xref: /openbmc/linux/fs/jffs2/fs.c (revision e290ed81)
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright © 2001-2007 Red Hat, Inc.
5  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
6  *
7  * Created by David Woodhouse <dwmw2@infradead.org>
8  *
9  * For licensing information, see the file 'LICENCE' in this directory.
10  *
11  */
12 
13 #include <linux/capability.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/fs.h>
17 #include <linux/list.h>
18 #include <linux/mtd/mtd.h>
19 #include <linux/pagemap.h>
20 #include <linux/slab.h>
21 #include <linux/vmalloc.h>
22 #include <linux/vfs.h>
23 #include <linux/crc32.h>
24 #include "nodelist.h"
25 
26 static int jffs2_flash_setup(struct jffs2_sb_info *c);
27 
28 int jffs2_do_setattr (struct inode *inode, struct iattr *iattr)
29 {
30 	struct jffs2_full_dnode *old_metadata, *new_metadata;
31 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
32 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
33 	struct jffs2_raw_inode *ri;
34 	union jffs2_device_node dev;
35 	unsigned char *mdata = NULL;
36 	int mdatalen = 0;
37 	unsigned int ivalid;
38 	uint32_t alloclen;
39 	int ret;
40 	int alloc_type = ALLOC_NORMAL;
41 
42 	D1(printk(KERN_DEBUG "jffs2_setattr(): ino #%lu\n", inode->i_ino));
43 
44 	/* Special cases - we don't want more than one data node
45 	   for these types on the medium at any time. So setattr
46 	   must read the original data associated with the node
47 	   (i.e. the device numbers or the target name) and write
48 	   it out again with the appropriate data attached */
49 	if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
50 		/* For these, we don't actually need to read the old node */
51 		mdatalen = jffs2_encode_dev(&dev, inode->i_rdev);
52 		mdata = (char *)&dev;
53 		D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of kdev_t\n", mdatalen));
54 	} else if (S_ISLNK(inode->i_mode)) {
55 		mutex_lock(&f->sem);
56 		mdatalen = f->metadata->size;
57 		mdata = kmalloc(f->metadata->size, GFP_USER);
58 		if (!mdata) {
59 			mutex_unlock(&f->sem);
60 			return -ENOMEM;
61 		}
62 		ret = jffs2_read_dnode(c, f, f->metadata, mdata, 0, mdatalen);
63 		if (ret) {
64 			mutex_unlock(&f->sem);
65 			kfree(mdata);
66 			return ret;
67 		}
68 		mutex_unlock(&f->sem);
69 		D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of symlink target\n", mdatalen));
70 	}
71 
72 	ri = jffs2_alloc_raw_inode();
73 	if (!ri) {
74 		if (S_ISLNK(inode->i_mode))
75 			kfree(mdata);
76 		return -ENOMEM;
77 	}
78 
79 	ret = jffs2_reserve_space(c, sizeof(*ri) + mdatalen, &alloclen,
80 				  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
81 	if (ret) {
82 		jffs2_free_raw_inode(ri);
83 		if (S_ISLNK(inode->i_mode))
84 			 kfree(mdata);
85 		return ret;
86 	}
87 	mutex_lock(&f->sem);
88 	ivalid = iattr->ia_valid;
89 
90 	ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
91 	ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
92 	ri->totlen = cpu_to_je32(sizeof(*ri) + mdatalen);
93 	ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));
94 
95 	ri->ino = cpu_to_je32(inode->i_ino);
96 	ri->version = cpu_to_je32(++f->highest_version);
97 
98 	ri->uid = cpu_to_je16((ivalid & ATTR_UID)?iattr->ia_uid:inode->i_uid);
99 	ri->gid = cpu_to_je16((ivalid & ATTR_GID)?iattr->ia_gid:inode->i_gid);
100 
101 	if (ivalid & ATTR_MODE)
102 		ri->mode = cpu_to_jemode(iattr->ia_mode);
103 	else
104 		ri->mode = cpu_to_jemode(inode->i_mode);
105 
106 
107 	ri->isize = cpu_to_je32((ivalid & ATTR_SIZE)?iattr->ia_size:inode->i_size);
108 	ri->atime = cpu_to_je32(I_SEC((ivalid & ATTR_ATIME)?iattr->ia_atime:inode->i_atime));
109 	ri->mtime = cpu_to_je32(I_SEC((ivalid & ATTR_MTIME)?iattr->ia_mtime:inode->i_mtime));
110 	ri->ctime = cpu_to_je32(I_SEC((ivalid & ATTR_CTIME)?iattr->ia_ctime:inode->i_ctime));
111 
112 	ri->offset = cpu_to_je32(0);
113 	ri->csize = ri->dsize = cpu_to_je32(mdatalen);
