xfs: avoid extra cache flushes for multi-device file systems in xfs_fsync

When xlog_force_lsn sets log_flushed, it has just called xlog_force_iclog
through xlog_force_and_check_iclog, which sets XLOG_ICL_NEED_FLUSH before
writing out the head iclog.  This means that we already flushed the log,
data, and (with the recent fix) RT devices before writing out the iclog
start record and no extra cache flushed is required.

This optimizes the external log case, and fixes a performance regression
due to double RT dev flushes with "xfs: also flush the RT device cache in
xlog_write_iclog".

The explicit flush of the data that the device resides on when no iclog
was written out is still required.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

0 files changed, 0 insertions, 0 deletions