Fixing the unfixable autofs ABI
Posted Apr 30, 2012 21:09 UTC (Mon) by quotemstr
Parent article: Fixing the unfixable autofs ABI
Packetized pipes seem like a bad idea.
1) O_DIRECT doesn't what this patch says it should mean. O_DIRECT means "no buffering", not "weird read(2) games". O_DIRECT on a pipe ought to mean something like "block write(2) until someone blocks in read(2), then memcpy directly to the reader's buffer", and with this patch, O_DIRECT can never mean that for pipes.
2) This "packetized pipe" system looks like an invitation for data loss. It's one thing to create a pipe mode that preserves message boundaries (like NT's PIPE_TYPE_MESSAGE named pipes), but the right behavior should be to cause read(2) to fail unless the reader gets the whole packet. (That's how NT message pipes work.) Because of the silent data loss issue, these packetized pipes aren't truly general-purpose.
In general, this approach seems like an overly general solution to a very particular problem.
to post comments)