Comment 2 for bug 1851451

I'd suggest checking your hardware (esp. SMART status of ATA drives, cables etc)

I see in your logs the following :-

[ 6124.754413] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x50000 action 0x6 frozen
[ 6124.754428] ata1: SError: { PHYRdyChg CommWake }
[ 6124.754437] ata1.00: failed command: WRITE DMA
[ 6124.754455] ata1.00: cmd ca/00:08:18:e0:64/00:00:00:00:00/e0 tag 18 dma 4096 out
                        res 40/00:00:00:01:80/00:00:00:00:00/00 Emask 0x4 (timeout)
[ 6124.754462] ata1.00: status: { DRDY }
[ 6124.754472] ata1: hard resetting link
[ 6125.068646] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 320)
[ 6125.093229] ata1.00: configured for UDMA/133
[ 6125.103327] ahci 0000:00:17.0: port does not support device sleep
[ 6125.103407] ata1: EH complete
[ 6125.103774] ata1.00: Enabling discard_zeroes_data

NOTE: SMART doesn't detect everything, but it's where I'd start, beyond validating your backups in case this is warning of a failing component/device. This may not be your only issue though.