Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 1 | /* |
| 2 | * QNX6 file system, Linux implementation. |
| 3 | * |
| 4 | * Version : 1.0.0 |
| 5 | * |
| 6 | * History : |
| 7 | * |
| 8 | * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release. |
| 9 | * 16-02-2012 pagemap extension by Al Viro |
| 10 | * |
| 11 | */ |
| 12 | |
| 13 | #include "qnx6.h" |
| 14 | |
| 15 | static unsigned qnx6_lfile_checksum(char *name, unsigned size) |
| 16 | { |
| 17 | unsigned crc = 0; |
| 18 | char *end = name + size; |
| 19 | while (name < end) { |
| 20 | crc = ((crc >> 1) + *(name++)) ^ |
| 21 | ((crc & 0x00000001) ? 0x80000000 : 0); |
| 22 | } |
| 23 | return crc; |
| 24 | } |
| 25 | |
| 26 | static struct page *qnx6_get_page(struct inode *dir, unsigned long n) |
| 27 | { |
| 28 | struct address_space *mapping = dir->i_mapping; |
| 29 | struct page *page = read_mapping_page(mapping, n, NULL); |
| 30 | if (!IS_ERR(page)) |
| 31 | kmap(page); |
| 32 | return page; |
| 33 | } |
| 34 | |
| 35 | static inline unsigned long dir_pages(struct inode *inode) |
| 36 | { |
| 37 | return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; |
| 38 | } |
| 39 | |
| 40 | static unsigned last_entry(struct inode *inode, unsigned long page_nr) |
| 41 | { |
| 42 | unsigned long last_byte = inode->i_size; |
| 43 | last_byte -= page_nr << PAGE_CACHE_SHIFT; |
| 44 | if (last_byte > PAGE_CACHE_SIZE) |
| 45 | last_byte = PAGE_CACHE_SIZE; |
| 46 | return last_byte / QNX6_DIR_ENTRY_SIZE; |
| 47 | } |
| 48 | |
| 49 | static struct qnx6_long_filename *qnx6_longname(struct super_block *sb, |
| 50 | struct qnx6_long_dir_entry *de, |
| 51 | struct page **p) |
| 52 | { |
| 53 | struct qnx6_sb_info *sbi = QNX6_SB(sb); |
| 54 | u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */ |
| 55 | u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */ |
| 56 | /* within page */ |
| 57 | u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK; |
| 58 | struct address_space *mapping = sbi->longfile->i_mapping; |
| 59 | struct page *page = read_mapping_page(mapping, n, NULL); |
| 60 | if (IS_ERR(page)) |
| 61 | return ERR_CAST(page); |
| 62 | kmap(*p = page); |
| 63 | return (struct qnx6_long_filename *)(page_address(page) + offs); |
| 64 | } |
| 65 | |
| 66 | static int qnx6_dir_longfilename(struct inode *inode, |
| 67 | struct qnx6_long_dir_entry *de, |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 68 | struct dir_context *ctx, |
| 69 | unsigned de_inode) |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 70 | { |
| 71 | struct qnx6_long_filename *lf; |
| 72 | struct super_block *s = inode->i_sb; |
| 73 | struct qnx6_sb_info *sbi = QNX6_SB(s); |
| 74 | struct page *page; |
| 75 | int lf_size; |
| 76 | |
| 77 | if (de->de_size != 0xff) { |
| 78 | /* error - long filename entries always have size 0xff |
| 79 | in direntry */ |
| 80 | printk(KERN_ERR "qnx6: invalid direntry size (%i).\n", |
| 81 | de->de_size); |
| 82 | return 0; |
| 83 | } |
| 84 | lf = qnx6_longname(s, de, &page); |
| 85 | if (IS_ERR(lf)) { |
| 86 | printk(KERN_ERR "qnx6:Error reading longname\n"); |
| 87 | return 0; |
| 88 | } |
| 89 | |
| 90 | lf_size = fs16_to_cpu(sbi, lf->lf_size); |
| 91 | |
| 92 | if (lf_size > QNX6_LONG_NAME_MAX) { |
| 93 | QNX6DEBUG((KERN_INFO "file %s\n", lf->lf_fname)); |
| 94 | printk(KERN_ERR "qnx6:Filename too long (%i)\n", lf_size); |
| 95 | qnx6_put_page(page); |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | /* calc & validate longfilename checksum |
| 100 | mmi 3g filesystem does not have that checksum */ |
