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/fs/adfs/super.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 543 lines | 424 code | 82 blank | 37 comment | 68 complexity | 81e39e5bcc390aaeab50c36644e84118 MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  1/*
  2 *  linux/fs/adfs/super.c
  3 *
  4 *  Copyright (C) 1997-1999 Russell King
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License version 2 as
  8 * published by the Free Software Foundation.
  9 */
 10#include <linux/module.h>
 11#include <linux/init.h>
 12#include <linux/buffer_head.h>
 13#include <linux/parser.h>
 14#include <linux/mount.h>
 15#include <linux/seq_file.h>
 16#include <linux/slab.h>
 17#include <linux/statfs.h>
 18#include "adfs.h"
 19#include "dir_f.h"
 20#include "dir_fplus.h"
 21
 22#define ADFS_DEFAULT_OWNER_MASK S_IRWXU
 23#define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)
 24
 25void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 26{
 27	char error_buf[128];
 28	va_list args;
 29
 30	va_start(args, fmt);
 31	vsnprintf(error_buf, sizeof(error_buf), fmt, args);
 32	va_end(args);
 33
 34	printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
 35		sb->s_id, function ? ": " : "",
 36		function ? function : "", error_buf);
 37}
 38
 39static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
 40{
 41	int i;
 42
 43	/* sector size must be 256, 512 or 1024 bytes */
 44	if (dr->log2secsize != 8 &&
 45	    dr->log2secsize != 9 &&
 46	    dr->log2secsize != 10)
 47		return 1;
 48
 49	/* idlen must be at least log2secsize + 3 */
 50	if (dr->idlen < dr->log2secsize + 3)
 51		return 1;
 52
 53	/* we cannot have such a large disc that we
 54	 * are unable to represent sector offsets in
 55	 * 32 bits.  This works out at 2.0 TB.
 56	 */
 57	if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
 58		return 1;
 59
 60	/* idlen must be no greater than 19 v2 [1.0] */
 61	if (dr->idlen > 19)
 62		return 1;
 63
 64	/* reserved bytes should be zero */
 65	for (i = 0; i < sizeof(dr->unused52); i++)
 66		if (dr->unused52[i] != 0)
 67			return 1;
 68
 69	return 0;
 70}
 71
 72static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
 73{
 74	unsigned int v0, v1, v2, v3;
 75	int i;
 76
 77	v0 = v1 = v2 = v3 = 0;
 78	for (i = sb->s_blocksize - 4; i; i -= 4) {
 79		v0 += map[i]     + (v3 >> 8);
 80		v3 &= 0xff;
 81		v1 += map[i + 1] + (v0 >> 8);
 82		v0 &= 0xff;
 83		v2 += map[i + 2] + (v1 >> 8);
 84		v1 &= 0xff;
 85		v3 += map[i + 3] + (v2 >> 8);
 86		v2 &= 0xff;
 87	}
 88	v0 +=           v3 >> 8;
 89	v1 += map[1] + (v0 >> 8);
 90	v2 += map[2] + (v1 >> 8);
 91	v3 += map[3] + (v2 >> 8);
 92
 93	return v0 ^ v1 ^ v2 ^ v3;
 94}
 95
 96static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
 97{
 98	unsigned char crosscheck = 0, zonecheck = 1;
 99	int i;
100
101	for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
102		unsigned char *map;
103
104		map = dm[i].dm_bh->b_data;
105
106		if (adfs_calczonecheck(sb, map) != map[0]) {
107			adfs_error(sb, "zone %d fails zonecheck", i);
108			zonecheck = 0;
109		}
110		crosscheck ^= map[3];
111	}
112	if (crosscheck != 0xff)
113		adfs_error(sb, "crosscheck != 0xff");
114	return crosscheck == 0xff && zonecheck;
115}
116
117static void adfs_put_super(struct super_block *sb)
118{
119	int i;
120	struct adfs_sb_info *asb = ADFS_SB(sb);
121
122	for (i = 0; i < asb->s_map_size; i++)
123		brelse(asb->s_map[i].dm_bh);
124	kfree(asb->s_map);
125	kfree(asb);
126	sb->s_fs_info = NULL;
127}
128
129static int adfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
130{
131	struct adfs_sb_info *asb = ADFS_SB(mnt->mnt_sb);
132
133	if (asb->s_uid != 0)
134		seq_printf(seq, ",uid=%u", asb->s_uid);
