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: NBoaz 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;

fs/exofs/ios.c

@@ -23,88 +23,327 @@
  */
 
 #include <scsi/scsi_device.h>
-#include <scsi/osd_sense.h>
 
 #include "exofs.h"
 
-int exofs_check_ok_resid(struct osd_request *or, u64 *in_resid, u64 *out_resid)
+void exofs_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj)
 {
-	struct osd_sense_info osi;
-	int ret = osd_req_decode_sense(or, &osi);
-
-	if (ret) { /* translate to Linux codes */
-		if (osi.additional_code == scsi_invalid_field_in_cdb) {
-			if (osi.cdb_field_offset == OSD_CFO_STARTING_BYTE)
-				ret = -EFAULT;
-			if (osi.cdb_field_offset == OSD_CFO_OBJECT_ID)
-				ret = -ENOENT;
-			else
-				ret = -EINVAL;
-		} else if (osi.additional_code == osd_quota_error)
-			ret = -ENOSPC;
-		else
-			ret = -EIO;
+	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
+}
+
+int exofs_read_kern(struct osd_dev *od, u8 *cred, struct osd_obj_id *obj,
+		    u64 offset, void *p, unsigned length)
+{
+	struct osd_request *or = osd_start_request(od, GFP_KERNEL);
+/*	struct osd_sense_info osi = {.key = 0};*/
+	int ret;
+
+	if (unlikely(!or)) {
+		EXOFS_DBGMSG("%s: osd_start_request failed.\n", __func__);
+		return -ENOMEM;
+	}
+	ret = osd_req_read_kern(or, obj, offset, p, length);
+	if (unlikely(ret)) {
+		EXOFS_DBGMSG("%s: osd_req_read_kern failed.\n", __func__);
+		goto out;
 	}
 
-	/* FIXME: should be include in osd_sense_info */
-	if (in_resid)
-		*in_resid = or->in.req ? or->in.req->resid_len : 0;
+	ret = osd_finalize_request(or, 0, cred, NULL);
+	if (unlikely(ret)) {
+		EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n", ret);
+		goto out;
+	}
 
-	if (out_resid)
-		*out_resid = or->out.req ? or->out.req->resid_len : 0;
+	ret = osd_execute_request(or);
+	if (unlikely(ret))
+		EXOFS_DBGMSG("osd_execute_request() => %d\n", ret);
+	/* osd_req_decode_sense(or, ret); */
 
+out:
+	osd_end_request(or);
 	return ret;
 }
 
-void exofs_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj)
+int exofs_get_io_state(struct exofs_sb_info *sbi, struct exofs_io_state** pios)
 {
-	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
-}
+	struct exofs_io_state *ios;
 
-/*
- * Perform a synchronous OSD operation.
+	/*TODO: Maybe use kmem_cach per sbi of size
+	 * exofs_io_state_size(sbi->s_numdevs)
 	 */
-int exofs_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
+	ios = kzalloc(exofs_io_state_size(1), GFP_KERNEL);
+	if (unlikely(!ios)) {
+		*pios = NULL;
+		return -ENOMEM;
+	}
+
+	ios->sbi = sbi;
+	ios->obj.partition = sbi->s_pid;
+	*pios = ios;
+	return 0;
+}
+
+void exofs_put_io_state(struct exofs_io_state *ios)
 {
-	int ret;
+	if (ios) {
+		unsigned i;
 
-	or->timeout = timeout;
-	ret = osd_finalize_request(or, 0, credential, NULL);
-	if (ret) {
-		EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n", ret);
+		for (i = 0; i < ios->numdevs; i++) {
+			struct exofs_per_dev_state *per_dev = &ios->per_dev[i];
+
+			if (per_dev->or)
+				osd_end_request(per_dev->or);
+			if (per_dev->bio)
+				bio_put(per_dev->bio);
+		}
+
+		kfree(ios);
+	}
+}
+
+static void _sync_done(struct exofs_io_state *ios, void *p)
+{
+	struct completion *waiting = p;
+
+	complete(waiting);
+}
+
+static void _last_io(struct kref *kref)
+{
+	struct exofs_io_state *ios = container_of(
+					kref, struct exofs_io_state, kref);
+
+	ios->done(ios, ios->private);
+}
+
+static void _done_io(struct osd_request *or, void *p)
+{
+	struct exofs_io_state *ios = p;
+
+	kref_put(&ios->kref, _last_io);
+}
+
+static int exofs_io_execute(struct exofs_io_state *ios)
+{
+	DECLARE_COMPLETION_ONSTACK(wait);
+	bool sync = (ios->done == NULL);
+	int i, ret;
+
+	if (sync) {
+		ios->done = _sync_done;
+		ios->private = &wait;
+	}
+
+	for (i = 0; i < ios->numdevs; i++) {
+		struct osd_request *or = ios->per_dev[i].or;
+		if (unlikely(!or))
+			continue;
+
+		ret = osd_finalize_request(or, 0, ios->cred, NULL);
+		if (unlikely(ret)) {
+			EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n",
+				     ret);
 			return ret;
 		}
+	}
 
