jbd2: optimize jbd2_journal_force_commit

Current implementation of jbd2_journal_force_commit() is suboptimal because
result in empty and useless commits. But callers just want to force and wait
any unfinished commits. We already have jbd2_journal_force_commit_nested()
which does exactly what we want, except we are guaranteed that we do not hold
journal transaction open.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
configs: p700 upstream
Revert "cleanup"

This reverts commit e9df054a21ca1a838036b191c5f4bc2b66fbeaf2.
Revert "update exfat"

This reverts commit a77acb6dc05236cc9572edfc421233359d094761.
Revert "Revert "update exfat""

This reverts commit 06677cc8b2b36913b5d78d566a5a4643ee20ddd8.
Revert "Revert "cleanup""

This reverts commit 528ac6c74f756bce567aa4dfcad1d2a3164a6f73.
AIO Optimization compatibility fixup
Merge pull request #9 from pac-lg/wip

Wip