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Fix i_mutex vs. readdir handling in nfsd
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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         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
86
87         buf->f_type = HFS_SUPER_MAGIC;
88         buf->f_bsize = sb->s_blocksize;
89         buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
90         buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
91         buf->f_bavail = buf->f_bfree;
92         buf->f_files = HFS_SB(sb)->fs_ablocks;
93         buf->f_ffree = HFS_SB(sb)->free_ablocks;
94         buf->f_fsid.val[0] = (u32)id;
95         buf->f_fsid.val[1] = (u32)(id >> 32);
96         buf->f_namelen = HFS_NAMELEN;
97
98         return 0;
99 }
100
101 static int hfs_remount(struct super_block *sb, int *flags, char *data)
102 {
103         *flags |= MS_NODIRATIME;
104         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
105                 return 0;
106         if (!(*flags & MS_RDONLY)) {
107                 if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
108                         printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
109                                "running fsck.hfs is recommended.  leaving read-only.\n");
110                         sb->s_flags |= MS_RDONLY;
111                         *flags |= MS_RDONLY;
112                 } else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
113                         printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
114                         sb->s_flags |= MS_RDONLY;
115                         *flags |= MS_RDONLY;
116                 }
117         }
118         return 0;
119 }
120
121 static int hfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
122 {
123         struct hfs_sb_info *sbi = HFS_SB(mnt->mnt_sb);
124
125         if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
126                 seq_printf(seq, ",creator=%.4s", (char *)&sbi->s_creator);
127         if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
128                 seq_printf(seq, ",type=%.4s", (char *)&sbi->s_type);
129         seq_printf(seq, ",uid=%u,gid=%u", sbi->s_uid, sbi->s_gid);
130         if (sbi->s_file_umask != 0133)
131                 seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
132         if (sbi->s_dir_umask != 0022)
133                 seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
134         if (sbi->part >= 0)
135                 seq_printf(seq, ",part=%u", sbi->part);
136         if (sbi->session >= 0)
137                 seq_printf(seq, ",session=%u", sbi->session);
138         if (sbi->nls_disk)
139                 seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
140         if (sbi->nls_io)
141                 seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
142         if (sbi->s_quiet)
143                 seq_printf(seq, ",quiet");
144         return 0;
145 }
146
147 static struct inode *hfs_alloc_inode(struct super_block *sb)
148 {
149         struct hfs_inode_info *i;
150
151         i = kmem_cache_alloc(hfs_inode_cachep, GFP_KERNEL);
152         return i ? &i->vfs_inode : NULL;
153 }
154
155 static void hfs_destroy_inode(struct inode *inode)
156 {
157         kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
158 }
159
160 static const struct super_operations hfs_super_operations = {
161         .alloc_inode    = hfs_alloc_inode,
162         .destroy_inode  = hfs_destroy_inode,
163         .write_inode    = hfs_write_inode,
164         .clear_inode    = hfs_clear_inode,
165         .put_super      = hfs_put_super,
166         .write_super    = hfs_write_super,
167         .statfs         = hfs_statfs,
168         .remount_fs     = hfs_remount,
169         .show_options   = hfs_show_options,
170 };
171
172 enum {
173         opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
174         opt_part, opt_session, opt_type, opt_creator, opt_quiet,
175         opt_codepage, opt_iocharset,
176         opt_err
177 };
178
179 static const match_table_t tokens = {
180         { opt_uid, "uid=%u" },
181         { opt_gid, "gid=%u" },
182         { opt_umask, "umask=%o" },
183         { opt_file_umask, "file_umask=%o" },
184         { opt_dir_umask, "dir_umask=%o" },
185         { opt_part, "part=%u" },
186         { opt_session, "session=%u" },
187         { opt_type, "type=%s" },
188         { opt_creator, "creator=%s" },
189         { opt_quiet, "quiet" },
190         { opt_codepage, "codepage=%s" },
191         { opt_iocharset, "iocharset=%s" },
192         { opt_err, NULL }
193 };
194
195 static inline int match_fourchar(substring_t *arg, u32 *result)
196 {
197         if (arg->to - arg->from != 4)
198                 return -EINVAL;
199         memcpy(result, arg->from, 4);
200         return 0;
201 }
202
203 /*
204  * parse_options()
205  *
206  * adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
207  * This function is called by hfs_read_super() to parse the mount options.
