[  +0,000008] INFO: task btrfs-transacti:949 blocked for more than 120 seconds.
[  +0,000032]       Not tainted 5.5.0-0.bpo.2-amd64 #1 Debian 5.5.17-1~bpo10+1
[  +0,000033] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  +0,000035] btrfs-transacti D    0   949      2 0x80004000
[  +0,000002] Call Trace:
[  +0,000003]  ? __schedule+0x2db/0x700
[  +0,000002]  schedule+0x40/0xb0
[  +0,000002]  io_schedule+0x12/0x40
[  +0,000004]  wait_on_page_bit+0x15c/0x230
[  +0,000002]  ? file_fdatawait_range+0x20/0x20
[  +0,000002]  __filemap_fdatawait_range+0x89/0xf0
[  +0,000027]  ? __clear_extent_bit+0x2bd/0x440 [btrfs]
[  +0,000002]  filemap_fdatawait_range+0xe/0x20
[  +0,000022]  __btrfs_wait_marked_extents.isra.20+0xc2/0x100 [btrfs]
[  +0,000022]  btrfs_write_and_wait_transaction.isra.24+0x67/0xd0 [btrfs]
[  +0,000022]  btrfs_commit_transaction+0x754/0xa40 [btrfs]
[  +0,000022]  ? start_transaction+0xbc/0x4d0 [btrfs]
[  +0,000022]  transaction_kthread+0x144/0x170 [btrfs]
[  +0,000021]  ? btrfs_cleanup_transaction+0x5e0/0x5e0 [btrfs]
[  +0,000002]  kthread+0x112/0x130
[  +0,000001]  ? kthread_park+0x80/0x80
[  +0,000002]  ret_from_fork+0x22/0x40