Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Compressed rom filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 1999 Linus Torvalds. | |
5 | * | |
6 | * This file is released under the GPL. | |
7 | */ | |
8 | ||
9 | /* | |
10 | * These are the VFS interfaces to the compressed rom filesystem. | |
11 | * The actual compression is based on zlib, see the other files. | |
12 | */ | |
13 | ||
4f21e1ea FF |
14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
15 | ||
1da177e4 LT |
16 | #include <linux/module.h> |
17 | #include <linux/fs.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/string.h> | |
21 | #include <linux/blkdev.h> | |
1da177e4 | 22 | #include <linux/slab.h> |
1da177e4 | 23 | #include <linux/vfs.h> |
353ab6e9 | 24 | #include <linux/mutex.h> |
f7f4f4dd | 25 | #include <uapi/linux/cramfs_fs.h> |
1508f3eb | 26 | #include <linux/uaccess.h> |
1da177e4 | 27 | |
f7f4f4dd AV |
28 | #include "internal.h" |
29 | ||
30 | /* | |
31 | * cramfs super-block data in memory | |
32 | */ | |
33 | struct cramfs_sb_info { | |
34 | unsigned long magic; | |
35 | unsigned long size; | |
36 | unsigned long blocks; | |
37 | unsigned long files; | |
38 | unsigned long flags; | |
39 | }; | |
40 | ||
41 | static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb) | |
42 | { | |
43 | return sb->s_fs_info; | |
44 | } | |
45 | ||
ee9b6d61 | 46 | static const struct super_operations cramfs_ops; |
754661f1 | 47 | static const struct inode_operations cramfs_dir_inode_operations; |
4b6f5d20 | 48 | static const struct file_operations cramfs_directory_operations; |
f5e54d6e | 49 | static const struct address_space_operations cramfs_aops; |
1da177e4 | 50 | |
353ab6e9 | 51 | static DEFINE_MUTEX(read_mutex); |
1da177e4 LT |
52 | |
53 | ||
6f772fe6 | 54 | /* These macros may change in future, to provide better st_ino semantics. */ |
1da177e4 LT |
55 | #define OFFSET(x) ((x)->i_ino) |
56 | ||
0577d1ba | 57 | static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset) |
a97c9bf3 | 58 | { |
6f772fe6 SS |
59 | if (!cino->offset) |
60 | return offset + 1; | |
61 | if (!cino->size) | |
62 | return offset + 1; | |
63 | ||
64 | /* | |
65 | * The file mode test fixes buggy mkcramfs implementations where | |
66 | * cramfs_inode->offset is set to a non zero value for entries | |
67 | * which did not contain data, like devices node and fifos. | |
68 | */ | |
69 | switch (cino->mode & S_IFMT) { | |
70 | case S_IFREG: | |
71 | case S_IFDIR: | |
72 | case S_IFLNK: | |
73 | return cino->offset << 2; | |
74 | default: | |
75 | break; | |
76 | } | |
77 | return offset + 1; | |
78 | } | |
79 | ||
80 | static struct inode *get_cramfs_inode(struct super_block *sb, | |
0577d1ba | 81 | const struct cramfs_inode *cramfs_inode, unsigned int offset) |
6f772fe6 SS |
82 | { |
83 | struct inode *inode; | |
77b8a75f | 84 | static struct timespec zerotime; |
6f772fe6 SS |
85 | |
86 | inode = iget_locked(sb, cramino(cramfs_inode, offset)); | |
87 | if (!inode) | |
88 | return ERR_PTR(-ENOMEM); | |
89 | if (!(inode->i_state & I_NEW)) | |
90 | return inode; | |
91 | ||
92 | switch (cramfs_inode->mode & S_IFMT) { | |
