pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing

This patches moves parsing of the GETDEVICEINFO XDR to kernel space, as well
as the management of complex devices.  The reason for that is we might have
multiple outstanding complex devices after a NOTIFY_DEVICEID4_CHANGE, which
device mapper or md can't handle as they claim devices exclusively.

But as is turns out simple striping / concatenation is fairly trivial to
implement anyway, so we make our life simpler by reducing the reliance
on blkmapd.  For now we still use blkmapd by feeding it synthetic SIMPLE
device XDR to translate device signatures to device numbers, but in the
long runs I have plans to eliminate it entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 77 insertions, 6 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h
index c98d98a..92dca9e 100644
--- a/fs/nfs/blocklayout/blocklayout.h
+++ b/fs/nfs/blocklayout/blocklayout.h
@@ -44,9 +44,77 @@
 #define PAGE_CACHE_SECTOR_SHIFT (PAGE_CACHE_SHIFT - SECTOR_SHIFT)
 #define SECTOR_SIZE (1 << SECTOR_SHIFT)
 
+struct pnfs_block_dev;
+
+enum pnfs_block_volume_type {
+	PNFS_BLOCK_VOLUME_SIMPLE	= 0,
+	PNFS_BLOCK_VOLUME_SLICE		= 1,
+	PNFS_BLOCK_VOLUME_CONCAT	= 2,
+	PNFS_BLOCK_VOLUME_STRIPE	= 3,
+};
+
+#define PNFS_BLOCK_MAX_UUIDS	4
+#define PNFS_BLOCK_MAX_DEVICES	64
+
+/*
+ * Random upper cap for the uuid length to avoid unbounded allocation.
+ * Not actually limited by the protocol.
+ */
+#define PNFS_BLOCK_UUID_LEN	128
+
+
+struct pnfs_block_volume {
+	enum pnfs_block_volume_type	type;
+	union {
+		struct {
+			int		len;
+			int		nr_sigs;
+			struct {
+				u64		offset;
+				u32		sig_len;
+				u8		sig[PNFS_BLOCK_UUID_LEN];
+			} sigs[PNFS_BLOCK_MAX_UUIDS];
+		} simple;
+		struct {
+			u64		start;
+			u64		len;
+			u32		volume;
+		} slice;
+		struct {
+			u32		volumes_count;
+			u32		volumes[PNFS_BLOCK_MAX_DEVICES];
+		} concat;
+		struct {
+			u64		chunk_size;
+			u32		volumes_count;
+			u32		volumes[PNFS_BLOCK_MAX_DEVICES];
+		} stripe;
+	};
+};
+
+struct pnfs_block_dev_map {
+	sector_t			start;
+	sector_t			len;
+
+	sector_t			disk_offset;
+	struct block_device		*bdev;
+};
+
 struct pnfs_block_dev {
-	struct nfs4_deviceid_node	d_node;
-	struct block_device		*d_bdev;
+	struct nfs4_deviceid_node	node;
+
+	u64				start;
+	u64				len;
+
+	u32				nr_children;
+	struct pnfs_block_dev		*children;
+	u64				chunk_size;
+
+	struct block_device		*bdev;
+	u64				disk_offset;
+
+	bool (*map)(struct pnfs_block_dev *dev, u64 offset,
+			struct pnfs_block_dev_map *map);
 };
 
 enum exstate4 {
@@ -110,6 +178,11 @@ struct bl_msg_hdr {
 #define BL_DEVICE_REQUEST_PROC         0x1 /* User level process succeeds */
 #define BL_DEVICE_REQUEST_ERR          0x2 /* User level process fails */
 
+/* dev.c */
+struct nfs4_deviceid_node *bl_alloc_deviceid_node(struct nfs_server *server,
+		struct pnfs_device *pdev, gfp_t gfp_mask);
+void bl_free_deviceid_node(struct nfs4_deviceid_node *d);
+
 /* extent_tree.c */
 int ext_tree_insert(struct pnfs_block_layout *bl,
 		struct pnfs_block_extent *new);
@@ -123,10 +196,8 @@ int ext_tree_prepare_commit(struct nfs4_layoutcommit_args *arg);
 void ext_tree_mark_committed(struct nfs4_layoutcommit_args *arg, int status);
 
 /* rpc_pipefs.c */
-struct nfs4_deviceid_node *bl_alloc_deviceid_node(struct nfs_server *server,
-		struct pnfs_device *pdev, gfp_t gfp_mask);
-void bl_free_deviceid_node(struct nfs4_deviceid_node *d);
-
+dev_t bl_resolve_deviceid(struct nfs_server *server,
+		struct pnfs_block_volume *b, gfp_t gfp_mask);
 int __init bl_init_pipefs(void);
 void __exit bl_cleanup_pipefs(void);