Hello list, I hit a funny BIOS bug the other day where the BIOS suddenly sets a HPA on a random hard disk, leaving only the first 33 MB accessible. That disk had one device of a multi-device btrfs on it in my case. (With dm-crypt/LUKS in between, no partitioning or LVM.) The reason I'm writing to you is that btrfs apparently didn't care at all. It didn't complain, and it certainly didn't consider "Uhm, maybe I should stop writing to a file system that mostly doesn't exist anymore." The only errors I saw in dmesg were from the lower block device level: someone trying to read or write beyond the end of a device. An error btrfs apparently didn't mind. It took me a while to figure out what had happened, during which time btrfsck and the btrfs kernel part worked together to pretty much totally trash the fs. (I'm still trying a few things, but I'm not hopeful. Hold the default backup rant, I can in fact recover anything that was on this from elsewhere, I think.) So, I think during mount, btrfs should check the reported size of the block device, and if it's significantly smaller than fs metadata implies it must be, mount degraded or read-only or not at all. And mostly, complain. Loudly. This was on Debian's linux-image-3.1.0-1-amd6 at version 3.1.6-1. Other ways this could happen than HPA are LVM or partitioning. Maik -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