93 | case S_IFREG: | |
94 | inode->i_fop = &generic_ro_fops; | |
95 | inode->i_data.a_ops = &cramfs_aops; | |
96 | break; | |
97 | case S_IFDIR: | |
98 | inode->i_op = &cramfs_dir_inode_operations; | |
99 | inode->i_fop = &cramfs_directory_operations; | |
100 | break; | |
101 | case S_IFLNK: | |
102 | inode->i_op = &page_symlink_inode_operations; | |
103 | inode->i_data.a_ops = &cramfs_aops; | |
104 | break; | |
105 | default: | |
106 | init_special_inode(inode, cramfs_inode->mode, | |
107 | old_decode_dev(cramfs_inode->size)); | |
108 | } | |
109 | ||
77b8a75f | 110 | inode->i_mode = cramfs_inode->mode; |
a7d9cfe9 EB |
111 | i_uid_write(inode, cramfs_inode->uid); |
112 | i_gid_write(inode, cramfs_inode->gid); | |
6f772fe6 SS |
113 | |
114 | /* if the lower 2 bits are zero, the inode contains data */ | |
115 | if (!(inode->i_ino & 3)) { | |
116 | inode->i_size = cramfs_inode->size; | |
117 | inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1; | |
118 | } | |
119 | ||
77b8a75f AV |
120 | /* Struct copy intentional */ |
121 | inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime; | |
122 | /* inode->i_nlink is left 1 - arguably wrong for directories, | |
123 | but it's the best we can do without reading the directory | |
124 | contents. 1 yields the right result in GNU find, even | |
125 | without -noleaf option. */ | |
a97c9bf3 | 126 | |
6f772fe6 SS |
127 | unlock_new_inode(inode); |
128 | ||
1da177e4 LT |
129 | return inode; |
130 | } | |
131 | ||
132 | /* | |
133 | * We have our own block cache: don't fill up the buffer cache | |
134 | * with the rom-image, because the way the filesystem is set | |
135 | * up the accesses should be fairly regular and cached in the | |
136 | * page cache and dentry tree anyway.. | |
137 | * | |
138 | * This also acts as a way to guarantee contiguous areas of up to | |
139 | * BLKS_PER_BUF*PAGE_CACHE_SIZE, so that the caller doesn't need to | |
140 | * worry about end-of-buffer issues even when decompressing a full | |
141 | * page cache. | |
142 | */ | |
143 | #define READ_BUFFERS (2) | |
144 | /* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */ | |
145 | #define NEXT_BUFFER(_ix) ((_ix) ^ 1) | |
146 | ||
147 | /* | |
148 | * BLKS_PER_BUF_SHIFT should be at least 2 to allow for "compressed" | |
149 | * data that takes up more space than the original and with unlucky | |
150 | * alignment. | |
151 | */ | |
152 | #define BLKS_PER_BUF_SHIFT (2) | |
153 | #define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT) | |
154 | #define BUFFER_SIZE (BLKS_PER_BUF*PAGE_CACHE_SIZE) | |
155 | ||
156 | static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE]; | |
157 | static unsigned buffer_blocknr[READ_BUFFERS]; | |
31d92e55 | 158 | static struct super_block *buffer_dev[READ_BUFFERS]; |
1da177e4 LT |
159 | static int next_buffer; |
160 | ||
161 | /* | |
162 | * Returns a pointer to a buffer containing at least LEN bytes of | |
163 | * filesystem starting at byte offset OFFSET into the filesystem. | |
164 | */ | |
165 | static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned int len) | |
166 | { | |
167 | struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; | |
