return count;
}
-static struct lnet_ping_info *
-lnet_ping_info_create(int num_ni)
+struct lnet_ping_buffer *
+lnet_ping_buffer_alloc(int nnis, gfp_t gfp)
{
- struct lnet_ping_info *ping_info;
- unsigned int infosz;
+ struct lnet_ping_buffer *pbuf;
- infosz = offsetof(struct lnet_ping_info, pi_ni[num_ni]);
- LIBCFS_ALLOC(ping_info, infosz);
- if (ping_info == NULL) {
- CERROR("Can't allocate ping info[%d]\n", num_ni);
+ LIBCFS_ALLOC_GFP(pbuf, LNET_PING_BUFFER_SIZE(nnis), gfp);
+ if (pbuf) {
+ pbuf->pb_nnis = nnis;
+ atomic_set(&pbuf->pb_refcnt, 1);
+ }
+
+ return pbuf;
+}
+
+void
+lnet_ping_buffer_free(struct lnet_ping_buffer *pbuf)
+{
+ LASSERT(lnet_ping_buffer_numref(pbuf) == 0);
+ LIBCFS_FREE(pbuf, LNET_PING_BUFFER_SIZE(pbuf->pb_nnis));
+}
+
+static struct lnet_ping_buffer *
+lnet_ping_target_create(int nnis)
+{
+ struct lnet_ping_buffer *pbuf;
+
+ pbuf = lnet_ping_buffer_alloc(nnis, GFP_NOFS);
+ if (pbuf == NULL) {
+ CERROR("Can't allocate ping source [%d]\n", nnis);
return NULL;
}
- ping_info->pi_nnis = num_ni;
- ping_info->pi_pid = the_lnet.ln_pid;
- ping_info->pi_magic = LNET_PROTO_PING_MAGIC;
- ping_info->pi_features = LNET_PING_FEAT_NI_STATUS;
+ pbuf->pb_info.pi_nnis = nnis;
+ pbuf->pb_info.pi_pid = the_lnet.ln_pid;
+ pbuf->pb_info.pi_magic = LNET_PROTO_PING_MAGIC;
+ pbuf->pb_info.pi_features = LNET_PING_FEAT_NI_STATUS;
- return ping_info;
+ return pbuf;
}
static inline int
return count;
}
-static inline void
-lnet_ping_info_free(struct lnet_ping_info *pinfo)
+int
+lnet_ping_info_validate(struct lnet_ping_info *pinfo)
{
- LIBCFS_FREE(pinfo,
- offsetof(struct lnet_ping_info,
- pi_ni[pinfo->pi_nnis]));
+ if (!pinfo)
+ return -EINVAL;
+ if (pinfo->pi_magic != LNET_PROTO_PING_MAGIC)
+ return -EPROTO;
+ if (!(pinfo->pi_features & LNET_PING_FEAT_NI_STATUS))
+ return -EPROTO;
+ /* Loopback is guaranteed to be present */
+ if (pinfo->pi_nnis < 1 || pinfo->pi_nnis > lnet_interfaces_max)
+ return -ERANGE;
+ if (LNET_NETTYP(LNET_NIDNET(LNET_PING_INFO_LONI(pinfo))) != LOLND)
+ return -EPROTO;
+ return 0;
}
static void
-lnet_ping_info_destroy(void)
+lnet_ping_target_destroy(void)
{
struct lnet_net *net;
struct lnet_ni *ni;
}
}
- lnet_ping_info_free(the_lnet.ln_ping_info);
- the_lnet.ln_ping_info = NULL;
+ lnet_ping_buffer_decref(the_lnet.ln_ping_target);
+ the_lnet.ln_ping_target = NULL;
lnet_net_unlock(LNET_LOCK_EX);
}
static void
-lnet_ping_event_handler(struct lnet_event *event)
+lnet_ping_target_event_handler(struct lnet_event *event)
{
- struct lnet_ping_info *pinfo = event->md.user_ptr;
+ struct lnet_ping_buffer *pbuf = event->md.user_ptr;
if (event->unlinked)
- pinfo->pi_features = LNET_PING_FEAT_INVAL;
+ lnet_ping_buffer_decref(pbuf);
}
static int
-lnet_ping_info_setup(struct lnet_ping_info **ppinfo,
- struct lnet_handle_md *md_handle,
- int ni_count, bool set_eq)
+lnet_ping_target_setup(struct lnet_ping_buffer **ppbuf,
+ struct lnet_handle_md *ping_mdh,
+ int ni_count, bool set_eq)
{
struct lnet_process_id id = {
.nid = LNET_NID_ANY,
int rc, rc2;
if (set_eq) {
- rc = LNetEQAlloc(0, lnet_ping_event_handler,
+ rc = LNetEQAlloc(0, lnet_ping_target_event_handler,
&the_lnet.ln_ping_target_eq);
if (rc != 0) {
