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![David Teigland](/assets/img/avatar_default.png)
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>
423 lines
9.6 KiB
C
423 lines
9.6 KiB
C
/******************************************************************************
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*******************************************************************************
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**
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** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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** Copyright (C) 2004-2005 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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*******************************************************************************
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******************************************************************************/
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#include "dlm_internal.h"
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#include "lockspace.h"
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#include "member.h"
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#include "lowcomms.h"
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#include "rcom.h"
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#include "config.h"
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#include "memory.h"
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#include "recover.h"
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#include "util.h"
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#include "lock.h"
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#include "dir.h"
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static void put_free_de(struct dlm_ls *ls, struct dlm_direntry *de)
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{
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spin_lock(&ls->ls_recover_list_lock);
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list_add(&de->list, &ls->ls_recover_list);
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spin_unlock(&ls->ls_recover_list_lock);
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}
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static struct dlm_direntry *get_free_de(struct dlm_ls *ls, int len)
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{
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int found = FALSE;
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struct dlm_direntry *de;
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spin_lock(&ls->ls_recover_list_lock);
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list_for_each_entry(de, &ls->ls_recover_list, list) {
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if (de->length == len) {
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list_del(&de->list);
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de->master_nodeid = 0;
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memset(de->name, 0, len);
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found = TRUE;
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break;
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}
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}
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spin_unlock(&ls->ls_recover_list_lock);
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if (!found)
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de = allocate_direntry(ls, len);
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return de;
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}
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void dlm_clear_free_entries(struct dlm_ls *ls)
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{
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struct dlm_direntry *de;
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spin_lock(&ls->ls_recover_list_lock);
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while (!list_empty(&ls->ls_recover_list)) {
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de = list_entry(ls->ls_recover_list.next, struct dlm_direntry,
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list);
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list_del(&de->list);
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free_direntry(de);
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}
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spin_unlock(&ls->ls_recover_list_lock);
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}
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/*
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* We use the upper 16 bits of the hash value to select the directory node.
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* Low bits are used for distribution of rsb's among hash buckets on each node.
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*
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* To give the exact range wanted (0 to num_nodes-1), we apply a modulus of
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* num_nodes to the hash value. This value in the desired range is used as an
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* offset into the sorted list of nodeid's to give the particular nodeid.
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*/
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int dlm_hash2nodeid(struct dlm_ls *ls, uint32_t hash)
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{
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struct list_head *tmp;
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struct dlm_member *memb = NULL;
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uint32_t node, n = 0;
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int nodeid;
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if (ls->ls_num_nodes == 1) {
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nodeid = dlm_our_nodeid();
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goto out;
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}
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if (ls->ls_node_array) {
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node = (hash >> 16) % ls->ls_total_weight;
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nodeid = ls->ls_node_array[node];
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goto out;
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}
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/* make_member_array() failed to kmalloc ls_node_array... */
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node = (hash >> 16) % ls->ls_num_nodes;
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list_for_each(tmp, &ls->ls_nodes) {
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if (n++ != node)
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continue;
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memb = list_entry(tmp, struct dlm_member, list);
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break;
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}
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DLM_ASSERT(memb , printk("num_nodes=%u n=%u node=%u\n",
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ls->ls_num_nodes, n, node););
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nodeid = memb->nodeid;
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out:
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return nodeid;
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}
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int dlm_dir_nodeid(struct dlm_rsb *r)
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{
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return dlm_hash2nodeid(r->res_ls, r->res_hash);
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}
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static inline uint32_t dir_hash(struct dlm_ls *ls, char *name, int len)
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{
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uint32_t val;
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val = jhash(name, len, 0);
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val &= (ls->ls_dirtbl_size - 1);
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return val;
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}
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static void add_entry_to_hash(struct dlm_ls *ls, struct dlm_direntry *de)
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{
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uint32_t bucket;
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bucket = dir_hash(ls, de->name, de->length);
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list_add_tail(&de->list, &ls->ls_dirtbl[bucket].list);
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}
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static struct dlm_direntry *search_bucket(struct dlm_ls *ls, char *name,
