xref: /openbmc/linux/fs/jffs2/super.c (revision d0bbbf31)
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 = alloc_inode_sb(sb, 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 	f->target = NULL;
62 	inode_init_once(&f->vfs_inode);
63 }
64 
jffs2_compr_name(unsigned int compr)65 static const char *jffs2_compr_name(unsigned int compr)
66 {
67 	switch (compr) {
68 	case JFFS2_COMPR_MODE_NONE:
69 		return "none";
70 #ifdef CONFIG_JFFS2_LZO
71 	case JFFS2_COMPR_MODE_FORCELZO:
72 		return "lzo";
73 #endif
74 #ifdef CONFIG_JFFS2_ZLIB
75 	case JFFS2_COMPR_MODE_FORCEZLIB:
76 		return "zlib";
77 #endif
78 	default:
79 		/* should never happen; programmer error */
80 		WARN_ON(1);
81 		return "";
82 	}
83 }
84 
jffs2_show_options(struct seq_file * s,struct dentry * root)85 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
86 {
87 	struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
88 	struct jffs2_mount_opts *opts = &c->mount_opts;
89 
90 	if (opts->override_compr)
91 		seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
92 	if (opts->set_rp_size)
93 		seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
94 
95 	return 0;
96 }
97 
jffs2_sync_fs(struct super_block * sb,int wait)98 static int jffs2_sync_fs(struct super_block *sb, int wait)
99 {
100 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
101 
102 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
103 	if (jffs2_is_writebuffered(c))
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 
jffs2_nfs_get_inode(struct super_block * sb,uint64_t ino,uint32_t generation)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 
jffs2_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)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 
jffs2_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)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 
jffs2_get_parent(struct dentry * child)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_source: The source device
163  * Opt_override_compr: override default compressor
164  * Opt_rp_size: size of reserved pool in KiB
165  */
166 enum {
167 	Opt_override_compr,
168 	Opt_rp_size,
169 };
170 
171 static const struct constant_table jffs2_param_compr[] = {
172 	{"none",	JFFS2_COMPR_MODE_NONE },
173 #ifdef CONFIG_JFFS2_LZO
174 	{"lzo",		JFFS2_COMPR_MODE_FORCELZO },
175 #endif
176 #ifdef CONFIG_JFFS2_ZLIB
177 	{"zlib",	JFFS2_COMPR_MODE_FORCEZLIB },
178 #endif
179 	{}
180 };
181 
182 static const struct fs_parameter_spec jffs2_fs_parameters[] = {
183 	fsparam_enum	("compr",	Opt_override_compr, jffs2_param_compr),
184 	fsparam_u32	("rp_size",	Opt_rp_size),
185 	{}
186 };
187 
jffs2_parse_param(struct fs_context * fc,struct fs_parameter * param)188 static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
189 {
190 	struct fs_parse_result result;
191 	struct jffs2_sb_info *c = fc->s_fs_info;
192 	int opt;
193 
194 	opt = fs_parse(fc, jffs2_fs_parameters, param, &result);
195 	if (opt < 0)
196 		return opt;
197 
198 	switch (opt) {
199 	case Opt_override_compr:
200 		c->mount_opts.compr = result.uint_32;
201 		c->mount_opts.override_compr = true;
202 		break;
203 	case Opt_rp_size:
204 		if (result.uint_32 > UINT_MAX / 1024)
205 			return invalf(fc, "jffs2: rp_size unrepresentable");
206 		c->mount_opts.rp_size = result.uint_32 * 1024;
207 		c->mount_opts.set_rp_size = true;
208 		break;
209 	default:
210 		return -EINVAL;
211 	}
212 
213 	return 0;
214 }
215 
jffs2_update_mount_opts(struct fs_context * fc)216 static inline void jffs2_update_mount_opts(struct fs_context *fc)
