Bug 10476

Summary: Loop mount fails with "Device or resource busy"
Product: Busybox Reporter: Mukuntha Rajaa <mukuntharajaa>
Component: Standard ComplianceAssignee: unassigned
Status: NEW ---    
Severity: normal CC: busybox-cvs
Priority: P5    
Version: 1.27.x   
Target Milestone: ---   
Hardware: All   
OS: Linux   
Host: Target:
Build:

Description Mukuntha Rajaa 2017-11-02 10:17:08 UTC 
Kernel:
4.4.84

Busybox:
1.27.2
# busybox --help
BusyBox v1.27.2 (2017-10-24 09:15:48 UTC) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
Licensed under GPLv2. See source distribution for detailed
copyright notices.

Failure log:
# mount -o loop /dev/VG_CFPU-0/config-R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465-INITIAL /mnt/backup/
mount: mounting /dev/VG_CFPU-0/config-R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465-INITIAL on /mnt/backup/ failed: Device or resource busy

Tried to mount same device using util-linux based mount:
# /tmp/mount -o loop /dev/VG_CFPU-0//config-R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465-INITIAL /media
# umount /media/

# ls -l /dev/VG_CFPU-0/config-R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465-INITIAL
lrwxrwxrwx 1 root root 8 Oct 30 08:25 /dev/VG_CFPU-0/config-R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465-INITIAL -> ../dm-18


# ls -l /sys/block/dm-18/bdi
lrwxrwxrwx 1 root root 0 Jan  1  1970 /sys/block/dm-18/bdi -> ../../bdi/254:18

# dmsetup info --major 254 --minor 18
Name:              VG_CFPU--0-config--R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465--INITIAL
State:             ACTIVE
Read Ahead:        256
Tables present:    LIVE
Open count:        1
Event number:      0
Major, minor:      254, 18
Number of targets: 1
UUID: LVM-aJsWNy2EjYfs55iCKOmvQ4tNVbVoJESGp17pTo25YwNhumN0C2hhZCno0Z8dGp3o


# mount -o loop /dev/mapper/VG_CFPU--0-config--R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465--INITIAL /mnt/backup/
mount: mounting /dev/mapper/VG_CFPU--0-config--R_FPT_180.0.1.36.WR.bcn.rm.1710290936.408465--INITIAL on /mnt/backup/ failed: Device or resource busy