How useful should copy_file_range() be?

Posted Feb 18, 2021 19:21 UTC (Thu) by JoeBuck (subscriber, #2330)
In reply to: How useful should copy_file_range() be? by Deewiant
Parent article: How useful should copy_file_range() be?

Looks like others can just port the Rust fix.

How useful should copy_file_range() be?

Posted Feb 18, 2021 22:37 UTC (Thu) by drinkcat (subscriber, #106553) [Link] (2 responses)

That workaround should work in most cases. But another tricky thing with copy_file_range is that in case of partial writes, it's supposed to be able to seek in the input file (which is not usually possible on generated files).

How useful should copy_file_range() be?

Posted Feb 18, 2021 23:49 UTC (Thu) by JoeBuck (subscriber, #2330) [Link] (1 responses)

Perhaps I'm missing something, but I thought that for the generated files, the call always transfers 0 bytes, and the Rust patch immediately falls back when it sees this. So how is seeking an issue?

How useful should copy_file_range() be?

Posted Feb 19, 2021 0:17 UTC (Fri) by drinkcat (subscriber, #106553) [Link]

Yeah... except for sysfs files that report a size of 4096 bytes, copy_file_range would appear to work on these.