xfs_freeze suspends and resumes access to an XFS filesystem (see xfs(5)).
xfs_freeze halts new access to the filesystem and creates a stable image on disk. xfs_freeze is intended
to be used with volume managers and hardware RAID devices that support the creation of snapshots.
The mount-point argument is the pathname of the directory where the filesystem is mounted. The
filesystem must be mounted to be frozen (see mount(8)).
The -f flag requests the specified XFS filesystem to be frozen from new modifications. When this is
selected, all ongoing transactions in the filesystem are allowed to complete, new write system calls are
halted, other calls which modify the filesystem are halted, and all dirty data, metadata, and log
information are written to disk. Any process attempting to write to the frozen filesystem will block
waiting for the filesystem to be unfrozen.
Note that even after freezing, the on-disk filesystem can contain information on files that are still in
the process of unlinking. These files will not be unlinked until the filesystem is unfrozen or a clean
mount of the snapshot is complete.
The -u flag is used to un-freeze the filesystem and allow operations to continue. Any filesystem
modifications that were blocked by the freeze are unblocked and allowed to complete.
The -V flag prints the version number and exits.
Unless -V is specified, one of -f or -u must be supplied to xfs_freeze.