-	ret = osd_execute_request(or);
+	kref_init(&ios->kref);
 
-	if (ret)
-		EXOFS_DBGMSG("osd_execute_request() => %d\n", ret);
-	/* osd_req_decode_sense(or, ret); */
+	for (i = 0; i < ios->numdevs; i++) {
+		struct osd_request *or = ios->per_dev[i].or;
+		if (unlikely(!or))
+			continue;
+
+		kref_get(&ios->kref);
+		osd_execute_request_async(or, _done_io, ios);
+	}
+
+	kref_put(&ios->kref, _last_io);
+	ret = 0;
+
+	if (sync) {
+		wait_for_completion(&wait);
+		ret = exofs_check_io(ios, NULL);
+	}
 	return ret;
 }
 
-/*
- * Perform an asynchronous OSD operation.
+int exofs_check_io(struct exofs_io_state *ios, u64 *resid)
+{
+	enum osd_err_priority acumulated_osd_err = 0;
+	int acumulated_lin_err = 0;
+	int i;
+
+	for (i = 0; i < ios->numdevs; i++) {
+		struct osd_sense_info osi;
+		int ret = osd_req_decode_sense(ios->per_dev[i].or, &osi);
+
+		if (likely(!ret))
+			continue;
+
+		if (unlikely(ret == -EFAULT)) {
+			EXOFS_DBGMSG("%s: EFAULT Need page clear\n", __func__);
+			/*FIXME: All the pages in this device range should:
+			 *	clear_highpage(page);
 			 */
-int exofs_async_op(struct osd_request *or, osd_req_done_fn *async_done,
-		   void *caller_context, u8 *cred)
+		}
+
+		if (osi.osd_err_pri >= acumulated_osd_err) {
+			acumulated_osd_err = osi.osd_err_pri;
+			acumulated_lin_err = ret;
+		}
+	}
+
+	/* TODO: raid specific residual calculations */
+	if (resid) {
+		if (likely(!acumulated_lin_err))
+			*resid = 0;
+		else
+			*resid = ios->length;
+	}
+
+	return acumulated_lin_err;
+}
+
+int exofs_sbi_create(struct exofs_io_state *ios)
 {
-	int ret;
+	int i, ret;
 
-	ret = osd_finalize_request(or, 0, cred, NULL);
-	if (ret) {
-		EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n", ret);
+	for (i = 0; i < 1; i++) {
+		struct osd_request *or;
+
+		or = osd_start_request(ios->sbi->s_dev, GFP_KERNEL);
+		if (unlikely(!or)) {
+			EXOFS_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		ios->per_dev[i].or = or;
+		ios->numdevs++;
+
+		osd_req_create_object(or, &ios->obj);
+	}
+	ret = exofs_io_execute(ios);
+
+out:
 	return ret;
+}
+
+int exofs_sbi_remove(struct exofs_io_state *ios)
+{
+	int i, ret;
+
+	for (i = 0; i < 1; i++) {
+		struct osd_request *or;
+
+		or = osd_start_request(ios->sbi->s_dev, GFP_KERNEL);
+		if (unlikely(!or)) {
+			EXOFS_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
 		}
+		ios->per_dev[i].or = or;
+		ios->numdevs++;
 
-	ret = osd_execute_request_async(or, async_done, caller_context);
+		osd_req_remove_object(or, &ios->obj);
+	}
+	ret = exofs_io_execute(ios);
 
-	if (ret)
-		EXOFS_DBGMSG("osd_execute_request_async() => %d\n", ret);
+out:
 	return ret;
 }
 
