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Fri, 5 Jul 2019 15:27:56 +0000 Received: from YTXPR01MB0285.CANPRD01.PROD.OUTLOOK.COM ([fe80::9cc8:c3b7:19c2:7baf]) by YTXPR01MB0285.CANPRD01.PROD.OUTLOOK.COM ([fe80::9cc8:c3b7:19c2:7baf%4]) with mapi id 15.20.2032.022; Fri, 5 Jul 2019 15:27:56 +0000 From: Rick Macklem To: "freebsd-current@FreeBSD.org" CC: Jilles Tjoelker , Alan Somers , "kib@freebsd.org" Subject: Re: [Differential] D20584: add a linux compatible copy_file_range(2) syscall Thread-Topic: [Differential] D20584: add a linux compatible copy_file_range(2) syscall Thread-Index: ZWFiZDk2OGQzOWJhMWJjMTFmOGI0ODBmMTU5IF0fasTlG6fZzw== Date: Fri, 5 Jul 2019 15:27:56 +0000 Message-ID: References: , In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 38031f03-e1ed-4093-daff-08d7015d5ac5 x-microsoft-antispam: BCL:0; PCL:0; RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600148)(711020)(4605104)(1401327)(2017052603328)(7193020); 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spf=pass (mx1.freebsd.org: domain of rmacklem@uoguelph.ca designates 40.107.66.70 as permitted sender) smtp.mailfrom=rmacklem@uoguelph.ca X-Spamd-Result: default: False [-3.94 / 15.00]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; R_SPF_ALLOW(-0.20)[+ip4:40.107.0.0/16]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[uoguelph.ca]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; TO_DN_SOME(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; IP_SCORE(-1.03)[ipnet: 40.64.0.0/10(-2.89), asn: 8075(-2.19), country: US(-0.06)]; MX_GOOD(-0.01)[cached: mx2.hc184-76.ca.iphmx.com]; NEURAL_HAM_SHORT(-0.61)[-0.608,0]; RCVD_IN_DNSWL_NONE(0.00)[70.66.107.40.list.dnswl.org : 127.0.3.0]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:8075, ipnet:40.64.0.0/10, country:US]; RCVD_TLS_LAST(0.00)[] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Jul 2019 15:28:00 -0000 jilles wrote in copy_file_range.2:99 > The Linux man page (from http://man7.org/linux/man->pages/man2/copy_file_= range.2.html ) says that a non-zero flags argument will cause >the call to = return an [EINVAL] error. I think that is better than ignoring the argument= >completely since it allows adding flags more safely (since there will not= be existing >applications that pass in, for example, uninitialized data as= flags). The fun part is that the Linux folks are already discussing adding flags. I don't know if they are already in Linux-next (or whatever they call their= next release), but it sounded like they were headed that way. As such, I thought ignoring "flags" would be easier than returning EINVAL f= or code that works on Linux. However, I can see the counter argument, which is "returning EINVAL will indicate that the Linux flag isn't used on FreeBSD", so that developers wil= l become aware of that. What do others think w.r.t. which is the better approach? rick