168 | struct page *pages[BLKS_PER_BUF]; | |
6bbfb077 | 169 | unsigned i, blocknr, buffer; |
1da177e4 LT |
170 | unsigned long devsize; |
171 | char *data; | |
172 | ||
173 | if (!len) | |
174 | return NULL; | |
175 | blocknr = offset >> PAGE_CACHE_SHIFT; | |
176 | offset &= PAGE_CACHE_SIZE - 1; | |
177 | ||
178 | /* Check if an existing buffer already has the data.. */ | |
179 | for (i = 0; i < READ_BUFFERS; i++) { | |
180 | unsigned int blk_offset; | |
181 | ||
182 | if (buffer_dev[i] != sb) | |
183 | continue; | |
184 | if (blocknr < buffer_blocknr[i]) | |
185 | continue; | |
186 | blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_SHIFT; | |
187 | blk_offset += offset; | |
188 | if (blk_offset + len > BUFFER_SIZE) | |
189 | continue; | |
190 | return read_buffers[i] + blk_offset; | |
191 | } | |
192 | ||
193 | devsize = mapping->host->i_size >> PAGE_CACHE_SHIFT; | |
194 | ||
195 | /* Ok, read in BLKS_PER_BUF pages completely first. */ | |
1da177e4 LT |
196 | for (i = 0; i < BLKS_PER_BUF; i++) { |
197 | struct page *page = NULL; | |
198 | ||
199 | if (blocknr + i < devsize) { | |
67f9fd91 | 200 | page = read_mapping_page(mapping, blocknr + i, NULL); |
1da177e4 LT |
201 | /* synchronous error? */ |
202 | if (IS_ERR(page)) | |
203 | page = NULL; | |
204 | } | |
205 | pages[i] = page; | |
206 | } | |
207 | ||
208 | for (i = 0; i < BLKS_PER_BUF; i++) { | |
209 | struct page *page = pages[i]; | |
31d92e55 | 210 | |
1da177e4 LT |
211 | if (page) { |
212 | wait_on_page_locked(page); | |
213 | if (!PageUptodate(page)) { | |
214 | /* asynchronous error */ | |
215 | page_cache_release(page); | |
216 | pages[i] = NULL; | |
217 | } | |
218 | } | |
219 | } | |
220 | ||
221 | buffer = next_buffer; | |
222 | next_buffer = NEXT_BUFFER(buffer); | |
223 | buffer_blocknr[buffer] = blocknr; | |
224 | buffer_dev[buffer] = sb; | |
225 | ||
226 | data = read_buffers[buffer]; | |
227 | for (i = 0; i < BLKS_PER_BUF; i++) { | |
228 | struct page *page = pages[i]; | |
31d92e55 | 229 | |
1da177e4 LT |
230 | if (page) { |
231 | memcpy(data, kmap(page), PAGE_CACHE_SIZE); | |
232 | kunmap(page); | |
233 | page_cache_release(page); | |
234 | } else | |
235 | memset(data, 0, PAGE_CACHE_SIZE); | |
236 | data += PAGE_CACHE_SIZE; | |
237 | } | |
238 | return read_buffers[buffer] + offset; | |
239 | } | |
240 | ||
2309fb8e | 241 | static void cramfs_kill_sb(struct super_block *sb) |
1da177e4 | 242 | { |
f7f4f4dd | 243 | struct cramfs_sb_info *sbi = CRAMFS_SB(sb); |
31d92e55 | 244 | |
2309fb8e AV |
245 | kill_block_super(sb); |
246 | kfree(sbi); | |
1da177e4 LT |
247 | } |
248 | ||
249 | static int cramfs_remount(struct super_block *sb, int *flags, char *data) | |
250 | { | |
02b9984d | 251 | sync_filesystem(sb); |
1da177e4 LT |
252 | *flags |= MS_RDONLY; |
253 | return 0; | |
254 | } | |
255 | ||
256 | static int cramfs_fill_super(struct super_block *sb, void *data, int silent) | |
257 | { | |
258 | int i; | |
259 | struct cramfs_super super; | |
260 | unsigned long root_offset; | |
261 | struct cramfs_sb_info *sbi; | |
262 | struct inode *root; | |
263 | ||
264 | sb->s_flags |= MS_RDONLY; | |