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int namelen, uint32_t bucket)
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{
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struct dlm_direntry *de;
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list_for_each_entry(de, &ls->ls_dirtbl[bucket].list, list) {
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if (de->length == namelen && !memcmp(name, de->name, namelen))
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goto out;
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}
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de = NULL;
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out:
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return de;
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}
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void dlm_dir_remove_entry(struct dlm_ls *ls, int nodeid, char *name, int namelen)
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{
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struct dlm_direntry *de;
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uint32_t bucket;
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bucket = dir_hash(ls, name, namelen);
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write_lock(&ls->ls_dirtbl[bucket].lock);
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de = search_bucket(ls, name, namelen, bucket);
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if (!de) {
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log_error(ls, "remove fr %u none", nodeid);
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goto out;
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}
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if (de->master_nodeid != nodeid) {
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log_error(ls, "remove fr %u ID %u", nodeid, de->master_nodeid);
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goto out;
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}
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list_del(&de->list);
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free_direntry(de);
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out:
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write_unlock(&ls->ls_dirtbl[bucket].lock);
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}
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void dlm_dir_clear(struct dlm_ls *ls)
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{
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struct list_head *head;
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struct dlm_direntry *de;
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int i;
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DLM_ASSERT(list_empty(&ls->ls_recover_list), );
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for (i = 0; i < ls->ls_dirtbl_size; i++) {
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write_lock(&ls->ls_dirtbl[i].lock);
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head = &ls->ls_dirtbl[i].list;
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while (!list_empty(head)) {
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de = list_entry(head->next, struct dlm_direntry, list);
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list_del(&de->list);
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put_free_de(ls, de);
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}
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write_unlock(&ls->ls_dirtbl[i].lock);
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}
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}
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int dlm_recover_directory(struct dlm_ls *ls)
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{
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struct dlm_member *memb;
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struct dlm_direntry *de;
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char *b, *last_name = NULL;
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int error = -ENOMEM, last_len, count = 0;
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uint16_t namelen;
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log_debug(ls, "dlm_recover_directory");
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if (dlm_no_directory(ls))
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goto out_status;
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dlm_dir_clear(ls);
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last_name = kmalloc(DLM_RESNAME_MAXLEN, GFP_KERNEL);
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if (!last_name)
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goto out;
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list_for_each_entry(memb, &ls->ls_nodes, list) {
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memset(last_name, 0, DLM_RESNAME_MAXLEN);
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last_len = 0;
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for (;;) {
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error = dlm_recovery_stopped(ls);
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if (error)
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goto out_free;
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error = dlm_rcom_names(ls, memb->nodeid,
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last_name, last_len);
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if (error)
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goto out_free;
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schedule();
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/*
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* pick namelen/name pairs out of received buffer
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*/
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b = ls->ls_recover_buf + sizeof(struct dlm_rcom);
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for (;;) {
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memcpy(&namelen, b, sizeof(uint16_t));
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namelen = be16_to_cpu(namelen);
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b += sizeof(uint16_t);
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/* namelen of 0xFFFFF marks end of names for
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this node; namelen of 0 marks end of the
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buffer */
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if (namelen == 0xFFFF)
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goto done;
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if (!namelen)
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break;
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error = -ENOMEM;
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de = get_free_de(ls, namelen);
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if (!de)
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goto out_free;
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de->master_nodeid = memb->nodeid;
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de->length = namelen;
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last_len = namelen;
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memcpy(de->name, b, namelen);
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memcpy(last_name, b, namelen);
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b += namelen;
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add_entry_to_hash(ls, de);
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count++;
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}
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}
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done:
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;
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}
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out_status:
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error = 0;
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dlm_set_recover_status(ls, DLM_RS_DIR);
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log_debug(ls, "dlm_recover_directory %d entries", count);
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out_free:
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kfree(last_name);
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out:
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dlm_clear_free_entries(ls);
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return error;
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}
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static int get_entry(struct dlm_ls *ls, int nodeid, char *name,
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int namelen, int *r_nodeid)
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{
