xfs: Improve CONFIG_XFS_RT Kconfig help

Improve the description of the XFS_RT configuration option to document
that this option is required for zoned block devices.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig
index 8930d5254e1da61d836b04996332e828c6d5f01f..d66d517c99a921661c88cffd8e0b8a2d74be422c 100644 (file)
--- a/fs/xfs/Kconfig
+++ b/fs/xfs/Kconfig
@@ -119,6 +119,15 @@ config XFS_RT
 
          See the xfs man page in section 5 for additional information.
 
+         This option is mandatory to support zoned block devices. For these
+         devices, the realtime subvolume must be backed by a zoned block
+         device and a regular block device used as the main device (for
+         metadata). If the zoned block device is a host-managed SMR hard-disk
+         containing conventional zones at the beginning of its address space,
+         XFS will use the disk conventional zones as the main device and the
+         remaining sequential write required zones as the backing storage for
+         the realtime subvolume.
+
          If unsure, say N.
 
 config XFS_DRAIN_INTENTS