xref: /openbmc/linux/fs/jffs2/super.c (revision 9c261b33) 
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/parser.h>
21 #include <linux/jffs2.h>
22 #include <linux/pagemap.h>
23 #include <linux/mtd/super.h>
24 #include <linux/ctype.h>
25 #include <linux/namei.h>
26 #include <linux/seq_file.h>
27 #include <linux/exportfs.h>
28 #include "compr.h"
29 #include "nodelist.h"
30 
31 static void jffs2_put_super(struct super_block *);
32 
33 static struct kmem_cache *jffs2_inode_cachep;
34 
35 static struct inode *jffs2_alloc_inode(struct super_block *sb)
36 {
37 	struct jffs2_inode_info *f;
38 
39 	f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
40 	if (!f)
41 		return NULL;
42 	return &f->vfs_inode;
43 }
44 
45 static void jffs2_i_callback(struct rcu_head *head)
46 {
47 	struct inode *inode = container_of(head, struct inode, i_rcu);
48 	kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
49 }
50 
51 static void jffs2_destroy_inode(struct inode *inode)
52 {
53 	call_rcu(&inode->i_rcu, jffs2_i_callback);
54 }
55 
56 static void jffs2_i_init_once(void *foo)
57 {
58 	struct jffs2_inode_info *f = foo;
59 
60 	mutex_init(&f->sem);
61 	inode_init_once(&f->vfs_inode);
62 }
63 
64 static void jffs2_write_super(struct super_block *sb)
65 {
66 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
67 
68 	lock_super(sb);
69 	sb->s_dirt = 0;
70 
71 	if (!(sb->s_flags & MS_RDONLY)) {
72 		jffs2_dbg(1, "%s()\n", __func__);
73 		jffs2_flush_wbuf_gc(c, 0);
74 	}
75 
76 	unlock_super(sb);
77 }
78 
79 static const char *jffs2_compr_name(unsigned int compr)
80 {
81 	switch (compr) {
82 	case JFFS2_COMPR_MODE_NONE:
83 		return "none";
84 #ifdef CONFIG_JFFS2_LZO
85 	case JFFS2_COMPR_MODE_FORCELZO:
86 		return "lzo";
87 #endif
88 #ifdef CONFIG_JFFS2_ZLIB
89 	case JFFS2_COMPR_MODE_FORCEZLIB:
90 		return "zlib";
91 #endif
92 	default:
93 		/* should never happen; programmer error */
94 		WARN_ON(1);
95 		return "";
96 	}
97 }
98 
99 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
100 {
101 	struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
102 	struct jffs2_mount_opts *opts = &c->mount_opts;
103 
104 	if (opts->override_compr)
105 		seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
106 
107 	return 0;
108 }
109 
110 static int jffs2_sync_fs(struct super_block *sb, int wait)
111 {
112 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
113 
114 	jffs2_write_super(sb);
115 
116 	mutex_lock(&c->alloc_sem);
117 	jffs2_flush_wbuf_pad(c);
118 	mutex_unlock(&c->alloc_sem);
119 	return 0;
120 }
121 
122 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
123 					 uint32_t generation)
124 {
125 	/* We don't care about i_generation. We'll destroy the flash
126 	   before we start re-using inode numbers anyway. And even
127 	   if that wasn't true, we'd have other problems...*/
128 	return jffs2_iget(sb, ino);
129 }
130 
131 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
132 					 int fh_len, int fh_type)
133 {
134         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
135                                     jffs2_nfs_get_inode);
136 }
137 
138 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
139 					 int fh_len, int fh_type)
140 {
141         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
142                                     jffs2_nfs_get_inode);
143 }
144 
145 static struct dentry *jffs2_get_parent(struct dentry *child)
146 {
147 	struct jffs2_inode_info *f;
148 	uint32_t pino;
149 
150 	BUG_ON(!S_ISDIR(child->d_inode->i_mode));
151 
152 	f = JFFS2_INODE_INFO(child->d_inode);
153 
154 	pino = f->inocache->pino_nlink;
155 
156 	JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
157 		    f->inocache->ino, pino);
158 
159 	return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
160 }
161 
162 static const struct export_operations jffs2_export_ops = {
163 	.get_parent = jffs2_get_parent,
164 	.fh_to_dentry = jffs2_fh_to_dentry,
165 	.fh_to_parent = jffs2_fh_to_parent,
166 };
167 
168 /*
169  * JFFS2 mount options.
