fs: f2fs: initialize fsdata in pagecache_write()

stable inclusion
from stable-v5.10.173
commit 6be349d7388f3af7957dc6c7e241dc92a969fb38
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8BFR3

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6be349d7388f3af7957dc6c7e241dc92a969fb38



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[ Upstream commit b1b98967 ]

When aops->write_begin() does not initialize fsdata, KMSAN may report
an error passing the latter to aops->write_end().

Fix this by unconditionally initializing fsdata.

Suggested-by: Eric Biggers <ebiggers@kernel.org>
Fixes: 95ae251f ("f2fs: add fs-verity support")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>