Re: Simple quota unsafe? RIP: 0010:__btrfs_free_extent.isra.0+0xc41/0x1020 [btrfs] / do_free_extent_accounting:2999: errno=-2 No such entry

[Marc MERLIN <marc_btrfs@merlins.org>]

No help needed, just showing it happened overnight with balance and squota in 6.19
on my laptop. It looks like squota and balance are simply not compatible until the
fix for squota, lands.
Now that I know more, I rescued the FS and removed squota on my own and it's good again.

It looks pretty clear that btrfs balance seems to trigger the bug in
squota:
[37930.185472] BTRFS info (device dm-3): balance: start -dusage=20
[37930.187010] BTRFS info (device dm-3): relocating block group 4502498312192 flags data
[37930.417388] BTRFS info (device dm-3): found 83 extents, stage: move data extents
[37930.896615] BTRFS info (device dm-3): found 83 extents, stage: update data pointers
[37931.311770] BTRFS info (device dm-3): relocating block group 4501424570368 flags data
[37931.355759] BTRFS info (device dm-3): found 11 extents, stage: move data extents
[37931.501741] BTRFS info (device dm-3): found 11 extents, stage: update data pointers
[37931.507435] BTRFS: Transaction aborted (error -2)
[37931.508762] BTRFS: error (device dm-3 state A) in do_free_extent_accounting:3002: errno=-2 No such entry
[37931.508766] BTRFS info (device dm-3 state EA): forced readonly
[37931.508769] BTRFS error (device dm-3 state EA): failed to run delayed ref for logical 907535646720 num_bytes 16384 type 182 action 2 ref_mod 1: -2
[37931.508773] BTRFS: error (device dm-3 state EA) in btrfs_run_delayed_refs:2166: errno=-2 No such entry
[37931.508798] BTRFS info (device dm-3 state EA): balance: ended with status: -2

