ext4: fix leaking uninitialized memory in fast-commit journal

stable inclusion
from stable-v5.10.163
commit b8b7922374b00a44137e5bcdd46ef86c8b065f27
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7PJ9N

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b8b7922374b00a44137e5bcdd46ef86c8b065f27



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[ Upstream commit 594bc43b ]

When space at the end of fast-commit journal blocks is unused, make sure
to zero it out so that uninitialized memory is not leaked to disk.

Fixes: aa75f4d3 ("ext4: main fast-commit commit path")
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221106224841.279231-4-ebiggers@kernel.org


Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: zhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>