udf: Fix data integrity writeout issues

udf: Fix data integrity writeout issues

UDF could fail to properly write out inode on fsync(2) due to races
with WB_SYNC_NONE writeback. Several racing fsyncs could also result in
some fsync returning earlier than all metadata buffers were properly
persisted.

Fix all these issues by using new .sync_inode_metadata method which
makes sure all inode related metadata is written to disk during any
WB_SYNC_ALL writeback.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260727104923.3828017-30-jack@suse.cz
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>