On Fri, 2020-06-05 at 17:27 -0500, Benjamin Marzinski wrote: > On Fri, Jun 05, 2020 at 07:20:26PM +0000, Martin Wilck wrote: > > Hi Ben, > > > > On Thu, 2020-06-04 at 19:30 -0500, Benjamin Marzinski wrote: > > > I recently got a request to add the Oracle ASM filer driver > > > devices > > > to > > > multipath's builtin devnode blacklist. However, instead of > > > having to > > > do > > > always this for each device type individually, I decided to make > > > multipath blacklist all non scsi, nvme, and dasd devnodes by > > > default. > > > This is what the multipath udev rules already do. If people don't > > > like > > > this solution, the alternative is to add another line to the > > > default > > > devnode blacklist like "^(asm/|oracleafd/|ofsctl)". > > > > Thanks, this looks ok. But I'd like to propose an alternative idea: > > Extend the RE syntax in our config file to allow negated regular > > expressions. Like this: > > > > blacklist { > > devnode "!(^(sd[a-z]|dasd[a-z]|nvme[0-9]))" > > } > > > > The "!(${RE})" construct would mean "everything that does not match > > ${RE}". > > This logic would only be applied to an entire regex. > > If a user needs a RE matching with "!(" and ending with ")", she > > can escape > > the exclamation mark "\!(like this)". > > > > AFAICS this could be implemented quite easily (by adding a "bool > > negate" field > > in struct blentry and some simple parser logic), and could be > > applied to other > > REs in the config file as well. We could print this with "multipath > > -t", and > > we wouldn't need to document an exception. > > > > It's also pretty much backwards-compatible, I don't think many > > people use > > regexes starting with "!(" for multipath these days. > > Sure, but since we can only really support negating the whole regular > expression, and c regular expressions don't treat '!' as a special > character, why do we need the prentheses around the regular > expression? > It seems like we can just treat regular expressions starting with '!' > as > negated, and ones starting with "\!" as starting with a literal '!'. > > Do you think that there is much chance that users have blacklist > strings > that start with '!'? There are no devnodes, udev properties, or > protocols that start with that. I don't know of a UUID format that > has > an exclamation point, and while it's possible that a product string > starts with one, it seems really unlikely. >
Sure, just using "!" would be fine, too, and simpler. Does this mean you agree with my proposal in general? Martin -- Dr. Martin Wilck <mwi...@suse.com>, Tel. +49 (0)911 74053 2107 SUSE Software Solutions Germany GmbH HRB 36809, AG Nürnberg GF: Felix Imendörffer -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel