fs/btrfs/ctree.h:1559 warnings

fs/btrfs/ctree.h:1559 warnings

[Paul Richards]

Hi,
I recently upgraded from Linux 4.4.0 to 4.13.0 (Ubuntu 16.04 stock to
hwe kernel).

Since then, I've noticed lots of btrfs warnings in dmesg (example at
the end).  I believe these warnings to be benign, and they relate to
my partition not being a multiple of 4KiB in size (I confirmed that
alignment is okay in this instance).

I would like to confirm a couple of things:

1. Is this warning definitely safe to ignore?

2. If this warning is a false alarm, has it been removed in more
recent kernel versions (after 4.13)?  I'd like to know if the warning
will go away when I upgrade the kernel further, or if I'll have to
recreate my partitions in order to resolve these warnings (which clog
dmesg).


Thanks.

Example:

[101320.529729] ------------[ cut here ]------------

[101320.529761] WARNING: CPU: 1 PID: 5027 at
/build/linux-hwe-v6kHHF/linux-hwe-4.13.0/fs/btrfs/ctree.h:1559
btrfs_update_device+0x1b4/0x1c0 [btrfs]

[101320.529762] Modules linked in: binfmt_misc dm_crypt crypto_simd
glue_helper aes_x86_64 algif_skcipher af_alg gpio_ich intel_rapl
x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass
intel_cstate intel_rapl_perf ipmi_ssif serio_raw ipmi_si hpilo
acpi_power_meter ipmi_devintf ipmi_msghandler mac_hid lpc_ich shpchp
ie31200_edac ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp
libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10
raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor
raid6_pq libcrc32c raid1 raid0 multipath linear mgag200 i2c_algo_bit
ttm crct10dif_pclmul uas drm_kms_helper tg3 syscopyarea sysfillrect
sysimgblt fb_sys_fops crc32_pclmul ptp ghash_clmulni_intel cryptd
psmouse ahci libahci usb_storage drm pps_core

[101320.529803] CPU: 1 PID: 5027 Comm: kworker/u128:8 Tainted: G
 W       4.13.0-39-generic #44~16.04.1-Ubuntu

[101320.529804] Hardware name: HP ProLiant MicroServer Gen8, BIOS J06 06/06/2014

[101320.529809] Workqueue: writeback wb_workfn (flush-btrfs-2)

[101320.529811] task: ffff9602b332d900 task.stack: ffffa4ca02e08000

[101320.529829] RIP: 0010:btrfs_update_device+0x1b4/0x1c0 [btrfs]

[101320.529830] RSP: 0018:ffffa4ca02e0b498 EFLAGS: 00010206

[101320.529831] RAX: 0000000000000fff RBX: 0000000000000000 RCX:
0000074702251e00

[101320.529832] RDX: 0000000000000004 RSI: 0000000000003f5c RDI:
ffff9602947aedf0

[101320.529833] RBP: ffffa4ca02e0b4e0 R08: 0000000000003f60 R09:
ffffa4ca02e0b450

[101320.529834] R10: 0000000000001000 R11: 0000000000000003 R12:
ffff9602b3a391c0

[101320.529835] R13: ffff9602f1bbe400 R14: 0000000000003f3c R15:
ffff9602947aedf0

[101320.529837] FS:  0000000000000000(0000) GS:ffff9602fa440000(0000)
knlGS:0000000000000000

[101320.529838] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033

[101320.529839] CR2: 00007feb823bb000 CR3: 000000002740a005 CR4:
00000000001606e0

[101320.529840] Call Trace:

[101320.529860]  btrfs_finish_chunk_alloc+0x134/0x510 [btrfs]

[101320.529877]  ? free_extent_buffer+0x4b/0xa0 [btrfs]

[101320.529891]  ? btrfs_insert_item+0x80/0xf0 [btrfs]

[101320.529906]  btrfs_create_pending_block_groups+0x135/0x250 [btrfs]

[101320.529919]  ? btrfs_create_pending_block_groups+0x135/0x250 [btrfs]

[101320.529936]  __btrfs_end_transaction+0x8e/0x2e0 [btrfs]

[101320.529951]  btrfs_end_transaction+0x10/0x20 [btrfs]

[101320.529965]  find_free_extent+0xd12/0xfe0 [btrfs]

[101320.529981]  ? btrfs_defrag_leaves+0x360/0x360 [btrfs]

[101320.529996]  btrfs_reserve_extent+0x9b/0x1f0 [btrfs]

[101320.530011]  cow_file_range.isra.62+0x15b/0x430 [btrfs]

