[PATCH v3] nfs: split up block layout and SCSI layout support

[Scott Mayhew <smayhew@redhat.com>]

Add two new config options PNFS_BLOCK_LAYOUT and PNFS_SCSI_LAYOUT so
that SCSI layouts can be enabled without requiring block layouts.
Since block layouts are considered deprecated, PNFS_BLOCK_LAYOUT
is off by default.

The original PNFS_BLOCK config is now invisible and gets selected when
either of PNFS_BLOCK_LAYOUT or PNFS_SCSI_LAYOUT are enabled.

Also added a dependency on BLOCK to the Kconfig to fix undefined symbol
warnings from the kernel test robot.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
v3 changes:
- Make PNFS_BLOCK_LAYOUT and PNFS_SCSI_LAYOUT select PNFS_BLOCK instead
  of having PNFS_BLOCK depend on PNFS_BLOCK_LAYOUT or PNFS_SCSI_LAYOUT
- Remove redundant 'default n' from PNFS_BLOCK_LAYOUT
- Shuffled stuff around in blocklayout.c to reduce the number of ifdefs
- Added separate helpers to blocklayout.c for registering/unregistering
  the blocklayout and scsilayout types, along with stubs for when
  either of those are disabled
- In dev.c, wrapped blocklayout-specific and scsilayout-specific
  functions in appropriate ifdef blocks and created the necessary stubs
  for when either of those are disabled.
- Added dependency on BLOCK to the Kconfig to fix undefined symbol
  warnings from the kernel test robot

 fs/nfs/Kconfig                   |  17 ++++-
 fs/nfs/blocklayout/Makefile      |   3 +-
 fs/nfs/blocklayout/blocklayout.c | 113 ++++++++++++++++++++++---------
 fs/nfs/blocklayout/dev.c         |  32 ++++++++-
 4 files changed, 129 insertions(+), 36 deletions(-)

diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 6bb30543eff0..64c249f800a9 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -123,8 +123,23 @@ config PNFS_FILE_LAYOUT
 
 config PNFS_BLOCK
 	tristate
-	depends on NFS_V4 && BLK_DEV_DM
+
+config PNFS_BLOCK_LAYOUT
+	bool "NFS client support for pNFS block layouts"
+	depends on NFS_V4 && BLOCK && BLK_DEV_DM
+	select PNFS_BLOCK
+	help
+	  Enable support for the pNFS block-volume layout type (RFC 5663).
+
+	  If unsure, say N.
+
+config PNFS_SCSI_LAYOUT
+	bool "NFS client support for pNFS SCSI layouts"
+	depends on NFS_V4 && BLOCK
 	default NFS_V4
+	select PNFS_BLOCK
+	help
+	  Enable suport for the pNFS SCSI layout type (RFC 8154).
 
 config PNFS_FLEXFILE_LAYOUT
 	tristate
diff --git a/fs/nfs/blocklayout/Makefile b/fs/nfs/blocklayout/Makefile
index 7668a1bfb5fa..3403cb7fe201 100644
--- a/fs/nfs/blocklayout/Makefile
+++ b/fs/nfs/blocklayout/Makefile
@@ -4,4 +4,5 @@
 #
 obj-$(CONFIG_PNFS_BLOCK) += blocklayoutdriver.o
 
-blocklayoutdriver-y += blocklayout.o dev.o extent_tree.o rpc_pipefs.o
+blocklayoutdriver-y += blocklayout.o dev.o extent_tree.o
+blocklayoutdriver-$(CONFIG_PNFS_BLOCK_LAYOUT) += rpc_pipefs.o
diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index d54a141a89b3..680b3b343859 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -470,18 +470,6 @@ static struct pnfs_layout_hdr *__bl_alloc_layout_hdr(struct inode *inode,
 	return &bl->bl_layout;
 }
 
