10/22] coda: stop using 'struct timespec' in user API Date: Fri, 17 May 2019 14:36:48 -0400 Message-Id: <562b7324149461743e4fbe2fedbf7c242f7e274a.1558117389.git.jaharkes@cs.cmu.edu> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Arnd Bergmann We exchange file timestamps with user space using psdev device read/write operations with a fixed but architecture specific binary layout. On 32-bit systems, this uses a 'timespec' structure that is defined by the C library to contain two 32-bit values for seconds and nanoseconds. As we get ready for the year 2038 overflow of the 32-bit signed seconds, the kernel now uses 64-bit timestamps internally, and user space will do the same change by changing the 'timespec' definition in the future. Unfortunately, this breaks the layout of the coda_vattr structure, so we need to redefine that in terms of something that does not change. I'm introducing a new 'struct vtimespec' structure here that keeps the existing layout, and the same change has to be done in the coda user space copy of linux/coda.h before anyone can use that on a 32-bit architecture with 64-bit time_t. An open question is what should happen to actual times past y2038, as they are now truncated to the last valid date when sent to user space, and interpreted as pre-1970 times when a timestamp with the MSB set is read back into the kernel. Alternatively, we could change the new timespec64_to_coda()/coda_to_timespec64() functions to use a different interpretation and extend the available range further to the future by disallowing past timestamps. This would require more changes in the user space side though. Acked-by: Jan Harkes Link: https://patchwork.kernel.org/patch/10474735/ Signed-off-by: Arnd Bergmann Signed-off-by: Jan Harkes --- Documentation/filesystems/coda.txt | 11 ++++--- fs/coda/coda_linux.c | 50 +++++++++++++++++++++++------- include/uapi/linux/coda.h | 20 ++++++++++-- 3 files changed, 62 insertions(+), 19 deletions(-) diff --git a/Documentation/filesystems/coda.txt b/Documentation/filesystems/coda.txt index 61311356025d..ea5969068895 100644 --- a/Documentation/filesystems/coda.txt +++ b/Documentation/filesystems/coda.txt @@ -481,7 +481,10 @@ kernel support. - + struct vtimespec { + long tv_sec; /* seconds */ + long tv_nsec; /* nanoseconds */ + }; struct coda_vattr { enum coda_vtype va_type; /* vnode type (for create) */ @@ -493,9 +496,9 @@ kernel support. long va_fileid; /* file id */ u_quad_t va_size; /* file size in bytes */ long va_blocksize; /* blocksize preferred for i/o */ - struct timespec va_atime; /* time of last access */ - struct timespec va_mtime; /* time of last modification */ - struct timespec va_ctime; /* time file changed */ + struct vtimespec va_atime; /* time of last access */ + struct vtimespec va_mtime; /* time of last modification */ + struct vtimespec va_ctime; /* time file changed */ u_long va_gen; /* generation number of file */ u_long va_flags; /* flags defined for file */ dev_t va_rdev; /* device special file represents */ diff --git a/fs/coda/coda_linux.c b/fs/coda/coda_linux.c index f3d543dd9a98..8addcd166908 100644 --- a/fs/coda/coda_linux.c +++ b/fs/coda/coda_linux.c @@ -66,6 +66,32 @@ unsigned short coda_flags_to_cflags(unsigned short flags) return coda_flags; } +static struct timespec64 coda_to_timespec64(struct vtimespec ts) +{ + /* + * We interpret incoming timestamps as 'signed' to match traditional + * usage and support pre-1970 timestamps, but this breaks in y2038 + * on 32-bit machines. + */ + struct timespec64 ts64 = { + .tv_sec = ts.tv_sec, + .tv_nsec = ts.tv_nsec, + }; + + return ts64; +} + +static struct vtimespec timespec64_to_coda(struct