265 | ||
f8314dc6 | 266 | sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL); |
1da177e4 LT |
267 | if (!sbi) |
268 | return -ENOMEM; | |
269 | sb->s_fs_info = sbi; | |
1da177e4 LT |
270 | |
271 | /* Invalidate the read buffers on mount: think disk change.. */ | |
353ab6e9 | 272 | mutex_lock(&read_mutex); |
1da177e4 LT |
273 | for (i = 0; i < READ_BUFFERS; i++) |
274 | buffer_blocknr[i] = -1; | |
275 | ||
276 | /* Read the first block and get the superblock from it */ | |
277 | memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super)); | |
353ab6e9 | 278 | mutex_unlock(&read_mutex); |
1da177e4 LT |
279 | |
280 | /* Do sanity checks on the superblock */ | |
281 | if (super.magic != CRAMFS_MAGIC) { | |
0cc785ec | 282 | /* check for wrong endianness */ |
ac8d35c5 AD |
283 | if (super.magic == CRAMFS_MAGIC_WEND) { |
284 | if (!silent) | |
4f21e1ea | 285 | pr_err("wrong endianness\n"); |
2309fb8e | 286 | return -EINVAL; |
ac8d35c5 AD |
287 | } |
288 | ||
1da177e4 | 289 | /* check at 512 byte offset */ |
353ab6e9 | 290 | mutex_lock(&read_mutex); |
1da177e4 | 291 | memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super)); |
353ab6e9 | 292 | mutex_unlock(&read_mutex); |
1da177e4 | 293 | if (super.magic != CRAMFS_MAGIC) { |
ac8d35c5 | 294 | if (super.magic == CRAMFS_MAGIC_WEND && !silent) |
4f21e1ea | 295 | pr_err("wrong endianness\n"); |
ac8d35c5 | 296 | else if (!silent) |
4f21e1ea | 297 | pr_err("wrong magic\n"); |
2309fb8e | 298 | return -EINVAL; |
1da177e4 LT |
299 | } |
300 | } | |
301 | ||
302 | /* get feature flags first */ | |
303 | if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) { | |
4f21e1ea | 304 | pr_err("unsupported filesystem features\n"); |
2309fb8e | 305 | return -EINVAL; |
1da177e4 LT |
306 | } |
307 | ||
308 | /* Check that the root inode is in a sane state */ | |
309 | if (!S_ISDIR(super.root.mode)) { | |
4f21e1ea | 310 | pr_err("root is not a directory\n"); |
2309fb8e | 311 | return -EINVAL; |
1da177e4 | 312 | } |
6f772fe6 SS |
313 | /* correct strange, hard-coded permissions of mkcramfs */ |
314 | super.root.mode |= (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH); | |
315 | ||
1da177e4 LT |
316 | root_offset = super.root.offset << 2; |
317 | if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) { | |
31d92e55 FF |
318 | sbi->size = super.size; |
319 | sbi->blocks = super.fsid.blocks; | |
320 | sbi->files = super.fsid.files; | |
1da177e4 | 321 | } else { |
31d92e55 FF |
322 | sbi->size = 1<<28; |
323 | sbi->blocks = 0; | |
324 | sbi->files = 0; | |
1da177e4 | 325 | } |
31d92e55 FF |
326 | sbi->magic = super.magic; |
327 | sbi->flags = super.flags; | |
1da177e4 | 328 | if (root_offset == 0) |
4f21e1ea | 329 | pr_info("empty filesystem"); |
1da177e4 LT |
330 | else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) && |
331 | ((root_offset != sizeof(struct cramfs_super)) && | |
332 | (root_offset != 512 + sizeof(struct cramfs_super)))) | |
333 | { | |
4f21e1ea | 334 | pr_err("bad root offset %lu\n", root_offset); |
2309fb8e | 335 | return -EINVAL; |
1da177e4 LT |
336 | } |
337 | ||
338 | /* Set it all up.. */ | |
