Bug 254210

Sometimes it is necessary to share the same directory between jails and in this case there is a issue with free up space after deleting a files.

For example, the file created in jail A and then deleted in jail B will not free up space as long as jail A is running.

# cat /etc/fstab.test1
/storage/data   /usr/jail/test1/storage/data    nullfs          rw,noatime      0       0

# cat /etc/fstab.test2
/storage/data   /usr/jail/test2/storage/data    nullfs          rw,noatime      0       0

# cat /etc/jail.conf
path = "/usr/jail/${name}";
exec.clean;
exec.start      = "sh /etc/rc";
exec.stop       = "sh /etc/rc.shutdown jail";
host.hostname   = "${name}";
mount.fstab     = "/etc/fstab.${name}";
mount.devfs;
test1 {
}
test2 {
}

# df -ht ufs
Filesystem    Size    Used   Avail Capacity  Mounted on
/dev/da0p2    8.9G    3.2G    5.0G    39%    /

# service jail start
Starting jails: test1 test2.

# df -ht ufs
Filesystem    Size    Used   Avail Capacity  Mounted on
/dev/da0p2    8.9G    3.2G    5.0G    39%    /

# jexec test1 dd if=/dev/random of=/storage/data/random.dd bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes transferred in 3.723429 secs (288374490 bytes/sec)

# df -ht ufs
Filesystem    Size    Used   Avail Capacity  Mounted on
/dev/da0p2    8.9G    4.2G    4.0G    52%    /

# jexec test2 rm /storage/data/random.dd

# df -ht ufs
Filesystem    Size    Used   Avail Capacity  Mounted on
/dev/da0p2    8.9G    4.2G    4.0G    52%    /

# service jail stop test2
Stopping jails: test2.

# df -ht ufs
Filesystem    Size    Used   Avail Capacity  Mounted on
/dev/da0p2    8.9G    4.2G    4.0G    52%    /

# service jail stop test1
Stopping jails: test1.

# df -ht ufs
Filesystem    Size    Used   Avail Capacity  Mounted on
/dev/da0p2    8.9G    3.2G    5.0G    39%    /