[37931.507428] ------------[ cut here ]------------
[37931.507435] BTRFS: Transaction aborted (error -2)
[37931.507438] WARNING: fs/btrfs/extent-tree.c:3002 at __btrfs_free_extent.isra.0+0xdf6/0xfe0 [btrfs], CPU#0: btrfs/153883
[37931.507519] Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfs netfs sd_mod sg uas usb_storage uinput nf_conntrack_netlink xfrm_user xfrm_algo xt_addrtype br_netfilter bridge stp llc xt_tcpudp xt_conntrack ccm rfcomm snd_seq_dummy snd_hrtimer overlay ipt_REJECT nf_reject_ipv4 xt_MASQUERADE xt_LOG nf_log_syslog nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 qrtr nf_tables cmac algif_hash algif_skcipher af_alg bnep binfmt_misc uvcvideo btusb videobuf2_vmalloc btmtk uvc videobuf2_memops btrtl videobuf2_v4l2 btbcm btintel videodev videobuf2_common bluetooth mc ftdi_sio ecdh_generic usbserial nls_ascii nls_cp437 vfat fat ext4 crc16 mbcache squashfs jbd2 loop intel_uncore_frequency intel_uncore_frequency_common x86_pkg_temp_thermal iwlmvm intel_powerclamp snd_hda_codec_intelhdmi kvm_intel snd_hda_codec_alc269 snd_hda_scodec_component snd_hda_codec_realtek_lib mac80211 snd_hda_codec_generic kvm snd_soc_dmic rtsx_pci_sdmmc mmc_core libarc4 snd_sof_pci_intel_tgl irqbypass mei_hdcp mei_pxp
[37931.507593]  intel_rapl_msr snd_sof_pci_intel_cnl rapl intel_cstate snd_sof_intel_hda_generic soundwire_intel snd_sof_pci snd_sof_xtensa_dsp snd_sof_intel_hda_sdw_bpt processor_thermal_device_pci_legacy iwlwifi intel_uncore think_lmi snd_sof_intel_hda_common iTCO_wdt snd_soc_sdw_utils processor_thermal_device processor_thermal_wt_hint intel_pmc_bxt snd_soc_hdac_hda firmware_attributes_class snd_hda_intel platform_temperature_control wmi_bmof iTCO_vendor_support snd_sof_intel_hda_mlink processor_thermal_soc_slider snd_soc_avs cfg80211 processor_thermal_rfim ee1004 snd_sof_intel_hda processor_thermal_rapl watchdog pcspkr snd_soc_hda_codec rtsx_pci snd_hda_codec_hdmi intel_rapl_common ucsi_acpi processor_thermal_wt_req typec_ucsi mei_me soundwire_cadence processor_thermal_power_floor mei snd_hda_ext_core typec soundwire_generic_allocation processor_thermal_mbox crc8 roles soundwire_bus thinkpad_acpi intel_soc_dts_iosf snd_sof_probes nvram platform_profile int3403_thermal snd_sof rfkill int340x_thermal_zone ac
[37931.507644]  intel_pmc_core snd_sof_utils pmt_telemetry snd_intel_dspcfg pmt_discovery pmt_class snd_intel_sdw_acpi int3400_thermal joydev intel_hid intel_pmc_ssram_telemetry sparse_keymap snd_soc_skl_hda_dsp acpi_thermal_rel snd_soc_intel_sof_board_helpers acpi_pad button acpi_tad snd_soc_acpi_intel_match evdev snd_soc_acpi_intel_sdca_quirks snd_soc_acpi serio_raw snd_soc_sdca snd_soc_core snd_compress snd_pcm_dmaengine snd_soc_intel_hda_dsp_common snd_hda_codec snd_hda_core snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_midi snd_seq_midi_event snd_seq snd_timer snd_rawmidi snd_seq_device snd_ctl_led snd nfsd soundcore ac97_bus coretemp auth_rpcgss msr ecryptfs nfs_acl lockd grace efi_pstore sunrpc nfnetlink ip_tables x_tables autofs4 crc32c_cryptoapi essiv authenc btrfs blake2b libblake2b dm_crypt dm_mod efivarfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 md_mod sata_sil24 libata scsi_mod scsi_common e1000e r8169 realtek mii xe intel_vsec drm_gpuvm
[37931.507715]  configfs drm_gpusvm_helper gpu_sched drm_ttm_helper drm_exec drm_suballoc_helper hid_generic usbhid hid i915 drm_buddy ttm i2c_algo_bit drm_display_helper xhci_pci cec nvme xhci_hcd rc_core nvme_core drm_client_lib usbcore drm_kms_helper nvme_keyring video i2c_i801 ghash_clmulni_intel psmouse i2c_smbus nvme_auth igc hkdf drm thunderbolt usb_common battery wmi aesni_intel
[37931.507761] CPU: 0 UID: 0 PID: 153883 Comm: btrfs Tainted: G S   U              6.19.11+deb14-amd64 #1 PREEMPT(lazy)  Debian 6.19.11-1 
[37931.507765] Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
[37931.507767] Hardware name: LENOVO 20YU002JUS/20YU002JUS, BIOS N37ET61W (1.97 ) 09/17/2025
[37931.507769] RIP: 0010:__btrfs_free_extent.isra.0+0xdfa/0xfe0 [btrfs]
[37931.507830] Code: 48 c7 c6 50 e1 a0 c1 48 8b 78 60 e8 30 80 0f 00 e8 4b e9 62 d9 44 88 6c 24 2f e9 98 aa 0e 00 48 8d 3d 6a 49 f4 ff 8b 74 24 14 <67> 48 0f b9 3a e9 ef fd ff ff 48 8d 3d 65 49 f4 ff 8b 74 24 14 67
[37931.507833] RSP: 0018:ffffcc4b75297800 EFLAGS: 00010206
[37931.507836] RAX: 000000000000001c RBX: 000000d34d570000 RCX: ffff891a04502000
[37931.507838] RDX: 0000000000000000 RSI: 00000000fffffffe RDI: ffffffffc176e990
[37931.507840] RBP: 0000000000000000 R08: ffff89275fe8e2d0 R09: ffff89275fe8e2d0
[37931.507842] R10: ffff891a04502000 R11: 0000000000000011 R12: 0000000000004000
[37931.507843] R13: 0000000000000000 R14: ffff892b31377380 R15: 0000000000000010
[37931.507845] FS:  00007fa538c1d3c0(0000) GS:ffff893951da7000(0000) knlGS:0000000000000000
[37931.507847] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[37931.507849] CR2: 00003c840b875500 CR3: 00000010f962b005 CR4: 0000000000f70ef0
[37931.507851] PKRU: 55555554
[37931.507853] Call Trace:
[37931.507856]  <TASK>
[37931.507862]  __btrfs_run_delayed_refs+0x2e3/0xfb0 [btrfs]
[37931.507915]  ? need_preemptive_reclaim+0x36/0x190 [btrfs]
[37931.507976]  ? reserve_bytes+0x177/0x4a0 [btrfs]
[37931.508032]  btrfs_run_delayed_refs+0x3b/0x120 [btrfs]
[37931.508085]  btrfs_commit_transaction+0x6a/0xd50 [btrfs]
[37931.508142]  ? btrfs_init_metadata_block_rsv+0x28/0x40 [btrfs]
[37931.508200]  ? start_transaction+0x228/0x840 [btrfs]
[37931.508256]  prepare_to_relocate+0x135/0x1d0 [btrfs]
[37931.508323]  relocate_block_group+0x6b/0x530 [btrfs]
[37931.508382]  btrfs_relocate_block_group+0x26e/0x3d0 [btrfs]
[37931.508439]  btrfs_relocate_chunk+0x44/0x170 [btrfs]
[37931.508504]  btrfs_balance+0xa5b/0x1640 [btrfs]
[37931.508568]  btrfs_ioctl+0x28ac/0x2dd0 [btrfs]
[37931.508635]  ? kmem_cache_free+0x508/0x550
[37931.508640]  ? dput.part.0+0x27/0x110
[37931.508643]  ? __x64_sys_close+0x3d/0x80
[37931.508647]  __x64_sys_ioctl+0x97/0xe0
[37931.508651]  do_syscall_64+0x81/0x5e0
[37931.508656]  ? syscall_exit_work+0x143/0x1b0
[37931.508665]  ? do_syscall_64+0xbe/0x5e0
[37931.508671]  ? syscall_exit_work+0x143/0x1b0
[37931.508674]  ? do_syscall_64+0xbe/0x5e0
[37931.508676]  ? kernfs_fop_llseek+0x78/0xc0
[37931.508682]  ? syscall_exit_work+0x143/0x1b0
[37931.508685]  ? do_syscall_64+0xbe/0x5e0
[37931.508687]  ? clear_bhb_loop+0x50/0xa0
[37931.508690]  ? clear_bhb_loop+0x50/0xa0
[37931.508692]  ? clear_bhb_loop+0x50/0xa0
[37931.508695]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[37931.508697] RIP: 0033:0x7fa538d3ad3b
[37931.508741] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
[37931.508744] RSP: 002b:00007fff72a15140 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[37931.508747] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa538d3ad3b
[37931.508749] RDX: 00007fff72a15228 RSI: 00000000c4009420 RDI: 0000000000000003
[37931.508750] RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
[37931.508752] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff72a15228
[37931.508753] R13: 00007fff72a15bd8 R14: 00007fff72a17da5 R15: 0000000000000001
[37931.508756]  </TASK>
[37931.508758] ---[ end trace 0000000000000000 ]---
[37931.508762] BTRFS: error (device dm-3 state A) in do_free_extent_accounting:3002: errno=-2 No such entry
[37931.508766] BTRFS info (device dm-3 state EA): forced readonly
[37931.508769] BTRFS error (device dm-3 state EA): failed to run delayed ref for logical 907535646720 num_bytes 16384 type 182 action 2 ref_mod 1: -2
[37931.508773] BTRFS: error (device dm-3 state EA) in btrfs_run_delayed_refs:2166: errno=-2 No such entry