339 | sb->s_op = &cramfs_ops; | |
6f772fe6 | 340 | root = get_cramfs_inode(sb, &super.root, 0); |
0577d1ba | 341 | if (IS_ERR(root)) |
2309fb8e | 342 | return PTR_ERR(root); |
48fde701 AV |
343 | sb->s_root = d_make_root(root); |
344 | if (!sb->s_root) | |
2309fb8e | 345 | return -ENOMEM; |
1da177e4 | 346 | return 0; |
1da177e4 LT |
347 | } |
348 | ||
726c3342 | 349 | static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 350 | { |
726c3342 | 351 | struct super_block *sb = dentry->d_sb; |
94ea77ac | 352 | u64 id = huge_encode_dev(sb->s_bdev->bd_dev); |
726c3342 | 353 | |
1da177e4 LT |
354 | buf->f_type = CRAMFS_MAGIC; |
355 | buf->f_bsize = PAGE_CACHE_SIZE; | |
356 | buf->f_blocks = CRAMFS_SB(sb)->blocks; | |
357 | buf->f_bfree = 0; | |
358 | buf->f_bavail = 0; | |
359 | buf->f_files = CRAMFS_SB(sb)->files; | |
360 | buf->f_ffree = 0; | |
94ea77ac CL |
361 | buf->f_fsid.val[0] = (u32)id; |
362 | buf->f_fsid.val[1] = (u32)(id >> 32); | |
1da177e4 LT |
363 | buf->f_namelen = CRAMFS_MAXPATHLEN; |
364 | return 0; | |
365 | } | |
366 | ||
367 | /* | |
368 | * Read a cramfs directory entry. | |
369 | */ | |
6f7f231e | 370 | static int cramfs_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 371 | { |
6f7f231e | 372 | struct inode *inode = file_inode(file); |
1da177e4 LT |
373 | struct super_block *sb = inode->i_sb; |
374 | char *buf; | |
375 | unsigned int offset; | |
1da177e4 LT |
376 | |
377 | /* Offset within the thing. */ | |
6f7f231e | 378 | if (ctx->pos >= inode->i_size) |
1da177e4 | 379 | return 0; |
6f7f231e | 380 | offset = ctx->pos; |
1da177e4 LT |
381 | /* Directory entries are always 4-byte aligned */ |
382 | if (offset & 3) | |
383 | return -EINVAL; | |
384 | ||
4176ed59 | 385 | buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL); |
1da177e4 LT |
386 | if (!buf) |
387 | return -ENOMEM; | |
388 | ||
1da177e4 LT |
389 | while (offset < inode->i_size) { |
390 | struct cramfs_inode *de; | |
391 | unsigned long nextoffset; | |
392 | char *name; | |
393 | ino_t ino; | |
175a4eb7 | 394 | umode_t mode; |
6f7f231e | 395 | int namelen; |
1da177e4 | 396 | |
353ab6e9 | 397 | mutex_lock(&read_mutex); |
4176ed59 | 398 | de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN); |
1da177e4 LT |
399 | name = (char *)(de+1); |
400 | ||
401 | /* | |
402 | * Namelengths on disk are shifted by two | |
403 | * and the name padded out to 4-byte boundaries | |
404 | * with zeroes. | |
405 | */ | |
406 | namelen = de->namelen << 2; | |
407 | memcpy(buf, name, namelen); | |
6f772fe6 | 408 | ino = cramino(de, OFFSET(inode) + offset); |
1da177e4 | 409 | mode = de->mode; |
353ab6e9 | 410 | mutex_unlock(&read_mutex); |
1da177e4 LT |
411 | nextoffset = offset + sizeof(*de) + namelen; |
412 | for (;;) { | |
413 | if (!namelen) { | |
414 | kfree(buf); | |
415 | return -EIO; | |
416 | } | |
417 | if (buf[namelen-1]) | |
418 | break; | |
419 | namelen--; | |
420 | } | |
6f7f231e | 421 | if (!dir_emit(ctx, buf, namelen, ino, mode >> 12)) |
1da177e4 LT |
422 | break; |
423 | ||
6f7f231e | 424 | ctx->pos = offset = nextoffset; |
1da177e4 LT |
425 | } |
426 | kfree(buf); | |
427 | return 0; | |
428 | } | |
