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Linux/fs/jffs2/super.c

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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/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         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 
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 
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 
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 
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_override_compr: override default compressor
163  * Opt_rp_size: size of reserved pool in KiB
164  * Opt_err: just end of array marker
165  */
166 enum {
167         Opt_override_compr,
168         Opt_rp_size,
169         Opt_err,
170 };
171 
172 static const match_table_t tokens = {
173         {Opt_override_compr, "compr=%s"},
174         {Opt_rp_size, "rp_size=%u"},
175         {Opt_err, NULL},
176 };
177 
178 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
179 {
180         substring_t args[MAX_OPT_ARGS];
181         char *p, *name;
182         unsigned int opt;
183 
184         if (!data)
185                 return 0;
186 
187         while ((p = strsep(&data, ","))) {
188                 int token;
189 
190                 if (!*p)
191                         continue;
192 
193                 token = match_token(p, tokens, args);
194                 switch (token) {
195                 case Opt_override_compr:
196                         name = match_strdup(&args[0]);
197 
198                         if (!name)
199                                 return -ENOMEM;
200                         if (!strcmp(name, "none"))
201                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
202 #ifdef CONFIG_JFFS2_LZO
203                         else if (!strcmp(name, "lzo"))
204                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
205 #endif
206 #ifdef CONFIG_JFFS2_ZLIB
207                         else if (!strcmp(name, "zlib"))
208                                 c->mount_opts.compr =
209                                                 JFFS2_COMPR_MODE_FORCEZLIB;
210 #endif
211                         else {
212                                 pr_err("Error: unknown compressor \"%s\"\n",
213                                        name);
214                                 kfree(name);
215                                 return -EINVAL;
216                         }
217                         kfree(name);
218                         c->mount_opts.override_compr = true;
219                         break;
220                 case Opt_rp_size:
221                         if (match_int(&args[0], &opt))
222                                 return -EINVAL;
223                         opt *= 1024;
224                         if (opt > c->mtd->size) {
225                                 pr_warn("Too large reserve pool specified, max "
226                                         "is %llu KB\n", c->mtd->size / 1024);
227                                 return -EINVAL;
228                         }
229                         c->mount_opts.rp_size = opt;
230                         break;
231                 default:
232                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
233                                p);
234                         return -EINVAL;
235                 }
236         }
237 
238         return 0;
239 }
240 
241 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
242 {
243         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
244         int err;
245 
246         sync_filesystem(sb);
247         err = jffs2_parse_options(c, data);
248         if (err)
249                 return -EINVAL;
250 
251         return jffs2_do_remount_fs(sb, flags, data);
252 }
253 
254 static const struct super_operations jffs2_super_operations =
255 {
256         .alloc_inode =  jffs2_alloc_inode,
257         .destroy_inode =jffs2_destroy_inode,
258         .put_super =    jffs2_put_super,
259         .statfs =       jffs2_statfs,
260         .remount_fs =   jffs2_remount_fs,
261         .evict_inode =  jffs2_evict_inode,
262         .dirty_inode =  jffs2_dirty_inode,
263         .show_options = jffs2_show_options,
264         .sync_fs =      jffs2_sync_fs,
265 };
266 
267 /*
268  * fill in the superblock
269  */
270 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
271 {
272         struct jffs2_sb_info *c;
273         int ret;
274 
275         jffs2_dbg(1, "jffs2_get_sb_mtd():"
276                   " New superblock for device %d (\"%s\")\n",
277                   sb->s_mtd->index, sb->s_mtd->name);
278 
279         c = kzalloc(sizeof(*c), GFP_KERNEL);
280         if (!c)
281                 return -ENOMEM;
282 
283         c->mtd = sb->s_mtd;
284         c->os_priv = sb;
285         sb->s_fs_info = c;
286 
287         ret = jffs2_parse_options(c, data);
288         if (ret) {
289                 kfree(c);
290                 return -EINVAL;
291         }
292 
293         /* Initialize JFFS2 superblock locks, the further initialization will
294          * be done later */
295         mutex_init(&c->alloc_sem);
296         mutex_init(&c->erase_free_sem);
297         init_waitqueue_head(&c->erase_wait);
