pnfs-obj: objio_osd device information retrieval and caching

When a new layout is received in objio_alloc_lseg all device_ids
referenced are retrieved. The device information is queried for from MDS
and then the osd_device is looked-up from the osd-initiator library. The
devices are cached in a per-mount-point list, for later use. At unmount
all devices are "put" back to the library.

objlayout_get_deviceinfo(), objlayout_put_deviceinfo() middleware
API for retrieving device information given a device_id.

TODO: The device cache can get big. Cap its size. Keep an LRU and start
      to return devices which were not used, when list gets to big, or
      when new entries allocation fail.

[pnfs-obj: Bugs in new global-device-cache code]
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
[gfp_flags]
[use global device cache]
[use layout driver in global device cache]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

fs/nfs/objlayout/objio_osd.c

@@ -46,6 +46,68 @@
 
 #define _LLU(x) ((unsigned long long)x)
 
+struct objio_dev_ent {
+	struct nfs4_deviceid_node id_node;
+	struct osd_dev *od;
+};
+
+static void
+objio_free_deviceid_node(struct nfs4_deviceid_node *d)
+{
+	struct objio_dev_ent *de = container_of(d, struct objio_dev_ent, id_node);
+
+	dprintk("%s: free od=%p\n", __func__, de->od);
+	osduld_put_device(de->od);
+	kfree(de);
+}
+
+static struct objio_dev_ent *_dev_list_find(const struct nfs_server *nfss,
+	const struct nfs4_deviceid *d_id)
+{
+	struct nfs4_deviceid_node *d;
+	struct objio_dev_ent *de;
+
+	d = nfs4_find_get_deviceid(nfss->pnfs_curr_ld, nfss->nfs_client, d_id);
+	if (!d)
+		return NULL;
+
+	de = container_of(d, struct objio_dev_ent, id_node);
+	return de;
+}
+
+static struct objio_dev_ent *
+_dev_list_add(const struct nfs_server *nfss,
+	const struct nfs4_deviceid *d_id, struct osd_dev *od,
+	gfp_t gfp_flags)
+{
+	struct nfs4_deviceid_node *d;
+	struct objio_dev_ent *de = kzalloc(sizeof(*de), gfp_flags);
+	struct objio_dev_ent *n;
+
+	if (!de) {
+		dprintk("%s: -ENOMEM od=%p\n", __func__, od);
+		return NULL;
+	}
+
+	dprintk("%s: Adding od=%p\n", __func__, od);
+	nfs4_init_deviceid_node(&de->id_node,
+				nfss->pnfs_curr_ld,
+				nfss->nfs_client,
+				d_id);
+	de->od = od;
+
+	d = nfs4_insert_deviceid_node(&de->id_node);
+	n = container_of(d, struct objio_dev_ent, id_node);
+	if (n != de) {
+		dprintk("%s: Race with other n->od=%p\n", __func__, n->od);
+		objio_free_deviceid_node(&de->id_node);
+		de = n;
+	}
+
+	atomic_inc(&de->id_node.ref);
+	return de;
+}
+
 struct caps_buffers {
 	u8 caps_key[OSD_CRYPTO_KEYID_SIZE];
 	u8 creds[OSD_CAP_LEN];
@@ -74,6 +136,90 @@ OBJIO_LSEG(struct pnfs_layout_segment *lseg)
 	return container_of(lseg, struct objio_segment, lseg);
 }
 
+/* Send and wait for a get_device_info of devices in the layout,
+   then look them up with the osd_initiator library */
+static struct objio_dev_ent *_device_lookup(struct pnfs_layout_hdr *pnfslay,
+				struct objio_segment *objio_seg, unsigned comp,
+				gfp_t gfp_flags)
+{
+	struct pnfs_osd_deviceaddr *deviceaddr;
+	struct nfs4_deviceid *d_id;
+	struct objio_dev_ent *ode;
+	struct osd_dev *od;
+	struct osd_dev_info odi;
+	int err;
+
+	d_id = &objio_seg->comps[comp].oc_object_id.oid_device_id;
+
+	ode = _dev_list_find(NFS_SERVER(pnfslay->plh_inode), d_id);
+	if (ode)
+		return ode;
+
+	err = objlayout_get_deviceinfo(pnfslay, d_id, &deviceaddr, gfp_flags);
+	if (unlikely(err)) {
+		dprintk("%s: objlayout_get_deviceinfo dev(%llx:%llx) =>%d\n",
+			__func__, _DEVID_LO(d_id), _DEVID_HI(d_id), err);
+		return ERR_PTR(err);
+	}
+
+	odi.systemid_len = deviceaddr->oda_systemid.len;
+	if (odi.systemid_len > sizeof(odi.systemid)) {
+		err = -EINVAL;
+		goto out;
+	} else if (odi.systemid_len)
+		memcpy(odi.systemid, deviceaddr->oda_systemid.data,
+		       odi.systemid_len);
+	odi.osdname_len	 = deviceaddr->oda_osdname.len;
+	odi.osdname	 = (u8 *)deviceaddr->oda_osdname.data;
+
+	if (!odi.osdname_len && !odi.systemid_len) {
+		dprintk("%s: !odi.osdname_len && !odi.systemid_len\n",
+			__func__);
+		err = -ENODEV;
+		goto out;
+	}
+
+	od = osduld_info_lookup(&odi);
+	if (unlikely(IS_ERR(od))) {
+		err = PTR_ERR(od);
+		dprintk("%s: osduld_info_lookup => %d\n", __func__, err);
+		goto out;
+	}
+
+	ode = _dev_list_add(NFS_SERVER(pnfslay->plh_inode), d_id, od,
+			    gfp_flags);
+
+out:
+	dprintk("%s: return=%d\n", __func__, err);
+	objlayout_put_deviceinfo(deviceaddr);
+	return err ? ERR_PTR(err) : ode;
+}
+
+static int objio_devices_lookup(struct pnfs_layout_hdr *pnfslay,
+	struct objio_segment *objio_seg,
+	gfp_t gfp_flags)
+{
+	unsigned i;
+	int err;
+
+	/* lookup all devices */
+	for (i = 0; i < objio_seg->num_comps; i++) {
+		struct objio_dev_ent *ode;
+
+		ode = _device_lookup(pnfslay, objio_seg, i, gfp_flags);
+		if (unlikely(IS_ERR(ode))) {
+			err = PTR_ERR(ode);
+			goto out;
+		}
+		objio_seg->ods[i] = ode;
+	}
+	err = 0;
+
+out:
+	dprintk("%s: return=%d\n", __func__, err);
+	return err;
+}
+
 static int _verify_data_map(struct pnfs_osd_layout *layout)
 {
 	struct pnfs_osd_data_map *data_map = &layout->olo_map;
@@ -171,6 +317,9 @@ int objio_alloc_lseg(struct pnfs_layout_segment **outp,
 
