[options="header"]
|====
| f_type | value
-| EXT?_SUPER_MAGIC (ldiskfs) | 0xEF53
+| EXT4_SUPER_MAGIC (ldiskfs) | 0xEF53
| ZFS_SUPER_MAGIC | 0x2fc12fc1
|====
The 'os_bfree' field is the number of blocks not currently in use.
The 'os_bavail' is the number of blocks available to be allocated to
-new files.
+new files. The number of available blocks is typically lower than
+the number of free blocks due to <<grant>> and blocks reserved for
+target internal usage such as metadata.
The 'os_files' field is the total number of files on the target, both
allocated and free. For some OSD types this is a static number, and
The 'os_fsid' is intended to be the target backing device UUID in
ASCII format. The current osd-ldiskfs and osd-zfs implementations
-don't fill this in.
+do not fill this field in.
The 'os_bsize' field is the block size in bytes. This is for computing
-the total, free, and available space in combination with os_blocks,
-os_bfree, and os_bavail respectively. It does not necessarily
+the total, free, and available space in combination with 'os_blocks',
+'os_bfree', and 'os_bavail' respectively. It does not necessarily
represent the minimum or optimal IO size.
The 'os_namelen' field gives the maximum name length for files on the
-back-end file system.
+back-end file system in bytes.
The 'os_maxbytes' field is the maximum size of a single object
(i.e. the maximum byte offset that can be written to). This is the
In normal operation the 'os_state' value is returned as 0x0. If the
back-end file system has a RAID configuration that is degraded or
rebuilding the state is returned with the OS_STATE_DEGRADED (0x1) flag
-set. If the file system has been set to read-only, for whatever
-reason, then the state is returned with the OS_STATE_READONLY (0x2)
-flag set, for example if it was explicitly mounted read-only, or
+set. If the file system has been set to read-only, either manually at
+mount or automatcially due to detected corruption of the underlying
+target filesystem, then 'os_state' is returned with OS_STATE_READONLY (0x2)
+set, for example if it was explicitly mounted read-only, or
corruption has been detected at runtime in the backing filesystem.
The 'os_fprecreated' field counts the number of pre-created objects