298         init_waitqueue_head(&c->inocache_wq);
299         spin_lock_init(&c->erase_completion_lock);
300         spin_lock_init(&c->inocache_lock);
301 
302         sb->s_op = &jffs2_super_operations;
303         sb->s_export_op = &jffs2_export_ops;
304         sb->s_flags = sb->s_flags | MS_NOATIME;
305         sb->s_xattr = jffs2_xattr_handlers;
306 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
307         sb->s_flags |= MS_POSIXACL;
308 #endif
309         ret = jffs2_do_fill_super(sb, data, silent);
310         return ret;
311 }
312 
313 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
314                         int flags, const char *dev_name,
315                         void *data)
316 {
317         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
318 }
319 
320 static void jffs2_put_super (struct super_block *sb)
321 {
322         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
323 
324         jffs2_dbg(2, "%s()\n", __func__);
325 
326         mutex_lock(&c->alloc_sem);
327         jffs2_flush_wbuf_pad(c);
328         mutex_unlock(&c->alloc_sem);
329 
330         jffs2_sum_exit(c);
331 
332         jffs2_free_ino_caches(c);
333         jffs2_free_raw_node_refs(c);
334         kvfree(c->blocks);
335         jffs2_flash_cleanup(c);
336         kfree(c->inocache_list);
337         jffs2_clear_xattr_subsystem(c);
338         mtd_sync(c->mtd);
339         jffs2_dbg(1, "%s(): returning\n", __func__);
340 }
341 
342 static void jffs2_kill_sb(struct super_block *sb)
343 {
344         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
345         if (!(sb->s_flags & MS_RDONLY))
346                 jffs2_stop_garbage_collect_thread(c);
347         kill_mtd_super(sb);
348         kfree(c);
349 }
350 
351 static struct file_system_type jffs2_fs_type = {
352         .owner =        THIS_MODULE,
353         .name =         "jffs2",
354         .mount =        jffs2_mount,
355         .kill_sb =      jffs2_kill_sb,
356 };
357 MODULE_ALIAS_FS("jffs2");
358 
359 static int __init init_jffs2_fs(void)
360 {
361         int ret;
362 
363         /* Paranoia checks for on-medium structures. If we ask GCC
364            to pack them with __attribute__((packed)) then it _also_
365            assumes that they're not aligned -- so it emits crappy
366            code on some architectures. Ideally we want an attribute
367            which means just 'no padding', without the alignment
368            thing. But GCC doesn't have that -- we have to just
369            hope the structs are the right sizes, instead. */
370         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
371         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
372         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
373         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
374 
375         pr_info("version 2.2."
376 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
377                " (NAND)"
378 #endif
379 #ifdef CONFIG_JFFS2_SUMMARY
380                " (SUMMARY) "
381 #endif
382                " © 2001-2006 Red Hat, Inc.\n");
383 
384         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
385                                              sizeof(struct jffs2_inode_info),
386                                              0, (SLAB_RECLAIM_ACCOUNT|
387                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
388                                              jffs2_i_init_once);
389         if (!jffs2_inode_cachep) {
390                 pr_err("error: Failed to initialise inode cache\n");
391                 return -ENOMEM;
392         }
393         ret = jffs2_compressors_init();
394         if (ret) {
395                 pr_err("error: Failed to initialise compressors\n");
396                 goto out;
397         }
398         ret = jffs2_create_slab_caches();
399         if (ret) {
400                 pr_err("error: Failed to initialise slab caches\n");
401                 goto out_compressors;
402         }
403         ret = register_filesystem(&jffs2_fs_type);
404         if (ret) {
405                 pr_err("error: Failed to register filesystem\n");
406                 goto out_slab;
407         }
408         return 0;
409 
410  out_slab:
411         jffs2_destroy_slab_caches();
412  out_compressors:
413         jffs2_compressors_exit();
414  out:
415         kmem_cache_destroy(jffs2_inode_cachep);
416         return ret;
417 }
418 
419 static void __exit exit_jffs2_fs(void)
420 {
421         unregister_filesystem(&jffs2_fs_type);
422         jffs2_destroy_slab_caches();
423         jffs2_compressors_exit();
424 
425         /*
426          * Make sure all delayed rcu free inodes are flushed before we
427          * destroy cache.
428          */
429         rcu_barrier();
430         kmem_cache_destroy(jffs2_inode_cachep);
431 }
432 
433 module_init(init_jffs2_fs);
434 module_exit(exit_jffs2_fs);
435 
436 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
437 MODULE_AUTHOR("Red Hat, Inc.");
438 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
439                        // the sake of this tag. It's Free Software.
440 

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