I have been using fedora 35. It was running fine until today when I was going to edit some files but it could not be saved. All file has become read-only. I made a reboot which changed nothing. Upon attemting for up-gradation by sudo dnf upgrade --refresh , it is showing the following error.
The most likely cause of this is a failing hard drive, so the kernel mounts it as read only to give yourself a chance to get data off before it fully dies. Usually there will be clues about it in dmesg.