208  */
209 static int parse_options(char *options, struct hfs_sb_info *hsb)
210 {
211         char *p;
212         substring_t args[MAX_OPT_ARGS];
213         int tmp, token;
214
215         /* initialize the sb with defaults */
216         hsb->s_uid = current_uid();
217         hsb->s_gid = current_gid();
218         hsb->s_file_umask = 0133;
219         hsb->s_dir_umask = 0022;
220         hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
221         hsb->s_quiet = 0;
222         hsb->part = -1;
223         hsb->session = -1;
224
225         if (!options)
226                 return 1;
227
228         while ((p = strsep(&options, ",")) != NULL) {
229                 if (!*p)
230                         continue;
231
232                 token = match_token(p, tokens, args);
233                 switch (token) {
234                 case opt_uid:
235                         if (match_int(&args[0], &tmp)) {
236                                 printk(KERN_ERR "hfs: uid requires an argument\n");
237                                 return 0;
238                         }
239                         hsb->s_uid = (uid_t)tmp;
240                         break;
241                 case opt_gid:
242                         if (match_int(&args[0], &tmp)) {
243                                 printk(KERN_ERR "hfs: gid requires an argument\n");
244                                 return 0;
245                         }
246                         hsb->s_gid = (gid_t)tmp;
247                         break;
248                 case opt_umask:
249                         if (match_octal(&args[0], &tmp)) {
250                                 printk(KERN_ERR "hfs: umask requires a value\n");
251                                 return 0;
252                         }
253                         hsb->s_file_umask = (umode_t)tmp;
254                         hsb->s_dir_umask = (umode_t)tmp;
255                         break;
256                 case opt_file_umask:
257                         if (match_octal(&args[0], &tmp)) {
258                                 printk(KERN_ERR "hfs: file_umask requires a value\n");
259                                 return 0;
260                         }
261                         hsb->s_file_umask = (umode_t)tmp;
262                         break;
263                 case opt_dir_umask:
264                         if (match_octal(&args[0], &tmp)) {
265                                 printk(KERN_ERR "hfs: dir_umask requires a value\n");
266                                 return 0;
267                         }
268                         hsb->s_dir_umask = (umode_t)tmp;
269                         break;
270                 case opt_part:
271                         if (match_int(&args[0], &hsb->part)) {
272                                 printk(KERN_ERR "hfs: part requires an argument\n");
273                                 return 0;
274                         }
275                         break;
276                 case opt_session:
277                         if (match_int(&args[0], &hsb->session)) {
278                                 printk(KERN_ERR "hfs: session requires an argument\n");
279                                 return 0;
280                         }
281                         break;
282                 case opt_type:
283                         if (match_fourchar(&args[0], &hsb->s_type)) {
284                                 printk(KERN_ERR "hfs: type requires a 4 character value\n");
285                                 return 0;
286                         }
287                         break;
288                 case opt_creator:
289                         if (match_fourchar(&args[0], &hsb->s_creator)) {
290                                 printk(KERN_ERR "hfs: creator requires a 4 character value\n");
291                                 return 0;
292                         }
293                         break;
294                 case opt_quiet:
295                         hsb->s_quiet = 1;
296                         break;
297                 case opt_codepage:
298                         if (hsb->nls_disk) {
299                                 printk(KERN_ERR "hfs: unable to change codepage\n");
300                                 return 0;
301                         }
302                         p = match_strdup(&args[0]);
303                         if (p)
304                                 hsb->nls_disk = load_nls(p);
305                         if (!hsb->nls_disk) {
306                                 printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
307                                 kfree(p);
308                                 return 0;
309                         }
310                         kfree(p);
311                         break;
312                 case opt_iocharset:
313                         if (hsb->nls_io) {
314                                 printk(KERN_ERR "hfs: unable to change iocharset\n");
315                                 return 0;
316                         }
317                         p = match_strdup(&args[0]);
318                         if (p)
319                                 hsb->nls_io = load_nls(p);
320                         if (!hsb->nls_io) {
321                                 printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
322                                 kfree(p);
323                                 return 0;
324                         }
325                         kfree(p);
326                         break;
327                 default:
328                         return 0;
329                 }
330         }
331
332         if (hsb->nls_disk && !hsb->nls_io) {
333                 hsb->nls_io = load_nls_default();
334                 if (!hsb->nls_io) {
335                         printk(KERN_ERR "hfs: unable to load default iocharset\n");
336                         return 0;
337                 }
338         }
339         hsb->s_dir_umask &= 0777;
340         hsb->s_file_umask &= 0577;
341
342         return 1;
343 }
344
345 /*
346  * hfs_read_super()
347  *
348  * This is the function that is responsible for mounting an HFS
349  * filesystem.  It performs all the tasks necessary to get enough data
350  * from the disk to read the root inode.  This includes parsing the
351  * mount options, dealing with Macintosh partitions, reading the
352  * superblock and the allocation bitmap blocks, calling
353  * hfs_btree_init() to get the necessary data about the extents and
354  * catalog B-trees and, finally, reading the root inode into memory.
