On Wed, 2009-04-01 at 21:54 -0400, Jeff Garzik wrote:
> 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(+)
>
> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> index e7b8aa0..ff46b0e 100644
> --- a/drivers/block/Kconfig
> +++ b/drivers/block/Kconfig
> @@ -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
> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
> index 3145141..859bf5d 100644
> --- a/drivers/block/Makefile
> +++ b/drivers/block/Makefile
> @@ -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
> diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c
> new file mode 100644
> index 0000000..d3a2fb5
> --- /dev/null
> +++ b/drivers/block/osdblk.c
> @@ -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
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?
> + 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];
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
> +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;
> +
> +}
> +
> +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
The rest looks fine.
James
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