Hi Qu, At the end of my first initial post, I mentioned that I finally was able to mount the volume using: mount -o usebackuproot,ro /dev/sdh2 /mnt/data The chunk tree and super blocks dumps were taken after that. Now I noticed that I was able to mount the volume without special options (same kernel version). YAY! ☺ Could it be that the "usebackuproot,ro" mount options already fixed the issue? Cheers, Patrick On Sat, 2019-08-24 at 21:24 +0800, Qu Wenruo wrote: > On 2019/8/24 下午8:05, Patrick Dijkgraaf wrote: > > Thanks for the quick reply! > > See responses inline. > > > > On Sat, 2019-08-24 at 19:01 +0800, Qu Wenruo wrote: > > > On 2019/8/24 下午2:48, Patrick Dijkgraaf wrote: > > > > Hi all, > > > > > > > > My server hung this morning, and I had to hard-reset is. I did > > > > not > > > > apply any updates. After the reboot, my FS won't mount: > > > > > > > > [Sat Aug 24 08:16:31 2019] BTRFS error (device sde2): > > > > super_total_bytes > > > > 92017957797888 mismatch with fs_devices total_rw_bytes > > > > 184035915595776 > > > > [Sat Aug 24 08:16:31 2019] BTRFS error (device sde2): failed to > > > > read > > > > chunk tree: -22 > > > > [Sat Aug 24 08:16:31 2019] BTRFS error (device sde2): > > > > open_ctree > > > > failed > > > > > > > > However, running btrfs rescue shows: > > > > root@cornelis ~]# btrfs rescue fix-device-size /dev/sdh2 > > > > No device size related problem found > > > > > > That's strange. > > > > > > Would you please dump the chunk tree and super blocks? > > > # btrfs ins dump-super -fFa /dev/sdh2 > > > > See: > > https://pastebin.com/f5Wn15sx > > > > Did a quick calculation, from your fi show result, it's 83.72TiB, > thus > the super total_bytes is correct. > > It's the kernel doing incorrect calculation for its > fs_devices->total_rw_bytes. > > This matches the output of dump-super. No wonder why btrfs-progs > refuse > to fix. > > > # btrfs ins dump-tree -t chunk /dev/sdh2 > > > > This output is too large for pastebin. The output is > > viewable/downloadable here: > > https://kwek.duckstad.net/tree.txt > > > > This also proves your chunk tree is CORRECT! > The sum of all devices is 92017957797888, which matches with super > block. > [...] > > > The simplest way to fix it is to just update the > > > > Nice teaser! 😉 What should I update? > > Sorry, I meant to say just update the "superblock", but it turns out, > it's something wrong with your kernel. Probably some old bug we fixed > before. > > Would you try to use latest ARCH kernel from an Archiso to try to > mount > it RO (just to be safe)? > > I checked latest v5.3-rc kernels, haven't found an obvious problem > with > the fs_devices->total_rw_bytes update routines. > > So it may be an old bug which is already fixed. > > Thanks, > Qu > > > > Thanks, > > > Qu > > > > Other info: > > > > [root@cornelis ~]# uname -r > > > > 4.18.16-arch1-1-ARCH > > > > > > > > I was able to mount is using: > > > > [root@cornelis ~]# mount -o usebackuproot,ro /dev/sdh2 > > > > /mnt/data > > > > > > > > Now updating my backup, but I REALLY hope to get this fixed on > > > > the > > > > production server! > > > > > > > >
