xref: /openbmc/linux/fs/jffs2/super.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright (C) 2001-2003 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  * $Id: super.c,v 1.107 2005/07/12 16:37:08 dedekind Exp $
11  *
12  */
13 
14 #include <linux/config.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/list.h>
20 #include <linux/fs.h>
21 #include <linux/mount.h>
22 #include <linux/jffs2.h>
23 #include <linux/pagemap.h>
24 #include <linux/mtd/mtd.h>
25 #include <linux/ctype.h>
26 #include <linux/namei.h>
27 #include "compr.h"
28 #include "nodelist.h"
29 
30 static void jffs2_put_super(struct super_block *);
31 
32 static kmem_cache_t *jffs2_inode_cachep;
33 
34 static struct inode *jffs2_alloc_inode(struct super_block *sb)
35 {
36 	struct jffs2_inode_info *ei;
37 	ei = (struct jffs2_inode_info *)kmem_cache_alloc(jffs2_inode_cachep, SLAB_KERNEL);
38 	if (!ei)
39 		return NULL;
40 	return &ei->vfs_inode;
41 }
42 
43 static void jffs2_destroy_inode(struct inode *inode)
44 {
45 	kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
46 }
47 
48 static void jffs2_i_init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
49 {
50 	struct jffs2_inode_info *ei = (struct jffs2_inode_info *) foo;
51 
52 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
53 	    SLAB_CTOR_CONSTRUCTOR) {
54 		init_MUTEX_LOCKED(&ei->sem);
55 		inode_init_once(&ei->vfs_inode);
56 	}
57 }
58 
59 static int jffs2_sync_fs(struct super_block *sb, int wait)
60 {
61 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
62 
63 	down(&c->alloc_sem);
64 	jffs2_flush_wbuf_pad(c);
65 	up(&c->alloc_sem);
66 	return 0;
67 }
68 
69 static struct super_operations jffs2_super_operations =
70 {
71 	.alloc_inode =	jffs2_alloc_inode,
72 	.destroy_inode =jffs2_destroy_inode,
73 	.read_inode =	jffs2_read_inode,
74 	.put_super =	jffs2_put_super,
75 	.write_super =	jffs2_write_super,
76 	.statfs =	jffs2_statfs,
77 	.remount_fs =	jffs2_remount_fs,
78 	.clear_inode =	jffs2_clear_inode,
79 	.dirty_inode =	jffs2_dirty_inode,
80 	.sync_fs =	jffs2_sync_fs,
81 };
82 
83 static int jffs2_sb_compare(struct super_block *sb, void *data)
84 {
85 	struct jffs2_sb_info *p = data;
86 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
87 
88 	/* The superblocks are considered to be equivalent if the underlying MTD
89 	   device is the same one */
90 	if (c->mtd == p->mtd) {
91 		D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d (\"%s\")\n", p->mtd->index, p->mtd->name));
92 		return 1;
93 	} else {
94 		D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d (\"%s\"), device %d (\"%s\")\n",
95 			  c->mtd->index, c->mtd->name, p->mtd->index, p->mtd->name));
96 		return 0;
97 	}
98 }
99 
100 static int jffs2_sb_set(struct super_block *sb, void *data)
101 {
102 	struct jffs2_sb_info *p = data;
103 
104 	/* For persistence of NFS exports etc. we use the same s_dev
105 	   each time we mount the device, don't just use an anonymous
106 	   device */
107 	sb->s_fs_info = p;
108 	p->os_priv = sb;
109 	sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
110 
111 	return 0;
112 }
113 
114 static struct super_block *jffs2_get_sb_mtd(struct file_system_type *fs_type,
115 					      int flags, const char *dev_name,
116 					      void *data, struct mtd_info *mtd)
117 {
118 	struct super_block *sb;
119 	struct jffs2_sb_info *c;
120 	int ret;
121 
122 	c = kmalloc(sizeof(*c), GFP_KERNEL);
123 	if (!c)
124 		return ERR_PTR(-ENOMEM);
125 	memset(c, 0, sizeof(*c));
126 	c->mtd = mtd;
127 
128 	sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
