Thread: copy_file_range is now a Linux kernel call
Buildfarm member caiman just came back online after some time AWOL, and it's not happy. The problem evidently is that pg_rewind's copy_file_range function conflicts with a recently added Linux system call: http://man7.org/linux/man-pages/man2/copy_file_range.2.html Looks like we'd better rename our function. Anybody have an idea more creative than "pg_copy_file_range"? (At some point somebody might want to think about fixing this function so it can make use of the kernel call when available. But that's more work than I care to do right now, and certainly more change than I'd want to back-patch.) regards, tom lane
Hi, On 2018-01-02 22:44:04 -0500, Tom Lane wrote: > Buildfarm member caiman just came back online after some time AWOL, and > it's not happy. The problem evidently is that pg_rewind's copy_file_range > function conflicts with a recently added Linux system call: > > http://man7.org/linux/man-pages/man2/copy_file_range.2.html > Heh, just observed the same: http://archives.postgresql.org/message-id/20180103033425.w7jkljth3e26sduc%40alap3.anarazel.de > Looks like we'd better rename our function. Anybody have an idea > more creative than "pg_copy_file_range"? I'd rather name it pg_rewind specific, something like rwnd_copy_file_range or such. It's not a generic range copying facility, given the way it computes source/target file names. > (At some point somebody might want to think about fixing this function > so it can make use of the kernel call when available. But that's more > work than I care to do right now, and certainly more change than I'd want > to back-patch.) If so we'd probably want to do so in a more generic facility than what pg_rewind uses. But for now it indeed seems like a bad idea to do so. Besides the backpatch concern you mention, the functionality is also just present in an unreleased glibc version... Greetings, Andres Freund
Andres Freund <andres@anarazel.de> writes: > On 2018-01-02 22:44:04 -0500, Tom Lane wrote: >> Looks like we'd better rename our function. Anybody have an idea >> more creative than "pg_copy_file_range"? > I'd rather name it pg_rewind specific, OK ... > something like > rwnd_copy_file_range or such. Bleah --- "rwnd" is unpronounceable and not an abbreviation we're currently using anywhere. If we go that way, let's brave carpal tunnel syndrome by calling it "rewind_copy_file_range". But I'm not that happy with any of these. Filipe Rosset pointed out to me off-list that we're not the only ones feeling the pain: https://sourceforge.net/p/e2fsprogs/code/ci/01551bdba16ab16512a01affe02ade32c41ede8a Maybe go with copy_file_chunk like e2fsprogs did? regards, tom lane
Hi, On 2018-01-02 23:08:05 -0500, Tom Lane wrote: > Andres Freund <andres@anarazel.de> writes: > > On 2018-01-02 22:44:04 -0500, Tom Lane wrote: > > something like rwnd_copy_file_range or such. > Bleah --- "rwnd" is unpronounceable and not an abbreviation we're > currently using anywhere. If we go that way, let's brave carpal tunnel > syndrome by calling it "rewind_copy_file_range". But I'm not that > happy with any of these. rewind_copy_file_range works for me. > Filipe Rosset pointed out to me off-list that we're not the only > ones feeling the pain: > > https://sourceforge.net/p/e2fsprogs/code/ci/01551bdba16ab16512a01affe02ade32c41ede8a > > Maybe go with copy_file_chunk like e2fsprogs did? -0.2 - don't think it hurts to signal this isn't a general function. Greetings, Andres Freund
Andres Freund <andres@anarazel.de> writes:
> On 2018-01-02 23:08:05 -0500, Tom Lane wrote:
>> Bleah --- "rwnd" is unpronounceable and not an abbreviation we're
>> currently using anywhere. If we go that way, let's brave carpal tunnel
>> syndrome by calling it "rewind_copy_file_range". But I'm not that
>> happy with any of these.
> rewind_copy_file_range works for me.
>> Maybe go with copy_file_chunk like e2fsprogs did?
> -0.2 - don't think it hurts to signal this isn't a general function.
Fair enough. You want to do the honors, or shall I?
regards, tom lane
On 2018-01-02 23:34:47 -0500, Tom Lane wrote: > Andres Freund <andres@anarazel.de> writes: > > On 2018-01-02 23:08:05 -0500, Tom Lane wrote: > >> Bleah --- "rwnd" is unpronounceable and not an abbreviation we're > >> currently using anywhere. If we go that way, let's brave carpal tunnel > >> syndrome by calling it "rewind_copy_file_range". But I'm not that > >> happy with any of these. > > > rewind_copy_file_range works for me. > > >> Maybe go with copy_file_chunk like e2fsprogs did? > > > -0.2 - don't think it hurts to signal this isn't a general function. > > Fair enough. You want to do the honors, or shall I? Will do tomorrow morning, unless you beat me to it over there on the cold coast. Greetings, Andres Freund