Push BKL down into ->remount_fs()
[linux-2.6.git] / fs / hpfs / map.c
1 /*
2  *  linux/fs/hpfs/map.c
3  *
4  *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
5  *
6  *  mapping structures to memory with some minimal checks
7  */
8
9 #include "hpfs_fn.h"
10
11 unsigned *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
12 {
13         return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
14 }
15
16 unsigned int *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
17                          struct quad_buffer_head *qbh, char *id)
18 {
19         secno sec;
20         if (hpfs_sb(s)->sb_chk) if (bmp_block * 16384 > hpfs_sb(s)->sb_fs_size) {
21                 hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
22                 return NULL;
23         }
24         sec = hpfs_sb(s)->sb_bmp_dir[bmp_block];
25         if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
26                 hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
27                 return NULL;
28         }
29         return hpfs_map_4sectors(s, sec, qbh, 4);
30 }
31
32 /*
33  * Load first code page into kernel memory, return pointer to 256-byte array,
34  * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
35  * lowercasing table
36  */
37
38 char *hpfs_load_code_page(struct super_block *s, secno cps)
39 {
40         struct buffer_head *bh;
41         secno cpds;
42         unsigned cpi;
43         unsigned char *ptr;
44         unsigned char *cp_table;
45         int i;
46         struct code_page_data *cpd;
47         struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
48         if (!cp) return NULL;
49         if (cp->magic != CP_DIR_MAGIC) {
50                 printk("HPFS: Code page directory magic doesn't match (magic = %08x)\n", cp->magic);
51                 brelse(bh);
52                 return NULL;
53         }
54         if (!cp->n_code_pages) {
55                 printk("HPFS: n_code_pages == 0\n");
56                 brelse(bh);
57                 return NULL;
58         }
59         cpds = cp->array[0].code_page_data;
60         cpi = cp->array[0].index;
61         brelse(bh);
62
63         if (cpi >= 3) {
64                 printk("HPFS: Code page index out of array\n");
65                 return NULL;
66         }
67         
68         if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
69         if ((unsigned)cpd->offs[cpi] > 0x178) {
70                 printk("HPFS: Code page index out of sector\n");
71                 brelse(bh);
72                 return NULL;
73         }
74         ptr = (char *)cpd + cpd->offs[cpi] + 6;
75         if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
76                 printk("HPFS: out of memory for code page table\n");
77                 brelse(bh);
78                 return NULL;
79         }
80         memcpy(cp_table, ptr, 128);
81         brelse(bh);
82
83         /* Try to build lowercasing table from uppercasing one */
84
85         for (i=128; i<256; i++) cp_table[i]=i;
86         for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
87                 cp_table[cp_table[i-128]] = i;
88         
89         return cp_table;
90 }
91
92 secno *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
93 {
94         struct buffer_head *bh;
95         int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
96         int i;
97         secno *b;
98         if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
99                 printk("HPFS: can't allocate memory for bitmap directory\n");
100                 return NULL;
101         }       
102         for (i=0;i<n;i++) {
103                 secno *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
104                 if (!d) {
105                         kfree(b);
106                         return NULL;
107                 }
108                 memcpy((char *)b + 512 * i, d, 512);
109                 brelse(bh);
110         }
111         return b;
112 }
113
114 /*
115  * Load fnode to memory
116  */
117
118 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
119 {
120         struct fnode *fnode;
121         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
122                 return NULL;
123         }
124         if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
125                 if (hpfs_sb(s)->sb_chk) {
126                         struct extended_attribute *ea;
127                         struct extended_attribute *ea_end;
128                         if (fnode->magic != FNODE_MAGIC) {
129                                 hpfs_error(s, "bad magic on fnode %08lx",
130                                         (unsigned long)ino);
131                                 goto bail;
132                         }
133                         if (!fnode->dirflag) {
134                                 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
135                                     (fnode->btree.internal ? 12 : 8)) {
136                                         hpfs_error(s,
137                                            "bad number of nodes in fnode %08lx",
138                                             (unsigned long)ino);
139                                         goto bail;
140                                 }
141                                 if (fnode->btree.first_free !=
142                                     8 + fnode->btree.n_used_nodes * (fnode->btree.internal ? 8 : 12)) {
143                                         hpfs_error(s,
144                                             "bad first_free pointer in fnode %08lx",
145                                             (unsigned long)ino);
146                                         goto bail;
147                                 }
148                         }
149                         if (fnode->ea_size_s && ((signed int)fnode->ea_offs < 0xc4 ||
150                            (signed int)fnode->ea_offs + fnode->acl_size_s + fnode->ea_size_s > 0x200)) {
151                                 hpfs_error(s,
152                                         "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
153                                         (unsigned long)ino,
