xfs: rework xlog_state_do_callback()

mainline-inclusion
from mainline-v5.14-rc4
commit 8bb92005
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4V7IK
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8bb92005b0e4682a6e5dad131c5f3636c7d56dc1



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Clean it up a bit by factoring and rearranging some of the code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Lihong Kou <koulihong@huawei.com>
Reviewed-by: guoxuenan <guoxuenan@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>