LU-18218 mdd: changelog specific write function

LU-18218 mdd: changelog specific write function

Don't use a general llog_osd_write_rec() for a changelog,
it has too many synchronisation for a consistency, and additional
complexity for a remote writes. And as a result changelog enabling
slowdowns MDT IO performance by 3x. The main idea of this patch is
parallel writers to a local file, some inconsistence would be
handled by a reader.

The lgh_hdr_mutex protects modifications at memory, there is no
need to cover dt_record_write() by it. Since write/cancel protects
by lgh_lock mutex. Let's change lgh_hdr_mutex to a spinlock.

Perfomance results for mdtest mean at cluster
Changelog		no	basic	patch	diff %
Directory creation	90152	32800	63827	94
Directory removal	96900	32928	61220	85
File creation		116109	52318	82698	58
File removal		119260	42845	80557	88

HPE-bug-id: LUS-11970
Signed-off-by: Alexander Boyko <alexander.boyko@hpe.com>
Change-Id: Icbe26e1198630dc72f4dfd9fca59718076579245
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56342
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexey Lyashkov <alexey.lyashkov@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>