[101320.530026]  run_delalloc_range+0x2ba/0x3a0 [btrfs]

[101320.530042]  ? find_lock_delalloc_range.constprop.55+0x1d3/0x200 [btrfs]

[101320.530058]  writepage_delalloc.isra.45+0x10d/0x170 [btrfs]

[101320.530073]  __extent_writepage+0xd9/0x300 [btrfs]

[101320.530088]  extent_write_cache_pages.constprop.52+0x2c5/0x400 [btrfs]

[101320.530104]  extent_writepages+0x5c/0x90 [btrfs]

[101320.530119]  ? btrfs_releasepage+0x20/0x20 [btrfs]

[101320.530133]  btrfs_writepages+0x28/0x30 [btrfs]

[101320.530136]  do_writepages+0x1f/0x70

[101320.530138]  __writeback_single_inode+0x45/0x330

[101320.530141]  ? fprop_reflect_period_percpu.isra.5+0x8e/0xc0

[101320.530143]  writeback_sb_inodes+0x26a/0x600

[101320.530146]  __writeback_inodes_wb+0x92/0xc0

[101320.530148]  wb_writeback+0x274/0x330

[101320.530151]  wb_workfn+0x18a/0x3b0

[101320.530152]  ? wb_workfn+0x18a/0x3b0

[101320.530156]  process_one_work+0x15b/0x410

[101320.530158]  worker_thread+0x4b/0x460

[101320.530161]  kthread+0x10c/0x140

[101320.530163]  ? process_one_work+0x410/0x410

[101320.530164]  ? kthread_create_on_node+0x70/0x70

[101320.530166]  ret_from_fork+0x35/0x40

[101320.530168] Code: 00 4c 89 ff 45 31 c0 ba 10 00 00 00 4c 89 f6 e8
73 23 ff ff 4c 89 ff e8 7b f5 fc ff e9 d9 fe ff ff b8 f4 ff ff ff e9
d9 fe ff ff <0f> ff eb b8 e8 53 08 01 cb 0f 1f 00 0f 1f 44 00 00 55 48
89 e5

[101320.530199] ---[ end trace 7a108943044dc9ba ]---

Re: fs/btrfs/ctree.h:1559 warnings

[Paul Richards]

On 28 April 2018 at 20:39, Patrik Lundquist <patrik.lundquist@gmail.com> wrote:
> On 28 April 2018 at 20:54, Paul Richards <paul.richards@gmail.com> wrote:
>>
>> Hi,
>> I recently upgraded from Linux 4.4.0 to 4.13.0 (Ubuntu 16.04 stock to
>> hwe kernel).
>>
>> Since then, I've noticed lots of btrfs warnings in dmesg (example at
>> the end).  I believe these warnings to be benign, and they relate to
>> my partition not being a multiple of 4KiB in size (I confirmed that
>> alignment is okay in this instance).
>
>
> Run btrfs rescue fix-device-size <device>.
>


Excellent, that looks like exactly what I need.  It's a shame my
google-fu didn't uncover it before I posted.

However, the "fix-device-size" sub-command is not available in
btrfs-tools (v4.4) from Ubuntu 16.04.  I guess my original question
still stands.  Is this warning safe for me to ignore?


I will likely upgrade to Ubuntu 18.04 in a few months at which point
I'll get a newer btrfs-tools, but until then can I safely ignore this
warning?

Re: fs/btrfs/ctree.h:1559 warnings

[Qu Wenruo]

[-- Attachment #1.1: Type: text/plain, Size: 1542 bytes --]



On 2018年04月29日 04:16, Paul Richards wrote:
> On 28 April 2018 at 20:39, Patrik Lundquist <patrik.lundquist@gmail.com> wrote:
>> On 28 April 2018 at 20:54, Paul Richards <paul.richards@gmail.com> wrote:
>>>
>>> Hi,
>>> I recently upgraded from Linux 4.4.0 to 4.13.0 (Ubuntu 16.04 stock to
>>> hwe kernel).
>>>
>>> Since then, I've noticed lots of btrfs warnings in dmesg (example at
>>> the end).  I believe these warnings to be benign, and they relate to
>>> my partition not being a multiple of 4KiB in size (I confirmed that
>>> alignment is okay in this instance).
>>
>>
>> Run btrfs rescue fix-device-size <device>.
>>
> 
> 
> Excellent, that looks like exactly what I need.  It's a shame my
> google-fu didn't uncover it before I posted.
> 
> However, the "fix-device-size" sub-command is not available in
> btrfs-tools (v4.4) from Ubuntu 16.04.  I guess my original question
> still stands.  Is this warning safe for me to ignore?

Safe to ignore.

And there is another way to solve it.

Shrink your fs by 4K, and newer kernel will do the round down for you
and result new device size to be aligned.

Thanks,
Qu

> 
> 
> I will likely upgrade to Ubuntu 18.04 in a few months at which point
> I'll get a newer btrfs-tools, but until then can I safely ignore this
> warning?
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 


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Re: fs/btrfs/ctree.h:1559 warnings

[Paul Richards]

On 29 April 2018 at 02:50, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>
>
> On 2018年04月29日 04:16, Paul Richards wrote:
>> On 28 April 2018 at 20:39, Patrik Lundquist <patrik.lundquist@gmail.com> wrote:
>>> On 28 April 2018 at 20:54, Paul Richards <paul.richards@gmail.com> wrote:
>>>>
>>>> Hi,
>>>> I recently upgraded from Linux 4.4.0 to 4.13.0 (Ubuntu 16.04 stock to
>>>> hwe kernel).
>>>>
>>>> Since then, I've noticed lots of btrfs warnings in dmesg (example at
>>>> the end).  I believe these warnings to be benign, and they relate to
>>>> my partition not being a multiple of 4KiB in size (I confirmed that
>>>> alignment is okay in this instance).
>>>
>>>
>>> Run btrfs rescue fix-device-size <device>.
>>>
>>
>>
>> Excellent, that looks like exactly what I need.  It's a shame my
>> google-fu didn't uncover it before I posted.
>>
>> However, the "fix-device-size" sub-command is not available in
>> btrfs-tools (v4.4) from Ubuntu 16.04.  I guess my original question
>> still stands.  Is this warning safe for me to ignore?
>
> Safe to ignore.
>
> And there is another way to solve it.
>
> Shrink your fs by 4K, and newer kernel will do the round down for you
> and result new device size to be aligned.
>
> Thanks,
> Qu
>


Thanks - this fixed the issue for me (modulo my problem below..).  I
thought I should follow up with exactly what I did for anyone else
looking to fix this.

I used this command to identify which devices were not exact multiples
of 4KiB in size:

% btrfs fi show --raw /storage
Label: none  uuid: c4b33374-9006-47d7-b6f9-2136dc988f9a
Total devices 3 FS bytes used 7027891666944
devid    1 size 8001560055808 used 4691211583488 path /dev/mapper/storage1
devid    3 size 8001560059392 used 4691211583488 path /dev/mapper/storage3
devid    4 size 8001560059392 used 4690104287232 path /dev/mapper/storage4

I used a calculator to determine that devids 3 and 4 were the
offenders (they don't divide by 4006 nicely).


I then ran:
% btrfs fi resize 3:-1K /storage
% btrfs fi resize 4:-1K /storage

Which has resulted in this:
% btrfs fi show --raw /storage
Label: none  uuid: c4b33374-9006-47d7-b6f9-2136dc988f9a
Total devices 3 FS bytes used 7027891666944
devid    1 size 8001560055808 used 4691211583488 path /dev/mapper/storage1
devid    3 size 8001560055808 used 4691211583488 path /dev/mapper/storage3
devid    4 size 8001560055808 used 4690104287232 path /dev/mapper/storage4

PERFECT! :)


The issue I have now is that the filesystem cannot be unmounted.
"umount" reports "target is busy", but I cannot find anything relevant
with "lsof" or "fuser" (this is a very quiet home NAS).  Is this
something related to the resize?



For what it's worth, here are the sizes of the underlying devices
(output somewhat redacted):

% lsblk -b
NAME         MAJ:MIN RM          SIZE RO TYPE  MOUNTPOINT
storage3 253:2    0 8001560059392  0 crypt
storage4 253:1    0 8001560059392  0 crypt
storage1 253:0    0 8001560059392  0 crypt /storage/.snapshots

It looks like all the devices are an odd size.  One of these disks was
added after the others, presumably with a newer kernel that rounded
the btrfs dev size downwards.

Re: fs/btrfs/ctree.h:1559 warnings

[Paul Richards]

On 2 May 2018 at 20:43, Paul Richards <paul.richards@gmail.com> wrote:
> The issue I have now is that the filesystem cannot be unmounted.
> "umount" reports "target is busy", but I cannot find anything relevant
> with "lsof" or "fuser" (this is a very quiet home NAS).  Is this
> something related to the resize?
>

Oh please ignore me.  I forgot to unmount "/storage/.snapshots" before
"/storage".

Everything looks fine.