Hello.


I had a problem with the mounting of the BTRFS file system.

Test case description:

1. Operation: Creating btrfs: sudo mkfs.btrfs -O zoned -d single -m 
single -f /dev/sdb
Result: The file system was created successfully

2. Operation: Mount new btrfs: sudo mount /dev/sdb /mnt/sdb
Result: Mounted successfully

3. Operation: Filling a file system data system (copy using MC)
Result: Filling a file system data has passed successfully, the data has 
passed integrity control

4. Operation: Umount file system: sudo umount /mnt/sdb/
Result: Umounted successfully

5. Operation: Mount btrfs: sudo mount /dev/sdb /mnt/sdb
Result: Mounted successfully

6. Operation: rebooted the host with mounted file system BTRFS
Result: Reboot successfully

7. Operation: Checking the btrfs file system: sudo btrfs check /dev/sdb
Result: successfully, console output:
Opening filesystem to check...
Checking filesystem on /dev/sdb
UUID: 4312bf2a-376d-4a44-a69a-6bb112b124f6
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space cache
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
found 17978056441856 bytes used, no error found
total csum bytes: 17534343280
total tree bytes: 22888923136
total fs tree bytes: 2191491072
total extent tree bytes: 2166554624
btree space waste bytes: 990047274
file data blocks allocated: 17955167518720
  referenced 17955167518720

8. Operation: Attempt to mount 1: sudo mount /dev/sdb /mnt/sdb
Result: Mounted unsuccessful,
Console output: mount: /mnt/sdb: wrong fs type, bad option, bad 
superblock on /dev/sdb, missing codepage or helper program, or other error.

9. Operation: Attempt to mount 2: sudo mount -t btrfs /dev/sdb /mnt/sdb
Result: unsuccessful, no messages, the HDD activity LED is glow, the 
console frozen, ^C does not interrupt the mount operation, the sudo 
reboot is not performed, the restart of Alt+PRTSCR+B is performed.

Version of the kernel:
$ uname -a
Linux x79zd3 5.14.0-051400rc2-generic #202107182230 SMP Sun Jul 18 
22:34:12 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

$ btrfs --version
btrfs-progs v5.13
from https://github.com/kdave/btrfs-progs

$ btrfs fi show
nothing output

$ btrfs fi df /mnt/sdb
ERROR: not a btrfs filesystem: /mnt/sdb

Device:
$ sudo smartctl -i /dev/sdb
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.14.0-051400rc2-generic] 
(local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     ST18000NM009J-2UW101
Serial Number:    ZL2BH53L
LU WWN Device Id: 5 000c50 0c812bf64
Firmware Version: SE01
User Capacity:    18 000 207 937 536 bytes [18,0 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ACS-4 (minor revision not indicated)
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Fri Jul 30 14:47:33 2021 MSK
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

# nc cwillu.com 10101 < /dev/kmsg
after operations 6,7,8,9 - http://cwillu.com:8080/128.0.141.47/2

$ sudo dmesg | nc termbin.com 9999
https://termbin.com/6g54


Best regards,
Aleksey Utkin