Date: Fri, 5 Jul 2019 08:26:22 -0600 From: Alan Somers <asomers@freebsd.org> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: "freebsd-current@FreeBSD.org" <freebsd-current@freebsd.org>, "kib@freebsd.org" <kib@freebsd.org> Subject: Re: should a copy_file_range(2) syscall be interrupted via a signal Message-ID: <CAOtMX2jfkcN3tM8oCEtogfeQrnX7_D-xFgAjGbROkrENsFVcQg@mail.gmail.com> In-Reply-To: <YTXPR01MB0285E79DFAAE250FD7A7A181DDF50@YTXPR01MB0285.CANPRD01.PROD.OUTLOOK.COM> References: <YTXPR01MB0285E79DFAAE250FD7A7A181DDF50@YTXPR01MB0285.CANPRD01.PROD.OUTLOOK.COM>
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On Thu, Jul 4, 2019 at 6:29 PM Rick Macklem <rmacklem@uoguelph.ca> wrote: > > Hi, > > I have been working on a Linux compatible copy_file_range(2) syscall > (the current code can be found at https://reviews.freebsd.org/D20584). > > One outstanding issue is how it should deal with signals. > Right now, I have vn_start_write() without PCATCH, so that it won't be > interrupted by a signal, but I notice that vn_write() {ie. write syscall } does > have PCATCH on vn_start_write() and so does vn_rdwr() when it is called > without IO_NODELOCKED. > > I am thinking that copy_file_range(2) should do this also. > However, if it returns an error, it is impossible for the caller to know how much > of the data range got copied. > > What do you think the copy_file_range(2) code should do? > > Thanks, rick > ps: I've used FreeBSD-current@ this time, to see if I get more replies than I > did using FreeBSD-fs@. I though copy_file_range(2) is allowed to return short. Why can't it do that if it gets interrupted?
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