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 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/pagemap.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/string.h> | |
19 | #include <linux/blkdev.h> | |
1da177e4 | 20 | #include <linux/slab.h> |
1da177e4 | 21 | #include <linux/vfs.h> |
353ab6e9 | 22 | #include <linux/mutex.h> |
f7f4f4dd | 23 | #include <uapi/linux/cramfs_fs.h> |
1da177e4 LT |
24 | #include <asm/uaccess.h> |
25 | ||
f7f4f4dd AV |
26 | #include "internal.h" |
27 | ||
28 | /* | |
29 | * cramfs super-block data in memory | |
30 | */ | |
31 | struct cramfs_sb_info { | |
32 | unsigned long magic; | |
33 | unsigned long size; | |
34 | unsigned long blocks; | |
35 | unsigned long files; | |
36 | unsigned long flags; | |
37 | }; | |
38 | ||
39 | static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb) | |
40 | { | |
41 | return sb->s_fs_info; | |
42 | } | |
43 | ||
ee9b6d61 | 44 | static const struct super_operations cramfs_ops; |
754661f1 | 45 | static const struct inode_operations cramfs_dir_inode_operations; |
4b6f5d20 | 46 | static const struct file_operations cramfs_directory_operations; |
f5e54d6e | 47 | static const struct address_space_operations cramfs_aops; |
1da177e4 | 48 | |
353ab6e9 | 49 | static DEFINE_MUTEX(read_mutex); |
1da177e4 LT |
50 | |
51 | ||
6f772fe6 | 52 | /* These macros may change in future, to provide better st_ino semantics. */ |
1da177e4 LT |
53 | #define OFFSET(x) ((x)->i_ino) |
54 | ||
0577d1ba | 55 | static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset) |
a97c9bf3 | 56 | { |
6f772fe6 SS |
57 | if (!cino->offset) |
58 | return offset + 1; | |
59 | if (!cino->size) | |
60 | return offset + 1; | |
61 | ||
62 | /* | |
63 | * The file mode test fixes buggy mkcramfs implementations where | |
64 | * cramfs_inode->offset is set to a non zero value for entries | |
65 | * which did not contain data, like devices node and fifos. | |
66 | */ | |
67 | switch (cino->mode & S_IFMT) { | |
68 | case S_IFREG: | |
69 | case S_IFDIR: | |
70 | case S_IFLNK: | |
71 | return cino->offset << 2; | |
72 | default: | |
73 | break; | |
74 | } | |
75 | return offset + 1; | |
76 | } | |
77 | ||
78 | static struct inode *get_cramfs_inode(struct super_block *sb, | |
0577d1ba | 79 | const struct cramfs_inode *cramfs_inode, unsigned int offset) |
6f772fe6 SS |
80 | { |
81 | struct inode *inode; | |
77b8a75f | 82 | static struct timespec zerotime; |
6f772fe6 SS |
83 | |
84 | inode = iget_locked(sb, cramino(cramfs_inode, offset)); | |
85 | if (!inode) | |
86 | return ERR_PTR(-ENOMEM); | |
87 | if (!(inode->i_state & I_NEW)) | |
88 | return inode; | |
89 | ||
90 | switch (cramfs_inode->mode & S_IFMT) { | |
91 | case S_IFREG: | |
92 | inode->i_fop = &generic_ro_fops; | |
93 | inode->i_data.a_ops = &cramfs_aops; | |
94 | break; | |
95 | case S_IFDIR: | |
96 | inode->i_op = &cramfs_dir_inode_operations; | |
97 | inode->i_fop = &cramfs_directory_operations; | |
98 | break; | |
99 | case S_IFLNK: | |
100 | inode->i_op = &page_symlink_inode_operations; | |
