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/*
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 <linux/slab.h>
#include <scsi/osd_initiator.h>
#include <scsi/osd_attributes.h>
#include <scsi/osd_sec.h>
#include <scsi/scsi_device.h>
#define DRV_NAME "osdblk"
#define PFX DRV_NAME ": "
/* #define _OSDBLK_DEBUG */
#ifdef _OSDBLK_DEBUG
#define OSDBLK_DEBUG(fmt, a...) \
printk(KERN_NOTICE "osdblk @%s:%d: " fmt, __func__, __LINE__, ##a)
#else
#define OSDBLK_DEBUG(fmt, a...) \
do { if (0) printk(fmt, ##a); } while (0)
#endif
MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
MODULE_DESCRIPTION("block device inside an OSD object osdblk.ko");
MODULE_LICENSE("GPL");
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 DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */
static LIST_HEAD(osdblkdev_list);
static const struct block_device_operations osdblk_bd_ops = {
.owner = THIS_MODULE,
};
static const struct osd_attr g_attr_logical_length = ATTR_DEF(
OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
static void osdblk_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);
}
/* copied from exofs; move to libosd? */
/*
* 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;
ret = osd_finalize_request(or, 0, cred, NULL);
if (ret)
return ret;
ret = osd_execute_request_async(or, async_done, caller_context);
return ret;
}
/* 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) &&
(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;
/* 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_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;
OSDBLK_DEBUG("osdblk_osd_complete with err=%d\n", ret);
}
/* complete OSD request */
osd_end_request(or);
/* complete request passed to osdblk by block layer */
__blk_end_request_all(orq->rq, ret);
}
static void bio_chain_put(struct bio *chain)
{
struct bio *tmp;
while (chain) {
tmp = chain;
chain = chain->bi_next;
bio_put(tmp);
}
}
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_kmalloc(gfpmask, old_chain->bi_max_vecs);
if
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