* [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer
@ 2021-03-04 19:56 Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 1/8] fs: dlm: public header in out utility Alexander Aring
` (7 more replies)
0 siblings, 8 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
Hi,
this is the final patch-series to make dlm reliable when re-connection
occurs. You can easily generate a couple of re-connections by running:
tcpkill -9 -i $IFACE port 21064
on your own to test these patches. At some time dlm will detect message
drops and will re-transmit messages if necessary. It introduces a new dlm
protocol behaviour and increases the dlm protocol version. I tested it
with SCTP as well and tried to be backwards compatible with dlm protocol
version 3.1. However I don't recommend at all to mix these versions
in a setup since dlm version 3.2 fixes long-term issues.
- Alex
changes since patch series split:
- fixup "fs: dlm: make new buffer handling softirq ready" into
"fs: dlm: add functionality to re-transmit a message"
- change hooks to work with shutdown hook
- use DEFAULT_BUFFER_SIZE for max send/recv buffer, because
backwards compatiblility with dlm 3.1
- remove "fs: dlm: add per node receive flush", I think we don't
run into issues.
- change comments regarding why DLM_FIN is needed.
- move midcomms_remove_member hook in dlm protocol when removing
ls->nodes_gone list, so far I can see it's the last point
that the lockspace has this node as a member in some datastructures.
- make deep free of recv/send queue when midcomms_node is freed
- add DLM_NODE_FLAG_STOP_TX flag for midcomms node to warn
if a node tries to send at point where dlm application should
not starting transmissions anymore. It indicates a bug.
- change some retransmit/timeout timings, I think we need somehow to
figure out by waiting e.g. user reports if we getting problems with
them.
Alexander Aring (8):
fs: dlm: public header in out utility
fs: dlm: add more midcomms hooks
fs: dlm: make buffer handling per msg
fs: dlm: add functionality to re-transmit a message
fs: dlm: move out some hash functionality
fs: dlm: add union in dlm header for lockspace id
fs: dlm: add reliable connection if reconnect
fs: dlm: don't allow half transmitted messages
fs/dlm/config.c | 3 +-
fs/dlm/dlm_internal.h | 35 +-
fs/dlm/lock.c | 14 +-
fs/dlm/lockspace.c | 14 +-
fs/dlm/lowcomms.c | 197 +++++--
fs/dlm/lowcomms.h | 23 +-
fs/dlm/member.c | 12 +-
fs/dlm/midcomms.c | 1281 ++++++++++++++++++++++++++++++++++++++++-
fs/dlm/midcomms.h | 10 +
fs/dlm/rcom.c | 63 +-
fs/dlm/recoverd.c | 1 +
fs/dlm/util.c | 10 +-
fs/dlm/util.h | 2 +
13 files changed, 1552 insertions(+), 113 deletions(-)
--
2.26.2
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 1/8] fs: dlm: public header in out utility
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 2/8] fs: dlm: add more midcomms hooks Alexander Aring
` (6 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch allows to use header_out() and header_in() outside of dlm
util functionality.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/util.c | 4 ++--
fs/dlm/util.h | 2 ++
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/dlm/util.c b/fs/dlm/util.c
index cfd0d00b19ae..74a8c5bfe9b5 100644
--- a/fs/dlm/util.c
+++ b/fs/dlm/util.c
@@ -20,7 +20,7 @@
#define DLM_ERRNO_ETIMEDOUT 110
#define DLM_ERRNO_EINPROGRESS 115
-static void header_out(struct dlm_header *hd)
+void header_out(struct dlm_header *hd)
{
hd->h_version = cpu_to_le32(hd->h_version);
hd->h_lockspace = cpu_to_le32(hd->h_lockspace);
@@ -28,7 +28,7 @@ static void header_out(struct dlm_header *hd)
hd->h_length = cpu_to_le16(hd->h_length);
}
-static void header_in(struct dlm_header *hd)
+void header_in(struct dlm_header *hd)
{
hd->h_version = le32_to_cpu(hd->h_version);
hd->h_lockspace = le32_to_cpu(hd->h_lockspace);
diff --git a/fs/dlm/util.h b/fs/dlm/util.h
index cc719ca9397e..d46f23c7a6a0 100644
--- a/fs/dlm/util.h
+++ b/fs/dlm/util.h
@@ -15,6 +15,8 @@ void dlm_message_out(struct dlm_message *ms);
void dlm_message_in(struct dlm_message *ms);
void dlm_rcom_out(struct dlm_rcom *rc);
void dlm_rcom_in(struct dlm_rcom *rc);
+void header_out(struct dlm_header *hd);
+void header_in(struct dlm_header *hd);
#endif
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 2/8] fs: dlm: add more midcomms hooks
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 1/8] fs: dlm: public header in out utility Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 3/8] fs: dlm: make buffer handling per msg Alexander Aring
` (5 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch prepares hooks to redirect to the midcomms layer which will
be used by the midcomms re-transmit handling.
There exists the new concept of stateless buffers allocation and
commits. This can be used to bypass the midcomms re-transmit handling. It
is used by RCOM_STATUS and RCOM_NAMES messages, because they have their
own ping-like re-transmit handling. As well these two messages will be
used to determine the DLM version per node, because these two messages
are per observation the first messages which are exchanged.
The midcomms_remove_member() hook should be called when there is nothing
to send to the other node and the other node is still capable to
transmit dlm messages to the other node which called
midcomms_remove_member(). I experienced that the dlm protocol has a lack
of support for synchronize this event on protocol level. The result was
that there was still something to transmit but the other node was already
gone. This hook can be used to provide such synchronization. Although I
am not totally sure about the placement of this hook, I did not observed
issues yet when providing such synchronization on protocol layer.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/config.c | 3 ++-
fs/dlm/lock.c | 6 ++---
fs/dlm/lockspace.c | 7 +++---
fs/dlm/member.c | 12 +++++++++-
fs/dlm/midcomms.c | 44 +++++++++++++++++++++++++++++++++++++
fs/dlm/midcomms.h | 10 +++++++++
fs/dlm/rcom.c | 55 +++++++++++++++++++++++++++-------------------
fs/dlm/recoverd.c | 1 +
8 files changed, 108 insertions(+), 30 deletions(-)
diff --git a/fs/dlm/config.c b/fs/dlm/config.c
index 88d95d96e36c..01ae294743e9 100644
--- a/fs/dlm/config.c
+++ b/fs/dlm/config.c
@@ -20,6 +20,7 @@
#include <net/sock.h>
#include "config.h"
+#include "midcomms.h"
#include "lowcomms.h"
/*
@@ -532,7 +533,7 @@ static void drop_comm(struct config_group *g, struct config_item *i)
struct dlm_comm *cm = config_item_to_comm(i);
if (local_comm == cm)
local_comm = NULL;
- dlm_lowcomms_close(cm->nodeid);
+ dlm_midcomms_close(cm->nodeid);
while (cm->addr_count--)
kfree(cm->addr[cm->addr_count]);
config_item_put(i);
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index b93df39d0915..b3fd823009f4 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -59,7 +59,7 @@
#include "dlm_internal.h"
#include <linux/dlm_device.h>
#include "memory.h"
-#include "lowcomms.h"
+#include "midcomms.h"
#include "requestqueue.h"
#include "util.h"
#include "dir.h"
@@ -3537,7 +3537,7 @@ static int _create_message(struct dlm_ls *ls, int mb_len,
pass into lowcomms_commit and a message buffer (mb) that we
write our data into */
- mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, GFP_NOFS, &mb);
+ mh = dlm_midcomms_get_buffer(to_nodeid, mb_len, GFP_NOFS, &mb);
if (!mh)
return -ENOBUFS;
@@ -3589,7 +3589,7 @@ static int create_message(struct dlm_rsb *r, struct dlm_lkb *lkb,
static int send_message(struct dlm_mhandle *mh, struct dlm_message *ms)
{
dlm_message_out(ms);
- dlm_lowcomms_commit_buffer(mh);
+ dlm_midcomms_commit_buffer(mh);
return 0;
}
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index c14cf2b7faab..bf5c55ef9d0d 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -16,6 +16,7 @@
#include "member.h"
#include "recoverd.h"
#include "dir.h"
+#include "midcomms.h"
#include "lowcomms.h"
#include "config.h"
#include "memory.h"
@@ -390,7 +391,7 @@ static int threads_start(void)
}
/* Thread for sending/receiving messages for all lockspace's */
- error = dlm_lowcomms_start();
+ error = dlm_midcomms_start();
if (error) {
log_print("cannot start dlm lowcomms %d", error);
goto scand_fail;
@@ -698,7 +699,7 @@ int dlm_new_lockspace(const char *name, const char *cluster,
error = 0;
if (!ls_count) {
dlm_scand_stop();
- dlm_lowcomms_shutdown();
+ dlm_midcomms_shutdown();
dlm_lowcomms_stop();
}
out:
@@ -787,7 +788,7 @@ static int release_lockspace(struct dlm_ls *ls, int force)
if (ls_count == 1) {
dlm_scand_stop();
- dlm_lowcomms_shutdown();
+ dlm_midcomms_shutdown();
}
dlm_callback_stop(ls);
diff --git a/fs/dlm/member.c b/fs/dlm/member.c
index ceef3f2074ff..c018a995a8ab 100644
--- a/fs/dlm/member.c
+++ b/fs/dlm/member.c
@@ -15,6 +15,7 @@
#include "recover.h"
#include "rcom.h"
#include "config.h"
+#include "midcomms.h"
#include "lowcomms.h"
int dlm_slots_version(struct dlm_header *h)
@@ -378,7 +379,15 @@ void dlm_clear_members(struct dlm_ls *ls)
void dlm_clear_members_gone(struct dlm_ls *ls)
{
- clear_memb_list(&ls->ls_nodes_gone);
+ struct list_head *head = &ls->ls_nodes_gone;
+ struct dlm_member *memb;
+
+ while (!list_empty(head)) {
+ memb = list_entry(head->next, struct dlm_member, list);
+ midcomms_remove_member(memb->nodeid);
+ list_del(&memb->list);
+ kfree(memb);
+ }
}
static void make_member_array(struct dlm_ls *ls)
@@ -563,6 +572,7 @@ int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
if (dlm_is_member(ls, node->nodeid))
continue;
dlm_add_member(ls, node);
+ midcomms_add_member(node->nodeid);
log_rinfo(ls, "add member %d", node->nodeid);
}
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index 1c6654a21ec4..bbcb242e6101 100644
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -28,6 +28,50 @@
#include "lock.h"
#include "midcomms.h"
+void *dlm_midcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
+{
+ return dlm_lowcomms_get_buffer(nodeid, len, allocation, ppc);
+}
+
+void dlm_midcomms_commit_buffer(void *mh)
+{
+ dlm_lowcomms_commit_buffer(mh);
+}
+
+void *dlm_midcomms_stateless_get_buffer(int nodeid, int len, gfp_t allocation,
+ char **ppc)
+{
+ return dlm_lowcomms_get_buffer(nodeid, len, allocation, ppc);
+}
+
+void dlm_midcomms_stateless_commit_buffer(void *mh)
+{
+ dlm_lowcomms_commit_buffer(mh);
+}
+
+void midcomms_add_member(int nodeid)
+{
+}
+
+void midcomms_remove_member(int nodeid)
+{
+}
+
+int dlm_midcomms_close(int nodeid)
+{
+ return dlm_lowcomms_close(nodeid);
+}
+
+int dlm_midcomms_start(void)
+{
+ return dlm_lowcomms_start();
+}
+
+void dlm_midcomms_shutdown(void)
+{
+ dlm_lowcomms_shutdown();
+}
+
/*
* Called from the low-level comms layer to process a buffer of
* commands.
diff --git a/fs/dlm/midcomms.h b/fs/dlm/midcomms.h
index 61e90a921849..6ce2f2947475 100644
--- a/fs/dlm/midcomms.h
+++ b/fs/dlm/midcomms.h
@@ -13,6 +13,16 @@
#define __MIDCOMMS_DOT_H__
int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int buflen);
+void *dlm_midcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc);
+void dlm_midcomms_commit_buffer(void *mh);
+void *dlm_midcomms_stateless_get_buffer(int nodeid, int len, gfp_t allocation,
+ char **ppc);
+void dlm_midcomms_stateless_commit_buffer(void *mh);
+void midcomms_add_member(int nodeid);
+void midcomms_remove_member(int nodeid);
+int dlm_midcomms_close(int nodeid);
+int dlm_midcomms_start(void);
+void dlm_midcomms_shutdown(void);
#endif /* __MIDCOMMS_DOT_H__ */
diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index f5b1bd65728d..7a7d4a8e4706 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -28,14 +28,18 @@ static int rcom_response(struct dlm_ls *ls)
}
static int create_rcom(struct dlm_ls *ls, int to_nodeid, int type, int len,
- struct dlm_rcom **rc_ret, struct dlm_mhandle **mh_ret)
+ struct dlm_rcom **rc_ret, struct dlm_mhandle **mh_ret,
+ bool stateless)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
char *mb;
int mb_len = sizeof(struct dlm_rcom) + len;
- mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, GFP_NOFS, &mb);
+ if (stateless)
+ mh = dlm_midcomms_stateless_get_buffer(to_nodeid, mb_len, GFP_NOFS, &mb);
+ else
+ mh = dlm_midcomms_get_buffer(to_nodeid, mb_len, GFP_NOFS, &mb);
if (!mh) {
log_print("create_rcom to %d type %d len %d ENOBUFS",
to_nodeid, type, len);
@@ -62,10 +66,13 @@ static int create_rcom(struct dlm_ls *ls, int to_nodeid, int type, int len,
}
static void send_rcom(struct dlm_ls *ls, struct dlm_mhandle *mh,
- struct dlm_rcom *rc)
+ struct dlm_rcom *rc, bool stateless)
{
dlm_rcom_out(rc);
- dlm_lowcomms_commit_buffer(mh);
+ if (stateless)
+ dlm_midcomms_stateless_commit_buffer(mh);
+ else
+ dlm_midcomms_commit_buffer(mh);
}
static void set_rcom_status(struct dlm_ls *ls, struct rcom_status *rs,
@@ -154,7 +161,7 @@ int dlm_rcom_status(struct dlm_ls *ls, int nodeid, uint32_t status_flags)
retry:
error = create_rcom(ls, nodeid, DLM_RCOM_STATUS,
- sizeof(struct rcom_status), &rc, &mh);
+ sizeof(struct rcom_status), &rc, &mh, true);
if (error)
goto out;
@@ -163,7 +170,7 @@ int dlm_rcom_status(struct dlm_ls *ls, int nodeid, uint32_t status_flags)
allow_sync_reply(ls, &rc->rc_id);
memset(ls->ls_recover_buf, 0, LOWCOMMS_MAX_TX_BUFFER_LEN);
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, true);
error = dlm_wait_function(ls, &rcom_response);
disallow_sync_reply(ls);
@@ -219,7 +226,7 @@ static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
do_create:
error = create_rcom(ls, nodeid, DLM_RCOM_STATUS_REPLY,
- len, &rc, &mh);
+ len, &rc, &mh, true);
if (error)
return;
@@ -246,7 +253,7 @@ static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
spin_unlock(&ls->ls_recover_lock);
do_send:
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, true);
}
static void receive_sync_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
@@ -277,7 +284,8 @@ int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
ls->ls_recover_nodeid = nodeid;
retry:
- error = create_rcom(ls, nodeid, DLM_RCOM_NAMES, last_len, &rc, &mh);
+ error = create_rcom(ls, nodeid, DLM_RCOM_NAMES, last_len, &rc, &mh,
+ true);
if (error)
goto out;
memcpy(rc->rc_buf, last_name, last_len);
@@ -285,7 +293,7 @@ int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
allow_sync_reply(ls, &rc->rc_id);
memset(ls->ls_recover_buf, 0, LOWCOMMS_MAX_TX_BUFFER_LEN);
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, true);
error = dlm_wait_function(ls, &rcom_response);
disallow_sync_reply(ls);
@@ -305,7 +313,8 @@ static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
inlen = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
outlen = LOWCOMMS_MAX_TX_BUFFER_LEN - sizeof(struct dlm_rcom);
- error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh);
+ error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh,
+ true);
if (error)
return;
rc->rc_id = rc_in->rc_id;
@@ -313,7 +322,7 @@ static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
dlm_copy_master_names(ls, rc_in->rc_buf, inlen, rc->rc_buf, outlen,
nodeid);
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, true);
}
int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)
@@ -324,13 +333,13 @@ int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)
int error;
error = create_rcom(ls, dir_nodeid, DLM_RCOM_LOOKUP, r->res_length,
- &rc, &mh);
+ &rc, &mh, false);
if (error)
goto out;
memcpy(rc->rc_buf, r->res_name, r->res_length);
rc->rc_id = (unsigned long) r->res_id;
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, false);
out:
return error;
}
@@ -342,7 +351,8 @@ static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
int error, ret_nodeid, nodeid = rc_in->rc_header.h_nodeid;
int len = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
- error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh);
+ error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh,
+ false);
if (error)
return;
@@ -361,7 +371,7 @@ static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
rc->rc_id = rc_in->rc_id;
rc->rc_seq_reply = rc_in->rc_seq;
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, false);
}
static void receive_rcom_lookup_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
@@ -410,7 +420,8 @@ int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
if (lkb->lkb_lvbptr)
len += ls->ls_lvblen;
- error = create_rcom(ls, r->res_nodeid, DLM_RCOM_LOCK, len, &rc, &mh);
+ error = create_rcom(ls, r->res_nodeid, DLM_RCOM_LOCK, len, &rc, &mh,
+ false);
if (error)
goto out;
@@ -418,7 +429,7 @@ int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
pack_rcom_lock(r, lkb, rl);
rc->rc_id = (unsigned long) r;
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, false);
out:
return error;
}
@@ -433,7 +444,7 @@ static void receive_rcom_lock(struct dlm_ls *ls, struct dlm_rcom *rc_in)
dlm_recover_master_copy(ls, rc_in);
error = create_rcom(ls, nodeid, DLM_RCOM_LOCK_REPLY,
- sizeof(struct rcom_lock), &rc, &mh);
+ sizeof(struct rcom_lock), &rc, &mh, false);
if (error)
return;
@@ -444,7 +455,7 @@ static void receive_rcom_lock(struct dlm_ls *ls, struct dlm_rcom *rc_in)
rc->rc_id = rc_in->rc_id;
rc->rc_seq_reply = rc_in->rc_seq;
- send_rcom(ls, mh, rc);
+ send_rcom(ls, mh, rc, false);
}
/* If the lockspace doesn't exist then still send a status message
@@ -458,7 +469,7 @@ int dlm_send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
char *mb;
int mb_len = sizeof(struct dlm_rcom) + sizeof(struct rcom_config);
- mh = dlm_lowcomms_get_buffer(nodeid, mb_len, GFP_NOFS, &mb);
+ mh = dlm_midcomms_get_buffer(nodeid, mb_len, GFP_NOFS, &mb);
if (!mh)
return -ENOBUFS;
@@ -479,7 +490,7 @@ int dlm_send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
rf->rf_lvblen = cpu_to_le32(~0U);
dlm_rcom_out(rc);
- dlm_lowcomms_commit_buffer(mh);
+ dlm_midcomms_commit_buffer(mh);
return 0;
}
diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index 85e245392715..81beca11c2e8 100644
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -16,6 +16,7 @@
#include "ast.h"
#include "recover.h"
#include "lowcomms.h"
+#include "midcomms.h"
#include "lock.h"
#include "requestqueue.h"
#include "recoverd.h"
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 3/8] fs: dlm: make buffer handling per msg
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 1/8] fs: dlm: public header in out utility Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 2/8] fs: dlm: add more midcomms hooks Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 4/8] fs: dlm: add functionality to re-transmit a message Alexander Aring
` (4 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch makes the void pointer handle for lowcomms functionality per
message and not per page allocation entry. A refcount handling for the
handle was added to keep the message alive until the user doesn't need
it anymore.
There exists now a per message callback which will be called when
allocating a new buffer. This callback will be guaranteed to be called
according the order of the sending buffer, which can be used that the
caller increments a sequence number.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/lowcomms.c | 100 +++++++++++++++++++++++++++++++++++++++++-----
fs/dlm/lowcomms.h | 5 ++-
fs/dlm/midcomms.c | 8 +++-
3 files changed, 101 insertions(+), 12 deletions(-)
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 73cc1809050a..ba782ea84281 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -114,6 +114,17 @@ struct writequeue_entry {
int end;
int users;
struct connection *con;
+ struct list_head msgs;
+ struct kref ref;
+};
+
+struct dlm_msg {
+ struct writequeue_entry *entry;
+ void *ppc;
+ int len;
+
+ struct list_head list;
+ struct kref ref;
};
struct dlm_node_addr {
@@ -976,12 +987,36 @@ static int accept_from_sock(struct listen_connection *con)
return result;
}
-static void free_entry(struct writequeue_entry *e)
+static void dlm_page_release(struct kref *kref)
{
+ struct writequeue_entry *e = container_of(kref, struct writequeue_entry,
+ ref);
+
__free_page(e->page);
kfree(e);
}
+static void dlm_msg_release(struct kref *kref)
+{
+ struct dlm_msg *msg = container_of(kref, struct dlm_msg, ref);
+
+ kref_put(&msg->entry->ref, dlm_page_release);
+ kfree(msg);
+}
+
+static void free_entry(struct writequeue_entry *e)
+{
+ struct dlm_msg *msg, *tmp;
+
+ list_for_each_entry_safe(msg, tmp, &e->msgs, list) {
+ list_del(&msg->list);
+ kref_put(&msg->ref, dlm_msg_release);
+ }
+
+ list_del(&e->list);
+ kref_put(&e->ref, dlm_page_release);
+}
+
/*
* writequeue_entry_complete - try to delete and free write queue entry
* @e: write queue entry to try to delete
@@ -994,10 +1029,8 @@ static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
e->offset += completed;
e->len -= completed;
- if (e->len == 0 && e->users == 0) {
- list_del(&e->list);
+ if (e->len == 0 && e->users == 0)
free_entry(e);
- }
}
/*
@@ -1363,12 +1396,16 @@ static struct writequeue_entry *new_writequeue_entry(struct connection *con,
entry->con = con;
entry->users = 1;
+ kref_init(&entry->ref);
+ INIT_LIST_HEAD(&entry->msgs);
return entry;
}
static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
- gfp_t allocation, char **ppc)
+ gfp_t allocation, char **ppc,
+ void (*cb)(void *buf, void *priv),
+ void *priv)
{
struct writequeue_entry *e;
@@ -1376,7 +1413,12 @@ static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
if (!list_empty(&con->writequeue)) {
e = list_last_entry(&con->writequeue, struct writequeue_entry, list);
if (DLM_WQ_REMAIN_BYTES(e) >= len) {
+ kref_get(&e->ref);
+
*ppc = page_address(e->page) + e->end;
+ if (cb)
+ cb(*ppc, priv);
+
e->end += len;
e->users++;
spin_unlock(&con->writequeue_lock);
@@ -1390,19 +1432,26 @@ static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
if (!e)
return NULL;
+ kref_get(&e->ref);
*ppc = page_address(e->page);
e->end += len;
spin_lock(&con->writequeue_lock);
+ if (cb)
+ cb(*ppc, priv);
+
list_add_tail(&e->list, &con->writequeue);
spin_unlock(&con->writequeue_lock);
return e;
};
-void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
+void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
+ void (*cb)(void *buf, void *priv), void *priv)
{
+ struct writequeue_entry *e;
struct connection *con;
+ struct dlm_msg *msg;
if (len > DEFAULT_BUFFER_SIZE ||
len < sizeof(struct dlm_header)) {
@@ -1416,16 +1465,36 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
if (!con)
return NULL;
- return new_wq_entry(con, len, allocation, ppc);
+ msg = kzalloc(sizeof(*msg), allocation);
+ if (!msg)
+ return NULL;
+
+ kref_init(&msg->ref);
+
+ e = new_wq_entry(con, len, allocation, ppc, cb, priv);
+ if (!e) {
+ kfree(msg);
+ return NULL;
+ }
+
+ msg->ppc = *ppc;
+ msg->len = len;
+ msg->entry = e;
+
+ return msg;
}
void dlm_lowcomms_commit_buffer(void *mh)
{
- struct writequeue_entry *e = (struct writequeue_entry *)mh;
+ struct dlm_msg *msg = mh;
+ struct writequeue_entry *e = msg->entry;
struct connection *con = e->con;
int users;
spin_lock(&con->writequeue_lock);
+ list_add(&msg->list, &e->msgs);
+ kref_get(&msg->ref);
+
users = --e->users;
if (users)
goto out;
@@ -1441,6 +1510,20 @@ void dlm_lowcomms_commit_buffer(void *mh)
return;
}
+void dlm_lowcomms_put_buffer(void *mh)
+{
+ struct dlm_msg *msg = mh;
+
+ kref_put(&msg->ref, dlm_msg_release);
+}
+
+void dlm_lowcomms_get_buffer(void *mh)
+{
+ struct dlm_msg *msg = mh;
+
+ kref_get(&msg->ref);
+}
+
/* Send a message */
static void send_to_sock(struct connection *con)
{
@@ -1519,7 +1602,6 @@ static void clean_one_writequeue(struct connection *con)
spin_lock(&con->writequeue_lock);
list_for_each_entry_safe(e, safe, &con->writequeue, list) {
- list_del(&e->list);
free_entry(e);
}
spin_unlock(&con->writequeue_lock);
diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h
index 48bbc4e18761..fa735497dad8 100644
--- a/fs/dlm/lowcomms.h
+++ b/fs/dlm/lowcomms.h
@@ -22,11 +22,14 @@ void dlm_lowcomms_shutdown(void);
void dlm_lowcomms_stop(void);
void dlm_lowcomms_exit(void);
int dlm_lowcomms_close(int nodeid);
-void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc);
+void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
+ void (*cb)(void *buf, void *priv), void *priv);
void dlm_lowcomms_commit_buffer(void *mh);
int dlm_lowcomms_connect_node(int nodeid);
int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark);
int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len);
+void dlm_lowcomms_put_buffer(void *mh);
+void dlm_lowcomms_get_buffer(void *mh);
#endif /* __LOWCOMMS_DOT_H__ */
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index bbcb242e6101..2ea0449a82ab 100644
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -30,23 +30,27 @@
void *dlm_midcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
{
- return dlm_lowcomms_get_buffer(nodeid, len, allocation, ppc);
+ return dlm_lowcomms_new_buffer(nodeid, len, allocation, ppc, NULL,
+ NULL);
}
void dlm_midcomms_commit_buffer(void *mh)
{
dlm_lowcomms_commit_buffer(mh);
+ dlm_lowcomms_put_buffer(mh);
}
void *dlm_midcomms_stateless_get_buffer(int nodeid, int len, gfp_t allocation,
char **ppc)
{
- return dlm_lowcomms_get_buffer(nodeid, len, allocation, ppc);
+ return dlm_lowcomms_new_buffer(nodeid, len, allocation, ppc, NULL,
+ NULL);
}
void dlm_midcomms_stateless_commit_buffer(void *mh)
{
dlm_lowcomms_commit_buffer(mh);
+ dlm_lowcomms_put_buffer(mh);
}
void midcomms_add_member(int nodeid)
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 4/8] fs: dlm: add functionality to re-transmit a message
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
` (2 preceding siblings ...)
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 3/8] fs: dlm: make buffer handling per msg Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 5/8] fs: dlm: move out some hash functionality Alexander Aring
` (3 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch introduces a irqsafe retransmit functionality for a lowcomms
message handle. It's just allocates a new buffer and transmit it again,
no special handling about prioritize it because keeping bytestream in
order.
To avoid another connection look some refactor was done to make a new
buffer allocation with a preexisting connection pointer.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/lowcomms.c | 84 +++++++++++++++++++++++++++++++----------------
fs/dlm/lowcomms.h | 1 +
2 files changed, 56 insertions(+), 29 deletions(-)
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index ba782ea84281..d2be58496fd0 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1409,7 +1409,7 @@ static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
{
struct writequeue_entry *e;
- spin_lock(&con->writequeue_lock);
+ spin_lock_bh(&con->writequeue_lock);
if (!list_empty(&con->writequeue)) {
e = list_last_entry(&con->writequeue, struct writequeue_entry, list);
if (DLM_WQ_REMAIN_BYTES(e) >= len) {
@@ -1421,12 +1421,12 @@ static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
e->end += len;
e->users++;
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
return e;
}
}
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
e = new_writequeue_entry(con, allocation);
if (!e)
@@ -1436,35 +1436,24 @@ static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
*ppc = page_address(e->page);
e->end += len;
- spin_lock(&con->writequeue_lock);
+ spin_lock_bh(&con->writequeue_lock);
if (cb)
cb(*ppc, priv);
list_add_tail(&e->list, &con->writequeue);
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
return e;
};
-void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
- void (*cb)(void *buf, void *priv), void *priv)
+static void *dlm_lowcomms_new_buffer_con(struct connection *con, int len,
+ gfp_t allocation, char **ppc,
+ void (*cb)(void *buf, void *priv),
+ void *priv)
{
struct writequeue_entry *e;
- struct connection *con;
struct dlm_msg *msg;
- if (len > DEFAULT_BUFFER_SIZE ||
- len < sizeof(struct dlm_header)) {
- BUILD_BUG_ON(PAGE_SIZE < DEFAULT_BUFFER_SIZE);
- log_print("failed to allocate a buffer of size %d", len);
- WARN_ON(1);
- return NULL;
- }
-
- con = nodeid2con(nodeid, allocation);
- if (!con)
- return NULL;
-
msg = kzalloc(sizeof(*msg), allocation);
if (!msg)
return NULL;
@@ -1484,6 +1473,26 @@ void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
return msg;
}
+void *dlm_lowcomms_new_buffer(int nodeid, int len, gfp_t allocation, char **ppc,
+ void (*cb)(void *buf, void *priv), void *priv)
+{
+ struct connection *con;
+
+ if (len > DEFAULT_BUFFER_SIZE ||
+ len < sizeof(struct dlm_header)) {
+ BUILD_BUG_ON(PAGE_SIZE < DEFAULT_BUFFER_SIZE);
+ log_print("failed to allocate a buffer of size %d", len);
+ WARN_ON(1);
+ return NULL;
+ }
+
+ con = nodeid2con(nodeid, allocation);
+ if (!con)
+ return NULL;
+
+ return dlm_lowcomms_new_buffer_con(con, len, GFP_ATOMIC, ppc, cb, priv);
+}
+
void dlm_lowcomms_commit_buffer(void *mh)
{
struct dlm_msg *msg = mh;
@@ -1491,7 +1500,7 @@ void dlm_lowcomms_commit_buffer(void *mh)
struct connection *con = e->con;
int users;
- spin_lock(&con->writequeue_lock);
+ spin_lock_bh(&con->writequeue_lock);
list_add(&msg->list, &e->msgs);
kref_get(&msg->ref);
@@ -1500,13 +1509,13 @@ void dlm_lowcomms_commit_buffer(void *mh)
goto out;
e->len = DLM_WQ_LENGTH_BYTES(e);
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
queue_work(send_workqueue, &con->swork);
return;
out:
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
return;
}
@@ -1524,6 +1533,23 @@ void dlm_lowcomms_get_buffer(void *mh)
kref_get(&msg->ref);
}
+/* irqsafe */
+void dlm_lowcomms_resend_buffer(void *mh)
+{
+ struct dlm_msg *msg = mh;
+ void *mh_new;
+ char *ppc;
+
+ mh_new = dlm_lowcomms_new_buffer_con(msg->entry->con, msg->len, GFP_ATOMIC,
+ &ppc, NULL, NULL);
+ if (!mh_new)
+ return;
+
+ memcpy(ppc, msg->ppc, msg->len);
+ dlm_lowcomms_commit_buffer(mh_new);
+ dlm_lowcomms_put_buffer(mh_new);
+}
+
/* Send a message */
static void send_to_sock(struct connection *con)
{
@@ -1537,7 +1563,7 @@ static void send_to_sock(struct connection *con)
if (con->sock == NULL)
goto out_connect;
- spin_lock(&con->writequeue_lock);
+ spin_lock_bh(&con->writequeue_lock);
for (;;) {
if (list_empty(&con->writequeue))
break;
@@ -1546,7 +1572,7 @@ static void send_to_sock(struct connection *con)
len = e->len;
offset = e->offset;
BUG_ON(len == 0 && e->users == 0);
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
ret = 0;
if (len) {
@@ -1574,10 +1600,10 @@ static void send_to_sock(struct connection *con)
count = 0;
}
- spin_lock(&con->writequeue_lock);
+ spin_lock_bh(&con->writequeue_lock);
writequeue_entry_complete(e, ret);
}
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
out:
mutex_unlock(&con->sock_mutex);
return;
@@ -1600,11 +1626,11 @@ static void clean_one_writequeue(struct connection *con)
{
struct writequeue_entry *e, *safe;
- spin_lock(&con->writequeue_lock);
+ spin_lock_bh(&con->writequeue_lock);
list_for_each_entry_safe(e, safe, &con->writequeue, list) {
free_entry(e);
}
- spin_unlock(&con->writequeue_lock);
+ spin_unlock_bh(&con->writequeue_lock);
}
/* Called from recovery when it knows that a node has
diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h
index fa735497dad8..345aed7e00cc 100644
--- a/fs/dlm/lowcomms.h
+++ b/fs/dlm/lowcomms.h
@@ -30,6 +30,7 @@ int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark);
int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len);
void dlm_lowcomms_put_buffer(void *mh);
void dlm_lowcomms_get_buffer(void *mh);
+void dlm_lowcomms_resend_buffer(void *mh);
#endif /* __LOWCOMMS_DOT_H__ */
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 5/8] fs: dlm: move out some hash functionality
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
` (3 preceding siblings ...)
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 4/8] fs: dlm: add functionality to re-transmit a message Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 6/8] fs: dlm: add union in dlm header for lockspace id Alexander Aring
` (2 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch moves out some lowcomms hash functionality into lowcomms
header to provide them to other layers like midcomms as well.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/lowcomms.c | 9 ---------
fs/dlm/lowcomms.h | 10 ++++++++++
2 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index d2be58496fd0..5cb6d7c9ddc1 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -59,7 +59,6 @@
#include "config.h"
#define NEEDED_RMEM (4*1024*1024)
-#define CONN_HASH_SIZE 32
/* Number of messages to send before rescheduling */
#define MAX_SEND_MSG_COUNT 25
@@ -166,14 +165,6 @@ static void sctp_connect_to_sock(struct connection *con);
static void tcp_connect_to_sock(struct connection *con);
static void dlm_tcp_shutdown(struct connection *con);
-/* This is deliberately very simple because most clusters have simple
- sequential nodeids, so we should be able to go straight to a connection
- struct in the array */
-static inline int nodeid_hash(int nodeid)
-{
- return nodeid & (CONN_HASH_SIZE-1);
-}
-
static struct connection *__find_con(int nodeid)
{
int r, idx;
diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h
index 345aed7e00cc..cacfc5620f54 100644
--- a/fs/dlm/lowcomms.h
+++ b/fs/dlm/lowcomms.h
@@ -13,6 +13,16 @@
#define __LOWCOMMS_DOT_H__
#define LOWCOMMS_MAX_TX_BUFFER_LEN 4096
+#define CONN_HASH_SIZE 32
+
+/* This is deliberately very simple because most clusters have simple
+ * sequential nodeids, so we should be able to go straight to a connection
+ * struct in the array
+ */
+static inline int nodeid_hash(int nodeid)
+{
+ return nodeid & (CONN_HASH_SIZE-1);
+}
/* switch to check if dlm is running */
extern int dlm_allow_conn;
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 6/8] fs: dlm: add union in dlm header for lockspace id
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
` (4 preceding siblings ...)
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 5/8] fs: dlm: move out some hash functionality Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 7/8] fs: dlm: add reliable connection if reconnect Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 8/8] fs: dlm: don't allow half transmitted messages Alexander Aring
7 siblings, 0 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch adds union inside the lockspace id to handle it also for
another use case for a different dlm command.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/dlm_internal.h | 5 ++++-
fs/dlm/lock.c | 8 ++++----
fs/dlm/midcomms.c | 1 -
fs/dlm/rcom.c | 4 ++--
fs/dlm/util.c | 6 ++++--
5 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 04fe9f525ac7..917de7367a32 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -377,7 +377,10 @@ static inline int rsb_flag(struct dlm_rsb *r, enum rsb_flags flag)
struct dlm_header {
uint32_t h_version;
- uint32_t h_lockspace;
+ union {
+ /* for DLM_MSG and DLM_RCOM */
+ uint32_t h_lockspace;
+ } u;
uint32_t h_nodeid; /* nodeid of sender */
uint16_t h_length;
uint8_t h_cmd; /* DLM_MSG, DLM_RCOM */
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index b3fd823009f4..daa5747c8556 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -3544,7 +3544,7 @@ static int _create_message(struct dlm_ls *ls, int mb_len,
ms = (struct dlm_message *) mb;
ms->m_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
- ms->m_header.h_lockspace = ls->ls_global_id;
+ ms->m_header.u.h_lockspace = ls->ls_global_id;
ms->m_header.h_nodeid = dlm_our_nodeid();
ms->m_header.h_length = mb_len;
ms->m_header.h_cmd = DLM_MSG;
@@ -5038,16 +5038,16 @@ void dlm_receive_buffer(union dlm_packet *p, int nodeid)
if (hd->h_nodeid != nodeid) {
log_print("invalid h_nodeid %d from %d lockspace %x",
- hd->h_nodeid, nodeid, hd->h_lockspace);
+ hd->h_nodeid, nodeid, hd->u.h_lockspace);
return;
}
- ls = dlm_find_lockspace_global(hd->h_lockspace);
+ ls = dlm_find_lockspace_global(hd->u.h_lockspace);
if (!ls) {
if (dlm_config.ci_log_debug) {
printk_ratelimited(KERN_DEBUG "dlm: invalid lockspace "
"%u from %d cmd %d type %d\n",
- hd->h_lockspace, nodeid, hd->h_cmd, type);
+ hd->u.h_lockspace, nodeid, hd->h_cmd, type);
}
if (hd->h_cmd == DLM_RCOM && type == DLM_RCOM_STATUS)
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index 2ea0449a82ab..d86dcc95f736 100644
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -149,4 +149,3 @@ int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
return ret;
}
-
diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index 7a7d4a8e4706..06f7a5f1d99d 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -49,7 +49,7 @@ static int create_rcom(struct dlm_ls *ls, int to_nodeid, int type, int len,
rc = (struct dlm_rcom *) mb;
rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
- rc->rc_header.h_lockspace = ls->ls_global_id;
+ rc->rc_header.u.h_lockspace = ls->ls_global_id;
rc->rc_header.h_nodeid = dlm_our_nodeid();
rc->rc_header.h_length = mb_len;
rc->rc_header.h_cmd = DLM_RCOM;
@@ -476,7 +476,7 @@ int dlm_send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
rc = (struct dlm_rcom *) mb;
rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
- rc->rc_header.h_lockspace = rc_in->rc_header.h_lockspace;
+ rc->rc_header.u.h_lockspace = rc_in->rc_header.u.h_lockspace;
rc->rc_header.h_nodeid = dlm_our_nodeid();
rc->rc_header.h_length = mb_len;
rc->rc_header.h_cmd = DLM_RCOM;
diff --git a/fs/dlm/util.c b/fs/dlm/util.c
index 74a8c5bfe9b5..58acbcc2081a 100644
--- a/fs/dlm/util.c
+++ b/fs/dlm/util.c
@@ -23,7 +23,8 @@
void header_out(struct dlm_header *hd)
{
hd->h_version = cpu_to_le32(hd->h_version);
- hd->h_lockspace = cpu_to_le32(hd->h_lockspace);
+ /* does it for others u32 in union as well */
+ hd->u.h_lockspace = cpu_to_le32(hd->u.h_lockspace);
hd->h_nodeid = cpu_to_le32(hd->h_nodeid);
hd->h_length = cpu_to_le16(hd->h_length);
}
@@ -31,7 +32,8 @@ void header_out(struct dlm_header *hd)
void header_in(struct dlm_header *hd)
{
hd->h_version = le32_to_cpu(hd->h_version);
- hd->h_lockspace = le32_to_cpu(hd->h_lockspace);
+ /* does it for others u32 in union as well */
+ hd->u.h_lockspace = le32_to_cpu(hd->u.h_lockspace);
hd->h_nodeid = le32_to_cpu(hd->h_nodeid);
hd->h_length = le16_to_cpu(hd->h_length);
}
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 7/8] fs: dlm: add reliable connection if reconnect
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
` (5 preceding siblings ...)
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 6/8] fs: dlm: add union in dlm header for lockspace id Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
2021-03-05 14:31 ` Paolo Abeni
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 8/8] fs: dlm: don't allow half transmitted messages Alexander Aring
7 siblings, 1 reply; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch introduce to make a tcp lowcomms connection reliable even if
reconnects occurs. This is done by an application layer re-transmission
handling and sequence numbers in dlm protocols. There are three new dlm
commands:
DLM_OPTS:
This will encapsulate an existing dlm message (and rcom message if they
don't have an own application side re-transmission handling). As optional
handling additional tlv's (type length fields) can be appended. This can
be for example a sequence number field. However because in DLM_OPTS the
lockspace field is unused and a sequence number is a mandatory field it
isn't made as a tlv and we put the sequence number inside the lockspace
id. The possibility to add optional options are still there for future
purposes.
DLM_ACK:
Just a dlm header to acknowledge the receive of a DLM_OPTS message to
it's sender.
DLM_FIN:
A new DLM message to synchronize pending message to the other dlm end if
the node want to disconnects. Each side waits until it receives this
message and disconnects. It's important that this message has nothing to
do with the application logic because it might run in a timeout if
acknowledge messages are dropped. The problem which we try to solve with
DLM_FIN is that the node membership is handled by corosync and not the
kernel dlm protocol itself, DLM_FIN tries to synchronize the kernel dlm
protocol with corosync join/leave membership callbacks.
To explain the basic functionality take a look into the
dlm_midcomms_receive_buffer() function. This function will take care
that dlm messages are delivered according to their sequence numbers and
request re-transmission via sending acknowledge messages. However there
exists three cases:
1. sequence number is the one which is expected. That means everything
is working fine. Additional there is always a check if the next
message was already queued for future, this will occur when there was
some messages drops before.
2. A sequence number is in the future, in this case we queue it for might
future delivery, see case 1.
3. A sequence number is in the past, in this case we drop this message
because it was already delivered.
To send acknowledge we always send the sequence number which is
expected, if the other node sends multiple acknowledge for the same
sequence numbers it will trigger a re-transmission. In case no acknowledge
is send back, a timer with a timeout handling is running and will trigger
a re-tranmission as well. Sending multiple ack's with the same sequence or
messages with the same sequence should not have any effects that breaks
dlm. Only messages in the far future can break dlm, that's why important
that the closing connection is right synchronized with DLM_FIN which
also resets the sequence numbers.
As RCOM_STATUS and RCOM_NAMES messages are the first messages which are
exchanged and they have they own re-transmission handling, there exists
logic that these messages must be first. If these messages arrives we
store the dlm version field. This handling is on DLM 3.1 and after this
patch 3.2 the same. A backwards compatibility handling has been added
which seems to work on tests without tcpkill, however it's not recommended
to use DLM 3.1 and 3.2 at the same time, because DLM 3.2 tries to fix long
term bugs in the DLM protocol.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/dlm_internal.h | 30 +-
fs/dlm/lockspace.c | 7 +-
fs/dlm/lowcomms.h | 7 +-
fs/dlm/midcomms.c | 1276 +++++++++++++++++++++++++++++++++++++++--
fs/dlm/rcom.c | 4 +-
5 files changed, 1269 insertions(+), 55 deletions(-)
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 917de7367a32..da2297705713 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -368,18 +368,26 @@ static inline int rsb_flag(struct dlm_rsb *r, enum rsb_flags flag)
/* dlm_header is first element of all structs sent between nodes */
#define DLM_HEADER_MAJOR 0x00030000
-#define DLM_HEADER_MINOR 0x00000001
+#define DLM_HEADER_MINOR 0x00000002
+
+#define DLM_VERSION_3_1 0x00030001
+#define DLM_VERSION_3_2 0x00030002
#define DLM_HEADER_SLOTS 0x00000001
#define DLM_MSG 1
#define DLM_RCOM 2
+#define DLM_OPTS 3
+#define DLM_ACK 4
+#define DLM_FIN 5
struct dlm_header {
uint32_t h_version;
union {
/* for DLM_MSG and DLM_RCOM */
uint32_t h_lockspace;
+ /* for DLM_ACK and DLM_OPTS */
+ uint32_t h_seq;
} u;
uint32_t h_nodeid; /* nodeid of sender */
uint16_t h_length;
@@ -387,7 +395,6 @@ struct dlm_header {
uint8_t h_pad;
};
-
#define DLM_MSG_REQUEST 1
#define DLM_MSG_CONVERT 2
#define DLM_MSG_UNLOCK 3
@@ -455,10 +462,29 @@ struct dlm_rcom {
char rc_buf[];
};
+struct dlm_opt_header {
+ uint16_t t_type;
+ uint16_t t_length;
+ uint32_t o_pad;
+ /* need to be 8 byte aligned */
+ char t_value[];
+};
+
+/* encapsulation header */
+struct dlm_opts {
+ struct dlm_header o_header;
+ uint8_t o_nextcmd;
+ uint8_t o_pad;
+ uint16_t o_optlen;
+ uint32_t o_pad2;
+ char o_opts[];
+};
+
union dlm_packet {
struct dlm_header header; /* common to other two */
struct dlm_message message;
struct dlm_rcom rcom;
+ struct dlm_opts opts;
};
#define DLM_RSF_NEED_SLOTS 0x00000001
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index bf5c55ef9d0d..2b738be8d7e4 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -567,7 +567,12 @@ static int new_lockspace(const char *name, const char *cluster,
mutex_init(&ls->ls_requestqueue_mutex);
mutex_init(&ls->ls_clear_proc_locks);
- ls->ls_recover_buf = kmalloc(LOWCOMMS_MAX_TX_BUFFER_LEN, GFP_NOFS);
+ /* Due backwards compatibility with 3.1 we need to use maximum
+ * possible dlm message size to be sure the message will fit and
+ * not having out of bounds issues. However on sending side 3.2
+ * might send less.
+ */
+ ls->ls_recover_buf = kmalloc(DEFAULT_BUFFER_SIZE, GFP_NOFS);
if (!ls->ls_recover_buf)
goto out_lkbidr;
diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h
index cacfc5620f54..1554d8c078c9 100644
--- a/fs/dlm/lowcomms.h
+++ b/fs/dlm/lowcomms.h
@@ -12,7 +12,12 @@
#ifndef __LOWCOMMS_DOT_H__
#define __LOWCOMMS_DOT_H__
-#define LOWCOMMS_MAX_TX_BUFFER_LEN 4096
+#include "dlm_internal.h"
+
+#define DLM_MIDCOMMS_OPT_LEN sizeof(struct dlm_opts)
+#define LOWCOMMS_MAX_TX_BUFFER_LEN (DEFAULT_BUFFER_SIZE - \
+ DLM_MIDCOMMS_OPT_LEN)
+
#define CONN_HASH_SIZE 32
/* This is deliberately very simple because most clusters have simple
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index d86dcc95f736..5458239fcf4f 100644
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -3,7 +3,7 @@
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
-** Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+** Copyright (C) 2004-2021 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
@@ -12,68 +12,859 @@
/*
* midcomms.c
*
- * This is the appallingly named "mid-level" comms layer.
+ * This is the appallingly named "mid-level" comms layer. It takes care
+ * about deliver an on application layer "reliable" communication above
+ * the used lowcomms transport layer.
*
- * Its purpose is to take packets from the "real" comms layer,
- * split them up into packets and pass them to the interested
- * part of the locking mechanism.
+ * How it works:
*
- * It also takes messages from the locking layer, formats them
- * into packets and sends them to the comms layer.
+ * The basic implementation about the implemented re-transmission algorithm
+ * is based on:
+ *
+ * https://web.archive.org/web/20200813052233/https://www.isi.edu/nsnam/DIRECTED_RESEARCH/DR_WANIDA/DR/JavisInActionFastRetransmitFrame.html
+ *
+ * There are two cases when a re-transmission occurs, both are described in
+ * the link above:
+ *
+ * - Multiple acks if the same sequence number are received agan, known as
+ * "fast re-transmit".
+ * - Ack timeout, if we don't receive an ack in a time of "DLM_RTO". Note
+ * that the this timeout will only be checked in the re-transmission
+ * time which runs ever "DLM_RTO_TIMER".
+ *
+ * Each node has a send_queue and recv_queue. The send_queue contains a
+ * reference to each msg handle of lowcomms and keeps the message alive
+ * so far it has not been acked. This is necessary to keep the message
+ * for a possible re-transmission.
+ *
+ * The recv_queue is used to keep messages saved which are having a
+ * sequence number in the future of the expected sequence number. If
+ * the message with the expected sequence number arrives and we have
+ * the next sequence number inside this queue it will be delivered to
+ * the upper layer. This queue should have entries only if there was a
+ * drop.
+ *
+ * How version detection works:
+ *
+ * Due the fact that dlm has pre-configured node addresses on every side
+ * it is in it's nature that every side connects at starts to transmit
+ * dlm messages which ends in a race. However DLM_RCOM_NAMES, DLM_RCOM_STATUS
+ * and their replies are the first messages which are exchanges. Due backwards
+ * compatibility these messages are not covered by the midcomms re-transmission
+ * layer. These messages have their own re-transmission handling in the dlm
+ * application layer. The version field of every node will be set on these RCOM
+ * messages as soon as they arrived and the node isn't yet part of the nodes
+ * hash. There exists also logic to detect version mismatched if something weird
+ * going on or the first messages isn't an expected one.
+ *
+ * How ack handling basically works:
+ *
+ * We ack every message with the "expected sequence number". A connection
+ * starts with the sequence number of 0. Receiving an ack will ack all
+ * dlm messages below it's sequence number. It's possible that an ack
+ * message can ack multiple dlm messages as the other side will send an
+ * sequence number back of it's expected sequence number. If there are
+ * multiple ack's received with the same sequence number it means that
+ * there was a drop and the other side telling us which message was
+ * dropped. The parameter "DLM_RETRANS_ACK_COUNT" can be used to change
+ * the amount of how many ack we need to received to start a retransmit.
+ * It's 3 but 2 should be fine as well as it's ery unlikely that we have
+ * out of order issues as RFC 2001 says to use 3. I can only think about
+ * multiple re-connection in a row where with drops which we might get
+ * ordering issues.
+ *
+ * In cases where nobody transmits any messages anymore but there was
+ * a drop, the re-transmission timer will kick in to resend messages
+ * which have an ack timeout.
+ *
+ * Sequence number cases:
+ *
+ * When a message arrives and function "dlm_midcomms_receive_buffer()" is
+ * called, it will detect by it's sequence number if the message is:
+ *
+ * - as expected => everything is fine
+ * - in the future => there was a drop, queue msg in recv_queue queue
+ * - in the past => ignore that message, because already delivered
+ *
+ * However we will always send an ack message to the other node to signal
+ * which is the current expected sequence number. This either acks
+ * messages or re-transmit on the other side, see ack handling.
+ *
+ * Termination:
+ *
+ * As this layer was implemented there was a problem discovered during
+ * connection termination. At midcomms_stop() call which occurs at the
+ * last dlm lockspace release the other side was still sending dlm
+ * messages after the connection was terminated. Further investigations
+ * shows that the membership organization is done by corosync and not
+ * the kernel dlm protocol itself. To make sure the node membership
+ * of a lockspace is synchronized with the kernel a DLM_FIN message was
+ * introduced. It is part of a synchronization mechanism to wait for
+ * the specific corosync events on both endpoints so a termination
+ * of sockets can be initiated. The "DLM_QUEUE_TIMEOUT" defines some
+ * timeout handling to wait for some synchronization points at
+ * connection termination.
+ *
+ * Future improvements:
+ *
+ * There exists some known issues/improvements of the dlm handling. Some
+ * of them should be done in a next major dlm version bump which makes
+ * it incompatible with previous versions.
+ *
+ * Unaligned memory access:
+ *
+ * There exists cases when the dlm message buffer length is not aligned
+ * to 8 byte. However seems nobody detected any problem with it. This
+ * can be fixed in the next major version bump of dlm.
+ *
+ * Version detection:
+ *
+ * The version detection and how it's done is related to backwards
+ * compatibility. There exists better ways to make a better handling.
+ * However this should be changed in the next major version bump of dlm.
+ *
+ * Ack handling:
+ *
+ * Currently we send an ack message for every dlm message. However we
+ * can ack multiple dlm messages with one ack by just delaying the ack
+ * message. Will reduce some traffic but makes the drop detection slower.
+ *
+ * Termination:
+ *
+ * Maybe handle nodes membership of lockspaces in dlm protocol itself,
+ * but that requires still synchronization with corosync.
+ */
+
+/* Debug switch to enable a 5 seconds sleep waiting of a termination.
+ * This can be useful to test fencing while termination is running.
+ * This requires a setup with only gfs2 as dlm user, so that the
+ * last umount will terminate the connection.
+ *
+ * However it became useful to test, while the 5 seconds block in umount
+ * just press the reset button. In a lot of dropping the termination
+ * process can could take several seconds.
*/
+#define DLM_DEBUG_FENCE_TERMINATION 0
#include "dlm_internal.h"
#include "lowcomms.h"
#include "config.h"
#include "lock.h"
+#include "util.h"
#include "midcomms.h"
-void *dlm_midcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
+/* init value for sequence numbers for testing purpose only e.g. overflows */
+#define DLM_SEQ_INIT 0
+/* if we get duplicates amount of acks we will start retransmit */
+#define DLM_RETRANS_ACK_COUNT 3
+/* timer timeout to start retransmit if we don't get an ack back */
+#define DLM_RTO msecs_to_jiffies(15 * 1000)
+#define DLM_RTO_TIMER msecs_to_jiffies(30 * 1000)
+/* 5 minutes wait to sync ending of dlm */
+#define DLM_QUEUE_TIMEOUT msecs_to_jiffies(5 * 60 * 1000)
+#define DLM_VERSION_NOT_SET 0
+
+struct midcomms_node {
+ int nodeid;
+ uint32_t version;
+ uint32_t seq_send;
+ uint32_t seq_next;
+ uint32_t seq_last;
+ /* note: this list may not sorted according to their seq */
+ struct list_head send_queue;
+ struct list_head recv_queue;
+ spinlock_t send_queue_lock;
+ atomic_t send_queue_cnt;
+ atomic_t recv_queue_cnt;
+#define DLM_NODE_FLAG_FIN 1
+#define DLM_NODE_FLAG_CLOSE 2
+#define DLM_NODE_FLAG_STOP_TX 3
+ unsigned long flags;
+ wait_queue_head_t fin_wait;
+ /* counts how many lockspaces are using this node
+ * this refcount is necessary to determine if the
+ * node wants to disconnect.
+ */
+ int users;
+
+ struct hlist_node hlist;
+ struct rcu_head rcu;
+};
+
+struct dlm_send_msg {
+ const struct dlm_header *inner_hd;
+ struct midcomms_node *node;
+ struct dlm_opts *opts;
+ unsigned long timeout;
+ int ack_count;
+ uint32_t seq;
+ void *mh;
+
+ struct list_head list;
+ struct rcu_head rcu;
+};
+
+struct dlm_recv_msg {
+ union dlm_packet *p;
+ uint32_t seq;
+
+ struct list_head list;
+};
+
+static struct timer_list dlm_retransmit_timer;
+
+static struct hlist_head node_hash[CONN_HASH_SIZE];
+static DEFINE_SPINLOCK(nodes_lock);
+DEFINE_STATIC_SRCU(nodes_srcu);
+
+/* This mutex prevents that midcomms_close() is running while
+ * stop() or remove(). As I experienced invalid memory access
+ * behaviours when DLM_DEBUG_FENCE_TERMINATION is enabled and
+ * resetting machines. I will end in some double deletion in nodes
+ * datastructure.
+ */
+static DEFINE_MUTEX(close_lock);
+
+static struct midcomms_node *__find_node(int nodeid, int r)
{
- return dlm_lowcomms_new_buffer(nodeid, len, allocation, ppc, NULL,
- NULL);
+ struct midcomms_node *node;
+ int idx;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
+ if (node->nodeid == nodeid) {
+ srcu_read_unlock(&nodes_srcu, idx);
+ return node;
+ }
+ }
+ srcu_read_unlock(&nodes_srcu, idx);
+
+ return NULL;
}
-void dlm_midcomms_commit_buffer(void *mh)
+static struct midcomms_node *nodeid2node(int nodeid, gfp_t alloc)
{
- dlm_lowcomms_commit_buffer(mh);
- dlm_lowcomms_put_buffer(mh);
+ struct midcomms_node *node, *tmp;
+ int r = nodeid_hash(nodeid);
+
+ node = __find_node(nodeid, r);
+ if (node || !alloc)
+ return node;
+
+ node = kzalloc(sizeof(*node), alloc);
+ if (!node)
+ return NULL;
+
+ node->nodeid = nodeid;
+ node->seq_next = DLM_SEQ_INIT;
+ node->seq_send = DLM_SEQ_INIT;
+ node->seq_last = DLM_SEQ_INIT;
+ spin_lock_init(&node->send_queue_lock);
+ atomic_set(&node->send_queue_cnt, 0);
+ INIT_LIST_HEAD(&node->send_queue);
+ atomic_set(&node->recv_queue_cnt, 0);
+ INIT_LIST_HEAD(&node->recv_queue);
+ init_waitqueue_head(&node->fin_wait);
+
+ spin_lock(&nodes_lock);
+ /* check again if there was somebody else
+ * earlier here to add the node
+ */
+ tmp = __find_node(nodeid, r);
+ if (tmp) {
+ spin_unlock(&nodes_lock);
+ kfree(node);
+ return tmp;
+ }
+
+ hlist_add_head_rcu(&node->hlist, &node_hash[r]);
+ spin_unlock(&nodes_lock);
+
+ return node;
}
-void *dlm_midcomms_stateless_get_buffer(int nodeid, int len, gfp_t allocation,
- char **ppc)
+static int dlm_send_ack(int nodeid, uint32_t seq)
{
- return dlm_lowcomms_new_buffer(nodeid, len, allocation, ppc, NULL,
- NULL);
+ int mb_len = sizeof(struct dlm_header);
+ struct dlm_header *m_header;
+ char *ppc;
+ void *mh;
+
+ mh = dlm_midcomms_stateless_get_buffer(nodeid, mb_len, GFP_NOFS, &ppc);
+ if (!mh)
+ return -ENOMEM;
+
+ m_header = (struct dlm_header *)ppc;
+
+ m_header->h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+ m_header->h_nodeid = dlm_our_nodeid();
+ m_header->h_length = mb_len;
+ m_header->h_cmd = DLM_ACK;
+ m_header->u.h_seq = seq;
+
+ header_out(m_header);
+ dlm_midcomms_stateless_commit_buffer(mh);
+
+ return 0;
}
-void dlm_midcomms_stateless_commit_buffer(void *mh)
+static int dlm_send_fin(int nodeid)
{
- dlm_lowcomms_commit_buffer(mh);
- dlm_lowcomms_put_buffer(mh);
+ int mb_len = sizeof(struct dlm_header);
+ struct dlm_header *m_header;
+ char *ppc;
+ void *mh;
+
+ mh = dlm_midcomms_get_buffer(nodeid, mb_len, GFP_NOFS, &ppc);
+ if (!mh)
+ return -ENOMEM;
+
+ m_header = (struct dlm_header *)ppc;
+
+ m_header->h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+ m_header->h_nodeid = dlm_our_nodeid();
+ m_header->h_length = mb_len;
+ m_header->h_cmd = DLM_FIN;
+
+ header_out(m_header);
+ dlm_midcomms_commit_buffer(mh);
+
+ return 0;
}
-void midcomms_add_member(int nodeid)
+static void dlm_send_msg_release(struct rcu_head *rcu)
{
+ struct dlm_send_msg *msg = container_of(rcu, struct dlm_send_msg, rcu);
+
+ dlm_lowcomms_put_buffer(msg->mh);
+ kfree(msg);
}
-void midcomms_remove_member(int nodeid)
+/* send_queue_lock must be held */
+static void dlm_send_msg_del(struct midcomms_node *node,
+ struct dlm_send_msg *msg)
{
+ list_del_rcu(&msg->list);
+ if (atomic_dec_and_test(&node->send_queue_cnt))
+ wake_up(&node->fin_wait);
+
+ call_rcu(&msg->rcu, dlm_send_msg_release);
}
-int dlm_midcomms_close(int nodeid)
+static void dlm_send_queue_flush(struct midcomms_node *node)
{
- return dlm_lowcomms_close(nodeid);
+ struct dlm_send_msg *msg;
+
+ rcu_read_lock();
+ spin_lock(&node->send_queue_lock);
+ list_for_each_entry_rcu(msg, &node->send_queue, list) {
+ dlm_send_msg_del(node, msg);
+ }
+ spin_unlock(&node->send_queue_lock);
+ rcu_read_unlock();
}
-int dlm_midcomms_start(void)
+static void dlm_recv_queue_flush(struct midcomms_node *node)
{
- return dlm_lowcomms_start();
+ struct dlm_recv_msg *msg, *tmp;
+
+ list_for_each_entry_safe(msg, tmp, &node->recv_queue, list) {
+ list_del(&msg->list);
+ if (atomic_dec_and_test(&node->recv_queue_cnt))
+ wake_up(&node->fin_wait);
+
+ kfree(msg->p);
+ kfree(msg);
+ }
}
-void dlm_midcomms_shutdown(void)
+static void dlm_midcomms_seq_receive_buffer(struct midcomms_node *node,
+ union dlm_packet *p)
{
- dlm_lowcomms_shutdown();
+ dlm_receive_buffer(p, node->nodeid);
+ node->seq_next++;
+}
+
+static void dlm_overflow_upper_ack(struct midcomms_node *node)
+{
+ struct dlm_send_msg *msg;
+
+ /* stop all seq transmissions for this node to ack all upper */
+ spin_lock(&node->send_queue_lock);
+ list_for_each_entry_rcu(msg, &node->send_queue, list) {
+ if (msg->seq > node->seq_send) {
+ log_print("seq overflow handling, will ack message %u from node %d",
+ msg->seq, node->nodeid);
+ dlm_send_msg_del(node, msg);
+ }
+ }
+ spin_unlock(&node->send_queue_lock);
+}
+
+static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
+{
+ struct dlm_send_msg *msg;
+
+ rcu_read_lock();
+ if (seq < node->seq_last) {
+ log_print("dlm seq overflow detected from node %d",
+ node->nodeid);
+ dlm_overflow_upper_ack(node);
+ }
+
+ list_for_each_entry_rcu(msg, &node->send_queue, list) {
+ if (msg->seq < seq) {
+ spin_lock(&node->send_queue_lock);
+ dlm_send_msg_del(node, msg);
+ spin_unlock(&node->send_queue_lock);
+ } else if (msg->seq == seq) {
+ msg->ack_count++;
+ if (msg->ack_count >= DLM_RETRANS_ACK_COUNT) {
+ log_print("retransmit because multiple acks received. message seq %u, nodeid: %d",
+ seq, node->nodeid);
+ dlm_lowcomms_resend_buffer(msg->mh);
+ }
+ }
+ }
+ rcu_read_unlock();
+
+ /* for overflow detection */
+ node->seq_last = seq;
+}
+
+static struct dlm_recv_msg *dlm_recv_create_msg(const union dlm_packet *p,
+ uint32_t seq)
+{
+ int mb_len = le16_to_cpu(p->header.h_length);
+ struct dlm_recv_msg *msg;
+
+ msg = kzalloc(sizeof(*msg), GFP_NOFS);
+ if (!msg)
+ return NULL;
+
+ msg->p = kzalloc(mb_len, GFP_NOFS);
+ if (!msg)
+ return NULL;
+
+ memcpy(msg->p, p, mb_len);
+ msg->seq = seq;
+
+ return msg;
+}
+
+static struct dlm_recv_msg *dlm_recv_get_msg_by_seq(struct midcomms_node *node,
+ uint32_t seq)
+{
+ struct dlm_recv_msg *msg;
+
+ list_for_each_entry(msg, &node->recv_queue, list) {
+ if (msg->seq == seq)
+ return msg;
+ }
+
+ return NULL;
+}
+
+static int dlm_recv_queue_future_msg(struct midcomms_node *node,
+ const union dlm_packet *p,
+ uint32_t seq)
+{
+ struct dlm_recv_msg *msg;
+
+ /* check if we already got the message */
+ msg = dlm_recv_get_msg_by_seq(node, seq);
+ if (msg)
+ return 0;
+
+ log_print("received message for the future, will queue it. expected seq: %u, message seq: %u, nodeid: %d",
+ node->seq_next, seq, node->nodeid);
+
+ msg = dlm_recv_create_msg(p, seq);
+ if (!msg)
+ return -ENOMEM;
+
+ atomic_inc(&node->recv_queue_cnt);
+ list_add_tail(&msg->list, &node->recv_queue);
+
+ return 0;
+}
+
+static void dlm_recv_queue_lookup_and_deliver_next(struct midcomms_node *node)
+{
+ struct dlm_recv_msg *msg;
+
+ msg = dlm_recv_get_msg_by_seq(node, node->seq_next);
+ while (msg) {
+ list_del(&msg->list);
+
+ log_print("deliver message from the queue because it was received in the past. message seq: %u, nodeid: %d",
+ node->seq_next, node->nodeid);
+ dlm_midcomms_seq_receive_buffer(node, msg->p);
+
+ if (atomic_dec_and_test(&node->recv_queue_cnt))
+ wake_up(&node->fin_wait);
+
+ kfree(msg->p);
+ kfree(msg);
+
+ msg = dlm_recv_get_msg_by_seq(node, node->seq_next);
+ }
+}
+
+static void dlm_midcomms_receive_buffer(union dlm_packet *p,
+ struct midcomms_node *node,
+ uint32_t seq)
+{
+ if (seq == node->seq_next) {
+ /* case when we received the expected next message */
+ dlm_midcomms_seq_receive_buffer(node, p);
+
+ /* lookup if we have the next message in the queue beceause
+ * we might got some message for the future in the past as
+ * we dropped some message which arrived now.
+ */
+ dlm_recv_queue_lookup_and_deliver_next(node);
+ } else if (seq > node->seq_next) {
+ /* We got some message in the future, we will queue it so
+ * we can deliver the message when the next message arrived.
+ */
+ dlm_recv_queue_future_msg(node, p, seq);
+ } else {
+ log_print("ignore message because it was already delivered. message seq: %u, expected: %u, nodeid: %d",
+ seq, node->seq_next, node->nodeid);
+ }
+
+ dlm_send_ack(node->nodeid, node->seq_next);
+}
+
+static struct midcomms_node *
+dlm_midcomms_recv_node_lookup(int nodeid, const union dlm_packet *p,
+ uint16_t msglen, int (*cb)(struct midcomms_node *node))
+{
+ struct midcomms_node *node;
+ gfp_t allocation = 0;
+ int ret;
+
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ if (msglen < sizeof(struct dlm_rcom)) {
+ log_print("rcom msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return NULL;
+ }
+
+ switch (le32_to_cpu(p->rcom.rc_type)) {
+ case DLM_RCOM_NAMES:
+ fallthrough;
+ case DLM_RCOM_NAMES_REPLY:
+ fallthrough;
+ case DLM_RCOM_STATUS:
+ fallthrough;
+ case DLM_RCOM_STATUS_REPLY:
+ allocation = GFP_NOFS;
+ break;
+ default:
+ break;
+ }
+
+ break;
+ default:
+ break;
+ }
+
+ node = nodeid2node(nodeid, allocation);
+ if (!node) {
+ switch (p->header.h_cmd) {
+ case DLM_OPTS:
+ if (msglen < sizeof(struct dlm_opts)) {
+ log_print("opts msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return NULL;
+ }
+
+ /* we only alloc a new node@receiving for the above
+ * RCOM messages. It can be that the other side is
+ * already gone and we cannot ack FIN messages anymore,
+ * we ignore it until the other side runs into an
+ * timeout. FIN messages are application stateless and
+ * it's not imortant to be acked since it is the last
+ * message before disconnect.
+ *
+ * we don't print a warning in this case.
+ */
+ switch (p->opts.o_nextcmd) {
+ case DLM_FIN:
+ return NULL;
+ default:
+ break;
+ }
+
+ break;
+ default:
+ break;
+ }
+
+ log_print("received dlm message cmd %d from node %d in an invalid sequence",
+ p->opts.o_nextcmd, nodeid);
+ return NULL;
+ }
+
+ ret = cb(node);
+ if (ret < 0)
+ return NULL;
+
+ return node;
+}
+
+static int dlm_midcomms_version_check_3_2(struct midcomms_node *node)
+{
+ switch (node->version) {
+ case DLM_VERSION_NOT_SET:
+ node->version = DLM_VERSION_3_2;
+ log_print("version 0x%08x for node %d detected", DLM_VERSION_3_2,
+ node->nodeid);
+ break;
+ case DLM_VERSION_3_2:
+ break;
+ default:
+ log_print("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
+ DLM_VERSION_3_2, node->nodeid, node->version);
+ return -1;
+ }
+
+ return 0;
+}
+
+#if 0
+static int dlm_parse_opts(void *opts, uint16_t optlen)
+{
+ struct dlm_opt_header *hd;
+ void *ptr = opts;
+ uint16_t length;
+
+ while (optlen > 0) {
+ hd = ptr;
+ switch (le16_to_cpu(hd->t_type)) {
+ /* add options here */
+ default:
+ break;
+ }
+
+ length = le16_to_cpu(hd->t_length);
+ ptr += length;
+ optlen -= length;
+ }
+
+ return 0;
+}
+#endif
+
+static int dlm_opts_check_msglen(union dlm_packet *p, uint16_t msglen, int nodeid)
+{
+ int len = msglen;
+
+ /* we only trust outer header msglen because
+ * it's checked against receive buffer length.
+ */
+ if (len < sizeof(struct dlm_opts))
+ return -1;
+ len -= sizeof(struct dlm_opts);
+
+ if (len < le16_to_cpu(p->opts.o_optlen))
+ return -1;
+ len -= le16_to_cpu(p->opts.o_optlen);
+
+ switch (p->opts.o_nextcmd) {
+ case DLM_FIN:
+ if (len < sizeof(struct dlm_header)) {
+ log_print("fin too small: %d, will skip this message from node %d",
+ len, nodeid);
+ return -1;
+ }
+
+ break;
+ case DLM_MSG:
+ if (len < sizeof(struct dlm_message)) {
+ log_print("msg too small: %d, will skip this message from node %d",
+ msglen, nodeid);
+ return -1;
+ }
+
+ break;
+ case DLM_RCOM:
+ if (len < sizeof(struct dlm_rcom)) {
+ log_print("rcom msg too small: %d, will skip this message from node %d",
+ len, nodeid);
+ return -1;
+ }
+
+ break;
+ default:
+ log_print("unsupported o_nextcmd received: %u, will skip this message from node %d",
+ p->opts.o_nextcmd, nodeid);
+ return -1;
+ }
+
+ return 0;
+}
+
+static void dlm_midcomms_receive_buffer_3_2(union dlm_packet *p, int nodeid)
+{
+ uint16_t msglen = le16_to_cpu(p->header.h_length);
+ struct midcomms_node *node;
+ uint32_t seq;
+ int ret;
+
+ node = dlm_midcomms_recv_node_lookup(nodeid, p, msglen,
+ dlm_midcomms_version_check_3_2);
+ if (!node)
+ return;
+
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ /* these rcom message we use to determine version.
+ * they have their own retransmission handling and
+ * are the first messages of dlm.
+ *
+ * length already checked.
+ */
+ switch (le32_to_cpu(p->rcom.rc_type)) {
+ case DLM_RCOM_NAMES:
+ fallthrough;
+ case DLM_RCOM_NAMES_REPLY:
+ fallthrough;
+ case DLM_RCOM_STATUS:
+ fallthrough;
+ case DLM_RCOM_STATUS_REPLY:
+ break;
+ default:
+ log_print("unsupported rcom type received: %u, will skip this message from node %d",
+ le32_to_cpu(p->rcom.rc_type), nodeid);
+ return;
+ }
+
+ dlm_receive_buffer(p, nodeid);
+ return;
+ case DLM_OPTS:
+ seq = le32_to_cpu(p->header.u.h_seq);
+
+ ret = dlm_opts_check_msglen(p, msglen, nodeid);
+ if (ret < 0) {
+ log_print("opts msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return;
+ }
+#if 0
+ ret = dlm_parse_opts(p->opts.o_opts, p->opts.o_optlen);
+ if (ret < 0)
+ return;
+#endif
+
+ p = (union dlm_packet *)((unsigned char *)p->opts.o_opts +
+ le16_to_cpu(p->opts.o_optlen));
+
+ /* recheck inner msglen just if it's not garbage */
+ msglen = le16_to_cpu(p->header.h_length);
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ if (msglen < sizeof(struct dlm_rcom)) {
+ log_print("inner rcom msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return;
+ }
+
+ break;
+ case DLM_MSG:
+ if (msglen < sizeof(struct dlm_message)) {
+ log_print("inner msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return;
+ }
+
+ break;
+ case DLM_FIN:
+ if (msglen < sizeof(struct dlm_header)) {
+ log_print("inner fin too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return;
+ }
+
+ if (seq != node->seq_next) {
+ dlm_send_ack(nodeid, node->seq_next);
+ return;
+ }
+
+ dlm_send_ack(nodeid, seq + 1);
+ set_bit(DLM_NODE_FLAG_FIN, &node->flags);
+ wake_up(&node->fin_wait);
+ return;
+ default:
+ log_print("unsupported inner h_cmd received: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return;
+ }
+
+ dlm_midcomms_receive_buffer(p, node, seq);
+ return;
+ case DLM_ACK:
+ seq = le32_to_cpu(p->header.u.h_seq);
+ dlm_receive_ack(node, seq);
+ return;
+ default:
+ log_print("unsupported h_cmd received: %u, will skip this message from node %d",
+ p->header.h_cmd, nodeid);
+ return;
+ }
+}
+
+static int dlm_midcomms_version_check_3_1(struct midcomms_node *node)
+{
+ switch (node->version) {
+ case DLM_VERSION_NOT_SET:
+ node->version = DLM_VERSION_3_1;
+ log_print("version 0x%08x for node %d detected", DLM_VERSION_3_1,
+ node->nodeid);
+ break;
+ case DLM_VERSION_3_1:
+ break;
+ default:
+ log_print("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
+ DLM_VERSION_3_1, node->nodeid, node->version);
+ return -1;
+ }
+
+ return 0;
+}
+
+static void dlm_midcomms_receive_buffer_3_1(union dlm_packet *p, int nodeid)
+{
+ uint16_t msglen = le16_to_cpu(p->header.h_length);
+ struct midcomms_node *node;
+
+ node = dlm_midcomms_recv_node_lookup(nodeid, p, msglen,
+ dlm_midcomms_version_check_3_1);
+ if (!node)
+ return;
+
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ /* length already checked */
+ break;
+ case DLM_MSG:
+ if (msglen < sizeof(struct dlm_message)) {
+ log_print("msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return;
+ }
+
+ break;
+ default:
+ log_print("unsupported h_cmd received: %u, will skip this message from node %d",
+ p->header.h_cmd, nodeid);
+ return;
+ }
+
+ dlm_receive_buffer(p, nodeid);
}
/*
@@ -116,32 +907,19 @@ int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
if (msglen > len)
break;
- switch (hd->h_cmd) {
- case DLM_MSG:
- if (msglen < sizeof(struct dlm_message)) {
- log_print("dlm msg too small: %u, will skip this message",
- msglen);
- goto skip;
- }
-
+ switch (le32_to_cpu(hd->h_version)) {
+ case DLM_VERSION_3_1:
+ dlm_midcomms_receive_buffer_3_1((union dlm_packet *)ptr, nodeid);
break;
- case DLM_RCOM:
- if (msglen < sizeof(struct dlm_rcom)) {
- log_print("dlm rcom msg too small: %u, will skip this message",
- msglen);
- goto skip;
- }
-
+ case DLM_VERSION_3_2:
+ dlm_midcomms_receive_buffer_3_2((union dlm_packet *)ptr, nodeid);
break;
default:
- log_print("unsupported h_cmd received: %u, will skip this message",
- hd->h_cmd);
- goto skip;
+ log_print("received invalid version header: %u from node %d, will skip this message",
+ le32_to_cpu(hd->h_version), nodeid);
+ break;
}
- dlm_receive_buffer((union dlm_packet *)ptr, nodeid);
-
-skip:
ret += msglen;
len -= msglen;
ptr += msglen;
@@ -149,3 +927,403 @@ int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
return ret;
}
+
+void *dlm_midcomms_stateless_get_buffer(int nodeid, int len, gfp_t allocation,
+ char **ppc)
+{
+ return dlm_lowcomms_new_buffer(nodeid, len, allocation,
+ ppc, NULL, NULL);
+}
+
+void dlm_midcomms_stateless_commit_buffer(void *mh)
+{
+ dlm_lowcomms_commit_buffer(mh);
+ dlm_lowcomms_put_buffer(mh);
+}
+
+static void dlm_fill_opts_header(struct dlm_opts *opts, uint16_t inner_len,
+ uint32_t seq)
+{
+ opts->o_header.h_cmd = DLM_OPTS;
+ opts->o_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+ opts->o_header.h_nodeid = dlm_our_nodeid();
+ opts->o_header.h_length = DLM_MIDCOMMS_OPT_LEN + inner_len;
+ opts->o_header.u.h_seq = seq;
+ header_out(&opts->o_header);
+}
+
+static void midcomms_get_buffer_cb(void *buf, void *priv)
+{
+ struct dlm_send_msg *msg = priv;
+
+ msg->seq = msg->node->seq_send++;
+}
+
+static void *dlm_midcomms_get_buffer_3_2(struct dlm_send_msg *msg, int nodeid,
+ int len, gfp_t allocation, char **ppc)
+{
+ struct dlm_opts *opts;
+ void *mh;
+
+ mh = dlm_lowcomms_new_buffer(nodeid, len + DLM_MIDCOMMS_OPT_LEN,
+ allocation, ppc, midcomms_get_buffer_cb, msg);
+ if (!mh)
+ return NULL;
+
+ opts = (struct dlm_opts *)*ppc;
+ msg->opts = opts;
+
+ /* add possible options here */
+ dlm_fill_opts_header(opts, len, msg->seq);
+
+ *ppc += sizeof(*opts);
+ msg->inner_hd = (const struct dlm_header *)*ppc;
+ return mh;
+}
+
+void *dlm_midcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
+{
+ struct midcomms_node *node;
+ struct dlm_send_msg *msg;
+ void *mh;
+
+ node = nodeid2node(nodeid, 0);
+ if (!node) {
+ WARN_ON_ONCE(1);
+ return NULL;
+ }
+
+ msg = kzalloc(sizeof(*msg), GFP_NOFS);
+ if (!msg)
+ return NULL;
+
+ msg->node = node;
+
+ switch (node->version) {
+ case DLM_VERSION_3_1:
+ mh = dlm_midcomms_stateless_get_buffer(nodeid, len, allocation,
+ ppc);
+ if (!mh) {
+ kfree(msg);
+ return NULL;
+ }
+
+ break;
+ case DLM_VERSION_3_2:
+ if (test_bit(DLM_NODE_FLAG_STOP_TX, &node->flags)) {
+ WARN_ON(1);
+ kfree(msg);
+ return NULL;
+ }
+
+ mh = dlm_midcomms_get_buffer_3_2(msg, nodeid, len, allocation,
+ ppc);
+ if (!mh) {
+ kfree(msg);
+ return NULL;
+ }
+
+ break;
+ default:
+ kfree(msg);
+ WARN_ON(1);
+ return NULL;
+ }
+
+ msg->mh = mh;
+
+ return msg;
+}
+
+static void dlm_midcomms_commit_buffer_3_2(struct dlm_send_msg *msg,
+ struct midcomms_node *node)
+{
+ atomic_inc(&node->send_queue_cnt);
+
+ /* nexthdr chain for fast lookup */
+ msg->opts->o_nextcmd = msg->inner_hd->h_cmd;
+
+ /* required to set before list_add because timer */
+ msg->timeout = jiffies + DLM_RTO;
+
+ spin_lock(&node->send_queue_lock);
+ list_add_tail_rcu(&msg->list, &node->send_queue);
+ spin_unlock(&node->send_queue_lock);
+
+ dlm_lowcomms_commit_buffer(msg->mh);
+}
+
+static void dlm_midcomms_commit_buffer_3_1(void *mh)
+{
+ dlm_midcomms_stateless_commit_buffer(mh);
+}
+
+void dlm_midcomms_commit_buffer(void *mh)
+{
+ struct dlm_send_msg *msg = mh;
+
+ switch (msg->node->version) {
+ case DLM_VERSION_3_1:
+ dlm_midcomms_commit_buffer_3_1(msg->mh);
+ /* msg is not part of rcu list in this case */
+ kfree(msg);
+ break;
+ case DLM_VERSION_3_2:
+ dlm_midcomms_commit_buffer_3_2(msg, msg->node);
+ break;
+ default:
+ WARN_ON(1);
+ break;
+ }
+}
+
+void midcomms_add_member(int nodeid)
+{
+ struct midcomms_node *node;
+
+ if (nodeid == dlm_our_nodeid())
+ return;
+
+ node = nodeid2node(nodeid, GFP_NOFS);
+ if (!node)
+ return;
+
+ node->users++;
+}
+
+static void midcomms_drain_and_fin(struct midcomms_node *node, bool active)
+{
+ int ret;
+
+ /* old protocol, we don't wait for pending operations */
+ switch (node->version) {
+ case DLM_VERSION_3_2:
+ break;
+ default:
+ return;
+ }
+
+ if (DLM_DEBUG_FENCE_TERMINATION)
+ msleep(5000);
+
+ ret = wait_event_timeout(node->fin_wait,
+ (!atomic_read(&node->send_queue_cnt) &&
+ !atomic_read(&node->recv_queue_cnt)) ||
+ test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
+ DLM_QUEUE_TIMEOUT);
+ if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
+ goto timed_out;
+
+ if (active) {
+ dlm_send_fin(node->nodeid);
+ set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
+
+ /* wait for other side dlm + fin */
+ ret = wait_event_timeout(node->fin_wait,
+ (!atomic_read(&node->send_queue_cnt) &&
+ !atomic_read(&node->recv_queue_cnt) &&
+ test_bit(DLM_NODE_FLAG_FIN, &node->flags)) ||
+ test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
+ DLM_QUEUE_TIMEOUT);
+ if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
+ goto timed_out;
+ } else {
+ /* wait other side is finished by it's fin */
+ ret = wait_event_timeout(node->fin_wait,
+ test_bit(DLM_NODE_FLAG_FIN, &node->flags) ||
+ test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
+ DLM_QUEUE_TIMEOUT);
+ if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
+ goto timed_out;
+
+ dlm_send_fin(node->nodeid);
+ set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
+
+ /* wait fin ack is back */
+ ret = wait_event_timeout(node->fin_wait,
+ (!atomic_read(&node->send_queue_cnt) &&
+ !atomic_read(&node->recv_queue_cnt)) ||
+ test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
+ DLM_QUEUE_TIMEOUT);
+ if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
+ goto timed_out;
+ }
+
+ return;
+
+timed_out:
+ if (!ret)
+ log_print("timed out from node %d", node->nodeid);
+
+ dlm_send_queue_flush(node);
+ synchronize_rcu();
+
+ dlm_recv_queue_flush(node);
+}
+
+static void midcomms_node_release(struct rcu_head *rcu)
+{
+ struct midcomms_node *node = container_of(rcu, struct midcomms_node, rcu);
+
+ /* be sure we have no queues left for 3.2 */
+ switch (node->version) {
+ case DLM_VERSION_3_2:
+ dlm_send_queue_flush(node);
+ dlm_recv_queue_flush(node);
+ break;
+ default:
+ break;
+ }
+
+ kfree(node);
+}
+
+void midcomms_remove_member(int nodeid)
+{
+ struct midcomms_node *node;
+
+ if (nodeid == dlm_our_nodeid())
+ return;
+
+ mutex_lock(&close_lock);
+ node = nodeid2node(nodeid, 0);
+ if (!node) {
+ mutex_unlock(&close_lock);
+ return;
+ }
+
+ node->users--;
+
+ /* hitting users count to zero means the
+ * other side is running dlm_midcomms_stop()
+ * we meet us to have a clean disconnect.
+ */
+ if (!node->users) {
+ midcomms_drain_and_fin(node, false);
+
+ spin_lock(&nodes_lock);
+ hlist_del_rcu(&node->hlist);
+ spin_unlock(&nodes_lock);
+
+ call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
+ }
+ mutex_unlock(&close_lock);
+}
+
+static void dlm_retransmit_timer_expires(struct timer_list *timer)
+{
+ unsigned long now = jiffies;
+ struct midcomms_node *node;
+ struct dlm_send_msg *msg;
+ int idx, i;
+
+ rcu_read_lock();
+ idx = srcu_read_lock(&nodes_srcu);
+ for (i = 0; i < CONN_HASH_SIZE; i++) {
+ hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
+ list_for_each_entry_rcu(msg, &node->send_queue, list) {
+ if (time_before_eq(msg->timeout, now)) {
+ log_print("retransmit because ack timeout. message seq %u, nodeid %d",
+ msg->seq, node->nodeid);
+
+ dlm_lowcomms_resend_buffer(msg->mh);
+ }
+ }
+ }
+ }
+ srcu_read_unlock(&nodes_srcu, idx);
+ rcu_read_unlock();
+
+ mod_timer(timer, jiffies + DLM_RTO_TIMER);
+}
+
+int dlm_midcomms_start(void)
+{
+ int i, ret;
+
+ for (i = 0; i < CONN_HASH_SIZE; i++)
+ INIT_HLIST_HEAD(&node_hash[i]);
+
+ ret = dlm_lowcomms_start();
+ if (ret == 0) {
+ timer_setup(&dlm_retransmit_timer,
+ dlm_retransmit_timer_expires, TIMER_DEFERRABLE);
+ mod_timer(&dlm_retransmit_timer,
+ jiffies + DLM_RTO_TIMER);
+ }
+
+ return ret;
+}
+
+void dlm_midcomms_shutdown(void)
+{
+ struct midcomms_node *node;
+ int i, idx;
+
+ mutex_lock(&close_lock);
+ idx = srcu_read_lock(&nodes_srcu);
+ for (i = 0; i < CONN_HASH_SIZE; i++) {
+ hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
+ midcomms_drain_and_fin(node, true);
+ }
+ }
+
+ del_timer_sync(&dlm_retransmit_timer);
+ dlm_lowcomms_shutdown();
+
+ for (i = 0; i < CONN_HASH_SIZE; i++) {
+ hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
+ spin_lock(&nodes_lock);
+ hlist_del_rcu(&node->hlist);
+ spin_unlock(&nodes_lock);
+
+ call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
+ }
+ }
+ srcu_read_unlock(&nodes_srcu, idx);
+ mutex_unlock(&close_lock);
+}
+
+int dlm_midcomms_close(int nodeid)
+{
+ struct midcomms_node *node;
+ int ret, idx;
+
+ if (nodeid == dlm_our_nodeid())
+ return 0;
+
+ /* keep nodes_srcu read lock to prevent node is released, because
+ * close can occur any time and we can't hold the close_lock.
+ */
+ idx = srcu_read_lock(&nodes_srcu);
+ /* Abort pending close/remove operation */
+ node = nodeid2node(nodeid, 0);
+ if (node) {
+ set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
+ set_bit(DLM_NODE_FLAG_CLOSE, &node->flags);
+ wake_up(&node->fin_wait);
+ }
+ srcu_read_unlock(&nodes_srcu, idx);
+
+ mutex_lock(&close_lock);
+ node = nodeid2node(nodeid, 0);
+ if (!node) {
+ mutex_unlock(&close_lock);
+ return dlm_lowcomms_close(nodeid);
+ }
+
+ spin_lock(&nodes_lock);
+ hlist_del_rcu(&node->hlist);
+ spin_unlock(&nodes_lock);
+
+ /* wait until there are all readers left e.g. timer */
+ synchronize_srcu(&nodes_srcu);
+
+ ret = dlm_lowcomms_close(nodeid);
+
+ mutex_unlock(&close_lock);
+
+ call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
+
+ return ret;
+}
diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index 06f7a5f1d99d..d731d9e65c3b 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -168,7 +168,7 @@ int dlm_rcom_status(struct dlm_ls *ls, int nodeid, uint32_t status_flags)
set_rcom_status(ls, (struct rcom_status *)rc->rc_buf, status_flags);
allow_sync_reply(ls, &rc->rc_id);
- memset(ls->ls_recover_buf, 0, LOWCOMMS_MAX_TX_BUFFER_LEN);
+ memset(ls->ls_recover_buf, 0, DEFAULT_BUFFER_SIZE);
send_rcom(ls, mh, rc, true);
@@ -291,7 +291,7 @@ int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
memcpy(rc->rc_buf, last_name, last_len);
allow_sync_reply(ls, &rc->rc_id);
- memset(ls->ls_recover_buf, 0, LOWCOMMS_MAX_TX_BUFFER_LEN);
+ memset(ls->ls_recover_buf, 0, DEFAULT_BUFFER_SIZE);
send_rcom(ls, mh, rc, true);
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 8/8] fs: dlm: don't allow half transmitted messages
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
` (6 preceding siblings ...)
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 7/8] fs: dlm: add reliable connection if reconnect Alexander Aring
@ 2021-03-04 19:56 ` Alexander Aring
7 siblings, 0 replies; 11+ messages in thread
From: Alexander Aring @ 2021-03-04 19:56 UTC (permalink / raw)
To: cluster-devel.redhat.com
This patch will clean a dirty page buffer if a reconnect occurs. If a page
buffer was half transmitted we cannot start inside the middle of a dlm
message if a node connects again. I observed invalid length receptions
errors and was guessing that this behaviour occurs, after this patch I
never saw an invalid message length again. This patch might drops more
messages for dlm version 3.1 but 3.1 can't deal with half messages as
well, for 3.2 it might trigger more re-transmissions but will not leave dlm
in a broken state.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/lowcomms.c | 84 ++++++++++++++++++++++++++++++-----------------
1 file changed, 54 insertions(+), 30 deletions(-)
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 5cb6d7c9ddc1..d70a554c6b2b 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -112,6 +112,7 @@ struct writequeue_entry {
int len;
int end;
int users;
+ bool dirty;
struct connection *con;
struct list_head msgs;
struct kref ref;
@@ -671,6 +672,36 @@ static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
}
+static void dlm_page_release(struct kref *kref)
+{
+ struct writequeue_entry *e = container_of(kref, struct writequeue_entry,
+ ref);
+
+ __free_page(e->page);
+ kfree(e);
+}
+
+static void dlm_msg_release(struct kref *kref)
+{
+ struct dlm_msg *msg = container_of(kref, struct dlm_msg, ref);
+
+ kref_put(&msg->entry->ref, dlm_page_release);
+ kfree(msg);
+}
+
+static void free_entry(struct writequeue_entry *e)
+{
+ struct dlm_msg *msg, *tmp;
+
+ list_for_each_entry_safe(msg, tmp, &e->msgs, list) {
+ list_del(&msg->list);
+ kref_put(&msg->ref, dlm_msg_release);
+ }
+
+ list_del(&e->list);
+ kref_put(&e->ref, dlm_page_release);
+}
+
static void dlm_close_sock(struct socket **sock)
{
if (*sock) {
@@ -685,6 +716,7 @@ static void close_connection(struct connection *con, bool and_other,
bool tx, bool rx)
{
bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
+ struct writequeue_entry *e;
if (tx && !closing && cancel_work_sync(&con->swork)) {
log_print("canceled swork for node %d", con->nodeid);
@@ -703,6 +735,26 @@ static void close_connection(struct connection *con, bool and_other,
close_connection(con->othercon, false, true, true);
}
+ /* if we send a writequeue entry only a half way, we drop the
+ * whole entry because reconnection and that we not start of the
+ * middle of a msg which will confuse the other end.
+ *
+ * we can always drop messages because retransmits, but what we
+ * cannot allow is to transmit half messages which may be processed
+ * at the other side.
+ *
+ * our policy is to start on a clean state when disconnects, we don't
+ * know what's send/received on transport layer in this case.
+ */
+ spin_lock_bh(&con->writequeue_lock);
+ if (!list_empty(&con->writequeue)) {
+ e = list_first_entry(&con->writequeue, struct writequeue_entry,
+ list);
+ if (e->dirty)
+ free_entry(e);
+ }
+ spin_unlock_bh(&con->writequeue_lock);
+
con->rx_leftover = 0;
con->retries = 0;
clear_bit(CF_CONNECTED, &con->flags);
@@ -978,36 +1030,6 @@ static int accept_from_sock(struct listen_connection *con)
return result;
}
-static void dlm_page_release(struct kref *kref)
-{
- struct writequeue_entry *e = container_of(kref, struct writequeue_entry,
- ref);
-
- __free_page(e->page);
- kfree(e);
-}
-
-static void dlm_msg_release(struct kref *kref)
-{
- struct dlm_msg *msg = container_of(kref, struct dlm_msg, ref);
-
- kref_put(&msg->entry->ref, dlm_page_release);
- kfree(msg);
-}
-
-static void free_entry(struct writequeue_entry *e)
-{
- struct dlm_msg *msg, *tmp;
-
- list_for_each_entry_safe(msg, tmp, &e->msgs, list) {
- list_del(&msg->list);
- kref_put(&msg->ref, dlm_msg_release);
- }
-
- list_del(&e->list);
- kref_put(&e->ref, dlm_page_release);
-}
-
/*
* writequeue_entry_complete - try to delete and free write queue entry
* @e: write queue entry to try to delete
@@ -1019,6 +1041,8 @@ static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
{
e->offset += completed;
e->len -= completed;
+ /* signal that page was half way transmitted */
+ e->dirty = true;
if (e->len == 0 && e->users == 0)
free_entry(e);
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 7/8] fs: dlm: add reliable connection if reconnect
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 7/8] fs: dlm: add reliable connection if reconnect Alexander Aring
@ 2021-03-05 14:31 ` Paolo Abeni
2021-03-05 15:36 ` Alexander Ahring Oder Aring
0 siblings, 1 reply; 11+ messages in thread
From: Paolo Abeni @ 2021-03-05 14:31 UTC (permalink / raw)
To: cluster-devel.redhat.com
Hello,
First thing first, overall this series looks little related to the
networking scope, and a I feel like I lack some of the context, anyway
let me add some early comments. Please perdom me for the possibly naive
questions.
Do you have a git tree available with this series applied?
On Thu, 2021-03-04 at 14:56 -0500, Alexander Aring wrote:
> This patch introduce to make a tcp lowcomms connection reliable even if
> reconnects occurs. This is done by an application layer re-transmission
> handling and sequence numbers in dlm protocols. There are three new dlm
> commands:
>
> DLM_OPTS:
>
> This will encapsulate an existing dlm message (and rcom message if they
> don't have an own application side re-transmission handling). As optional
> handling additional tlv's (type length fields) can be appended. This can
> be for example a sequence number field. However because in DLM_OPTS the
> lockspace field is unused and a sequence number is a mandatory field it
> isn't made as a tlv and we put the sequence number inside the lockspace
> id. The possibility to add optional options are still there for future
> purposes.
>
> DLM_ACK:
>
> Just a dlm header to acknowledge the receive of a DLM_OPTS message to
> it's sender.
>
> DLM_FIN:
>
> A new DLM message to synchronize pending message to the other dlm end if
> the node want to disconnects. Each side waits until it receives this
> message and disconnects. It's important that this message has nothing to
> do with the application logic because it might run in a timeout if
> acknowledge messages are dropped. The problem which we try to solve with
> DLM_FIN is that the node membership is handled by corosync and not the
> kernel dlm protocol itself, DLM_FIN tries to synchronize the kernel dlm
> protocol with corosync join/leave membership callbacks.
Looks like this patch defines new messages on the wire, are there any
existing public RFC/specs for that? Or is something completely new with
this patchset?
[...]
> diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
> index bf5c55ef9d0d..2b738be8d7e4 100644
> --- a/fs/dlm/lockspace.c
> +++ b/fs/dlm/lockspace.c
> @@ -567,7 +567,12 @@ static int new_lockspace(const char *name, const char *cluster,
> mutex_init(&ls->ls_requestqueue_mutex);
> mutex_init(&ls->ls_clear_proc_locks);
>
> - ls->ls_recover_buf = kmalloc(LOWCOMMS_MAX_TX_BUFFER_LEN, GFP_NOFS);
> + /* Due backwards compatibility with 3.1 we need to use maximum
> + * possible dlm message size to be sure the message will fit and
> + * not having out of bounds issues. However on sending side 3.2
> + * might send less.
> + */
> + ls->ls_recover_buf = kmalloc(DEFAULT_BUFFER_SIZE, GFP_NOFS);
in current net-next DEFAULT_BUFFER_SIZE == LOWCOMMS_MAX_TX_BUFFER_LEN
== 4096, so I'm likely missing some bits here...
[...]
> + * Unaligned memory access:
> + *
> + * There exists cases when the dlm message buffer length is not aligned
> + * to 8 byte. However seems nobody detected any problem with it. This
> + * can be fixed in the next major version bump of dlm.
Do you mean dlm_header 'h_length'? that should not be a problem, since
the field size is 16 bits. Or is something else?
[...]
> -void *dlm_midcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
> +/* init value for sequence numbers for testing purpose only e.g. overflows */
> +#define DLM_SEQ_INIT 0
> +/* if we get duplicates amount of acks we will start retransmit */
> +#define DLM_RETRANS_ACK_COUNT 3
> +/* timer timeout to start retransmit if we don't get an ack back */
> +#define DLM_RTO msecs_to_jiffies(15 * 1000)
> +#define DLM_RTO_TIMER msecs_to_jiffies(30 * 1000)
This looks like a very high timeout. How long is the expected average
time to serve a single request?
> +/* 5 minutes wait to sync ending of dlm */
> +#define DLM_QUEUE_TIMEOUT msecs_to_jiffies(5 * 60 * 1000)
> +#define DLM_VERSION_NOT_SET 0
> +
> +struct midcomms_node {
> + int nodeid;
> + uint32_t version;
> + uint32_t seq_send;
> + uint32_t seq_next;
> + uint32_t seq_last;
> + /* note: this list may not sorted according to their seq */
> + struct list_head send_queue;
> + struct list_head recv_queue;
> + spinlock_t send_queue_lock;
> + atomic_t send_queue_cnt;
> + atomic_t recv_queue_cnt;
> +#define DLM_NODE_FLAG_FIN 1
> +#define DLM_NODE_FLAG_CLOSE 2
> +#define DLM_NODE_FLAG_STOP_TX 3
> + unsigned long flags;
> + wait_queue_head_t fin_wait;
> + /* counts how many lockspaces are using this node
> + * this refcount is necessary to determine if the
> + * node wants to disconnect.
> + */
> + int users;
> +
> + struct hlist_node hlist;
> + struct rcu_head rcu;
> +};
> +
> +struct dlm_send_msg {
> + const struct dlm_header *inner_hd;
> + struct midcomms_node *node;
> + struct dlm_opts *opts;
> + unsigned long timeout;
> + int ack_count;
> + uint32_t seq;
> + void *mh;
> +
> + struct list_head list;
> + struct rcu_head rcu;
> +};
> +
> +struct dlm_recv_msg {
> + union dlm_packet *p;
> + uint32_t seq;
> +
> + struct list_head list;
> +};
> +
> +static struct timer_list dlm_retransmit_timer;
> +
> +static struct hlist_head node_hash[CONN_HASH_SIZE];
> +static DEFINE_SPINLOCK(nodes_lock);
> +DEFINE_STATIC_SRCU(nodes_srcu);
> +
> +/* This mutex prevents that midcomms_close() is running while
> + * stop() or remove(). As I experienced invalid memory access
> + * behaviours when DLM_DEBUG_FENCE_TERMINATION is enabled and
> + * resetting machines. I will end in some double deletion in nodes
> + * datastructure.
> + */
> +static DEFINE_MUTEX(close_lock);
> +
> +static struct midcomms_node *__find_node(int nodeid, int r)
> {
> - return dlm_lowcomms_new_buffer(nodeid, len, allocation, ppc, NULL,
> - NULL);
> + struct midcomms_node *node;
> + int idx;
> +
> + idx = srcu_read_lock(&nodes_srcu);
> + hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
> + if (node->nodeid == nodeid) {
> + srcu_read_unlock(&nodes_srcu, idx);
> + return node;
> + }
> + }
> + srcu_read_unlock(&nodes_srcu, idx);
> +
> + return NULL;
> }
>
> -void dlm_midcomms_commit_buffer(void *mh)
> +static struct midcomms_node *nodeid2node(int nodeid, gfp_t alloc)
> {
> - dlm_lowcomms_commit_buffer(mh);
> - dlm_lowcomms_put_buffer(mh);
> + struct midcomms_node *node, *tmp;
> + int r = nodeid_hash(nodeid);
> +
> + node = __find_node(nodeid, r);
> + if (node || !alloc)
> + return node;
This apparently returns a reference to a 'midcomms_node *' with no
additional lock nor rcu held.
AFAICS concurrent midcomms_remove_member() could delete and free the
node at any moment after this point.
In pratice that should be difficult to reproduce, but I guess syzkaller
with time could hit that - assuming cuncurrent midcomms_remove_member()
are possible at all.
[...]
> +static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
> +{
> + struct dlm_send_msg *msg;
> +
> + rcu_read_lock();
> + if (seq < node->seq_last) {
> + log_print("dlm seq overflow detected from node %d",
> + node->nodeid);
> + dlm_overflow_upper_ack(node);
> + }
I think this can be simplified using the 'before()' and 'after()'
function/macro from include/net/tcp.h to compare seq and msg->seq,
without explicitly checking for overflow and without storing the
previous ack in 'seq_last'.
> +
> + list_for_each_entry_rcu(msg, &node->send_queue, list) {
> + if (msg->seq < seq) {
> + spin_lock(&node->send_queue_lock);
> + dlm_send_msg_del(node, msg);
> + spin_unlock(&node->send_queue_lock);
> + } else if (msg->seq == seq) {
> + msg->ack_count++;
> + if (msg->ack_count >= DLM_RETRANS_ACK_COUNT) {
> + log_print("retransmit because multiple acks received. message seq %u, nodeid: %d",
> + seq, node->nodeid);
> + dlm_lowcomms_resend_buffer(msg->mh);
> + }
> + }
> + }
> + rcu_read_unlock();
> +
> + /* for overflow detection */
> + node->seq_last = seq;
> +}
[...]
> +static int dlm_recv_queue_future_msg(struct midcomms_node *node,
> + const union dlm_packet *p,
> + uint32_t seq)
> +{
> + struct dlm_recv_msg *msg;
> +
> + /* check if we already got the message */
> + msg = dlm_recv_get_msg_by_seq(node, seq);
> + if (msg)
> + return 0;
> +
> + log_print("received message for the future, will queue it. expected seq: %u, message seq: %u, nodeid: %d",
> + node->seq_next, seq, node->nodeid);
> +
> + msg = dlm_recv_create_msg(p, seq);
> + if (!msg)
> + return -ENOMEM;
> +
> + atomic_inc(&node->recv_queue_cnt);
> + list_add_tail(&msg->list, &node->recv_queue);
It looks like the amount of 'future' msg is unbounded. An evil or
bugged peer may cause the allocation of unlimited amount of memory
sending messages with high/out-of-sequence seq number.
TCP uses quite a bit of complexity to deal with the above - limiting
the amount of allocated memory per connection and trimming out-of-
sequence data under memory pressure.
But looks like dlm_process_incoming_buffer() happens
after kernel_recvmsg(), so this receive memory is not accounted anymore
by TCP. I guess some similar constraint should be applied here (e.g.
enqueue at most X messages).
I think a similar issue potentially exists on the sender side
Side note: if the 'future' msg list become very long (still due to
buggy or evil peer) traversing it could become costly, but looks like
the traversing happens in process context, so that should be not very
critical.
[...]