-int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
+int exofs_sbi_write(struct exofs_io_state *ios)
+{
+	int i, ret;
+
+	for (i = 0; i < 1; i++) {
+		struct osd_request *or;
+
+		or = osd_start_request(ios->sbi->s_dev, GFP_KERNEL);
+		if (unlikely(!or)) {
+			EXOFS_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		ios->per_dev[i].or = or;
+		ios->numdevs++;
+
+		if (ios->bio) {
+			struct bio *bio;
+
+			bio = ios->bio;
+
+			osd_req_write(or, &ios->obj, ios->offset, bio,
+				      ios->length);
+/*			EXOFS_DBGMSG("write sync=%d\n", sync);*/
+		} else if (ios->kern_buff) {
+			osd_req_write_kern(or, &ios->obj, ios->offset,
+					   ios->kern_buff, ios->length);
+/*			EXOFS_DBGMSG("write_kern sync=%d\n", sync);*/
+		} else {
+			osd_req_set_attributes(or, &ios->obj);
+/*			EXOFS_DBGMSG("set_attributes sync=%d\n", sync);*/
+		}
+
+		if (ios->out_attr)
+			osd_req_add_set_attr_list(or, ios->out_attr,
+						  ios->out_attr_len);
+
+		if (ios->in_attr)
+			osd_req_add_get_attr_list(or, ios->in_attr,
+						  ios->in_attr_len);
+	}
+	ret = exofs_io_execute(ios);
+
+out:
+	return ret;
+}
+
+int exofs_sbi_read(struct exofs_io_state *ios)
+{
+	int i, ret;
+
+	for (i = 0; i < 1; i++) {
+		struct osd_request *or;
+
+		or = osd_start_request(ios->sbi->s_dev, GFP_KERNEL);
+		if (unlikely(!or)) {
+			EXOFS_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		ios->per_dev[i].or = or;
+		ios->numdevs++;
+
+		if (ios->bio) {
+			osd_req_read(or, &ios->obj, ios->offset, ios->bio,
+				     ios->length);
+/*			EXOFS_DBGMSG("read sync=%d\n", sync);*/
+		} else if (ios->kern_buff) {
+			osd_req_read_kern(or, &ios->obj, ios->offset,
+					   ios->kern_buff, ios->length);
+/*			EXOFS_DBGMSG("read_kern sync=%d\n", sync);*/
+		} else {
+			osd_req_get_attributes(or, &ios->obj);
+/*			EXOFS_DBGMSG("get_attributes sync=%d\n", sync);*/
+		}
+
+		if (ios->out_attr)
+			osd_req_add_set_attr_list(or, ios->out_attr,
+						  ios->out_attr_len);
+
+		if (ios->in_attr)
+			osd_req_add_get_attr_list(or, ios->in_attr,
+						  ios->in_attr_len);
+	}
+	ret = exofs_io_execute(ios);
+
+out:
+	return ret;
+}
+
+int extract_attr_from_ios(struct exofs_io_state *ios, struct osd_attr *attr)
 {
 	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
 	void *iter = NULL;
@@ -112,7 +351,8 @@ int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
 
 	do {
 		nelem = 1;
-		osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter);
+		osd_req_decode_get_attr_list(ios->per_dev[0].or,
+					     &cur_attr, &nelem, &iter);
 		if ((cur_attr.attr_page == attr->attr_page) &&
 		    (cur_attr.attr_id == attr->attr_id)) {
 			attr->len = cur_attr.len;
@@ -123,3 +363,43 @@ int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
 
 	return -EIO;
 }
+
+int exofs_oi_truncate(struct exofs_i_info *oi, u64 size)
+{
+	struct exofs_sb_info *sbi = oi->vfs_inode.i_sb->s_fs_info;
+	struct exofs_io_state *ios;
+	struct osd_attr attr;
+	__be64 newsize;
+	int i, ret;
+
+	if (exofs_get_io_state(sbi, &ios))
+		return -ENOMEM;
+
+	ios->obj.id = exofs_oi_objno(oi);
+	ios->cred = oi->i_cred;
+
+	newsize = cpu_to_be64(size);
+	attr = g_attr_logical_length;
+	attr.val_ptr = &newsize;
+
+	for (i = 0; i < 1; i++) {
+		struct osd_request *or;
+
+		or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+		if (unlikely(!or)) {
+			EXOFS_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		ios->per_dev[i].or = or;
+		ios->numdevs++;
+
+		osd_req_set_attributes(or, &ios->obj);
+		osd_req_add_set_attr_list(or, &attr, 1);
+	}
+	ret = exofs_io_execute(ios);
+
+out:
+	exofs_put_io_state(ios);
+	return ret;
+}

