Hello Jean-Denis, See comments inline. Friday, November 13, 2020, 6:25:15 AM, you wrote: > Hi list, > I have a RAID1 Btrfs (on sdb and sdc) behind bcache (on nvme0n1p4): What's the cache mode? Writeback, writethrough, writearound? You can execute 'cat /sys/block/bcache0/bcache/cache_mode' and 'cat /sys/block/bcache1/bcache/cache_mode' to find out. > [jdg@tiare ~]$ lsblk -o NAME,UUID,SIZE,MOUNTPOINT > NAME UUID SIZE MOUNTPOINT > sdb 8ae3c26b-6932-4dad-89bc-569ae2c74366 3,7T > L-bcache1 c5b8386b-b81d-4473-9340-7b8a74fc3a3c 3,7T > sdc 7ccac426-dc8c-4cb3-9e64-13b1cf48d4bf 3,7T > L-bcache0 c5b8386b-b81d-4473-9340-7b8a74fc3a3c 3,7T > nvme0n1 119,2G > +-nvme0n1p1 1725-D2D0 512M /boot/efi > +-nvme0n1p2 d3cc080c-0c3f-4191-a25d-7c419e00316a 40G / > +-nvme0n1p3 572b43a3-7690-4daa-beeb-d1c030f194e8 16G [SWAP] > L-nvme0n1p4 a3ed0098-36b4-46a6-8e38-efe9b9a94e52 62,8G <- bcache > The Btrfs filesystem is used for /home (one subvolume per user). > An error happened during the nightly backup on nvme0 (see below) and > Btrfs went readonly. After reboot, it refused to mount. > I'm on Fedora-32 with kernel-5.9.7, and I compiled latest btrfs-progs: > [root@tiare btrfs-progs-5.9]# ./btrfs -v check /dev/bcache0 > Opening filesystem to check... > parent transid verify failed on 3010317451264 wanted 29647859 found 29647852 > parent transid verify failed on 3010317451264 wanted 29647859 found 29647852 > parent transid verify failed on 3010317451264 wanted 29647859 found 29647852 > Ignoring transid failure > ERROR: could not setup extent tree > ERROR: cannot open file system > I have restored from backups on a different disk, but still, I would be > interested in trying to restore the broken filesystem. > I have posted this message on Btrfs mailing list already. The advice was > to seek for help here: what should I try? Detach both HDD from bcache? > Create loopdev on both HDD with losetup -o 8192, then try to mount? You could try to detach the *cache* from the bcache devices, and then try to use the bcache devices as before; it should be possible and harmless, *unless* the cache mode is "writeback". If it's "writeback", things are more complicated, and I'll leave them to more experienced people around. For instructions on how to detach the cache, see, for example, https://unix.stackexchange.com/a/115808/82477 (it's just the first thing that I found by googling, and it seems to match what I did when detaching myself). IMPORANT: The kernel logs below indicate that bcache failed to do IO on the cache device. It could be a hardware problem with your NVMe device, so I suggest you look at its SMART, ASAP. > /var/log/messages : > Nov 11 00:24:28 tiare kernel: nvme nvme0: I/O 0 QID 5 timeout, aborting > Nov 11 00:24:28 tiare kernel: nvme nvme0: I/O 1 QID 5 timeout, aborting > Nov 11 00:24:28 tiare kernel: nvme nvme0: I/O 2 QID 5 timeout, aborting > Nov 11 00:24:28 tiare kernel: nvme nvme0: Abort status: 0x0 > Nov 11 00:24:28 tiare kernel: nvme nvme0: I/O 3 QID 5 timeout, aborting > Nov 11 00:24:28 tiare kernel: nvme nvme0: I/O 4 QID 5 timeout, aborting > ... > Nov 11 00:24:58 tiare kernel: nvme nvme0: I/O 0 QID 5 timeout, reset > controller > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 153333328 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_io_errors() nvme0n1p4: > IO error on reading from > cache, recovering. > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 153333344 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_io_errors() nvme0n1p4: > IO error on reading from cache, recovering. > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 153333384 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_io_errors() nvme0n1p4: > IO error on reading from cache, recovering. > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 153333424 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_io_errors() nvme0n1p4: > IO error on reading from cache, recovering. > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 153333464 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_io_errors() nvme0n1p4: > IO error on reading from cache, recovering. > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 153333520 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_io_errors() nvme0n1p4: > IO error on reading from cache, recovering. > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 142766872 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_io_errors() nvme0n1p4: > IO error on reading from cache, recovering. > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 142766888 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_cache_set_error() error on > db563a68-d350-4eaf-978b-eee7095543c5: nvme0n1p4: too many IO errors > reading from cache#012, disabling caching > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 142766912 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 1, rd 0, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: blk_update_request: I/O error, dev > nvme0n1, sector 142766936 op 0x0:(READ) flags 0x80700 phys_seg 1 prio > class 0 > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache1 errs: wr 1, rd 0, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 2, rd 0, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache1 errs: wr 2, rd 0, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 3, rd 0, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: bcache: conditional_stop_bcache_device() > stop_when_cache_set_failed of bcache1 is "auto" and cache is dirty, stop > it to avoid potential data corruption. > Nov 11 00:24:58 tiare kernel: bcache: conditional_stop_bcache_device() > stop_when_cache_set_failed of bcache0 is "auto" and cache is dirty, stop > it to avoid potential data corruption. > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 3, rd 1, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 3, rd 2, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 3, rd 3, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 3, rd 4, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: BTRFS error (device bcache0): bdev > /dev/bcache0 errs: wr 3, rd 5, flush 0, corrupt 0, gen 0 > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: bcache: bch_count_backing_io_errors() sdc: > Read-ahead I/O failed on backing device, ignore > Nov 11 00:24:58 tiare kernel: nvme nvme0: 8/0/0 default/read/poll queues > Thanks, Pavel Goran