129 
130 	if (IS_ERR(sb))
131 		goto out_put;
132 
133 	if (sb->s_root) {
134 		/* New mountpoint for JFFS2 which is already mounted */
135 		D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is already mounted\n",
136 			  mtd->index, mtd->name));
137 		goto out_put;
138 	}
139 
140 	D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
141 		  mtd->index, mtd->name));
142 
143 	/* Initialize JFFS2 superblock locks, the further initialization will be
144 	 * done later */
145 	init_MUTEX(&c->alloc_sem);
146 	init_MUTEX(&c->erase_free_sem);
147 	init_waitqueue_head(&c->erase_wait);
148 	init_waitqueue_head(&c->inocache_wq);
149 	spin_lock_init(&c->erase_completion_lock);
150 	spin_lock_init(&c->inocache_lock);
151 
152 	sb->s_op = &jffs2_super_operations;
153 	sb->s_flags = flags | MS_NOATIME;
154 
155 	ret = jffs2_do_fill_super(sb, data, (flags&MS_VERBOSE)?1:0);
156 
157 	if (ret) {
158 		/* Failure case... */
159 		up_write(&sb->s_umount);
160 		deactivate_super(sb);
161 		return ERR_PTR(ret);
162 	}
163 
164 	sb->s_flags |= MS_ACTIVE;
165 	return sb;
166 
167  out_put:
168 	kfree(c);
169 	put_mtd_device(mtd);
170 
171 	return sb;
172 }
173 
174 static struct super_block *jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
175 					      int flags, const char *dev_name,
176 					      void *data, int mtdnr)
177 {
178 	struct mtd_info *mtd;
179 
180 	mtd = get_mtd_device(NULL, mtdnr);
181 	if (!mtd) {
182 		D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
183 		return ERR_PTR(-EINVAL);
184 	}
185 
186 	return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
187 }
188 
189 static struct super_block *jffs2_get_sb(struct file_system_type *fs_type,
190 					int flags, const char *dev_name,
191 					void *data)
192 {
193 	int err;
194 	struct nameidata nd;
195 	int mtdnr;
196 
197 	if (!dev_name)
198 		return ERR_PTR(-EINVAL);
199 
200 	D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
201 
202 	/* The preferred way of mounting in future; especially when
203 	   CONFIG_BLK_DEV is implemented - we specify the underlying
204 	   MTD device by number or by name, so that we don't require
205 	   block device support to be present in the kernel. */
206 
207 	/* FIXME: How to do the root fs this way? */
208 
209 	if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
210 		/* Probably mounting without the blkdev crap */
211 		if (dev_name[3] == ':') {
212 			struct mtd_info *mtd;
213 
214 			/* Mount by MTD device name */
215 			D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
216 			for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
217 				mtd = get_mtd_device(NULL, mtdnr);
218 				if (mtd) {
219 					if (!strcmp(mtd->name, dev_name+4))
220 						return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
221 					put_mtd_device(mtd);
222 				}
223 			}
224 			printk(KERN_NOTICE "jffs2_get_sb(): MTD device with name \"%s\" not found.\n", dev_name+4);
225 		} else if (isdigit(dev_name[3])) {
226 			/* Mount by MTD device number name */
227 			char *endptr;
228 
229 			mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
230 			if (!*endptr) {
231 				/* It was a valid number */
232 				D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
233 				return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
234 			}
235 		}
236 	}
237 
238 	/* Try the old way - the hack where we allowed users to mount
239 	   /dev/mtdblock$(n) but didn't actually _use_ the blkdev */
240 
241 	err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
242 
243 	D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