timespec64 ts64) +{ + /* clamp the timestamps to the maximum range rather than wrapping */ + struct vtimespec ts = { + .tv_sec = lower_32_bits(clamp_t(time64_t, ts64.tv_sec, + LONG_MIN, LONG_MAX)), + .tv_nsec = ts64.tv_nsec, + }; + + return ts; +} /* utility functions below */ void coda_vattr_to_iattr(struct inode *inode, struct coda_vattr *attr) @@ -105,11 +131,11 @@ void coda_vattr_to_iattr(struct inode *inode, struct coda_vattr *attr) if (attr->va_size != -1) inode->i_blocks = (attr->va_size + 511) >> 9; if (attr->va_atime.tv_sec != -1) - inode->i_atime = timespec_to_timespec64(attr->va_atime); + inode->i_atime = coda_to_timespec64(attr->va_atime); if (attr->va_mtime.tv_sec != -1) - inode->i_mtime = timespec_to_timespec64(attr->va_mtime); + inode->i_mtime = coda_to_timespec64(attr->va_mtime); if (attr->va_ctime.tv_sec != -1) - inode->i_ctime = timespec_to_timespec64(attr->va_ctime); + inode->i_ctime = coda_to_timespec64(attr->va_ctime); } @@ -130,12 +156,12 @@ void coda_iattr_to_vattr(struct iattr *iattr, struct coda_vattr *vattr) vattr->va_uid = (vuid_t) -1; vattr->va_gid = (vgid_t) -1; vattr->va_size = (off_t) -1; - vattr->va_atime.tv_sec = (time_t) -1; - vattr->va_atime.tv_nsec = (time_t) -1; - vattr->va_mtime.tv_sec = (time_t) -1; - vattr->va_mtime.tv_nsec = (time_t) -1; - vattr->va_ctime.tv_sec = (time_t) -1; - vattr->va_ctime.tv_nsec = (time_t) -1; + vattr->va_atime.tv_sec = (long) -1; + vattr->va_atime.tv_nsec = (long) -1; + vattr->va_mtime.tv_sec = (long) -1; + vattr->va_mtime.tv_nsec = (long) -1; + vattr->va_ctime.tv_sec = (long) -1; + vattr->va_ctime.tv_nsec = (long) -1; vattr->va_type = C_VNON; vattr->va_fileid = -1; vattr->va_gen = -1; @@ -175,13 +201,13 @@ void coda_iattr_to_vattr(struct iattr *iattr, struct coda_vattr *vattr) vattr->va_size = iattr->ia_size; } if ( valid & ATTR_ATIME ) { - vattr->va_atime = timespec64_to_timespec(iattr->ia_atime); + vattr->va_atime = timespec64_to_coda(iattr->ia_atime); } if ( valid & ATTR_MTIME ) { - vattr->va_mtime = timespec64_to_timespec(iattr->ia_mtime); + vattr->va_mtime = timespec64_to_coda(iattr->ia_mtime); } if ( valid & ATTR_CTIME ) { - vattr->va_ctime = timespec64_to_timespec(iattr->ia_ctime); + vattr->va_ctime = timespec64_to_coda(iattr->ia_ctime); } } diff --git a/include/uapi/linux/coda.h b/include/uapi/linux/coda.h index ed8cb263e482..fc5f7874208a 100644 --- a/include/uapi/linux/coda.h +++ b/include/uapi/linux/coda.h @@ -211,6 +211,20 @@ struct CodaFid { */ enum coda_vtype { C_VNON, C_VREG, C_VDIR, C_VBLK, C_VCHR, C_VLNK, C_VSOCK, C_VFIFO, C_VBAD }; +#ifdef __linux__ +/* + * This matches the traditional Linux 'timespec' structure binary layout, + * before using 64-bit time_t everywhere. Overflows in y2038 on 32-bit + * architectures. + */ +struct vtimespec { + long tv_sec; /* seconds */ + long tv_nsec; /* nanoseconds */ +}; +#else +#define vtimespec timespec +#endif + struct coda_vattr { long va_type; /* vnode type (for create) */ u_short va_mode; /* files access mode and type */ @@ -220,9 +234,9 @@ struct coda_vattr { long va_fileid; /* file id */ u_quad_t va_size; /* file size in bytes */ long va_blocksize; /* blocksize preferred for i/o */ - struct timespec va_atime; /* time of last access */ - struct timespec va_mtime; /* time of last modification */ - struct timespec va_ctime; /* time file changed */ + struct vtimespec va_atime; /* time of last access */ + struct vtimespec va_mtime; /* time of last modification */ + struct vtimespec va_ctime; /* time file changed */ u_long va_gen; /* generation number of file */ u_long va_flags; /* flags defined for file */ cdev_t va_rdev; /* device special file represents */