chore(doc): adding btrfs filesystem in the doc

Signed-off-by: Pawan <[email protected]>

README.md

@@ -106,9 +106,9 @@ parameters you want. In case, zfs properties paramenters are not provided, the v
 Also currently supported fs types are ext2/3/4, xfs and zfs only. The *poolname* is the must argument.
 Also there must be a ZPOOL running on *all the nodes* with the name given in the storage class.
 
-##### ext2/3/4 or xfs as FsType
+##### ext2/3/4 or xfs or btrfs as FsType
 
-If we provide fstype as ext2/3/4 or xfs, the driver will create a ZVOL, which is a blockdevice carved out of ZFS Pool.
+If we provide fstype as ext2/3/4 or xfs or btrfs, the driver will create a ZVOL, which is a blockdevice carved out of ZFS Pool.
 This blockdevice will again formatted as corresponding filesystem(ext2/3/4 or xfs). In this way applications will get desired filesystem.
 Here, in this case there will be a filesystem layer on top of ZFS filesystem, and applications may not get the optimal performance.
 The sample storage class for ext4 fstype is provided below :-

docs/resize.md

@@ -4,6 +4,8 @@ We can resize the volume by updating the PVC yaml to the desired size and apply
 
 For resize, storageclass that provisions the pvc must support resize. We should have allowVolumeExpansion as true in storageclass
 
+Note: btrfs does not support online volume resize, so we can not resize the btrfs volumes.
+
 ```
 $ cat sc.yaml