[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 000000000000..4c5c08a8860e
--- /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);
+}
+