xref: /openbmc/linux/fs/hfs/super.c (revision 22246614)
1 /*
2  *  linux/fs/hfs/super.c
3  *
4  * Copyright (C) 1995-1997  Paul H. Hargrove
5  * (C) 2003 Ardis Technologies <roman@ardistech.com>
6  * This file may be distributed under the terms of the GNU General Public License.
7  *
8  * This file contains hfs_read_super(), some of the super_ops and
9  * init_hfs_fs() and exit_hfs_fs().  The remaining super_ops are in
10  * inode.c since they deal with inodes.
11  *
12  * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
13  */
14 
15 #include <linux/module.h>
16 #include <linux/blkdev.h>
17 #include <linux/mount.h>
18 #include <linux/init.h>
19 #include <linux/nls.h>
20 #include <linux/parser.h>
21 #include <linux/seq_file.h>
22 #include <linux/vfs.h>
23 
24 #include "hfs_fs.h"
25 #include "btree.h"
26 
27 static struct kmem_cache *hfs_inode_cachep;
28 
29 MODULE_LICENSE("GPL");
30 
31 /*
32  * hfs_write_super()
33  *
34  * Description:
35  *   This function is called by the VFS only. When the filesystem
36  *   is mounted r/w it updates the MDB on disk.
37  * Input Variable(s):
38  *   struct super_block *sb: Pointer to the hfs superblock
39  * Output Variable(s):
40  *   NONE
41  * Returns:
42  *   void
43  * Preconditions:
44  *   'sb' points to a "valid" (struct super_block).
45  * Postconditions:
46  *   The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb
47  *   (hfs_put_super() must set this flag!). Some MDB fields are updated
48  *   and the MDB buffer is written to disk by calling hfs_mdb_commit().
49  */
50 static void hfs_write_super(struct super_block *sb)
51 {
52 	sb->s_dirt = 0;
53 	if (sb->s_flags & MS_RDONLY)
54 		return;
55 	/* sync everything to the buffers */
56 	hfs_mdb_commit(sb);
57 }
58 
59 /*
60  * hfs_put_super()
61  *
62  * This is the put_super() entry in the super_operations structure for
63  * HFS filesystems.  The purpose is to release the resources
64  * associated with the superblock sb.
65  */
66 static void hfs_put_super(struct super_block *sb)
67 {
68 	hfs_mdb_close(sb);
69 	/* release the MDB's resources */
70 	hfs_mdb_put(sb);
71 }
72 
73 /*
74  * hfs_statfs()
75  *
76  * This is the statfs() entry in the super_operations structure for
77  * HFS filesystems.  The purpose is to return various data about the
78  * filesystem.
79  *
80  * changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
81  */
82 static int hfs_statfs(struct dentry *dentry, struct kstatfs *buf)
83 {
84 	struct super_block *sb = dentry->d_sb;
85 
86 	buf->f_type = HFS_SUPER_MAGIC;
87 	buf->f_bsize = sb->s_blocksize;
88 	buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
89 	buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
90 	buf->f_bavail = buf->f_bfree;
91 	buf->f_files = HFS_SB(sb)->fs_ablocks;
92 	buf->f_ffree = HFS_SB(sb)->free_ablocks;
93 	buf->f_namelen = HFS_NAMELEN;
94 
95 	return 0;
96 }
97 
98 static int hfs_remount(struct super_block *sb, int *flags, char *data)
99 {
100 	*flags |= MS_NODIRATIME;
101 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
102 		return 0;
103 	if (!(*flags & MS_RDONLY)) {
104 		if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
105 			printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