170  *
171  * Opt_override_compr: override default compressor
172  * Opt_err: just end of array marker
173  */
174 enum {
175 	Opt_override_compr,
176 	Opt_err,
177 };
178 
179 static const match_table_t tokens = {
180 	{Opt_override_compr, "compr=%s"},
181 	{Opt_err, NULL},
182 };
183 
184 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
185 {
186 	substring_t args[MAX_OPT_ARGS];
187 	char *p, *name;
188 
189 	if (!data)
190 		return 0;
191 
192 	while ((p = strsep(&data, ","))) {
193 		int token;
194 
195 		if (!*p)
196 			continue;
197 
198 		token = match_token(p, tokens, args);
199 		switch (token) {
200 		case Opt_override_compr:
201 			name = match_strdup(&args[0]);
202 
203 			if (!name)
204 				return -ENOMEM;
205 			if (!strcmp(name, "none"))
206 				c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
207 #ifdef CONFIG_JFFS2_LZO
208 			else if (!strcmp(name, "lzo"))
209 				c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
210 #endif
211 #ifdef CONFIG_JFFS2_ZLIB
212 			else if (!strcmp(name, "zlib"))
213 				c->mount_opts.compr =
214 						JFFS2_COMPR_MODE_FORCEZLIB;
215 #endif
216 			else {
217 				printk(KERN_ERR "JFFS2 Error: unknown compressor \"%s\"",
218 						name);
219 				kfree(name);
220 				return -EINVAL;
221 			}
222 			kfree(name);
223 			c->mount_opts.override_compr = true;
224 			break;
225 		default:
226 			printk(KERN_ERR "JFFS2 Error: unrecognized mount option '%s' or missing value\n",
227 					p);
228 			return -EINVAL;
229 		}
230 	}
231 
232 	return 0;
233 }
234 
235 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
236 {
237 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
238 	int err;
239 
240 	err = jffs2_parse_options(c, data);
241 	if (err)
242 		return -EINVAL;
243 
244 	return jffs2_do_remount_fs(sb, flags, data);
245 }
246 
247 static const struct super_operations jffs2_super_operations =
248 {
249 	.alloc_inode =	jffs2_alloc_inode,
250 	.destroy_inode =jffs2_destroy_inode,
251 	.put_super =	jffs2_put_super,
252 	.write_super =	jffs2_write_super,
253 	.statfs =	jffs2_statfs,
254 	.remount_fs =	jffs2_remount_fs,
255 	.evict_inode =	jffs2_evict_inode,
256 	.dirty_inode =	jffs2_dirty_inode,
257 	.show_options =	jffs2_show_options,
258 	.sync_fs =	jffs2_sync_fs,
259 };
260 
261 /*
262  * fill in the superblock
263  */
264 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
265 {
266 	struct jffs2_sb_info *c;
267 	int ret;
268 
269 	jffs2_dbg(1, "jffs2_get_sb_mtd():"
270 		  " New superblock for device %d (\"%s\")\n",
271 		  sb->s_mtd->index, sb->s_mtd->name);
272 
273 	c = kzalloc(sizeof(*c), GFP_KERNEL);
274 	if (!c)
275 		return -ENOMEM;
276 
277 	c->mtd = sb->s_mtd;
278 	c->os_priv = sb;
279 	sb->s_fs_info = c;
280 
281 	ret = jffs2_parse_options(c, data);
282 	if (ret) {
283 		kfree(c);
284 		return -EINVAL;
285 	}
286 
287 	/* Initialize JFFS2 superblock locks, the further initialization will
288 	 * be done later */
289 	mutex_init(&c->alloc_sem);
290 	mutex_init(&c->erase_free_sem);
291 	init_waitqueue_head(&c->erase_wait);
292 	init_waitqueue_head(&c->inocache_wq);
293 	spin_lock_init(&c->erase_completion_lock);
294 	spin_lock_init(&c->inocache_lock);
295 
296 	sb->s_op = &jffs2_super_operations;
297 	sb->s_export_op = &jffs2_export_ops;
298 	sb->s_flags = sb->s_flags | MS_NOATIME;
299 	sb->s_xattr = jffs2_xattr_handlers;
300 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
301 	sb->s_flags |= MS_POSIXACL;
302 #endif
303 	ret = jffs2_do_fill_super(sb, data, silent);
304 	return ret;
305 }
306 
307 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
308 			int flags, const char *dev_name,
309 			void *data)
310 {