429 | ||
430 | /* | |
431 | * Lookup and fill in the inode data.. | |
432 | */ | |
31d92e55 | 433 | static struct dentry *cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 LT |
434 | { |
435 | unsigned int offset = 0; | |
0577d1ba | 436 | struct inode *inode = NULL; |
1da177e4 LT |
437 | int sorted; |
438 | ||
353ab6e9 | 439 | mutex_lock(&read_mutex); |
1da177e4 LT |
440 | sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS; |
441 | while (offset < dir->i_size) { | |
442 | struct cramfs_inode *de; | |
443 | char *name; | |
444 | int namelen, retval; | |
6f772fe6 | 445 | int dir_off = OFFSET(dir) + offset; |
1da177e4 | 446 | |
6f772fe6 | 447 | de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN); |
1da177e4 LT |
448 | name = (char *)(de+1); |
449 | ||
450 | /* Try to take advantage of sorted directories */ | |
451 | if (sorted && (dentry->d_name.name[0] < name[0])) | |
452 | break; | |
453 | ||
454 | namelen = de->namelen << 2; | |
455 | offset += sizeof(*de) + namelen; | |
456 | ||
457 | /* Quick check that the name is roughly the right length */ | |
458 | if (((dentry->d_name.len + 3) & ~3) != namelen) | |
459 | continue; | |
460 | ||
461 | for (;;) { | |
462 | if (!namelen) { | |
0577d1ba AV |
463 | inode = ERR_PTR(-EIO); |
464 | goto out; | |
1da177e4 LT |
465 | } |
466 | if (name[namelen-1]) | |
467 | break; | |
468 | namelen--; | |
469 | } | |
470 | if (namelen != dentry->d_name.len) | |
471 | continue; | |
472 | retval = memcmp(dentry->d_name.name, name, namelen); | |
473 | if (retval > 0) | |
474 | continue; | |
475 | if (!retval) { | |
0577d1ba AV |
476 | inode = get_cramfs_inode(dir->i_sb, de, dir_off); |
477 | break; | |
1da177e4 LT |
478 | } |
479 | /* else (retval < 0) */ | |
480 | if (sorted) | |
481 | break; | |
482 | } | |
0577d1ba | 483 | out: |
353ab6e9 | 484 | mutex_unlock(&read_mutex); |
0577d1ba AV |
485 | if (IS_ERR(inode)) |
486 | return ERR_CAST(inode); | |
487 | d_add(dentry, inode); | |
1da177e4 LT |
488 | return NULL; |
489 | } | |
490 | ||
31d92e55 | 491 | static int cramfs_readpage(struct file *file, struct page *page) |
1da177e4 LT |
492 | { |
493 | struct inode *inode = page->mapping->host; | |
98310e58 DV |
494 | u32 maxblock; |
495 | int bytes_filled; | |
1da177e4 LT |
496 | void *pgdata; |
497 | ||
498 | maxblock = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
499 | bytes_filled = 0; | |
98310e58 DV |
500 | pgdata = kmap(page); |
501 | ||
1da177e4 LT |
502 | if (page->index < maxblock) { |
503 | struct super_block *sb = inode->i_sb; | |
504 | u32 blkptr_offset = OFFSET(inode) + page->index*4; | |
505 | u32 start_offset, compr_len; | |
506 | ||
507 | start_offset = OFFSET(inode) + maxblock*4; | |
353ab6e9 | 508 | mutex_lock(&read_mutex); |
1da177e4 | 509 | if (page->index) |
98310e58 DV |
510 | start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4, |
511 | 4); | |
512 | compr_len = (*(u32 *) cramfs_read(sb, blkptr_offset, 4) - | |
513 | start_offset); | |
353ab6e9 | 514 | mutex_unlock(&read_mutex); |
98310e58 | 515 | |
1da177e4 LT |
516 | if (compr_len == 0) |
517 | ; /* hole */ | |
98310e58 | 518 | else if (unlikely(compr_len > (PAGE_CACHE_SIZE << 1))) { |