106 			       "running fsck.hfs is recommended.  leaving read-only.\n");
107 			sb->s_flags |= MS_RDONLY;
108 			*flags |= MS_RDONLY;
109 		} else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
110 			printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
111 			sb->s_flags |= MS_RDONLY;
112 			*flags |= MS_RDONLY;
113 		}
114 	}
115 	return 0;
116 }
117 
118 static int hfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
119 {
120 	struct hfs_sb_info *sbi = HFS_SB(mnt->mnt_sb);
121 
122 	if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
123 		seq_printf(seq, ",creator=%.4s", (char *)&sbi->s_creator);
124 	if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
125 		seq_printf(seq, ",type=%.4s", (char *)&sbi->s_type);
126 	seq_printf(seq, ",uid=%u,gid=%u", sbi->s_uid, sbi->s_gid);
127 	if (sbi->s_file_umask != 0133)
128 		seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
129 	if (sbi->s_dir_umask != 0022)
130 		seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
131 	if (sbi->part >= 0)
132 		seq_printf(seq, ",part=%u", sbi->part);
133 	if (sbi->session >= 0)
134 		seq_printf(seq, ",session=%u", sbi->session);
135 	if (sbi->nls_disk)
136 		seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
137 	if (sbi->nls_io)
138 		seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
139 	if (sbi->s_quiet)
140 		seq_printf(seq, ",quiet");
141 	return 0;
142 }
143 
144 static struct inode *hfs_alloc_inode(struct super_block *sb)
145 {
146 	struct hfs_inode_info *i;
147 
148 	i = kmem_cache_alloc(hfs_inode_cachep, GFP_KERNEL);
149 	return i ? &i->vfs_inode : NULL;
150 }
151 
152 static void hfs_destroy_inode(struct inode *inode)
153 {
154 	kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
155 }
156 
157 static const struct super_operations hfs_super_operations = {
158 	.alloc_inode	= hfs_alloc_inode,
159 	.destroy_inode	= hfs_destroy_inode,
160 	.write_inode	= hfs_write_inode,
161 	.clear_inode	= hfs_clear_inode,
162 	.put_super	= hfs_put_super,
163 	.write_super	= hfs_write_super,
164 	.statfs		= hfs_statfs,
165 	.remount_fs     = hfs_remount,
166 	.show_options	= hfs_show_options,
167 };
168 
169 enum {
170 	opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
171 	opt_part, opt_session, opt_type, opt_creator, opt_quiet,
172 	opt_codepage, opt_iocharset,
173 	opt_err
174 };
175 
176 static match_table_t tokens = {
177 	{ opt_uid, "uid=%u" },
178 	{ opt_gid, "gid=%u" },
179 	{ opt_umask, "umask=%o" },
180 	{ opt_file_umask, "file_umask=%o" },
181 	{ opt_dir_umask, "dir_umask=%o" },
182 	{ opt_part, "part=%u" },
183 	{ opt_session, "session=%u" },
184 	{ opt_type, "type=%s" },
185 	{ opt_creator, "creator=%s" },
186 	{ opt_quiet, "quiet" },
187 	{ opt_codepage, "codepage=%s" },
188 	{ opt_iocharset, "iocharset=%s" },
189 	{ opt_err, NULL }
190 };
191 
192 static inline int match_fourchar(substring_t *arg, u32 *result)
193 {
194 	if (arg->to - arg->from != 4)
195 		return -EINVAL;
196 	memcpy(result, arg->from, 4);
197 	return 0;
198 }
199 
200 /*
201  * parse_options()
202  *
203  * adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
204  * This function is called by hfs_read_super() to parse the mount options.