-static struct pnfs_layout_hdr *bl_alloc_layout_hdr(struct inode *inode,
-						   gfp_t gfp_flags)
-{
-	return __bl_alloc_layout_hdr(inode, gfp_flags, false);
-}
-
-static struct pnfs_layout_hdr *sl_alloc_layout_hdr(struct inode *inode,
-						   gfp_t gfp_flags)
-{
-	return __bl_alloc_layout_hdr(inode, gfp_flags, true);
-}
-
 static void bl_free_lseg(struct pnfs_layout_segment *lseg)
 {
 	dprintk("%s enter\n", __func__);
@@ -954,6 +942,13 @@ static const struct nfs_pageio_ops bl_pg_write_ops = {
 	.pg_cleanup = pnfs_generic_pg_cleanup,
 };
 
+#ifdef CONFIG_PNFS_BLOCK_LAYOUT
+static struct pnfs_layout_hdr *bl_alloc_layout_hdr(struct inode *inode,
+						   gfp_t gfp_flags)
+{
+	return __bl_alloc_layout_hdr(inode, gfp_flags, false);
+}
+
 static struct pnfs_layoutdriver_type blocklayout_type = {
 	.id				= LAYOUT_BLOCK_VOLUME,
 	.name				= "LAYOUT_BLOCK_VOLUME",
@@ -978,6 +973,48 @@ static struct pnfs_layoutdriver_type blocklayout_type = {
 	.sync				= pnfs_generic_sync,
 };
 
+static int __init pnfs_register_blocklayout(void)
+{
+	int ret;
+
+	ret = bl_init_pipefs();
+	if (ret)
+		return ret;
+
+	ret = pnfs_register_layoutdriver(&blocklayout_type);
+	if (ret) {
+		bl_cleanup_pipefs();
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit pnfs_unregister_blocklayout(void)
+{
+	pnfs_unregister_layoutdriver(&blocklayout_type);
+	bl_cleanup_pipefs();
+}
+
+MODULE_ALIAS("nfs-layouttype4-3");
+#else
+static int __init pnfs_register_blocklayout(void)
+{
+	return 0;
+}
+
+static void __exit pnfs_unregister_blocklayout(void)
+{
+}
+#endif /* CONFIG_PNFS_BLOCK_LAYOUT */
+
+#ifdef CONFIG_PNFS_SCSI_LAYOUT
+static struct pnfs_layout_hdr *sl_alloc_layout_hdr(struct inode *inode,
+						   gfp_t gfp_flags)
+{
+	return __bl_alloc_layout_hdr(inode, gfp_flags, true);
+}
+
 static struct pnfs_layoutdriver_type scsilayout_type = {
 	.id				= LAYOUT_SCSI,
 	.name				= "LAYOUT_SCSI",
@@ -1002,6 +1039,28 @@ static struct pnfs_layoutdriver_type scsilayout_type = {
 	.sync				= pnfs_generic_sync,
 };
 
+static int __init pnfs_register_scsilayout(void)
+{
+	return pnfs_register_layoutdriver(&scsilayout_type);
+}
+
+static void __exit pnfs_unregister_scsilayout(void)
+{
+	pnfs_unregister_layoutdriver(&scsilayout_type);
+}
+
+MODULE_ALIAS("nfs-layouttype4-5");
+#else
+static int __init pnfs_register_scsilayout(void)
+{
+	return 0;
+}
+
+static void __exit pnfs_unregister_scsilayout(void)
+{
+}
+#endif /* CONFIG_PNFS_SCSI_LAYOUT */
+
 
 static int __init nfs4blocklayout_init(void)
 {
@@ -1009,25 +1068,17 @@ static int __init nfs4blocklayout_init(void)
 
 	dprintk("%s: NFSv4 Block Layout Driver Registering...\n", __func__);
 
-	ret = bl_init_pipefs();
+	ret = pnfs_register_blocklayout();
 	if (ret)
-		goto out;
+		return ret;
 