114 	ri->compr = JFFS2_COMPR_NONE;
115 	if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
116 		/* It's an extension. Make it a hole node */
117 		ri->compr = JFFS2_COMPR_ZERO;
118 		ri->dsize = cpu_to_je32(iattr->ia_size - inode->i_size);
119 		ri->offset = cpu_to_je32(inode->i_size);
120 	} else if (ivalid & ATTR_SIZE && !iattr->ia_size) {
121 		/* For truncate-to-zero, treat it as deletion because
122 		   it'll always be obsoleting all previous nodes */
123 		alloc_type = ALLOC_DELETION;
124 	}
125 	ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
126 	if (mdatalen)
127 		ri->data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
128 	else
129 		ri->data_crc = cpu_to_je32(0);
130 
131 	new_metadata = jffs2_write_dnode(c, f, ri, mdata, mdatalen, alloc_type);
132 	if (S_ISLNK(inode->i_mode))
133 		kfree(mdata);
134 
135 	if (IS_ERR(new_metadata)) {
136 		jffs2_complete_reservation(c);
137 		jffs2_free_raw_inode(ri);
138 		mutex_unlock(&f->sem);
139 		return PTR_ERR(new_metadata);
140 	}
141 	/* It worked. Update the inode */
142 	inode->i_atime = ITIME(je32_to_cpu(ri->atime));
143 	inode->i_ctime = ITIME(je32_to_cpu(ri->ctime));
144 	inode->i_mtime = ITIME(je32_to_cpu(ri->mtime));
145 	inode->i_mode = jemode_to_cpu(ri->mode);
146 	inode->i_uid = je16_to_cpu(ri->uid);
147 	inode->i_gid = je16_to_cpu(ri->gid);
148 
149 
150 	old_metadata = f->metadata;
151 
152 	if (ivalid & ATTR_SIZE && inode->i_size > iattr->ia_size)
153 		jffs2_truncate_fragtree (c, &f->fragtree, iattr->ia_size);
154 
155 	if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
156 		jffs2_add_full_dnode_to_inode(c, f, new_metadata);
157 		inode->i_size = iattr->ia_size;
158 		inode->i_blocks = (inode->i_size + 511) >> 9;
159 		f->metadata = NULL;
160 	} else {
161 		f->metadata = new_metadata;
162 	}
163 	if (old_metadata) {
164 		jffs2_mark_node_obsolete(c, old_metadata->raw);
165 		jffs2_free_full_dnode(old_metadata);
166 	}
167 	jffs2_free_raw_inode(ri);
168 
169 	mutex_unlock(&f->sem);
170 	jffs2_complete_reservation(c);
171 
172 	/* We have to do the truncate_setsize() without f->sem held, since
173 	   some pages may be locked and waiting for it in readpage().
174 	   We are protected from a simultaneous write() extending i_size
175 	   back past iattr->ia_size, because do_truncate() holds the
176 	   generic inode semaphore. */
177 	if (ivalid & ATTR_SIZE && inode->i_size > iattr->ia_size) {
178 		truncate_setsize(inode, iattr->ia_size);
179 		inode->i_blocks = (inode->i_size + 511) >> 9;
180 	}
181 
182 	return 0;
183 }
184 
185 int jffs2_setattr(struct dentry *dentry, struct iattr *iattr)
186 {
187 	int rc;
188 
189 	rc = inode_change_ok(dentry->d_inode, iattr);
190 	if (rc)
191 		return rc;
192 
193 	rc = jffs2_do_setattr(dentry->d_inode, iattr);
194 	if (!rc && (iattr->ia_valid & ATTR_MODE))
195 		rc = jffs2_acl_chmod(dentry->d_inode);
196 
197 	return rc;
198 }
199 
200 int jffs2_statfs(struct dentry *dentry, struct kstatfs *buf)
201 {
202 	struct jffs2_sb_info *c = JFFS2_SB_INFO(dentry->d_sb);
203 	unsigned long avail;
204 
205 	buf->f_type = JFFS2_SUPER_MAGIC;
206 	buf->f_bsize = 1 << PAGE_SHIFT;
207 	buf->f_blocks = c->flash_size >> PAGE_SHIFT;
208 	buf->f_files = 0;
209 	buf->f_ffree = 0;
210 	buf->f_namelen = JFFS2_MAX_NAME_LEN;
211 	buf->f_fsid.val[0] = JFFS2_SUPER_MAGIC;
212 	buf->f_fsid.val[1] = c->mtd->index;
213 
214 	spin_lock(&c->erase_completion_lock);
215 	avail = c->dirty_size + c->free_size;
216 	if (avail > c->sector_size * c->resv_blocks_write)
217 		avail -= c->sector_size * c->resv_blocks_write;
218 	else
219 		avail = 0;
220 	spin_unlock(&c->erase_completion_lock);
221 
222 	buf->f_bavail = buf->f_bfree = avail >> PAGE_SHIFT;
223 
224 	return 0;
225 }
226 
227 
228 void jffs2_evict_inode (struct inode *inode)
229 {
230 	/* We can forget about this inode for now - drop all
231 	 *  the nodelists associated with it, etc.
