fsck.f2fs: Split build_segment_manager() to speed up auto-fix

Speed up fsck in auto-fix mode by splitting
build_segment_manager() into two disjoint parts:
	early_build_segment_manager(), and
	late_build_segment_manager(),
where in some cases (when !need_fsync_data_record(), or cannot
find_fsync_inode()), late_build_segment_manager() won't be needed in
auto-fix mode.  This speeds up a little bit in those cases.

Bug: 157471256
Test: on an arbitrary f2fs image (before and after this patch)
Signed-off-by: Robin Hsu <robinhsu@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Change-Id: I0fd9753c169b71ca1a91da27723d4d95ca6998fe
Merged-In: I1dce1039bc01641f7c33875a1cfe20943cdc42ac
2 files changed