101 | inode->i_data.a_ops = &cramfs_aops; | |
102 | break; | |
103 | default: | |
104 | init_special_inode(inode, cramfs_inode->mode, | |
105 | old_decode_dev(cramfs_inode->size)); | |
106 | } | |
107 | ||
77b8a75f | 108 | inode->i_mode = cramfs_inode->mode; |
a7d9cfe9 EB |
109 | i_uid_write(inode, cramfs_inode->uid); |
110 | i_gid_write(inode, cramfs_inode->gid); | |
6f772fe6 SS |
111 | |
112 | /* if the lower 2 bits are zero, the inode contains data */ | |
113 | if (!(inode->i_ino & 3)) { | |
114 | inode->i_size = cramfs_inode->size; | |
115 | inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1; | |
116 | } | |
117 | ||
77b8a75f AV |
118 | /* Struct copy intentional */ |
119 | inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime; | |
120 | /* inode->i_nlink is left 1 - arguably wrong for directories, | |
121 | but it's the best we can do without reading the directory | |
122 | contents. 1 yields the right result in GNU find, even | |
123 | without -noleaf option. */ | |
a97c9bf3 | 124 | |
6f772fe6 SS |
125 | unlock_new_inode(inode); |
126 | ||
1da177e4 LT |
127 | return inode; |
128 | } | |
129 | ||
130 | /* | |
131 | * We have our own block cache: don't fill up the buffer cache | |
132 | * with the rom-image, because the way the filesystem is set | |
133 | * up the accesses should be fairly regular and cached in the | |
134 | * page cache and dentry tree anyway.. | |
135 | * | |
136 | * This also acts as a way to guarantee contiguous areas of up to | |
137 | * BLKS_PER_BUF*PAGE_CACHE_SIZE, so that the caller doesn't need to | |
138 | * worry about end-of-buffer issues even when decompressing a full | |
139 | * page cache. | |
140 | */ | |
141 | #define READ_BUFFERS (2) | |
142 | /* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */ | |
143 | #define NEXT_BUFFER(_ix) ((_ix) ^ 1) | |
144 | ||
145 | /* | |
146 | * BLKS_PER_BUF_SHIFT should be at least 2 to allow for "compressed" | |
147 | * data that takes up more space than the original and with unlucky | |
148 | * alignment. | |
149 | */ | |
150 | #define BLKS_PER_BUF_SHIFT (2) | |
151 | #define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT) | |
152 | #define BUFFER_SIZE (BLKS_PER_BUF*PAGE_CACHE_SIZE) | |
153 | ||
154 | static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE]; | |
155 | static unsigned buffer_blocknr[READ_BUFFERS]; | |
156 | static struct super_block * buffer_dev[READ_BUFFERS]; | |
157 | static int next_buffer; | |
158 | ||
159 | /* | |
160 | * Returns a pointer to a buffer containing at least LEN bytes of | |
161 | * filesystem starting at byte offset OFFSET into the filesystem. | |
162 | */ | |
163 | static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned int len) | |
164 | { | |
165 | struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; | |
166 | struct page *pages[BLKS_PER_BUF]; | |
6bbfb077 | 167 | unsigned i, blocknr, buffer; |
1da177e4 LT |
168 | unsigned long devsize; |
169 | char *data; | |
170 | ||
171 | if (!len) | |
172 | return NULL; | |
173 | blocknr = offset >> PAGE_CACHE_SHIFT; | |
