blob: e501ac3a49ff7380a1bd2644ecc8abc3f648ce64 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
20#include <linux/cramfs_fs.h>
21#include <linux/slab.h>
22#include <linux/cramfs_fs_sb.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/vfs.h>
Ingo Molnar353ab6e2006-03-26 01:37:12 -080024#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26#include <asm/uaccess.h>
27
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -080028static const struct super_operations cramfs_ops;
Arjan van de Ven754661f2007-02-12 00:55:38 -080029static const struct inode_operations cramfs_dir_inode_operations;
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080030static const struct file_operations cramfs_directory_operations;
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070031static const struct address_space_operations cramfs_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Ingo Molnar353ab6e2006-03-26 01:37:12 -080033static DEFINE_MUTEX(read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35
Stefani Seibold6f772fe2011-01-12 17:01:10 -080036/* These macros may change in future, to provide better st_ino semantics. */
Linus Torvalds1da177e2005-04-16 15:20:36 -070037#define OFFSET(x) ((x)->i_ino)
38
Al Viro0577d1b2011-07-17 19:04:14 -040039static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070040{
Stefani Seibold6f772fe2011-01-12 17:01:10 -080041 if (!cino->offset)
42 return offset + 1;
43 if (!cino->size)
44 return offset + 1;
45
46 /*
47 * The file mode test fixes buggy mkcramfs implementations where
48 * cramfs_inode->offset is set to a non zero value for entries
49 * which did not contain data, like devices node and fifos.
50 */
51 switch (cino->mode & S_IFMT) {
52 case S_IFREG:
53 case S_IFDIR:
54 case S_IFLNK:
55 return cino->offset << 2;
56 default:
57 break;
58 }
59 return offset + 1;
60}
61
62static struct inode *get_cramfs_inode(struct super_block *sb,
Al Viro0577d1b2011-07-17 19:04:14 -040063 const struct cramfs_inode *cramfs_inode, unsigned int offset)
Stefani Seibold6f772fe2011-01-12 17:01:10 -080064{
65 struct inode *inode;
Al Viro77b8a752010-06-04 21:19:01 -040066 static struct timespec zerotime;
Stefani Seibold6f772fe2011-01-12 17:01:10 -080067
68 inode = iget_locked(sb, cramino(cramfs_inode, offset));
69 if (!inode)
70 return ERR_PTR(-ENOMEM);
71 if (!(inode->i_state & I_NEW))
72 return inode;
73
74 switch (cramfs_inode->mode & S_IFMT) {
75 case S_IFREG:
76 inode->i_fop = &generic_ro_fops;
77 inode->i_data.a_ops = &cramfs_aops;
78 break;
79 case S_IFDIR:
80 inode->i_op = &cramfs_dir_inode_operations;
81 inode->i_fop = &cramfs_directory_operations;
82 break;
83 case S_IFLNK:
84 inode->i_op = &page_symlink_inode_operations;
85 inode->i_data.a_ops = &cramfs_aops;
86 break;
87 default:
88 init_special_inode(inode, cramfs_inode->mode,
89 old_decode_dev(cramfs_inode->size));
90 }
91
Al Viro77b8a752010-06-04 21:19:01 -040092 inode->i_mode = cramfs_inode->mode;
Eric W. Biedermana7d9cfe2012-02-10 11:06:08 -080093 i_uid_write(inode, cramfs_inode->uid);
94 i_gid_write(inode, cramfs_inode->gid);
Stefani Seibold6f772fe2011-01-12 17:01:10 -080095
96 /* if the lower 2 bits are zero, the inode contains data */
97 if (!(inode->i_ino & 3)) {
98 inode->i_size = cramfs_inode->size;
99 inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
100 }
101
Al Viro77b8a752010-06-04 21:19:01 -0400102 /* Struct copy intentional */
103 inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
104 /* inode->i_nlink is left 1 - arguably wrong for directories,
105 but it's the best we can do without reading the directory
106 contents. 1 yields the right result in GNU find, even
107 without -noleaf option. */
Dave Johnsona97c9bf2005-09-06 15:17:40 -0700108
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800109 unlock_new_inode(inode);
110
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 return inode;
112}
113
114/*
115 * We have our own block cache: don't fill up the buffer cache
116 * with the rom-image, because the way the filesystem is set
117 * up the accesses should be fairly regular and cached in the
118 * page cache and dentry tree anyway..