- CERROR("Can't allocate ping EQ: %d\n", rc);
+ CERROR("Can't allocate ping buffer EQ: %d\n", rc);
return rc;
}
}
- *ppinfo = lnet_ping_info_create(ni_count);
- if (*ppinfo == NULL) {
+ *ppbuf = lnet_ping_target_create(ni_count);
+ if (*ppbuf == NULL) {
rc = -ENOMEM;
- goto failed_0;
+ goto fail_free_eq;
}
+ /* Ping target ME/MD */
rc = LNetMEAttach(LNET_RESERVED_PORTAL, id,
LNET_PROTO_PING_MATCHBITS, 0,
LNET_UNLINK, LNET_INS_AFTER,
&me_handle);
if (rc != 0) {
- CERROR("Can't create ping ME: %d\n", rc);
- goto failed_1;
+ CERROR("Can't create ping target ME: %d\n", rc);
+ goto fail_decref_ping_buffer;
}
/* initialize md content */
- md.start = *ppinfo;
- md.length = offsetof(struct lnet_ping_info,
- pi_ni[(*ppinfo)->pi_nnis]);
+ md.start = &(*ppbuf)->pb_info;
+ md.length = LNET_PING_INFO_SIZE((*ppbuf)->pb_nnis);
md.threshold = LNET_MD_THRESH_INF;
md.max_size = 0;
md.options = LNET_MD_OP_GET | LNET_MD_TRUNCATE |
LNET_MD_MANAGE_REMOTE;
- md.user_ptr = NULL;
md.eq_handle = the_lnet.ln_ping_target_eq;
- md.user_ptr = *ppinfo;
+ md.user_ptr = *ppbuf;
- rc = LNetMDAttach(me_handle, md, LNET_RETAIN, md_handle);
+ rc = LNetMDAttach(me_handle, md, LNET_RETAIN, ping_mdh);
if (rc != 0) {
- CERROR("Can't attach ping MD: %d\n", rc);
- goto failed_2;
+ CERROR("Can't attach ping target MD: %d\n", rc);
+ goto fail_unlink_ping_me;
}
+ lnet_ping_buffer_addref(*ppbuf);
return 0;
-failed_2:
+fail_unlink_ping_me:
rc2 = LNetMEUnlink(me_handle);
LASSERT(rc2 == 0);
-failed_1:
- lnet_ping_info_free(*ppinfo);
- *ppinfo = NULL;
-failed_0:
- if (set_eq)
- LNetEQFree(the_lnet.ln_ping_target_eq);
+fail_decref_ping_buffer:
+ LASSERT(lnet_ping_buffer_numref(*ppbuf) == 1);
+ lnet_ping_buffer_decref(*ppbuf);
+ *ppbuf = NULL;
+fail_free_eq:
+ if (set_eq) {
+ rc2 = LNetEQFree(the_lnet.ln_ping_target_eq);
+ LASSERT(rc2 == 0);
+ }
return rc;
}
static void
-lnet_ping_md_unlink(struct lnet_ping_info *pinfo, struct lnet_handle_md *md_handle)
+lnet_ping_md_unlink(struct lnet_ping_buffer *pbuf,
+ struct lnet_handle_md *ping_mdh)
{
sigset_t blocked = cfs_block_allsigs();
- LNetMDUnlink(*md_handle);
- LNetInvalidateMDHandle(md_handle);
+ LNetMDUnlink(*ping_mdh);
+ LNetInvalidateMDHandle(ping_mdh);
- /* NB md could be busy; this just starts the unlink */
- while (pinfo->pi_features != LNET_PING_FEAT_INVAL) {
- CDEBUG(D_NET, "Still waiting for ping MD to unlink\n");
+ /* NB the MD could be busy; this just starts the unlink */
+ while (lnet_ping_buffer_numref(pbuf) > 1) {
+ CDEBUG(D_NET, "Still waiting for ping data MD to unlink\n");
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(cfs_time_seconds(1));
}
}
static void
-lnet_ping_info_install_locked(struct lnet_ping_info *ping_info)
+lnet_ping_target_install_locked(struct lnet_ping_buffer *pbuf)
{
- int i;
struct lnet_ni *ni;
struct lnet_net *net;
struct lnet_ni_status *ns;
+ int i;
+ int rc;
i = 0;
list_for_each_entry(net, &the_lnet.ln_nets, net_list) {
list_for_each_entry(ni, &net->net_ni_list, ni_netlist) {
- LASSERT(i < ping_info->pi_nnis);
+ LASSERT(i < pbuf->pb_nnis);
- ns = &ping_info->pi_ni[i];
+ ns = &pbuf->pb_info.pi_ni[i];
ns->ns_nid = ni->ni_nid;
lnet_ni_lock(ni);
ns->ns_status = (ni->ni_status != NULL) ?
