On 09/04/2018 04:24 AM, Christoph Anton Mitterer wrote:
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).
Agreed with Qu, btrfs-check shall not try to do any write.
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
I found the errors should blame to something about inode_extref check
in lowmem mode.
I have writeen three patches to detect and report errors about
inode_extref. For your convenience, it's based on v4.17:
https://github.com/Damenly/btrfs-progs/tree/ext_ref_v4.17
This repo should report more errors. Because one of those is just
Whac-A-Mole, I will make it better and send them later to ML.
Thanks,
Su
Interestingly it doesn't try to write again (or the kernel doesn't just
print another call trace this time).
Cheers,
Chris.
