Dump ocfs2 file system information on disk.
o2info [-C|--cluster-coherent] [--fs-features] [--volinfo] [--mkfs] <device or file>
o2info is designed to be an information tool, to display OCFS2 file system information on disk. Its main goal on one hand, is to provide a tool to display fs info in a comprehensive way and providing the information which may be missing in debugfs.ocfs and tunefs.ocfs2 such as global bitmap free space fragmentation and free inode info for each slot, on the other hand, it also aims to become a info tool(not an administration one), which therefore allows all users who may have no read privilege on the underlying device to use the utility. In practice, 'o2info /path/to/file/on/ocfs2/vol' use a new OCFS2_IOC_INFO ioctl to get info from fs for a mounted case. For a privileged user(e.g, root), the same info however, can also be accessed by 'o2info /dev/sdxN' to direcly manipulate the raw device.
-C, --cluster-coherent
Enable cluster (in)coherency for mounted case, means it will attempt to acquire a global PR lock when querying info from a cluster filesystem, which may degrade the performance, default is none cluster-coherency.
--fs-features
List all compat, incompat and ro-compat fs features on OCFS2 filesystem.
--volinfo
Dump basic volume information, such as blocksize, clustersize, volume label and UUID etc.
--mkfs
Dump an original format of mkfs.ocfs's arguments, importantly, which can be used directly as a fresh mkfs retry: #mkfs.ocfs2 "$(o2info --mkfs /dev/name/or/path/of/file)" /dev/sdaX
-V, --version
Show version and exit.
-h, --help
Display help and exit.
[oracle@node1 ~]# o2info --volinfo /storage/testfile # For none-privileged users.
[root@node1 ~]# o2info --volinfo /dev/sda1
Label: ocfs2-volume
UUID: 976D8E630B3A4F1F95497311A92901FC
Block Size: 4096
Cluster Size: 4096
Node Slots: 4
Features: backup-super strict-journal-super sparse inline-data xattr
Features: unwritten
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