355  */
356 static int hfs_fill_super(struct super_block *sb, void *data, int silent)
357 {
358         struct hfs_sb_info *sbi;
359         struct hfs_find_data fd;
360         hfs_cat_rec rec;
361         struct inode *root_inode;
362         int res;
363
364         sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
365         if (!sbi)
366                 return -ENOMEM;
367         sb->s_fs_info = sbi;
368         INIT_HLIST_HEAD(&sbi->rsrc_inodes);
369
370         res = -EINVAL;
371         if (!parse_options((char *)data, sbi)) {
372                 printk(KERN_ERR "hfs: unable to parse mount options.\n");
373                 goto bail;
374         }
375
376         sb->s_op = &hfs_super_operations;
377         sb->s_flags |= MS_NODIRATIME;
378         mutex_init(&sbi->bitmap_lock);
379
380         res = hfs_mdb_get(sb);
381         if (res) {
382                 if (!silent)
383                         printk(KERN_WARNING "hfs: can't find a HFS filesystem on dev %s.\n",
384                                 hfs_mdb_name(sb));
385                 res = -EINVAL;
386                 goto bail;
387         }
388
389         /* try to get the root inode */
390         hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
391         res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
392         if (!res)
393                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
394         if (res) {
395                 hfs_find_exit(&fd);
396                 goto bail_no_root;
397         }
398         res = -EINVAL;
399         root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
400         hfs_find_exit(&fd);
401         if (!root_inode)
402                 goto bail_no_root;
403
404         res = -ENOMEM;
405         sb->s_root = d_alloc_root(root_inode);
406         if (!sb->s_root)
407                 goto bail_iput;
408
409         sb->s_root->d_op = &hfs_dentry_operations;
410
411         /* everything's okay */
412         return 0;
413
414 bail_iput:
415         iput(root_inode);
416 bail_no_root:
417         printk(KERN_ERR "hfs: get root inode failed.\n");
418 bail:
419         hfs_mdb_put(sb);
420         return res;
421 }
422
423 static int hfs_get_sb(struct file_system_type *fs_type,
424                       int flags, const char *dev_name, void *data,
425                       struct vfsmount *mnt)
426 {
427         return get_sb_bdev(fs_type, flags, dev_name, data, hfs_fill_super, mnt);
428 }
429
430 static struct file_system_type hfs_fs_type = {
431         .owner          = THIS_MODULE,
432         .name           = "hfs",
433         .get_sb         = hfs_get_sb,
434         .kill_sb        = kill_block_super,
435         .fs_flags       = FS_REQUIRES_DEV,
436 };
437
438 static void hfs_init_once(void *p)
439 {
440         struct hfs_inode_info *i = p;
441
442         inode_init_once(&i->vfs_inode);
443 }
444
445 static int __init init_hfs_fs(void)
446 {
447         int err;
448
449         hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
450                 sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
451                 hfs_init_once);
452         if (!hfs_inode_cachep)
453                 return -ENOMEM;
454         err = register_filesystem(&hfs_fs_type);
455         if (err)
456                 kmem_cache_destroy(hfs_inode_cachep);
457         return err;
458 }
459
460 static void __exit exit_hfs_fs(void)
461 {
462         unregister_filesystem(&hfs_fs_type);
463         kmem_cache_destroy(hfs_inode_cachep);
464 }
465
466 module_init(init_hfs_fs)
467 module_exit(exit_hfs_fs)