fs/ocfs2/slot_map.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * slot_map.c
   5  *
   6  *
   7  *
   8  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  */
  25
  26 #include <linux/types.h>
  27 #include <linux/slab.h>
  28 #include <linux/highmem.h>
  29
  30 #define MLOG_MASK_PREFIX ML_SUPER
  31 #include <cluster/masklog.h>
  32
  33 #include "ocfs2.h"
  34
  35 #include "dlmglue.h"
  36 #include "extent_map.h"
  37 #include "heartbeat.h"
  38 #include "inode.h"
  39 #include "slot_map.h"
  40 #include "super.h"
  41 #include "sysfile.h"
  42
  43 #include "buffer_head_io.h"
  44
  45 static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
  46                                     s16 global);
  47 static void __ocfs2_fill_slot(struct ocfs2_slot_info *si,
  48                               s16 slot_num,
  49                               s16 node_num);
  50
  51 /* post the slot information on disk into our slot_info struct. */
  52 void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
  53 {
  54         int i;
  55         __le16 *disk_info;
  56
  57         /* we don't read the slot block here as ocfs2_super_lock
  58          * should've made sure we have the most recent copy. */
  59         spin_lock(&si->si_lock);
  60         disk_info = (__le16 *) si->si_bh->b_data;
  61
  62         for (i = 0; i < si->si_size; i++)
  63                 si->si_global_node_nums[i] = le16_to_cpu(disk_info[i]);
  64
  65         spin_unlock(&si->si_lock);
  66 }
  67
  68 /* post the our slot info stuff into it's destination bh and write it
  69  * out. */
  70 int ocfs2_update_disk_slots(struct ocfs2_super *osb,
  71                             struct ocfs2_slot_info *si)
  72 {
  73         int status, i;
  74         __le16 *disk_info = (__le16 *) si->si_bh->b_data;
  75
  76         spin_lock(&si->si_lock);
  77         for (i = 0; i < si->si_size; i++)
  78                 disk_info[i] = cpu_to_le16(si->si_global_node_nums[i]);
  79         spin_unlock(&si->si_lock);
  80
  81         status = ocfs2_write_block(osb, si->si_bh, si->si_inode);
  82         if (status < 0)
  83                 mlog_errno(status);
  84
  85         return status;
  86 }
  87
  88 /* try to find global node in the slot info. Returns
  89  * OCFS2_INVALID_SLOT if nothing is found. */
  90 static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
  91                                     s16 global)
  92 {
  93         int i;
  94         s16 ret = OCFS2_INVALID_SLOT;
  95
  96         for(i = 0; i < si->si_num_slots; i++) {
  97                 if (global == si->si_global_node_nums[i]) {
  98                         ret = (s16) i;
  99                         break;
 100                 }
 101         }
 102         return ret;
 103 }
 104
 105 static s16 __ocfs2_find_empty_slot(struct ocfs2_slot_info *si, s16 preferred)
 106 {
 107         int i;
 108         s16 ret = OCFS2_INVALID_SLOT;
 109
 110         if (preferred >= 0 && preferred < si->si_num_slots) {
 111                 if (OCFS2_INVALID_SLOT == si->si_global_node_nums[preferred]) {
 112                         ret = preferred;
 113                         goto out;
 114                 }
 115         }
 116
 117         for(i = 0; i < si->si_num_slots; i++) {
 118                 if (OCFS2_INVALID_SLOT == si->si_global_node_nums[i]) {
 119                         ret = (s16) i;
 120                         break;
 121                 }
 122         }
 123 out:
 124         return ret;
 125 }
 126
 127 s16 ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
 128                            s16 global)
 129 {
 130         s16 ret;
 131
 132         spin_lock(&si->si_lock);
 133         ret = __ocfs2_node_num_to_slot(si, global);
 134         spin_unlock(&si->si_lock);
 135         return ret;
 136 }
 137
 138 static void __ocfs2_fill_slot(struct ocfs2_slot_info *si,
 139                               s16 slot_num,
 140                               s16 node_num)
 141 {
 142         BUG_ON(slot_num == OCFS2_INVALID_SLOT);
 143         BUG_ON(slot_num >= si->si_num_slots);
 144         BUG_ON((node_num != O2NM_INVALID_NODE_NUM) &&
 145                (node_num >= O2NM_MAX_NODES));
 146
 147         si->si_global_node_nums[slot_num] = node_num;
 148 }
 149
 150 void ocfs2_clear_slot(struct ocfs2_slot_info *si,
 151                       s16 slot_num)
 152 {
 153         spin_lock(&si->si_lock);
