release/src-rt-6.x/linux/linux-2.6/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/slab.h>
  29 #include <linux/highmem.h>
  30
  31 #define MLOG_MASK_PREFIX ML_INODE
  32 #include <cluster/masklog.h>
  33
  34 #include "ocfs2.h"
  35
  36 #include "alloc.h"
  37 #include "dir.h"
  38 #include "inode.h"
  39 #include "journal.h"
  40 #include "sysfile.h"
  41
  42 #include "buffer_head_io.h"
  43
  44 static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  45                                                    int type,
  46                                                    u32 slot);
  47
  48 static inline int is_global_system_inode(int type);
  49 static inline int is_in_system_inode_array(struct ocfs2_super *osb,
  50                                            int type,
  51                                            u32 slot);
  52
  53 static inline int is_global_system_inode(int type)
  54 {
  55         return type >= OCFS2_FIRST_ONLINE_SYSTEM_INODE &&
  56                 type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE;
  57 }
  58
  59 static inline int is_in_system_inode_array(struct ocfs2_super *osb,
  60                                            int type,
  61                                            u32 slot)
  62 {
  63         return slot == osb->slot_num || is_global_system_inode(type);
  64 }
  65
  66 struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  67                                           int type,
  68                                           u32 slot)
  69 {
  70         struct inode *inode = NULL;
  71         struct inode **arr = NULL;
  72
  73         /* avoid the lookup if cached in local system file array */
  74         if (is_in_system_inode_array(osb, type, slot))
  75                 arr = &(osb->system_inodes[type]);
  76
  77         if (arr && ((inode = *arr) != NULL)) {
  78                 /* get a ref in addition to the array ref */
  79                 inode = igrab(inode);
  80                 BUG_ON(!inode);
  81
  82                 return inode;
  83         }
  84
  85         /* this gets one ref thru iget */
  86         inode = _ocfs2_get_system_file_inode(osb, type, slot);
  87
  88         /* add one more if putting into array for first time */
  89         if (arr && inode) {
  90                 *arr = igrab(inode);
  91                 BUG_ON(!*arr);
  92         }
  93         return inode;
  94 }
  95
  96 static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
  97                                                    int type,
  98                                                    u32 slot)
  99 {
 100         char namebuf[40];
 101         struct inode *inode = NULL;
 102         u64 blkno;
 103         struct buffer_head *dirent_bh = NULL;
 104         struct ocfs2_dir_entry *de = NULL;
 105         int status = 0;
 106
 107         ocfs2_sprintf_system_inode_name(namebuf,
 108                                         sizeof(namebuf),
 109                                         type, slot);
 110
 111         status = ocfs2_find_files_on_disk(namebuf, strlen(namebuf),
 112                                           &blkno, osb->sys_root_inode,
 113                                           &dirent_bh, &de);
 114         if (status < 0) {
 115                 goto bail;
 116         }
 117
 118         inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE);
 119         if (IS_ERR(inode)) {
 120                 mlog_errno(PTR_ERR(inode));
 121                 inode = NULL;
 122                 goto bail;
 123         }
 124 bail:
 125         if (dirent_bh)
 126                 brelse(dirent_bh);
 127         return inode;
 128 }
 129