osdblk: a Linux block device for OSD objects

As I promised in older exofs threads, here is a client for libosd _other_ than exofs. This block driver exports a single OSD object as a Linux block device.

As I promised in older exofs threads, here is a client for libosd _other_ than exofs. This block driver exports a single OSD object as a Linux block device.

See the comment block at the top of the driver for usage instructions.

 drivers/block/Kconfig  |   16 +
 drivers/block/Makefile |    1 
 drivers/block/osdblk.c |  563 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 580 insertions(+)

It should be noted that the first handful of functions are duplicates of fs/exofs/osd.c; an obvious consolidation is in order.

drivers/block/Kconfig +16 -0

index e7b8aa0..ff46b0e 100644
@@ -298,6 +298,22 @@ config BLK_DEV_NBD
 
 	  If unsure, say N.
 
+config BLK_DEV_OSD
+	tristate "OSD object-as-blkdev support"
+	depends on SCSI_OSD_INITIATOR
+	---help---
+	  Saying Y or M here will allow the exporting of a single SCSI
+	  OSD (object-based storage) object as a Linux block device.
+
+	  For example, if you create a 2G object on an OSD device,
+	  you can then use this module to present that 2G object as
+	  a Linux block device.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called osdblk.
+
+	  If unsure, say N.
+
 config BLK_DEV_SX8
 	tristate "Promise SATA SX8 support"
 	depends on PCI

drivers/block/Makefile +1 -0

index 3145141..859bf5d 100644
@@ -22,6 +22,7 @@ obj-$(CONFIG_BLK_DEV_DAC960)	+= DAC960.o
 obj-$(CONFIG_XILINX_SYSACE)	+= xsysace.o
 obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
 obj-$(CONFIG_SUNVDC)		+= sunvdc.o
+obj-$(CONFIG_BLK_DEV_OSD)	+= osdblk.o
 
 obj-$(CONFIG_BLK_DEV_UMEM)	+= umem.o
 obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o

drivers/block/osdblk.c new file +180 -0

new file mode 100644
index 0000000..d3a2fb5
@@ -0,0 +1,563 @@
+
+/*
+   osdblk.c -- Export a single SCSI OSD object as a Linux block device
+
+
+   Copyright 2009 Red Hat, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING.  If not, write to
+   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+   Instructions for use
+   --------------------
+
+   1) Map a Linux block device to an existing OSD object.
+
+      In this example, we will use partition id 1234, object id 5678,
+      OSD device /dev/osd1.
+
+      $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add
+
+
+   2) List all active blkdev<->object mappings.
+
+      In this example, we have performed step #1 twice, creating two blkdevs,
+      mapped to two separate OSD objects.
+
+      $ cat /sys/class/osdblk/list
+      0 174 1234 5678 /dev/osd1
+      1 179 1994 897123 /dev/osd0
+
+      The columns, in order, are:
+      - blkdev unique id
+      - blkdev assigned major
+      - OSD object partition id
+      - OSD object id
+      - OSD device
+
+
+   3) Remove an active blkdev<->object mapping.
+
+      $ echo 1 > /sys/class/osdblk/remove
+
+
+   NOTE:  The actual creation and deletion of OSD objects is outside the scope
+   of this driver.
+
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <scsi/osd_initiator.h>
+#include <scsi/osd_attributes.h>
+#include <scsi/osd_sec.h>
+
+#define DRV_NAME "osdblk"
+#define PFX DRV_NAME ": "
+
+struct osdblk_device;
+
+enum {
+	OSDBLK_MAX_DEVS		= 64,
+	OSDBLK_MINORS_PER_MAJOR	= 256,
+	OSDBLK_MAX_REQ		= 32,
+	OSDBLK_OP_TIMEOUT	= 4 * 60,
+};
+
+struct osdblk_request {
+	struct request		*rq;
+	struct bio		*bio;
+	struct osdblk_device	*osdev;
+	int			tag;
+	uint8_t			cred[OSD_CAP_LEN];
+};
+
+struct osdblk_device {
+	int			id;
+
+	int			major;
+	struct gendisk		*disk;
+	struct request_queue	*q;
+
+	struct osd_dev		*osd;
+
+	char			name[32];
+
+	spinlock_t		lock;
+
+	struct osd_obj_id	obj;
+	uint8_t			obj_cred[OSD_CAP_LEN];
+
+	struct osdblk_request	req[OSDBLK_MAX_REQ];
+
+	unsigned long		part_id;
+	unsigned long		obj_id;
+	char			osd_path[0];
+};
+
+static struct class *class_osdblk;		/* /sys/class/osdblk */
+static struct mutex ctl_mutex;	/* Serialize open/close/setup/teardown */
+static struct osdblk_device *osdblk_devs[OSDBLK_MAX_DEVS];
+
+static struct block_device_operations osdblk_bd_ops = {
+	.owner		= THIS_MODULE,
+};
+
+const struct osd_attr g_attr_logical_length = ATTR_DEF(
+	OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
+
+static void osd_make_credential(u8 cred_a[OSD_CAP_LEN],
+				const struct osd_obj_id *obj)
+{
+	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
+}
+
+/*
+ * Perform a synchronous OSD operation.
+ */
+static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
+{
+	int ret;
+
+	or->timeout = timeout;
+	ret = osd_finalize_request(or, 0, credential, NULL);
+	if (ret)
+		return ret;
+
+	ret = osd_execute_request(or);
+
+	/* osd_req_decode_sense(or, ret); */
+	return ret;
+}
+
+/*
+ * Perform an asynchronous OSD operation.
+ */
+static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done,
+		   void *caller_context, u8 *cred)
+{
+	int ret;
+
+	ret = osd_finalize_request(or, 0, cred, NULL);
+	if (ret)
+		return ret;
+
+	ret = osd_execute_request_async(or, async_done, caller_context);
+
+	return ret;
+}
+
+static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
+{
+	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
+	void *iter = NULL;
+	int nelem;
+
+	do {
+		nelem = 1;
+		osd_req_decode_get_attr_list(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;
+			attr->val_ptr = cur_attr.val_ptr;
+			return 0;
+		}
+	} while (iter);
+
+	return -EIO;

drivers/block/osdblk.c new file +56 -0

+	or = osd_start_request(osdev->osd, GFP_KERNEL);
+	if (!or)
+		return -ENOMEM;
+
+	osd_req_get_attributes(or, &osdev->obj);
+
+	osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);
+
+	/* execute op synchronously */
+	ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred);
+	if (ret)
+		goto out;
+
+	attr = g_attr_logical_length;
+	ret = extract_attr_from_req(or, &attr);
+	if (ret)
+		goto out;
+
+	*size_out = get_unaligned_be64(attr.val_ptr);
+
+out:
+	osd_end_request(or);
+	return ret;
+
+}
+
+static int osdblk_get_free_req(struct osdblk_device *osdev)
+{
+	int i;
+
+	for (i = 0; i < OSDBLK_MAX_REQ; i++) {
+		if (!osdev->req[i].rq)
+			return i;
+	}
+
+	return -1;
+}
+
+static void osdblk_end_request(struct osdblk_device *osdev,
+			       struct osdblk_request *orq,
+			       int error)
+{
+	struct request *rq = orq->rq;
+	int rc;
+
+	/* complete request, at block layer */
+	rc = __blk_end_request(rq, error, blk_rq_bytes(rq));
+
+	/* clear request slot for use */
+	osdev->req[orq->tag].rq = NULL;
+
+	/* restart queue, if necessary */
+	blk_start_queue(osdev->q);
+}
+
+static void osdblk_osd_complete(struct osd_request *or, void *private)

