udf: cleanup directory offset handling
[linux-2.6.git] / fs / udf / directory.c
1 /*
2  * directory.c
3  *
4  * PURPOSE
5  *      Directory related functions
6  *
7  * COPYRIGHT
8  *      This file is distributed under the terms of the GNU General Public
9  *      License (GPL). Copies of the GPL can be obtained from:
10  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
11  *      Each contributing author retains all rights to their own work.
12  */
13
14 #include "udfdecl.h"
15 #include "udf_i.h"
16
17 #include <linux/fs.h>
18 #include <linux/string.h>
19 #include <linux/buffer_head.h>
20
21 #if 0
22 static uint8_t *udf_filead_read(struct inode *dir, uint8_t *tmpad,
23                                 uint8_t ad_size, kernel_lb_addr fe_loc,
24                                 int *pos, int *offset, struct buffer_head **bh,
25                                 int *error)
26 {
27         int loffset = *offset;
28         int block;
29         uint8_t *ad;
30         int remainder;
31
32         *error = 0;
33
34         ad = (uint8_t *)(*bh)->b_data + *offset;
35         *offset += ad_size;
36
37         if (!ad) {
38                 brelse(*bh);
39                 *error = 1;
40                 return NULL;
41         }
42
43         if (*offset == dir->i_sb->s_blocksize) {
44                 brelse(*bh);
45                 block = udf_get_lb_pblock(dir->i_sb, fe_loc, ++*pos);
46                 if (!block)
47                         return NULL;
48                 *bh = udf_tread(dir->i_sb, block);
49                 if (!*bh)
50                         return NULL;
51         } else if (*offset > dir->i_sb->s_blocksize) {
52                 ad = tmpad;
53
54                 remainder = dir->i_sb->s_blocksize - loffset;
55                 memcpy((uint8_t *)ad, (*bh)->b_data + loffset, remainder);
56
57                 brelse(*bh);
58                 block = udf_get_lb_pblock(dir->i_sb, fe_loc, ++*pos);
59                 if (!block)
60                         return NULL;
61                 (*bh) = udf_tread(dir->i_sb, block);
62                 if (!*bh)
63                         return NULL;
64
65                 memcpy((uint8_t *)ad + remainder, (*bh)->b_data,
66                         ad_size - remainder);
67                 *offset = ad_size - remainder;
68         }
69
70         return ad;
71 }
72 #endif
73
74 struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,
75                                          struct udf_fileident_bh *fibh,
76                                          struct fileIdentDesc *cfi,
77                                          struct extent_position *epos,
78                                          kernel_lb_addr *eloc, uint32_t *elen,
79                                          sector_t *offset)
80 {
81         struct fileIdentDesc *fi;
82         int i, num, block;
83         struct buffer_head *tmp, *bha[16];
84         struct udf_inode_info *iinfo = UDF_I(dir);
85
86         fibh->soffset = fibh->eoffset;
87
88         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
89                 fi = udf_get_fileident(iinfo->i_ext.i_data -
90                                        (iinfo->i_efe ?
91                                         sizeof(struct extendedFileEntry) :
92                                         sizeof(struct fileEntry)),
93                                        dir->i_sb->s_blocksize,
94                                        &(fibh->eoffset));
95                 if (!fi)
96                         return NULL;
97
98                 *nf_pos += fibh->eoffset - fibh->soffset;
99
100                 memcpy((uint8_t *)cfi, (uint8_t *)fi,
101                        sizeof(struct fileIdentDesc));
102
103                 return fi;
104         }
105
106         if (fibh->eoffset == dir->i_sb->s_blocksize) {
107                 int lextoffset = epos->offset;
108                 unsigned char blocksize_bits = dir->i_sb->s_blocksize_bits;
109
110                 if (udf_next_aext(dir, epos, eloc, elen, 1) !=
111                     (EXT_RECORDED_ALLOCATED >> 30))
112                         return NULL;
113
114                 block = udf_get_lb_pblock(dir->i_sb, *eloc, *offset);
115
116                 (*offset)++;
117
118                 if ((*offset << blocksize_bits) >= *elen)
119                         *offset = 0;
120                 else
121                         epos->offset = lextoffset;
122
123                 brelse(fibh->sbh);
124                 fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
125                 if (!fibh->sbh)
126                         return NULL;
127                 fibh->soffset = fibh->eoffset = 0;
128
129                 if (!(*offset & ((16 >> (blocksize_bits - 9)) - 1))) {
130                         i = 16 >> (blocksize_bits - 9);
131                         if (i + *offset > (*elen >> blocksize_bits))
132                                 i = (*elen >> blocksize_bits)-*offset;
133                         for (num = 0; i > 0; i--) {
134                                 block = udf_get_lb_pblock(dir->i_sb, *eloc,
135                                                           *offset + i);
136                                 tmp = udf_tgetblk(dir->i_sb, block);
137                                 if (tmp && !buffer_uptodate(tmp) &&
138                                                 !buffer_locked(tmp))
139                                         bha[num++] = tmp;
140                                 else
141                                         brelse(tmp);
142                         }
143                         if (num) {
144                                 ll_rw_block(READA, num, bha);
145                                 for (i = 0; i < num; i++)
146                                         brelse(bha[i]);
147                         }
148                 }
149         } else if (fibh->sbh != fibh->ebh) {
150                 brelse(fibh->sbh);
151                 fibh->sbh = fibh->ebh;
152         }
153
154         fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
