Gfilui

Apologies for a basic question about Ubuntu from a novice. My laptop has one SSD, where Ubuntu 16.04LTS is installed, and one HDD. They both have several partitions. Yesterday, I tried to recover files from my old corrupt flash drive mounted as sdc1. I used several tools, but I suspect that the crucial thing was the following command:

ddrescue -f -r3 /dev/sdc1 /dev/sdb4 logfile

After I ran it, one of the HDD partitions appeared to be repartitioned and nautilus started showing boxes with arrows near my HDD partition labels. Now, when I reboot, my HDD partitions do not mount automatically. I only see the empty desktop and can launch only one terminal at a time, as they all flock in the upper-left corner of the desktop and can't be moved from there.

lsblk gives the following:

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 119.2G 0 disk 
sda1 8:1 0 600M 0 part /boot/efi
sda2 8:2 0 3G 0 part 
sda3 8:3 0 83.9G 0 part 
sda4 8:4 0 31.8G 0 part [SWAP]
sdb 8:16 0 931.5G 0 disk 
sdb1 8:17 0 200G 0 part 
sdb2 8:18 0 500G 0 part 
sdb3 8:19 0 200G 0 part 
sdb4 8:20 0 31.5G 0 part 
sdc 8:32 1 29.1G 0 disk 
sdc1 8:33 1 29.1G 0 part /media/me/TOSHIBA
loop0 7:0 0 81.7M 1 loop /snap/core/4017
loop1 7:1 0 81.6M 1 loop /snap/core/4110
loop2 7:2 0 81.3M 1 loop /snap/core/3887

Here sda is my SSD and sdb is my HDD. As you see, the HDD partitions are not mounted.

Here is blkid:

/dev/sda1: LABEL="ESP" UUID="0AEC-8283" TYPE="vfat" PARTLABEL="EFI system partition" PARTUUID="3ae1181e-c506-4254-be93-f8ebb7487763"
/dev/sda2: LABEL="OS" UUID="6810-7989" TYPE="vfat" PARTLABEL="Basic data partition" PARTUUID="6aefe6a8-9e57-4f58-8fed-e4c87cb0890e"
/dev/sda3: LABEL="UBUNTU" UUID="64ef968d-8488-49b1-8dde-a0829168b76f" TYPE="ext4" PARTUUID="b61d10c6-e5a8-456b-bf9c-19bff4b97c66"
/dev/sda4: UUID="181a3feb-93f6-4e98-8583-52a683f658bc" TYPE="swap" PARTUUID="e0c61132-4bc0-4089-be6f-e035b89e404a"
/dev/sdb1: LABEL="C" UUID="16D1E84B6E1AEFF3" TYPE="ntfs" PARTUUID="e1d5874f-01"
/dev/sdb2: LABEL="D" UUID="329D74C657FEB321" TYPE="ntfs" PARTUUID="e1d5874f-02"
/dev/sdb3: LABEL="F" UUID="4E0068F541357DFD" TYPE="ntfs" PARTUUID="e1d5874f-03"
/dev/sdb4: UUID="64A7-9503" TYPE="vfat" PARTUUID="e1d5874f-04"
/dev/loop0: TYPE="squashfs"
/dev/loop1: TYPE="squashfs"
/dev/loop2: TYPE="squashfs"

/dev/sdb4 appears to be repartitioned by ddrescue.

Here is fstab:

<file system> <mount point> <type> <options> <dump> <pass> 
/ was on /dev/sda3 during installation 
UUID=64ef968d-8488-49b1-8dde-a0829168b76f / ext4 errors=remount-ro 0 1
/boot/efi was on /dev/sda1 during installation 
UUID=0AEC-8283 /boot/efi vfat umask=0077 0 1 
swap was on /dev/sda4 during installation 
UUID=181a3feb-93f6-4e98-8583-52a683f658bc none swap sw 0 0 

It is easy to fix each time as nautilus still sees my partitions and they mount after I click on their icons.

The only abnormal thing which I see in gparted is the warning mark at /dev/sdb4 saying

30.55 GiB of unallocated space within the partition. To grow the file system to fill the partition, select the partition and choose the menu item: Partition->Check"

Besides, this partition is fat32 while the other HDD partitions are ntfs. I don't remember if they were these originally or changed by ddrescue.

Now, I think that I can easily fix all this in the sense that I can repartition /dev/sdb4 and edit fstab. However, being a novice and not fully understanding what's going on, I would rather prefer to roll all this back to where it was before the corruption.

The ddrescue logfile follows:

Rescue Logfile. Created by GNU ddrescue version 1.19
Command line: ddrescue -f -r3 /dev/sdc1 /dev/sdb4 logfile
Start time: 2018-03-04 01:39:04
Current time: 2018-03-04 01:41:40
Finished
current_pos current_status
0x102FBE00 +
 pos size status
0x00000000 0x102BC000 +
0x102BC000 0x00040000 -
0x102FC000 0x2D100000 +

dmesg says EXT4-fs (sda3): re-mounted. Opts: errors=remount-ro

What exactly could have happened? I think it was more than just repartitioning of /dev/sdb4. Why are the partitions not auto-mounting now? How can I roll this back? Will everything restore to normal if I do Partition->Check on /dev/sdb4 as gparted suggests?