174 | offset &= PAGE_CACHE_SIZE - 1; | |
175 | ||
176 | /* Check if an existing buffer already has the data.. */ | |
177 | for (i = 0; i < READ_BUFFERS; i++) { | |
178 | unsigned int blk_offset; | |
179 | ||
180 | if (buffer_dev[i] != sb) | |
181 | continue; | |
182 | if (blocknr < buffer_blocknr[i]) | |
183 | continue; | |
184 | blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_SHIFT; | |
185 | blk_offset += offset; | |
186 | if (blk_offset + len > BUFFER_SIZE) | |
187 | continue; | |
188 | return read_buffers[i] + blk_offset; | |
189 | } | |
190 | ||
191 | devsize = mapping->host->i_size >> PAGE_CACHE_SHIFT; | |
192 | ||
193 | /* Ok, read in BLKS_PER_BUF pages completely first. */ | |
1da177e4 LT |
194 | for (i = 0; i < BLKS_PER_BUF; i++) { |
195 | struct page *page = NULL; | |
196 | ||
197 | if (blocknr + i < devsize) { | |
67f9fd91 | 198 | page = read_mapping_page(mapping, blocknr + i, NULL); |
1da177e4 LT |
199 | /* synchronous error? */ |
200 | if (IS_ERR(page)) | |
201 | page = NULL; | |
202 | } | |
203 | pages[i] = page; | |
204 | } | |
205 | ||
206 | for (i = 0; i < BLKS_PER_BUF; i++) { | |
207 | struct page *page = pages[i]; | |
208 | if (page) { | |
209 | wait_on_page_locked(page); | |
210 | if (!PageUptodate(page)) { | |
211 | /* asynchronous error */ | |
212 | page_cache_release(page); | |
213 | pages[i] = NULL; | |
214 | } | |
215 | } | |
216 | } | |
217 | ||
218 | buffer = next_buffer; | |
219 | next_buffer = NEXT_BUFFER(buffer); | |
220 | buffer_blocknr[buffer] = blocknr; | |
221 | buffer_dev[buffer] = sb; | |
222 | ||
223 | data = read_buffers[buffer]; | |
224 | for (i = 0; i < BLKS_PER_BUF; i++) { | |
225 | struct page *page = pages[i]; | |
226 | if (page) { | |
227 | memcpy(data, kmap(page), PAGE_CACHE_SIZE); | |
228 | kunmap(page); | |
229 | page_cache_release(page); | |
230 | } else | |
231 | memset(data, 0, PAGE_CACHE_SIZE); | |
232 | data += PAGE_CACHE_SIZE; | |
233 | } | |
234 | return read_buffers[buffer] + offset; | |
235 | } | |
236 | ||
2309fb8e | 237 | static void cramfs_kill_sb(struct super_block *sb) |
1da177e4 | 238 | { |
f7f4f4dd | 239 | struct cramfs_sb_info *sbi = CRAMFS_SB(sb); |
2309fb8e AV |
240 | kill_block_super(sb); |
241 | kfree(sbi); | |
1da177e4 LT |
242 | } |
243 | ||
244 | static int cramfs_remount(struct super_block *sb, int *flags, char *data) | |
245 | { | |
02b9984d | 246 | sync_filesystem(sb); |
1da177e4 LT |
247 | *flags |= MS_RDONLY; |
248 | return 0; | |
249 | } | |
250 | ||
251 | static int cramfs_fill_super(struct super_block *sb, void *data, int silent) | |
252 | { | |
253 | int i; | |
254 | struct cramfs_super super; | |
255 | unsigned long root_offset; | |
256 | struct cramfs_sb_info *sbi; | |
257 | struct inode *root; | |
258 | ||
259 | sb->s_flags |= MS_RDONLY; | |
260 | ||
f8314dc6 | 261 | sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL); |
1da177e4 LT |
262 | if (!sbi) |
263 | return -ENOMEM; | |
264 | sb->s_fs_info = sbi; | |
1da177e4 LT |
265 | |
266 | /* Invalidate the read buffers on mount: think disk change.. */ | |