119 *
120 * This also acts as a way to guarantee contiguous areas of up to
121 * BLKS_PER_BUF*PAGE_CACHE_SIZE, so that the caller doesn't need to
122 * worry about end-of-buffer issues even when decompressing a full
123 * page cache.
124 */
125#define READ_BUFFERS (2)
126/* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */
127#define NEXT_BUFFER(_ix) ((_ix) ^ 1)
128
129/*
130 * BLKS_PER_BUF_SHIFT should be at least 2 to allow for "compressed"
131 * data that takes up more space than the original and with unlucky
132 * alignment.
133 */
134#define BLKS_PER_BUF_SHIFT (2)
135#define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT)
136#define BUFFER_SIZE (BLKS_PER_BUF*PAGE_CACHE_SIZE)
137
138static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE];
139static unsigned buffer_blocknr[READ_BUFFERS];
140static struct super_block * buffer_dev[READ_BUFFERS];
141static int next_buffer;
142
143/*
144 * Returns a pointer to a buffer containing at least LEN bytes of
145 * filesystem starting at byte offset OFFSET into the filesystem.
146 */
147static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned int len)
148{
149 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
150 struct page *pages[BLKS_PER_BUF];
Andi Drebes6bbfb072007-10-18 03:06:54 -0700151 unsigned i, blocknr, buffer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 unsigned long devsize;
153 char *data;
154
155 if (!len)
156 return NULL;
157 blocknr = offset >> PAGE_CACHE_SHIFT;
158 offset &= PAGE_CACHE_SIZE - 1;
159
160 /* Check if an existing buffer already has the data.. */
161 for (i = 0; i < READ_BUFFERS; i++) {
162 unsigned int blk_offset;
163
164 if (buffer_dev[i] != sb)
165 continue;
166 if (blocknr < buffer_blocknr[i])
167 continue;
168 blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_SHIFT;
169 blk_offset += offset;
170 if (blk_offset + len > BUFFER_SIZE)
171 continue;
172 return read_buffers[i] + blk_offset;
173 }
174
175 devsize = mapping->host->i_size >> PAGE_CACHE_SHIFT;
176
177 /* Ok, read in BLKS_PER_BUF pages completely first. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 for (i = 0; i < BLKS_PER_BUF; i++) {
179 struct page *page = NULL;
180
181 if (blocknr + i < devsize) {
Nick Piggin6fe69002007-05-06 14:49:04 -0700182 page = read_mapping_page_async(mapping, blocknr + i,
183 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 /* synchronous error? */
185 if (IS_ERR(page))
186 page = NULL;
187 }
188 pages[i] = page;
189 }
190
191 for (i = 0; i < BLKS_PER_BUF; i++) {
192 struct page *page = pages[i];
193 if (page) {
194 wait_on_page_locked(page);
195 if (!PageUptodate(page)) {
196 /* asynchronous error */
197 page_cache_release(page);
198 pages[i] = NULL;
199 }
200 }
201 }
202
203 buffer = next_buffer;
204 next_buffer = NEXT_BUFFER(buffer);
205 buffer_blocknr[buffer] = blocknr;
206 buffer_dev[buffer] = sb;
207
208 data = read_buffers[buffer];
209 for (i = 0; i < BLKS_PER_BUF; i++) {
210 struct page *page = pages[i];
211 if (page) {
212 memcpy(data, kmap(page), PAGE_CACHE_SIZE);
213 kunmap(page);
214 page_cache_release(page);
215 } else
216 memset(data, 0, PAGE_CACHE_SIZE);
217 data += PAGE_CACHE_SIZE;
218 }
219 return read_buffers[buffer] + offset;
220}
221
222static void cramfs_put_super(struct super_block *sb)
223{
224 kfree(sb->s_fs_info);
225 sb->s_fs_info = NULL;
226}
227
228static int cramfs_remount(struct super_block *sb, int *flags, char *data)
229{
230 *flags |= MS_RDONLY;
231 return 0;
232}
233
234static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
235{
236 int i;
237 struct cramfs_super super;
238 unsigned long root_offset;
239 struct cramfs_sb_info *sbi;
240 struct inode *root;
