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Breaking locks

You can use the lock break command to break file locks. This enables you to correct issues where a file lock prevents client access to files.

Locking prevents multiple processes from modifying the same file at the same time and allows cooperating processes to synchronize access to shared files. Data ONTAP manages locks across the multiprotocol environment.

Sometimes the need arises to manually break locks. An example of a scenario in which you might need to break locks include when you are debugging applications. The lock break command manages locks for CIFS, NFSv4, NLM (used with NFSv2 and NFSv3), and FLEXCACHE.

The lock break command has five subcommands that serve as filters in determining which locks to break. Three of the subcommands have optional parameters that provide finer granularity in determining which locks to break, allowing you to break only the locks that you choose without breaking other locks that you want to remain intact. You cannot use the lock break command without including one of the available subcommands.

To determine which locks you want to break, you can display information about currently held locks using the lock status command. The man page for the lock command contains detailed information.

Note: If you issue a lock break command on files that CIFS clients have currently opened, the CIFS clients must close and reopen the files to be able to further modify them. This is required because breaking locks invalidates the file handles. CIFS clients receive a new valid file handle after reopening the files.