353ab6e9 | 267 | mutex_lock(&read_mutex); |
1da177e4 LT |
268 | for (i = 0; i < READ_BUFFERS; i++) |
269 | buffer_blocknr[i] = -1; | |
270 | ||
271 | /* Read the first block and get the superblock from it */ | |
272 | memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super)); | |
353ab6e9 | 273 | mutex_unlock(&read_mutex); |
1da177e4 LT |
274 | |
275 | /* Do sanity checks on the superblock */ | |
276 | if (super.magic != CRAMFS_MAGIC) { | |
0cc785ec | 277 | /* check for wrong endianness */ |
ac8d35c5 AD |
278 | if (super.magic == CRAMFS_MAGIC_WEND) { |
279 | if (!silent) | |
0cc785ec | 280 | printk(KERN_ERR "cramfs: wrong endianness\n"); |
2309fb8e | 281 | return -EINVAL; |
ac8d35c5 AD |
282 | } |
283 | ||
1da177e4 | 284 | /* check at 512 byte offset */ |
353ab6e9 | 285 | mutex_lock(&read_mutex); |
1da177e4 | 286 | memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super)); |
353ab6e9 | 287 | mutex_unlock(&read_mutex); |
1da177e4 | 288 | if (super.magic != CRAMFS_MAGIC) { |
ac8d35c5 | 289 | if (super.magic == CRAMFS_MAGIC_WEND && !silent) |
0cc785ec | 290 | printk(KERN_ERR "cramfs: wrong endianness\n"); |
ac8d35c5 | 291 | else if (!silent) |
1da177e4 | 292 | printk(KERN_ERR "cramfs: wrong magic\n"); |
2309fb8e | 293 | return -EINVAL; |
1da177e4 LT |
294 | } |
295 | } | |
296 | ||
297 | /* get feature flags first */ | |
298 | if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) { | |
299 | printk(KERN_ERR "cramfs: unsupported filesystem features\n"); | |
2309fb8e | 300 | return -EINVAL; |
1da177e4 LT |
301 | } |
302 | ||
303 | /* Check that the root inode is in a sane state */ | |
304 | if (!S_ISDIR(super.root.mode)) { | |
305 | printk(KERN_ERR "cramfs: root is not a directory\n"); | |
2309fb8e | 306 | return -EINVAL; |
1da177e4 | 307 | } |
6f772fe6 SS |
308 | /* correct strange, hard-coded permissions of mkcramfs */ |
309 | super.root.mode |= (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH); | |
310 | ||
1da177e4 LT |
311 | root_offset = super.root.offset << 2; |
312 | if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) { | |
313 | sbi->size=super.size; | |
314 | sbi->blocks=super.fsid.blocks; | |
315 | sbi->files=super.fsid.files; | |
316 | } else { | |
317 | sbi->size=1<<28; | |
318 | sbi->blocks=0; | |
319 | sbi->files=0; | |
320 | } | |
321 | sbi->magic=super.magic; | |
322 | sbi->flags=super.flags; | |
323 | if (root_offset == 0) | |
324 | printk(KERN_INFO "cramfs: empty filesystem"); | |
325 | else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) && | |
326 | ((root_offset != sizeof(struct cramfs_super)) && | |
327 | (root_offset != 512 + sizeof(struct cramfs_super)))) | |
328 | { | |
329 | printk(KERN_ERR "cramfs: bad root offset %lu\n", root_offset); | |
2309fb8e | 330 | return -EINVAL; |
1da177e4 LT |
331 | } |
332 | ||
333 | /* Set it all up.. */ | |
334 | sb->s_op = &cramfs_ops; | |
6f772fe6 | 335 | root = get_cramfs_inode(sb, &super.root, 0); |
0577d1ba | 336 | if (IS_ERR(root)) |
2309fb8e | 337 | return PTR_ERR(root); |
48fde701 AV |
338 | sb->s_root = d_make_root(root); |
