xref: /openbmc/linux/fs/jffs2/super.c (revision 58fc7f73)
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/init.h>
18 #include <linux/list.h>
19 #include <linux/fs.h>
20 #include <linux/err.h>
21 #include <linux/mount.h>
22 #include <linux/parser.h>
23 #include <linux/jffs2.h>
24 #include <linux/pagemap.h>
25 #include <linux/mtd/super.h>
26 #include <linux/ctype.h>
27 #include <linux/namei.h>
28 #include <linux/seq_file.h>
29 #include <linux/exportfs.h>
30 #include "compr.h"
31 #include "nodelist.h"
32 
33 static void jffs2_put_super(struct super_block *);
34 
35 static struct kmem_cache *jffs2_inode_cachep;
36 
37 static struct inode *jffs2_alloc_inode(struct super_block *sb)
38 {
39 	struct jffs2_inode_info *f;
40 
41 	f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
42 	if (!f)
43 		return NULL;
44 	return &f->vfs_inode;
45 }
46 
47 static void jffs2_i_callback(struct rcu_head *head)
48 {
49 	struct inode *inode = container_of(head, struct inode, i_rcu);
50 	kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
51 }
52 
53 static void jffs2_destroy_inode(struct inode *inode)
54 {
55 	call_rcu(&inode->i_rcu, jffs2_i_callback);
56 }
57 
58 static void jffs2_i_init_once(void *foo)
59 {
60 	struct jffs2_inode_info *f = foo;
61 
62 	mutex_init(&f->sem);
63 	inode_init_once(&f->vfs_inode);
64 }
65 
66 static const char *jffs2_compr_name(unsigned int compr)
67 {
68 	switch (compr) {
69 	case JFFS2_COMPR_MODE_NONE:
70 		return "none";
71 #ifdef CONFIG_JFFS2_LZO
72 	case JFFS2_COMPR_MODE_FORCELZO:
73 		return "lzo";
74 #endif
75 #ifdef CONFIG_JFFS2_ZLIB
76 	case JFFS2_COMPR_MODE_FORCEZLIB:
77 		return "zlib";
78 #endif
79 	default:
80 		/* should never happen; programmer error */
81 		WARN_ON(1);
82 		return "";
83 	}
84 }
85 
86 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
87 {
88 	struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
89 	struct jffs2_mount_opts *opts = &c->mount_opts;
90 
91 	if (opts->override_compr)
92 		seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
93 	if (opts->rp_size)
94 		seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
95 
96 	return 0;
97 }
98 
99 static int jffs2_sync_fs(struct super_block *sb, int wait)
100 {
101 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
102 
103 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
104 	cancel_delayed_work_sync(&c->wbuf_dwork);
105 #endif
106 
107 	mutex_lock(&c->alloc_sem);
108 	jffs2_flush_wbuf_pad(c);
109 	mutex_unlock(&c->alloc_sem);
110 	return 0;
111 }
112 
113 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
114 					 uint32_t generation)
115 {
116 	/* We don't care about i_generation. We'll destroy the flash
117 	   before we start re-using inode numbers anyway. And even
118 	   if that wasn't true, we'd have other problems...*/
119 	return jffs2_iget(sb, ino);
120 }
121 
122 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
123 					 int fh_len, int fh_type)
124 {
125         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
126                                     jffs2_nfs_get_inode);
127 }
128 
129 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
130 					 int fh_len, int fh_type)
131 {
132         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
133                                     jffs2_nfs_get_inode);
134 }
135 
136 static struct dentry *jffs2_get_parent(struct dentry *child)
137 {
138 	struct jffs2_inode_info *f;
139 	uint32_t pino;
140 
141 	BUG_ON(!d_is_dir(child));
142 
143 	f = JFFS2_INODE_INFO(d_inode(child));
144 
145 	pino = f->inocache->pino_nlink;
146 
147 	JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
148 		    f->inocache->ino, pino);
149 
150 	return d_obtain_alias(jffs2_iget(child->d_sb, pino));
151 }
152 
153 static const struct export_operations jffs2_export_ops = {
154 	.get_parent = jffs2_get_parent,
155 	.fh_to_dentry = jffs2_fh_to_dentry,
156 	.fh_to_parent = jffs2_fh_to_parent,
157 };
158 
159 /*
160  * JFFS2 mount options.