drivers/block/osdblk.c new file +28 -0

+}
+
+static void osdblk_rq_fn(struct request_queue *q)
+{
+	struct osdblk_device *osdev = q->queuedata;
+	struct request *rq;
+	struct osdblk_request *orq;
+	struct osd_request *or;
+	struct bio *bio;
+	int rq_idx, do_write;
+
+	while (1) {
+		rq = elv_next_request(q);
+		if (!rq)
+			break;
+
+		do_write = (rq_data_dir(rq) == WRITE);
+
+		bio = bio_clone(rq->bio, GFP_NOIO);
+		if (!bio)
+			break;
+
+		rq_idx = osdblk_get_free_req(osdev);
+		if (rq_idx < 0) {
+			bio_put(bio);
+			blk_stop_queue(q);
+			break;
+		}

drivers/block/osdblk.c new file +7 -0

+
+		or = osd_start_request(osdev->osd, GFP_NOIO);
+		if (!or) {
+			blk_requeue_request(q, rq);
+			bio_put(bio);
+			break;
+		}

drivers/block/osdblk.c new file +16 -0

+			bio_put(bio);
+		}
+	}
+}
+
+static void osdblk_free_disk(struct osdblk_device *osdev)
+{
+	struct gendisk *disk = osdev->disk;
+
+	if (!disk)
+		return;
+
+	if (disk->flags & GENHD_FL_UP)
+		del_gendisk(disk);
+	if (disk->queue)
+		blk_cleanup_queue(disk->queue);

drivers/block/osdblk.c new file +83 -0

+	rc = osdblk_get_obj_size(osdev, &obj_size);
+	if (rc)
+		return rc;
+
+	disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR);
+	if (!disk)
+		return -ENOMEM;
+
+	sprintf(disk->disk_name, DRV_NAME "/%d", osdev->id);
+	disk->major = osdev->major;
+	disk->first_minor = 0;
+	disk->fops = &osdblk_bd_ops;
+	disk->private_data = osdev;
+
+	q = blk_init_queue(osdblk_rq_fn, &osdev->lock);
+	if (!q) {
+		put_disk(disk);
+		return -ENOMEM;
+	}
+
+	disk->queue = q;
+
+	q->queuedata = osdev;
+
+	osdev->disk = disk;
+	osdev->q = q;
+
+	set_capacity(disk, obj_size);
+	add_disk(disk);
+
+	return 0;
+}
+
+/********************************************************************
+  /sys/class/osdblk/
+                     add	map OSD object to blkdev
+                     remove	unmap OSD object
+                     list	show mappings
+ *******************************************************************/
+
+static void class_osdblk_release(struct class *cls)
+{
+	kfree(cls);
+}
+
+static ssize_t class_osdblk_show(struct class *c, char *data)
+{
+	int n = 0;
+	int idx;
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+	for (idx = 0; idx < OSDBLK_MAX_DEVS; idx++) {
+		struct osdblk_device *osdev = osdblk_devs[idx];
+		if (!osdev)
+			continue;
+		n += sprintf(data+n, "%d %d %lu %lu %s\n",
+			osdev->id,
+			osdev->major,
+			osdev->part_id,
+			osdev->obj_id,
+			osdev->osd_path);
+	}
+	mutex_unlock(&ctl_mutex);
+	return n;
+}
+
+static ssize_t class_osdblk_add(struct class *c, const char *buf, size_t count)
+{
+	struct osdblk_device *osdev;
+	ssize_t rc;
+	int idx, irc;
+
+	osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL);
+	if (!osdev)
+		return -ENOMEM;
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	for (idx = 0; idx < OSDBLK_MAX_DEVS; idx++) {
+		if (!osdblk_devs[idx]) {
+			osdblk_devs[idx] = osdev;
+			osdev->id = idx;
+			break;
+		}

drivers/block/osdblk.c new file +115 -0

+
+	sprintf(osdev->name, DRV_NAME "%d", osdev->id);
+	spin_lock_init(&osdev->lock);
+
+	osdev->osd = osduld_path_lookup(osdev->osd_path);
+	if (IS_ERR(osdev->osd)) {
+		rc = PTR_ERR(osdev->osd);
+		goto err_out_slot;
+	}
+
+	irc = register_blkdev(0, osdev->name);
+	if (irc < 0) {
+		rc = irc;
+		goto err_out_osd;
+	}
+
+	osdev->major = irc;
+
+	rc = osdblk_init_disk(osdev);
+	if (rc)
+		goto err_out_blkdev;
+
+	return 0;
+
+err_out_blkdev:
+	unregister_blkdev(osdev->major, osdev->name);
+err_out_osd:
+	osduld_put_device(osdev->osd);
+err_out_slot:
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+	osdblk_devs[osdev->id] = NULL;
+	mutex_unlock(&ctl_mutex);
+err_out:
+	kfree(osdev);
+	return rc;
+}
+
+static ssize_t class_osdblk_remove(struct class *c, const char *buf,
+					size_t count)
+{
+	struct osdblk_device *osdev;
+	int target_id;
+
+	if (sscanf(buf, "%d", &target_id) != 1)
+		return -EINVAL;
+	if (target_id < 0 || target_id >= OSDBLK_MAX_DEVS)
+		return -EINVAL;
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+	osdev = osdblk_devs[target_id];
+	osdblk_devs[target_id] = NULL;
+	mutex_unlock(&ctl_mutex);
+
+	if (!osdev)
+		return -ENOENT;
+
+	osdblk_free_disk(osdev);
+	unregister_blkdev(osdev->major, osdev->name);
+	osduld_put_device(osdev->osd);
+	kfree(osdev);
+
+	return 0;
+}
+
+static struct class_attribute class_osdblk_attrs[] = {
+	__ATTR(add,	0200, NULL, class_osdblk_add),
+	__ATTR(remove,	0200, NULL, class_osdblk_remove),
+	__ATTR(list,	0444, class_osdblk_show, NULL),
+	__ATTR_NULL
+};
+
+static int osdblk_sysfs_init(void)
+{
+	int ret = 0;
+
+	/*
+	 * create control files in sysfs
+	 * /sys/class/osdblk/...
+	 */
+	class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL);
+	if (!class_osdblk)
+		return -ENOMEM;
+
+	class_osdblk->name = DRV_NAME;
+	class_osdblk->owner = THIS_MODULE;
+	class_osdblk->class_release = class_osdblk_release;
+	class_osdblk->class_attrs = class_osdblk_attrs;
+
+	ret = class_register(class_osdblk);
+	if (ret) {
+		kfree(class_osdblk);
+		class_osdblk = NULL;
+		printk(PFX "failed to create class osdblk\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void osdblk_sysfs_cleanup(void)
+{
+	if (class_osdblk)
+		class_destroy(class_osdblk);
+	class_osdblk = NULL;
+}
+
+static int __init osdblk_init(void)
+{
+	int rc;
+
+	rc = osdblk_sysfs_init();
+	if (rc)
+		return rc;
+
+	return 0;

Quoted 4 lines · Jeff Garzik

As I promised in older exofs threads, here is a client for libosd _other_ than exofs. This block driver exports a single OSD object as a Linux block device.

Quoted 9 lines

See the comment block at the top of the driver for usage instructions.

 drivers/block/Kconfig  |   16 +
 drivers/block/Makefile |    1 
 drivers/block/osdblk.c |  563 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 580 insertions(+)

Forwarding to open-osd ml

Jeff is it OK if I pick up this patch through my tree and will push it together with the other pending patches for 2.6.31 Kernel? I intend to

I have taken that to my heart and will submit patches for that, next week. Including a complimentary patch to this driver. These changes are only intended for 2.6.31 though.

