fat: Remove FAT Directory Bread message
[linux-2.6.git] / fs / udf / misc.c
1 /*
2  * misc.c
3  *
4  * PURPOSE
5  *      Miscellaneous routines for the OSTA-UDF(tm) filesystem.
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  *  (C) 1998 Dave Boynton
14  *  (C) 1998-2004 Ben Fennema
15  *  (C) 1999-2000 Stelias Computing Inc
16  *
17  * HISTORY
18  *
19  *  04/19/99 blf  partial support for reading/writing specific EA's
20  */
21
22 #include "udfdecl.h"
23
24 #include <linux/fs.h>
25 #include <linux/string.h>
26 #include <linux/buffer_head.h>
27 #include <linux/crc-itu-t.h>
28
29 #include "udf_i.h"
30 #include "udf_sb.h"
31
32 struct buffer_head *udf_tgetblk(struct super_block *sb, int block)
33 {
34         if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
35                 return sb_getblk(sb, udf_fixed_to_variable(block));
36         else
37                 return sb_getblk(sb, block);
38 }
39
40 struct buffer_head *udf_tread(struct super_block *sb, int block)
41 {
42         if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
43                 return sb_bread(sb, udf_fixed_to_variable(block));
44         else
45                 return sb_bread(sb, block);
46 }
47
48 struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
49                                            uint32_t type, uint8_t loc)
50 {
51         uint8_t *ea = NULL, *ad = NULL;
52         int offset;
53         uint16_t crclen;
54         struct udf_inode_info *iinfo = UDF_I(inode);
55
56         ea = iinfo->i_ext.i_data;
57         if (iinfo->i_lenEAttr) {
58                 ad = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
59         } else {
60                 ad = ea;
61                 size += sizeof(struct extendedAttrHeaderDesc);
62         }
63
64         offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
65                 iinfo->i_lenAlloc;
66
67         /* TODO - Check for FreeEASpace */
68
69         if (loc & 0x01 && offset >= size) {
70                 struct extendedAttrHeaderDesc *eahd;
71                 eahd = (struct extendedAttrHeaderDesc *)ea;
72
73                 if (iinfo->i_lenAlloc)
74                         memmove(&ad[size], ad, iinfo->i_lenAlloc);
75
76                 if (iinfo->i_lenEAttr) {
77                         /* check checksum/crc */
78                         if (eahd->descTag.tagIdent !=
79                                         cpu_to_le16(TAG_IDENT_EAHD) ||
80                             le32_to_cpu(eahd->descTag.tagLocation) !=
81                                         iinfo->i_location.logicalBlockNum)
82                                 return NULL;
83                 } else {
84                         struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
85
86                         size -= sizeof(struct extendedAttrHeaderDesc);
87                         iinfo->i_lenEAttr +=
88                                 sizeof(struct extendedAttrHeaderDesc);
89                         eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
90                         if (sbi->s_udfrev >= 0x0200)
91                                 eahd->descTag.descVersion = cpu_to_le16(3);
92                         else
93                                 eahd->descTag.descVersion = cpu_to_le16(2);
94                         eahd->descTag.tagSerialNum =
95                                         cpu_to_le16(sbi->s_serial_number);
96                         eahd->descTag.tagLocation = cpu_to_le32(
97                                         iinfo->i_location.logicalBlockNum);
98                         eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
99                         eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
100                 }
101
102                 offset = iinfo->i_lenEAttr;
103                 if (type < 2048) {
104                         if (le32_to_cpu(eahd->appAttrLocation) <
105                                         iinfo->i_lenEAttr) {
106                                 uint32_t aal =
107                                         le32_to_cpu(eahd->appAttrLocation);
108                                 memmove(&ea[offset - aal + size],
109                                         &ea[aal], offset - aal);
110                                 offset -= aal;
111                                 eahd->appAttrLocation =
112                                                 cpu_to_le32(aal + size);
113                         }
114                         if (le32_to_cpu(eahd->impAttrLocation) <
115                                         iinfo->i_lenEAttr) {
116                                 uint32_t ial =
117                                         le32_to_cpu(eahd->impAttrLocation);
118                                 memmove(&ea[offset - ial + size],
119                                         &ea[ial], offset - ial);
120                                 offset -= ial;
121                                 eahd->impAttrLocation =
122                                                 cpu_to_le32(ial + size);
123                         }
124                 } else if (type < 65536) {
125                         if (le32_to_cpu(eahd->appAttrLocation) <
126                                         iinfo->i_lenEAttr) {
127                                 uint32_t aal =
128                                         le32_to_cpu(eahd->appAttrLocation);
129                                 memmove(&ea[offset - aal + size],
130                                         &ea[aal], offset - aal);
131                                 offset -= aal;
132                                 eahd->appAttrLocation =
133                                                 cpu_to_le32(aal + size);
134                         }
135                 }
136                 /* rewrite CRC + checksum of eahd */
137                 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(struct tag);
138                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