| 101 | if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) != |
| 102 | qnx6_lfile_checksum(lf->lf_fname, lf_size)) |
| 103 | printk(KERN_INFO "qnx6: long filename checksum error.\n"); |
| 104 | |
| 105 | QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s inode:%u\n", |
| 106 | lf_size, lf->lf_fname, de_inode)); |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 107 | if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) { |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 108 | qnx6_put_page(page); |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | qnx6_put_page(page); |
| 113 | /* success */ |
| 114 | return 1; |
| 115 | } |
| 116 | |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 117 | static int qnx6_readdir(struct file *file, struct dir_context *ctx) |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 118 | { |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 119 | struct inode *inode = file_inode(file); |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 120 | struct super_block *s = inode->i_sb; |
| 121 | struct qnx6_sb_info *sbi = QNX6_SB(s); |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 122 | loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1); |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 123 | unsigned long npages = dir_pages(inode); |
| 124 | unsigned long n = pos >> PAGE_CACHE_SHIFT; |
| 125 | unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE; |
| 126 | bool done = false; |
| 127 | |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 128 | ctx->pos = pos; |
| 129 | if (ctx->pos >= inode->i_size) |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 130 | return 0; |
| 131 | |
| 132 | for ( ; !done && n < npages; n++, start = 0) { |
| 133 | struct page *page = qnx6_get_page(inode, n); |
| 134 | int limit = last_entry(inode, n); |
| 135 | struct qnx6_dir_entry *de; |
| 136 | int i = start; |
| 137 | |
| 138 | if (IS_ERR(page)) { |
| 139 | printk(KERN_ERR "qnx6_readdir: read failed\n"); |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 140 | ctx->pos = (n + 1) << PAGE_CACHE_SHIFT; |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 141 | return PTR_ERR(page); |
| 142 | } |
| 143 | de = ((struct qnx6_dir_entry *)page_address(page)) + start; |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 144 | for (; i < limit; i++, de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) { |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 145 | int size = de->de_size; |
| 146 | u32 no_inode = fs32_to_cpu(sbi, de->de_inode); |
| 147 | |
| 148 | if (!no_inode || !size) |
| 149 | continue; |
| 150 | |
| 151 | if (size > QNX6_SHORT_NAME_MAX) { |
| 152 | /* long filename detected |
| 153 | get the filename from long filename |
| 154 | structure / block */ |
| 155 | if (!qnx6_dir_longfilename(inode, |
| 156 | (struct qnx6_long_dir_entry *)de, |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 157 | ctx, no_inode)) { |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 158 | done = true; |
| 159 | break; |
| 160 | } |
| 161 | } else { |
| 162 | QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s" |
| 163 | " inode:%u\n", size, de->de_fname, |
| 164 | no_inode)); |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 165 | if (!dir_emit(ctx, de->de_fname, size, |
| 166 | no_inode, DT_UNKNOWN)) { |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 167 | done = true; |
| 168 | break; |
| 169 | } |
| 170 | } |
| 171 | } |
| 172 | qnx6_put_page(page); |