I also want to add a small utility that can manage objects, create, size, remove, and mount as a complimentary wrapper for this driver is "osdblk" a good name for such utility?

Quoted 8 lines

drivers/block/osdblk.c new file +8 -0

+static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out)
+{
+	struct osd_request *or;
+	struct osd_attr attr;
+	int ret;
+
+	osd_make_credential(osdev->obj_cred, &osdev->obj);
+

(quoted diff) +0 -1

-	osd_make_credential(osdev->obj_cred, &osdev->obj);

see below

drivers/block/osdblk.c line 256

Quoted 11 lines

drivers/block/osdblk.c new file +11 -0

+static void osdblk_osd_complete(struct osd_request *or, void *private)
+{
+	struct osdblk_request *orq = private;
+	struct osd_sense_info osi;
+	int ret = osd_req_decode_sense(or, &osi);
+
+	if (ret)
+		ret = -EIO;
+
+	osd_end_request(or);
+	osdblk_end_request(orq->osdev, orq, ret);

should be reversed, very bad things will happen otherwise

Quoted 9 lines

drivers/block/osdblk.c new file +9 -0

+		orq = &osdev->req[rq_idx];
+		orq->tag = rq_idx;
+		orq->rq = rq;
+		orq->bio = bio;
+		orq->osdev = osdev;
+
+		blkdev_dequeue_request(rq);
+
+		osd_make_credential(orq->cred, &osdev->obj);

(quoted diff) +0 -1

-		osd_make_credential(orq->cred, &osdev->obj);

Don't do this here do it once on mount. The creds, once we define the credential-manager protocol will have to be acquired at the begging. (See below)

At much later stage, the credential-manager API will be able to callback credentials and clients will need to reacquire them, or on credentials error returns from I/O.

Quoted 7 lines

drivers/block/osdblk.c new file +7 -0

+
+		or = osd_start_request(osdev->osd, GFP_NOIO);
+		if (!or) {
+			blk_requeue_request(q, rq);
+			bio_put(bio);
+			break;
+		}

drivers/block/osdblk.c line 311

Quoted 10 lines

drivers/block/osdblk.c new file +10 -0

+
+		if (do_write)
+			osd_req_write(or, &osdev->obj, bio,
+				      rq->sector * 512ULL);
+		else
+			osd_req_read(or, &osdev->obj, bio,
+				     rq->sector * 512ULL);
+
+		if (osd_async_op(or, osdblk_osd_complete, orq, orq->cred)) {
+			/* FIXME: leak OSD request 'or' ? */

yes a leak

Quoted 1 line

(quoted diff) +1 -0

+			blk_requeue_request(q, rq);

Quoted 26 lines

drivers/block/osdblk.c new file +26 -0

+			bio_put(bio);
+		}
+	}
+}
+
+static void osdblk_free_disk(struct osdblk_device *osdev)
+{
+	struct gendisk *disk = osdev->disk;
+
+	if (!disk)
+		return;
+
+	if (disk->flags & GENHD_FL_UP)
+		del_gendisk(disk);
+	if (disk->queue)
+		blk_cleanup_queue(disk->queue);
+	put_disk(disk);
+}
+
+static int osdblk_init_disk(struct osdblk_device *osdev)
+{
+	struct gendisk *disk;
+	struct request_queue *q;
+	int rc;
+	u64 obj_size = 0;
+

drivers/block/osdblk.c new file +1 -0

+	osd_make_credential(osdev->obj_cred, &osdev->obj);

Later, when credential-manager is used, this will get expensive and sleepy possibly going on the network and back.

Quoted 6 lines

drivers/block/osdblk.c new file +6 -0

+	if (idx == OSDBLK_MAX_DEVS) {
+		rc = -ENOSPC;
+		goto err_out;
+	}
+
+	if (sscanf(buf, "%lu %lu %s", &osdev->part_id, &osdev->obj_id,

(quoted diff) +1 -1

-	if (sscanf(buf, "%lu %lu %s", &osdev->part_id, &osdev->obj_id,
+	if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id,

Quoted 8 lines

drivers/block/osdblk.c new file +7 -0

+		   osdev->osd_path) != 3) {
+		rc = -EINVAL;
+		goto err_out_slot;
+	}
+
+	osdev->obj.partition = osdev->part_id;
+	osdev->obj.id = osdev->obj_id;

(quoted diff) +0 -2

-	osdev->obj.partition = osdev->part_id;
-	osdev->obj.id = osdev->obj_id;

osdev->obj_id, and osdev->part_id can be removed.

What can I say, great stuff.

OSD is a very clean API, that makes whole subsystems look trivial.

Quoted 3 lines · Boaz Harrosh

I have taken that to my heart and will submit patches for that, next week. Including a complimentary patch to this driver. These changes are only intended for 2.6.31 though.

Consolidation of common code should occur after osdblk is in one of:
open-osd.git, scsi-misc.git, or linux-2.6.git.

That way, the code movement can be consolidated into a single changeset, touching exofs, osdblk and libosd all at the same time...
-exofs code
-osdblk code
+libosd code

Quoted 3 lines

I also want to add a small utility that can manage objects, create, size, remove, and mount as a complimentary wrapper for this driver is "osdblk" a good name for such utility?

osdblk intentionally maintains -zero- metadata on its own. Therefore, this utility you propose can be completely generic. You could call it "osdobjutil", because it need not be tied to the osdblk driver.

The osdblk driver needs the following from the utility:

- create object of specified size

- delete object

and optionally:
- resize object to new size

There is no need for a mount operation, because this is handled through class_osdblk_add()

Quoted 13 lines

drivers/block/osdblk.c line 256

Quoted 11 lines

drivers/block/osdblk.c new file +11 -0

+static void osdblk_osd_complete(struct osd_request *or, void *private)
+{
+	struct osdblk_request *orq = private;
+	struct osd_sense_info osi;
+	int ret = osd_req_decode_sense(or, &osi);
+
+	if (ret)
+		ret = -EIO;
+
+	osd_end_request(or);
+	osdblk_end_request(orq->osdev, orq, ret);

should be reversed, very bad things will happen otherwise

Review

Quoted 2 lines

(quoted diff) +2 -0

+	osdblk_end_request(orq->osdev, orq, ret);
+	osd_end_request(or);

Perhaps you are confusing two different 'struct request' in use?

- struct request, passed to osdblk for execution
- struct request, used by libosd to pass commands

The object lifetime of the struct request stored in 'orq' is longer than the lifetime of the osd_request:

1) block layer passes 'rq' to osdblk
2) osdblk creates new 'or', passes 'or' to libosd
3) libosd calls osdblk completion function
4) osdblk completes 'or'
5) osdblk completes 'rq'

As you can see, the object lifetime of 'or' is entirely within 'rq'.

Quoted 5 lines

What can I say, great stuff.

OSD is a very clean API, that makes whole subsystems look trivial.

I appreciate it, thanks for the review.

Jeff

As I promised in older exofs threads, here is a client for libosd _other_ than exofs. This block driver exports a single OSD object as a Linux block device.

See the comment block at the top of the driver for usage instructions.

 drivers/block/Kconfig  |   16 +
 drivers/block/Makefile |    1 
 drivers/block/osdblk.c |  563 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 580 insertions(+)

drivers/block/Kconfig +16 -0

index e7b8aa0..ff46b0e 100644
@@ -298,6 +298,22 @@ config BLK_DEV_NBD
 
 	  If unsure, say N.
 
