Re: CVS commit: src/external/cddl/osnet/dist/uts/common/fs/zfs

[Taylor R Campbell <campbell+netbsd-source-changes-d%mumble.net@localhost>]

> Module Name:    src
> Committed By:   hannken
> Date:           Thu May  7 09:12:03 UTC 2020
> 
> Modified Files:
>         src/external/cddl/osnet/dist/uts/common/fs/zfs: zfs_vnops.c
> 
> Log Message:
> Revert Rev. 1.63 and add a comment why we have to zil_commit() here:
> 
> Operation zfs_znode.c::zfs_zget_cleaner() depends on this
> zil_commit() as a barrier to guarantee the znode cannot
> get freed before its log entries are resolved.

We must be doing something wrong.

The only times we should ever call zil_commit are when someone called
fsync or the file system is mounted sync=always.  Calling zil_commit
whenever we delete a file absolutely wrecks performance and shouldn't
be needed for on-disk correctness in normal zfs semantics unless I
terribly misunderstand something, so we must be doing something wrong
with the in-memory state if we seem to need this.

Do you have a test case that can trigger the problem?