Re: [Libguestfs] [PATCH nbdkit] New ondemand plugin.

>> +/* Because we rewind the exportsdir handle, we need a lock to protect >> + * list_exports from being called in parallel. >> + */ >> +static pthread_mutex_t exports_lock = PTHREAD_MUTEX_INITIALIZER; > > An alternative is to diropen() each time .list_exports gets called. > Either way should work, though. diropen == opendir?

> I still have some pending patches to improve .list_exports (split > out a .default_export function, add an is_tls parameter), so there > may be some churn in this area (for that matter, I have not yet > pushed my patches for .list_exports in the file plugin, because I > was trying to minimize churn while working on pending patches). > We'll just have to see how it goes; I don't mind rebasing. Right - this is indeed one major reason I sent this for review - it's a new plugin which integrally uses list_exports.

>> +/* Since clients that want multi-conn should all pass the same export >> + * name, this is safe. >> + */ >> +static int >> +ondemand_can_multi_conn (void *handle) >> +{ >> + return 1; >> +} > > Hmm. Are you permitting multiple clients to the same export, or did > you decide that was too likely to cause fs corruption, and locking > out users on the same export? The docs above said otherwise, making > this look wrong. So I think this is wrong because my locking implementation will prevent the (single) client from connecting multiple times. That's a bug: we should allow the same client to connect multiple times, which I believe is safe. However that requires client UUID ...