fs/ocfs2/sysfile.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * sysfile.c
   5  *
   6  * Initialize, read, write, etc. system files.
   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/fs.h>
  27 #include <linux/types.h>
  28 #include <linux/highmem.h>
  29
  30 #include <cluster/masklog.h>
  31
  32 #include "ocfs2.h"
  33
  34 #include "alloc.h"
  35 #include "dir.h"
  36 #include "inode.h"
  37 #include "journal.h"
  38 #include "sysfile.h"
  39
  40 #include "buffer_head_io.h"
  41
  42 static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  43                                                    int type,
  44                                                    u32 slot);
  45
  46 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  47 static struct lock_class_key ocfs2_sysfile_cluster_lock_key[NUM_SYSTEM_INODES];
  48 #endif
  49
  50 static inline int is_global_system_inode(int type)
  51 {
  52         return type >= OCFS2_FIRST_ONLINE_SYSTEM_INODE &&
  53                 type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE;
  54 }
  55
  56 static struct inode **get_local_system_inode(struct ocfs2_super *osb,
  57                                              int type,
  58                                              u32 slot)
  59 {
  60         int index;
  61         struct inode **local_system_inodes, **free = NULL;
  62
  63         BUG_ON(slot == OCFS2_INVALID_SLOT);
  64         BUG_ON(type < OCFS2_FIRST_LOCAL_SYSTEM_INODE ||
  65                type > OCFS2_LAST_LOCAL_SYSTEM_INODE);
  66
  67         spin_lock(&osb->osb_lock);
  68         local_system_inodes = osb->local_system_inodes;
  69         spin_unlock(&osb->osb_lock);
  70
  71         if (unlikely(!local_system_inodes)) {
  72                 local_system_inodes = kzalloc(sizeof(struct inode *) *
  73                                               NUM_LOCAL_SYSTEM_INODES *
  74                                               osb->max_slots,
  75                                               GFP_NOFS);
  76                 if (!local_system_inodes) {
  77                         mlog_errno(-ENOMEM);
  78                         /*
  79                          * return NULL here so that ocfs2_get_sytem_file_inodes
  80                          * will try to create an inode and use it. We will try
  81                          * to initialize local_system_inodes next time.
  82                          */
  83                         return NULL;
  84                 }
  85
  86                 spin_lock(&osb->osb_lock);
  87                 if (osb->local_system_inodes) {
  88                         /* Someone has initialized it for us. */
  89                         free = local_system_inodes;
  90                         local_system_inodes = osb->local_system_inodes;
  91                 } else
  92                         osb->local_system_inodes = local_system_inodes;
  93                 spin_unlock(&osb->osb_lock);
  94                 kfree(free);
  95         }
  96
  97         index = (slot * NUM_LOCAL_SYSTEM_INODES) +
  98                 (type - OCFS2_FIRST_LOCAL_SYSTEM_INODE);
  99
 100         return &local_system_inodes[index];
 101 }
 102
 103 struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb,
 104                                           int type,
 105                                           u32 slot)
 106 {
 107         struct inode *inode = NULL;
 108         struct inode **arr = NULL;
 109
 110         /* avoid the lookup if cached in local system file array */
 111         if (is_global_system_inode(type)) {
 112                 arr = &(osb->global_system_inodes[type]);
 113         } else
 114                 arr = get_local_system_inode(osb, type, slot);
 115
 116         mutex_lock(&osb->system_file_mutex);
 117         if (arr && ((inode = *arr) != NULL)) {
 118                 /* get a ref in addition to the array ref */
 119                 inode = igrab(inode);
 120                 mutex_unlock(&osb->system_file_mutex);
 121                 BUG_ON(!inode);
 122
 123                 return inode;
 124         }
 125
 126         /* this gets one ref thru iget */
 127         inode = _ocfs2_get_system_file_inode(osb, type, slot);
 128
 129         /* add one more if putting into array for first time */
 130         if (arr && inode) {
 131                 *arr = igrab(inode);
 132                 BUG_ON(!*arr);
 133         }
 134         mutex_unlock(&osb->system_file_mutex);
 135         return inode;
 136 }
 137
 138 static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
 139                                                    int type,
 140                                                    u32 slot)
 141 {
 142         char namebuf[40];
 143         struct inode *inode = NULL;
 144         u64 blkno;
 145         int status = 0;
 146
 147         ocfs2_sprintf_system_inode_name(namebuf,
 148                                         sizeof(namebuf),
 149                                         type, slot);
 150
 151         status = ocfs2_lookup_ino_from_name(osb->sys_root_inode, namebuf,
 152                                             strlen(namebuf), &blkno);
 153         if (status < 0) {
 154                 goto bail;
 155         }
 156
 157         inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE, type);
 158         if (IS_ERR(inode)) {
 159                 mlog_errno(PTR_ERR(inode));
 160                 inode = NULL;
 161                 goto bail;
 162         }
 163 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 164         if (type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
 165             type == LOCAL_GROUP_QUOTA_SYSTEM_INODE ||
 166             type == JOURNAL_SYSTEM_INODE) {
 167                 /* Ignore inode lock on these inodes as the lock does not
 168                  * really belong to any process and lockdep cannot handle
 169                  * that */
 170                 OCFS2_I(inode)->ip_inode_lockres.l_lockdep_map.key = NULL;
 171         } else {
 172                 lockdep_init_map(&OCFS2_I(inode)->ip_inode_lockres.
 173                                                                 l_lockdep_map,
 174                                  ocfs2_system_inodes[type].si_name,
 175                                  &ocfs2_sysfile_cluster_lock_key[type], 0);
 176         }
 177 #endif
 178 bail:
 179
 180         return inode;
 181 }
 182