On Sat, 29 Mar 2008 16:05:49 -0400 Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > > On Sat, 2008-03-29 at 15:24 -0400, Jeff Layton wrote: > > On Sat, 29 Mar 2008 12:44:11 -0400 > > Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > > > Userland has the clnt_geterr() function that returns more detailed 'RPC > > > level' errors. While that 'error function call' approach doesn't work in > > > a multi-threaded environment, we might still be able to add the > > > equivalent of a pointer to an 'rpc_err' structure to the rpc_task, and > > > then have functions like call_timeout() (and especially call_verify()!) > > > fill in more detailed error info if that pointer is non-zero? > > > > > > > I'm not sure we really need this, do we? > > > > Should it really be the business of the RPC layer to sanitize the > > tk_status like this? It seems like the NFS layer ought to be > > translating "illegal" errors from the RPC layer into more generic ones > > where needed rather than relying on the RPC layer to do it, though > > maybe I'm not thinking about the RPC layer in the right way here... > > Yes and no. The RPC error reports are sometimes more complex than what > we can fit into a single 32-bit error code. I'm thinking in particular > of the RPC_AUTH_* errors (EACCESS just doesn't do them justice), and > RPC_PROG_MISMATCH error. > > In the case of RPC_PROG_MISMATCH, it would, for instance, be really > useful for the in-kernel mount code to be able to also retrieve the > 'mismatch_info' structure (see RFC1831), which tells you exactly which > program versions are actually supported on that port. > > An extra optional pointer to a structure in the rpc_task won't cost us > much, but could possibly provide a lot of interesting information that > we are currently ignoring. > Ok, that makes sense. Yes, adding a new pointer to the rpc_task doesn't sound too costly. The hard part is getting this pointer from the higher layers that would interpret this info to the correct RPC functions that could populate it. I don't really have a good feel for how we'd populate this new pointer as well. For instance, you'd want to hang a mismatch_info struct on it for the case of RPC_PROG_MISMATCH, but in the case I was trying to fix above, we'd just want a simple 32-bit error code. How will the RPC engine know what this pointer points to? Or should we just make it a new struct that has fields for each possibility? -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
