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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, | |
4deb398a AV |
68 | struct dir_context *ctx, |
69 | unsigned de_inode) | |
5d026c72 KB |
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 */ | |
e6c32616 | 80 | pr_err("invalid direntry size (%i).\n", de->de_size); |
5d026c72 KB |
81 | return 0; |
82 | } | |
83 | lf = qnx6_longname(s, de, &page); | |
84 | if (IS_ERR(lf)) { | |
e6c32616 | 85 | pr_err("Error reading longname\n"); |
5d026c72 KB |
86 | return 0; |
87 | } | |
88 | ||
89 | lf_size = fs16_to_cpu(sbi, lf->lf_size); | |
90 | ||
91 | if (lf_size > QNX6_LONG_NAME_MAX) { | |
92 | QNX6DEBUG((KERN_INFO "file %s\n", lf->lf_fname)); | |
e6c32616 | 93 | pr_err("Filename too long (%i)\n", lf_size); |
5d026c72 KB |
94 | qnx6_put_page(page); |
95 | return 0; | |
96 | } | |
97 | ||
98 | /* calc & validate longfilename checksum | |
99 | mmi 3g filesystem does not have that checksum */ | |
100 | if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) != | |
101 | qnx6_lfile_checksum(lf->lf_fname, lf_size)) | |
e6c32616 | 102 | pr_info("long filename checksum error.\n"); |
5d026c72 KB |
103 | |
104 | QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s inode:%u\n", | |
105 | lf_size, lf->lf_fname, de_inode)); | |
4deb398a | 106 | if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) { |
5d026c72 KB |
107 | qnx6_put_page(page); |
108 | return 0; | |
109 | } | |
110 | ||
111 | qnx6_put_page(page); | |
112 | /* success */ | |
113 | return 1; | |
114 | } | |
115 | ||
4deb398a | 116 | static int qnx6_readdir(struct file *file, struct dir_context *ctx) |
5d026c72 | 117 | { |
4deb398a | 118 | struct inode *inode = file_inode(file); |
5d026c72 KB |
119 | struct super_block *s = inode->i_sb; |
120 | struct qnx6_sb_info *sbi = QNX6_SB(s); | |
4deb398a | 121 | loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1); |
5d026c72 KB |
122 | unsigned long npages = dir_pages(inode); |
123 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | |
124 | unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE; | |
125 | bool done = false; | |
126 | ||
4deb398a AV |
127 | ctx->pos = pos; |
128 | if (ctx->pos >= inode->i_size) | |
5d026c72 KB |
129 | return 0; |
130 | ||
131 | for ( ; !done && n < npages; n++, start = 0) { | |
132 | struct page *page = qnx6_get_page(inode, n); | |
133 | int limit = last_entry(inode, n); | |
134 | struct qnx6_dir_entry *de; | |
135 | int i = start; | |
136 | ||
137 | if (IS_ERR(page)) { | |
e6c32616 | 138 | pr_err("%s(): read failed\n", __func__); |
4deb398a | 139 | ctx->pos = (n + 1) << PAGE_CACHE_SHIFT; |
5d026c72 KB |
140 | return PTR_ERR(page); |
141 | } | |
142 | de = ((struct qnx6_dir_entry *)page_address(page)) + start; | |
4deb398a | 143 | for (; i < limit; i++, de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) { |
5d026c72 KB |
144 | int size = de->de_size; |
145 | u32 no_inode = fs32_to_cpu(sbi, de->de_inode); | |
146 | ||
147 | if (!no_inode || !size) | |
148 | continue; | |
149 | ||
150 | if (size > QNX6_SHORT_NAME_MAX) { | |
151 | /* long filename detected | |
152 | get the filename from long filename | |
153 | structure / block */ | |
154 | if (!qnx6_dir_longfilename(inode, | |
155 | (struct qnx6_long_dir_entry *)de, | |
4deb398a | 156 | ctx, no_inode)) { |
5d026c72 KB |
157 | done = true; |
158 | break; | |
159 | } | |
160 | } else { | |
161 | QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s" | |
162 | " inode:%u\n", size, de->de_fname, | |
163 | no_inode)); | |
4deb398a AV |
164 | if (!dir_emit(ctx, de->de_fname, size, |
165 | no_inode, DT_UNKNOWN)) { | |