232 	 */
233 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
234 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
235 
236 	D1(printk(KERN_DEBUG "jffs2_evict_inode(): ino #%lu mode %o\n", inode->i_ino, inode->i_mode));
237 	truncate_inode_pages(&inode->i_data, 0);
238 	end_writeback(inode);
239 	jffs2_do_clear_inode(c, f);
240 }
241 
242 struct inode *jffs2_iget(struct super_block *sb, unsigned long ino)
243 {
244 	struct jffs2_inode_info *f;
245 	struct jffs2_sb_info *c;
246 	struct jffs2_raw_inode latest_node;
247 	union jffs2_device_node jdev;
248 	struct inode *inode;
249 	dev_t rdev = 0;
250 	int ret;
251 
252 	D1(printk(KERN_DEBUG "jffs2_iget(): ino == %lu\n", ino));
253 
254 	inode = iget_locked(sb, ino);
255 	if (!inode)
256 		return ERR_PTR(-ENOMEM);
257 	if (!(inode->i_state & I_NEW))
258 		return inode;
259 
260 	f = JFFS2_INODE_INFO(inode);
261 	c = JFFS2_SB_INFO(inode->i_sb);
262 
263 	jffs2_init_inode_info(f);
264 	mutex_lock(&f->sem);
265 
266 	ret = jffs2_do_read_inode(c, f, inode->i_ino, &latest_node);
267 
268 	if (ret) {
269 		mutex_unlock(&f->sem);
270 		iget_failed(inode);
271 		return ERR_PTR(ret);
272 	}
273 	inode->i_mode = jemode_to_cpu(latest_node.mode);
274 	inode->i_uid = je16_to_cpu(latest_node.uid);
275 	inode->i_gid = je16_to_cpu(latest_node.gid);
276 	inode->i_size = je32_to_cpu(latest_node.isize);
277 	inode->i_atime = ITIME(je32_to_cpu(latest_node.atime));
278 	inode->i_mtime = ITIME(je32_to_cpu(latest_node.mtime));
279 	inode->i_ctime = ITIME(je32_to_cpu(latest_node.ctime));
280 
281 	inode->i_nlink = f->inocache->pino_nlink;
282 
283 	inode->i_blocks = (inode->i_size + 511) >> 9;
284 
285 	switch (inode->i_mode & S_IFMT) {
286 
287 	case S_IFLNK:
288 		inode->i_op = &jffs2_symlink_inode_operations;
289 		break;
290 
291 	case S_IFDIR:
292 	{
293 		struct jffs2_full_dirent *fd;
294 		inode->i_nlink = 2; /* parent and '.' */
295 
296 		for (fd=f->dents; fd; fd = fd->next) {
297 			if (fd->type == DT_DIR && fd->ino)
298 				inc_nlink(inode);
299 		}
300 		/* Root dir gets i_nlink 3 for some reason */
301 		if (inode->i_ino == 1)
302 			inc_nlink(inode);
303 
304 		inode->i_op = &jffs2_dir_inode_operations;
305 		inode->i_fop = &jffs2_dir_operations;
306 		break;
307 	}
308 	case S_IFREG:
309 		inode->i_op = &jffs2_file_inode_operations;
310 		inode->i_fop = &jffs2_file_operations;
311 		inode->i_mapping->a_ops = &jffs2_file_address_operations;
312 		inode->i_mapping->nrpages = 0;
313 		break;
314 
315 	case S_IFBLK:
316 	case S_IFCHR:
317 		/* Read the device numbers from the media */
318 		if (f->metadata->size != sizeof(jdev.old_id) &&
319 		    f->metadata->size != sizeof(jdev.new_id)) {
320 			printk(KERN_NOTICE "Device node has strange size %d\n", f->metadata->size);
321 			goto error_io;
322 		}
323 		D1(printk(KERN_DEBUG "Reading device numbers from flash\n"));
324 		ret = jffs2_read_dnode(c, f, f->metadata, (char *)&jdev, 0, f->metadata->size);
325 		if (ret < 0) {
326 			/* Eep */
327 			printk(KERN_NOTICE "Read device numbers for inode %lu failed\n", (unsigned long)inode->i_ino);
328 			goto error;
329 		}
330 		if (f->metadata->size == sizeof(jdev.old_id))
331 			rdev = old_decode_dev(je16_to_cpu(jdev.old_id));
332 		else
333 			rdev = new_decode_dev(je32_to_cpu(jdev.new_id));
334 
335 	case S_IFSOCK:
336 	case S_IFIFO:
337 		inode->i_op = &jffs2_file_inode_operations;
338 		init_special_inode(inode, inode->i_mode, rdev);
339 		break;
340 
341 	default:
342 		printk(KERN_WARNING "jffs2_read_inode(): Bogus imode %o for ino %lu\n", inode->i_mode, (unsigned long)inode->i_ino);
343 	}
344 
345 	mutex_unlock(&f->sem);
346 
347 	D1(printk(KERN_DEBUG "jffs2_read_inode() returning\n"));
348 	unlock_new_inode(inode);
349 	return inode;
350 
351 error_io:
352 	ret = -EIO;
353 error:
354 	mutex_unlock(&f->sem);
355 	jffs2_do_clear_inode(c, f);
356 	iget_failed(inode);
357 	return ERR_PTR(ret);
358 }
359 
360 void jffs2_dirty_inode(struct inode *inode, int flags)
361 {
362 	struct iattr iattr;
363 
364 	if (!(inode->i_state & I_DIRTY_DATASYNC)) {
365 		D2(printk(KERN_DEBUG "jffs2_dirty_inode() not calling setattr() for ino #%lu\n", inode->i_ino));
366 		return;
367 	}
368 
369 	D1(printk(KERN_DEBUG "jffs2_dirty_inode() calling setattr() for ino #%lu\n", inode->i_ino));
370 
371 	iattr.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_MTIME|ATTR_CTIME;
372 	iattr.ia_mode = inode->i_mode;
373 	iattr.ia_uid = inode->i_uid;
374 	iattr.ia_gid = inode->i_gid;
375 	iattr.ia_atime = inode->i_atime;
376 	iattr.ia_mtime = inode->i_mtime;
377 	iattr.ia_ctime = inode->i_ctime;
378 
379 	jffs2_do_setattr(inode, &iattr);
380 }
381 
382 int jffs2_remount_fs (struct super_block *sb, int *flags, char *data)
383 {
384 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
385 
386 	if (c->flags & JFFS2_SB_FLAG_RO && !(sb->s_flags & MS_RDONLY))
387 		return -EROFS;
388 
389 	/* We stop if it was running, then restart if it needs to.
390 	   This also catches the case where it was stopped and this
391 	   is just a remount to restart it.