- ni->ni_status->ns_status :
+ ni->ni_status->ns_status :
LNET_NI_STATUS_UP;
ni->ni_status = ns;
lnet_ni_unlock(ni);
i++;
}
-
}
+ /*
+ * We (ab)use the ns_status of the loopback interface to
+ * transmit the sequence number. The first interface listed
+ * must be the loopback interface.
+ */
+ rc = lnet_ping_info_validate(&pbuf->pb_info);
+ if (rc) {
+ LCONSOLE_EMERG("Invalid ping target: %d\n", rc);
+ LBUG();
+ }
+ LNET_PING_BUFFER_SEQNO(pbuf) =
+ atomic_inc_return(&the_lnet.ln_ping_target_seqno);
}
static void
-lnet_ping_target_update(struct lnet_ping_info *pinfo,
- struct lnet_handle_md md_handle)
+lnet_ping_target_update(struct lnet_ping_buffer *pbuf,
+ struct lnet_handle_md ping_mdh)
{
- struct lnet_ping_info *old_pinfo = NULL;
- struct lnet_handle_md old_md;
+ struct lnet_ping_buffer *old_pbuf = NULL;
+ struct lnet_handle_md old_ping_md;
/* switch the NIs to point to the new ping info created */
lnet_net_lock(LNET_LOCK_EX);
if (!the_lnet.ln_routing)
- pinfo->pi_features |= LNET_PING_FEAT_RTE_DISABLED;
- lnet_ping_info_install_locked(pinfo);
+ pbuf->pb_info.pi_features |= LNET_PING_FEAT_RTE_DISABLED;
+ lnet_ping_target_install_locked(pbuf);
- if (the_lnet.ln_ping_info != NULL) {
- old_pinfo = the_lnet.ln_ping_info;
- old_md = the_lnet.ln_ping_target_md;
+ if (the_lnet.ln_ping_target) {
+ old_pbuf = the_lnet.ln_ping_target;
+ old_ping_md = the_lnet.ln_ping_target_md;
}
- the_lnet.ln_ping_target_md = md_handle;
- the_lnet.ln_ping_info = pinfo;
+ the_lnet.ln_ping_target_md = ping_mdh;
+ the_lnet.ln_ping_target = pbuf;
lnet_net_unlock(LNET_LOCK_EX);
- if (old_pinfo != NULL) {
- /* unlink the old ping info */
- lnet_ping_md_unlink(old_pinfo, &old_md);
- lnet_ping_info_free(old_pinfo);
+ if (old_pbuf) {
+ /* unlink and free the old ping info */
+ lnet_ping_md_unlink(old_pbuf, &old_ping_md);
+ lnet_ping_buffer_decref(old_pbuf);
}
}
{
int rc;
- lnet_ping_md_unlink(the_lnet.ln_ping_info,
+ lnet_ping_md_unlink(the_lnet.ln_ping_target,
&the_lnet.ln_ping_target_md);
rc = LNetEQFree(the_lnet.ln_ping_target_eq);
LASSERT(rc == 0);
- lnet_ping_info_destroy();
+ lnet_ping_target_destroy();
}
static int
int im_a_router = 0;
int rc;
int ni_count;
- struct lnet_ping_info *pinfo;
- struct lnet_handle_md md_handle;
+ struct lnet_ping_buffer *pbuf;
+ struct lnet_handle_md ping_mdh;
struct list_head net_head;
struct lnet_net *net;
the_lnet.ln_refcount = 1;
/* Now I may use my own API functions... */
- rc = lnet_ping_info_setup(&pinfo, &md_handle, ni_count, true);
+ rc = lnet_ping_target_setup(&pbuf, &ping_mdh, ni_count, true);
if (rc != 0)
goto err_acceptor_stop;
- lnet_ping_target_update(pinfo, md_handle);
+ lnet_ping_target_update(pbuf, ping_mdh);
rc = lnet_router_checker_start();