217 {
218 	struct jffs2_sb_info *new_c = fc->s_fs_info;
219 	struct jffs2_sb_info *c = JFFS2_SB_INFO(fc->root->d_sb);
220 
221 	mutex_lock(&c->alloc_sem);
222 	if (new_c->mount_opts.override_compr) {
223 		c->mount_opts.override_compr = new_c->mount_opts.override_compr;
224 		c->mount_opts.compr = new_c->mount_opts.compr;
225 	}
226 	if (new_c->mount_opts.set_rp_size) {
227 		c->mount_opts.set_rp_size = new_c->mount_opts.set_rp_size;
228 		c->mount_opts.rp_size = new_c->mount_opts.rp_size;
229 	}
230 	mutex_unlock(&c->alloc_sem);
231 }
232 
jffs2_reconfigure(struct fs_context * fc)233 static int jffs2_reconfigure(struct fs_context *fc)
234 {
235 	struct super_block *sb = fc->root->d_sb;
236 
237 	sync_filesystem(sb);
238 	jffs2_update_mount_opts(fc);
239 
240 	return jffs2_do_remount_fs(sb, fc);
241 }
242 
243 static const struct super_operations jffs2_super_operations =
244 {
245 	.alloc_inode =	jffs2_alloc_inode,
246 	.free_inode =	jffs2_free_inode,
247 	.put_super =	jffs2_put_super,
248 	.statfs =	jffs2_statfs,
249 	.evict_inode =	jffs2_evict_inode,
250 	.dirty_inode =	jffs2_dirty_inode,
251 	.show_options =	jffs2_show_options,
252 	.sync_fs =	jffs2_sync_fs,
253 };
254 
255 /*
256  * fill in the superblock
257  */
jffs2_fill_super(struct super_block * sb,struct fs_context * fc)258 static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc)
259 {
260 	struct jffs2_sb_info *c = sb->s_fs_info;
261 
262 	jffs2_dbg(1, "jffs2_get_sb_mtd():"
263 		  " New superblock for device %d (\"%s\")\n",
264 		  sb->s_mtd->index, sb->s_mtd->name);
265 
266 	c->mtd = sb->s_mtd;
267 	c->os_priv = sb;
268 
269 	if (c->mount_opts.rp_size > c->mtd->size)
270 		return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
271 			      c->mtd->size / 1024);
272 
273 	/* Initialize JFFS2 superblock locks, the further initialization will
274 	 * be done later */
275 	mutex_init(&c->alloc_sem);
276 	mutex_init(&c->erase_free_sem);
277 	init_waitqueue_head(&c->erase_wait);
278 	init_waitqueue_head(&c->inocache_wq);
279 	spin_lock_init(&c->erase_completion_lock);
280 	spin_lock_init(&c->inocache_lock);
281 
282 	sb->s_op = &jffs2_super_operations;
283 	sb->s_export_op = &jffs2_export_ops;
284 	sb->s_flags = sb->s_flags | SB_NOATIME;
285 	sb->s_xattr = jffs2_xattr_handlers;
286 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
287 	sb->s_flags |= SB_POSIXACL;
288 #endif
289 	return jffs2_do_fill_super(sb, fc);
290 }
291 
jffs2_get_tree(struct fs_context * fc)292 static int jffs2_get_tree(struct fs_context *fc)
293 {
294 	return get_tree_mtd(fc, jffs2_fill_super);
295 }
296 
jffs2_free_fc(struct fs_context * fc)297 static void jffs2_free_fc(struct fs_context *fc)
298 {
299 	kfree(fc->s_fs_info);
300 }
301 
302 static const struct fs_context_operations jffs2_context_ops = {
303 	.free		= jffs2_free_fc,
304 	.parse_param	= jffs2_parse_param,
305 	.get_tree	= jffs2_get_tree,
306 	.reconfigure	= jffs2_reconfigure,
307 };
308 
jffs2_init_fs_context(struct fs_context * fc)309 static int jffs2_init_fs_context(struct fs_context *fc)
310 {
311 	struct jffs2_sb_info *ctx;
312 
313 	ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
314 	if (!ctx)
315 		return -ENOMEM;
316 
317 	fc->s_fs_info = ctx;
318 	fc->ops = &jffs2_context_ops;
319 	return 0;
320 }
321 
jffs2_put_super(struct super_block * sb)322 static void jffs2_put_super (struct super_block *sb)
323 {
324 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
325 
326 	jffs2_dbg(2, "%s()\n", __func__);
327 
328 	mutex_lock(&c->alloc_sem);