392 	   Flush the writebuffer, if neccecary, else we loose it */
393 	if (!(sb->s_flags & MS_RDONLY)) {
394 		jffs2_stop_garbage_collect_thread(c);
395 		mutex_lock(&c->alloc_sem);
396 		jffs2_flush_wbuf_pad(c);
397 		mutex_unlock(&c->alloc_sem);
398 	}
399 
400 	if (!(*flags & MS_RDONLY))
401 		jffs2_start_garbage_collect_thread(c);
402 
403 	*flags |= MS_NOATIME;
404 	return 0;
405 }
406 
407 /* jffs2_new_inode: allocate a new inode and inocache, add it to the hash,
408    fill in the raw_inode while you're at it. */
409 struct inode *jffs2_new_inode (struct inode *dir_i, umode_t mode, struct jffs2_raw_inode *ri)
410 {
411 	struct inode *inode;
412 	struct super_block *sb = dir_i->i_sb;
413 	struct jffs2_sb_info *c;
414 	struct jffs2_inode_info *f;
415 	int ret;
416 
417 	D1(printk(KERN_DEBUG "jffs2_new_inode(): dir_i %ld, mode 0x%x\n", dir_i->i_ino, mode));
418 
419 	c = JFFS2_SB_INFO(sb);
420 
421 	inode = new_inode(sb);
422 
423 	if (!inode)
424 		return ERR_PTR(-ENOMEM);
425 
426 	f = JFFS2_INODE_INFO(inode);
427 	jffs2_init_inode_info(f);
428 	mutex_lock(&f->sem);
429 
430 	memset(ri, 0, sizeof(*ri));
431 	/* Set OS-specific defaults for new inodes */
432 	ri->uid = cpu_to_je16(current_fsuid());
433 
434 	if (dir_i->i_mode & S_ISGID) {
435 		ri->gid = cpu_to_je16(dir_i->i_gid);
436 		if (S_ISDIR(mode))
437 			mode |= S_ISGID;
438 	} else {
439 		ri->gid = cpu_to_je16(current_fsgid());
440 	}
441 
442 	/* POSIX ACLs have to be processed now, at least partly.
443 	   The umask is only applied if there's no default ACL */
444 	ret = jffs2_init_acl_pre(dir_i, inode, &mode);
445 	if (ret) {
446 	    make_bad_inode(inode);
447 	    iput(inode);
448 	    return ERR_PTR(ret);
449 	}
450 	ret = jffs2_do_new_inode (c, f, mode, ri);
451 	if (ret) {
452 		make_bad_inode(inode);
453 		iput(inode);
454 		return ERR_PTR(ret);
455 	}
456 	inode->i_nlink = 1;
457 	inode->i_ino = je32_to_cpu(ri->ino);
458 	inode->i_mode = jemode_to_cpu(ri->mode);
459 	inode->i_gid = je16_to_cpu(ri->gid);
460 	inode->i_uid = je16_to_cpu(ri->uid);
461 	inode->i_atime = inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
462 	ri->atime = ri->mtime = ri->ctime = cpu_to_je32(I_SEC(inode->i_mtime));
463 
464 	inode->i_blocks = 0;
465 	inode->i_size = 0;
466 
467 	if (insert_inode_locked(inode) < 0) {
468 		make_bad_inode(inode);
469 		unlock_new_inode(inode);
470 		iput(inode);
471 		return ERR_PTR(-EINVAL);
472 	}
473 
474 	return inode;
475 }
476 
477 static int calculate_inocache_hashsize(uint32_t flash_size)
478 {
479 	/*
480 	 * Pick a inocache hash size based on the size of the medium.
481 	 * Count how many megabytes we're dealing with, apply a hashsize twice
482 	 * that size, but rounding down to the usual big powers of 2. And keep
483 	 * to sensible bounds.
484 	 */
485 
486 	int size_mb = flash_size / 1024 / 1024;
487 	int hashsize = (size_mb * 2) & ~0x3f;
488 
489 	if (hashsize < INOCACHE_HASHSIZE_MIN)
490 		return INOCACHE_HASHSIZE_MIN;
491 	if (hashsize > INOCACHE_HASHSIZE_MAX)
492 		return INOCACHE_HASHSIZE_MAX;
493 
494 	return hashsize;
495 }
496 
497 int jffs2_do_fill_super(struct super_block *sb, void *data, int silent)
498 {
499 	struct jffs2_sb_info *c;
500 	struct inode *root_i;
501 	int ret;
502 	size_t blocks;
503 
504 	c = JFFS2_SB_INFO(sb);
505 
506 #ifndef CONFIG_JFFS2_FS_WRITEBUFFER
507 	if (c->mtd->type == MTD_NANDFLASH) {
508 		printk(KERN_ERR "jffs2: Cannot operate on NAND flash unless jffs2 NAND support is compiled in.\n");