 154         __ocfs2_fill_slot(si, slot_num, OCFS2_INVALID_SLOT);
 155         spin_unlock(&si->si_lock);
 156 }
 157
 158 int ocfs2_init_slot_info(struct ocfs2_super *osb)
 159 {
 160         int status, i;
 161         u64 blkno;
 162         struct inode *inode = NULL;
 163         struct buffer_head *bh = NULL;
 164         struct ocfs2_slot_info *si;
 165
 166         si = kzalloc(sizeof(struct ocfs2_slot_info), GFP_KERNEL);
 167         if (!si) {
 168                 status = -ENOMEM;
 169                 mlog_errno(status);
 170                 goto bail;
 171         }
 172
 173         spin_lock_init(&si->si_lock);
 174         si->si_num_slots = osb->max_slots;
 175         si->si_size = OCFS2_MAX_SLOTS;
 176
 177         for(i = 0; i < si->si_num_slots; i++)
 178                 si->si_global_node_nums[i] = OCFS2_INVALID_SLOT;
 179
 180         inode = ocfs2_get_system_file_inode(osb, SLOT_MAP_SYSTEM_INODE,
 181                                             OCFS2_INVALID_SLOT);
 182         if (!inode) {
 183                 status = -EINVAL;
 184                 mlog_errno(status);
 185                 goto bail;
 186         }
 187
 188         status = ocfs2_extent_map_get_blocks(inode, 0ULL, &blkno, NULL, NULL);
 189         if (status < 0) {
 190                 mlog_errno(status);
 191                 goto bail;
 192         }
 193
 194         status = ocfs2_read_block(osb, blkno, &bh, 0, inode);
 195         if (status < 0) {
 196                 mlog_errno(status);
 197                 goto bail;
 198         }
 199
 200         si->si_inode = inode;
 201         si->si_bh = bh;
 202         osb->slot_info = si;
 203 bail:
 204         if (status < 0 && si)
 205                 ocfs2_free_slot_info(si);
 206
 207         return status;
 208 }
 209
 210 void ocfs2_free_slot_info(struct ocfs2_slot_info *si)
 211 {
 212         if (si->si_inode)
 213                 iput(si->si_inode);
 214         if (si->si_bh)
 215                 brelse(si->si_bh);
 216         kfree(si);
 217 }
 218
 219 int ocfs2_find_slot(struct ocfs2_super *osb)
 220 {
 221         int status;
 222         s16 slot;
 223         struct ocfs2_slot_info *si;
 224
 225         mlog_entry_void();
 226
 227         si = osb->slot_info;
 228
 229         ocfs2_update_slot_info(si);
 230
 231         spin_lock(&si->si_lock);
 232         /* search for ourselves first and take the slot if it already
 233          * exists. Perhaps we need to mark this in a variable for our
 234          * own journal recovery? Possibly not, though we certainly
 235          * need to warn to the user */
 236         slot = __ocfs2_node_num_to_slot(si, osb->node_num);
 237         if (slot == OCFS2_INVALID_SLOT) {
 238                 /* if no slot yet, then just take 1st available
 239                  * one. */
 240                 slot = __ocfs2_find_empty_slot(si, osb->preferred_slot);
 241                 if (slot == OCFS2_INVALID_SLOT) {
 242                         spin_unlock(&si->si_lock);
 243                         mlog(ML_ERROR, "no free slots available!\n");
 244                         status = -EINVAL;
 245                         goto bail;
 246                 }
 247         } else
 248                 mlog(ML_NOTICE, "slot %d is already allocated to this node!\n",
 249                      slot);
 250
 251         __ocfs2_fill_slot(si, slot, osb->node_num);
 252         osb->slot_num = slot;
 253         spin_unlock(&si->si_lock);
 254
 255         mlog(0, "taking node slot %d\n", osb->slot_num);
 256
 257         status = ocfs2_update_disk_slots(osb, si);
 258         if (status < 0)
 259                 mlog_errno(status);
 260
 261 bail:
 262         mlog_exit(status);
 263         return status;
 264 }
 265
 266 void ocfs2_put_slot(struct ocfs2_super *osb)
 267 {
 268         int status;
 269         struct ocfs2_slot_info *si = osb->slot_info;
 270
 271         if (!si)
 272                 return;
 273
 274         ocfs2_update_slot_info(si);
 275
 276         spin_lock(&si->si_lock);
 277         __ocfs2_fill_slot(si, osb->slot_num, OCFS2_INVALID_SLOT);
 278         osb->slot_num = OCFS2_INVALID_SLOT;
 279         spin_unlock(&si->si_lock);
 280
 281         status = ocfs2_update_disk_slots(osb, si);
 282         if (status < 0) {
 283                 mlog_errno(status);
 284                 goto bail;
 285         }
 286
 287 bail:
 288         osb->slot_info = NULL;
 289         ocfs2_free_slot_info(si);
 290 }
 291