135	if (asb->s_gid != 0)
136		seq_printf(seq, ",gid=%u", asb->s_gid);
137	if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
138		seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
139	if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
140		seq_printf(seq, ",othmask=%o", asb->s_other_mask);
141	if (asb->s_ftsuffix != 0)
142		seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);
143
144	return 0;
145}
146
147enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};
148
149static const match_table_t tokens = {
150	{Opt_uid, "uid=%u"},
151	{Opt_gid, "gid=%u"},
152	{Opt_ownmask, "ownmask=%o"},
153	{Opt_othmask, "othmask=%o"},
154	{Opt_ftsuffix, "ftsuffix=%u"},
155	{Opt_err, NULL}
156};
157
158static int parse_options(struct super_block *sb, char *options)
159{
160	char *p;
161	struct adfs_sb_info *asb = ADFS_SB(sb);
162	int option;
163
164	if (!options)
165		return 0;
166
167	while ((p = strsep(&options, ",")) != NULL) {
168		substring_t args[MAX_OPT_ARGS];
169		int token;
170		if (!*p)
171			continue;
172
173		token = match_token(p, tokens, args);
174		switch (token) {
175		case Opt_uid:
176			if (match_int(args, &option))
177				return -EINVAL;
178			asb->s_uid = option;
179			break;
180		case Opt_gid:
181			if (match_int(args, &option))
182				return -EINVAL;
183			asb->s_gid = option;
184			break;
185		case Opt_ownmask:
186			if (match_octal(args, &option))
187				return -EINVAL;
188			asb->s_owner_mask = option;
189			break;
190		case Opt_othmask:
191			if (match_octal(args, &option))
192				return -EINVAL;
193			asb->s_other_mask = option;
194			break;
195		case Opt_ftsuffix:
196			if (match_int(args, &option))
197				return -EINVAL;
198			asb->s_ftsuffix = option;
199			break;
200		default:
201			printk("ADFS-fs: unrecognised mount option \"%s\" "
202					"or missing value\n", p);
203			return -EINVAL;
204		}
205	}
206	return 0;
207}
208
209static int adfs_remount(struct super_block *sb, int *flags, char *data)
210{
211	*flags |= MS_NODIRATIME;
212	return parse_options(sb, data);
213}
214
215static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
216{
217	struct super_block *sb = dentry->d_sb;
218	struct adfs_sb_info *sbi = ADFS_SB(sb);
219	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
220
221	buf->f_type    = ADFS_SUPER_MAGIC;
222	buf->f_namelen = sbi->s_namelen;
223	buf->f_bsize   = sb->s_blocksize;
224	buf->f_blocks  = sbi->s_size;
225	buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
226	buf->f_bavail  =
227	buf->f_bfree   = adfs_map_free(sb);
228	buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
229	buf->f_fsid.val[0] = (u32)id;
230	buf->f_fsid.val[1] = (u32)(id >> 32);
231
232	return 0;
233}
234
235static struct kmem_cache *adfs_inode_cachep;
236
237static struct inode *adfs_alloc_inode(struct super_block *sb)
238{
239	struct adfs_inode_info *ei;
240	ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
241	if (!ei)
242		return NULL;
243	return &ei->vfs_inode;
244}
245
246static void adfs_i_callback(struct rcu_head *head)
247{
248	struct inode *inode = container_of(head, struct inode, i_rcu);
249	INIT_LIST_HEAD(&inode->i_dentry);
250	kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
251}
252
253static void adfs_destroy_inode(struct inode *inode)
254{
255	call_rcu(&inode->i_rcu, adfs_i_callback);
256}
257
258static void init_once(void *foo)
259{
260	struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
261
262	inode_init_once(&ei->vfs_inode);
263}
264
265static int init_inodecache(void)
266{
267	adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
268					     sizeof(struct adfs_inode_info),
269					     0, (SLAB_RECLAIM_ACCOUNT|
270						SLAB_MEM_SPREAD),
271					     init_once);
