573c24c4af
Replace all GFP_KERNEL and ls_allocation with GFP_NOFS. ls_allocation would be GFP_KERNEL for userland lockspaces and GFP_NOFS for file system lockspaces. It was discovered that any lockspaces on the system can affect all others by triggering memory reclaim in the file system which could in turn call back into the dlm to acquire locks, deadlocking dlm threads that were shared by all lockspaces, like dlm_recv. Signed-off-by: David Teigland <teigland@redhat.com>
152 lines
3 KiB
C
152 lines
3 KiB
C
/*
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* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License v.2.
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*/
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#include <net/genetlink.h>
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#include <linux/dlm.h>
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#include <linux/dlm_netlink.h>
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#include "dlm_internal.h"
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static uint32_t dlm_nl_seqnum;
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static uint32_t listener_nlpid;
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static struct genl_family family = {
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.id = GENL_ID_GENERATE,
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.name = DLM_GENL_NAME,
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.version = DLM_GENL_VERSION,
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};
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static int prepare_data(u8 cmd, struct sk_buff **skbp, size_t size)
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{
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struct sk_buff *skb;
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void *data;
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skb = genlmsg_new(size, GFP_NOFS);
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if (!skb)
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return -ENOMEM;
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/* add the message headers */
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data = genlmsg_put(skb, 0, dlm_nl_seqnum++, &family, 0, cmd);
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if (!data) {
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nlmsg_free(skb);
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return -EINVAL;
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}
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*skbp = skb;
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return 0;
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}
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static struct dlm_lock_data *mk_data(struct sk_buff *skb)
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{
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struct nlattr *ret;
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ret = nla_reserve(skb, DLM_TYPE_LOCK, sizeof(struct dlm_lock_data));
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if (!ret)
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return NULL;
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return nla_data(ret);
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}
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static int send_data(struct sk_buff *skb)
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{
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struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
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void *data = genlmsg_data(genlhdr);
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int rv;
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rv = genlmsg_end(skb, data);
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if (rv < 0) {
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nlmsg_free(skb);
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return rv;
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}
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return genlmsg_unicast(&init_net, skb, listener_nlpid);
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}
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static int user_cmd(struct sk_buff *skb, struct genl_info *info)
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{
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listener_nlpid = info->snd_pid;
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printk("user_cmd nlpid %u\n", listener_nlpid);
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return 0;
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}
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static struct genl_ops dlm_nl_ops = {
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.cmd = DLM_CMD_HELLO,
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.doit = user_cmd,
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};
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int __init dlm_netlink_init(void)
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{
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int rv;
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rv = genl_register_family(&family);
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if (rv)
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return rv;
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rv = genl_register_ops(&family, &dlm_nl_ops);
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if (rv < 0)
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goto err;
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return 0;
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err:
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genl_unregister_family(&family);
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return rv;
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}
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void dlm_netlink_exit(void)
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{
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genl_unregister_ops(&family, &dlm_nl_ops);
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genl_unregister_family(&family);
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}
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static void fill_data(struct dlm_lock_data *data, struct dlm_lkb *lkb)
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{
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struct dlm_rsb *r = lkb->lkb_resource;
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memset(data, 0, sizeof(struct dlm_lock_data));
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data->version = DLM_LOCK_DATA_VERSION;
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data->nodeid = lkb->lkb_nodeid;
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data->ownpid = lkb->lkb_ownpid;
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data->id = lkb->lkb_id;
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data->remid = lkb->lkb_remid;
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data->status = lkb->lkb_status;
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data->grmode = lkb->lkb_grmode;
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data->rqmode = lkb->lkb_rqmode;
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if (lkb->lkb_ua)
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data->xid = lkb->lkb_ua->xid;
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if (r) {
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data->lockspace_id = r->res_ls->ls_global_id;
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data->resource_namelen = r->res_length;
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memcpy(data->resource_name, r->res_name, r->res_length);
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}
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}
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void dlm_timeout_warn(struct dlm_lkb *lkb)
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{
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struct sk_buff *uninitialized_var(send_skb);
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struct dlm_lock_data *data;
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size_t size;
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int rv;
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size = nla_total_size(sizeof(struct dlm_lock_data)) +
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nla_total_size(0); /* why this? */
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rv = prepare_data(DLM_CMD_TIMEOUT, &send_skb, size);
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if (rv < 0)
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return;
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data = mk_data(send_skb);
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if (!data) {
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nlmsg_free(send_skb);
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return;
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}
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fill_data(data, lkb);
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send_data(send_skb);
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}
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