Hey.
On Fri, 2018-08-31 at 10:33 +0800, Su Yue wrote: > Can you please fetch btrfs-progs from my repo and run lowmem check > in readonly? > Repo: https://github.com/Damenly/btrfs-progs/tree/lowmem_debug > It's based on v4.17.1 plus additonal output for debug only. I've adapted your patch to 4.17 from Debian (i.e. not the 4.17.1). First I ran it again with the pristine 4.17 from Debian: # btrfs check --mode=lowmem /dev/mapper/system ; echo $? Checking filesystem on /dev/mapper/system UUID: 6050ca10-e778-4d08-80e7-6d27b9c89b3c checking extents checking free space cache checking fs roots ERROR: errors found in fs roots found 435924422656 bytes used, error(s) found total csum bytes: 423418948 total tree bytes: 2218328064 total fs tree bytes: 1557168128 total extent tree bytes: 125894656 btree space waste bytes: 429599230 file data blocks allocated: 5193373646848 referenced 555255164928 [ 1248.687628] ------------[ cut here ]------------ [ 1248.688352] generic_make_request: Trying to write to read-only block-device dm-0 (partno 0) [ 1248.689127] WARNING: CPU: 3 PID: 933 at /build/linux-LgHyGB/linux-4.17.17/block/blk-core.c:2180 generic_make_request_checks+0x43d/0x610 [ 1248.689909] Modules linked in: dm_crypt algif_skcipher af_alg dm_mod snd_hda_codec_hdmi snd_hda_codec_realtek intel_rapl snd_hda_codec_generic x86_pkg_temp_thermal intel_powerclamp i915 iwlwifi btusb coretemp btrtl btbcm uvcvideo kvm_intel snd_hda_intel btintel videobuf2_vmalloc bluetooth snd_hda_codec kvm videobuf2_memops videobuf2_v4l2 videobuf2_common cfg80211 snd_hda_core irqbypass videodev jitterentropy_rng drm_kms_helper crct10dif_pclmul snd_hwdep crc32_pclmul drbg ghash_clmulni_intel intel_cstate snd_pcm ansi_cprng ppdev intel_uncore drm media ecdh_generic iTCO_wdt snd_timer iTCO_vendor_support rtsx_pci_ms crc16 snd intel_rapl_perf memstick joydev mei_me rfkill evdev soundcore sg parport_pc pcspkr serio_raw fujitsu_laptop mei i2c_algo_bit parport shpchp sparse_keymap pcc_cpufreq lpc_ich button [ 1248.693639] video battery ac ip_tables x_tables autofs4 btrfs zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod uas usb_storage crc32c_intel rtsx_pci_sdmmc mmc_core ahci xhci_pci libahci aesni_intel ehci_pci aes_x86_64 libata crypto_simd xhci_hcd ehci_hcd cryptd glue_helper psmouse i2c_i801 scsi_mod rtsx_pci e1000e usbcore usb_common [ 1248.696956] CPU: 3 PID: 933 Comm: btrfs Not tainted 4.17.0-3-amd64 #1 Debian 4.17.17-1 [ 1248.698118] Hardware name: FUJITSU LIFEBOOK E782/FJNB253, BIOS Version 2.11 07/15/2014 [ 1248.699299] RIP: 0010:generic_make_request_checks+0x43d/0x610 [ 1248.700495] RSP: 0018:ffffac89827c7d88 EFLAGS: 00010286 [ 1248.701702] RAX: 0000000000000000 RBX: ffff98f4848a9200 RCX: 0000000000000006 [ 1248.702930] RDX: 0000000000000007 RSI: 0000000000000082 RDI: ffff98f49e2d6730 [ 1248.704170] RBP: ffff98f484f6d460 R08: 000000000000033e R09: 0000000000aaaaaa [ 1248.705422] R10: ffffac89827c7e60 R11: 00000000ffffffff R12: 0000000000000000 [ 1248.706675] R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 [ 1248.707928] FS: 00007f92842018c0(0000) GS:ffff98f49e2c0000(0000) knlGS:0000000000000000 [ 1248.709190] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1248.710448] CR2: 000055fc6fe1a5b0 CR3: 0000000407f62001 CR4: 00000000001606e0 [ 1248.711707] Call Trace: [ 1248.712960] ? do_writepages+0x4b/0xe0 [ 1248.714201] ? blkdev_readpages+0x20/0x20 [ 1248.715441] ? do_writepages+0x4b/0xe0 [ 1248.716684] generic_make_request+0x64/0x400 [ 1248.717935] ? finish_wait+0x80/0x80 [ 1248.719181] ? mempool_alloc+0x67/0x1a0 [ 1248.720425] ? submit_bio+0x6c/0x140 [ 1248.721663] submit_bio+0x6c/0x140 [ 1248.722902] submit_bio_wait+0x53/0x80 [ 1248.724139] blkdev_issue_flush+0x7c/0xb0 [ 1248.725377] blkdev_fsync+0x2f/0x40 [ 1248.726612] do_fsync+0x38/0x60 [ 1248.727849] __x64_sys_fsync+0x10/0x20 [ 1248.729086] do_syscall_64+0x55/0x110 [ 1248.730323] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1248.731565] RIP: 0033:0x7f928354d161 [ 1248.732805] RSP: 002b:00007ffd35e3f5d8 EFLAGS: 00000246 ORIG_RAX: 000000000000004a [ 1248.734067] RAX: ffffffffffffffda RBX: 000055fc09c0c260 RCX: 00007f928354d161 [ 1248.735342] RDX: 000055fc09c13e28 RSI: 000055fc0899f820 RDI: 0000000000000004 [ 1248.736614] RBP: 000055fc09c0c2d0 R08: 0000000000000005 R09: 000055fc09c0da70 [ 1248.738001] R10: 000000000000009e R11: 0000000000000246 R12: 0000000000000000 [ 1248.739272] R13: 000055fc0899d213 R14: 000055fc09c0c290 R15: 0000000000000001 [ 1248.740542] Code: 24 54 03 00 00 48 8d 74 24 08 48 89 df c6 05 3e 03 d9 00 01 e8 d5 63 01 00 44 89 e2 48 89 c6 48 c7 c7 80 e1 e6 ad e8 a3 4e d1 ff <0f> 0b 4c 8b 63 08 e9 7b fc ff ff 80 3d 15 03 d9 00 00 0f 85 94 [ 1248.741909] ---[ end trace c2f580dbd579028c ]--- 1 Not really sure why btrfs-check apparently tries to write to the device (I've had set it blockdev --setro). And with your patch: # btrfs check --mode=lowmem /dev/mapper/system ; echo $? checking extents checking free space cache checking fs roots ERROR: errors found in fs roots Checking filesystem on /dev/mapper/system UUID: 6050ca10-e778-4d08-80e7-6d27b9c89b3c DEBUG: error before walking while checking fs root 3 ret -694376768 DEBUG: normal error in walking while checking node 125988438016 fs root 257 ret 524296 DEBUG: error in checking fs root 257 ret 524296 DEBUG: normal error in walking while checking node 230148259840 fs root 743 ret 524296 DEBUG: error in checking fs root 743 ret 524296 DEBUG: error in checking fs roots ret: found 435924422656 bytes used, error(s) found total csum bytes: 423418948 total tree bytes: 2218328064 total fs tree bytes: 1557168128 total extent tree bytes: 125894656 btree space waste bytes: 429599230 file data blocks allocated: 5193373646848 referenced 555255164928 1 Interestingly it doesn't try to write again (or the kernel doesn't just print another call trace this time). Cheers, Chris.
