xref: /openbmc/linux/fs/jffs2/super.c (revision 565d76cb)
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright © 2001-2007 Red Hat, Inc.
5  *
6  * Created by David Woodhouse <dwmw2@infradead.org>
7  *
8  * For licensing information, see the file 'LICENCE' in this directory.
9  *
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/init.h>
16 #include <linux/list.h>
17 #include <linux/fs.h>
18 #include <linux/err.h>
19 #include <linux/mount.h>
20 #include <linux/jffs2.h>
21 #include <linux/pagemap.h>
22 #include <linux/mtd/super.h>
23 #include <linux/ctype.h>
24 #include <linux/namei.h>
25 #include <linux/exportfs.h>
26 #include "compr.h"
27 #include "nodelist.h"
28 
29 static void jffs2_put_super(struct super_block *);
30 
31 static struct kmem_cache *jffs2_inode_cachep;
32 
33 static struct inode *jffs2_alloc_inode(struct super_block *sb)
34 {
35 	struct jffs2_inode_info *f;
36 
37 	f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
38 	if (!f)
39 		return NULL;
40 	return &f->vfs_inode;
41 }
42 
43 static void jffs2_i_callback(struct rcu_head *head)
44 {
45 	struct inode *inode = container_of(head, struct inode, i_rcu);
46 	INIT_LIST_HEAD(&inode->i_dentry);
47 	kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
48 }
49 
50 static void jffs2_destroy_inode(struct inode *inode)
51 {
52 	call_rcu(&inode->i_rcu, jffs2_i_callback);
53 }
54 
55 static void jffs2_i_init_once(void *foo)
56 {
57 	struct jffs2_inode_info *f = foo;
58 
59 	mutex_init(&f->sem);
60 	inode_init_once(&f->vfs_inode);
61 }
62 
63 static void jffs2_write_super(struct super_block *sb)
64 {
65 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
66 
67 	lock_super(sb);
68 	sb->s_dirt = 0;
69 
70 	if (!(sb->s_flags & MS_RDONLY)) {
71 		D1(printk(KERN_DEBUG "jffs2_write_super()\n"));
72 		jffs2_flush_wbuf_gc(c, 0);
73 	}
74 
75 	unlock_super(sb);
76 }
77 
78 static int jffs2_sync_fs(struct super_block *sb, int wait)
79 {
80 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
81 
82 	jffs2_write_super(sb);
83 
84 	mutex_lock(&c->alloc_sem);
85 	jffs2_flush_wbuf_pad(c);
86 	mutex_unlock(&c->alloc_sem);
87 	return 0;
88 }
89 
90 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
91 					 uint32_t generation)
92 {
93 	/* We don't care about i_generation. We'll destroy the flash
94 	   before we start re-using inode numbers anyway. And even
95 	   if that wasn't true, we'd have other problems...*/
96 	return jffs2_iget(sb, ino);
97 }
98 
99 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
100 					 int fh_len, int fh_type)
101 {
102         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
103                                     jffs2_nfs_get_inode);
104 }
105 
106 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
107 					 int fh_len, int fh_type)
108 {
109         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
110                                     jffs2_nfs_get_inode);
111 }
112 
113 static struct dentry *jffs2_get_parent(struct dentry *child)
114 {
115 	struct jffs2_inode_info *f;
116 	uint32_t pino;
117 
118 	BUG_ON(!S_ISDIR(child->d_inode->i_mode));
119 
120 	f = JFFS2_INODE_INFO(child->d_inode);
121 
122 	pino = f->inocache->pino_nlink;
123 
124 	JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
125 		    f->inocache->ino, pino);
126 
127 	return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
128 }
129 
130 static const struct export_operations jffs2_export_ops = {
131 	.get_parent = jffs2_get_parent,
132 	.fh_to_dentry = jffs2_fh_to_dentry,
133 	.fh_to_parent = jffs2_fh_to_parent,
134 };
135 
136 static const struct super_operations jffs2_super_operations =
137 {
138 	.alloc_inode =	jffs2_alloc_inode,
139 	.destroy_inode =jffs2_destroy_inode,
140 	.put_super =	jffs2_put_super,
141 	.write_super =	jffs2_write_super,
142 	.statfs =	jffs2_statfs,
143 	.remount_fs =	jffs2_remount_fs,
144 	.evict_inode =	jffs2_evict_inode,
145 	.dirty_inode =	jffs2_dirty_inode,
146 	.sync_fs =	jffs2_sync_fs,
147 };
148 
149 /*
150  * fill in the superblock
151  */
152 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
153 {
154 	struct jffs2_sb_info *c;
155 	int ret;
156 
157 	D1(printk(KERN_DEBUG "jffs2_get_sb_mtd():"
158 		  " New superblock for device %d (\"%s\")\n",
159 		  sb->s_mtd->index, sb->s_mtd->name));
160 
161 	c = kzalloc(sizeof(*c), GFP_KERNEL);
162 	if (!c)
163 		return -ENOMEM;
164 
165 	c->mtd = sb->s_mtd;
166 	c->os_priv = sb;
167 	sb->s_fs_info = c;
168 
169 	/* Initialize JFFS2 superblock locks, the further initialization will
