xref: /linux/fs/jffs2/super.c (revision f86fd32d) 
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/fs_context.h>
23 #include <linux/fs_parser.h>
24 #include <linux/jffs2.h>
25 #include <linux/pagemap.h>
26 #include <linux/mtd/super.h>
27 #include <linux/ctype.h>
28 #include <linux/namei.h>
29 #include <linux/seq_file.h>
30 #include <linux/exportfs.h>
31 #include "compr.h"
32 #include "nodelist.h"
33 
34 static void jffs2_put_super(struct super_block *);
35 
36 static struct kmem_cache *jffs2_inode_cachep;
37 
38 static struct inode *jffs2_alloc_inode(struct super_block *sb)
39 {
40 	struct jffs2_inode_info *f;
41 
42 	f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
43 	if (!f)
44 		return NULL;
45 	return &f->vfs_inode;
46 }
47 
48 static void jffs2_free_inode(struct inode *inode)
49 {
50 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
51 
52 	kfree(f->target);
53 	kmem_cache_free(jffs2_inode_cachep, f);
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 const char *jffs2_compr_name(unsigned int compr)
65 {
66 	switch (compr) {
67 	case JFFS2_COMPR_MODE_NONE:
68 		return "none";
69 #ifdef CONFIG_JFFS2_LZO
70 	case JFFS2_COMPR_MODE_FORCELZO:
71 		return "lzo";
72 #endif
73 #ifdef CONFIG_JFFS2_ZLIB
74 	case JFFS2_COMPR_MODE_FORCEZLIB:
75 		return "zlib";
76 #endif
77 	default:
78 		/* should never happen; programmer error */
79 		WARN_ON(1);
80 		return "";
81 	}
82 }
83 
84 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
85 {
86 	struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
87 	struct jffs2_mount_opts *opts = &c->mount_opts;
88 
89 	if (opts->override_compr)
90 		seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
91 	if (opts->rp_size)
92 		seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
93 
94 	return 0;
95 }
96 
97 static int jffs2_sync_fs(struct super_block *sb, int wait)
98 {
99 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
100 
101 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
102 	if (jffs2_is_writebuffered(c))
103 		cancel_delayed_work_sync(&c->wbuf_dwork);
104 #endif
105 
106 	mutex_lock(&c->alloc_sem);
107 	jffs2_flush_wbuf_pad(c);
108 	mutex_unlock(&c->alloc_sem);
109 	return 0;
110 }
111 
112 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
113 					 uint32_t generation)
114 {
115 	/* We don't care about i_generation. We'll destroy the flash
116 	   before we start re-using inode numbers anyway. And even
117 	   if that wasn't true, we'd have other problems...*/
118 	return jffs2_iget(sb, ino);
119 }
120 
121 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
122 					 int fh_len, int fh_type)
123 {
124         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
125                                     jffs2_nfs_get_inode);
126 }
127 
128 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
129 					 int fh_len, int fh_type)
130 {
131         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
132                                     jffs2_nfs_get_inode);
133 }
134 
135 static struct dentry *jffs2_get_parent(struct dentry *child)
136 {
137 	struct jffs2_inode_info *f;
138 	uint32_t pino;
139 
140 	BUG_ON(!d_is_dir(child));
141 
142 	f = JFFS2_INODE_INFO(d_inode(child));
143 
144 	pino = f->inocache->pino_nlink;
145 
146 	JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
147 		    f->inocache->ino, pino);
148 
149 	return d_obtain_alias(jffs2_iget(child->d_sb, pino));
150 }
151 
152 static const struct export_operations jffs2_export_ops = {
153 	.get_parent = jffs2_get_parent,
154 	.fh_to_dentry = jffs2_fh_to_dentry,
155 	.fh_to_parent = jffs2_fh_to_parent,
156 };
157 
158 /*
159  * JFFS2 mount options.
