JFFS2: Add parameter to reserve disk space for root
[linux-3.10.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 void jffs2_write_super(struct super_block *sb)
67 {
68         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
69
70         lock_super(sb);
71         sb->s_dirt = 0;
72
73         if (!(sb->s_flags & MS_RDONLY)) {
74                 jffs2_dbg(1, "%s()\n", __func__);
75                 jffs2_flush_wbuf_gc(c, 0);
76         }
77
78         unlock_super(sb);
79 }
80
81 static const char *jffs2_compr_name(unsigned int compr)
82 {
83         switch (compr) {
84         case JFFS2_COMPR_MODE_NONE:
85                 return "none";
86 #ifdef CONFIG_JFFS2_LZO
87         case JFFS2_COMPR_MODE_FORCELZO:
88                 return "lzo";
89 #endif
90 #ifdef CONFIG_JFFS2_ZLIB
91         case JFFS2_COMPR_MODE_FORCEZLIB:
92                 return "zlib";
93 #endif
94         default:
95                 /* should never happen; programmer error */
96                 WARN_ON(1);
97                 return "";
98         }
99 }
100
101 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
102 {
103         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
104         struct jffs2_mount_opts *opts = &c->mount_opts;
105
106         if (opts->override_compr)
107                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
108         if (opts->rp_size)
109                 seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
110
111         return 0;
112 }
113
114 static int jffs2_sync_fs(struct super_block *sb, int wait)
115 {
116         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
117
118         jffs2_write_super(sb);
119
120         mutex_lock(&c->alloc_sem);
121         jffs2_flush_wbuf_pad(c);
122         mutex_unlock(&c->alloc_sem);
123         return 0;
124 }
125
126 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
127                                          uint32_t generation)
128 {
129         /* We don't care about i_generation. We'll destroy the flash
130            before we start re-using inode numbers anyway. And even
131            if that wasn't true, we'd have other problems...*/
132         return jffs2_iget(sb, ino);
133 }
134
135 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
136                                          int fh_len, int fh_type)
137 {
138         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
139                                     jffs2_nfs_get_inode);
140 }
141
142 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
143                                          int fh_len, int fh_type)
144 {
145         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
146                                     jffs2_nfs_get_inode);
147 }
148
149 static struct dentry *jffs2_get_parent(struct dentry *child)
150 {
151         struct jffs2_inode_info *f;
152         uint32_t pino;
153
154         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
155
156         f = JFFS2_INODE_INFO(child->d_inode);
157
158         pino = f->inocache->pino_nlink;
159
160         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
161                     f->inocache->ino, pino);
162
163         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
164 }
165
166 static const struct export_operations jffs2_export_ops = {
167         .get_parent = jffs2_get_parent,
168         .fh_to_dentry = jffs2_fh_to_dentry,
169         .fh_to_parent = jffs2_fh_to_parent,
170 };
171
172 /*
173  * JFFS2 mount options.
174  *
175  * Opt_override_compr: override default compressor
176  * Opt_rp_size: size of reserved pool in KiB
177  * Opt_err: just end of array marker
178  */
179 enum {
180         Opt_override_compr,
181         Opt_rp_size,
182         Opt_err,
183 };
184
185 static const match_table_t tokens = {
186         {Opt_override_compr, "compr=%s"},
187         {Opt_rp_size, "rp_size=%u"},
188         {Opt_err, NULL},
189 };
190
191 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
192 {
193         substring_t args[MAX_OPT_ARGS];
194         char *p, *name;
195         unsigned int opt;
196
197         if (!data)
198                 return 0;
199
200         while ((p = strsep(&data, ","))) {
201                 int token;
202
203                 if (!*p)
204                         continue;
205
206                 token = match_token(p, tokens, args);
207                 switch (token) {
208                 case Opt_override_compr:
209                         name = match_strdup(&args[0]);
210
211                         if (!name)
212                                 return -ENOMEM;
213                         if (!strcmp(name, "none"))
214                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
215 #ifdef CONFIG_JFFS2_LZO
216                         else if (!strcmp(name, "lzo"))
217                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
218 #endif
219 #ifdef CONFIG_JFFS2_ZLIB
220                         else if (!strcmp(name, "zlib"))
221                                 c->mount_opts.compr =
222                                                 JFFS2_COMPR_MODE_FORCEZLIB;
223 #endif
224                         else {
225                                 pr_err("Error: unknown compressor \"%s\"\n",
226                                        name);
227                                 kfree(name);
228                                 return -EINVAL;
229                         }
230                         kfree(name);
231                         c->mount_opts.override_compr = true;
232                         break;
233                 case Opt_rp_size:
234                         if (match_int(&args[0], &opt))
235                                 return -EINVAL;
236                         opt *= 1024;
237                         if (opt > c->mtd->size) {
238                                 pr_warn("Too large reserve pool specified, max "
239                                         "is %llu KB\n", c->mtd->size / 1024);
240                                 return -EINVAL;
241                         }
242                         c->mount_opts.rp_size = opt;
243                         break;
244                 default:
245                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
246                                p);
247                         return -EINVAL;
248                 }
249         }
250
251         return 0;
252 }
253
254 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
255 {
256         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
257         int err;
258
259         err = jffs2_parse_options(c, data);
260         if (err)
261                 return -EINVAL;