 	objio_seg->num_comps = layout.olo_num_comps;
 	objio_seg->comps_index = layout.olo_comps_index;
+	err = objio_devices_lookup(pnfslay, objio_seg, gfp_flags);
+	if (err)
+		goto err;
 
 	objio_seg->mirrors_p1 = layout.olo_map.odm_mirror_cnt + 1;
 	objio_seg->stripe_unit = layout.olo_map.odm_stripe_unit;
@@ -199,8 +348,14 @@ err:
 
 void objio_free_lseg(struct pnfs_layout_segment *lseg)
 {
+	int i;
 	struct objio_segment *objio_seg = OBJIO_LSEG(lseg);
 
+	for (i = 0; i < objio_seg->num_comps; i++) {
+		if (!objio_seg->ods[i])
+			break;
+		nfs4_put_deviceid_node(&objio_seg->ods[i]->id_node);
+	}
 	kfree(objio_seg);
 }
 
@@ -211,6 +366,8 @@ static struct pnfs_layoutdriver_type objlayout_type = {
 
 	.alloc_lseg              = objlayout_alloc_lseg,
 	.free_lseg               = objlayout_free_lseg,
+
+	.free_deviceid_node	 = objio_free_deviceid_node,
 };
 
 MODULE_DESCRIPTION("pNFS Layout Driver for OSD2 objects");

fs/nfs/objlayout/objlayout.c

@@ -102,3 +102,71 @@ objlayout_free_lseg(struct pnfs_layout_segment *lseg)
 	objio_free_lseg(lseg);
 }
 
+/*
+ * Get Device Info API for io engines
+ */
+struct objlayout_deviceinfo {
+	struct page *page;
+	struct pnfs_osd_deviceaddr da; /* This must be last */
+};
+
+/* Initialize and call nfs_getdeviceinfo, then decode and return a
+ * "struct pnfs_osd_deviceaddr *" Eventually objlayout_put_deviceinfo()
+ * should be called.
+ */
+int objlayout_get_deviceinfo(struct pnfs_layout_hdr *pnfslay,
+	struct nfs4_deviceid *d_id, struct pnfs_osd_deviceaddr **deviceaddr,
+	gfp_t gfp_flags)
+{
+	struct objlayout_deviceinfo *odi;
+	struct pnfs_device pd;
+	struct super_block *sb;
+	struct page *page, **pages;
+	u32 *p;
+	int err;
+
+	page = alloc_page(gfp_flags);
+	if (!page)
+		return -ENOMEM;
+
+	pages = &page;
+	pd.pages = pages;
+
+	memcpy(&pd.dev_id, d_id, sizeof(*d_id));
+	pd.layout_type = LAYOUT_OSD2_OBJECTS;
+	pd.pages = &page;
+	pd.pgbase = 0;
+	pd.pglen = PAGE_SIZE;
+	pd.mincount = 0;
+
+	sb = pnfslay->plh_inode->i_sb;
+	err = nfs4_proc_getdeviceinfo(NFS_SERVER(pnfslay->plh_inode), &pd);
+	dprintk("%s nfs_getdeviceinfo returned %d\n", __func__, err);
+	if (err)
+		goto err_out;
+
+	p = page_address(page);
+	odi = kzalloc(sizeof(*odi), gfp_flags);
+	if (!odi) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+	pnfs_osd_xdr_decode_deviceaddr(&odi->da, p);
+	odi->page = page;
+	*deviceaddr = &odi->da;
+	return 0;
+
+err_out:
+	__free_page(page);
+	return err;
+}
+
+void objlayout_put_deviceinfo(struct pnfs_osd_deviceaddr *deviceaddr)
+{
+	struct objlayout_deviceinfo *odi = container_of(deviceaddr,
+						struct objlayout_deviceinfo,
+						da);
+
+	__free_page(odi->page);
+	kfree(odi);
+}

fs/nfs/objlayout/objlayout.h

@@ -55,6 +55,14 @@ extern int objio_alloc_lseg(struct pnfs_layout_segment **outp,
 	gfp_t gfp_flags);
 extern void objio_free_lseg(struct pnfs_layout_segment *lseg);
 
+/*
+ * callback API
+ */
+extern int objlayout_get_deviceinfo(struct pnfs_layout_hdr *pnfslay,
+	struct nfs4_deviceid *d_id, struct pnfs_osd_deviceaddr **deviceaddr,
+	gfp_t gfp_flags);
+extern void objlayout_put_deviceinfo(struct pnfs_osd_deviceaddr *deviceaddr);
+
 /*
  * exported generic objects function vectors
  */