On Tue, May 28, 2019 at 03:39:36PM -0300, Cesar Strauss wrote: > Hello, > > After a BTRFS partition becoming read-only under use, it cannot be > mounted anymore. > > The output is: > > # mount /dev/sdb5 /mnt/disk1 > mount: /mnt/disk1: wrong fs type, bad option, bad superblock on > /dev/sdb5, missing codepage or helper program, or other error. > > Kernel output: > [ 2042.106654] BTRFS info (device sdb5): disk space caching is enabled > [ 2042.799537] BTRFS critical (device sdb5): corrupt leaf: root=2 > block=199940210688 slot=31, unexpected item end, have 268450090 > expect 14634 You have bad RAM. The item end it's got on the disk: >>> hex(268450090) '0x1000392a' The item end it should have (based on the other items and their lengths and positions): >>> hex(14634) '0x392a' The good checksum on the block (it hasn't complained about the csum, so it's good) indicates that the corruption happened in memory at some point. The bit-flip in the data would strongly suggest that it's caused by a stuck memory cell -- i.e. bad hardware. Run memtest86 for a minimum of 8 hours (preferably 24) and see what shows up. Then fix the hardware. Hugo. > [ 2042.807879] BTRFS critical (device sdb5): corrupt leaf: root=2 > block=199940210688 slot=31, unexpected item end, have 268450090 > expect 14634 > [ 2042.807947] BTRFS error (device sdb5): failed to read block groups: -5 > [ 2042.832362] BTRFS error (device sdb5): open_ctree failed > > # btrfs check /dev/sdb5 > Opening filesystem to check... > incorrect offsets 14634 268450090 > incorrect offsets 14634 268450090 > incorrect offsets 14634 268450090 > incorrect offsets 14634 268450090 > ERROR: cannot open file system > > Giving -s and -b options to "btrfs check" made no difference. > > The usebackuproot mount option made no difference. > > "btrfs restore" was successful in recovering most of the files, > except for a couple instances of "Error copying data". > > System information: > > OS: Arch Linux > > $ uname -a > Linux rescue 5.1.4-arch1-1-ARCH #1 SMP PREEMPT Wed May 22 08:06:56 > UTC 2019 x86_64 GNU/Linux > > $ btrfs --version > btrfs-progs v5.1 > > I have since updated the kernel, with no difference: > > $ uname -a > Linux rescue 5.1.5-arch1-2-ARCH #1 SMP PREEMPT Mon May 27 03:37:39 > UTC 2019 x86_64 GNU/Linux > > Before making any recovery attempts, or even restoring from backup, > I would like to ask for the best option to proceed. > > Thanks, > > Cesar -- Hugo Mills | You've read the project plan. Forget that. We're hugo@... carfax.org.uk | going to Do Stuff and Have Fun doing it. http://carfax.org.uk/ | PGP: E2AB1DE4 | Jeremy Frey
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