NFS41: make PNFS_BLOCK selectable

PNFS_BLOCK needs BLK_DEV_DM/MD, which is not a dependency for other
pnfs layout drivers. Seperate it out so others can still build when
BLK_DEV_DM/MD is not enabled.

Also change select to depends on to avoid build failures.

Reported-and-tested-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Peng Tao <peng_tao@emc.com>
Acked-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index be020771c6b4..0d306131706d 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -79,12 +79,9 @@ config NFS_V4_1
         depends on NFS_FS && NFS_V4 && EXPERIMENTAL
         select SUNRPC_BACKCHANNEL
         select PNFS_FILE_LAYOUT
-        select PNFS_BLOCK
-        select MD
-        select BLK_DEV_DM
         help
           This option enables support for minor version 1 of the NFSv4 protocol
-          (RFC 5661 and RFC 5663) in the kernel's NFS client.
+          (RFC 5661) in the kernel's NFS client.
 
           If unsure, say N.
 
@@ -92,7 +89,14 @@ config PNFS_FILE_LAYOUT
         tristate
 
 config PNFS_BLOCK
-        tristate
+        tristate "Provide support for the pNFS Block Layout Driver for NFSv4.1 pNFS (EXPERIMENTAL)"
+        depends on NFS_FS && NFS_V4_1 && BLK_DEV_DM
+        help
+          Say M here if you want your pNFS client to support the Block Layout Driver
+          (RFC 5663). Requires Multiple devices driver support (DM) and Device mapper
+          support (BLK_DEV_DM).
+
+          If unsure, say N.
 
 config PNFS_OBJLAYOUT
         tristate "Provide support for the pNFS Objects Layout Driver for NFSv4.1 pNFS (EXPERIMENTAL)"