if (rc != 0)
}
cfg_ni->lic_nid = ni->ni_nid;
- cfg_ni->lic_status = ni->ni_status->ns_status;
+ if (LNET_NETTYP(LNET_NIDNET(ni->ni_nid)) == LOLND)
+ cfg_ni->lic_status = LNET_NI_STATUS_UP;
+ else
+ cfg_ni->lic_status = ni->ni_status->ns_status;
cfg_ni->lic_tcp_bonding = use_tcp_bonding;
cfg_ni->lic_dev_cpt = ni->ni_dev_cpt;
config->cfg_config_u.cfg_net.net_peer_rtr_credits =
ni->ni_net->net_tunables.lct_peer_rtr_credits;
- net_config->ni_status = ni->ni_status->ns_status;
+ if (LNET_NETTYP(LNET_NIDNET(ni->ni_nid)) == LOLND)
+ net_config->ni_status = LNET_NI_STATUS_UP;
+ else
+ net_config->ni_status = ni->ni_status->ns_status;
if (ni->ni_cpts) {
int num_cpts = min(ni->ni_ncpts, LNET_MAX_SHOW_NUM_CPT);
struct lnet_ioctl_config_lnd_tunables *tun)
{
__u32 net_id;
- struct lnet_ping_info *pinfo;
- struct lnet_handle_md md_handle;
+ struct lnet_ping_buffer *pbuf;
+ struct lnet_handle_md ping_mdh;
int rc;
struct lnet_remotenet *rnet;
int net_ni_count;
/*
* make sure you calculate the correct number of slots in the ping
- * info. Since the ping info is a flattened list of all the NIs,
+ * buffer. Since the ping info is a flattened list of all the NIs,
* we should allocate enough slots to accomodate the number of NIs
* which will be added.
*
*/
net_ni_count = lnet_get_net_ni_count_pre(net);
- rc = lnet_ping_info_setup(&pinfo, &md_handle,
- net_ni_count + lnet_get_ni_count(),
- false);
+ rc = lnet_ping_target_setup(&pbuf, &ping_mdh,
+ net_ni_count + lnet_get_ni_count(),
+ false);
if (rc < 0) {
lnet_net_free(net);
return rc;
lnet_peer_net_added(net);
lnet_net_unlock(LNET_LOCK_EX);
- lnet_ping_target_update(pinfo, md_handle);
+ lnet_ping_target_update(pbuf, ping_mdh);
return 0;
failed:
- lnet_ping_md_unlink(pinfo, &md_handle);
- lnet_ping_info_free(pinfo);
+ lnet_ping_md_unlink(pbuf, &ping_mdh);
+ lnet_ping_buffer_decref(pbuf);
return rc;
}
struct lnet_net *net;
struct lnet_ni *ni;
__u32 net_id = LNET_NIDNET(conf->lic_nid);
- struct lnet_ping_info *pinfo;
- struct lnet_handle_md md_handle;
+ struct lnet_ping_buffer *pbuf;
+ struct lnet_handle_md ping_mdh;
int rc;
int net_count;
__u32 addr;
CERROR("net %s not found\n",
libcfs_net2str(net_id));
rc = -ENOENT;
- goto net_unlock;
+ goto unlock_net;
}
addr = LNET_NIDADDR(conf->lic_nid);
lnet_net_unlock(0);
/* create and link a new ping info, before removing the old one */
- rc = lnet_ping_info_setup(&pinfo, &md_handle,
+ rc = lnet_ping_target_setup(&pbuf, &ping_mdh,
lnet_get_ni_count() - net_count,
false);
if (rc != 0)
- goto out;
+ goto unlock_api_mutex;
lnet_shutdown_lndnet(net);
if (lnet_count_acceptor_nets() == 0)
lnet_acceptor_stop();
- lnet_ping_target_update(pinfo, md_handle);
+ lnet_ping_target_update(pbuf, ping_mdh);