272	if (adfs_inode_cachep == NULL)
273		return -ENOMEM;
274	return 0;
275}
276
277static void destroy_inodecache(void)
278{
279	kmem_cache_destroy(adfs_inode_cachep);
280}
281
282static const struct super_operations adfs_sops = {
283	.alloc_inode	= adfs_alloc_inode,
284	.destroy_inode	= adfs_destroy_inode,
285	.write_inode	= adfs_write_inode,
286	.put_super	= adfs_put_super,
287	.statfs		= adfs_statfs,
288	.remount_fs	= adfs_remount,
289	.show_options	= adfs_show_options,
290};
291
292static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
293{
294	struct adfs_discmap *dm;
295	unsigned int map_addr, zone_size, nzones;
296	int i, zone;
297	struct adfs_sb_info *asb = ADFS_SB(sb);
298
299	nzones    = asb->s_map_size;
300	zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
301	map_addr  = (nzones >> 1) * zone_size -
302		     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
303	map_addr  = signed_asl(map_addr, asb->s_map2blk);
304
305	asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
306
307	dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
308	if (dm == NULL) {
309		adfs_error(sb, "not enough memory");
310		return NULL;
311	}
312
313	for (zone = 0; zone < nzones; zone++, map_addr++) {
314		dm[zone].dm_startbit = 0;
315		dm[zone].dm_endbit   = zone_size;
316		dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
317		dm[zone].dm_bh       = sb_bread(sb, map_addr);
318
319		if (!dm[zone].dm_bh) {
320			adfs_error(sb, "unable to read map");
321			goto error_free;
322		}
323	}
324
325	/* adjust the limits for the first and last map zones */
326	i = zone - 1;
327	dm[0].dm_startblk = 0;
328	dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
329	dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
330			    (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
331			    (ADFS_DR_SIZE_BITS - i * zone_size);
332
333	if (adfs_checkmap(sb, dm))
334		return dm;
335
336	adfs_error(sb, "map corrupted");
337
338error_free:
339	while (--zone >= 0)
340		brelse(dm[zone].dm_bh);
341
342	kfree(dm);
343	return NULL;
344}
345
346static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
347{
348	unsigned long discsize;
349
350	discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
351	discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
352
353	return discsize;
354}
355
356static int adfs_fill_super(struct super_block *sb, void *data, int silent)
357{
358	struct adfs_discrecord *dr;
359	struct buffer_head *bh;
360	struct object_info root_obj;
361	unsigned char *b_data;
362	struct adfs_sb_info *asb;
363	struct inode *root;
364
365	sb->s_flags |= MS_NODIRATIME;
366
367	asb = kzalloc(sizeof(*asb), GFP_KERNEL);
368	if (!asb)
369		return -ENOMEM;
370	sb->s_fs_info = asb;
371
372	/* set default options */
373	asb->s_uid = 0;
374	asb->s_gid = 0;
375	asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
376	asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
377	asb->s_ftsuffix = 0;
378
379	if (parse_options(sb, data))
380		goto error;
381
382	sb_set_blocksize(sb, BLOCK_SIZE);
383	if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
384		adfs_error(sb, "unable to read superblock");
385		goto error;
386	}
387
388	b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
389
390	if (adfs_checkbblk(b_data)) {
391		if (!silent)
392			printk("VFS: Can't find an adfs filesystem on dev "
393				"%s.\n", sb->s_id);
394		goto error_free_bh;
395	}
396
397	dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
398
399	/*
400	 * Do some sanity checks on the ADFS disc record
401	 */
402	if (adfs_checkdiscrecord(dr)) {
403		if (!silent)
404			printk("VPS: Can't find an adfs filesystem on dev "
405				"%s.\n", sb->s_id);