-	ret = pnfs_register_layoutdriver(&blocklayout_type);
-	if (ret)
-		goto out_cleanup_pipe;
+	ret = pnfs_register_scsilayout();
+	if (ret) {
+		pnfs_unregister_blocklayout();
+		return ret;
+	}
 
-	ret = pnfs_register_layoutdriver(&scsilayout_type);
-	if (ret)
-		goto out_unregister_block;
 	return 0;
-
-out_unregister_block:
-	pnfs_unregister_layoutdriver(&blocklayout_type);
-out_cleanup_pipe:
-	bl_cleanup_pipefs();
-out:
-	return ret;
 }
 
 static void __exit nfs4blocklayout_exit(void)
@@ -1035,13 +1086,9 @@ static void __exit nfs4blocklayout_exit(void)
 	dprintk("%s: NFSv4 Block Layout Driver Unregistering...\n",
 	       __func__);
 
-	pnfs_unregister_layoutdriver(&scsilayout_type);
-	pnfs_unregister_layoutdriver(&blocklayout_type);
-	bl_cleanup_pipefs();
+	pnfs_unregister_scsilayout();
+	pnfs_unregister_blocklayout();
 }
 
-MODULE_ALIAS("nfs-layouttype4-3");
-MODULE_ALIAS("nfs-layouttype4-5");
-
 module_init(nfs4blocklayout_init);
 module_exit(nfs4blocklayout_exit);
diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index c926b7e43827..00462e6affb1 100644
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -15,6 +15,7 @@
 
 #define NFSDBG_FACILITY		NFSDBG_PNFS_LD
 
+#ifdef CONFIG_PNFS_SCSI_LAYOUT
 static void bl_unregister_scsi(struct pnfs_block_dev *dev)
 {
 	struct block_device *bdev = file_bdev(dev->bdev_file);
@@ -45,6 +46,16 @@ static bool bl_register_scsi(struct pnfs_block_dev *dev)
 	trace_bl_pr_key_reg(bdev, dev->pr_key);
 	return true;
 }
+#else
+static void bl_unregister_scsi(struct pnfs_block_dev *dev)
+{
+}
+
+static bool bl_register_scsi(struct pnfs_block_dev *dev)
+{
+	return false;
+}
+#endif /* CONFIG_PNFS_SCSI_LAYOUT */
 
 static void bl_unregister_dev(struct pnfs_block_dev *dev)
 {
@@ -292,7 +303,7 @@ static int
 bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask);
 
-
+#ifdef CONFIG_PNFS_BLOCK_LAYOUT
 static int
 bl_parse_simple(struct nfs_server *server, struct pnfs_block_dev *d,
 		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
@@ -320,7 +331,17 @@ bl_parse_simple(struct nfs_server *server, struct pnfs_block_dev *d,
 		file_bdev(bdev_file)->bd_disk->disk_name);
 	return 0;
 }
+#else
+static int
+bl_parse_simple(struct nfs_server *server, struct pnfs_block_dev *d,
+                struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
+{
+	dprintk("unsupported volume type: %d\n", PNFS_BLOCK_VOLUME_SIMPLE);
+	return -EIO;
+}
+#endif /* CONFIG_PNFS_BLOCK_LAYOUT */
 
+#ifdef CONFIG_PNFS_SCSI_LAYOUT
 static bool
 bl_validate_designator(struct pnfs_block_volume *v)
 {
@@ -449,6 +470,15 @@ bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
 	d->bdev_file = NULL;
 	return error;
 }
+#else
+static int
+bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
+		struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
+{
+	dprintk("unsupported volume type: %d\n", PNFS_BLOCK_VOLUME_SCSI);
+	return -EIO;
+}
+#endif /* CONFIG_PNFS_SCSI_LAYOUT */
 
 static int
 bl_parse_slice(struct nfs_server *server, struct pnfs_block_dev *d,
-- 
2.55.0