339 | if (!sb->s_root) | |
2309fb8e | 340 | return -ENOMEM; |
1da177e4 | 341 | return 0; |
1da177e4 LT |
342 | } |
343 | ||
726c3342 | 344 | static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 345 | { |
726c3342 | 346 | struct super_block *sb = dentry->d_sb; |
94ea77ac | 347 | u64 id = huge_encode_dev(sb->s_bdev->bd_dev); |
726c3342 | 348 | |
1da177e4 LT |
349 | buf->f_type = CRAMFS_MAGIC; |
350 | buf->f_bsize = PAGE_CACHE_SIZE; | |
351 | buf->f_blocks = CRAMFS_SB(sb)->blocks; | |
352 | buf->f_bfree = 0; | |
353 | buf->f_bavail = 0; | |
354 | buf->f_files = CRAMFS_SB(sb)->files; | |
355 | buf->f_ffree = 0; | |
94ea77ac CL |
356 | buf->f_fsid.val[0] = (u32)id; |
357 | buf->f_fsid.val[1] = (u32)(id >> 32); | |
1da177e4 LT |
358 | buf->f_namelen = CRAMFS_MAXPATHLEN; |
359 | return 0; | |
360 | } | |
361 | ||
362 | /* | |
363 | * Read a cramfs directory entry. | |
364 | */ | |
6f7f231e | 365 | static int cramfs_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 366 | { |
6f7f231e | 367 | struct inode *inode = file_inode(file); |
1da177e4 LT |
368 | struct super_block *sb = inode->i_sb; |
369 | char *buf; | |
370 | unsigned int offset; | |
1da177e4 LT |
371 | |
372 | /* Offset within the thing. */ | |
6f7f231e | 373 | if (ctx->pos >= inode->i_size) |
1da177e4 | 374 | return 0; |
6f7f231e | 375 | offset = ctx->pos; |
1da177e4 LT |
376 | /* Directory entries are always 4-byte aligned */ |
377 | if (offset & 3) | |
378 | return -EINVAL; | |
379 | ||
4176ed59 | 380 | buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL); |
1da177e4 LT |
381 | if (!buf) |
382 | return -ENOMEM; | |
383 | ||
1da177e4 LT |
384 | while (offset < inode->i_size) { |
385 | struct cramfs_inode *de; | |
386 | unsigned long nextoffset; | |
387 | char *name; | |
388 | ino_t ino; | |
175a4eb7 | 389 | umode_t mode; |
6f7f231e | 390 | int namelen; |
1da177e4 | 391 | |
353ab6e9 | 392 | mutex_lock(&read_mutex); |
4176ed59 | 393 | de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN); |
1da177e4 LT |
394 | name = (char *)(de+1); |
395 | ||
396 | /* | |
397 | * Namelengths on disk are shifted by two | |
398 | * and the name padded out to 4-byte boundaries | |
399 | * with zeroes. | |
400 | */ | |
401 | namelen = de->namelen << 2; | |
402 | memcpy(buf, name, namelen); | |
6f772fe6 | 403 | ino = cramino(de, OFFSET(inode) + offset); |
1da177e4 | 404 | mode = de->mode; |
353ab6e9 | 405 | mutex_unlock(&read_mutex); |
1da177e4 LT |
406 | nextoffset = offset + sizeof(*de) + namelen; |
407 | for (;;) { | |
408 | if (!namelen) { | |
409 | kfree(buf); | |
410 | return -EIO; | |
411 | } | |
412 | if (buf[namelen-1]) | |
413 | break; | |
414 | namelen--; | |
415 | } | |
6f7f231e | 416 | if (!dir_emit(ctx, buf, namelen, ino, mode >> 12)) |
1da177e4 LT |
417 | break; |
418 | ||
6f7f231e | 419 | ctx->pos = offset = nextoffset; |
1da177e4 LT |
420 | } |
421 | kfree(buf); | |
422 | return 0; | |
423 | } | |
424 | ||
425 | /* | |
426 | * Lookup and fill in the inode data.. | |
427 | */ | |
00cd8dd3 | 428 | static struct dentry * cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 LT |
