ext2: Fix ki_pos update for DIO buffered-io fallback case

stable inclusion
from stable-v6.6.5
commit c5b09a65b4bac4e1c31ce94d3cdf5ea547ea1ff5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8N21P

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c5b09a65b4bac4e1c31ce94d3cdf5ea547ea1ff5



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commit 8abc712ea4867a81c860853048f24e511bbc20f2 upstream.

Commit "filemap: update ki_pos in generic_perform_write", made updating
of ki_pos into common code in generic_perform_write() function.
This also causes generic/091 to fail.
This happened due to an in-flight collision with:
fb5de435 ("ext2: Move direct-io to use iomap"). I have chosen fixes tag
based on which commit got landed later to upstream kernel.

Fixes: 182c25e9 ("filemap: update ki_pos in generic_perform_write")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <d595bee9f2475ed0e8a2e7fb94f7afc2c6ffc36a.1700643443.git.ritesh.list@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>