161  *
162  * Opt_override_compr: override default compressor
163  * Opt_rp_size: size of reserved pool in KiB
164  * Opt_err: just end of array marker
165  */
166 enum {
167 	Opt_override_compr,
168 	Opt_rp_size,
169 	Opt_err,
170 };
171 
172 static const match_table_t tokens = {
173 	{Opt_override_compr, "compr=%s"},
174 	{Opt_rp_size, "rp_size=%u"},
175 	{Opt_err, NULL},
176 };
177 
178 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
179 {
180 	substring_t args[MAX_OPT_ARGS];
181 	char *p, *name;
182 	unsigned int opt;
183 
184 	if (!data)
185 		return 0;
186 
187 	while ((p = strsep(&data, ","))) {
188 		int token;
189 
190 		if (!*p)
191 			continue;
192 
193 		token = match_token(p, tokens, args);
194 		switch (token) {
195 		case Opt_override_compr:
196 			name = match_strdup(&args[0]);
197 
198 			if (!name)
199 				return -ENOMEM;
200 			if (!strcmp(name, "none"))
201 				c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
202 #ifdef CONFIG_JFFS2_LZO
203 			else if (!strcmp(name, "lzo"))
204 				c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
205 #endif
206 #ifdef CONFIG_JFFS2_ZLIB
207 			else if (!strcmp(name, "zlib"))
208 				c->mount_opts.compr =
209 						JFFS2_COMPR_MODE_FORCEZLIB;
210 #endif
211 			else {
212 				pr_err("Error: unknown compressor \"%s\"\n",
213 				       name);
214 				kfree(name);
215 				return -EINVAL;
216 			}
217 			kfree(name);
218 			c->mount_opts.override_compr = true;
219 			break;
220 		case Opt_rp_size:
221 			if (match_int(&args[0], &opt))
222 				return -EINVAL;
223 			opt *= 1024;
224 			if (opt > c->mtd->size) {
225 				pr_warn("Too large reserve pool specified, max "
226 					"is %llu KB\n", c->mtd->size / 1024);
227 				return -EINVAL;
228 			}
229 			c->mount_opts.rp_size = opt;
230 			break;
231 		default:
232 			pr_err("Error: unrecognized mount option '%s' or missing value\n",
233 			       p);
234 			return -EINVAL;
235 		}
236 	}
237 
238 	return 0;
239 }
240 
241 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
242 {
243 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
244 	int err;
245 
246 	sync_filesystem(sb);
247 	err = jffs2_parse_options(c, data);
248 	if (err)
249 		return -EINVAL;
250 
251 	return jffs2_do_remount_fs(sb, flags, data);
252 }
253 
254 static const struct super_operations jffs2_super_operations =
255 {
256 	.alloc_inode =	jffs2_alloc_inode,
257 	.destroy_inode =jffs2_destroy_inode,
258 	.put_super =	jffs2_put_super,
259 	.statfs =	jffs2_statfs,
260 	.remount_fs =	jffs2_remount_fs,
261 	.evict_inode =	jffs2_evict_inode,
262 	.dirty_inode =	jffs2_dirty_inode,
263 	.show_options =	jffs2_show_options,
264 	.sync_fs =	jffs2_sync_fs,
265 };
266 
267 /*
268  * fill in the superblock
269  */
270 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
271 {
272 	struct jffs2_sb_info *c;
273 	int ret;
274 
275 	jffs2_dbg(1, "jffs2_get_sb_mtd():"
276 		  " New superblock for device %d (\"%s\")\n",
277 		  sb->s_mtd->index, sb->s_mtd->name);
278 
279 	c = kzalloc(sizeof(*c), GFP_KERNEL);
280 	if (!c)
281 		return -ENOMEM;
282 
283 	c->mtd = sb->s_mtd;
284 	c->os_priv = sb;
285 	sb->s_fs_info = c;
286 
287 	ret = jffs2_parse_options(c, data);
288 	if (ret) {
289 		kfree(c);
290 		return -EINVAL;
291 	}
292 
293 	/* Initialize JFFS2 superblock locks, the further initialization will
294 	 * be done later */
295 	mutex_init(&c->alloc_sem);
296 	mutex_init(&c->erase_free_sem);
297 	init_waitqueue_head(&c->erase_wait);
298 	init_waitqueue_head(&c->inocache_wq);
299 	spin_lock_init(&c->erase_completion_lock);
300 	spin_lock_init(&c->inocache_lock);
301 
302 	sb->s_op = &jffs2_super_operations;
