vfs: Remove unnecessary flushing of block devices
authorJan Kara <jack@suse.cz>
Tue, 3 Jul 2012 14:45:33 +0000 (16:45 +0200)
committerAl Viro <viro@zeniv.linux.org.uk>
Sun, 22 Jul 2012 19:58:53 +0000 (23:58 +0400)
commitd0e91b13eb34d449922124c34f8a05e498daa089
tree59124b824744aaf0657c57c986ed77c42d6fc748
parenta8c7176b6ded413d5044a00f1d05477b95a6d7ad
vfs: Remove unnecessary flushing of block devices

It is not necessary to write block devices twice. The reason why we first did
flush and then proper sync is that
  for_each_bdev() {
    write_bdev()
    wait_for_completion()
  }
is much slower than
  for_each_bdev()
    write_bdev()
  for_each_bdev()
    wait_for_completion()
when there is bigger amount of data. But as is seen in the above, there's no real
need to scan pages and submit them twice. We just need to separate the submission
and waiting part. This patch does that.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/sync.c