File privileges problem on USB thumbdrive

[Bret Busby]

On 17/08/2020, Colin Law <clanlaw at gmail.com> wrote:
> On Sun, 16 Aug 2020 at 20:10, Bret Busby <bret.busby at gmail.com> wrote:
>>
>> Hello.
>>
>> This applies equally to UbuntuMATE 20.04.x and 16.04.x .
>>
>> I have a USB thumbdrive, which is formatted as FAT32.
>>
>> I want to move the files written to it, to another medium, so as to
>> reuse the thumbdrive for writing.
>>
>> I have previously done this, with this thumbdrive, and, with other
>> thumbdrives of the same model, capacity (128GB), and manufacturer.
>>
>> However, now, whilst file managers (caja and PCmanFM) show me, as the
>> owner of the files, with Read and write folder access, no file access
>> privilege is shown in the caja file manager, and, I can not use cut
>> (and thence paste to another destination) or rename functionality on
>> the files, and, trying to use chmod 777 and sudo chmod 777 , both
>> return the error "file system is read only".
>>
>> ls  -l shows
>> -rw -r--r--
>> for the files.
>>
>> As I am supposed to be able, as the shown owner of the files, both
>> read and write to, the files, why does the operating system designate
>> them as read-only, and, how do I overcome this?
>
> Apologies in advance, but I have to ask whether you have checked that
> the write protect switch on the drive (if there is one) is in the
> correct state?
>
> Otherwise are you able to write to it on a Windows system?  It is
> possible that it is broken.
>
> It might be worth watching the log while you plug it in, it might
> indicate why it is read only.
> sudo journalctl -f
> or
> sudo tail -f /var/log/syslog
>
> Colin
>

Third attempt at sending - gmail told me that the second attempt had
been sent, but, it disappeared again - no copy in my sent mail, no
copy anywhere, even with a BCC to me.

"
Mon Aug 17 05:51:37 bret at bret-MD34045-2521:~$sudo tail -f /var/log/syslog
Aug 17 05:52:19 bret-MD34045-2521 kernel: [782634.497686] sd 8:0:0:0:
Attached scsi generic sg4 type 0
Aug 17 05:52:19 bret-MD34045-2521 kernel: [782634.498301] sd 8:0:0:0:
[sdd] 245760000 512-byte logical blocks: (126 GB/117 GiB)
Aug 17 05:52:19 bret-MD34045-2521 kernel: [782634.498563] sd 8:0:0:0:
[sdd] Write Protect is off
Aug 17 05:52:19 bret-MD34045-2521 kernel: [782634.498564] sd 8:0:0:0:
[sdd] Mode Sense: 23 00 00 00
Aug 17 05:52:19 bret-MD34045-2521 kernel: [782634.498736] sd 8:0:0:0:
[sdd] Write cache: disabled, read cache: disabled, doesn't support DPO
or FUA
Aug 17 05:52:19 bret-MD34045-2521 kernel: [782634.527747]  sdd: sdd1
Aug 17 05:52:19 bret-MD34045-2521 kernel: [782634.528525] sd 8:0:0:0:
[sdd] Attached SCSI removable disk
Aug 17 05:52:20 bret-MD34045-2521 kernel: [782635.879551] FAT-fs
(sdd1): Volume was not properly unmounted. Some data may be corrupt.
Please run fsck.
Aug 17 05:52:20 bret-MD34045-2521 systemd[1]: Finished Clean the
/media/bret/10C0-C930 mount point.
Aug 17 05:52:21 bret-MD34045-2521 udisksd[1146]: Mounted /dev/sdd1 at
/media/bret/10C0-C930 on behalf of uid 1000
Aug 17 05:52:34 bret-MD34045-2521 tracker-store[1066020]: OK
Aug 17 05:52:34 bret-MD34045-2521 systemd[1720]:
tracker-store.service: Succeeded.
Aug 17 05:53:04 bret-MD34045-2521 kernel: [782679.480574] [UFW BLOCK]
IN=wlp2s0 OUT= MAC=01:00:5e:00:00:01:50:d4:f7:70:10:95:08:00
SRC=192.168.1.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0x00 TTL=1 ID=0 DF
PROTO=2
Aug 17 05:53:09 bret-MD34045-2521 kernel: [782684.318747] FAT-fs
(sdd1): error, fat_bmap_cluster: request beyond EOF (i_pos 0)
Aug 17 05:53:09 bret-MD34045-2521 kernel: [782684.318749] FAT-fs
(sdd1): Filesystem has been set read-only
Aug 17 05:53:29 bret-MD34045-2521 kernel: [782704.617339] FAT-fs
(sdd1): error, fat_bmap_cluster: request beyond EOF (i_pos 960514)
Aug 17 05:53:29 bret-MD34045-2521 dbus-daemon[1743]: [session uid=1000
pid=1743] Activating via systemd: service
name='org.freedesktop.Tracker1' unit='tracker-store.service' requested
by ':1.2' (uid=1000 pid=1740 comm="/usr/libexec/tracker-miner-fs "
label="unconfined")
Aug 17 05:53:29 bret-MD34045-2521 systemd[1720]: Starting Tracker
metadata database store and lookup manager...
Aug 17 05:53:29 bret-MD34045-2521 dbus-daemon[1743]: [session uid=1000
pid=1743] Successfully activated service 'org.freedesktop.Tracker1'
Aug 17 05:53:29 bret-MD34045-2521 systemd[1720]: Started Tracker
metadata database store and lookup manager.
^C
"

-- 
Bret Busby
Armadale
West Australia
..............