139                 eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
140                                                 sizeof(struct tag), crclen));
141                 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
142                 iinfo->i_lenEAttr += size;
143                 return (struct genericFormat *)&ea[offset];
144         }
145         if (loc & 0x02)
146                 ;
147
148         return NULL;
149 }
150
151 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
152                                            uint8_t subtype)
153 {
154         struct genericFormat *gaf;
155         uint8_t *ea = NULL;
156         uint32_t offset;
157         struct udf_inode_info *iinfo = UDF_I(inode);
158
159         ea = iinfo->i_ext.i_data;
160
161         if (iinfo->i_lenEAttr) {
162                 struct extendedAttrHeaderDesc *eahd;
163                 eahd = (struct extendedAttrHeaderDesc *)ea;
164
165                 /* check checksum/crc */
166                 if (eahd->descTag.tagIdent !=
167                                 cpu_to_le16(TAG_IDENT_EAHD) ||
168                     le32_to_cpu(eahd->descTag.tagLocation) !=
169                                 iinfo->i_location.logicalBlockNum)
170                         return NULL;
171
172                 if (type < 2048)
173                         offset = sizeof(struct extendedAttrHeaderDesc);
174                 else if (type < 65536)
175                         offset = le32_to_cpu(eahd->impAttrLocation);
176                 else
177                         offset = le32_to_cpu(eahd->appAttrLocation);
178
179                 while (offset < iinfo->i_lenEAttr) {
180                         gaf = (struct genericFormat *)&ea[offset];
181                         if (le32_to_cpu(gaf->attrType) == type &&
182                                         gaf->attrSubtype == subtype)
183                                 return gaf;
184                         else
185                                 offset += le32_to_cpu(gaf->attrLength);
186                 }
187         }
188
189         return NULL;
190 }
191
192 /*
193  * udf_read_tagged
194  *
195  * PURPOSE
196  *      Read the first block of a tagged descriptor.
197  *
198  * HISTORY
199  *      July 1, 1997 - Andrew E. Mileski
200  *      Written, tested, and released.
201  */
202 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
203                                     uint32_t location, uint16_t *ident)
204 {
205         struct tag *tag_p;
206         struct buffer_head *bh = NULL;
207
208         /* Read the block */
209         if (block == 0xFFFFFFFF)
210                 return NULL;
211
212         bh = udf_tread(sb, block);
213         if (!bh) {
214                 udf_debug("block=%d, location=%d: read failed\n",
215                           block, location);
216                 return NULL;
217         }
218
219         tag_p = (struct tag *)(bh->b_data);
220
221         *ident = le16_to_cpu(tag_p->tagIdent);
222
223         if (location != le32_to_cpu(tag_p->tagLocation)) {
224                 udf_debug("location mismatch block %u, tag %u != %u\n",
225                           block, le32_to_cpu(tag_p->tagLocation), location);
226                 goto error_out;
227         }
228
229         /* Verify the tag checksum */
230         if (udf_tag_checksum(tag_p) != tag_p->tagChecksum) {
231                 printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
232                 goto error_out;
233         }
234
235         /* Verify the tag version */
236         if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
237             tag_p->descVersion != cpu_to_le16(0x0003U)) {
238                 udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
239                           le16_to_cpu(tag_p->descVersion), block);
240                 goto error_out;
241         }
242
243         /* Verify the descriptor CRC */
244         if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
245             le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
246                                         bh->b_data + sizeof(struct tag),
247                                         le16_to_cpu(tag_p->descCRCLength)))
248                 return bh;
249
250         udf_debug("Crc failure block %d: crc = %d, crclen = %d\n", block,
251             le16_to_cpu(tag_p->descCRC), le16_to_cpu(tag_p->descCRCLength));
252
253 error_out:
254         brelse(bh);
255         return NULL;
256 }
257
258 struct buffer_head *udf_read_ptagged(struct super_block *sb,
259                                      struct kernel_lb_addr *loc,
260                                      uint32_t offset, uint16_t *ident)
261 {
262         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
263                                loc->logicalBlockNum + offset, ident);
264 }
265
266 void udf_update_tag(char *data, int length)
267 {
268         struct tag *tptr = (struct tag *)data;
269         length -= sizeof(struct tag);
270
271         tptr->descCRCLength = cpu_to_le16(length);
272         tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
273         tptr->tagChecksum = udf_tag_checksum(tptr);
274 }
275
276 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
277                  uint32_t loc, int length)
278 {
279         struct tag *tptr = (struct tag *)data;
280         tptr->tagIdent = cpu_to_le16(ident);
281         tptr->descVersion = cpu_to_le16(version);
282         tptr->tagSerialNum = cpu_to_le16(snum);
283         tptr->tagLocation = cpu_to_le32(loc);
284         udf_update_tag(data, length);
285 }
286
287 u8 udf_tag_checksum(const struct tag *t)
288 {
289         u8 *data = (u8 *)t;
290         u8 checksum = 0;
291         int i;
292         for (i = 0; i < sizeof(struct tag); ++i)
293                 if (i != 4) /* position of checksum */
294                         checksum += data[i];
295         return checksum;
296 }