fs/exofs/super.c

@@ -203,49 +203,40 @@ int exofs_sync_fs(struct super_block *sb, int wait)
 {
 	struct exofs_sb_info *sbi;
 	struct exofs_fscb *fscb;
-	struct osd_request *or;
-	struct osd_obj_id obj;
+	struct exofs_io_state *ios;
 	int ret = -ENOMEM;
 
-	fscb = kzalloc(sizeof(struct exofs_fscb), GFP_KERNEL);
-	if (!fscb) {
-		EXOFS_ERR("exofs_write_super: memory allocation failed.\n");
-		return -ENOMEM;
-	}
-
 	lock_super(sb);
 	sbi = sb->s_fs_info;
+	fscb = &sbi->s_fscb;
+
+	ret = exofs_get_io_state(sbi, &ios);
+	if (ret)
+		goto out;
+
+	ios->length = sizeof(*fscb);
+	memset(fscb, 0, ios->length);
 	fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
 	fscb->s_numfiles = cpu_to_le32(sbi->s_numfiles);
 	fscb->s_magic = cpu_to_le16(sb->s_magic);
 	fscb->s_newfs = 0;
 
-	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
-	if (unlikely(!or)) {
-		EXOFS_ERR("exofs_write_super: osd_start_request failed.\n");
-		goto out;
-	}
+	ios->obj.id = EXOFS_SUPER_ID;
+	ios->offset = 0;
+	ios->kern_buff = fscb;
+	ios->cred = sbi->s_cred;
 
-	obj.partition = sbi->s_pid;
-	obj.id = EXOFS_SUPER_ID;
-	ret = osd_req_write_kern(or, &obj, 0, fscb, sizeof(*fscb));
-	if (unlikely(ret)) {
-		EXOFS_ERR("exofs_write_super: osd_req_write_kern failed.\n");
-		goto out;
-	}
-
-	ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
+	ret = exofs_sbi_write(ios);
 	if (unlikely(ret)) {
-		EXOFS_ERR("exofs_write_super: exofs_sync_op failed.\n");
+		EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
 		goto out;
 	}
 	sb->s_dirt = 0;
 
 out:
-	if (or)
-		osd_end_request(or);
+	EXOFS_DBGMSG("s_nextid=0x%llx ret=%d\n", _LLU(sbi->s_nextid), ret);
+	exofs_put_io_state(ios);
 	unlock_super(sb);
-	kfree(fscb);
 	return ret;
 }
 
@@ -302,24 +293,23 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	struct inode *root;
 	struct exofs_mountopt *opts = data;
 	struct exofs_sb_info *sbi;	/*extended info                  */
+	struct osd_dev *od;		/* Master device                 */
 	struct exofs_fscb fscb;		/*on-disk superblock info        */
-	struct osd_request *or = NULL;
 	struct osd_obj_id obj;
 	int ret;
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
 		return -ENOMEM;
-	sb->s_fs_info = sbi;
 
 	/* use mount options to fill superblock */
-	sbi->s_dev = osduld_path_lookup(opts->dev_name);
-	if (IS_ERR(sbi->s_dev)) {
-		ret = PTR_ERR(sbi->s_dev);
-		sbi->s_dev = NULL;
+	od = osduld_path_lookup(opts->dev_name);
+	if (IS_ERR(od)) {
+		ret = PTR_ERR(od);
 		goto free_sbi;
 	}
 
+	sbi->s_dev = od;
 	sbi->s_pid = opts->pid;
 	sbi->s_timeout = opts->timeout;
 
@@ -333,35 +323,13 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_bdev = NULL;
 	sb->s_dev = 0;
 
-	/* read data from on-disk superblock object */
 	obj.partition = sbi->s_pid;
 	obj.id = EXOFS_SUPER_ID;
 	exofs_make_credential(sbi->s_cred, &obj);
 