sauron:/boot# mount /dev/mapper/pool4 /mnt/btrfs_pool4
[65964.162801] BTRFS error (device dm-3 state EMA): remounting read-write after error is not allowed

For google and people who find that thread, the quicker recovery is:
sauron:/mnt/btrfs_pool3# btrfs rescue clear-ino-cache  /dev/mapper/pool4
(...)
Successfully cleaned up ino cache for root id: 108518
Successfully cleared ino cache
sauron:/mnt/btrfs_pool3# mount -o rw,clear_cache,enospc_debug,skip_balance LABEL=btrfs_pool4 /mnt/btrfs_pool4
sauron:/mnt/btrfs_pool3# btrfs quota disable /mnt/btrfs_pool4

sauron:/mnt/btrfs_pool3# mount /dev/mapper/pool4 /mnt/btrfs_pool4
sauron:/mnt/btrfs_pool3# cd /mnt/btrfs_pool4
sauron:/mnt/btrfs_pool4# btrfs balance start -dusage=20  `pwd`
Done, had to relocate 0 out of 2008 chunks
sauron:/mnt/btrfs_pool4# 

btrfs tune would have likely also worked to remove squota, but the trick
after that is mounting with skip_balance or otherwise, even after quota
removal, balance restarts right away and puts the FS read only again
if squota isn't disabled first.

Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
 
Home page: http://marc.merlins.org/                       | PGP 7F55D5F27AAF9D08