205  */
206 static int parse_options(char *options, struct hfs_sb_info *hsb)
207 {
208 	char *p;
209 	substring_t args[MAX_OPT_ARGS];
210 	int tmp, token;
211 
212 	/* initialize the sb with defaults */
213 	hsb->s_uid = current->uid;
214 	hsb->s_gid = current->gid;
215 	hsb->s_file_umask = 0133;
216 	hsb->s_dir_umask = 0022;
217 	hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f);	/* == '????' */
218 	hsb->s_quiet = 0;
219 	hsb->part = -1;
220 	hsb->session = -1;
221 
222 	if (!options)
223 		return 1;
224 
225 	while ((p = strsep(&options, ",")) != NULL) {
226 		if (!*p)
227 			continue;
228 
229 		token = match_token(p, tokens, args);
230 		switch (token) {
231 		case opt_uid:
232 			if (match_int(&args[0], &tmp)) {
233 				printk(KERN_ERR "hfs: uid requires an argument\n");
234 				return 0;
235 			}
236 			hsb->s_uid = (uid_t)tmp;
237 			break;
238 		case opt_gid:
239 			if (match_int(&args[0], &tmp)) {
240 				printk(KERN_ERR "hfs: gid requires an argument\n");
241 				return 0;
242 			}
243 			hsb->s_gid = (gid_t)tmp;
244 			break;
245 		case opt_umask:
246 			if (match_octal(&args[0], &tmp)) {
247 				printk(KERN_ERR "hfs: umask requires a value\n");
248 				return 0;
249 			}
250 			hsb->s_file_umask = (umode_t)tmp;
251 			hsb->s_dir_umask = (umode_t)tmp;
252 			break;
253 		case opt_file_umask:
254 			if (match_octal(&args[0], &tmp)) {
255 				printk(KERN_ERR "hfs: file_umask requires a value\n");
256 				return 0;
257 			}
258 			hsb->s_file_umask = (umode_t)tmp;
259 			break;
260 		case opt_dir_umask:
261 			if (match_octal(&args[0], &tmp)) {
262 				printk(KERN_ERR "hfs: dir_umask requires a value\n");
263 				return 0;
264 			}
265 			hsb->s_dir_umask = (umode_t)tmp;
266 			break;
267 		case opt_part:
268 			if (match_int(&args[0], &hsb->part)) {
269 				printk(KERN_ERR "hfs: part requires an argument\n");
270 				return 0;
271 			}
272 			break;
273 		case opt_session:
274 			if (match_int(&args[0], &hsb->session)) {
275 				printk(KERN_ERR "hfs: session requires an argument\n");
276 				return 0;
277 			}
278 			break;
279 		case opt_type:
280 			if (match_fourchar(&args[0], &hsb->s_type)) {
281 				printk(KERN_ERR "hfs: type requires a 4 character value\n");
282 				return 0;
283 			}
284 			break;
285 		case opt_creator:
286 			if (match_fourchar(&args[0], &hsb->s_creator)) {
287 				printk(KERN_ERR "hfs: creator requires a 4 character value\n");
288 				return 0;
289 			}
290 			break;
291 		case opt_quiet:
292 			hsb->s_quiet = 1;
293 			break;
294 		case opt_codepage:
295 			if (hsb->nls_disk) {
296 				printk(KERN_ERR "hfs: unable to change codepage\n");
297 				return 0;
298 			}
299 			p = match_strdup(&args[0]);
300 			if (p)
301 				hsb->nls_disk = load_nls(p);
302 			if (!hsb->nls_disk) {
303 				printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
304 				kfree(p);
305 				return 0;
306 			}
307 			kfree(p);
308 			break;
309 		case opt_iocharset:
310 			if (hsb->nls_io) {
311 				printk(KERN_ERR "hfs: unable to change iocharset\n");
312 				return 0;
313 			}
314 			p = match_strdup(&args[0]);
315 			if (p)
316 				hsb->nls_io = load_nls(p);
317 			if (!hsb->nls_io) {
318 				printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
319 				kfree(p);
320 				return 0;
321 			}
322 			kfree(p);
323 			break;
324 		default:
325 			return 0;
326 		}
327 	}
328 
329 	if (hsb->nls_disk && !hsb->nls_io) {
330 		hsb->nls_io = load_nls_default();
331 		if (!hsb->nls_io) {
332 			printk(KERN_ERR "hfs: unable to load default iocharset\n");
333 			return 0;
334 		}
335 	}
336 	hsb->s_dir_umask &= 0777;
337 	hsb->s_file_umask &= 0577;
338 
339 	return 1;
340 }
341 
342 /*
343  * hfs_read_super()
344  *
345  * This is the function that is responsible for mounting an HFS
346  * filesystem.	It performs all the tasks necessary to get enough data
347  * from the disk to read the root inode.  This includes parsing the
348  * mount options, dealing with Macintosh partitions, reading the
349  * superblock and the allocation bitmap blocks, calling
350  * hfs_btree_init() to get the necessary data about the extents and
351  * catalog B-trees and, finally, reading the root inode into memory.