154                                         fnode->ea_offs, fnode->ea_size_s);
155                                 goto bail;
156                         }
157                         ea = fnode_ea(fnode);
158                         ea_end = fnode_end_ea(fnode);
159                         while (ea != ea_end) {
160                                 if (ea > ea_end) {
161                                         hpfs_error(s, "bad EA in fnode %08lx",
162                                                 (unsigned long)ino);
163                                         goto bail;
164                                 }
165                                 ea = next_ea(ea);
166                         }
167                 }
168         }
169         return fnode;
170         bail:
171         brelse(*bhp);
172         return NULL;
173 }
174
175 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
176 {
177         struct anode *anode;
178         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
179         if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
180                 if (hpfs_sb(s)->sb_chk) {
181                         if (anode->magic != ANODE_MAGIC || anode->self != ano) {
182                                 hpfs_error(s, "bad magic on anode %08x", ano);
183                                 goto bail;
184                         }
185                         if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
186                             (anode->btree.internal ? 60 : 40)) {
187                                 hpfs_error(s, "bad number of nodes in anode %08x", ano);
188                                 goto bail;
189                         }
190                         if (anode->btree.first_free !=
191                             8 + anode->btree.n_used_nodes * (anode->btree.internal ? 8 : 12)) {
192                                 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
193                                 goto bail;
194                         }
195                 }
196         return anode;
197         bail:
198         brelse(*bhp);
199         return NULL;
200 }
201
202 /*
203  * Load dnode to memory and do some checks
204  */
205
206 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
207                              struct quad_buffer_head *qbh)
208 {
209         struct dnode *dnode;
210         if (hpfs_sb(s)->sb_chk) {
211                 if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
212                 if (secno & 3) {
213                         hpfs_error(s, "dnode %08x not byte-aligned", secno);
214                         return NULL;
215                 }       
216         }
217         if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
218                 if (hpfs_sb(s)->sb_chk) {
219                         unsigned p, pp = 0;
220                         unsigned char *d = (char *)dnode;
221                         int b = 0;
222                         if (dnode->magic != DNODE_MAGIC) {
223                                 hpfs_error(s, "bad magic on dnode %08x", secno);
224                                 goto bail;
225                         }
226                         if (dnode->self != secno)
227                                 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, dnode->self);
228                         /* Check dirents - bad dirents would cause infinite
229                            loops or shooting to memory */
230                         if (dnode->first_free > 2048/* || dnode->first_free < 84*/) {
231                                 hpfs_error(s, "dnode %08x has first_free == %08x", secno, dnode->first_free);
232                                 goto bail;
233                         }
234                         for (p = 20; p < dnode->first_free; p += d[p] + (d[p+1] << 8)) {
235                                 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
236                                 if (de->length > 292 || (de->length < 32) || (de->length & 3) || p + de->length > 2048) {
237                                         hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
238                                         goto bail;
239                                 }
240                                 if (((31 + de->namelen + de->down*4 + 3) & ~3) != de->length) {
241                                         if (((31 + de->namelen + de->down*4 + 3) & ~3) < de->length && s->s_flags & MS_RDONLY) goto ok;
242                                         hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
243                                         goto bail;
244                                 }
245                                 ok:
246                                 if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
247                                 if (de->down) if (de_down_pointer(de) < 0x10) {
248                                         hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
249                                         goto bail;
250                                 }
251                                 pp = p;
252                                 
253                         }
254                         if (p != dnode->first_free) {
255                                 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
256                                 goto bail;
257                         }
258                         if (d[pp + 30] != 1 || d[pp + 31] != 255) {
259                                 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
260                                 goto bail;
261                         }
262                         if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
263                 }
264         return dnode;
265         bail:
266         hpfs_brelse4(qbh);
267         return NULL;
268 }
269
270 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
271 {
272         struct buffer_head *bh;
273         struct fnode *fnode;
274         dnode_secno dno;
275
276         fnode = hpfs_map_fnode(s, ino, &bh);
277         if (!fnode)
278                 return 0;
279
280         dno = fnode->u.external[0].disk_secno;
281         brelse(bh);
282         return dno;
283 }