-	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
-	if (unlikely(!or)) {
-		if (!silent)
-			EXOFS_ERR(
-			       "exofs_fill_super: osd_start_request failed.\n");
-		ret = -ENOMEM;
-		goto free_sbi;
-	}
-	ret = osd_req_read_kern(or, &obj, 0, &fscb, sizeof(fscb));
-	if (unlikely(ret)) {
-		if (!silent)
-			EXOFS_ERR(
-			       "exofs_fill_super: osd_req_read_kern failed.\n");
-		ret = -ENOMEM;
-		goto free_sbi;
-	}
-
-	ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
-	if (unlikely(ret)) {
-		if (!silent)
-			EXOFS_ERR("exofs_fill_super: exofs_sync_op failed.\n");
-		ret = -EIO;
+	ret = exofs_read_kern(od, sbi->s_cred, &obj, 0, &fscb, sizeof(fscb));
+	if (unlikely(ret))
 		goto free_sbi;
-	}
 
 	sb->s_magic = le16_to_cpu(fscb.s_magic);
 	sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
@@ -380,6 +348,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	spin_lock_init(&sbi->s_next_gen_lock);
 
 	/* set up operation vectors */
+	sb->s_fs_info = sbi;
 	sb->s_op = &exofs_sops;
 	sb->s_export_op = &exofs_export_ops;
 	root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
@@ -406,16 +375,14 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	_exofs_print_device("Mounting", opts->dev_name, sbi->s_dev, sbi->s_pid);
-	ret = 0;
-out:
-	if (or)
-		osd_end_request(or);
-	return ret;
+	return 0;
 
 free_sbi:
+	EXOFS_ERR("Unable to mount exofs on %s pid=0x%llx err=%d\n",
+		  opts->dev_name, sbi->s_pid, ret);
 	osduld_put_device(sbi->s_dev); /* NULL safe */
 	kfree(sbi);
-	goto out;
+	return ret;
 }
 
 /*
@@ -444,7 +411,7 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct super_block *sb = dentry->d_sb;
 	struct exofs_sb_info *sbi = sb->s_fs_info;
-	struct osd_obj_id obj = {sbi->s_pid, 0};
+	struct exofs_io_state *ios;
 	struct osd_attr attrs[] = {
 		ATTR_DEF(OSD_APAGE_PARTITION_QUOTAS,
 			OSD_ATTR_PQ_CAPACITY_QUOTA, sizeof(__be64)),
@@ -453,26 +420,25 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	};
 	uint64_t capacity = ULLONG_MAX;
 	uint64_t used = ULLONG_MAX;
-	struct osd_request *or;
 	uint8_t cred_a[OSD_CAP_LEN];
 	int ret;
 
-	/* get used/capacity attributes */
-	exofs_make_credential(cred_a, &obj);
-
-	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
-	if (unlikely(!or)) {
-		EXOFS_DBGMSG("exofs_statfs: osd_start_request failed.\n");
-		return -ENOMEM;
+	ret = exofs_get_io_state(sbi, &ios);
+	if (ret) {
+		EXOFS_DBGMSG("exofs_get_io_state failed.\n");
+		return ret;
 	}
 
-	osd_req_get_attributes(or, &obj);
-	osd_req_add_get_attr_list(or, attrs, ARRAY_SIZE(attrs));
-	ret = exofs_sync_op(or, sbi->s_timeout, cred_a);
+	exofs_make_credential(cred_a, &ios->obj);
+	ios->cred = sbi->s_cred;
+	ios->in_attr = attrs;
+	ios->in_attr_len = ARRAY_SIZE(attrs);
+
+	ret = exofs_sbi_read(ios);
 	if (unlikely(ret))
 		goto out;
 
-	ret = extract_attr_from_req(or, &attrs[0]);
+	ret = extract_attr_from_ios(ios, &attrs[0]);
 	if (likely(!ret)) {
 		capacity = get_unaligned_be64(attrs[0].val_ptr);
 		if (unlikely(!capacity))
@@ -480,7 +446,7 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	} else
 		EXOFS_DBGMSG("exofs_statfs: get capacity failed.\n");
 
-	ret = extract_attr_from_req(or, &attrs[1]);
+	ret = extract_attr_from_ios(ios, &attrs[1]);
 	if (likely(!ret))
 		used = get_unaligned_be64(attrs[1].val_ptr);
 	else
@@ -497,7 +463,7 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_namelen = EXOFS_NAME_LEN;
 
 out:
-	osd_end_request(or);
+	exofs_put_io_state(ios);
 	return ret;
 }