509 		return -EINVAL;
510 	}
511 	if (c->mtd->type == MTD_DATAFLASH) {
512 		printk(KERN_ERR "jffs2: Cannot operate on DataFlash unless jffs2 DataFlash support is compiled in.\n");
513 		return -EINVAL;
514 	}
515 #endif
516 
517 	c->flash_size = c->mtd->size;
518 	c->sector_size = c->mtd->erasesize;
519 	blocks = c->flash_size / c->sector_size;
520 
521 	/*
522 	 * Size alignment check
523 	 */
524 	if ((c->sector_size * blocks) != c->flash_size) {
525 		c->flash_size = c->sector_size * blocks;
526 		printk(KERN_INFO "jffs2: Flash size not aligned to erasesize, reducing to %dKiB\n",
527 			c->flash_size / 1024);
528 	}
529 
530 	if (c->flash_size < 5*c->sector_size) {
531 		printk(KERN_ERR "jffs2: Too few erase blocks (%d)\n", c->flash_size / c->sector_size);
532 		return -EINVAL;
533 	}
534 
535 	c->cleanmarker_size = sizeof(struct jffs2_unknown_node);
536 
537 	/* NAND (or other bizarre) flash... do setup accordingly */
538 	ret = jffs2_flash_setup(c);
539 	if (ret)
540 		return ret;
541 
542 	c->inocache_hashsize = calculate_inocache_hashsize(c->flash_size);
543 	c->inocache_list = kcalloc(c->inocache_hashsize, sizeof(struct jffs2_inode_cache *), GFP_KERNEL);
544 	if (!c->inocache_list) {
545 		ret = -ENOMEM;
546 		goto out_wbuf;
547 	}
548 
549 	jffs2_init_xattr_subsystem(c);
550 
551 	if ((ret = jffs2_do_mount_fs(c)))
552 		goto out_inohash;
553 
554 	D1(printk(KERN_DEBUG "jffs2_do_fill_super(): Getting root inode\n"));
555 	root_i = jffs2_iget(sb, 1);
556 	if (IS_ERR(root_i)) {
557 		D1(printk(KERN_WARNING "get root inode failed\n"));
558 		ret = PTR_ERR(root_i);
559 		goto out_root;
560 	}
561 
562 	ret = -ENOMEM;
563 
564 	D1(printk(KERN_DEBUG "jffs2_do_fill_super(): d_alloc_root()\n"));
565 	sb->s_root = d_alloc_root(root_i);
566 	if (!sb->s_root)
567 		goto out_root_i;
568 
569 	sb->s_maxbytes = 0xFFFFFFFF;
570 	sb->s_blocksize = PAGE_CACHE_SIZE;
571 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
572 	sb->s_magic = JFFS2_SUPER_MAGIC;
573 	if (!(sb->s_flags & MS_RDONLY))
574 		jffs2_start_garbage_collect_thread(c);
575 	return 0;
576 
577  out_root_i:
578 	iput(root_i);
579 out_root:
580 	jffs2_free_ino_caches(c);
581 	jffs2_free_raw_node_refs(c);
582 	if (jffs2_blocks_use_vmalloc(c))
583 		vfree(c->blocks);
584 	else
585 		kfree(c->blocks);
586  out_inohash:
587 	jffs2_clear_xattr_subsystem(c);
588 	kfree(c->inocache_list);
589  out_wbuf:
590 	jffs2_flash_cleanup(c);
591 
592 	return ret;
593 }
594 
595 void jffs2_gc_release_inode(struct jffs2_sb_info *c,
596 				   struct jffs2_inode_info *f)
597 {
598 	iput(OFNI_EDONI_2SFFJ(f));
599 }
600 
601 struct jffs2_inode_info *jffs2_gc_fetch_inode(struct jffs2_sb_info *c,
602 					      int inum, int unlinked)
603 {
604 	struct inode *inode;
605 	struct jffs2_inode_cache *ic;
606 
607 	if (unlinked) {
608 		/* The inode has zero nlink but its nodes weren't yet marked
609 		   obsolete. This has to be because we're still waiting for
610 		   the final (close() and) iput() to happen.
611 
612 		   There's a possibility that the final iput() could have
613 		   happened while we were contemplating. In order to ensure
614 		   that we don't cause a new read_inode() (which would fail)
615 		   for the inode in question, we use ilookup() in this case
616 		   instead of iget().
617 
618 		   The nlink can't _become_ zero at this point because we're
619 		   holding the alloc_sem, and jffs2_do_unlink() would also
620 		   need that while decrementing nlink on any inode.