160  *
161  * Opt_source: The source device
162  * Opt_override_compr: override default compressor
163  * Opt_rp_size: size of reserved pool in KiB
164  */
165 enum {
166 	Opt_override_compr,
167 	Opt_rp_size,
168 };
169 
170 static const struct constant_table jffs2_param_compr[] = {
171 	{"none",	JFFS2_COMPR_MODE_NONE },
172 #ifdef CONFIG_JFFS2_LZO
173 	{"lzo",		JFFS2_COMPR_MODE_FORCELZO },
174 #endif
175 #ifdef CONFIG_JFFS2_ZLIB
176 	{"zlib",	JFFS2_COMPR_MODE_FORCEZLIB },
177 #endif
178 	{}
179 };
180 
181 static const struct fs_parameter_spec jffs2_fs_parameters[] = {
182 	fsparam_enum	("compr",	Opt_override_compr, jffs2_param_compr),
183 	fsparam_u32	("rp_size",	Opt_rp_size),
184 	{}
185 };
186 
187 static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
188 {
189 	struct fs_parse_result result;
190 	struct jffs2_sb_info *c = fc->s_fs_info;
191 	int opt;
192 
193 	opt = fs_parse(fc, jffs2_fs_parameters, param, &result);
194 	if (opt < 0)
195 		return opt;
196 
197 	switch (opt) {
198 	case Opt_override_compr:
199 		c->mount_opts.compr = result.uint_32;
200 		c->mount_opts.override_compr = true;
201 		break;
202 	case Opt_rp_size:
203 		if (result.uint_32 > UINT_MAX / 1024)
204 			return invalf(fc, "jffs2: rp_size unrepresentable");
205 		opt = result.uint_32 * 1024;
206 		if (opt > c->mtd->size)
207 			return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
208 				      c->mtd->size / 1024);
209 		c->mount_opts.rp_size = opt;
210 		break;
211 	default:
212 		return -EINVAL;
213 	}
214 
215 	return 0;
216 }
217 
218 static int jffs2_reconfigure(struct fs_context *fc)
219 {
220 	struct super_block *sb = fc->root->d_sb;
221 
222 	sync_filesystem(sb);
223 	return jffs2_do_remount_fs(sb, fc);
224 }
225 
226 static const struct super_operations jffs2_super_operations =
227 {
228 	.alloc_inode =	jffs2_alloc_inode,
229 	.free_inode =	jffs2_free_inode,
230 	.put_super =	jffs2_put_super,
231 	.statfs =	jffs2_statfs,
232 	.evict_inode =	jffs2_evict_inode,
233 	.dirty_inode =	jffs2_dirty_inode,
234 	.show_options =	jffs2_show_options,
235 	.sync_fs =	jffs2_sync_fs,
236 };
237 
238 /*
239  * fill in the superblock
240  */
241 static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc)
242 {
243 	struct jffs2_sb_info *c = sb->s_fs_info;
244 
245 	jffs2_dbg(1, "jffs2_get_sb_mtd():"
246 		  " New superblock for device %d (\"%s\")\n",
247 		  sb->s_mtd->index, sb->s_mtd->name);
248 
249 	c->mtd = sb->s_mtd;
250 	c->os_priv = sb;
251 
252 	/* Initialize JFFS2 superblock locks, the further initialization will
253 	 * be done later */
254 	mutex_init(&c->alloc_sem);
255 	mutex_init(&c->erase_free_sem);
256 	init_waitqueue_head(&c->erase_wait);
257 	init_waitqueue_head(&c->inocache_wq);
258 	spin_lock_init(&c->erase_completion_lock);
259 	spin_lock_init(&c->inocache_lock);
260 
261 	sb->s_op = &jffs2_super_operations;
262 	sb->s_export_op = &jffs2_export_ops;
263 	sb->s_flags = sb->s_flags | SB_NOATIME;
264 	sb->s_xattr = jffs2_xattr_handlers;
265 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
266 	sb->s_flags |= SB_POSIXACL;
267 #endif
268 	return jffs2_do_fill_super(sb, fc);
269 }
270 
271 static int jffs2_get_tree(struct fs_context *fc)
272 {
273 	return get_tree_mtd(fc, jffs2_fill_super);
274 }
275 
276 static void jffs2_free_fc(struct fs_context *fc)
277 {
278 	kfree(fc->s_fs_info);
279 }
280 
281 static const struct fs_context_operations jffs2_context_ops = {
282 	.free		= jffs2_free_fc,
283 	.parse_param	= jffs2_parse_param,
284 	.get_tree	= jffs2_get_tree,
285 	.reconfigure	= jffs2_reconfigure,
286 };
287 
288 static int jffs2_init_fs_context(struct fs_context *fc)
289 {
290 	struct jffs2_sb_info *ctx;
291 
292 	ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
293 	if (!ctx)
294 		return -ENOMEM;
