[SCSI] libosd: osd_dev_info: Unique Identification of an OSD device

Define an osd_dev_info structure that Uniquely identifies an OSD
device lun on the network. The identification is built from unique
target attributes and is the same for all network/SAN machines.

osduld_info_lookup() - NEW
    New API that will lookup an osd_dev by its osd_dev_info.
    This is used by pNFS-objects for cross network global device
    identification. And by exofs multy-device support, the device
    info is specified in the on-disk exofs device table.

osduld_device_info() - NEW
    Given an osd_dev handle returns its associated osd_dev_info.
    The ULD fetches this information at startup and hangs it on
    each OSD device. (This is a fast operation that can be called
    at any condition)

osduld_device_same() - NEW
    With a given osd_dev at one hand and an osd_dev_info
    at another, we would like to know if they are the same
    device.
    Two osd_dev handles can be checked by:
        osduld_device_same(od1, osduld_device_info(od2));

osd_auto_detect_ver() - REVISED
    Now returns an osd_dev_info structure. Is only called once
    by ULD as before. See added comments for how to use.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 20 insertions, 6 deletions

diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 7a117c18114..60b7ca1e9bc 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -73,7 +73,8 @@ static const char *_osd_ver_desc(struct osd_request *or)
 
 #define ATTR_DEF_RI(id, len) ATTR_DEF(OSD_APAGE_ROOT_INFORMATION, id, len)
 
-static int _osd_print_system_info(struct osd_dev *od, void *caps)
+static int _osd_get_print_system_info(struct osd_dev *od,
+        void *caps, struct osd_dev_info *odi)
 {
         struct osd_request *or;
         struct osd_attr get_attrs[] = {
@@ -137,8 +138,12 @@ static int _osd_print_system_info(struct osd_dev *od, void *caps)
         OSD_INFO("PRODUCT_SERIAL_NUMBER  [%s]\n",
                 (char *)pFirst);
 
-        pFirst = get_attrs[a].val_ptr;
-        OSD_INFO("OSD_NAME               [%s]\n", (char *)pFirst);
+        odi->osdname_len = get_attrs[a].len;
+        /* Avoid NULL for memcmp optimization 0-length is good enough */
+        odi->osdname = kzalloc(odi->osdname_len + 1, GFP_KERNEL);
+        if (odi->osdname_len)
+                memcpy(odi->osdname, get_attrs[a].val_ptr, odi->osdname_len);
+        OSD_INFO("OSD_NAME               [%s]\n", odi->osdname);
         a++;
 
         pFirst = get_attrs[a++].val_ptr;
@@ -171,6 +176,14 @@ static int _osd_print_system_info(struct osd_dev *od, void *caps)
                                    sid_dump, sizeof(sid_dump), true);
                 OSD_INFO("OSD_SYSTEM_ID(%d)\n"
                          "        [%s]\n", len, sid_dump);
+
+                if (unlikely(len > sizeof(odi->systemid))) {
+                        OSD_ERR("OSD Target error: OSD_SYSTEM_ID too long(%d). "
+                                "device idetification might not work\n", len);
+                        len = sizeof(odi->systemid);
+                }
+                odi->systemid_len = len;
+                memcpy(odi->systemid, get_attrs[a].val_ptr, len);
                 a++;
         }
 out:
@@ -178,16 +191,17 @@ out:
         return ret;
 }
 
-int osd_auto_detect_ver(struct osd_dev *od, void *caps)
+int osd_auto_detect_ver(struct osd_dev *od,
+        void *caps, struct osd_dev_info *odi)
 {
         int ret;
 
         /* Auto-detect the osd version */
-        ret = _osd_print_system_info(od, caps);
+        ret = _osd_get_print_system_info(od, caps, odi);
         if (ret) {
                 osd_dev_set_ver(od, OSD_VER1);
                 OSD_DEBUG("converting to OSD1\n");
-                ret = _osd_print_system_info(od, caps);
+                ret = _osd_get_print_system_info(od, caps, odi);
         }
 
         return ret;