| 173 | } |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 174 | return 0; |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * check if the long filename is correct. |
| 179 | */ |
| 180 | static unsigned qnx6_long_match(int len, const char *name, |
| 181 | struct qnx6_long_dir_entry *de, struct inode *dir) |
| 182 | { |
| 183 | struct super_block *s = dir->i_sb; |
| 184 | struct qnx6_sb_info *sbi = QNX6_SB(s); |
| 185 | struct page *page; |
| 186 | int thislen; |
| 187 | struct qnx6_long_filename *lf = qnx6_longname(s, de, &page); |
| 188 | |
| 189 | if (IS_ERR(lf)) |
| 190 | return 0; |
| 191 | |
| 192 | thislen = fs16_to_cpu(sbi, lf->lf_size); |
| 193 | if (len != thislen) { |
| 194 | qnx6_put_page(page); |
| 195 | return 0; |
| 196 | } |
| 197 | if (memcmp(name, lf->lf_fname, len) == 0) { |
| 198 | qnx6_put_page(page); |
| 199 | return fs32_to_cpu(sbi, de->de_inode); |
| 200 | } |
| 201 | qnx6_put_page(page); |
| 202 | return 0; |
| 203 | } |
| 204 | |
| 205 | /* |
| 206 | * check if the filename is correct. |
| 207 | */ |
| 208 | static unsigned qnx6_match(struct super_block *s, int len, const char *name, |
| 209 | struct qnx6_dir_entry *de) |
| 210 | { |
| 211 | struct qnx6_sb_info *sbi = QNX6_SB(s); |
| 212 | if (memcmp(name, de->de_fname, len) == 0) |
| 213 | return fs32_to_cpu(sbi, de->de_inode); |
| 214 | return 0; |
| 215 | } |
| 216 | |
| 217 | |
| 218 | unsigned qnx6_find_entry(int len, struct inode *dir, const char *name, |
| 219 | struct page **res_page) |
| 220 | { |
| 221 | struct super_block *s = dir->i_sb; |
| 222 | struct qnx6_inode_info *ei = QNX6_I(dir); |
| 223 | struct page *page = NULL; |
| 224 | unsigned long start, n; |
| 225 | unsigned long npages = dir_pages(dir); |
| 226 | unsigned ino; |
| 227 | struct qnx6_dir_entry *de; |
| 228 | struct qnx6_long_dir_entry *lde; |
| 229 | |
| 230 | *res_page = NULL; |
| 231 | |
| 232 | if (npages == 0) |
| 233 | return 0; |
| 234 | start = ei->i_dir_start_lookup; |
| 235 | if (start >= npages) |
| 236 | start = 0; |
| 237 | n = start; |
| 238 | |
| 239 | do { |
| 240 | page = qnx6_get_page(dir, n); |
| 241 | if (!IS_ERR(page)) { |
| 242 | int limit = last_entry(dir, n); |
| 243 | int i; |
| 244 | |
| 245 | de = (struct qnx6_dir_entry *)page_address(page); |
| 246 | for (i = 0; i < limit; i++, de++) { |
| 247 | if (len <= QNX6_SHORT_NAME_MAX) { |
| 248 | /* short filename */ |
| 249 | if (len != de->de_size) |
| 250 | continue; |
| 251 | ino = qnx6_match(s, len, name, de); |
| 252 | if (ino) |
| 253 | goto found; |
| 254 | } else if (de->de_size == 0xff) { |
| 255 | /* deal with long filename */ |
| 256 | lde = (struct qnx6_long_dir_entry *)de; |
| 257 | ino = qnx6_long_match(len, |
| 258 | name, lde, dir); |
| 259 | if (ino) |
| 260 | goto found; |
| 261 | } else |
| 262 | printk(KERN_ERR "qnx6: undefined " |
| 263 | "filename size in inode.\n"); |
| 264 | } |
| 265 | qnx6_put_page(page); |
| 266 | } |
| 267 | |
| 268 | if (++n >= npages) |
| 269 | n = 0; |
| 270 | } while (n != start); |
| 271 | return 0; |
| 272 | |
| 273 | found: |
| 274 | *res_page = page; |
| 275 | ei->i_dir_start_lookup = n; |
| 276 | return ino; |
| 277 | } |
| 278 | |
| 279 | const struct file_operations qnx6_dir_operations = { |
| 280 | .llseek = generic_file_llseek, |
| 281 | .read = generic_read_dir, |
Al Viro | 4deb398 | 2013-05-17 15:32:10 -0400 | [diff] [blame^] | 282 | .iterate = qnx6_readdir, |
Kai Bankett | 5d026c7 | 2012-02-17 05:59:20 +0100 | [diff] [blame] | 283 | .fsync = generic_file_fsync, |
| 284 | }; |
| 285 | |
| 286 | const struct inode_operations qnx6_dir_inode_operations = { |
| 287 | .lookup = qnx6_lookup, |
| 288 | }; |