295 
296 	fc->s_fs_info = ctx;
297 	fc->ops = &jffs2_context_ops;
298 	return 0;
299 }
300 
301 static void jffs2_put_super (struct super_block *sb)
302 {
303 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
304 
305 	jffs2_dbg(2, "%s()\n", __func__);
306 
307 	mutex_lock(&c->alloc_sem);
308 	jffs2_flush_wbuf_pad(c);
309 	mutex_unlock(&c->alloc_sem);
310 
311 	jffs2_sum_exit(c);
312 
313 	jffs2_free_ino_caches(c);
314 	jffs2_free_raw_node_refs(c);
315 	kvfree(c->blocks);
316 	jffs2_flash_cleanup(c);
317 	kfree(c->inocache_list);
318 	jffs2_clear_xattr_subsystem(c);
319 	mtd_sync(c->mtd);
320 	jffs2_dbg(1, "%s(): returning\n", __func__);
321 }
322 
323 static void jffs2_kill_sb(struct super_block *sb)
324 {
325 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
326 	if (c && !sb_rdonly(sb))
327 		jffs2_stop_garbage_collect_thread(c);
328 	kill_mtd_super(sb);
329 	kfree(c);
330 }
331 
332 static struct file_system_type jffs2_fs_type = {
333 	.owner =	THIS_MODULE,
334 	.name =		"jffs2",
335 	.init_fs_context = jffs2_init_fs_context,
336 	.parameters =	jffs2_fs_parameters,
337 	.kill_sb =	jffs2_kill_sb,
338 };
339 MODULE_ALIAS_FS("jffs2");
340 
341 static int __init init_jffs2_fs(void)
342 {
343 	int ret;
344 
345 	/* Paranoia checks for on-medium structures. If we ask GCC
346 	   to pack them with __attribute__((packed)) then it _also_
347 	   assumes that they're not aligned -- so it emits crappy
348 	   code on some architectures. Ideally we want an attribute
349 	   which means just 'no padding', without the alignment
350 	   thing. But GCC doesn't have that -- we have to just
351 	   hope the structs are the right sizes, instead. */
352 	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
353 	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
354 	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
355 	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
356 
357 	pr_info("version 2.2."
358 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
359 	       " (NAND)"
360 #endif
361 #ifdef CONFIG_JFFS2_SUMMARY
362 	       " (SUMMARY) "
363 #endif
364 	       " © 2001-2006 Red Hat, Inc.\n");
365 
366 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
367 					     sizeof(struct jffs2_inode_info),
368 					     0, (SLAB_RECLAIM_ACCOUNT|
369 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
370 					     jffs2_i_init_once);
371 	if (!jffs2_inode_cachep) {
372 		pr_err("error: Failed to initialise inode cache\n");
373 		return -ENOMEM;
374 	}
375 	ret = jffs2_compressors_init();
376 	if (ret) {
377 		pr_err("error: Failed to initialise compressors\n");
378 		goto out;
379 	}
380 	ret = jffs2_create_slab_caches();
381 	if (ret) {
382 		pr_err("error: Failed to initialise slab caches\n");
383 		goto out_compressors;
384 	}
385 	ret = register_filesystem(&jffs2_fs_type);
386 	if (ret) {
387 		pr_err("error: Failed to register filesystem\n");
388 		goto out_slab;
389 	}
390 	return 0;
391 
392  out_slab:
393 	jffs2_destroy_slab_caches();
394  out_compressors:
395 	jffs2_compressors_exit();
396  out:
397 	kmem_cache_destroy(jffs2_inode_cachep);
398 	return ret;
399 }
400 
401 static void __exit exit_jffs2_fs(void)
402 {
403 	unregister_filesystem(&jffs2_fs_type);
404 	jffs2_destroy_slab_caches();
405 	jffs2_compressors_exit();
406 
407 	/*
408 	 * Make sure all delayed rcu free inodes are flushed before we
409 	 * destroy cache.
410 	 */
411 	rcu_barrier();
412 	kmem_cache_destroy(jffs2_inode_cachep);
413 }
414 
415 module_init(init_jffs2_fs);
416 module_exit(exit_jffs2_fs);
417 
418 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
419 MODULE_AUTHOR("Red Hat, Inc.");
420 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
421 		       // the sake of this tag. It's Free Software.
422