+config BLK_DEV_OSD
+	tristate "OSD object-as-blkdev support"
+	depends on SCSI_OSD_INITIATOR
+	---help---
+	  Saying Y or M here will allow the exporting of a single SCSI
+	  OSD (object-based storage) object as a Linux block device.
+
+	  For example, if you create a 2G object on an OSD device,
+	  you can then use this module to present that 2G object as
+	  a Linux block device.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called osdblk.
+
+	  If unsure, say N.
+
 config BLK_DEV_SX8
 	tristate "Promise SATA SX8 support"
 	depends on PCI

drivers/block/Makefile +1 -0

index 3145141..859bf5d 100644
@@ -22,6 +22,7 @@ obj-$(CONFIG_BLK_DEV_DAC960)	+= DAC960.o
 obj-$(CONFIG_XILINX_SYSACE)	+= xsysace.o
 obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
 obj-$(CONFIG_SUNVDC)		+= sunvdc.o
+obj-$(CONFIG_BLK_DEV_OSD)	+= osdblk.o
 
 obj-$(CONFIG_BLK_DEV_UMEM)	+= umem.o
 obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o

drivers/block/osdblk.c new file +30 -0

new file mode 100644
index 0000000..d3a2fb5
@@ -0,0 +1,563 @@
+
+/*
+   osdblk.c -- Export a single SCSI OSD object as a Linux block device
+
+
+   Copyright 2009 Red Hat, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING.  If not, write to
+   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+   Instructions for use
+   --------------------
+
+   1) Map a Linux block device to an existing OSD object.
+
+      In this example, we will use partition id 1234, object id 5678,
+      OSD device /dev/osd1.
+
+      $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add

drivers/block/osdblk.c new file +62 -0

+      The columns, in order, are:
+      - blkdev unique id
+      - blkdev assigned major
+      - OSD object partition id
+      - OSD object id
+      - OSD device
+
+
+   3) Remove an active blkdev<->object mapping.
+
+      $ echo 1 > /sys/class/osdblk/remove
+
+
+   NOTE:  The actual creation and deletion of OSD objects is outside the scope
+   of this driver.
+
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <scsi/osd_initiator.h>
+#include <scsi/osd_attributes.h>
+#include <scsi/osd_sec.h>
+
+#define DRV_NAME "osdblk"
+#define PFX DRV_NAME ": "
+
+struct osdblk_device;
+
+enum {
+	OSDBLK_MAX_DEVS		= 64,
+	OSDBLK_MINORS_PER_MAJOR	= 256,
+	OSDBLK_MAX_REQ		= 32,
+	OSDBLK_OP_TIMEOUT	= 4 * 60,
+};
+
+struct osdblk_request {
+	struct request		*rq;
+	struct bio		*bio;
+	struct osdblk_device	*osdev;
+	int			tag;
+	uint8_t			cred[OSD_CAP_LEN];
+};
+
+struct osdblk_device {
+	int			id;
+
+	int			major;
+	struct gendisk		*disk;
+	struct request_queue	*q;
+
+	struct osd_dev		*osd;
+
+	char			name[32];
+
+	spinlock_t		lock;
+
+	struct osd_obj_id	obj;
+	uint8_t			obj_cred[OSD_CAP_LEN];
+

drivers/block/osdblk.c new file +100 -0

+static struct block_device_operations osdblk_bd_ops = {
+	.owner		= THIS_MODULE,
+};
+
+const struct osd_attr g_attr_logical_length = ATTR_DEF(
+	OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
+
+static void osd_make_credential(u8 cred_a[OSD_CAP_LEN],
+				const struct osd_obj_id *obj)
+{
+	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
+}
+
+/*
+ * Perform a synchronous OSD operation.
+ */
+static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
+{
+	int ret;
+
+	or->timeout = timeout;
+	ret = osd_finalize_request(or, 0, credential, NULL);
+	if (ret)
+		return ret;
+
+	ret = osd_execute_request(or);
+
+	/* osd_req_decode_sense(or, ret); */
+	return ret;
+}
+
+/*
+ * Perform an asynchronous OSD operation.
+ */
+static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done,
+		   void *caller_context, u8 *cred)
+{
+	int ret;
+
+	ret = osd_finalize_request(or, 0, cred, NULL);
+	if (ret)
+		return ret;
+
+	ret = osd_execute_request_async(or, async_done, caller_context);
+
+	return ret;
+}
+
+static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
+{
+	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
+	void *iter = NULL;
+	int nelem;
+
+	do {
+		nelem = 1;
+		osd_req_decode_get_attr_list(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;
+			attr->val_ptr = cur_attr.val_ptr;
+			return 0;
+		}
+	} while (iter);
+
+	return -EIO;
+}
+
+static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out)
+{
+	struct osd_request *or;
+	struct osd_attr attr;
+	int ret;
+
+	osd_make_credential(osdev->obj_cred, &osdev->obj);
+
+	or = osd_start_request(osdev->osd, GFP_KERNEL);
+	if (!or)
+		return -ENOMEM;
+
+	osd_req_get_attributes(or, &osdev->obj);
+
+	osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);
+
+	/* execute op synchronously */
+	ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred);
+	if (ret)
+		goto out;
+
+	attr = g_attr_logical_length;
+	ret = extract_attr_from_req(or, &attr);
+	if (ret)
+		goto out;
+
+	*size_out = get_unaligned_be64(attr.val_ptr);
+
+out:
+	osd_end_request(or);
+	return ret;
+

Quoted 12 lines

drivers/block/osdblk.c new file +12 -0

+   1) Map a Linux block device to an existing OSD object.
+
+      In this example, we will use partition id 1234, object id 5678,
+      OSD device /dev/osd1.
+
+      $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add
+
+
+   2) List all active blkdev<->object mappings.
+
+      In this example, we have performed step #1 twice, creating two blkdevs,
+      mapped to two separate OSD objects.

drivers/block/osdblk.c line 40

Quoted 4 lines

drivers/block/osdblk.c new file +4 -0

+
+      $ cat /sys/class/osdblk/list
+      0 174 1234 5678 /dev/osd1
+      1 179 1994 897123 /dev/osd0

This is a slight violation of the one piece of data per sysfs file rule ... might it not be better as a file named <partid>-<objid> linking to the osd device location in sysfs?

Quoted 10 lines

drivers/block/osdblk.c new file +10 -0

+      The columns, in order, are:
+      - blkdev unique id
+      - blkdev assigned major
+      - OSD object partition id
+      - OSD object id
+      - OSD device
+
+
+   3) Remove an active blkdev<->object mapping.
+

drivers/block/osdblk.c line 113

Quoted 7 lines

drivers/block/osdblk.c new file +7 -0

+	unsigned long		obj_id;
+	char			osd_path[0];
+};
+
+static struct class *class_osdblk;		/* /sys/class/osdblk */
+static struct mutex ctl_mutex;	/* Serialize open/close/setup/teardown */
+static struct osdblk_device *osdblk_devs[OSDBLK_MAX_DEVS];

Might it not be better to do this as a linked list on the private dev structure instead? This only works if you have one entry
in /sys/class/osdblock per device because now you have a device private pointer to hang it off

drivers/block/osdblk.c line 224

Quoted 8 lines

drivers/block/osdblk.c new file +8 -0

+static int osdblk_get_free_req(struct osdblk_device *osdev)
+{
+	int i;
+
+	for (i = 0; i < OSDBLK_MAX_REQ; i++) {
+		if (!osdev->req[i].rq)
+			return i;
+	}

Rather than using a static list of outstanding requests, I think you could probably use the block tag handling infrastructure for all of this

As I promised in older exofs threads, here is a client for libosd _other_ than exofs. This block driver exports a single OSD object as a Linux block device.

