bb6ae387469f4d020424bfb13333e24d84e68123
[muen/linux.git] / fs / jffs2 / super.c
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         if (jffs2_is_writebuffered(c))
105                 cancel_delayed_work_sync(&c->wbuf_dwork);
106 #endif
107
108         mutex_lock(&c->alloc_sem);
109         jffs2_flush_wbuf_pad(c);
110         mutex_unlock(&c->alloc_sem);
111         return 0;
112 }
113
114 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
115                                          uint32_t generation)
116 {
117         /* We don't care about i_generation. We'll destroy the flash
118            before we start re-using inode numbers anyway. And even
119            if that wasn't true, we'd have other problems...*/
120         return jffs2_iget(sb, ino);
121 }
122
123 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
124                                          int fh_len, int fh_type)
125 {
126         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
127                                     jffs2_nfs_get_inode);
128 }
129
130 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
131                                          int fh_len, int fh_type)
132 {
133         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
134                                     jffs2_nfs_get_inode);
135 }
136
137 static struct dentry *jffs2_get_parent(struct dentry *child)
138 {
139         struct jffs2_inode_info *f;
140         uint32_t pino;
141
142         BUG_ON(!d_is_dir(child));
143
144         f = JFFS2_INODE_INFO(d_inode(child));
145
146         pino = f->inocache->pino_nlink;
147
148         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
149                     f->inocache->ino, pino);
150
151         return d_obtain_alias(jffs2_iget(child->d_sb, pino));
152 }
153
154 static const struct export_operations jffs2_export_ops = {
155         .get_parent = jffs2_get_parent,
156         .fh_to_dentry = jffs2_fh_to_dentry,
157         .fh_to_parent = jffs2_fh_to_parent,
158 };
159
160 /*
161  * JFFS2 mount options.
162  *
163  * Opt_override_compr: override default compressor
164  * Opt_rp_size: size of reserved pool in KiB
165  * Opt_err: just end of array marker
166  */
167 enum {
168         Opt_override_compr,
169         Opt_rp_size,
170         Opt_err,
171 };
172
173 static const match_table_t tokens = {
174         {Opt_override_compr, "compr=%s"},
175         {Opt_rp_size, "rp_size=%u"},
176         {Opt_err, NULL},
177 };
178
179 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
180 {
181         substring_t args[MAX_OPT_ARGS];
182         char *p, *name;
183         unsigned int opt;
184
185         if (!data)
186                 return 0;
187
188         while ((p = strsep(&data, ","))) {
189                 int token;
190
191                 if (!*p)
192                         continue;
193
194                 token = match_token(p, tokens, args);
195                 switch (token) {
196                 case Opt_override_compr:
197                         name = match_strdup(&args[0]);
198
199                         if (!name)
200                                 return -ENOMEM;
201                         if (!strcmp(name, "none"))
202                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
203 #ifdef CONFIG_JFFS2_LZO
204                         else if (!strcmp(name, "lzo"))
205                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
206 #endif
207 #ifdef CONFIG_JFFS2_ZLIB
208                         else if (!strcmp(name, "zlib"))
209                                 c->mount_opts.compr =
210                                                 JFFS2_COMPR_MODE_FORCEZLIB;
211 #endif
212                         else {
213                                 pr_err("Error: unknown compressor \"%s\"\n",
214                                        name);
215                                 kfree(name);
216                                 return -EINVAL;
217                         }
218                         kfree(name);
219                         c->mount_opts.override_compr = true;
220                         break;
221                 case Opt_rp_size:
222                         if (match_int(&args[0], &opt))
223                                 return -EINVAL;
224                         opt *= 1024;
225                         if (opt > c->mtd->size) {
226                                 pr_warn("Too large reserve pool specified, max "
227                                         "is %llu KB\n", c->mtd->size / 1024);
228                                 return -EINVAL;
229                         }
230                         c->mount_opts.rp_size = opt;
231                         break;
232                 default:
233                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
234                                p);
235                         return -EINVAL;
236                 }
237         }
238
239         return 0;
240 }
241
242 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
243 {
244         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