429 | { |
430 | unsigned int offset = 0; | |
0577d1ba | 431 | struct inode *inode = NULL; |
1da177e4 LT |
432 | int sorted; |
433 | ||
353ab6e9 | 434 | mutex_lock(&read_mutex); |
1da177e4 LT |
435 | sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS; |
436 | while (offset < dir->i_size) { | |
437 | struct cramfs_inode *de; | |
438 | char *name; | |
439 | int namelen, retval; | |
6f772fe6 | 440 | int dir_off = OFFSET(dir) + offset; |
1da177e4 | 441 | |
6f772fe6 | 442 | de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN); |
1da177e4 LT |
443 | name = (char *)(de+1); |
444 | ||
445 | /* Try to take advantage of sorted directories */ | |
446 | if (sorted && (dentry->d_name.name[0] < name[0])) | |
447 | break; | |
448 | ||
449 | namelen = de->namelen << 2; | |
450 | offset += sizeof(*de) + namelen; | |
451 | ||
452 | /* Quick check that the name is roughly the right length */ | |
453 | if (((dentry->d_name.len + 3) & ~3) != namelen) | |
454 | continue; | |
455 | ||
456 | for (;;) { | |
457 | if (!namelen) { | |
0577d1ba AV |
458 | inode = ERR_PTR(-EIO); |
459 | goto out; | |
1da177e4 LT |
460 | } |
461 | if (name[namelen-1]) | |
462 | break; | |
463 | namelen--; | |
464 | } | |
465 | if (namelen != dentry->d_name.len) | |
466 | continue; | |
467 | retval = memcmp(dentry->d_name.name, name, namelen); | |
468 | if (retval > 0) | |
469 | continue; | |
470 | if (!retval) { | |
0577d1ba AV |
471 | inode = get_cramfs_inode(dir->i_sb, de, dir_off); |
472 | break; | |
1da177e4 LT |
473 | } |
474 | /* else (retval < 0) */ | |
475 | if (sorted) | |
476 | break; | |
477 | } | |
0577d1ba | 478 | out: |
353ab6e9 | 479 | mutex_unlock(&read_mutex); |
0577d1ba AV |
480 | if (IS_ERR(inode)) |
481 | return ERR_CAST(inode); | |
482 | d_add(dentry, inode); | |
1da177e4 LT |
483 | return NULL; |
484 | } | |
485 | ||
486 | static int cramfs_readpage(struct file *file, struct page * page) | |
487 | { | |
488 | struct inode *inode = page->mapping->host; | |
98310e58 DV |
489 | u32 maxblock; |
490 | int bytes_filled; | |
1da177e4 LT |
491 | void *pgdata; |
492 | ||
493 | maxblock = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
494 | bytes_filled = 0; | |
98310e58 DV |
495 | pgdata = kmap(page); |
496 | ||
1da177e4 LT |
497 | if (page->index < maxblock) { |
498 | struct super_block *sb = inode->i_sb; | |
499 | u32 blkptr_offset = OFFSET(inode) + page->index*4; | |
500 | u32 start_offset, compr_len; | |
501 | ||
502 | start_offset = OFFSET(inode) + maxblock*4; | |
353ab6e9 | 503 | mutex_lock(&read_mutex); |
1da177e4 | 504 | if (page->index) |
98310e58 DV |
505 | start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4, |
506 | 4); | |
507 | compr_len = (*(u32 *) cramfs_read(sb, blkptr_offset, 4) - | |
508 | start_offset); | |
353ab6e9 | 509 | mutex_unlock(&read_mutex); |
98310e58 | 510 | |
1da177e4 LT |
511 | if (compr_len == 0) |
512 | ; /* hole */ | |
98310e58 DV |
513 | else if (unlikely(compr_len > (PAGE_CACHE_SIZE << 1))) { |
514 | pr_err("cramfs: bad compressed blocksize %u\n", | |