352  */
353 static int hfs_fill_super(struct super_block *sb, void *data, int silent)
354 {
355 	struct hfs_sb_info *sbi;
356 	struct hfs_find_data fd;
357 	hfs_cat_rec rec;
358 	struct inode *root_inode;
359 	int res;
360 
361 	sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
362 	if (!sbi)
363 		return -ENOMEM;
364 	sb->s_fs_info = sbi;
365 	INIT_HLIST_HEAD(&sbi->rsrc_inodes);
366 
367 	res = -EINVAL;
368 	if (!parse_options((char *)data, sbi)) {
369 		printk(KERN_ERR "hfs: unable to parse mount options.\n");
370 		goto bail;
371 	}
372 
373 	sb->s_op = &hfs_super_operations;
374 	sb->s_flags |= MS_NODIRATIME;
375 	init_MUTEX(&sbi->bitmap_lock);
376 
377 	res = hfs_mdb_get(sb);
378 	if (res) {
379 		if (!silent)
380 			printk(KERN_WARNING "hfs: can't find a HFS filesystem on dev %s.\n",
381 				hfs_mdb_name(sb));
382 		res = -EINVAL;
383 		goto bail;
384 	}
385 
386 	/* try to get the root inode */
387 	hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
388 	res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
389 	if (!res)
390 		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
391 	if (res) {
392 		hfs_find_exit(&fd);
393 		goto bail_no_root;
394 	}
395 	res = -EINVAL;
396 	root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
397 	hfs_find_exit(&fd);
398 	if (!root_inode)
399 		goto bail_no_root;
400 
401 	res = -ENOMEM;
402 	sb->s_root = d_alloc_root(root_inode);
403 	if (!sb->s_root)
404 		goto bail_iput;
405 
406 	sb->s_root->d_op = &hfs_dentry_operations;
407 
408 	/* everything's okay */
409 	return 0;
410 
411 bail_iput:
412 	iput(root_inode);
413 bail_no_root:
414 	printk(KERN_ERR "hfs: get root inode failed.\n");
415 bail:
416 	hfs_mdb_put(sb);
417 	return res;
418 }
419 
420 static int hfs_get_sb(struct file_system_type *fs_type,
421 		      int flags, const char *dev_name, void *data,
422 		      struct vfsmount *mnt)
423 {
424 	return get_sb_bdev(fs_type, flags, dev_name, data, hfs_fill_super, mnt);
425 }
426 
427 static struct file_system_type hfs_fs_type = {
428 	.owner		= THIS_MODULE,
429 	.name		= "hfs",
430 	.get_sb		= hfs_get_sb,
431 	.kill_sb	= kill_block_super,
432 	.fs_flags	= FS_REQUIRES_DEV,
433 };
434 
435 static void hfs_init_once(struct kmem_cache *cachep, void *p)
436 {
437 	struct hfs_inode_info *i = p;
438 
439 	inode_init_once(&i->vfs_inode);
440 }
441 
442 static int __init init_hfs_fs(void)
443 {
444 	int err;
445 
446 	hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
447 		sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
448 		hfs_init_once);
449 	if (!hfs_inode_cachep)
450 		return -ENOMEM;
451 	err = register_filesystem(&hfs_fs_type);
452 	if (err)
453 		kmem_cache_destroy(hfs_inode_cachep);
454 	return err;
455 }
456 
457 static void __exit exit_hfs_fs(void)
458 {
459 	unregister_filesystem(&hfs_fs_type);
460 	kmem_cache_destroy(hfs_inode_cachep);
461 }
462 
463 module_init(init_hfs_fs)
464 module_exit(exit_hfs_fs)
465