406		goto error_free_bh;
407	}
408
409	brelse(bh);
410	if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
411		bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
412		if (!bh) {
413			adfs_error(sb, "couldn't read superblock on "
414				"2nd try.");
415			goto error;
416		}
417		b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
418		if (adfs_checkbblk(b_data)) {
419			adfs_error(sb, "disc record mismatch, very weird!");
420			goto error_free_bh;
421		}
422		dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
423	} else {
424		if (!silent)
425			printk(KERN_ERR "VFS: Unsupported blocksize on dev "
426				"%s.\n", sb->s_id);
427		goto error;
428	}
429
430	/*
431	 * blocksize on this device should now be set to the ADFS log2secsize
432	 */
433
434	sb->s_magic		= ADFS_SUPER_MAGIC;
435	asb->s_idlen		= dr->idlen;
436	asb->s_map_size		= dr->nzones | (dr->nzones_high << 8);
437	asb->s_map2blk		= dr->log2bpmb - dr->log2secsize;
438	asb->s_size    		= adfs_discsize(dr, sb->s_blocksize_bits);
439	asb->s_version 		= dr->format_version;
440	asb->s_log2sharesize	= dr->log2sharesize;
441	
442	asb->s_map = adfs_read_map(sb, dr);
443	if (!asb->s_map)
444		goto error_free_bh;
445
446	brelse(bh);
447
448	/*
449	 * set up enough so that we can read an inode
450	 */
451	sb->s_op = &adfs_sops;
452
453	dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
454
455	root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
456	root_obj.name_len  = 0;
457	/* Set root object date as 01 Jan 1987 00:00:00 */
458	root_obj.loadaddr  = 0xfff0003f;
459	root_obj.execaddr  = 0xec22c000;
460	root_obj.size	   = ADFS_NEWDIR_SIZE;
461	root_obj.attr	   = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
462			     ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
463	root_obj.filetype  = -1;
464
465	/*
466	 * If this is a F+ disk with variable length directories,
467	 * get the root_size from the disc record.
468	 */
469	if (asb->s_version) {
470		root_obj.size = le32_to_cpu(dr->root_size);
471		asb->s_dir     = &adfs_fplus_dir_ops;
472		asb->s_namelen = ADFS_FPLUS_NAME_LEN;
473	} else {
474		asb->s_dir     = &adfs_f_dir_ops;
475		asb->s_namelen = ADFS_F_NAME_LEN;
476	}
477	/*
478	 * ,xyz hex filetype suffix may be added by driver
479	 * to files that have valid RISC OS filetype
480	 */
481	if (asb->s_ftsuffix)
482		asb->s_namelen += 4;
483
484	sb->s_d_op = &adfs_dentry_operations;
485	root = adfs_iget(sb, &root_obj);
486	sb->s_root = d_alloc_root(root);
487	if (!sb->s_root) {
488		int i;
489		iput(root);
490		for (i = 0; i < asb->s_map_size; i++)
491			brelse(asb->s_map[i].dm_bh);
492		kfree(asb->s_map);
493		adfs_error(sb, "get root inode failed\n");
494		goto error;
495	}
496	return 0;
497
498error_free_bh:
499	brelse(bh);
500error:
501	sb->s_fs_info = NULL;
502	kfree(asb);
503	return -EINVAL;
504}
505
506static struct dentry *adfs_mount(struct file_system_type *fs_type,
507	int flags, const char *dev_name, void *data)
508{
509	return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
510}
511
512static struct file_system_type adfs_fs_type = {
513	.owner		= THIS_MODULE,
514	.name		= "adfs",
515	.mount		= adfs_mount,
516	.kill_sb	= kill_block_super,
517	.fs_flags	= FS_REQUIRES_DEV,
518};
519
520static int __init init_adfs_fs(void)
521{
522	int err = init_inodecache();
523	if (err)
524		goto out1;
525	err = register_filesystem(&adfs_fs_type);
526	if (err)
527		goto out;
528	return 0;
529out:
530	destroy_inodecache();
531out1:
532	return err;
533}
534
535static void __exit exit_adfs_fs(void)
536{
537	unregister_filesystem(&adfs_fs_type);
538	destroy_inodecache();
539}
540
541module_init(init_adfs_fs)
542module_exit(exit_adfs_fs)
543MODULE_LICENSE("GPL");