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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 
jffs2_alloc_inode(struct super_block * sb)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 
jffs2_free_inode(struct inode * inode)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 
jffs2_i_init_once(void * foo)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 
jffs2_compr_name(unsigned int compr)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 
jffs2_show_options(struct seq_file * s,struct dentry * root)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->set_rp_size)
92 		seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
93 
94 	return 0;
95 }
96 
jffs2_sync_fs(struct super_block * sb,int wait)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 
jffs2_nfs_get_inode(struct super_block * sb,uint64_t ino,uint32_t generation)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 
jffs2_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)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 
jffs2_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)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 
jffs2_get_parent(struct dentry * child)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 fs_parameter_spec jffs2_param_specs[] = {
171 	fsparam_enum	("compr",	Opt_override_compr),
172 	fsparam_u32	("rp_size",	Opt_rp_size),
173 	{}
174 };
175 
176 static const struct fs_parameter_enum jffs2_param_enums[] = {
177 	{ Opt_override_compr,	"none",	JFFS2_COMPR_MODE_NONE },
178 #ifdef CONFIG_JFFS2_LZO
179 	{ Opt_override_compr,	"lzo",	JFFS2_COMPR_MODE_FORCELZO },
180 #endif
181 #ifdef CONFIG_JFFS2_ZLIB
182 	{ Opt_override_compr,	"zlib",	JFFS2_COMPR_MODE_FORCEZLIB },
183 #endif
184 	{}
185 };
186 
187 const struct fs_parameter_description jffs2_fs_parameters = {
188 	.name		= "jffs2",
189 	.specs		= jffs2_param_specs,
190 	.enums		= jffs2_param_enums,
191 };
192 
jffs2_parse_param(struct fs_context * fc,struct fs_parameter * param)193 static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
194 {
195 	struct fs_parse_result result;
196 	struct jffs2_sb_info *c = fc->s_fs_info;
197 	int opt;
198 
199 	opt = fs_parse(fc, &jffs2_fs_parameters, param, &result);
200 	if (opt < 0)
201 		return opt;
202 
203 	switch (opt) {
204 	case Opt_override_compr:
205 		c->mount_opts.compr = result.uint_32;
206 		c->mount_opts.override_compr = true;
207 		break;
208 	case Opt_rp_size:
209 		if (result.uint_32 > UINT_MAX / 1024)
210 			return invalf(fc, "jffs2: rp_size unrepresentable");
211 		c->mount_opts.rp_size = result.uint_32 * 1024;
212 		c->mount_opts.set_rp_size = true;
213 		break;
214 	default:
215 		return -EINVAL;
216 	}
217 
218 	return 0;
219 }
220 
jffs2_update_mount_opts(struct fs_context * fc)221 static inline void jffs2_update_mount_opts(struct fs_context *fc)
222 {
223 	struct jffs2_sb_info *new_c = fc->s_fs_info;
224 	struct jffs2_sb_info *c = JFFS2_SB_INFO(fc->root->d_sb);
225 
226 	mutex_lock(&c->alloc_sem);
227 	if (new_c->mount_opts.override_compr) {
228 		c->mount_opts.override_compr = new_c->mount_opts.override_compr;
229 		c->mount_opts.compr = new_c->mount_opts.compr;
230 	}
231 	if (new_c->mount_opts.set_rp_size) {
232 		c->mount_opts.set_rp_size = new_c->mount_opts.set_rp_size;
233 		c->mount_opts.rp_size = new_c->mount_opts.rp_size;
234 	}
235 	mutex_unlock(&c->alloc_sem);
236 }
237 
jffs2_reconfigure(struct fs_context * fc)238 static int jffs2_reconfigure(struct fs_context *fc)
239 {
240 	struct super_block *sb = fc->root->d_sb;
241 
242 	sync_filesystem(sb);
243 	jffs2_update_mount_opts(fc);
244 
245 	return jffs2_do_remount_fs(sb, fc);
246 }
247 
248 static const struct super_operations jffs2_super_operations =
249 {
250 	.alloc_inode =	jffs2_alloc_inode,
251 	.free_inode =	jffs2_free_inode,
252 	.put_super =	jffs2_put_super,
253 	.statfs =	jffs2_statfs,
254 	.evict_inode =	jffs2_evict_inode,
255 	.dirty_inode =	jffs2_dirty_inode,
256 	.show_options =	jffs2_show_options,
257 	.sync_fs =	jffs2_sync_fs,
258 };
259 
260 /*
261  * fill in the superblock
262  */
jffs2_fill_super(struct super_block * sb,struct fs_context * fc)263 static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc)
264 {
265 	struct jffs2_sb_info *c = sb->s_fs_info;
266 
267 	jffs2_dbg(1, "jffs2_get_sb_mtd():"
268 		  " New superblock for device %d (\"%s\")\n",
269 		  sb->s_mtd->index, sb->s_mtd->name);
270 
271 	c->mtd = sb->s_mtd;
272 	c->os_priv = sb;
273 
274 	if (c->mount_opts.rp_size > c->mtd->size)
275 		return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
276 			      c->mtd->size / 1024);
277 
278 	/* Initialize JFFS2 superblock locks, the further initialization will
279 	 * be done later */
280 	mutex_init(&c->alloc_sem);
281 	mutex_init(&c->erase_free_sem);
282 	init_waitqueue_head(&c->erase_wait);
283 	init_waitqueue_head(&c->inocache_wq);
284 	spin_lock_init(&c->erase_completion_lock);
285 	spin_lock_init(&c->inocache_lock);
286 