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struct dlm_direntry *de, *tmp;
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uint32_t bucket;
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bucket = dir_hash(ls, name, namelen);
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write_lock(&ls->ls_dirtbl[bucket].lock);
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de = search_bucket(ls, name, namelen, bucket);
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if (de) {
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*r_nodeid = de->master_nodeid;
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write_unlock(&ls->ls_dirtbl[bucket].lock);
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if (*r_nodeid == nodeid)
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return -EEXIST;
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return 0;
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}
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write_unlock(&ls->ls_dirtbl[bucket].lock);
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de = allocate_direntry(ls, namelen);
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if (!de)
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return -ENOMEM;
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de->master_nodeid = nodeid;
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de->length = namelen;
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memcpy(de->name, name, namelen);
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write_lock(&ls->ls_dirtbl[bucket].lock);
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tmp = search_bucket(ls, name, namelen, bucket);
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if (tmp) {
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free_direntry(de);
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de = tmp;
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} else {
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list_add_tail(&de->list, &ls->ls_dirtbl[bucket].list);
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}
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*r_nodeid = de->master_nodeid;
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write_unlock(&ls->ls_dirtbl[bucket].lock);
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return 0;
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}
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int dlm_dir_lookup(struct dlm_ls *ls, int nodeid, char *name, int namelen,
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int *r_nodeid)
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{
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return get_entry(ls, nodeid, name, namelen, r_nodeid);
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}
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/* Copy the names of master rsb's into the buffer provided.
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Only select names whose dir node is the given nodeid. */
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void dlm_copy_master_names(struct dlm_ls *ls, char *inbuf, int inlen,
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char *outbuf, int outlen, int nodeid)
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{
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struct list_head *list;
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struct dlm_rsb *start_r = NULL, *r = NULL;
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int offset = 0, start_namelen, error, dir_nodeid;
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char *start_name;
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uint16_t be_namelen;
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/*
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* Find the rsb where we left off (or start again)
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*/
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start_namelen = inlen;
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start_name = inbuf;
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if (start_namelen > 1) {
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/*
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* We could also use a find_rsb_root() function here that
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* searched the ls_root_list.
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*/
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error = dlm_find_rsb(ls, start_name, start_namelen, R_MASTER,
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&start_r);
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DLM_ASSERT(!error && start_r,
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printk("error %d\n", error););
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DLM_ASSERT(!list_empty(&start_r->res_root_list),
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dlm_print_rsb(start_r););
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dlm_put_rsb(start_r);
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}
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/*
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* Send rsb names for rsb's we're master of and whose directory node
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* matches the requesting node.
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*/
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down_read(&ls->ls_root_sem);
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if (start_r)
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list = start_r->res_root_list.next;
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else
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list = ls->ls_root_list.next;
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for (offset = 0; list != &ls->ls_root_list; list = list->next) {
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r = list_entry(list, struct dlm_rsb, res_root_list);
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if (r->res_nodeid)
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continue;
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dir_nodeid = dlm_dir_nodeid(r);
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if (dir_nodeid != nodeid)
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continue;
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/*
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* The block ends when we can't fit the following in the
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* remaining buffer space:
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* namelen (uint16_t) +
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* name (r->res_length) +
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* end-of-block record 0x0000 (uint16_t)
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*/
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if (offset + sizeof(uint16_t)*2 + r->res_length > outlen) {
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/* Write end-of-block record */
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be_namelen = 0;
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memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
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offset += sizeof(uint16_t);
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goto out;
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}
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be_namelen = cpu_to_be16(r->res_length);
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memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
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offset += sizeof(uint16_t);
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memcpy(outbuf + offset, r->res_name, r->res_length);
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offset += r->res_length;
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}
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/*
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* If we've reached the end of the list (and there's room) write a
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* terminating record.
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*/
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if ((list == &ls->ls_root_list) &&
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(offset + sizeof(uint16_t) <= outlen)) {
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be_namelen = 0xFFFF;
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memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
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offset += sizeof(uint16_t);
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}
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out:
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up_read(&ls->ls_root_sem);
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}
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