[PATCH] hfs_fill_super returns success even if no root inode
[linux-2.6.git] / fs / hfs / super.c
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_module() and cleanup_module().  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 kmem_cache_t *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, SLAB_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 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                         hsb->nls_disk = load_nls(p);
301                         if (!hsb->nls_disk) {
302                                 printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
303                                 kfree(p);
304                                 return 0;
305                         }
306                         kfree(p);
307                         break;
308                 case opt_iocharset:
309                         if (hsb->nls_io) {
310                                 printk(KERN_ERR "hfs: unable to change iocharset\n");
311                                 return 0;
312                         }
313                         p = match_strdup(&args[0]);
314                         hsb->nls_io = load_nls(p);
315                         if (!hsb->nls_io) {
316                                 printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
317                                 kfree(p);
318                                 return 0;
319                         }
320                         kfree(p);
321                         break;
322                 default:
323                         return 0;
324                 }
325         }
326
327         if (hsb->nls_disk && !hsb->nls_io) {
328                 hsb->nls_io = load_nls_default();
329                 if (!hsb->nls_io) {
330                         printk(KERN_ERR "hfs: unable to load default iocharset\n");
331                         return 0;
332                 }
333         }
334         hsb->s_dir_umask &= 0777;
335         hsb->s_file_umask &= 0577;
336
337         return 1;
338 }
339
340 /*
341  * hfs_read_super()
342  *
343  * This is the function that is responsible for mounting an HFS
344  * filesystem.  It performs all the tasks necessary to get enough data
345  * from the disk to read the root inode.  This includes parsing the
346  * mount options, dealing with Macintosh partitions, reading the
347  * superblock and the allocation bitmap blocks, calling
348  * hfs_btree_init() to get the necessary data about the extents and
349  * catalog B-trees and, finally, reading the root inode into memory.
350  */
351 static int hfs_fill_super(struct super_block *sb, void *data, int silent)
352 {
353         struct hfs_sb_info *sbi;
354         struct hfs_find_data fd;
355         hfs_cat_rec rec;
356         struct inode *root_inode;
357         int res;
358
359         sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
360         if (!sbi)
361                 return -ENOMEM;
362         sb->s_fs_info = sbi;
363         INIT_HLIST_HEAD(&sbi->rsrc_inodes);
364
365         res = -EINVAL;
366         if (!parse_options((char *)data, sbi)) {
367                 printk(KERN_ERR "hfs: unable to parse mount options.\n");
368                 goto bail;
369         }
370
371         sb->s_op = &hfs_super_operations;
372         sb->s_flags |= MS_NODIRATIME;
373         init_MUTEX(&sbi->bitmap_lock);
374
375         res = hfs_mdb_get(sb);
376         if (res) {
377                 if (!silent)
378                         printk(KERN_WARNING "hfs: can't find a HFS filesystem on dev %s.\n",
379                                 hfs_mdb_name(sb));
380                 res = -EINVAL;
381                 goto bail;
382         }
383
384         /* try to get the root inode */
385         hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
386         res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
387         if (!res)
388                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
389         if (res) {
390                 hfs_find_exit(&fd);
391                 goto bail_no_root;
392         }
393         res = -EINVAL;
394         root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
395         hfs_find_exit(&fd);
396         if (!root_inode)
397                 goto bail_no_root;
398
399         res = -ENOMEM;
400         sb->s_root = d_alloc_root(root_inode);
401         if (!sb->s_root)
402                 goto bail_iput;
403
404         sb->s_root->d_op = &hfs_dentry_operations;
405
406         /* everything's okay */
407         return 0;
408
409 bail_iput:
410         iput(root_inode);
411 bail_no_root:
412         printk(KERN_ERR "hfs: get root inode failed.\n");
413 bail:
414         hfs_mdb_put(sb);
415         return res;
416 }
417
418 static int hfs_get_sb(struct file_system_type *fs_type,
419                       int flags, const char *dev_name, void *data,
420                       struct vfsmount *mnt)
421 {
422         return get_sb_bdev(fs_type, flags, dev_name, data, hfs_fill_super, mnt);
423 }
424
425 static struct file_system_type hfs_fs_type = {
426         .owner          = THIS_MODULE,
427         .name           = "hfs",
428         .get_sb         = hfs_get_sb,
429         .kill_sb        = kill_block_super,
430         .fs_flags       = FS_REQUIRES_DEV,
431 };
432
433 static void hfs_init_once(void *p, kmem_cache_t *cachep, unsigned long flags)
434 {
435         struct hfs_inode_info *i = p;
436
437         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR)
438                 inode_init_once(&i->vfs_inode);
439 }
440
441 static int __init init_hfs_fs(void)
442 {
443         int err;
444
445         hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
446                 sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
447                 hfs_init_once, NULL);
448         if (!hfs_inode_cachep)
449                 return -ENOMEM;
450         err = register_filesystem(&hfs_fs_type);
451         if (err)
452                 kmem_cache_destroy(hfs_inode_cachep);
453         return err;
454 }
455
456 static void __exit exit_hfs_fs(void)
457 {
458         unregister_filesystem(&hfs_fs_type);
459         kmem_cache_destroy(hfs_inode_cachep);
460 }
461
462 module_init(init_hfs_fs)
463 module_exit(exit_hfs_fs)