- goto out;
+ goto unlock_api_mutex;
}
ni = lnet_nid2ni_locked(conf->lic_nid, 0);
if (!ni) {
- CERROR("nid %s not found \n",
+ CERROR("nid %s not found\n",
libcfs_nid2str(conf->lic_nid));
rc = -ENOENT;
- goto net_unlock;
+ goto unlock_net;
}
net_count = lnet_get_net_ni_count_locked(net);
lnet_net_unlock(0);
/* create and link a new ping info, before removing the old one */
- rc = lnet_ping_info_setup(&pinfo, &md_handle,
+ rc = lnet_ping_target_setup(&pbuf, &ping_mdh,
lnet_get_ni_count() - 1, false);
if (rc != 0)
- goto out;
+ goto unlock_api_mutex;
lnet_shutdown_lndni(ni);
if (lnet_count_acceptor_nets() == 0)
lnet_acceptor_stop();
- lnet_ping_target_update(pinfo, md_handle);
+ lnet_ping_target_update(pbuf, ping_mdh);
/* check if the net is empty and remove it if it is */
if (net_count == 1)
lnet_shutdown_lndnet(net);
- goto out;
+ goto unlock_api_mutex;
-net_unlock:
+unlock_net:
lnet_net_unlock(0);
-out:
+unlock_api_mutex:
mutex_unlock(&the_lnet.ln_api_mutex);
return rc;
lnet_dyn_del_net(__u32 net_id)
{
struct lnet_net *net;
- struct lnet_ping_info *pinfo;
- struct lnet_handle_md md_handle;
+ struct lnet_ping_buffer *pbuf;
+ struct lnet_handle_md ping_mdh;
int rc;
int net_ni_count;
lnet_net_unlock(0);
/* create and link a new ping info, before removing the old one */
- rc = lnet_ping_info_setup(&pinfo, &md_handle,
- lnet_get_ni_count() - net_ni_count, false);
+ rc = lnet_ping_target_setup(&pbuf, &ping_mdh,
+ lnet_get_ni_count() - net_ni_count, false);
if (rc != 0)
goto out;
if (lnet_count_acceptor_nets() == 0)
lnet_acceptor_stop();
- lnet_ping_target_update(pinfo, md_handle);
+ lnet_ping_target_update(pbuf, ping_mdh);
out:
mutex_unlock(&the_lnet.ln_api_mutex);
int unlinked = 0;
int replied = 0;
const signed long a_long_time = msecs_to_jiffies(60 * MSEC_PER_SEC);
- int infosz;
- struct lnet_ping_info *info;
+ struct lnet_ping_buffer *pbuf;
struct lnet_process_id tmpid;
int i;
int nob;
int rc2;
sigset_t blocked;
- infosz = offsetof(struct lnet_ping_info, pi_ni[n_ids]);
-
/* n_ids limit is arbitrary */
if (n_ids <= 0 || n_ids > lnet_interfaces_max || id.nid == LNET_NID_ANY)
return -EINVAL;
if (id.pid == LNET_PID_ANY)
id.pid = LNET_PID_LUSTRE;
- LIBCFS_ALLOC(info, infosz);
- if (info == NULL)
+ pbuf = lnet_ping_buffer_alloc(n_ids, GFP_NOFS);
+ if (!pbuf)
return -ENOMEM;
/* NB 2 events max (including any unlink event) */
rc = LNetEQAlloc(2, LNET_EQ_HANDLER_NONE, &eqh);
if (rc != 0) {
CERROR("Can't allocate EQ: %d\n", rc);
- goto out_0;
+ goto fail_ping_buffer_decref;
}
/* initialize md content */
- md.start = info;
- md.length = infosz;
+ md.start = &pbuf->pb_info;
+ md.length = LNET_PING_INFO_SIZE(n_ids);
md.threshold = 2; /*GET/REPLY*/
md.max_size = 0;
