Re: Btrfs resize seems to deadlock

[Liu Bo <obuil.liubo@gmail.com>]

On Fri, Oct 19, 2018 at 7:09 PM Andrew Nelson <andrew.s.nelson@gmail.com> wrote:
>
> I am having an issue with btrfs resize in Fedora 28. I am attempting
> to enlarge my Btrfs partition. Every time I run "btrfs filesystem
> resize max $MOUNT", the command runs for a few minutes and then hangs
> forcing the system to be reset. I am not sure what the state of the
> filesystem really is at this point. Btrfs usage does report the
> correct size for after resizing. Details below:
>

Thanks for the report, the stack is helpful, but this needs a few
deeper debugging, may I ask you to post "btrfs inspect-internal
dump-tree -t 1 /dev/your_btrfs_disk"?

So I'd like to know what's the height of your tree "1" which refers to
root tree in btrfs.

thanks,
liubo

> $ sudo btrfs filesystem usage $MOUNT
> Overall:
>     Device size:                  90.96TiB
>     Device allocated:             72.62TiB
>     Device unallocated:           18.33TiB
>     Device missing:                  0.00B
>     Used:                         72.62TiB
>     Free (estimated):             18.34TiB      (min: 9.17TiB)
>     Data ratio:                       1.00
>     Metadata ratio:                   2.00
>     Global reserve:              512.00MiB      (used: 24.11MiB)
>
> Data,single: Size:72.46TiB, Used:72.45TiB
>     $MOUNT        72.46TiB
>
> Metadata,DUP: Size:86.00GiB, Used:84.96GiB
>     $MOUNT       172.00GiB
>
> System,DUP: Size:40.00MiB, Used:7.53MiB
>    $MOUNT        80.00MiB
>
> Unallocated:
>     $MOUNT        18.33TiB
>
> $ uname -a
> Linux localhost.localdomain 4.18.14-200.fc28.x86_64 #1 SMP Mon Oct 15
> 13:16:27 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
>
> btrfs-transacti D    0  2501      2 0x80000000
> Call Trace:
>  ? __schedule+0x253/0x860
>  schedule+0x28/0x80
>  btrfs_commit_transaction+0x7aa/0x8b0 [btrfs]
>  ? kmem_cache_alloc+0x166/0x1d0
>  ? join_transaction+0x22/0x3e0 [btrfs]
>  ? finish_wait+0x80/0x80
>  transaction_kthread+0x155/0x170 [btrfs]
>  ? btrfs_cleanup_transaction+0x550/0x550 [btrfs]
>  kthread+0x112/0x130
>  ? kthread_create_worker_on_cpu+0x70/0x70
>  ret_from_fork+0x35/0x40
> btrfs           D    0  2504   2502 0x00000002
> Call Trace:
>  ? __schedule+0x253/0x860
>  schedule+0x28/0x80
>  btrfs_tree_read_lock+0x8e/0x120 [btrfs]
>  ? finish_wait+0x80/0x80
>  btrfs_read_lock_root_node+0x2f/0x40 [btrfs]
>  btrfs_search_slot+0xf6/0x9f0 [btrfs]
>  ? evict_refill_and_join+0xd0/0xd0 [btrfs]
>  ? inode_insert5+0x119/0x190
>  btrfs_lookup_inode+0x3a/0xc0 [btrfs]
>  ? kmem_cache_alloc+0x166/0x1d0
>  btrfs_iget+0x113/0x690 [btrfs]
>  __lookup_free_space_inode+0xd8/0x150 [btrfs]
>  lookup_free_space_inode+0x5b/0xb0 [btrfs]
>  load_free_space_cache+0x7c/0x170 [btrfs]
>  ? cache_block_group+0x72/0x3b0 [btrfs]
>  cache_block_group+0x1b3/0x3b0 [btrfs]
>  ? finish_wait+0x80/0x80
>  find_free_extent+0x799/0x1010 [btrfs]
>  btrfs_reserve_extent+0x9b/0x180 [btrfs]
>  btrfs_alloc_tree_block+0x1b3/0x4f0 [btrfs]
>  __btrfs_cow_block+0x11d/0x500 [btrfs]
>  btrfs_cow_block+0xdc/0x180 [btrfs]
>  btrfs_search_slot+0x3bd/0x9f0 [btrfs]
>  btrfs_lookup_inode+0x3a/0xc0 [btrfs]
>  ? kmem_cache_alloc+0x166/0x1d0
>  btrfs_update_inode_item+0x46/0x100 [btrfs]
>  cache_save_setup+0xe4/0x3a0 [btrfs]
>  btrfs_start_dirty_block_groups+0x1be/0x480 [btrfs]
>  btrfs_commit_transaction+0xcb/0x8b0 [btrfs]
>  ? btrfs_release_path+0x13/0x80 [btrfs]
>  ? btrfs_update_device+0x8d/0x1c0 [btrfs]
>  btrfs_ioctl_resize.cold.46+0xf4/0xf9 [btrfs]
>  btrfs_ioctl+0xa25/0x2cf0 [btrfs]
>  ? tty_write+0x1fc/0x330
>  ? do_vfs_ioctl+0xa4/0x620
>  do_vfs_ioctl+0xa4/0x620
>  ksys_ioctl+0x60/0x90
>  ? ksys_write+0x4f/0xb0
>  __x64_sys_ioctl+0x16/0x20
>  do_syscall_64+0x5b/0x160
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x7fcdc0d78c57
> Code: Bad RIP value.
> RSP: 002b:00007ffdd1ee6cf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007ffdd1ee888a RCX: 00007fcdc0d78c57
> RDX: 00007ffdd1ee6da0 RSI: 0000000050009403 RDI: 0000000000000003
> RBP: 00007ffdd1ee6da0 R08: 0000000000000000 R09: 00007ffdd1ee67e0
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdd1ee888e
> R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
> kworker/u48:1   D    0  2505      2 0x80000000
> Workqueue: btrfs-freespace-write btrfs_freespace_write_helper [btrfs]
> Call Trace:
>  ? __schedule+0x253/0x860
>  schedule+0x28/0x80
>  btrfs_tree_lock+0x130/0x210 [btrfs]
>  ? finish_wait+0x80/0x80
>  btrfs_search_slot+0x775/0x9f0 [btrfs]
>  btrfs_mark_extent_written+0xb0/0xb20 [btrfs]
>  ? join_transaction+0x22/0x3e0 [btrfs]
>  btrfs_finish_ordered_io+0x2e0/0x7e0 [btrfs]
>  ? syscall_return_via_sysret+0x13/0x83
>  ? __switch_to_asm+0x34/0x70
>  normal_work_helper+0xd3/0x2f0 [btrfs]
>  process_one_work+0x1a1/0x350
>  worker_thread+0x30/0x380
>  ? pwq_unbound_release_workfn+0xd0/0xd0
>  kthread+0x112/0x130
>  ? kthread_create_worker_on_cpu+0x70/0x70
>  ret_from_fork+0x35/0x40