311 	return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
312 }
313 
314 static void jffs2_put_super (struct super_block *sb)
315 {
316 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
317 
318 	jffs2_dbg(2, "%s()\n", __func__);
319 
320 	if (sb->s_dirt)
321 		jffs2_write_super(sb);
322 
323 	mutex_lock(&c->alloc_sem);
324 	jffs2_flush_wbuf_pad(c);
325 	mutex_unlock(&c->alloc_sem);
326 
327 	jffs2_sum_exit(c);
328 
329 	jffs2_free_ino_caches(c);
330 	jffs2_free_raw_node_refs(c);
331 	if (jffs2_blocks_use_vmalloc(c))
332 		vfree(c->blocks);
333 	else
334 		kfree(c->blocks);
335 	jffs2_flash_cleanup(c);
336 	kfree(c->inocache_list);
337 	jffs2_clear_xattr_subsystem(c);
338 	mtd_sync(c->mtd);
339 	jffs2_dbg(1, "%s(): returning\n", __func__);
340 }
341 
342 static void jffs2_kill_sb(struct super_block *sb)
343 {
344 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
345 	if (!(sb->s_flags & MS_RDONLY))
346 		jffs2_stop_garbage_collect_thread(c);
347 	kill_mtd_super(sb);
348 	kfree(c);
349 }
350 
351 static struct file_system_type jffs2_fs_type = {
352 	.owner =	THIS_MODULE,
353 	.name =		"jffs2",
354 	.mount =	jffs2_mount,
355 	.kill_sb =	jffs2_kill_sb,
356 };
357 
358 static int __init init_jffs2_fs(void)
359 {
360 	int ret;
361 
362 	/* Paranoia checks for on-medium structures. If we ask GCC
363 	   to pack them with __attribute__((packed)) then it _also_
364 	   assumes that they're not aligned -- so it emits crappy
365 	   code on some architectures. Ideally we want an attribute
366 	   which means just 'no padding', without the alignment
367 	   thing. But GCC doesn't have that -- we have to just
368 	   hope the structs are the right sizes, instead. */
369 	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
370 	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
371 	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
372 	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
373 
374 	printk(KERN_INFO "JFFS2 version 2.2."
375 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
376 	       " (NAND)"
377 #endif
378 #ifdef CONFIG_JFFS2_SUMMARY
379 	       " (SUMMARY) "
380 #endif
381 	       " © 2001-2006 Red Hat, Inc.\n");
382 
383 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
384 					     sizeof(struct jffs2_inode_info),
385 					     0, (SLAB_RECLAIM_ACCOUNT|
386 						SLAB_MEM_SPREAD),
387 					     jffs2_i_init_once);
388 	if (!jffs2_inode_cachep) {
389 		printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
390 		return -ENOMEM;
391 	}
392 	ret = jffs2_compressors_init();
393 	if (ret) {
394 		printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
395 		goto out;
396 	}
397 	ret = jffs2_create_slab_caches();
398 	if (ret) {
399 		printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
400 		goto out_compressors;
401 	}
402 	ret = register_filesystem(&jffs2_fs_type);
403 	if (ret) {
404 		printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
405 		goto out_slab;
406 	}
407 	return 0;
408 
409  out_slab:
410 	jffs2_destroy_slab_caches();
411  out_compressors:
412 	jffs2_compressors_exit();
413  out:
414 	kmem_cache_destroy(jffs2_inode_cachep);
415 	return ret;
416 }
417 
418 static void __exit exit_jffs2_fs(void)
419 {
420 	unregister_filesystem(&jffs2_fs_type);
421 	jffs2_destroy_slab_caches();
422 	jffs2_compressors_exit();
423 	kmem_cache_destroy(jffs2_inode_cachep);
424 }
425 
426 module_init(init_jffs2_fs);
427 module_exit(exit_jffs2_fs);
428 
429 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
430 MODULE_AUTHOR("Red Hat, Inc.");
431 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
432 		       // the sake of this tag. It's Free Software.
433