exofs: Move all operations to an io_engine

In anticipation for multi-device operations, we separate osd operations
into an abstract I/O API. Currently only one device is used but later
when adding more devices, we will drive all devices in parallel according
to a "data_map" that describes how data is arranged on multiple devices.
The file system level operates, like before, as if there is one object
(inode-number) and an i_size. The io engine will split this to the same
object-number but on multiple device.

At first we introduce Mirror (raid 1) layout. But at the final outcome
we intend to fully implement the pNFS-Objects data-map, including
raid 0,4,5,6 over mirrored devices, over multiple device-groups. And
more. See: http://tools.ietf.org/html/draft-ietf-nfsv4-pnfs-obj-12

* Define an io_state based API for accessing osd storage devices
  in an abstract way.
  Usage:
	First a caller allocates an io state with:
		exofs_get_io_state(struct exofs_sb_info *sbi,
				   struct exofs_io_state** ios);

	Then calles one of:
		exofs_sbi_create(struct exofs_io_state *ios);
		exofs_sbi_remove(struct exofs_io_state *ios);
		exofs_sbi_write(struct exofs_io_state *ios);
		exofs_sbi_read(struct exofs_io_state *ios);
		exofs_oi_truncate(struct exofs_i_info *oi, u64 new_len);

	And when done
		exofs_put_io_state(struct exofs_io_state *ios);

* Convert all source files to use this new API
* Convert from bio_alloc to bio_kmalloc
* In io engine we make use of the now fixed osd_req_decode_sense

There are no functional changes or on disk additions after this patch.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>

fs/exofs/common.h

@@ -155,22 +155,4 @@ enum {
 	(((name_len) + offsetof(struct exofs_dir_entry, name)  + \
 	  EXOFS_DIR_ROUND) & ~EXOFS_DIR_ROUND)
 
-/*************************
- * function declarations *
- *************************/
-/* osd.c                 */
-void exofs_make_credential(u8 cred_a[OSD_CAP_LEN],
-			   const struct osd_obj_id *obj);
-
-int exofs_check_ok_resid(struct osd_request *or, u64 *in_resid, u64 *out_resid);
-static inline int exofs_check_ok(struct osd_request *or)
-{
-	return exofs_check_ok_resid(or, NULL, NULL);
-}
-int exofs_sync_op(struct osd_request *or, int timeout, u8 *cred);
-int exofs_async_op(struct osd_request *or,
-	osd_req_done_fn *async_done, void *caller_context, u8 *cred);
-
-int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr);
-
 #endif /*ifndef __EXOFS_COM_H__*/

fs/exofs/exofs.h

@@ -30,14 +30,13 @@
  * along with exofs; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
+#ifndef __EXOFS_H__
+#define __EXOFS_H__
 
 #include <linux/fs.h>
 #include <linux/time.h>
 #include "common.h"
 
-#ifndef __EXOFS_H__
-#define __EXOFS_H__
-
 #define EXOFS_ERR(fmt, a...) printk(KERN_ERR "exofs: " fmt, ##a)
 
 #ifdef CONFIG_EXOFS_DEBUG
@@ -56,6 +55,7 @@
  */
 struct exofs_sb_info {
 	struct osd_dev	*s_dev;			/* returned by get_osd_dev    */
+	struct exofs_fscb s_fscb;		/* Written often, pre-allocate*/
 	osd_id		s_pid;			/* partition ID of file system*/
 	int		s_timeout;		/* timeout for OSD operations */
 	uint64_t	s_nextid;		/* highest object ID used     */
@@ -79,6 +79,50 @@ struct exofs_i_info {
 	struct inode   vfs_inode;          /* normal in-memory inode          */
 };
 
+static inline osd_id exofs_oi_objno(struct exofs_i_info *oi)
+{
+	return oi->vfs_inode.i_ino + EXOFS_OBJ_OFF;
+}
+
+struct exofs_io_state;
+typedef void (*exofs_io_done_fn)(struct exofs_io_state *or, void *private);
+
+struct exofs_io_state {
+	struct kref		kref;
+
+	void			*private;
+	exofs_io_done_fn	done;
+
+	struct exofs_sb_info	*sbi;
+	struct osd_obj_id	obj;
+	u8			*cred;
+
+	/* Global read/write IO*/
+	loff_t			offset;
+	unsigned long		length;
+	void			*kern_buff;
+	struct bio		*bio;
+
+	/* Attributes */
+	unsigned		in_attr_len;
+	struct osd_attr 	*in_attr;
+	unsigned		out_attr_len;
+	struct osd_attr 	*out_attr;
+
+	/* Variable array of size numdevs */
+	unsigned numdevs;
+	struct exofs_per_dev_state {
+		struct osd_request *or;
+		struct bio *bio;
+	} per_dev[];
+};
+
+static inline unsigned exofs_io_state_size(unsigned numdevs)
+{
+	return sizeof(struct exofs_io_state) +
+		sizeof(struct exofs_per_dev_state) * numdevs;
+}
+
 /*
  * our inode flags
  */
@@ -130,6 +174,42 @@ static inline struct exofs_i_info *exofs_i(struct inode *inode)
 /*************************
  * function declarations *
  *************************/
+
+/* ios.c */
+void exofs_make_credential(u8 cred_a[OSD_CAP_LEN],
+			   const struct osd_obj_id *obj);
+int exofs_read_kern(struct osd_dev *od, u8 *cred, struct osd_obj_id *obj,
+		    u64 offset, void *p, unsigned length);
+
+int  exofs_get_io_state(struct exofs_sb_info *sbi, struct exofs_io_state** ios);
+void exofs_put_io_state(struct exofs_io_state *ios);
+
+int exofs_check_io(struct exofs_io_state *ios, u64 *resid);
+
+int exofs_sbi_create(struct exofs_io_state *ios);
+int exofs_sbi_remove(struct exofs_io_state *ios);
+int exofs_sbi_write(struct exofs_io_state *ios);
+int exofs_sbi_read(struct exofs_io_state *ios);
+
+int extract_attr_from_ios(struct exofs_io_state *ios, struct osd_attr *attr);
+
+int exofs_oi_truncate(struct exofs_i_info *oi, u64 new_len);
+static inline int exofs_oi_write(struct exofs_i_info *oi,
+				 struct exofs_io_state *ios)
+{
+	ios->obj.id = exofs_oi_objno(oi);
+	ios->cred = oi->i_cred;
+	return exofs_sbi_write(ios);
+}
+
+static inline int exofs_oi_read(struct exofs_i_info *oi,
+				struct exofs_io_state *ios)
+{
+	ios->obj.id = exofs_oi_objno(oi);
+	ios->cred = oi->i_cred;
+	return exofs_sbi_read(ios);
+}
+
 /* inode.c               */
 void exofs_truncate(struct inode *inode);
 int exofs_setattr(struct dentry *, struct iattr *);
@@ -169,6 +249,7 @@ extern const struct file_operations exofs_file_operations;
 
 /* inode.c           */
 extern const struct address_space_operations exofs_aops;
+extern const struct osd_attr g_attr_logical_length;
 
 /* namei.c           */
 extern const struct inode_operations exofs_dir_inode_operations;