Today, after 77 days of uptime, my R7800 router experienced a fault. According to the log, there was a "usb disconnect" (I only have a SATA SSD connected via USB adapter, and it was successfully remounted after that), and some i/o errors on mtdblock0 and mtdblock1 devices.
Just in case, I rebooted the router. It seems to work now (and I have a configuration backup), but there is this ugly thing in the dmesg:
[ 12.327252] kmodloader: done loading kernel modules from /tmp/overlay/upper/etc/modules-boot.d/*
[ 12.348715] blk_update_request: I/O error, dev mtdblock0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 0
[ 12.349655] blk_update_request: I/O error, dev mtdblock0, sector 8 op 0x0:(READ) flags 0x80700 phys_seg 3 prio class 0
[ 12.359279] blk_update_request: I/O error, dev mtdblock0, sector 16 op 0x0:(READ) flags 0x80700 phys_seg 2 prio class 0
[ 12.391237] blk_update_request: I/O error, dev mtdblock0, sector 24 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[ 12.392161] blk_update_request: I/O error, dev mtdblock0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ 12.400877] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[ 12.430776] blk_update_request: I/O error, dev mtdblock1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 2 prio class 0
[ 12.431827] blk_update_request: I/O error, dev mtdblock1, sector 8 op 0x0:(READ) flags 0x80700 phys_seg 2 prio class 0
[ 12.441398] blk_update_request: I/O error, dev mtdblock1, sector 16 op 0x0:(READ) flags 0x80700 phys_seg 2 prio class 0
[ 12.452116] blk_update_request: I/O error, dev mtdblock1, sector 24 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[ 12.491084] blk_update_request: I/O error, dev mtdblock1, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ 12.491109] Buffer I/O error on dev mtdblock1, logical block 0, async page read
Should I buy a new router, or is there any way to remap these bad sectors? AFAIK ubifs is supposed to be able to do that, but I don't know how to trigger that.