On 2019/6/28 下午4:00, Erik Jensen wrote: >> So it's either the block layer reading some wrong from the disk or btrfs >> layer doesn't do correct endian convert. > > My ARM board is running in little endian mode, so it doesn't seem like > endianness should be an issue. (It is 32-bits versus my desktop's 64, > though.) I've also tried exporting the drives via NBD to my x86_64 > system, and that worked fine, so if the problem is under btrfs, it > would have to be in the encryption layer, but fsck succeeding on the > ARM board would seem to rule that out, as well. > >> Would you dump the following data (X86 and ARM should output the same >> content, thus one output is enough). >> # btrfs ins dump-tree -b 17628726968320 /dev/dm-3 >> # btrfs ins dump-tree -b 17628727001088 /dev/dm-3 > > Attached, and also 17628705964032, since that's the block mentioned in > my most recent mount attempt (see below).
The trees are completely fine. So it should be something else causing the problem. > >> And then, for the ARM system, please apply the following diff, and try >> mount again. >> The diff adds extra debug info, to exam the vital members of a tree block. >> >> Correct fs should output something like: >> BTRFS error (device dm-4): bad tree block start, want 30408704 have 0 >> tree block gen=4 owner=5 nritems=2 level=0 >> csum: >> a304e483-0000-0000-0000-00000000000000000000-0000-0000-0000-000000000000 >> >> The csum one is the most important one, if there aren't so many zeros, >> it means at that timing, btrfs just got a bunch of garbage, thus we >> could do further debug. > > [ 131.725573] BTRFS info (device dm-1): disk space caching is enabled > [ 131.731884] BTRFS info (device dm-1): has skinny extents > [ 133.046145] BTRFS error (device dm-1): bad tree block start, want > 17628705964032 have 2807793151171243621 > [ 133.055775] tree block gen=7888986126946982446 > owner=11331573954727661546 nritems=4191910623 level=112 > [ 133.065661] csum: > 416a456c-1e68-dbc3-185d-aaad410beaef5493ab3f-3cb9-4ba1-2214-b41cba9656fc Completely garbage here, so I'd say the data we got isn't what we want. > [ 133.108383] BTRFS error (device dm-1): bad tree block start, want > 17628705964032 have 2807793151171243621 > [ 133.117999] tree block gen=7888986126946982446 > owner=11331573954727661546 nritems=4191910623 level=112 > [ 133.127756] csum: > 416a456c-1e68-dbc3-185d-aaad410beaef5493ab3f-3cb9-4ba1-2214-b41cba9656fc But strangely, the 2nd try still gives us the same result, if it's really some garbage, we should get some different result. > [ 133.136241] BTRFS error (device dm-1): failed to verify dev extents > against chunks: -5 You can try to skip the dev extents verification by commenting out the btrfs_verify_dev_extents() call in disk-io.c::open_ctree(). It may fail at another location though. The more strange part is, we have the device tree root node read out without problem. Thanks, Qu > [ 133.166165] BTRFS error (device dm-1): open_ctree failed > > I copied some files over last time I had it mounted on my desktop, > which may be why it's now failing at a different block. > > Thanks! >
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