Root/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
42static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
43                           int type,
44                           u32 slot);
45
46#ifdef CONFIG_DEBUG_LOCK_ALLOC
47static struct lock_class_key ocfs2_sysfile_cluster_lock_key[NUM_SYSTEM_INODES];
48#endif
49
50static 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
56static 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        if (unlikely(free))
95            kfree(free);
96    }
97
98    index = (slot * NUM_LOCAL_SYSTEM_INODES) +
99        (type - OCFS2_FIRST_LOCAL_SYSTEM_INODE);
100
101    return &local_system_inodes[index];
102}
103
104struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb,
105                      int type,
106                      u32 slot)
107{
108    struct inode *inode = NULL;
109    struct inode **arr = NULL;
110
111    /* avoid the lookup if cached in local system file array */
112    if (is_global_system_inode(type)) {
113        arr = &(osb->global_system_inodes[type]);
114    } else
115        arr = get_local_system_inode(osb, type, slot);
116
117    if (arr && ((inode = *arr) != NULL)) {
118        /* get a ref in addition to the array ref */
119        inode = igrab(inode);
120        BUG_ON(!inode);
121
122        return inode;
123    }
124
125    /* this gets one ref thru iget */
126    inode = _ocfs2_get_system_file_inode(osb, type, slot);
127
128    /* add one more if putting into array for first time */
129    if (arr && inode) {
130        *arr = igrab(inode);
131        BUG_ON(!*arr);
132    }
133    return inode;
134}
135
136static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
137                           int type,
138                           u32 slot)
139{
140    char namebuf[40];
141    struct inode *inode = NULL;
142    u64 blkno;
143    int status = 0;
144
145    ocfs2_sprintf_system_inode_name(namebuf,
146                    sizeof(namebuf),
147                    type, slot);
148
149    status = ocfs2_lookup_ino_from_name(osb->sys_root_inode, namebuf,
150                        strlen(namebuf), &blkno);
151    if (status < 0) {
152        goto bail;
153    }
154
155    inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE, type);
156    if (IS_ERR(inode)) {
157        mlog_errno(PTR_ERR(inode));
158        inode = NULL;
159        goto bail;
160    }
161#ifdef CONFIG_DEBUG_LOCK_ALLOC
162    if (type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
163        type == LOCAL_GROUP_QUOTA_SYSTEM_INODE ||
164        type == JOURNAL_SYSTEM_INODE) {
165        /* Ignore inode lock on these inodes as the lock does not
166         * really belong to any process and lockdep cannot handle
167         * that */
168        OCFS2_I(inode)->ip_inode_lockres.l_lockdep_map.key = NULL;
169    } else {
170        lockdep_init_map(&OCFS2_I(inode)->ip_inode_lockres.
171                                l_lockdep_map,
172                 ocfs2_system_inodes[type].si_name,
173                 &ocfs2_sysfile_cluster_lock_key[type], 0);
174    }
175#endif
176bail:
177
178    return inode;
179}
180
181

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