5d026c72 KB |
166 | done = true; |
167 | break; | |
168 | } | |
169 | } | |
170 | } | |
171 | qnx6_put_page(page); | |
172 | } | |
5d026c72 KB |
173 | return 0; |
174 | } | |
175 | ||
176 | /* | |
177 | * check if the long filename is correct. | |
178 | */ | |
179 | static unsigned qnx6_long_match(int len, const char *name, | |
180 | struct qnx6_long_dir_entry *de, struct inode *dir) | |
181 | { | |
182 | struct super_block *s = dir->i_sb; | |
183 | struct qnx6_sb_info *sbi = QNX6_SB(s); | |
184 | struct page *page; | |
185 | int thislen; | |
186 | struct qnx6_long_filename *lf = qnx6_longname(s, de, &page); | |
187 | ||
188 | if (IS_ERR(lf)) | |
189 | return 0; | |
190 | ||
191 | thislen = fs16_to_cpu(sbi, lf->lf_size); | |
192 | if (len != thislen) { | |
193 | qnx6_put_page(page); | |
194 | return 0; | |
195 | } | |
196 | if (memcmp(name, lf->lf_fname, len) == 0) { | |
197 | qnx6_put_page(page); | |
198 | return fs32_to_cpu(sbi, de->de_inode); | |
199 | } | |
200 | qnx6_put_page(page); | |
201 | return 0; | |
202 | } | |
203 | ||
204 | /* | |
205 | * check if the filename is correct. | |
206 | */ | |
207 | static unsigned qnx6_match(struct super_block *s, int len, const char *name, | |
208 | struct qnx6_dir_entry *de) | |
209 | { | |
210 | struct qnx6_sb_info *sbi = QNX6_SB(s); | |
211 | if (memcmp(name, de->de_fname, len) == 0) | |
212 | return fs32_to_cpu(sbi, de->de_inode); | |
213 | return 0; | |
214 | } | |
215 | ||
216 | ||
217 | unsigned qnx6_find_entry(int len, struct inode *dir, const char *name, | |
218 | struct page **res_page) | |
219 | { | |
220 | struct super_block *s = dir->i_sb; | |
221 | struct qnx6_inode_info *ei = QNX6_I(dir); | |
222 | struct page *page = NULL; | |
223 | unsigned long start, n; | |
224 | unsigned long npages = dir_pages(dir); | |
225 | unsigned ino; | |
226 | struct qnx6_dir_entry *de; | |
227 | struct qnx6_long_dir_entry *lde; | |
228 | ||
229 | *res_page = NULL; | |
230 | ||
231 | if (npages == 0) | |
232 | return 0; | |
233 | start = ei->i_dir_start_lookup; | |
234 | if (start >= npages) | |
235 | start = 0; | |
236 | n = start; | |
237 | ||
238 | do { | |
239 | page = qnx6_get_page(dir, n); | |
240 | if (!IS_ERR(page)) { | |
241 | int limit = last_entry(dir, n); | |
242 | int i; | |
243 | ||
244 | de = (struct qnx6_dir_entry *)page_address(page); | |
245 | for (i = 0; i < limit; i++, de++) { | |
246 | if (len <= QNX6_SHORT_NAME_MAX) { | |
247 | /* short filename */ | |
248 | if (len != de->de_size) | |
249 | continue; | |
250 | ino = qnx6_match(s, len, name, de); | |
251 | if (ino) | |
252 | goto found; | |
253 | } else if (de->de_size == 0xff) { | |
254 | /* deal with long filename */ | |
255 | lde = (struct qnx6_long_dir_entry *)de; | |
256 | ino = qnx6_long_match(len, | |
257 | name, lde, dir); | |
258 | if (ino) | |
259 | goto found; | |
260 | } else | |
e6c32616 | 261 | pr_err("undefined filename size in inode.\n"); |
5d026c72 KB |
262 | } |
263 | qnx6_put_page(page); | |
264 | } | |
265 | ||
266 | if (++n >= npages) | |
267 | n = 0; | |
268 | } while (n != start); | |
269 | return 0; | |
270 | ||
271 | found: | |
272 | *res_page = page; | |
273 | ei->i_dir_start_lookup = n; | |
274 | return ino; | |
275 | } | |
276 | ||
277 | const struct file_operations qnx6_dir_operations = { | |
278 | .llseek = generic_file_llseek, | |
279 | .read = generic_read_dir, | |
4deb398a | 280 | .iterate = qnx6_readdir, |
5d026c72 KB |
281 | .fsync = generic_file_fsync, |
282 | }; | |
283 | ||
284 | const struct inode_operations qnx6_dir_inode_operations = { | |
285 | .lookup = qnx6_lookup, | |
286 | }; |