How do I merge the 8 GB of "free space" on Macintosh HD under Logical volume group into Macintosh HD? I did some partitioning using bootcamp 6.0 to install windows that left a 8 GB of free space with cannot be restored normally, How do I get it back? The diskutils cs list shows:

Last login: Sat Jul 29 16:51:28 on ttys000
AssASSiNxGAs-MacBook-Air:~ AssASSiNxgA$ diskutil cs list
CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group F57AE880-8554-4F18-B1FC-6291360C2257
    =========================================================
    Name:         Macintosh HD
    Status:       Online
    Size:         120368205824 B (120.4 GB)
    Free Space:   8019730432 B (8.0 GB)
    |
    +-&lt; Physical Volume 1A135E2C-54E5-4AA4-9FFA-3444B0E81A47
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     120368205824 B (120.4 GB)
    |
    +-&gt; Logical Volume Family 87ABD6CD-2981-4971-9724-4D7F3CBC95AC
        ----------------------------------------------------------
        Encryption Type:         None
        |
        +-&gt; Logical Volume FD192884-33A4-43CB-86A6-9CE4E58B3B92
            ---------------------------------------------------
            Disk:                  disk1
            Status:                Online
            Size (Total):          111996153856 B (112.0 GB)
            Revertible:            Yes (no decryption required)
            LV Name:               Macintosh HD
            Volume Name:           Macintosh HD
            Content Hint:          Apple_HFS
AssASSiNxGAs-MacBook-Air:~ AssASSiNxgA$ 


My Disk Utility looks like this:
Resizing a Logical Volume in a larger Logical Volume Group with some free space is done with the undocumented coreStorage-verb resizeVolume:

diskutil cs resizeVolume lvUUID size


with lvUUID: UUID of the Logical Volume (the UUIDs are retrievable by entering diskutil cs list) and size (size in b/k/m/g/t | 0 | R)

0 and R are magical sizes and try to maximize the size of the Logical Volume (depends on the system version - doesn't work in all macOS systems).

In your case I recommend:

diskutil cs resizeVolume FD192884-33A4-43CB-86A6-9CE4E58B3B92 120128m


If you get an error disk to small (or similar) choose slightly smaller sizes like 120064m or 120000m until you are successful. The final size of the expanded Logical Volume is slightly smaller than the underlying Physical Volume: some space on the PV is required to store CoreStorage meta data.

Example:

Fusion Drive 3.12 TB:

combined PV size:  3120722 MB
LV size:           3106192 MB
∆ (PV-LV) size:      14530 MB (= 14.5 GB or 0.47%!)