244 		  err, nd.dentry->d_inode));
245 
246 	if (err)
247 		return ERR_PTR(err);
248 
249 	err = -EINVAL;
250 
251 	if (!S_ISBLK(nd.dentry->d_inode->i_mode))
252 		goto out;
253 
254 	if (nd.mnt->mnt_flags & MNT_NODEV) {
255 		err = -EACCES;
256 		goto out;
257 	}
258 
259 	if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
260 		if (!(flags & MS_VERBOSE)) /* Yes I mean this. Strangely */
261 			printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
262 			       dev_name);
263 		goto out;
264 	}
265 
266 	mtdnr = iminor(nd.dentry->d_inode);
267 	path_release(&nd);
268 
269 	return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
270 
271 out:
272 	path_release(&nd);
273 	return ERR_PTR(err);
274 }
275 
276 static void jffs2_put_super (struct super_block *sb)
277 {
278 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
279 
280 	D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
281 
282 	down(&c->alloc_sem);
283 	jffs2_flush_wbuf_pad(c);
284 	up(&c->alloc_sem);
285 	jffs2_free_ino_caches(c);
286 	jffs2_free_raw_node_refs(c);
287 	if (c->mtd->flags & MTD_NO_VIRTBLOCKS)
288 		vfree(c->blocks);
289 	else
290 		kfree(c->blocks);
291 	jffs2_flash_cleanup(c);
292 	kfree(c->inocache_list);
293 	if (c->mtd->sync)
294 		c->mtd->sync(c->mtd);
295 
296 	D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
297 }
298 
299 static void jffs2_kill_sb(struct super_block *sb)
300 {
301 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
302 	if (!(sb->s_flags & MS_RDONLY))
303 		jffs2_stop_garbage_collect_thread(c);
304 	generic_shutdown_super(sb);
305 	put_mtd_device(c->mtd);
306 	kfree(c);
307 }
308 
309 static struct file_system_type jffs2_fs_type = {
310 	.owner =	THIS_MODULE,
311 	.name =		"jffs2",
312 	.get_sb =	jffs2_get_sb,
313 	.kill_sb =	jffs2_kill_sb,
314 };
315 
316 static int __init init_jffs2_fs(void)
317 {
318 	int ret;
319 
320 	printk(KERN_INFO "JFFS2 version 2.2."
321 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
322 	       " (NAND)"
323 #endif
324 	       " (C) 2001-2003 Red Hat, Inc.\n");
325 
326 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
327 					     sizeof(struct jffs2_inode_info),
328 					     0, SLAB_RECLAIM_ACCOUNT,
329 					     jffs2_i_init_once, NULL);
330 	if (!jffs2_inode_cachep) {
331 		printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
332 		return -ENOMEM;
333 	}
334 	ret = jffs2_compressors_init();
335 	if (ret) {
336 		printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
337 		goto out;
338 	}
339 	ret = jffs2_create_slab_caches();
340 	if (ret) {
341 		printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
342 		goto out_compressors;
343 	}
344 	ret = register_filesystem(&jffs2_fs_type);
345 	if (ret) {
346 		printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
347 		goto out_slab;
348 	}
349 	return 0;
350 
351  out_slab:
352 	jffs2_destroy_slab_caches();
353  out_compressors:
354 	jffs2_compressors_exit();
355  out:
356 	kmem_cache_destroy(jffs2_inode_cachep);
357 	return ret;
358 }
359 
360 static void __exit exit_jffs2_fs(void)
361 {
362 	unregister_filesystem(&jffs2_fs_type);
363 	jffs2_destroy_slab_caches();
364 	jffs2_compressors_exit();
365 	kmem_cache_destroy(jffs2_inode_cachep);
366 }
367 
368 module_init(init_jffs2_fs);
369 module_exit(exit_jffs2_fs);
370 
371 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
372 MODULE_AUTHOR("Red Hat, Inc.");
373 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
374 		       // the sake of this tag. It's Free Software.
375