303 	sb->s_export_op = &jffs2_export_ops;
304 	sb->s_flags = sb->s_flags | MS_NOATIME;
305 	sb->s_xattr = jffs2_xattr_handlers;
306 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
307 	sb->s_flags |= MS_POSIXACL;
308 #endif
309 	ret = jffs2_do_fill_super(sb, data, silent);
310 	return ret;
311 }
312 
313 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
314 			int flags, const char *dev_name,
315 			void *data)
316 {
317 	return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
318 }
319 
320 static void jffs2_put_super (struct super_block *sb)
321 {
322 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
323 
324 	jffs2_dbg(2, "%s()\n", __func__);
325 
326 	mutex_lock(&c->alloc_sem);
327 	jffs2_flush_wbuf_pad(c);
328 	mutex_unlock(&c->alloc_sem);
329 
330 	jffs2_sum_exit(c);
331 
332 	jffs2_free_ino_caches(c);
333 	jffs2_free_raw_node_refs(c);
334 	kvfree(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_rdonly(sb))
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 MODULE_ALIAS_FS("jffs2");
358 
359 static int __init init_jffs2_fs(void)
360 {
361 	int ret;
362 
363 	/* Paranoia checks for on-medium structures. If we ask GCC
364 	   to pack them with __attribute__((packed)) then it _also_
365 	   assumes that they're not aligned -- so it emits crappy
366 	   code on some architectures. Ideally we want an attribute
367 	   which means just 'no padding', without the alignment
368 	   thing. But GCC doesn't have that -- we have to just
369 	   hope the structs are the right sizes, instead. */
370 	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
371 	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
372 	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
373 	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
374 
375 	pr_info("version 2.2."
376 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
377 	       " (NAND)"
378 #endif
379 #ifdef CONFIG_JFFS2_SUMMARY
380 	       " (SUMMARY) "
381 #endif
382 	       " © 2001-2006 Red Hat, Inc.\n");
383 
384 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
385 					     sizeof(struct jffs2_inode_info),
386 					     0, (SLAB_RECLAIM_ACCOUNT|
387 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
388 					     jffs2_i_init_once);
389 	if (!jffs2_inode_cachep) {
390 		pr_err("error: Failed to initialise inode cache\n");
391 		return -ENOMEM;
392 	}
393 	ret = jffs2_compressors_init();
394 	if (ret) {
395 		pr_err("error: Failed to initialise compressors\n");
396 		goto out;
397 	}
398 	ret = jffs2_create_slab_caches();
399 	if (ret) {
400 		pr_err("error: Failed to initialise slab caches\n");
401 		goto out_compressors;
402 	}
403 	ret = register_filesystem(&jffs2_fs_type);
404 	if (ret) {
405 		pr_err("error: Failed to register filesystem\n");
406 		goto out_slab;
407 	}
408 	return 0;
409 
410  out_slab:
411 	jffs2_destroy_slab_caches();
412  out_compressors:
413 	jffs2_compressors_exit();
414  out:
415 	kmem_cache_destroy(jffs2_inode_cachep);
416 	return ret;
417 }
418 
419 static void __exit exit_jffs2_fs(void)
420 {
421 	unregister_filesystem(&jffs2_fs_type);
422 	jffs2_destroy_slab_caches();
423 	jffs2_compressors_exit();
424 
425 	/*
426 	 * Make sure all delayed rcu free inodes are flushed before we
427 	 * destroy cache.
428 	 */
429 	rcu_barrier();
430 	kmem_cache_destroy(jffs2_inode_cachep);
431 }
432 
433 module_init(init_jffs2_fs);
434 module_exit(exit_jffs2_fs);
435 
436 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
437 MODULE_AUTHOR("Red Hat, Inc.");
438 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
439 		       // the sake of this tag. It's Free Software.
440