release/src-rt-6.x.4708/linux/linux-2.6.36/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 #define MLOG_MASK_PREFIX ML_INODE
  31 #include <cluster/masklog.h>
  32
  33 #include "ocfs2.h"
  34
  35 #include "alloc.h"
  36 #include "dir.h"
  37 #include "inode.h"
  38 #include "journal.h"
  39 #include "sysfile.h"
  40
  41 #include "buffer_head_io.h"
  42
  43 static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  44                                                    int type,
  45                                                    u32 slot);
  46
  47 static inline int is_global_system_inode(int type);
  48 static inline int is_in_system_inode_array(struct ocfs2_super *osb,
  49                                            int type,
  50                                            u32 slot);
  51
  52 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  53 static struct lock_class_key ocfs2_sysfile_cluster_lock_key[NUM_SYSTEM_INODES];
  54 #endif
  55
  56 static inline int is_global_system_inode(int type)
  57 {
  58         return type >= OCFS2_FIRST_ONLINE_SYSTEM_INODE &&
  59                 type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE;
  60 }
  61
  62 static inline int is_in_system_inode_array(struct ocfs2_super *osb,
  63                                            int type,
  64                                            u32 slot)
  65 {
  66         return slot == osb->slot_num || is_global_system_inode(type);
  67 }
  68
  69 struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  70                                           int type,
  71                                           u32 slot)
  72 {
  73         struct inode *inode = NULL;
  74         struct inode **arr = NULL;
  75
  76         /* avoid the lookup if cached in local system file array */
  77         if (is_in_system_inode_array(osb, type, slot))
  78                 arr = &(osb->system_inodes[type]);
  79
  80         if (arr && ((inode = *arr) != NULL)) {
  81                 /* get a ref in addition to the array ref */
  82                 inode = igrab(inode);
  83                 BUG_ON(!inode);
  84
  85                 return inode;
  86         }
  87
  88         /* this gets one ref thru iget */
  89         inode = _ocfs2_get_system_file_inode(osb, type, slot);
  90
  91         /* add one more if putting into array for first time */
  92         if (arr && inode) {
  93                 *arr = igrab(inode);
  94                 BUG_ON(!*arr);
  95         }
  96         return inode;
  97 }
  98
  99 static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
 100                                                    int type,
 101                                                    u32 slot)
 102 {
 103         char namebuf[40];
 104         struct inode *inode = NULL;
 105         u64 blkno;
 106         int status = 0;
 107
 108         ocfs2_sprintf_system_inode_name(namebuf,
 109                                         sizeof(namebuf),
 110                                         type, slot);
 111
 112         status = ocfs2_lookup_ino_from_name(osb->sys_root_inode, namebuf,
 113                                             strlen(namebuf), &blkno);
 114         if (status < 0) {
 115                 goto bail;
 116         }
 117
 118         inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE, type);
 119         if (IS_ERR(inode)) {
 120                 mlog_errno(PTR_ERR(inode));
 121                 inode = NULL;
 122                 goto bail;
 123         }
 124 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 125         if (type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
 126             type == LOCAL_GROUP_QUOTA_SYSTEM_INODE ||
 127             type == JOURNAL_SYSTEM_INODE) {
 128                 /* Ignore inode lock on these inodes as the lock does not
 129                  * really belong to any process and lockdep cannot handle
 130                  * that */
 131                 OCFS2_I(inode)->ip_inode_lockres.l_lockdep_map.key = NULL;
 132         } else {
 133                 lockdep_init_map(&OCFS2_I(inode)->ip_inode_lockres.
 134                                                                 l_lockdep_map,
 135                                  ocfs2_system_inodes[type].si_name,
 136                                  &ocfs2_sysfile_cluster_lock_key[type], 0);
 137         }
 138 #endif
 139 bail:
 140
 141         return inode;
 142 }