170 	 * be done later */
171 	mutex_init(&c->alloc_sem);
172 	mutex_init(&c->erase_free_sem);
173 	init_waitqueue_head(&c->erase_wait);
174 	init_waitqueue_head(&c->inocache_wq);
175 	spin_lock_init(&c->erase_completion_lock);
176 	spin_lock_init(&c->inocache_lock);
177 
178 	sb->s_op = &jffs2_super_operations;
179 	sb->s_export_op = &jffs2_export_ops;
180 	sb->s_flags = sb->s_flags | MS_NOATIME;
181 	sb->s_xattr = jffs2_xattr_handlers;
182 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
183 	sb->s_flags |= MS_POSIXACL;
184 #endif
185 	ret = jffs2_do_fill_super(sb, data, silent);
186 	return ret;
187 }
188 
189 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
190 			int flags, const char *dev_name,
191 			void *data)
192 {
193 	return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
194 }
195 
196 static void jffs2_put_super (struct super_block *sb)
197 {
198 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
199 
200 	D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
201 
202 	if (sb->s_dirt)
203 		jffs2_write_super(sb);
204 
205 	mutex_lock(&c->alloc_sem);
206 	jffs2_flush_wbuf_pad(c);
207 	mutex_unlock(&c->alloc_sem);
208 
209 	jffs2_sum_exit(c);
210 
211 	jffs2_free_ino_caches(c);
212 	jffs2_free_raw_node_refs(c);
213 	if (jffs2_blocks_use_vmalloc(c))
214 		vfree(c->blocks);
215 	else
216 		kfree(c->blocks);
217 	jffs2_flash_cleanup(c);
218 	kfree(c->inocache_list);
219 	jffs2_clear_xattr_subsystem(c);
220 	if (c->mtd->sync)
221 		c->mtd->sync(c->mtd);
222 
223 	D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
224 }
225 
226 static void jffs2_kill_sb(struct super_block *sb)
227 {
228 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
229 	if (!(sb->s_flags & MS_RDONLY))
230 		jffs2_stop_garbage_collect_thread(c);
231 	kill_mtd_super(sb);
232 	kfree(c);
233 }
234 
235 static struct file_system_type jffs2_fs_type = {
236 	.owner =	THIS_MODULE,
237 	.name =		"jffs2",
238 	.mount =	jffs2_mount,
239 	.kill_sb =	jffs2_kill_sb,
240 };
241 
242 static int __init init_jffs2_fs(void)
243 {
244 	int ret;
245 
246 	/* Paranoia checks for on-medium structures. If we ask GCC
247 	   to pack them with __attribute__((packed)) then it _also_
248 	   assumes that they're not aligned -- so it emits crappy
249 	   code on some architectures. Ideally we want an attribute
250 	   which means just 'no padding', without the alignment
251 	   thing. But GCC doesn't have that -- we have to just
252 	   hope the structs are the right sizes, instead. */
253 	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
254 	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
255 	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
256 	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
257 
258 	printk(KERN_INFO "JFFS2 version 2.2."
259 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
260 	       " (NAND)"
261 #endif
262 #ifdef CONFIG_JFFS2_SUMMARY
263 	       " (SUMMARY) "
264 #endif
265 	       " © 2001-2006 Red Hat, Inc.\n");
266 
267 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
268 					     sizeof(struct jffs2_inode_info),
269 					     0, (SLAB_RECLAIM_ACCOUNT|
270 						SLAB_MEM_SPREAD),
271 					     jffs2_i_init_once);
272 	if (!jffs2_inode_cachep) {
273 		printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
274 		return -ENOMEM;
275 	}
276 	ret = jffs2_compressors_init();
277 	if (ret) {
278 		printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
279 		goto out;
280 	}
281 	ret = jffs2_create_slab_caches();
282 	if (ret) {
283 		printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
284 		goto out_compressors;
285 	}
286 	ret = register_filesystem(&jffs2_fs_type);
287 	if (ret) {
288 		printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
289 		goto out_slab;
290 	}
291 	return 0;
292 
293  out_slab:
294 	jffs2_destroy_slab_caches();
295  out_compressors:
296 	jffs2_compressors_exit();
297  out:
298 	kmem_cache_destroy(jffs2_inode_cachep);
299 	return ret;
300 }
301 
302 static void __exit exit_jffs2_fs(void)
303 {
304 	unregister_filesystem(&jffs2_fs_type);
305 	jffs2_destroy_slab_caches();
306 	jffs2_compressors_exit();
307 	kmem_cache_destroy(jffs2_inode_cachep);
308 }
309 
310 module_init(init_jffs2_fs);
311 module_exit(exit_jffs2_fs);
312 
313 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
314 MODULE_AUTHOR("Red Hat, Inc.");
315 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
316 		       // the sake of this tag. It's Free Software.
317