515 | compr_len); | |
516 | goto err; | |
517 | } else { | |
353ab6e9 | 518 | mutex_lock(&read_mutex); |
1da177e4 LT |
519 | bytes_filled = cramfs_uncompress_block(pgdata, |
520 | PAGE_CACHE_SIZE, | |
521 | cramfs_read(sb, start_offset, compr_len), | |
522 | compr_len); | |
353ab6e9 | 523 | mutex_unlock(&read_mutex); |
98310e58 DV |
524 | if (unlikely(bytes_filled < 0)) |
525 | goto err; | |
1da177e4 | 526 | } |
98310e58 DV |
527 | } |
528 | ||
1da177e4 | 529 | memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled); |
1da177e4 | 530 | flush_dcache_page(page); |
98310e58 | 531 | kunmap(page); |
1da177e4 LT |
532 | SetPageUptodate(page); |
533 | unlock_page(page); | |
534 | return 0; | |
98310e58 DV |
535 | |
536 | err: | |
537 | kunmap(page); | |
538 | ClearPageUptodate(page); | |
539 | SetPageError(page); | |
540 | unlock_page(page); | |
541 | return 0; | |
1da177e4 LT |
542 | } |
543 | ||
f5e54d6e | 544 | static const struct address_space_operations cramfs_aops = { |
1da177e4 LT |
545 | .readpage = cramfs_readpage |
546 | }; | |
547 | ||
548 | /* | |
549 | * Our operations: | |
550 | */ | |
551 | ||
552 | /* | |
553 | * A directory can only readdir | |
554 | */ | |
4b6f5d20 | 555 | static const struct file_operations cramfs_directory_operations = { |
1da177e4 LT |
556 | .llseek = generic_file_llseek, |
557 | .read = generic_read_dir, | |
6f7f231e | 558 | .iterate = cramfs_readdir, |
1da177e4 LT |
559 | }; |
560 | ||
754661f1 | 561 | static const struct inode_operations cramfs_dir_inode_operations = { |
1da177e4 LT |
562 | .lookup = cramfs_lookup, |
563 | }; | |
564 | ||
ee9b6d61 | 565 | static const struct super_operations cramfs_ops = { |
1da177e4 LT |
566 | .remount_fs = cramfs_remount, |
567 | .statfs = cramfs_statfs, | |
568 | }; | |
569 | ||
152a0836 AV |
570 | static struct dentry *cramfs_mount(struct file_system_type *fs_type, |
571 | int flags, const char *dev_name, void *data) | |
1da177e4 | 572 | { |
152a0836 | 573 | return mount_bdev(fs_type, flags, dev_name, data, cramfs_fill_super); |
1da177e4 LT |
574 | } |
575 | ||
576 | static struct file_system_type cramfs_fs_type = { | |
577 | .owner = THIS_MODULE, | |
578 | .name = "cramfs", | |
152a0836 | 579 | .mount = cramfs_mount, |
2309fb8e | 580 | .kill_sb = cramfs_kill_sb, |
1da177e4 LT |
581 | .fs_flags = FS_REQUIRES_DEV, |
582 | }; | |
7f78e035 | 583 | MODULE_ALIAS_FS("cramfs"); |
1da177e4 LT |
584 | |
585 | static int __init init_cramfs_fs(void) | |
586 | { | |
50d44ed0 AD |
587 | int rv; |
588 | ||
589 | rv = cramfs_uncompress_init(); | |
590 | if (rv < 0) | |
591 | return rv; | |
592 | rv = register_filesystem(&cramfs_fs_type); | |
593 | if (rv < 0) | |
594 | cramfs_uncompress_exit(); | |
595 | return rv; | |
1da177e4 LT |
596 | } |
597 | ||
598 | static void __exit exit_cramfs_fs(void) | |
599 | { | |
600 | cramfs_uncompress_exit(); | |
601 | unregister_filesystem(&cramfs_fs_type); | |
602 | } | |
603 | ||
604 | module_init(init_cramfs_fs) | |
605 | module_exit(exit_cramfs_fs) | |
606 | MODULE_LICENSE("GPL"); |