lock

Locking an entire VOB disables all write operations to that VOB and forces a database checkpoint by causing a state flush. A typical application is locking a VOB to prevent it from being modified during backup.

You must lock a VOB before backing it up, and you cannot use the –nusers option. With –nusers, it is possible that the VOB will be modified during the backup, and locking with the –nuser option does not perform a database checkpoint.

In general, locking a type object disables these kinds of operations:

• Operations that create, delete, or modify instances of the type
• Operations that delete or modify the type object itself (for example, renaming it)

The following sections describe how these general rules apply to the different kinds of type objects.

• Element type. If an element type is locked, you cannot do the following:
  • Use the type in an rmtype or rename command
  • Create an element of that type with mkelem or mkdir
  • Change an existing element to that type with chtype
  • Modify the element's version tree with checkout, checkin, or mkbranch
• Branch type. If a branch type (as opposed to an instance of a branch type) is locked, you cannot do the following:
  • Use the type in an rmtype, rename, or mkbrtype –replace command
  • Create a branch of that type with mkbranch
  • Rename (that is, change the type of) an existing branch to or from that type with chtype
  • Modify the branch with checkout or checkin
  • Cancel a checkout using uncheckout
  • Remove an attribute using rmattr or mkattr -replace

    You can create a subbranch at any version on a locked branch, using mkbranch. (Creating a subbranch does not modify the branch itself.)

• Label type. If a label type is locked, you cannot do the following:
  • Use the type in an rmtype, rename, or mklbtype –replace command
  • Attach or remove a version label of that type with mklabel or rmlabel (This includes moving a label from one version to another with mklabel –replace.)
• Attribute type. If an attribute type is locked, you cannot do the following:
  • Use the type in an rmtype, rename, or mkattype –replace command
  • Attach or remove an attribute of that type with mkattr or rmattr (This includes moving an attribute from one version to another with mkattr –replace.)
• Hyperlink type. If a hyperlink type is locked, you cannot do the following:
  • Use the type in an rmtype, rename, or mkhltype –replace command
  • Create or remove a hyperlink of that type with mkhlink or rmhlink
• Trigger type. If a trigger type is locked, you cannot do the following:
  • Use the type in an rmtype, rename, or mktrtype –replace command
  • (If created with mktrtype –element) Create or remove a trigger of that type with mktrigger or rmtrigger

  In general, locking a trigger type does not inhibit triggers of that type from firing. Exception: Trigger firing is inhibited if a trigger type created with mktrtype –element –all, mktrtype –ucm –all or if mktrtype –type is made obsolete (using lock –obsolete).

If a branch instance is locked, you cannot do the following:

• Rename (that is, change the type of) the branch with chtype
• Modify the branch with checkout or checkin
• Cancel a checkout using uncheckout
• Attach a label to a version on the branch using mklabel
• Remove a label from a version on the branch using rmlabel or mklabel -replace
• Attach an attribute using mkattr
• Remove an attribute using rmattr or mkattr -replace

  You can create a subbranch at any version on a locked branch, using mkbranch. (Creating a subbranch does not modify the branch itself.)

If a version is locked, you cannot do the following:

• Attach a label using mklabel
• Remove a label using rmlabel or mklabel -replace
• Attach an attribute using mkattr
• Remove an attribute using rmattr or mkattr -replace
• Remove the version using rmver

You must always specify an explicit version to lock or unlock.

Locking a VOB storage pool inhibits commands that create or remove the pool's data containers. It also prevents the pool's scrubbing parameters from being modified with mkpool –update. The following sections describe how this principle applies to the different kinds of storage pools.

• Source pool. If a source storage pool is locked, you cannot do the following:
  • Create an element that would be assigned to that pool, with mkelem or mkdir. (A new element inherits its pool assignments from its parent directory element.)
  • Change an existing element's pool assignment to or from that pool, with chpool.
  • Change an element's element type with chtype, if the change would require recreation of source data containers (for example, changing from type file to type text_file).
  • Check in a new version of an element assigned to that pool.
  • Create or remove a branch of an element assigned to that pool, with mkbranch or rmbranch.
  • Remove a version of an element assigned to that pool, or remove the element itself, with rmver or rmelem.
• Derived object pool. If a derived object storage pool is locked:
  • clearmake cannot winkin a previously unshared derived object in a directory assigned to that pool. (The invocation of promote_server to copy the data container from view-private storage to the derived object storage pool fails.)
  • scrubber cannot remove data containers from the pool.
  • An rmdo command fails for a derived object whose data container is in that pool.
• Cleartext pool. If a cleartext storage pool is locked, an attempt to read a version of an element assigned to that pool may fail. (It fails if a new cleartext data container for that version would have been created and cached in the cleartext pool.)

An object becomes obsolete if it is processed with a lock –obsolete command. An obsolete type object or obsolete storage pool is not only locked, but is also invisible to certain forms of the lstype, lslock, lspool, and lsvtree commands. An obsolete VOB or obsolete VOB object is no different from one with an ordinary lock. You can change an object's status from obsolete to locked by using a lock –replace command:

Similarly, you can use a lock –replace command to make a locked object obsolete.

The unlock command removes a lock from an object, reenabling the previously prohibited operations.