See the comment block at the top of the driver for usage instructions.

drivers/block/osdblk.c new file +39 -0

+static void osdblk_end_request(struct osdblk_device *osdev,
+			       struct osdblk_request *orq,
+			       int error)
+{
+	struct request *rq = orq->rq;
+	int rc;
+
+	/* complete request, at block layer */
+	rc = __blk_end_request(rq, error, blk_rq_bytes(rq));
+
+	/* clear request slot for use */
+	osdev->req[orq->tag].rq = NULL;
+
+	/* restart queue, if necessary */
+	blk_start_queue(osdev->q);
+}
+
+static void osdblk_osd_complete(struct osd_request *or, void *private)
+{
+	struct osdblk_request *orq = private;
+	struct osd_sense_info osi;
+	int ret = osd_req_decode_sense(or, &osi);
+
+	if (ret)
+		ret = -EIO;
+
+	osd_end_request(or);
+	osdblk_end_request(orq->osdev, orq, ret);
+}
+
+static void osdblk_rq_fn(struct request_queue *q)
+{
+	struct osdblk_device *osdev = q->queuedata;
+	struct request *rq;
+	struct osdblk_request *orq;
+	struct osd_request *or;
+	struct bio *bio;
+	int rq_idx, do_write;
+

This wont work, GFP_NOIO inside the queue lock. You are also only cloning the front bio, what happens if you have > 1 bio on the request? You seem to dequeue the request and complete all of it, regardless of whether bio->bi_size == blk_rq_bytes(rq). I'm assuming you have to clone because of how the osd_req_{read,write} works, so I'd suggest storing the byte size in your osdblk_request and only completing that in osdblk_end_request(). Then do a rq_for_each_bio() look in there, and only dequeue if you manage to start an osd request for each of them, THEN moving on to the next request.

Quoted 9 lines · Jens Axboe

This wont work, GFP_NOIO inside the queue lock. You are also only cloning the front bio, what happens if you have > 1 bio on the request? You seem to dequeue the request and complete all of it, regardless of whether bio->bi_size == blk_rq_bytes(rq). I'm assuming you have to clone because of how the osd_req_{read,write} works, so I'd suggest storing the byte size in your osdblk_request and only completing that in osdblk_end_request(). Then do a rq_for_each_bio() look in there, and only dequeue if you manage to start an osd request for each of them, THEN moving on to the next request.

Thanks for the review. Will fix...

Jeff

Quoted 10 lines · Jeff Garzik

Quoted 9 lines · Jens Axboe

This wont work, GFP_NOIO inside the queue lock. You are also only cloning the front bio, what happens if you have > 1 bio on the request? You seem to dequeue the request and complete all of it, regardless of whether bio->bi_size == blk_rq_bytes(rq). I'm assuming you have to clone because of how the osd_req_{read,write} works, so I'd suggest storing the byte size in your osdblk_request and only completing that in osdblk_end_request(). Then do a rq_for_each_bio() look in there, and only dequeue if you manage to start an osd request for each of them, THEN moving on to the next request.

There is nothing preventing from issuing a linked bio list. The only thing is that osd_read/write looks at the first bio for total size. If the first bio->bi_size does not specify the full length of the chain then we should add another parameter to osd_read/write for that.

The original idea was to specifically allow chained bios.

Please advise?

Quoted 19 lines · Boaz Harrosh

Quoted 10 lines · Jeff Garzik

Quoted 9 lines · Jens Axboe

This wont work, GFP_NOIO inside the queue lock. You are also only cloning the front bio, what happens if you have > 1 bio on the request? You seem to dequeue the request and complete all of it, regardless of whether bio->bi_size == blk_rq_bytes(rq). I'm assuming you have to clone because of how the osd_req_{read,write} works, so I'd suggest storing the byte size in your osdblk_request and only completing that in osdblk_end_request(). Then do a rq_for_each_bio() look in there, and only dequeue if you manage to start an osd request for each of them, THEN moving on to the next request.

There is nothing preventing from issuing a linked bio list. The only thing is that osd_read/write looks at the first bio for total size. If the first bio->bi_size does not specify the full length of the chain then we should add another parameter to osd_read/write for that.

The original idea was to specifically allow chained bios.

Quoted 1 line

Please advise?

As passed to us from the block layer, there is nothing special about the size of the first bio, AFAIK.

This seems like a libosd bug? If you want to support chained bio's, I would presume you would either walk the list and sum all sizes, or in some other way input the total request size?

Quoted 20 lines · Jeff Garzik

Quoted 19 lines · Boaz Harrosh

Quoted 10 lines · Jeff Garzik

Quoted 9 lines · Jens Axboe

This wont work, GFP_NOIO inside the queue lock. You are also only cloning the front bio, what happens if you have > 1 bio on the request? You seem to dequeue the request and complete all of it, regardless of whether bio->bi_size == blk_rq_bytes(rq). I'm assuming you have to clone because of how the osd_req_{read,write} works, so I'd suggest storing the byte size in your osdblk_request and only completing that in osdblk_end_request(). Then do a rq_for_each_bio() look in there, and only dequeue if you manage to start an osd request for each of them, THEN moving on to the next request.

There is nothing preventing from issuing a linked bio list. The only thing is that osd_read/write looks at the first bio for total size. If the first bio->bi_size does not specify the full length of the chain then we should add another parameter to osd_read/write for that.

The original idea was to specifically allow chained bios.

Please advise?

Quoted 3 lines

As passed to us from the block layer, there is nothing special about the size of the first bio, AFAIK.

This seems like a libosd bug? If you want to support chained bio's, I would presume you would either walk the list and sum all sizes, or in some other way input the total request size?

Completely agree, if you want to support passing in a chain, you better make the first bio just part of the chain (not some header bio).

And Jeff, you still have that bio_clone() bug in your v2 posting.

Quoted 28 lines · Jens Axboe

Quoted 26 lines · Jeff Garzik

Quoted 11 lines · Boaz Harrosh

Quoted 10 lines · Jeff Garzik

Quoted 9 lines · Jens Axboe

This wont work, GFP_NOIO inside the queue lock. You are also only cloning the front bio, what happens if you have > 1 bio on the request? You seem to dequeue the request and complete all of it, regardless of whether bio->bi_size == blk_rq_bytes(rq). I'm assuming you have to clone because of how the osd_req_{read,write} works, so I'd suggest storing the byte size in your osdblk_request and only completing that in osdblk_end_request(). Then do a rq_for_each_bio() look in there, and only dequeue if you manage to start an osd request for each of them, THEN moving on to the next request.

Quoted 8 lines

There is nothing preventing from issuing a linked bio list. The only thing is that osd_read/write looks at the first bio for total size. If the first bio->bi_size does not specify the full length of the chain then we should add another parameter to osd_read/write for that.

The original idea was to specifically allow chained bios.

Please advise?

As passed to us from the block layer, there is nothing special about the size of the first bio, AFAIK.

This seems like a libosd bug? If you want to support chained bio's, I would presume you would either walk the list and sum all sizes, or in some other way input the total request size?

Quoted 4 lines

Completely agree, if you want to support passing in a chain, you better make the first bio just part of the chain (not some header bio).

And Jeff, you still have that bio_clone() bug in your v2 posting.

Yep, that was noted in the patch description as "The major remaining pre-merge FIXME" :)

As I promised in older exofs threads, here is a client for libosd _other_ than exofs. This block driver exports a single OSD object as a Linux block device.

See the comment block at the top of the driver for usage instructions.

NOT-Signed-off-by Jeff Garzik <[email protected]>

---
Changes since last version:
- support bio chains

Still needs testing with some real OSD devices...

 drivers/block/Kconfig            |   16 
 drivers/block/Makefile           |    1 
 drivers/block/osdblk.c           |  669 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 754 insertions(+), 16 deletions(-)

drivers/block/Kconfig +16 -0

index ddea8e4..34722c8 100644
@@ -298,6 +298,22 @@ config BLK_DEV_NBD
 
 	  If unsure, say N.
 
