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>

1 files changed, 84 insertions, 3 deletions

diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
index 5ec72e020b22..2e08859a89e8 100644
--- a/fs/exofs/exofs.h
+++ b/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;