287 	sb->s_op = &jffs2_super_operations;
288 	sb->s_export_op = &jffs2_export_ops;
289 	sb->s_flags = sb->s_flags | SB_NOATIME;
290 	sb->s_xattr = jffs2_xattr_handlers;
291 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
292 	sb->s_flags |= SB_POSIXACL;
293 #endif
294 	return jffs2_do_fill_super(sb, fc);
295 }
296 
jffs2_get_tree(struct fs_context * fc)297 static int jffs2_get_tree(struct fs_context *fc)
298 {
299 	return get_tree_mtd(fc, jffs2_fill_super);
300 }
301 
jffs2_free_fc(struct fs_context * fc)302 static void jffs2_free_fc(struct fs_context *fc)
303 {
304 	kfree(fc->s_fs_info);
305 }
306 
307 static const struct fs_context_operations jffs2_context_ops = {
308 	.free		= jffs2_free_fc,
309 	.parse_param	= jffs2_parse_param,
310 	.get_tree	= jffs2_get_tree,
311 	.reconfigure	= jffs2_reconfigure,
312 };
313 
jffs2_init_fs_context(struct fs_context * fc)314 static int jffs2_init_fs_context(struct fs_context *fc)
315 {
316 	struct jffs2_sb_info *ctx;
317 
318 	ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
319 	if (!ctx)
320 		return -ENOMEM;
321 
322 	fc->s_fs_info = ctx;
323 	fc->ops = &jffs2_context_ops;
324 	return 0;
325 }
326 
jffs2_put_super(struct super_block * sb)327 static void jffs2_put_super (struct super_block *sb)
328 {
329 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
330 
331 	jffs2_dbg(2, "%s()\n", __func__);
332 
333 	mutex_lock(&c->alloc_sem);
334 	jffs2_flush_wbuf_pad(c);
335 	mutex_unlock(&c->alloc_sem);
336 
337 	jffs2_sum_exit(c);
338 
339 	jffs2_free_ino_caches(c);
340 	jffs2_free_raw_node_refs(c);
341 	kvfree(c->blocks);
342 	jffs2_flash_cleanup(c);
343 	kfree(c->inocache_list);
344 	jffs2_clear_xattr_subsystem(c);
345 	mtd_sync(c->mtd);
346 	jffs2_dbg(1, "%s(): returning\n", __func__);
347 }
348 
jffs2_kill_sb(struct super_block * sb)349 static void jffs2_kill_sb(struct super_block *sb)
350 {
351 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
352 	if (c && !sb_rdonly(sb))
353 		jffs2_stop_garbage_collect_thread(c);
354 	kill_mtd_super(sb);
355 	kfree(c);
356 }
357 
358 static struct file_system_type jffs2_fs_type = {
359 	.owner =	THIS_MODULE,
360 	.name =		"jffs2",
361 	.init_fs_context = jffs2_init_fs_context,
362 	.parameters =	&jffs2_fs_parameters,
363 	.kill_sb =	jffs2_kill_sb,
364 };
365 MODULE_ALIAS_FS("jffs2");
366 
init_jffs2_fs(void)367 static int __init init_jffs2_fs(void)
368 {
369 	int ret;
370 
371 	/* Paranoia checks for on-medium structures. If we ask GCC
372 	   to pack them with __attribute__((packed)) then it _also_
373 	   assumes that they're not aligned -- so it emits crappy
374 	   code on some architectures. Ideally we want an attribute
375 	   which means just 'no padding', without the alignment
376 	   thing. But GCC doesn't have that -- we have to just
377 	   hope the structs are the right sizes, instead. */
378 	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
379 	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
380 	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
381 	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
382 
383 	pr_info("version 2.2."
384 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
385 	       " (NAND)"
386 #endif
387 #ifdef CONFIG_JFFS2_SUMMARY
388 	       " (SUMMARY) "
389 #endif
390 	       " © 2001-2006 Red Hat, Inc.\n");
391 
392 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
393 					     sizeof(struct jffs2_inode_info),
394 					     0, (SLAB_RECLAIM_ACCOUNT|
395 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
396 					     jffs2_i_init_once);
397 	if (!jffs2_inode_cachep) {
398 		pr_err("error: Failed to initialise inode cache\n");
399 		return -ENOMEM;
400 	}
401 	ret = jffs2_compressors_init();
402 	if (ret) {
403 		pr_err("error: Failed to initialise compressors\n");
404 		goto out;
405 	}
406 	ret = jffs2_create_slab_caches();
407 	if (ret) {
408 		pr_err("error: Failed to initialise slab caches\n");
409 		goto out_compressors;
410 	}
411 	ret = register_filesystem(&jffs2_fs_type);
412 	if (ret) {
413 		pr_err("error: Failed to register filesystem\n");
414 		goto out_slab;
415 	}
416 	return 0;
417 
418  out_slab:
419 	jffs2_destroy_slab_caches();
420  out_compressors:
421 	jffs2_compressors_exit();
422  out:
423 	kmem_cache_destroy(jffs2_inode_cachep);
424 	return ret;
425 }
426 
exit_jffs2_fs(void)427 static void __exit exit_jffs2_fs(void)
428 {
429 	unregister_filesystem(&jffs2_fs_type);
430 	jffs2_destroy_slab_caches();
431 	jffs2_compressors_exit();
432 
433 	/*
434 	 * Make sure all delayed rcu free inodes are flushed before we
435 	 * destroy cache.
436 	 */
437 	rcu_barrier();
438 	kmem_cache_destroy(jffs2_inode_cachep);
439 }
440 
441 module_init(init_jffs2_fs);
442 module_exit(exit_jffs2_fs);
443 
444 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
445 MODULE_AUTHOR("Red Hat, Inc.");
446 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
447 		       // the sake of this tag. It's Free Software.
448