155                                &(fibh->eoffset));
156
157         if (!fi)
158                 return NULL;
159
160         *nf_pos += fibh->eoffset - fibh->soffset;
161
162         if (fibh->eoffset <= dir->i_sb->s_blocksize) {
163                 memcpy((uint8_t *)cfi, (uint8_t *)fi,
164                        sizeof(struct fileIdentDesc));
165         } else if (fibh->eoffset > dir->i_sb->s_blocksize) {
166                 int lextoffset = epos->offset;
167
168                 if (udf_next_aext(dir, epos, eloc, elen, 1) !=
169                     (EXT_RECORDED_ALLOCATED >> 30))
170                         return NULL;
171
172                 block = udf_get_lb_pblock(dir->i_sb, *eloc, *offset);
173
174                 (*offset)++;
175
176                 if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
177                         *offset = 0;
178                 else
179                         epos->offset = lextoffset;
180
181                 fibh->soffset -= dir->i_sb->s_blocksize;
182                 fibh->eoffset -= dir->i_sb->s_blocksize;
183
184                 fibh->ebh = udf_tread(dir->i_sb, block);
185                 if (!fibh->ebh)
186                         return NULL;
187
188                 if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
189                         int fi_len;
190
191                         memcpy((uint8_t *)cfi, (uint8_t *)fi, -fibh->soffset);
192                         memcpy((uint8_t *)cfi - fibh->soffset,
193                                fibh->ebh->b_data,
194                                sizeof(struct fileIdentDesc) + fibh->soffset);
195
196                         fi_len = (sizeof(struct fileIdentDesc) +
197                                   cfi->lengthFileIdent +
198                                   le16_to_cpu(cfi->lengthOfImpUse) + 3) & ~3;
199
200                         *nf_pos += fi_len - (fibh->eoffset - fibh->soffset);
201                         fibh->eoffset = fibh->soffset + fi_len;
202                 } else {
203                         memcpy((uint8_t *)cfi, (uint8_t *)fi,
204                                sizeof(struct fileIdentDesc));
205                 }
206         }
207         return fi;
208 }
209
210 struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
211 {
212         struct fileIdentDesc *fi;
213         int lengthThisIdent;
214         uint8_t *ptr;
215         int padlen;
216
217         if ((!buffer) || (!offset)) {
218                 udf_debug("invalidparms\n, buffer=%p, offset=%p\n", buffer,
219                           offset);
220                 return NULL;
221         }
222
223         ptr = buffer;
224
225         if ((*offset > 0) && (*offset < bufsize))
226                 ptr += *offset;
227         fi = (struct fileIdentDesc *)ptr;
228         if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
229                 udf_debug("0x%x != TAG_IDENT_FID\n",
230                           le16_to_cpu(fi->descTag.tagIdent));
231                 udf_debug("offset: %u sizeof: %lu bufsize: %u\n",
232                           *offset, (unsigned long)sizeof(struct fileIdentDesc),
233                           bufsize);
234                 return NULL;
235         }
236         if ((*offset + sizeof(struct fileIdentDesc)) > bufsize)
237                 lengthThisIdent = sizeof(struct fileIdentDesc);
238         else
239                 lengthThisIdent = sizeof(struct fileIdentDesc) +
240                         fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);
241
242         /* we need to figure padding, too! */
243         padlen = lengthThisIdent % UDF_NAME_PAD;
244         if (padlen)
245                 lengthThisIdent += (UDF_NAME_PAD - padlen);
246         *offset = *offset + lengthThisIdent;
247
248         return fi;
249 }
250
251 #if 0
252 static extent_ad *udf_get_fileextent(void *buffer, int bufsize, int *offset)
253 {
254         extent_ad *ext;
255         struct fileEntry *fe;
256         uint8_t *ptr;
257
258         if ((!buffer) || (!offset)) {
259                 printk(KERN_ERR "udf: udf_get_fileextent() invalidparms\n");
260                 return NULL;
261         }
262
263         fe = (struct fileEntry *)buffer;
264
265         if (fe->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FE)) {
266                 udf_debug("0x%x != TAG_IDENT_FE\n",
267                           le16_to_cpu(fe->descTag.tagIdent));
268                 return NULL;
269         }
270
271         ptr = (uint8_t *)(fe->extendedAttr) +
272                 le32_to_cpu(fe->lengthExtendedAttr);
273
274         if ((*offset > 0) && (*offset < le32_to_cpu(fe->lengthAllocDescs)))
275                 ptr += *offset;
276
277         ext = (extent_ad *)ptr;
278
279         *offset = *offset + sizeof(extent_ad);
280         return ext;
281 }
282 #endif
283
284 short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
285                               int inc)
286 {
287         short_ad *sa;
288
289         if ((!ptr) || (!offset)) {
290                 printk(KERN_ERR "udf: udf_get_fileshortad() invalidparms\n");
291                 return NULL;
292         }
293
294         if ((*offset + sizeof(short_ad)) > maxoffset)
295                 return NULL;
296         else {
297                 sa = (short_ad *)ptr;
298                 if (sa->extLength == 0)
299                         return NULL;
300         }
301
302         if (inc)
303                 *offset += sizeof(short_ad);
304         return sa;
305 }
306
307 long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
308 {
309         long_ad *la;
310
311         if ((!ptr) || (!offset)) {
312                 printk(KERN_ERR "udf: udf_get_filelongad() invalidparms\n");
313                 return NULL;
314         }
315
316         if ((*offset + sizeof(long_ad)) > maxoffset)
317                 return NULL;
318         else {
319                 la = (long_ad *)ptr;
320                 if (la->extLength == 0)
321                         return NULL;
322         }
323
324         if (inc)
325                 *offset += sizeof(long_ad);
326         return la;
327 }