md.options = LNET_MD_TRUNCATE;
rc = LNetMDBind(md, LNET_UNLINK, &mdh);
if (rc != 0) {
CERROR("Can't bind MD: %d\n", rc);
- goto out_1;
+ goto fail_free_eq;
}
rc = LNetGet(LNET_NID_ANY, mdh, id,
CWARN("%s: Unexpected rc >= 0 but no reply!\n",
libcfs_id2str(id));
rc = -EIO;
- goto out_1;
+ goto fail_free_eq;
}
nob = rc;
- LASSERT(nob >= 0 && nob <= infosz);
+ LASSERT(nob >= 0 && nob <= LNET_PING_INFO_SIZE(n_ids));
rc = -EPROTO; /* if I can't parse... */
/* can't check magic/version */
CERROR("%s: ping info too short %d\n",
libcfs_id2str(id), nob);
- goto out_1;
+ goto fail_free_eq;
}
- if (info->pi_magic == __swab32(LNET_PROTO_PING_MAGIC)) {
- lnet_swap_pinginfo(info);
- } else if (info->pi_magic != LNET_PROTO_PING_MAGIC) {
+ if (pbuf->pb_info.pi_magic == __swab32(LNET_PROTO_PING_MAGIC)) {
+ lnet_swap_pinginfo(pbuf);
+ } else if (pbuf->pb_info.pi_magic != LNET_PROTO_PING_MAGIC) {
CERROR("%s: Unexpected magic %08x\n",
- libcfs_id2str(id), info->pi_magic);
- goto out_1;
+ libcfs_id2str(id), pbuf->pb_info.pi_magic);
+ goto fail_free_eq;
}
- if ((info->pi_features & LNET_PING_FEAT_NI_STATUS) == 0) {
+ if ((pbuf->pb_info.pi_features & LNET_PING_FEAT_NI_STATUS) == 0) {
CERROR("%s: ping w/o NI status: 0x%x\n",
- libcfs_id2str(id), info->pi_features);
- goto out_1;
+ libcfs_id2str(id), pbuf->pb_info.pi_features);
+ goto fail_free_eq;
}
- if (nob < offsetof(struct lnet_ping_info, pi_ni[0])) {
+ if (nob < LNET_PING_INFO_SIZE(0)) {
CERROR("%s: Short reply %d(%d min)\n", libcfs_id2str(id),
- nob, (int)offsetof(struct lnet_ping_info, pi_ni[0]));
- goto out_1;
+ nob, (int)LNET_PING_INFO_SIZE(0));
+ goto fail_free_eq;
}
- if (info->pi_nnis < n_ids)
- n_ids = info->pi_nnis;
+ if (pbuf->pb_info.pi_nnis < n_ids)
+ n_ids = pbuf->pb_info.pi_nnis;
- if (nob < offsetof(struct lnet_ping_info, pi_ni[n_ids])) {
+ if (nob < LNET_PING_INFO_SIZE(n_ids)) {
CERROR("%s: Short reply %d(%d expected)\n", libcfs_id2str(id),
- nob, (int)offsetof(struct lnet_ping_info, pi_ni[n_ids]));
- goto out_1;
+ nob, (int)LNET_PING_INFO_SIZE(n_ids));
+ goto fail_free_eq;
}
rc = -EFAULT; /* If I SEGV... */
memset(&tmpid, 0, sizeof(tmpid));
for (i = 0; i < n_ids; i++) {
- tmpid.pid = info->pi_pid;
- tmpid.nid = info->pi_ni[i].ns_nid;
+ tmpid.pid = pbuf->pb_info.pi_pid;
+ tmpid.nid = pbuf->pb_info.pi_ni[i].ns_nid;
if (copy_to_user(&ids[i], &tmpid, sizeof(tmpid)))
- goto out_1;
+ goto fail_free_eq;
}
- rc = info->pi_nnis;
+ rc = pbuf->pb_info.pi_nnis;
- out_1:
+ fail_free_eq:
rc2 = LNetEQFree(eqh);
if (rc2 != 0)
CERROR("rc2 %d\n", rc2);
LASSERT(rc2 == 0);
- out_0:
- LIBCFS_FREE(info, infosz);
+ fail_ping_buffer_decref:
+ lnet_ping_buffer_decref(pbuf);
return rc;
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff