[DLM] The core of the DLM for GFS2/CLVM

This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.

It implements VAX-style locking modes.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>

1 files changed, 460 insertions, 0 deletions

diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
new file mode 100644
index 00000000000..4c5c08a8860
--- /dev/null
+++ b/fs/dlm/rcom.c
@@ -0,0 +1,460 @@
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "lowcomms.h"
+#include "midcomms.h"
+#include "rcom.h"
+#include "recover.h"
+#include "dir.h"
+#include "config.h"
+#include "memory.h"
+#include "lock.h"
+#include "util.h"
+
+
+static int rcom_response(struct dlm_ls *ls)
+{
+	return test_bit(LSFL_RCOM_READY, &ls->ls_flags);
+}
+
+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;
+	struct dlm_mhandle *mh;
+	char *mb;
+	int mb_len = sizeof(struct dlm_rcom) + len;
+
+	mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, GFP_KERNEL, &mb);
+	if (!mh) {
+		log_print("create_rcom to %d type %d len %d ENOBUFS",
+			  to_nodeid, type, len);
+		return -ENOBUFS;
+	}
+	memset(mb, 0, mb_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.h_nodeid = dlm_our_nodeid();
+	rc->rc_header.h_length = mb_len;
+	rc->rc_header.h_cmd = DLM_RCOM;
+
+	rc->rc_type = type;
+
+	*mh_ret = mh;
+	*rc_ret = rc;
+	return 0;
+}
+
+static void send_rcom(struct dlm_ls *ls, struct dlm_mhandle *mh,
+		      struct dlm_rcom *rc)
+{
+	dlm_rcom_out(rc);
+	dlm_lowcomms_commit_buffer(mh);
+}
+
+/* When replying to a status request, a node also sends back its
+   configuration values.  The requesting node then checks that the remote
+   node is configured the same way as itself. */
+
+static void make_config(struct dlm_ls *ls, struct rcom_config *rf)
+{
+	rf->rf_lvblen = ls->ls_lvblen;
+	rf->rf_lsflags = ls->ls_exflags;
+}
+
+static int check_config(struct dlm_ls *ls, struct rcom_config *rf, int nodeid)
+{
+	if (rf->rf_lvblen != ls->ls_lvblen ||
+	    rf->rf_lsflags != ls->ls_exflags) {
+		log_error(ls, "config mismatch: %d,%x nodeid %d: %d,%x",
+			  ls->ls_lvblen, ls->ls_exflags,
+			  nodeid, rf->rf_lvblen, rf->rf_lsflags);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+int dlm_rcom_status(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error = 0;
+
+	memset(ls->ls_recover_buf, 0, dlm_config.buffer_size);
+
+	if (nodeid == dlm_our_nodeid()) {
+		rc = (struct dlm_rcom *) ls->ls_recover_buf;
+		rc->rc_result = dlm_recover_status(ls);
+		goto out;
+	}
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_STATUS, 0, &rc, &mh);
+	if (error)
+		goto out;
+
+	send_rcom(ls, mh, rc);
+
+	error = dlm_wait_function(ls, &rcom_response);
+	clear_bit(LSFL_RCOM_READY, &ls->ls_flags);
+	if (error)
+		goto out;
+
+	rc = (struct dlm_rcom *) ls->ls_recover_buf;
+
+	if (rc->rc_result == -ESRCH) {
+		/* we pretend the remote lockspace exists with 0 status */
+		log_debug(ls, "remote node %d not ready", nodeid);
+		rc->rc_result = 0;
+	} else
+		error = check_config(ls, (struct rcom_config *) rc->rc_buf,
+				     nodeid);
+	/* the caller looks at rc_result for the remote recovery status */
+ out:
+	return error;
+}
+
+static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error, nodeid = rc_in->rc_header.h_nodeid;
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_STATUS_REPLY,
+			    sizeof(struct rcom_config), &rc, &mh);
+	if (error)
+		return;
+	rc->rc_result = dlm_recover_status(ls);
+	make_config(ls, (struct rcom_config *) rc->rc_buf);
+
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_status_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
+	set_bit(LSFL_RCOM_READY, &ls->ls_flags);
+	wake_up(&ls->ls_wait_general);
+}
+
+int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error = 0, len = sizeof(struct dlm_rcom);
+
+	memset(ls->ls_recover_buf, 0, dlm_config.buffer_size);
+
+	if (nodeid == dlm_our_nodeid()) {
+		dlm_copy_master_names(ls, last_name, last_len,
+		                      ls->ls_recover_buf + len,
+		                      dlm_config.buffer_size - len, nodeid);
+		goto out;
+	}
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_NAMES, last_len, &rc, &mh);
+	if (error)
+		goto out;
+	memcpy(rc->rc_buf, last_name, last_len);
+
+	send_rcom(ls, mh, rc);
+
+	error = dlm_wait_function(ls, &rcom_response);
+	clear_bit(LSFL_RCOM_READY, &ls->ls_flags);
+ out:
+	return error;
+}
+
+static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error, inlen, outlen;
+	int nodeid = rc_in->rc_header.h_nodeid;
+	uint32_t status = dlm_recover_status(ls);
+
+	/*
+	 * We can't run dlm_dir_rebuild_send (which uses ls_nodes) while
+	 * dlm_recoverd is running ls_nodes_reconfig (which changes ls_nodes).
+	 * It could only happen in rare cases where we get a late NAMES
+	 * message from a previous instance of recovery.
+	 */
+
+	if (!(status & DLM_RS_NODES)) {
+		log_debug(ls, "ignoring RCOM_NAMES from %u", nodeid);
+		return;
+	}
+
+	nodeid = rc_in->rc_header.h_nodeid;
+	inlen = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
+	outlen = dlm_config.buffer_size - sizeof(struct dlm_rcom);
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh);
+	if (error)
+		return;
+
+	dlm_copy_master_names(ls, rc_in->rc_buf, inlen, rc->rc_buf, outlen,
+			      nodeid);
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_names_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
+	set_bit(LSFL_RCOM_READY, &ls->ls_flags);
+	wake_up(&ls->ls_wait_general);
+}
+
+int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	struct dlm_ls *ls = r->res_ls;
+	int error;
+
+	error = create_rcom(ls, dir_nodeid, DLM_RCOM_LOOKUP, r->res_length,
+			    &rc, &mh);
+	if (error)
+		goto out;
+	memcpy(rc->rc_buf, r->res_name, r->res_length);
+	rc->rc_id = (unsigned long) r;
+
+	send_rcom(ls, mh, rc);
+ out:
+	return error;
+}
+
+static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	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);
+	if (error)
+		return;
+
+	error = dlm_dir_lookup(ls, nodeid, rc_in->rc_buf, len, &ret_nodeid);
+	if (error)
+		ret_nodeid = error;
+	rc->rc_result = ret_nodeid;
+	rc->rc_id = rc_in->rc_id;
+
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_lookup_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	dlm_recover_master_reply(ls, rc_in);
+}
+
+static void pack_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb,
+			   struct rcom_lock *rl)
+{
+	memset(rl, 0, sizeof(*rl));
+
+	rl->rl_ownpid = lkb->lkb_ownpid;
+	rl->rl_lkid = lkb->lkb_id;
+	rl->rl_exflags = lkb->lkb_exflags;
+	rl->rl_flags = lkb->lkb_flags;
+	rl->rl_lvbseq = lkb->lkb_lvbseq;
+	rl->rl_rqmode = lkb->lkb_rqmode;
+	rl->rl_grmode = lkb->lkb_grmode;
+	rl->rl_status = lkb->lkb_status;
+	rl->rl_wait_type = lkb->lkb_wait_type;
+
+	if (lkb->lkb_bastaddr)
+		rl->rl_asts |= AST_BAST;
+	if (lkb->lkb_astaddr)
+		rl->rl_asts |= AST_COMP;
+
+	if (lkb->lkb_range)
+		memcpy(rl->rl_range, lkb->lkb_range, 4*sizeof(uint64_t));
+
+	rl->rl_namelen = r->res_length;
+	memcpy(rl->rl_name, r->res_name, r->res_length);
+
+	/* FIXME: might we have an lvb without DLM_LKF_VALBLK set ?
+	   If so, receive_rcom_lock_args() won't take this copy. */
+
+	if (lkb->lkb_lvbptr)
+		memcpy(rl->rl_lvb, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
+}
+
+int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	struct dlm_ls *ls = r->res_ls;
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	struct rcom_lock *rl;
+	int error, len = sizeof(struct rcom_lock);
+
+	if (lkb->lkb_lvbptr)
+		len += ls->ls_lvblen;
+
+	error = create_rcom(ls, r->res_nodeid, DLM_RCOM_LOCK, len, &rc, &mh);
+	if (error)
+		goto out;
+
+	rl = (struct rcom_lock *) rc->rc_buf;
+	pack_rcom_lock(r, lkb, rl);
+	rc->rc_id = (unsigned long) r;
+
+	send_rcom(ls, mh, rc);
+ out:
+	return error;
+}
+
+static void receive_rcom_lock(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error, nodeid = rc_in->rc_header.h_nodeid;
+
+	dlm_recover_master_copy(ls, rc_in);
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_LOCK_REPLY,
+			    sizeof(struct rcom_lock), &rc, &mh);
+	if (error)
+		return;
+
+	/* We send back the same rcom_lock struct we received, but
+	   dlm_recover_master_copy() has filled in rl_remid and rl_result */
+
+	memcpy(rc->rc_buf, rc_in->rc_buf, sizeof(struct rcom_lock));
+	rc->rc_id = rc_in->rc_id;
+
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_lock_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	uint32_t status = dlm_recover_status(ls);
+
+	if (!(status & DLM_RS_DIR)) {
+		log_debug(ls, "ignoring RCOM_LOCK_REPLY from %u",
+			  rc_in->rc_header.h_nodeid);
+		return;
+	}
+
+	dlm_recover_process_copy(ls, rc_in);
+}
+
+static int send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	char *mb;
+	int mb_len = sizeof(struct dlm_rcom);
+
+	mh = dlm_lowcomms_get_buffer(nodeid, mb_len, GFP_KERNEL, &mb);
+	if (!mh)
+		return -ENOBUFS;
+	memset(mb, 0, mb_len);
+
+	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.h_nodeid = dlm_our_nodeid();
+	rc->rc_header.h_length = mb_len;
+	rc->rc_header.h_cmd = DLM_RCOM;
+
+	rc->rc_type = DLM_RCOM_STATUS_REPLY;
+	rc->rc_result = -ESRCH;
+
+	dlm_rcom_out(rc);
+	dlm_lowcomms_commit_buffer(mh);
+
+	return 0;
+}
+
+/* Called by dlm_recvd; corresponds to dlm_receive_message() but special
+   recovery-only comms are sent through here. */
+
+void dlm_receive_rcom(struct dlm_header *hd, int nodeid)
+{
+	struct dlm_rcom *rc = (struct dlm_rcom *) hd;
+	struct dlm_ls *ls;
+
+	dlm_rcom_in(rc);
+
+	/* If the lockspace doesn't exist then still send a status message
+	   back; it's possible that it just doesn't have its global_id yet. */
+
+	ls = dlm_find_lockspace_global(hd->h_lockspace);
+	if (!ls) {
+		log_print("lockspace %x from %d not found",
+			  hd->h_lockspace, nodeid);
+		send_ls_not_ready(nodeid, rc);
+		return;
+	}
+
+	if (dlm_recovery_stopped(ls) && (rc->rc_type != DLM_RCOM_STATUS)) {
+		log_error(ls, "ignoring recovery message %x from %d",
+			  rc->rc_type, nodeid);
+		goto out;
+	}
+
+	if (nodeid != rc->rc_header.h_nodeid) {
+		log_error(ls, "bad rcom nodeid %d from %d",
+			  rc->rc_header.h_nodeid, nodeid);
+		goto out;
+	}
+
+	switch (rc->rc_type) {
+	case DLM_RCOM_STATUS:
+		receive_rcom_status(ls, rc);
+		break;
+
+	case DLM_RCOM_NAMES:
+		receive_rcom_names(ls, rc);
+		break;
+
+	case DLM_RCOM_LOOKUP:
+		receive_rcom_lookup(ls, rc);
+		break;
+
+	case DLM_RCOM_LOCK:
+		receive_rcom_lock(ls, rc);
+		break;
+
+	case DLM_RCOM_STATUS_REPLY:
+		receive_rcom_status_reply(ls, rc);
+		break;
+
+	case DLM_RCOM_NAMES_REPLY:
+		receive_rcom_names_reply(ls, rc);
+		break;
+
+	case DLM_RCOM_LOOKUP_REPLY:
+		receive_rcom_lookup_reply(ls, rc);
+		break;
+
+	case DLM_RCOM_LOCK_REPLY:
+		receive_rcom_lock_reply(ls, rc);
+		break;
+
+	default:
+		DLM_ASSERT(0, printk("rc_type=%x\n", rc->rc_type););
+	}
+ out:
+	dlm_put_lockspace(ls);
+}
+