621 		*/
622 		inode = ilookup(OFNI_BS_2SFFJ(c), inum);
623 		if (!inode) {
624 			D1(printk(KERN_DEBUG "ilookup() failed for ino #%u; inode is probably deleted.\n",
625 				  inum));
626 
627 			spin_lock(&c->inocache_lock);
628 			ic = jffs2_get_ino_cache(c, inum);
629 			if (!ic) {
630 				D1(printk(KERN_DEBUG "Inode cache for ino #%u is gone.\n", inum));
631 				spin_unlock(&c->inocache_lock);
632 				return NULL;
633 			}
634 			if (ic->state != INO_STATE_CHECKEDABSENT) {
635 				/* Wait for progress. Don't just loop */
636 				D1(printk(KERN_DEBUG "Waiting for ino #%u in state %d\n",
637 					  ic->ino, ic->state));
638 				sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
639 			} else {
640 				spin_unlock(&c->inocache_lock);
641 			}
642 
643 			return NULL;
644 		}
645 	} else {
646 		/* Inode has links to it still; they're not going away because
647 		   jffs2_do_unlink() would need the alloc_sem and we have it.
648 		   Just iget() it, and if read_inode() is necessary that's OK.
649 		*/
650 		inode = jffs2_iget(OFNI_BS_2SFFJ(c), inum);
651 		if (IS_ERR(inode))
652 			return ERR_CAST(inode);
653 	}
654 	if (is_bad_inode(inode)) {
655 		printk(KERN_NOTICE "Eep. read_inode() failed for ino #%u. unlinked %d\n",
656 		       inum, unlinked);
657 		/* NB. This will happen again. We need to do something appropriate here. */
658 		iput(inode);
659 		return ERR_PTR(-EIO);
660 	}
661 
662 	return JFFS2_INODE_INFO(inode);
663 }
664 
665 unsigned char *jffs2_gc_fetch_page(struct jffs2_sb_info *c,
666 				   struct jffs2_inode_info *f,
667 				   unsigned long offset,
668 				   unsigned long *priv)
669 {
670 	struct inode *inode = OFNI_EDONI_2SFFJ(f);
671 	struct page *pg;
672 
673 	pg = read_cache_page_async(inode->i_mapping, offset >> PAGE_CACHE_SHIFT,
674 			     (void *)jffs2_do_readpage_unlock, inode);
675 	if (IS_ERR(pg))
676 		return (void *)pg;
677 
678 	*priv = (unsigned long)pg;
679 	return kmap(pg);
680 }
681 
682 void jffs2_gc_release_page(struct jffs2_sb_info *c,
683 			   unsigned char *ptr,
684 			   unsigned long *priv)
685 {
686 	struct page *pg = (void *)*priv;
687 
688 	kunmap(pg);
689 	page_cache_release(pg);
690 }
691 
692 static int jffs2_flash_setup(struct jffs2_sb_info *c) {
693 	int ret = 0;
694 
695 	if (jffs2_cleanmarker_oob(c)) {
696 		/* NAND flash... do setup accordingly */
697 		ret = jffs2_nand_flash_setup(c);
698 		if (ret)
699 			return ret;
700 	}
701 
702 	/* and Dataflash */
703 	if (jffs2_dataflash(c)) {
704 		ret = jffs2_dataflash_setup(c);
705 		if (ret)
706 			return ret;
707 	}
708 
709 	/* and Intel "Sibley" flash */
710 	if (jffs2_nor_wbuf_flash(c)) {
711 		ret = jffs2_nor_wbuf_flash_setup(c);
712 		if (ret)
713 			return ret;
714 	}
715 
716 	/* and an UBI volume */
717 	if (jffs2_ubivol(c)) {
718 		ret = jffs2_ubivol_setup(c);
719 		if (ret)
720 			return ret;
721 	}
722 
723 	return ret;
724 }
725 
726 void jffs2_flash_cleanup(struct jffs2_sb_info *c) {
727 
728 	if (jffs2_cleanmarker_oob(c)) {
729 		jffs2_nand_flash_cleanup(c);
730 	}
731 
732 	/* and DataFlash */
733 	if (jffs2_dataflash(c)) {
734 		jffs2_dataflash_cleanup(c);
735 	}
736 
737 	/* and Intel "Sibley" flash */
738 	if (jffs2_nor_wbuf_flash(c)) {
739 		jffs2_nor_wbuf_flash_cleanup(c);
740 	}
741 
742 	/* and an UBI volume */
743 	if (jffs2_ubivol(c)) {
744 		jffs2_ubivol_cleanup(c);
745 	}
746 }
747