4f21e1ea | 519 | pr_err("bad compressed blocksize %u\n", |
98310e58 DV |
520 | compr_len); |
521 | goto err; | |
522 | } else { | |
353ab6e9 | 523 | mutex_lock(&read_mutex); |
1da177e4 LT |
524 | bytes_filled = cramfs_uncompress_block(pgdata, |
525 | PAGE_CACHE_SIZE, | |
526 | cramfs_read(sb, start_offset, compr_len), | |
527 | compr_len); | |
353ab6e9 | 528 | mutex_unlock(&read_mutex); |
98310e58 DV |
529 | if (unlikely(bytes_filled < 0)) |
530 | goto err; | |
1da177e4 | 531 | } |
98310e58 DV |
532 | } |
533 | ||
1da177e4 | 534 | memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled); |
1da177e4 | 535 | flush_dcache_page(page); |
98310e58 | 536 | kunmap(page); |
1da177e4 LT |
537 | SetPageUptodate(page); |
538 | unlock_page(page); | |
539 | return 0; | |
98310e58 DV |
540 | |
541 | err: | |
542 | kunmap(page); | |
543 | ClearPageUptodate(page); | |
544 | SetPageError(page); | |
545 | unlock_page(page); | |
546 | return 0; | |
1da177e4 LT |
547 | } |
548 | ||
f5e54d6e | 549 | static const struct address_space_operations cramfs_aops = { |
1da177e4 LT |
550 | .readpage = cramfs_readpage |
551 | }; | |
552 | ||
553 | /* | |
554 | * Our operations: | |
555 | */ | |
556 | ||
557 | /* | |
558 | * A directory can only readdir | |
559 | */ | |
4b6f5d20 | 560 | static const struct file_operations cramfs_directory_operations = { |
1da177e4 LT |
561 | .llseek = generic_file_llseek, |
562 | .read = generic_read_dir, | |
6f7f231e | 563 | .iterate = cramfs_readdir, |
1da177e4 LT |
564 | }; |
565 | ||
754661f1 | 566 | static const struct inode_operations cramfs_dir_inode_operations = { |
1da177e4 LT |
567 | .lookup = cramfs_lookup, |
568 | }; | |
569 | ||
ee9b6d61 | 570 | static const struct super_operations cramfs_ops = { |
1da177e4 LT |
571 | .remount_fs = cramfs_remount, |
572 | .statfs = cramfs_statfs, | |
573 | }; | |
574 | ||
152a0836 AV |
575 | static struct dentry *cramfs_mount(struct file_system_type *fs_type, |
576 | int flags, const char *dev_name, void *data) | |
1da177e4 | 577 | { |
152a0836 | 578 | return mount_bdev(fs_type, flags, dev_name, data, cramfs_fill_super); |
1da177e4 LT |
579 | } |
580 | ||
581 | static struct file_system_type cramfs_fs_type = { | |
582 | .owner = THIS_MODULE, | |
583 | .name = "cramfs", | |
152a0836 | 584 | .mount = cramfs_mount, |
2309fb8e | 585 | .kill_sb = cramfs_kill_sb, |
1da177e4 LT |
586 | .fs_flags = FS_REQUIRES_DEV, |
587 | }; | |
7f78e035 | 588 | MODULE_ALIAS_FS("cramfs"); |
1da177e4 LT |
589 | |
590 | static int __init init_cramfs_fs(void) | |
591 | { | |
50d44ed0 AD |
592 | int rv; |
593 | ||
594 | rv = cramfs_uncompress_init(); | |
595 | if (rv < 0) | |
596 | return rv; | |
597 | rv = register_filesystem(&cramfs_fs_type); | |
598 | if (rv < 0) | |
599 | cramfs_uncompress_exit(); | |
600 | return rv; | |
1da177e4 LT |
601 | } |
602 | ||
603 | static void __exit exit_cramfs_fs(void) | |
604 | { | |
605 | cramfs_uncompress_exit(); | |
606 | unregister_filesystem(&cramfs_fs_type); | |
607 | } | |
608 | ||
609 | module_init(init_cramfs_fs) | |
610 | module_exit(exit_cramfs_fs) | |
611 | MODULE_LICENSE("GPL"); |