/usr/bin/blkpr

Usage:
 blkpr [options] <device>

Manage persistent reservations on a device.

Options:
 -c, --command <cmd>      command for persistent reservations
 -k, --key <num>          key to operate on
 -K, --oldkey <num>       old key to operate on
 -f, --flag <flag>        command flag
 -t, --type <type>        command type

 -h, --help               display this help
 -V, --version            display version

Arguments:

 <cmd> is a command; available commands are:
  * register:
    This command registers a new reservation if the key argument
    is non-null. If no existing reservation exists oldkey must be zero, if
    an existing reservation should be replaced oldkey must contain the old
    reservation key. If the key argument is 0 it unregisters the existing
    reservation passed in oldkey.

  * reserve:
    This command reserves the device and thus restricts access for other devices
    based on the type argument.  The key argument must be the existing
    reservation key for the device as acquired by the register, preempt,
    preempt-abort commands.

  * release:
    This command releases the reservation specified by key and flags and thus
    removes any access restriction implied by it.

  * preempt:
    This command releases the existing reservation referred to by old_key and
    replaces it with a new reservation of type for the reservation key key.

  * preempt-abort:
    This command works like preempt except that it also aborts any outstanding
    command sent over a connection identified by oldkey.

  * clear:
    This command unregisters both key and any other reservation key registered
    with the device and drops any existing reservation.

  * read-keys:
    This command lists reservation keys currently registered with the device.

  * read-reservation:
    This command shows the current reservation.

 <flag> is a command flag; available flags are:
  * ignore-key:
    Ignore the existing reservation key.  This is commonly supported for
    register command, and some implementation may support the flag for reserve
    command.

 <type> is a command type; available types are:
  * write-exclusive:
    Only the initiator that owns the reservation can write to the device. Any
    initiator can read from the device.

  * exclusive-access:
    Only the initiator that owns the reservation can access the device.

  * write-exclusive-reg-only:
    Only initiators with a registered key can write to the device, any initiator
    can read from the device.

  * exclusive-access-reg-only:
    Only initiators with a registered key can access the device.

  * write-exclusive-all-regs:
    Only initiators with a registered key can write to the device. Any
    initiator can read from the device.  All initiators with a registered
    key are considered reservation holders.  Please reference the SPC spec
    on the meaning of a reservation holder if you want to use this type.

  * exclusive-access-all-regs:
    Only initiators with a registered key can access the device. All initiators
    with a registered key are considered reservation holders. Please reference
    the SPC spec on the meaning of a reservation holder if you want to use this
    type.

For more details see blkpr(8).