It appears that mkfs.btrfs doesn't like the loop device, /dev/loop0 which has a deleted backing file.
root@ubuntu:~# cat /sys/block/loop0/loop/backing_file
/root.tmp.img (deleted)
root@ubuntu:~# ls -al /root.tmp.img
ls: cannot access /root.tmp.img: No such file or directory
# lsb_release -rd
Description: Ubuntu 14.04.5 LTS
Release: 14.04
# apt-cache policy btrfs-tools archive. ubuntu. com/ubuntu/ trusty-updates/main amd64 Packages dpkg/status archive. ubuntu. com/ubuntu/ trusty/main amd64 Packages
btrfs-tools:
Installed: 3.12-1ubuntu0.1
Candidate: 3.12-1ubuntu0.1
Version table:
*** 3.12-1ubuntu0.1 0
500 http://
100 /var/lib/
3.12-1 0
500 http://
# mkfs.btrfs --force /dev/vdd succeeds
# # mkfs.btrfs --force /dev/vdd
Error: error checking /dev/vdd mount status
# strace -f mkfs.btrfs --force /dev/vdd S_IFBLK| 0660, st_rdev=makedev(7, 0), ...}) = 0 S_IFDIR| 0755, st_size=4180, ...}) = 0 S_IFBLK| 0660, st_rdev=makedev(7, 0), ...}) = 0 sys/block/ /loop0/ loop/backing_ file", O_RDONLY) = 5 S_IFREG| 0444, st_size=4096, ...}) = 0 PROT_WRITE, MAP_PRIVATE| MAP_ANONYMOUS, -1, 0) = 0x7fe8bd73c000 0x7fe8bd73c000, 4096) = 0 S_IFDIR| 0755, st_size=4180, ...}) = 0 S_IFBLK| 0660, st_rdev= makedev( 253, 48), ...}) = 0 /root.tmp. img (deleted)", 0x7ffeaa3f0bf0) = -1 ENOENT (No such file or directory) 0x7fe8bd73d000, 4096) = 0
<snip>
stat("/dev/loop0", {st_mode=
lstat("/dev", {st_mode=
lstat("/dev/loop0", {st_mode=
open("/
fstat(5, {st_mode=
mmap(NULL, 4096, PROT_READ|
read(5, "/root.tmp.img (deleted)\n", 4096) = 24
close(5) = 0
munmap(
lstat("/dev", {st_mode=
lstat("/dev/vdd", {st_mode=
lstat("
close(4) = 0
munmap(
close(3) = 0
write(2, "Error: error checking /dev/vdd m"..., 44Error: error checking /dev/vdd mount status
) = 44
exit_group(1) = ?
+++ exited with 1 +++
It appears that mkfs.btrfs doesn't like the loop device, /dev/loop0 which has a deleted backing file.
root@ubuntu:~# cat /sys/block/ loop0/loop/ backing_ file
/root.tmp.img (deleted)
root@ubuntu:~# ls -al /root.tmp.img
ls: cannot access /root.tmp.img: No such file or directory
ProblemType: Bug ature: Ubuntu 3.13.0- 135.184- generic 3.13.11-ckt39
DistroRelease: Ubuntu 14.04
Package: btrfs-tools 3.12-1ubuntu0.1
ProcVersionSign
Uname: Linux 3.13.0-135-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.27
Architecture: amd64
Date: Wed Nov 29 02:58:04 2017
ProcEnviron:
TERM=vt102
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: btrfs-tools
UpgradeStatus: No upgrade log present (probably fresh install)