+config BLK_DEV_OSD
+	tristate "OSD object-as-blkdev support"
+	depends on SCSI_OSD_INITIATOR
+	---help---
+	  Saying Y or M here will allow the exporting of a single SCSI
+	  OSD (object-based storage) object as a Linux block device.
+
+	  For example, if you create a 2G object on an OSD device,
+	  you can then use this module to present that 2G object as
+	  a Linux block device.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called osdblk.
+
+	  If unsure, say N.
+
 config BLK_DEV_SX8
 	tristate "Promise SATA SX8 support"
 	depends on PCI

drivers/block/Makefile +1 -0

index 7755a5e..cdaa3f8 100644
@@ -23,6 +23,7 @@ obj-$(CONFIG_XILINX_SYSACE)	+= xsysace.o
 obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
 obj-$(CONFIG_MG_DISK)		+= mg_disk.o
 obj-$(CONFIG_SUNVDC)		+= sunvdc.o
+obj-$(CONFIG_BLK_DEV_OSD)	+= osdblk.o
 
 obj-$(CONFIG_BLK_DEV_UMEM)	+= umem.o
 obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o

drivers/block/osdblk.c new file +111 -0

new file mode 100644
index 0000000..c7a1bb7
@@ -0,0 +1,669 @@
+
+/*
+   osdblk.c -- Export a single SCSI OSD object as a Linux block device
+
+
+   Copyright 2009 Red Hat, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING.  If not, write to
+   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+   Instructions for use
+   --------------------
+
+   1) Map a Linux block device to an existing OSD object.
+
+      In this example, we will use partition id 1234, object id 5678,
+      OSD device /dev/osd1.
+
+      $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add
+
+
+   2) List all active blkdev<->object mappings.
+
+      In this example, we have performed step #1 twice, creating two blkdevs,
+      mapped to two separate OSD objects.
+
+      $ cat /sys/class/osdblk/list
+      0 174 1234 5678 /dev/osd1
+      1 179 1994 897123 /dev/osd0
+
+      The columns, in order, are:
+      - blkdev unique id
+      - blkdev assigned major
+      - OSD object partition id
+      - OSD object id
+      - OSD device
+
+
+   3) Remove an active blkdev<->object mapping.
+
+      In this example, we remove the mapping with blkdev unique id 1.
+
+      $ echo 1 > /sys/class/osdblk/remove
+
+
+   NOTE:  The actual creation and deletion of OSD objects is outside the scope
+   of this driver.
+
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <scsi/osd_initiator.h>
+#include <scsi/osd_attributes.h>
+#include <scsi/osd_sec.h>
+
+#define DRV_NAME "osdblk"
+#define PFX DRV_NAME ": "
+
+struct osdblk_device;
+
+enum {
+	OSDBLK_MINORS_PER_MAJOR	= 256,		/* max minors per blkdev */
+	OSDBLK_MAX_REQ		= 32,		/* max parallel requests */
+	OSDBLK_OP_TIMEOUT	= 4 * 60,	/* sync OSD req timeout */
+};
+
+struct osdblk_request {
+	struct request		*rq;		/* blk layer request */
+	struct bio		*bio;		/* cloned bio */
+	struct osdblk_device	*osdev;		/* associated blkdev */
+};
+
+struct osdblk_device {
+	int			id;		/* blkdev unique id */
+
+	int			major;		/* blkdev assigned major */
+	struct gendisk		*disk;		/* blkdev's gendisk and rq */
+	struct request_queue	*q;
+
+	struct osd_dev		*osd;		/* associated OSD */
+
+	char			name[32];	/* blkdev name, e.g. osdblk34 */
+
+	spinlock_t		lock;		/* queue lock */
+
+	struct osd_obj_id	obj;		/* OSD partition, obj id */
+	uint8_t			obj_cred[OSD_CAP_LEN]; /* OSD cred */
+
+	struct osdblk_request	req[OSDBLK_MAX_REQ]; /* request table */
+
+	struct list_head	node;
+
+	char			osd_path[0];	/* OSD device path */
+};
+
+static struct class *class_osdblk;		/* /sys/class/osdblk */
+static struct mutex ctl_mutex;	/* Serialize open/close/setup/teardown */

drivers/block/osdblk.c new file +25 -0

+/*
+ * Perform a synchronous OSD operation.  copied from exofs; move to libosd?
+ */
+static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
+{
+	int ret;
+
+	or->timeout = timeout;
+	ret = osd_finalize_request(or, 0, credential, NULL);
+	if (ret)
+		return ret;
+
+	ret = osd_execute_request(or);
+
+	/* osd_req_decode_sense(or, ret); */
+	return ret;
+}
+
+/*
+ * Perform an asynchronous OSD operation.  copied from exofs; move to libosd?
+ */
+static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done,
+		   void *caller_context, u8 *cred)
+{
+	int ret;

drivers/block/osdblk.c new file +11 -0

+/* copied from exofs; move to libosd? */
+static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
+{
+	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
+	void *iter = NULL;
+	int nelem;
+
+	do {
+		nelem = 1;
+		osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter);
+		if ((cur_attr.attr_page == attr->attr_page) &&

drivers/block/osdblk.c new file +50 -0

+static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out)
+{
+	struct osd_request *or;
+	struct osd_attr attr;
+	int ret;
+
+	/* start request */
+	or = osd_start_request(osdev->osd, GFP_KERNEL);
+	if (!or)
+		return -ENOMEM;
+
+	/* create a get-attributes(length) request */
+	osd_req_get_attributes(or, &osdev->obj);
+
+	osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);
+
+	/* execute op synchronously */
+	ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred);
+	if (ret)
+		goto out;
+
+	/* extract length from returned attribute info */
+	attr = g_attr_logical_length;
+	ret = extract_attr_from_req(or, &attr);
+	if (ret)
+		goto out;
+
+	*size_out = get_unaligned_be64(attr.val_ptr);
+
+out:
+	osd_end_request(or);
+	return ret;
+
+}
+
+static void osdblk_end_request(struct osdblk_device *osdev,
+			       struct osdblk_request *orq,
+			       int error)
+{
+	struct request *rq = orq->rq;
+	int rc;
+
+	/* complete request, at block layer */
+	rc = __blk_end_request(rq, error, blk_rq_bytes(rq));
+}
+
+static void osdblk_osd_complete(struct osd_request *or, void *private)
+{
+	struct osdblk_request *orq = private;
+	struct osd_sense_info osi;

drivers/block/osdblk.c new file +4 -0

+}
+
+static void bio_chain_put(struct bio *chain)
+{

drivers/block/osdblk.c new file +17 -0

+static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask)
+{
+	struct bio *tmp, *new_chain = NULL, *tail = NULL;
+
+	while (old_chain) {
+		tmp = bio_clone(old_chain, gfpmask);
+		if (!tmp)
+			goto err_out;
+
+		tmp->bi_next = NULL;
+		if (!new_chain)
+			new_chain = tail = tmp;
+		else {
+			tail->bi_next = tmp;
+			tail = tmp;
+		}
+

drivers/block/osdblk.c new file +19 -0

+static void osdblk_rq_fn(struct request_queue *q)
+{
+	struct osdblk_device *osdev = q->queuedata;
+	struct request *rq;
+	struct osdblk_request *orq;
+	struct osd_request *or;
+	struct bio *bio;
+	int do_write, do_flush;
+
+	while (1) {
+		/* peek at request from block layer */
+		rq = elv_next_request(q);
+		if (!rq)
+			break;
+
+		/* filter out block requests we don't understand */
+		if (!blk_fs_request(rq) && !blk_barrier_rq(rq)) {
+			end_request(rq, 0);
+			continue;