245         int err;
246
247         sync_filesystem(sb);
248         err = jffs2_parse_options(c, data);
249         if (err)
250                 return -EINVAL;
251
252         return jffs2_do_remount_fs(sb, flags, data);
253 }
254
255 static const struct super_operations jffs2_super_operations =
256 {
257         .alloc_inode =  jffs2_alloc_inode,
258         .destroy_inode =jffs2_destroy_inode,
259         .put_super =    jffs2_put_super,
260         .statfs =       jffs2_statfs,
261         .remount_fs =   jffs2_remount_fs,
262         .evict_inode =  jffs2_evict_inode,
263         .dirty_inode =  jffs2_dirty_inode,
264         .show_options = jffs2_show_options,
265         .sync_fs =      jffs2_sync_fs,
266 };
267
268 /*
269  * fill in the superblock
270  */
271 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
272 {
273         struct jffs2_sb_info *c;
274         int ret;
275
276         jffs2_dbg(1, "jffs2_get_sb_mtd():"
277                   " New superblock for device %d (\"%s\")\n",
278                   sb->s_mtd->index, sb->s_mtd->name);
279
280         c = kzalloc(sizeof(*c), GFP_KERNEL);
281         if (!c)
282                 return -ENOMEM;
283
284         c->mtd = sb->s_mtd;
285         c->os_priv = sb;
286         sb->s_fs_info = c;
287
288         ret = jffs2_parse_options(c, data);
289         if (ret)
290                 return -EINVAL;
291
292         /* Initialize JFFS2 superblock locks, the further initialization will
293          * be done later */
294         mutex_init(&c->alloc_sem);
295         mutex_init(&c->erase_free_sem);
296         init_waitqueue_head(&c->erase_wait);
297         init_waitqueue_head(&c->inocache_wq);
298         spin_lock_init(&c->erase_completion_lock);
299         spin_lock_init(&c->inocache_lock);
300
301         sb->s_op = &jffs2_super_operations;
302         sb->s_export_op = &jffs2_export_ops;
303         sb->s_flags = sb->s_flags | SB_NOATIME;
304         sb->s_xattr = jffs2_xattr_handlers;
305 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
306         sb->s_flags |= SB_POSIXACL;
307 #endif
308         ret = jffs2_do_fill_super(sb, data, silent);
309         return ret;
310 }
311
312 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
313                         int flags, const char *dev_name,
314                         void *data)
315 {
316         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
317 }
318
319 static void jffs2_put_super (struct super_block *sb)
320 {
321         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
322
323         jffs2_dbg(2, "%s()\n", __func__);
324
325         mutex_lock(&c->alloc_sem);
326         jffs2_flush_wbuf_pad(c);
327         mutex_unlock(&c->alloc_sem);
328
329         jffs2_sum_exit(c);
330
331         jffs2_free_ino_caches(c);
332         jffs2_free_raw_node_refs(c);
333         kvfree(c->blocks);
334         jffs2_flash_cleanup(c);
335         kfree(c->inocache_list);
336         jffs2_clear_xattr_subsystem(c);
337         mtd_sync(c->mtd);
338         jffs2_dbg(1, "%s(): returning\n", __func__);
339 }
340
341 static void jffs2_kill_sb(struct super_block *sb)
342 {
343         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
344         if (c && !sb_rdonly(sb))
345                 jffs2_stop_garbage_collect_thread(c);
346         kill_mtd_super(sb);
347         kfree(c);
348 }
349
350 static struct file_system_type jffs2_fs_type = {
351         .owner =        THIS_MODULE,
352         .name =         "jffs2",
353         .mount =        jffs2_mount,
354         .kill_sb =      jffs2_kill_sb,
355 };
356 MODULE_ALIAS_FS("jffs2");
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         pr_info("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|SLAB_ACCOUNT),
387                                              jffs2_i_init_once);
388         if (!jffs2_inode_cachep) {
389                 pr_err("error: Failed to initialise inode cache\n");
390                 return -ENOMEM;
391         }
392         ret = jffs2_compressors_init();
393         if (ret) {
394                 pr_err("error: Failed to initialise compressors\n");
395                 goto out;
396         }
397         ret = jffs2_create_slab_caches();
398         if (ret) {
399                 pr_err("error: Failed to initialise slab caches\n");
400                 goto out_compressors;
401         }
402         ret = register_filesystem(&jffs2_fs_type);
403         if (ret) {
404                 pr_err("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
424         /*
425          * Make sure all delayed rcu free inodes are flushed before we
426          * destroy cache.
427          */
428         rcu_barrier();
429         kmem_cache_destroy(jffs2_inode_cachep);
430 }
431
432 module_init(init_jffs2_fs);
433 module_exit(exit_jffs2_fs);
434
435 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
436 MODULE_AUTHOR("Red Hat, Inc.");
437 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
438                        // the sake of this tag. It's Free Software.