262
263         return jffs2_do_remount_fs(sb, flags, data);
264 }
265
266 static const struct super_operations jffs2_super_operations =
267 {
268         .alloc_inode =  jffs2_alloc_inode,
269         .destroy_inode =jffs2_destroy_inode,
270         .put_super =    jffs2_put_super,
271         .write_super =  jffs2_write_super,
272         .statfs =       jffs2_statfs,
273         .remount_fs =   jffs2_remount_fs,
274         .evict_inode =  jffs2_evict_inode,
275         .dirty_inode =  jffs2_dirty_inode,
276         .show_options = jffs2_show_options,
277         .sync_fs =      jffs2_sync_fs,
278 };
279
280 /*
281  * fill in the superblock
282  */
283 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
284 {
285         struct jffs2_sb_info *c;
286         int ret;
287
288         jffs2_dbg(1, "jffs2_get_sb_mtd():"
289                   " New superblock for device %d (\"%s\")\n",
290                   sb->s_mtd->index, sb->s_mtd->name);
291
292         c = kzalloc(sizeof(*c), GFP_KERNEL);
293         if (!c)
294                 return -ENOMEM;
295
296         c->mtd = sb->s_mtd;
297         c->os_priv = sb;
298         sb->s_fs_info = c;
299
300         ret = jffs2_parse_options(c, data);
301         if (ret) {
302                 kfree(c);
303                 return -EINVAL;
304         }
305
306         /* Initialize JFFS2 superblock locks, the further initialization will
307          * be done later */
308         mutex_init(&c->alloc_sem);
309         mutex_init(&c->erase_free_sem);
310         init_waitqueue_head(&c->erase_wait);
311         init_waitqueue_head(&c->inocache_wq);
312         spin_lock_init(&c->erase_completion_lock);
313         spin_lock_init(&c->inocache_lock);
314
315         sb->s_op = &jffs2_super_operations;
316         sb->s_export_op = &jffs2_export_ops;
317         sb->s_flags = sb->s_flags | MS_NOATIME;
318         sb->s_xattr = jffs2_xattr_handlers;
319 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
320         sb->s_flags |= MS_POSIXACL;
321 #endif
322         ret = jffs2_do_fill_super(sb, data, silent);
323         return ret;
324 }
325
326 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
327                         int flags, const char *dev_name,
328                         void *data)
329 {
330         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
331 }
332
333 static void jffs2_put_super (struct super_block *sb)
334 {
335         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
336
337         jffs2_dbg(2, "%s()\n", __func__);
338
339         if (sb->s_dirt)
340                 jffs2_write_super(sb);
341
342         mutex_lock(&c->alloc_sem);
343         jffs2_flush_wbuf_pad(c);
344         mutex_unlock(&c->alloc_sem);
345
346         jffs2_sum_exit(c);
347
348         jffs2_free_ino_caches(c);
349         jffs2_free_raw_node_refs(c);
350         if (jffs2_blocks_use_vmalloc(c))
351                 vfree(c->blocks);
352         else
353                 kfree(c->blocks);
354         jffs2_flash_cleanup(c);
355         kfree(c->inocache_list);
356         jffs2_clear_xattr_subsystem(c);
357         mtd_sync(c->mtd);
358         jffs2_dbg(1, "%s(): returning\n", __func__);
359 }
360
361 static void jffs2_kill_sb(struct super_block *sb)
362 {
363         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
364         if (!(sb->s_flags & MS_RDONLY))
365                 jffs2_stop_garbage_collect_thread(c);
366         kill_mtd_super(sb);
367         kfree(c);
368 }
369
370 static struct file_system_type jffs2_fs_type = {
371         .owner =        THIS_MODULE,
372         .name =         "jffs2",
373         .mount =        jffs2_mount,
374         .kill_sb =      jffs2_kill_sb,
375 };
376
377 static int __init init_jffs2_fs(void)
378 {
379         int ret;
380
381         /* Paranoia checks for on-medium structures. If we ask GCC
382            to pack them with __attribute__((packed)) then it _also_
383            assumes that they're not aligned -- so it emits crappy
384            code on some architectures. Ideally we want an attribute
385            which means just 'no padding', without the alignment
386            thing. But GCC doesn't have that -- we have to just
387            hope the structs are the right sizes, instead. */
388         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
389         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
390         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
391         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
392
393         pr_info("version 2.2."
394 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
395                " (NAND)"
396 #endif
397 #ifdef CONFIG_JFFS2_SUMMARY
398                " (SUMMARY) "
399 #endif
400                " © 2001-2006 Red Hat, Inc.\n");
401
402         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
403                                              sizeof(struct jffs2_inode_info),
404                                              0, (SLAB_RECLAIM_ACCOUNT|
405                                                 SLAB_MEM_SPREAD),
406                                              jffs2_i_init_once);
407         if (!jffs2_inode_cachep) {
408                 pr_err("error: Failed to initialise inode cache\n");
409                 return -ENOMEM;
410         }
411         ret = jffs2_compressors_init();
412         if (ret) {
413                 pr_err("error: Failed to initialise compressors\n");
414                 goto out;
415         }
416         ret = jffs2_create_slab_caches();
417         if (ret) {
418                 pr_err("error: Failed to initialise slab caches\n");
419                 goto out_compressors;
420         }
421         ret = register_filesystem(&jffs2_fs_type);
422         if (ret) {
423                 pr_err("error: Failed to register filesystem\n");
424                 goto out_slab;
425         }
426         return 0;
427
428  out_slab:
429         jffs2_destroy_slab_caches();
430  out_compressors:
431         jffs2_compressors_exit();
432  out:
433         kmem_cache_destroy(jffs2_inode_cachep);
434         return ret;
435 }
436
437 static void __exit exit_jffs2_fs(void)
438 {
439         unregister_filesystem(&jffs2_fs_type);
440         jffs2_destroy_slab_caches();
441         jffs2_compressors_exit();
442         kmem_cache_destroy(jffs2_inode_cachep);
443 }
444
445 module_init(init_jffs2_fs);
446 module_exit(exit_jffs2_fs);
447
448 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
449 MODULE_AUTHOR("Red Hat, Inc.");
450 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
451                        // the sake of this tag. It's Free Software.