James Bottomley wrote:
+ 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?
Yeah... I leaned more towards a consolidated table, as it was
elegantly implemented in just a few lines of code, including locking :)
+ 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.
+
+ 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
converted to list
+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
converted to use blk-tag.c gadgetry
Thanks for the review!
Jeff
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