xref: /linux/fs/ocfs2/sysfile.c (revision c4ee0af3fa0dc65f690fc908f02b8355f9576ea0)
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 	if (arr && ((inode = *arr) != NULL)) {
117 		/* get a ref in addition to the array ref */
118 		inode = igrab(inode);
119 		BUG_ON(!inode);
120 
121 		return inode;
122 	}
123 
124 	/* this gets one ref thru iget */
125 	inode = _ocfs2_get_system_file_inode(osb, type, slot);
126 
127 	/* add one more if putting into array for first time */
128 	if (arr && inode) {
129 		*arr = igrab(inode);
130 		BUG_ON(!*arr);
131 	}
132 	return inode;
133 }
134 
135 static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
136 						   int type,
137 						   u32 slot)
138 {
139 	char namebuf[40];
140 	struct inode *inode = NULL;
141 	u64 blkno;
142 	int status = 0;
143 
144 	ocfs2_sprintf_system_inode_name(namebuf,
145 					sizeof(namebuf),
146 					type, slot);
147 
148 	status = ocfs2_lookup_ino_from_name(osb->sys_root_inode, namebuf,
149 					    strlen(namebuf), &blkno);
150 	if (status < 0) {
151 		goto bail;
152 	}
153 
154 	inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE, type);
155 	if (IS_ERR(inode)) {
156 		mlog_errno(PTR_ERR(inode));
157 		inode = NULL;
158 		goto bail;
159 	}
160 #ifdef CONFIG_DEBUG_LOCK_ALLOC
161 	if (type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
162 	    type == LOCAL_GROUP_QUOTA_SYSTEM_INODE ||
163 	    type == JOURNAL_SYSTEM_INODE) {
164 		/* Ignore inode lock on these inodes as the lock does not
165 		 * really belong to any process and lockdep cannot handle
166 		 * that */
167 		OCFS2_I(inode)->ip_inode_lockres.l_lockdep_map.key = NULL;
168 	} else {
169 		lockdep_init_map(&OCFS2_I(inode)->ip_inode_lockres.
170 								l_lockdep_map,
171 				 ocfs2_system_inodes[type].si_name,
172 				 &ocfs2_sysfile_cluster_lock_key[type], 0);
173 	}
174 #endif
175 bail:
176 
177 	return inode;
178 }
179 
180