go-nfs
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willscott
Unnecessary error messages for non-errors
While using go-nfs for github.com/u-root/sidecore, I see messages like this: 2023/12/29 20:47:15 [ERROR] No file for lookup of debconf-communicate 20:47:15 [ERROR] call to 0x102a2b490 failed: No such file or directory: file does not exist
I don't think this should be an error, or, at least, more information would be helpful. I'm still trying to see why this happens. Any ideas?
Thanks.
oh ho, it's supposed to be there but is not. It's almost as though it came back from a readdir but the stat failed?
One thing that would be helpful is some way to enable per-request logging, since it is not always possible to use wireshark (I'm running nfs3 over ssh).
More as I learn it.
ah, ok, it seems to be the kernel trying to do something? maybe set atime? still looking.
OK, the code for lookup I think could be changed. nfs_onlookup should be able to use Lstat, not Readdir, as readdir is a very inefficient way to do a lookup (just image a directory with 10k+ entries and repeated lookups ... this happens. Or 1M. This happens).
I'm surprised that billy has no lookup operation, but I think Lstat would serve. Thoughts?
I was actually thinking the same thing (in practice, directories are not usually large enough to make a difference, but it's a simple optimization to make).
I just discovered LOG_LEVEL, which removes the extra prints. It seems to default to LOG_ERROR? I think it ought to be a higher level. Although, in general, log messages of any kind in a Go package are frowned upon ...
- when using this library in a larger program, you can connect it up to whatever logging system is in use via
SetLoggerhttps://github.com/willscott/go-nfs/blob/master/log.go#L61 - I think you're right that it may be worthwhile to differentiate between recoverable/non-recoverable errors at the library versus at the protocol level.
- The inefficiency in onlookup is a good call. I'll file a separate issue to track that.
https://github.com/willscott/go-nfs/blob/ea1b85ea632bdbe1417274b7f55c93aa30c298f5/conn.go#L130
I'd suggest removing this print. especially for shells, which do a lot of stats for PATH resolution, I am getting a lot of prints.
This is a file system error, and there are always a lot of these, and they are not really NFS-level failures,