drivers/block/osdblk.c new file +7 -0

+
+		/* alloc internal OSD request, for OSD command execution */
+		or = osd_start_request(osdev->osd, GFP_ATOMIC);
+		if (!or) {
+			bio_chain_put(bio);
+			break;
+		}

drivers/block/osdblk.c new file +11 -0

+		/* begin OSD command execution */
+		if (osd_async_op(or, osdblk_osd_complete, orq,
+				 osdev->obj_cred)) {
+			osd_end_request(or);
+			blk_requeue_request(q, rq);
+			bio_chain_put(bio);
+		}
+
+		/* remove the special 'flush' marker, now that the command
+		 * is executing
+		 */

drivers/block/osdblk.c new file +295 -0

+}
+
+static void osdblk_free_disk(struct osdblk_device *osdev)
+{
+	struct gendisk *disk = osdev->disk;
+
+	if (!disk)
+		return;
+
+	if (disk->flags & GENHD_FL_UP)
+		del_gendisk(disk);
+	if (disk->queue)
+		blk_cleanup_queue(disk->queue);
+	put_disk(disk);
+}
+
+static int osdblk_init_disk(struct osdblk_device *osdev)
+{
+	struct gendisk *disk;
+	struct request_queue *q;
+	int rc;
+	u64 obj_size = 0;
+
+	/* contact OSD, request size info about the object being mapped */
+	rc = osdblk_get_obj_size(osdev, &obj_size);
+	if (rc)
+		return rc;
+
+	/* create gendisk info */
+	disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR);
+	if (!disk)
+		return -ENOMEM;
+
+	sprintf(disk->disk_name, DRV_NAME "/%d", osdev->id);
+	disk->major = osdev->major;
+	disk->first_minor = 0;
+	disk->fops = &osdblk_bd_ops;
+	disk->private_data = osdev;
+
+	/* init rq */
+	q = blk_init_queue(osdblk_rq_fn, &osdev->lock);
+	if (!q) {
+		put_disk(disk);
+		return -ENOMEM;
+	}
+
+	/* switch queue to TCQ mode; allocate tag map */
+	rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL);
+	if (rc) {
+		blk_cleanup_queue(q);
+		put_disk(disk);
+		return rc;
+	}
+
+	blk_queue_prep_rq(q, blk_queue_start_tag);
+	blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH, osdblk_prepare_flush);
+
+	disk->queue = q;
+
+	q->queuedata = osdev;
+
+	osdev->disk = disk;
+	osdev->q = q;
+
+	/* finally, announce the disk to the world */
+	set_capacity(disk, obj_size);
+	add_disk(disk);
+
+	return 0;
+}
+
+/********************************************************************
+  /sys/class/osdblk/
+                     add	map OSD object to blkdev
+                     remove	unmap OSD object
+                     list	show mappings
+ *******************************************************************/
+
+static void class_osdblk_release(struct class *cls)
+{
+	kfree(cls);
+}
+
+static ssize_t class_osdblk_list(struct class *c, char *data)
+{
+	int n = 0;
+	struct list_head *tmp;
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	list_for_each(tmp, &osdblkdev_list) {
+		struct osdblk_device *osdev;
+
+		osdev = list_entry(tmp, struct osdblk_device, node);
+
+		n += sprintf(data+n, "%d %d %llu %llu %s\n",
+			osdev->id,
+			osdev->major,
+			osdev->obj.partition,
+			osdev->obj.id,
+			osdev->osd_path);
+	}
+
+	mutex_unlock(&ctl_mutex);
+	return n;
+}
+
+static ssize_t class_osdblk_add(struct class *c, const char *buf, size_t count)
+{
+	struct osdblk_device *osdev;
+	ssize_t rc;
+	int irc, new_id = 0;
+	struct list_head *tmp;
+
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
+	/* new osdblk_device object */
+	osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL);
+	if (!osdev) {
+		rc = -ENOMEM;
+		goto err_out_mod;
+	}
+
+	/* static osdblk_device initialization */
+	spin_lock_init(&osdev->lock);
+	INIT_LIST_HEAD(&osdev->node);
+
+	/* generate unique id: find highest unique id, add one */
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	list_for_each(tmp, &osdblkdev_list) {
+		struct osdblk_device *osdev;
+
+		osdev = list_entry(tmp, struct osdblk_device, node);
+		if (osdev->id > new_id)
+			new_id = osdev->id + 1;
+	}
+
+	osdev->id = new_id;
+
+	/* add to global list */
+	list_add_tail(&osdev->node, &osdblkdev_list);
+
+	mutex_unlock(&ctl_mutex);
+
+	/* parse add command */
+	if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id,
+		   osdev->osd_path) != 3) {
+		rc = -EINVAL;
+		goto err_out_slot;
+	}
+
+	/* initialize rest of new object */
+	sprintf(osdev->name, DRV_NAME "%d", osdev->id);
+
+	/* contact requested OSD */
+	osdev->osd = osduld_path_lookup(osdev->osd_path);
+	if (IS_ERR(osdev->osd)) {
+		rc = PTR_ERR(osdev->osd);
+		goto err_out_slot;
+	}
+
+	/* build OSD credential */
+	osd_make_credential(osdev->obj_cred, &osdev->obj);
+
+	/* register our block device */
+	irc = register_blkdev(0, osdev->name);
+	if (irc < 0) {
+		rc = irc;
+		goto err_out_osd;
+	}
+
+	osdev->major = irc;
+
+	/* set up and announce blkdev mapping */
+	rc = osdblk_init_disk(osdev);
+	if (rc)
+		goto err_out_blkdev;
+
+	return 0;
+
+err_out_blkdev:
+	unregister_blkdev(osdev->major, osdev->name);
+err_out_osd:
+	osduld_put_device(osdev->osd);
+err_out_slot:
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+	list_del_init(&osdev->node);
+	mutex_unlock(&ctl_mutex);
+
+	kfree(osdev);
+err_out_mod:
+	module_put(THIS_MODULE);
+	return rc;
+}
+
+static ssize_t class_osdblk_remove(struct class *c, const char *buf,
+					size_t count)
+{
+	struct osdblk_device *osdev = NULL;
+	int target_id, rc;
+	unsigned long ul;
+	struct list_head *tmp;
+
+	rc = strict_strtoul(buf, 10, &ul);
+	if (rc)
+		return rc;
+
+	/* convert to int; abort if we lost anything in the conversion */
+	target_id = (int) ul;
+	if (target_id != ul)
+		return -EINVAL;
+
+	/* remove object from list immediately */
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	list_for_each(tmp, &osdblkdev_list) {
+		osdev = list_entry(tmp, struct osdblk_device, node);
+		if (osdev->id == target_id) {
+			list_del_init(&osdev->node);
+			break;
+		}
+		osdev = NULL;
+	}
+
+	mutex_unlock(&ctl_mutex);
+
+	if (!osdev)
+		return -ENOENT;
+
+	/* clean up and free blkdev and associated OSD connection */
+	osdblk_free_disk(osdev);
+	unregister_blkdev(osdev->major, osdev->name);
+	osduld_put_device(osdev->osd);
+	kfree(osdev);
+
+	/* release module ref */
+	module_put(THIS_MODULE);
+
+	return 0;
+}
+
+static struct class_attribute class_osdblk_attrs[] = {
+	__ATTR(add,	0200, NULL, class_osdblk_add),
+	__ATTR(remove,	0200, NULL, class_osdblk_remove),
+	__ATTR(list,	0444, class_osdblk_list, NULL),
+	__ATTR_NULL
+};
+
+static int osdblk_sysfs_init(void)
+{
+	int ret = 0;
+
+	/*
+	 * create control files in sysfs
+	 * /sys/class/osdblk/...
+	 */
+	class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL);
+	if (!class_osdblk)
+		return -ENOMEM;
+
+	class_osdblk->name = DRV_NAME;
+	class_osdblk->owner = THIS_MODULE;
+	class_osdblk->class_release = class_osdblk_release;
+	class_osdblk->class_attrs = class_osdblk_attrs;
+
+	ret = class_register(class_osdblk);
+	if (ret) {
+		kfree(class_osdblk);
+		class_osdblk = NULL;
+		printk(PFX "failed to create class osdblk\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void osdblk_sysfs_cleanup(void)
+{
+	if (class_osdblk)
+		class_destroy(class_osdblk);
+	class_osdblk = NULL;
+}
+
+static int __init osdblk_init(void)
+{
+	int rc;
+
+	rc = osdblk_sysfs_init();
+	if (rc)
+		return rc;
+
+	return 0;

