Hi Stefan, first off, CouchDB 1.6.1 is no longer supported by this project AND it has a long list of CVEs[1] against it. You REALLY should be operating on a newer version.
Secondly, just to understand your motivation: you think closing and opening the fds after the file:rename/2 call will make things work for your SMB operation? If yes, the only think I could spot that is substantially different, is that the NewFd position is advanced implicitly by the underlying file:pread/3 in [2] and your SwappedFd doesn’t get the same treatment, but I don’t know why that should block the gen server call, as that only does some refcounting updates[3]. While this includes stopping the gen_server[4], I don’t see how the Pid this operates on should be any different under your patch. So: 1. How did you verify that the gen_server:call/3 call never returns? 2. Do you get any pertinent lines (especially crashes) in your couch.log? 3. Can you share your environment where you get to compile 1.6.1 successfully, so we can try and reproduce this? 4. Could it be that your SMB implementation doesn’t allow for opening and closing files in this quick succession (with our without a rename in the mix)? [1]: https://docs.couchdb.org/en/stable/cve/index.html [2]: https://github.com/apache/couchdb/blob/1.6.x/src/couchdb/couch_db_updater.erl#L179 [3]: https://github.com/apache/couchdb/blob/1.6.x/src/couchdb/couch_db.erl#L1122-L1130 [4]: https://github.com/apache/couchdb/blob/1.6.x/src/couchdb/couch_ref_counter.erl#L84 Best Jan — Professional Support for Apache CouchDB: https://neighbourhood.ie/couchdb-support/ 24/7 Observation for your CouchDB Instances: https://opservatory.app > On 28. Feb 2023, at 10:19, Stefan Kral <stefan.k...@emlix.com> wrote: > > Hi, > > I'm experimenting with a CouchDB setup on a SMB mount point. I know this > is not supported, but I ran into a (maybe simple) problem I don't > understand. Maybe someone of you can give a hint easily (that would be > amazing). > > Given the following patch (I need to close/reopen the file descriptors > after renaming) for the function > https://github.com/apache/couchdb/blob/1.6.x/src/couchdb/couch_db_updater.erl#L176 > >> 1 --- a/src/couchdb/couch_db_updater.erl >> 2 +++ b/src/couchdb/couch_db_updater.erl >> 3 @@ -202,8 +202,18 @@ handle_call({compact_done, CompactFilepath}, _From, >> #db{filepath=Path}=Db) -> >> 4 RootDir = couch_config:get("couchdb", "database_dir", "."), >> 5 couch_file:delete(RootDir, Filepath), >> 6 ok = file:rename(CompactFilepath, Filepath), >> 7 + >> 8 + ok = couch_file:close(NewDb#db.updater_fd), >> 9 + ok = couch_file:close(NewDb#db.fd), >> 10 + {ok, SwappedFd} = couch_file:open(Filepath), >> 11 + SwappedReaderFd = open_reader_fd(Filepath, Db#db.options), >> 12 + SwappedDb = NewDb2#db{ >> 13 + fd = SwappedReaderFd, >> 14 + updater_fd = SwappedFd >> 15 + }, >> 16 + unlink(SwappedFd), >> 17 close_db(Db), >> 18 - NewDb3 = refresh_validate_doc_funs(NewDb2), >> 19 + NewDb3 = refresh_validate_doc_funs(SwappedDb), >> 20 ok = gen_server:call(Db#db.main_pid, {db_updated, NewDb3}, >> infinity), >> 21 couch_db_update_notifier:notify({compacted, NewDb3#db.name}), >> 22 ?LOG_INFO("Compaction for db \"~s\" completed.", [Db#db.name]), > > then the gen_server:call() of line 20 never returns. > > Is there a major issue with this approach or just a minor mistake in my > implementation? > > > Thank you for having a look, > Stefan
