doc: document earmark option for subvolume and new commands

Signed-off-by: Avan Thakkar <[email protected]>

Author: avanthakkar

doc/cephfs/fs-volumes.rst

@@ -276,7 +276,7 @@ Use a command of the following form to create a subvolume:
 
 .. prompt:: bash #
 
-   ceph fs subvolume create <vol_name> <subvol_name> [--size <size_in_bytes>] [--group_name <subvol_group_name>] [--pool_layout <data_pool_name>] [--uid <uid>] [--gid <gid>] [--mode <octal_mode>] [--namespace-isolated]
+   ceph fs subvolume create <vol_name> <subvol_name> [--size <size_in_bytes>] [--group_name <subvol_group_name>] [--pool_layout <data_pool_name>] [--uid <uid>] [--gid <gid>] [--mode <octal_mode>] [--namespace-isolated] [--earmark <earmark>]
 
 
 The command succeeds even if the subvolume already exists.
@@ -289,6 +289,15 @@ The subvolume can be created in a separate RADOS namespace by specifying the
 default subvolume group with an octal file mode of ``755``, a uid of its
 subvolume group, a gid of its subvolume group, a data pool layout of its parent
 directory, and no size limit.
+You can also assign an earmark to a subvolume using the ``--earmark`` option.
+The earmark is a unique identifier that tags the subvolume for specific purposes,
+such as NFS or SMB services. By default, no earmark is set, allowing for flexible
+assignment based on administrative needs. An empty string ("") can be used to remove
+any existing earmark from a subvolume.
+
+The earmarking mechanism ensures that subvolumes are correctly tagged and managed,
+helping to avoid conflicts and ensuring that each subvolume is associated
+with the intended service or use case.
 
 Removing a subvolume
 ~~~~~~~~~~~~~~~~~~~~
@@ -418,6 +427,7 @@ The output format is JSON and contains the following fields.
 * ``pool_namespace``: RADOS namespace of the subvolume
 * ``features``: features supported by the subvolume
 * ``state``: current state of the subvolume
+* ``earmark``: earmark of the subvolume
 
 If a subvolume has been removed but its snapshots have been retained, the
 output contains only the following fields.
@@ -522,6 +532,33 @@ subvolume using the metadata key:
 Using the ``--force`` flag allows the command to succeed when it would
 otherwise fail (if the metadata key did not exist).
 
+Getting earmark of a subvolume
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Use a command of the following form to get the earmark of a subvolume:
+
+.. prompt:: bash #
+
+   ceph fs subvolume earmark get <vol_name> <subvol_name> [--group_name <subvol_group_name>]
+
+Setting earmark of a subvolume
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Use a command of the following form to set the earmark of a subvolume:
+
+.. prompt:: bash #
+
+   ceph fs subvolume earmark set <vol_name> <subvol_name> [--group_name <subvol_group_name>] <earmark>
+
+Removing earmark of a subvolume
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Use a command of the following form to remove the earmark of a subvolume:
+
+.. prompt:: bash #
+
+   ceph fs subvolume earmark rm <vol_name> <subvol_name> [--group_name <subvol_group_name>]
+
 Creating a Snapshot of a Subvolume
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~