> +int dlm_midcomms_start(void)
> +{
> + int i, ret;
> +
> + for (i = 0; i < CONN_HASH_SIZE; i++)
> + INIT_HLIST_HEAD(&node_hash[i]);
> +
> + ret = dlm_lowcomms_start();
> + if (ret == 0) {
> + timer_setup(&dlm_retransmit_timer,
> + dlm_retransmit_timer_expires, TIMER_DEFERRABLE);
> + mod_timer(&dlm_retransmit_timer,
> + jiffies + DLM_RTO_TIMER);
It looks like the timer is never updated, that is, it will fire even
all the outstanding msgs are acked.
Should not be a problem anyway.
Cheers,
Paolo
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Cluster-devel] [PATCH dlm/next 7/8] fs: dlm: add reliable connection if reconnect
2021-03-05 14:31 ` Paolo Abeni
@ 2021-03-05 15:36 ` Alexander Ahring Oder Aring
0 siblings, 0 replies; 11+ messages in thread
From: Alexander Ahring Oder Aring @ 2021-03-05 15:36 UTC (permalink / raw)
To: cluster-devel.redhat.com
Hi,
On Fri, Mar 5, 2021 at 9:31 AM Paolo Abeni <pabeni@redhat.com> wrote:
>
> Hello,
>
> First thing first, overall this series looks little related to the
> networking scope, and a I feel like I lack some of the context, anyway
> let me add some early comments. Please perdom me for the possibly naive
> questions.
>
> Do you have a git tree available with this series applied?
>
No, but maybe I can do it with the new gitlab workflow and upload it
there. It's based on dlm next branch on [0]. Please report if there
are any problems to apply these patches.
> On Thu, 2021-03-04 at 14:56 -0500, Alexander Aring wrote:
> > This patch introduce to make a tcp lowcomms connection reliable even if
> > reconnects occurs. This is done by an application layer re-transmission
> > handling and sequence numbers in dlm protocols. There are three new dlm
> > commands:
> >
> > DLM_OPTS:
> >
> > This will encapsulate an existing dlm message (and rcom message if they
> > don't have an own application side re-transmission handling). As optional
> > handling additional tlv's (type length fields) can be appended. This can
> > be for example a sequence number field. However because in DLM_OPTS the
> > lockspace field is unused and a sequence number is a mandatory field it
> > isn't made as a tlv and we put the sequence number inside the lockspace
> > id. The possibility to add optional options are still there for future
> > purposes.
> >
> > DLM_ACK:
> >
> > Just a dlm header to acknowledge the receive of a DLM_OPTS message to
> > it's sender.
> >
> > DLM_FIN:
> >
> > A new DLM message to synchronize pending message to the other dlm end if
> > the node want to disconnects. Each side waits until it receives this
> > message and disconnects. It's important that this message has nothing to
> > do with the application logic because it might run in a timeout if
> > acknowledge messages are dropped. The problem which we try to solve with
> > DLM_FIN is that the node membership is handled by corosync and not the
> > kernel dlm protocol itself, DLM_FIN tries to synchronize the kernel dlm
> > protocol with corosync join/leave membership callbacks.
>
> Looks like this patch defines new messages on the wire, are there any
> existing public RFC/specs for that? Or is something completely new with
> this patchset?
>
No, it's a protocol based on a closed protocol in OpenVMS. Note that
"Open" doesn't mean anything related to Open Source or Open standard.
I did these extensions because of an old issue [1] from my mind and on
my own.
> [...]
> > diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
> > index bf5c55ef9d0d..2b738be8d7e4 100644
> > --- a/fs/dlm/lockspace.c
> > +++ b/fs/dlm/lockspace.c
> > @@ -567,7 +567,12 @@ static int new_lockspace(const char *name, const char *cluster,
> > mutex_init(&ls->ls_requestqueue_mutex);
> > mutex_init(&ls->ls_clear_proc_locks);
> >
> > - ls->ls_recover_buf = kmalloc(LOWCOMMS_MAX_TX_BUFFER_LEN, GFP_NOFS);
> > + /* Due backwards compatibility with 3.1 we need to use maximum
> > + * possible dlm message size to be sure the message will fit and
> > + * not having out of bounds issues. However on sending side 3.2
> > + * might send less.
> > + */
> > + ls->ls_recover_buf = kmalloc(DEFAULT_BUFFER_SIZE, GFP_NOFS);
>
> in current net-next DEFAULT_BUFFER_SIZE == LOWCOMMS_MAX_TX_BUFFER_LEN
> == 4096, so I'm likely missing some bits here...
>
LOWCOMMS_MAX_TX_BUFFER_LEN is updated in this patch and defines a new
application level maximum buffer size because we encapsulate a header
below it.
I agree these names are somehow misnamed but it is as it is currently.
> [...]
>
> > + * Unaligned memory access:
> > + *
> > + * There exists cases when the dlm message buffer length is not aligned
> > + * to 8 byte. However seems nobody detected any problem with it. This
> > + * can be fixed in the next major version bump of dlm.
>
> Do you mean dlm_header 'h_length'? that should not be a problem, since
> the field size is 16 bits. Or is something else?
>
No, I mean every field is 8 byte aligned, which is fine. However there
exists ways (triggered by userspace) to send a dlm message out with a
tail message payload of size which is not 8 byte aligned.
This makes problems at:
1. sending side due an internal buffer allocation mechanism which uses
next available space in a page buffer and this ends in an unaligned
pointer for the next message.
2. receiving side that we get an unaligned pointer while parsing that
message and pointing to the next message.
> [...]
>
> > -void *dlm_midcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
> > +/* init value for sequence numbers for testing purpose only e.g. overflows */
> > +#define DLM_SEQ_INIT 0
> > +/* if we get duplicates amount of acks we will start retransmit */
> > +#define DLM_RETRANS_ACK_COUNT 3
> > +/* timer timeout to start retransmit if we don't get an ack back */
> > +#define DLM_RTO msecs_to_jiffies(15 * 1000)
> > +#define DLM_RTO_TIMER msecs_to_jiffies(30 * 1000)
>
> This looks like a very high timeout. How long is the expected average
> time to serve a single request?
>
The response time depends on their networking setup. I think we should
not take care about an "expected average time to server" here, the
more interesting part to choose the right timeout value here are the
default timeouts of the cluster world, which are making assumptions
about "expected average time to server" as well.
> > +/* 5 minutes wait to sync ending of dlm */
> > +#define DLM_QUEUE_TIMEOUT msecs_to_jiffies(5 * 60 * 1000)
> > +#define DLM_VERSION_NOT_SET 0
> > +
> > +struct midcomms_node {
> > + int nodeid;
> > + uint32_t version;
> > + uint32_t seq_send;
> > + uint32_t seq_next;
> > + uint32_t seq_last;
> > + /* note: this list may not sorted according to their seq */
> > + struct list_head send_queue;
> > + struct list_head recv_queue;
> > + spinlock_t send_queue_lock;
> > + atomic_t send_queue_cnt;
> > + atomic_t recv_queue_cnt;
> > +#define DLM_NODE_FLAG_FIN 1
> > +#define DLM_NODE_FLAG_CLOSE 2
> > +#define DLM_NODE_FLAG_STOP_TX 3
> > + unsigned long flags;
> > + wait_queue_head_t fin_wait;
> > + /* counts how many lockspaces are using this node
> > + * this refcount is necessary to determine if the
> > + * node wants to disconnect.
> > + */
> > + int users;
> > +
> > + struct hlist_node hlist;
> > + struct rcu_head rcu;
> > +};
> > +
> > +struct dlm_send_msg {
> > + const struct dlm_header *inner_hd;
> > + struct midcomms_node *node;
> > + struct dlm_opts *opts;
> > + unsigned long timeout;
> > + int ack_count;
> > + uint32_t seq;
> > + void *mh;
> > +
> > + struct list_head list;
> > + struct rcu_head rcu;
> > +};
> > +
> > +struct dlm_recv_msg {
> > + union dlm_packet *p;
> > + uint32_t seq;
> > +
> > + struct list_head list;
> > +};
> > +
> > +static struct timer_list dlm_retransmit_timer;
> > +
> > +static struct hlist_head node_hash[CONN_HASH_SIZE];
> > +static DEFINE_SPINLOCK(nodes_lock);
> > +DEFINE_STATIC_SRCU(nodes_srcu);
> > +
> > +/* This mutex prevents that midcomms_close() is running while
> > + * stop() or remove(). As I experienced invalid memory access
> > + * behaviours when DLM_DEBUG_FENCE_TERMINATION is enabled and
> > + * resetting machines. I will end in some double deletion in nodes
> > + * datastructure.
> > + */
> > +static DEFINE_MUTEX(close_lock);
> > +
> > +static struct midcomms_node *__find_node(int nodeid, int r)
> > {
> > - return dlm_lowcomms_new_buffer(nodeid, len, allocation, ppc, NULL,
> > - NULL);
> > + struct midcomms_node *node;
> > + int idx;
> > +
> > + idx = srcu_read_lock(&nodes_srcu);
> > + hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
> > + if (node->nodeid == nodeid) {
> > + srcu_read_unlock(&nodes_srcu, idx);
> > + return node;
> > + }
> > + }
> > + srcu_read_unlock(&nodes_srcu, idx);
> > +
> > + return NULL;
> > }
> >
> > -void dlm_midcomms_commit_buffer(void *mh)
> > +static struct midcomms_node *nodeid2node(int nodeid, gfp_t alloc)
> > {
> > - dlm_lowcomms_commit_buffer(mh);
> > - dlm_lowcomms_put_buffer(mh);
> > + struct midcomms_node *node, *tmp;
> > + int r = nodeid_hash(nodeid);
> > +
> > + node = __find_node(nodeid, r);
> > + if (node || !alloc)
> > + return node;
>
> This apparently returns a reference to a 'midcomms_node *' with no
> additional lock nor rcu held.
>
Yes, it will not hold any rcu. The whole mechanism works because the
hotpath for a specific node will not run concurrent while removing and
freeing the node.
> AFAICS concurrent midcomms_remove_member() could delete and free the
> node at any moment after this point.
>
> In pratice that should be difficult to reproduce, but I guess syzkaller
> with time could hit that - assuming cuncurrent midcomms_remove_member()
> are possible at all.
>
Assuming that happens, it is a bug in other places as well. The
hotpath for the specific node should not run anymore when midcomms is
attempting to delete the specific node. To ensure this I could maybe
add more WARN_ON and some flags?
> [...]
>
> > +static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
> > +{
> > + struct dlm_send_msg *msg;
> > +
> > + rcu_read_lock();
> > + if (seq < node->seq_last) {
> > + log_print("dlm seq overflow detected from node %d",
> > + node->nodeid);
> > + dlm_overflow_upper_ack(node);
> > + }
>
> I think this can be simplified using the 'before()' and 'after()'
> function/macro from include/net/tcp.h to compare seq and msg->seq,
> without explicitly checking for overflow and without storing the
> previous ack in 'seq_last'.
>
Okay, thanks I was looking for a simpler solution for that.
> > +
> > + list_for_each_entry_rcu(msg, &node->send_queue, list) {
> > + if (msg->seq < seq) {
> > + spin_lock(&node->send_queue_lock);
> > + dlm_send_msg_del(node, msg);
> > + spin_unlock(&node->send_queue_lock);
> > + } else if (msg->seq == seq) {
> > + msg->ack_count++;
> > + if (msg->ack_count >= DLM_RETRANS_ACK_COUNT) {
> > + log_print("retransmit because multiple acks received. message seq %u, nodeid: %d",
> > + seq, node->nodeid);
> > + dlm_lowcomms_resend_buffer(msg->mh);
> > + }
> > + }
> > + }
> > + rcu_read_unlock();
> > +
> > + /* for overflow detection */
> > + node->seq_last = seq;
> > +}
>
> [...]
>
> > +static int dlm_recv_queue_future_msg(struct midcomms_node *node,
> > + const union dlm_packet *p,
> > + uint32_t seq)
> > +{
> > + struct dlm_recv_msg *msg;
> > +
> > + /* check if we already got the message */
> > + msg = dlm_recv_get_msg_by_seq(node, seq);
> > + if (msg)
> > + return 0;
> > +
> > + log_print("received message for the future, will queue it. expected seq: %u, message seq: %u, nodeid: %d",
> > + node->seq_next, seq, node->nodeid);
> > +
> > + msg = dlm_recv_create_msg(p, seq);
> > + if (!msg)
> > + return -ENOMEM;
> > +
> > + atomic_inc(&node->recv_queue_cnt);
> > + list_add_tail(&msg->list, &node->recv_queue);
>
> It looks like the amount of 'future' msg is unbounded. An evil or
> bugged peer may cause the allocation of unlimited amount of memory
> sending messages with high/out-of-sequence seq number.
>
> TCP uses quite a bit of complexity to deal with the above - limiting
> the amount of allocated memory per connection and trimming out-of-
> sequence data under memory pressure.
>
> But looks like dlm_process_incoming_buffer() happens
> after kernel_recvmsg(), so this receive memory is not accounted anymore
> by TCP. I guess some similar constraint should be applied here (e.g.
> enqueue at most X messages).
>
> I think a similar issue potentially exists on the sender side
>
> Side note: if the 'future' msg list become very long (still due to
> buggy or evil peer) traversing it could become costly, but looks like
> the traversing happens in process context, so that should be not very
> critical.
>
Yes, this whole concept works on trusted nodes/networking only. A
bugged peer hopefully gets fenced by corosync because of other
reasons. For now it's a very simple mechanism and I didn't put a lot
of TCP engineering of the last decades into it.
If such a thing happens I might be able to send a signal to corosync
to fence the peer?
> [...]
>
> > +int dlm_midcomms_start(void)
> > +{
> > + int i, ret;
> > +
> > + for (i = 0; i < CONN_HASH_SIZE; i++)
> > + INIT_HLIST_HEAD(&node_hash[i]);
> > +
> > + ret = dlm_lowcomms_start();
> > + if (ret == 0) {
> > + timer_setup(&dlm_retransmit_timer,
> > + dlm_retransmit_timer_expires, TIMER_DEFERRABLE);
> > + mod_timer(&dlm_retransmit_timer,
> > + jiffies + DLM_RTO_TIMER);
>
> It looks like the timer is never updated, that is, it will fire even
> all the outstanding msgs are acked.
>
> Should not be a problem anyway.
>
Yes, I can change it to fire the timer only if drops are detected. I
will do that.
Thanks.
- Alex
[0] https://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm.git/log/?h=next
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1162846
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2021-03-05 15:36 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-04 19:56 [Cluster-devel] [PATCH dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 1/8] fs: dlm: public header in out utility Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 2/8] fs: dlm: add more midcomms hooks Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 3/8] fs: dlm: make buffer handling per msg Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 4/8] fs: dlm: add functionality to re-transmit a message Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 5/8] fs: dlm: move out some hash functionality Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 6/8] fs: dlm: add union in dlm header for lockspace id Alexander Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 7/8] fs: dlm: add reliable connection if reconnect Alexander Aring
2021-03-05 14:31 ` Paolo Abeni
2021-03-05 15:36 ` Alexander Ahring Oder Aring
2021-03-04 19:56 ` [Cluster-devel] [PATCH dlm/next 8/8] fs: dlm: don't allow half transmitted messages Alexander Aring
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