Quoted 22 lines

drivers/block/osdblk.c new file +22 -0

+static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask)
+{
+	struct bio *tmp, *new_chain = NULL, *tail = NULL;
+
+	while (old_chain) {
+		tmp = bio_clone(old_chain, gfpmask);
+		if (!tmp)
+			goto err_out;
+
+		tmp->bi_next = NULL;
+		if (!new_chain)
+			new_chain = tail = tmp;
+		else {
+			tail->bi_next = tmp;
+			tail = tmp;
+		}
+
+		old_chain = old_chain->bi_next;
+	}
+
+	return new_chain;
+

drivers/block/osdblk.c line 284

Quoted 5 lines

drivers/block/osdblk.c new file +5 -0

+err_out:
+	bio_chain_put(new_chain);
+	return NULL;
+}
+

NOTE-TO-ME:
blk_bio_clone()

Quoted 19 lines

drivers/block/osdblk.c new file +19 -0

+static void osdblk_rq_fn(struct request_queue *q)
+{
+	struct osdblk_device *osdev = q->queuedata;
+	struct request *rq;
+	struct osdblk_request *orq;
+	struct osd_request *or;
+	struct bio *bio;
+	int do_write, do_flush;
+
+	while (1) {
+		/* peek at request from block layer */
+		rq = elv_next_request(q);
+		if (!rq)
+			break;
+
+		/* filter out block requests we don't understand */
+		if (!blk_fs_request(rq) && !blk_barrier_rq(rq)) {
+			end_request(rq, 0);
+			continue;

drivers/block/osdblk.c line 313

Quoted 10 lines

drivers/block/osdblk.c new file +10 -0

+		}
+
+		/* deduce our operation (read, write, flush) */
+		/* I wish the block layer simplified cmd_type/cmd_flags/cmd[]
+		 * into a clearly defined set of RPC commands:
+		 * read, write, flush, scsi command, power mgmt req,
+		 * driver-specific, etc.
+		 */
+
+		do_flush = (rq->special == (void *) 0xdeadbeefUL);

That's for real? or it needs a "FIXME" next to it?

drivers/block/osdblk.c line 319

Quoted 6 lines

drivers/block/osdblk.c new file +6 -0

+		do_write = (rq_data_dir(rq) == WRITE);
+
+		/* a bio clone to be passed down to OSD request */
+		bio = bio_chain_clone(rq->bio, GFP_ATOMIC);
+		if (!bio)
+			break;

does blk_barrier_rq() have a rq->bio?

On Mon, Apr 27 2009, Boaz Harrosh wrote:

Quoted 21 lines

Quoted 21 lines

drivers/block/osdblk.c new file +21 -0

+static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask)
+{
+	struct bio *tmp, *new_chain = NULL, *tail = NULL;
+
+	while (old_chain) {
+		tmp = bio_clone(old_chain, gfpmask);
+		if (!tmp)
+			goto err_out;
+
+		tmp->bi_next = NULL;
+		if (!new_chain)
+			new_chain = tail = tmp;
+		else {
+			tail->bi_next = tmp;
+			tail = tmp;
+		}
+
+		old_chain = old_chain->bi_next;
+	}
+
+	return new_chain;

Quoted 8 lines

drivers/block/osdblk.c line 284

Quoted 6 lines

drivers/block/osdblk.c new file +6 -0

+
+err_out:
+	bio_chain_put(new_chain);
+	return NULL;
+}
+

NOTE-TO-ME:
blk_bio_clone()

Note to Boaz - this is illegal, unless gfp_mask is GFP_ATOMIC (in which case you should not pass it in).

The only way to make this work is to:

1) Have a private bio pool, and

2) Make sure it has enough reserved entries to populate the chain

3) Ensure only a single caller at the time, or entries enough for the N users that are allowed. It has to be controlled either way, whether N is 1 or larger.

Signed-off-by Jeff Garzik <[email protected]>

---
 drivers/scsi/osd/osd_initiator.c |   83 +++++++++++++++++++++++++++++++--------
 1 file changed, 67 insertions(+), 16 deletions(-)

drivers/scsi/osd/osd_initiator.c +2 -0

index 2a5f077..2d35d65 100644
@@ -709,14 +709,36 @@ EXPORT_SYMBOL(osd_req_remove_object);
 	struct osd_obj_id *first, struct osd_obj_id_list *list, unsigned nelem);
 */
 
+static unsigned int bio_chain_size(struct bio *bio)
+{

drivers/scsi/osd/osd_initiator.c +3 -2

+	_osd_req_encode_common(or, OSD_ACT_READ, obj, offset, chain_size);
 	WARN_ON(or->in.bio || or->in.total_bytes);
-	bio->bi_rw &= ~(1 << BIO_RW);
+
 	or->in.bio = bio;
-	or->in.total_bytes = bio->bi_size;
+	or->in.total_bytes = chain_size;
 }
 EXPORT_SYMBOL(osd_req_read);
 

drivers/scsi/osd/osd_initiator.c +15 -9

 		or->out_data_integ.set_attributes_bytes = cpu_to_be64(
 			or->set_attr.total_bytes);
 		or->out_data_integ.get_attributes_bytes = cpu_to_be64(

@@ -1269,6 +1301,7 @@ int osd_finalize_request(struct osd_request *or,
 	struct osd_cdb_head *cdbh = osd_cdb_head(&or->cdb);
 	bool has_in, has_out;
 	int ret;
+	struct bio *bio, *tmp;
 
 	if (options & OSD_REQ_FUA)
 		cdbh->options |= OSD_CDB_FUA;

@@ -1292,23 +1325,40 @@ int osd_finalize_request(struct osd_request *or,
 	}
 
 	if (or->out.bio) {
-		ret = blk_rq_append_bio(or->request->q, or->out.req,
-					or->out.bio);
-		if (ret) {
-			OSD_DEBUG("blk_rq_append_bio out failed\n");
-			return ret;
+		bio = or->out.bio;
+		while (bio) {
+			tmp = bio;
+			bio = bio->bi_next;
+
+			ret = blk_rq_append_bio(or->request->q, or->out.req,
+						tmp);
+			if (ret) {
+				OSD_DEBUG("blk_rq_append_bio out failed\n");
+				return ret;
+			}
 		}
 		OSD_DEBUG("out bytes=%llu (bytes_req=%u)\n",
 			_LLU(or->out.total_bytes), or->out.req->data_len);
+
+		or->out.bio = NULL;
 	}
 	if (or->in.bio) {
-		ret = blk_rq_append_bio(or->request->q, or->in.req, or->in.bio);
-		if (ret) {
-			OSD_DEBUG("blk_rq_append_bio in failed\n");
-			return ret;
+		bio = or->in.bio;