(somehow this message did not make it to the list) Hi, After upgrading from linux 3.17.0 to 3.18.0-rc2, I cannot mount my btrfs partition any more. It's just one btrfs partition, no raid, no compression, no fancy mount options: # mount -t btrfs -o ro /dev/sda6 /usr/local/ mount: wrong fs type, bad option, bad superblock on /dev/sda6, [...] BTRFS: suspicious number of devices: 72057594037927936 BTRFS: super offset mismatch 1099511627776 != 65536 BTRFS: superblock contains fatal errors BTRFS: open_ctree failed The only thing fancy may be the machine: PowerBook G4 (powerpc 32 bit), running Debian/Linux (stable). The message comes from the newly added fs/btrfs/disk-io.c: if (sb->num_devices > (1UL << 31)) printk(KERN_WARNING "BTRFS: suspicious number of devices: %llu\n", sb->num_devices); And 72057594037927936 is 2^56, so maybe there's an endianess problem here? Some details below, please let me know what other details may be needed. Going back to 3.17 now... Thanks, Christian. # file -Ls /dev/sda6 /dev/sda6: sticky BTRFS Filesystem sectorsize 4096, nodesize 4096, leafsize 4096) # btrfsck /dev/sda6 checking extents checking fs roots checking root refs found 2035929088 bytes used err is 0 total csum bytes: 1886920 total tree bytes: 102936576 total fs tree bytes: 94441472 btree space waste bytes: 30875964 file data blocks allocated: 1932992512 referenced 1932849152 Btrfs Btrfs v0.19 # echo $? 0 -- BOFH excuse #427: network down, IP packets delivered via UPS -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html