329 	jffs2_flush_wbuf_pad(c);
330 	mutex_unlock(&c->alloc_sem);
331 
332 	jffs2_sum_exit(c);
333 
334 	jffs2_free_ino_caches(c);
335 	jffs2_free_raw_node_refs(c);
336 	kvfree(c->blocks);
337 	jffs2_flash_cleanup(c);
338 	kfree(c->inocache_list);
339 	jffs2_clear_xattr_subsystem(c);
340 	mtd_sync(c->mtd);
341 	jffs2_dbg(1, "%s(): returning\n", __func__);
342 }
343 
jffs2_kill_sb(struct super_block * sb)344 static void jffs2_kill_sb(struct super_block *sb)
345 {
346 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
347 	if (c && !sb_rdonly(sb))
348 		jffs2_stop_garbage_collect_thread(c);
349 	kill_mtd_super(sb);
350 	kfree(c);
351 }
352 
353 static struct file_system_type jffs2_fs_type = {
354 	.owner =	THIS_MODULE,
355 	.name =		"jffs2",
356 	.init_fs_context = jffs2_init_fs_context,
357 	.parameters =	jffs2_fs_parameters,
358 	.kill_sb =	jffs2_kill_sb,
359 };
360 MODULE_ALIAS_FS("jffs2");
361 
init_jffs2_fs(void)362 static int __init init_jffs2_fs(void)
363 {
364 	int ret;
365 
366 	/* Paranoia checks for on-medium structures. If we ask GCC
367 	   to pack them with __attribute__((packed)) then it _also_
368 	   assumes that they're not aligned -- so it emits crappy
369 	   code on some architectures. Ideally we want an attribute
370 	   which means just 'no padding', without the alignment
371 	   thing. But GCC doesn't have that -- we have to just
372 	   hope the structs are the right sizes, instead. */
373 	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
374 	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
375 	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
376 	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
377 
378 	pr_info("version 2.2."
379 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
380 	       " (NAND)"
381 #endif
382 #ifdef CONFIG_JFFS2_SUMMARY
383 	       " (SUMMARY) "
384 #endif
385 	       " © 2001-2006 Red Hat, Inc.\n");
386 
387 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
388 					     sizeof(struct jffs2_inode_info),
389 					     0, (SLAB_RECLAIM_ACCOUNT|
390 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
391 					     jffs2_i_init_once);
392 	if (!jffs2_inode_cachep) {
393 		pr_err("error: Failed to initialise inode cache\n");
394 		return -ENOMEM;
395 	}
396 	ret = jffs2_compressors_init();
397 	if (ret) {
398 		pr_err("error: Failed to initialise compressors\n");
399 		goto out;
400 	}
401 	ret = jffs2_create_slab_caches();
402 	if (ret) {
403 		pr_err("error: Failed to initialise slab caches\n");
404 		goto out_compressors;
405 	}
406 	ret = register_filesystem(&jffs2_fs_type);
407 	if (ret) {
408 		pr_err("error: Failed to register filesystem\n");
409 		goto out_slab;
410 	}
411 	return 0;
412 
413  out_slab:
414 	jffs2_destroy_slab_caches();
415  out_compressors:
416 	jffs2_compressors_exit();
417  out:
418 	kmem_cache_destroy(jffs2_inode_cachep);
419 	return ret;
420 }
421 
exit_jffs2_fs(void)422 static void __exit exit_jffs2_fs(void)
423 {
424 	unregister_filesystem(&jffs2_fs_type);
425 	jffs2_destroy_slab_caches();
426 	jffs2_compressors_exit();
427 
428 	/*
429 	 * Make sure all delayed rcu free inodes are flushed before we
430 	 * destroy cache.
431 	 */
432 	rcu_barrier();
433 	kmem_cache_destroy(jffs2_inode_cachep);
434 }
435 
436 module_init(init_jffs2_fs);
437 module_exit(exit_jffs2_fs);
438 
439 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
440 MODULE_AUTHOR("Red Hat, Inc.");
441 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
442 		       // the sake of this tag. It's Free Software.
443