241
242 sb->s_flags |= MS_RDONLY;
243
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -0700244 sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 if (!sbi)
246 return -ENOMEM;
247 sb->s_fs_info = sbi;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
249 /* Invalidate the read buffers on mount: think disk change.. */
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800250 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 for (i = 0; i < READ_BUFFERS; i++)
252 buffer_blocknr[i] = -1;
253
254 /* Read the first block and get the superblock from it */
255 memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super));
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800256 mutex_unlock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 /* Do sanity checks on the superblock */
259 if (super.magic != CRAMFS_MAGIC) {
Masanari Iida0cc785e2012-02-11 21:35:12 +0900260 /* check for wrong endianness */
Andi Drebesac8d35c2007-10-16 23:27:12 -0700261 if (super.magic == CRAMFS_MAGIC_WEND) {
262 if (!silent)
Masanari Iida0cc785e2012-02-11 21:35:12 +0900263 printk(KERN_ERR "cramfs: wrong endianness\n");
Andi Drebesac8d35c2007-10-16 23:27:12 -0700264 goto out;
265 }
266
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 /* check at 512 byte offset */
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800268 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super));
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800270 mutex_unlock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 if (super.magic != CRAMFS_MAGIC) {
Andi Drebesac8d35c2007-10-16 23:27:12 -0700272 if (super.magic == CRAMFS_MAGIC_WEND && !silent)
Masanari Iida0cc785e2012-02-11 21:35:12 +0900273 printk(KERN_ERR "cramfs: wrong endianness\n");
Andi Drebesac8d35c2007-10-16 23:27:12 -0700274 else if (!silent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 printk(KERN_ERR "cramfs: wrong magic\n");
276 goto out;
277 }
278 }
279
280 /* get feature flags first */
281 if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
282 printk(KERN_ERR "cramfs: unsupported filesystem features\n");
283 goto out;
284 }
285
286 /* Check that the root inode is in a sane state */
287 if (!S_ISDIR(super.root.mode)) {
288 printk(KERN_ERR "cramfs: root is not a directory\n");
289 goto out;
290 }
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800291 /* correct strange, hard-coded permissions of mkcramfs */
292 super.root.mode |= (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 root_offset = super.root.offset << 2;
295 if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) {
296 sbi->size=super.size;
297 sbi->blocks=super.fsid.blocks;
298 sbi->files=super.fsid.files;
299 } else {
300 sbi->size=1<<28;
301 sbi->blocks=0;
302 sbi->files=0;
303 }
304 sbi->magic=super.magic;
305 sbi->flags=super.flags;
306 if (root_offset == 0)
307 printk(KERN_INFO "cramfs: empty filesystem");
308 else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
309 ((root_offset != sizeof(struct cramfs_super)) &&
310 (root_offset != 512 + sizeof(struct cramfs_super))))
311 {
312 printk(KERN_ERR "cramfs: bad root offset %lu\n", root_offset);
313 goto out;
314 }
315
316 /* Set it all up.. */
317 sb->s_op = &cramfs_ops;
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800318 root = get_cramfs_inode(sb, &super.root, 0);
Al Viro0577d1b2011-07-17 19:04:14 -0400319 if (IS_ERR(root))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 goto out;
Al Viro48fde702012-01-08 22:15:13 -0500321 sb->s_root = d_make_root(root);
322 if (!sb->s_root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 return 0;
325out:
326 kfree(sbi);
327 sb->s_fs_info = NULL;
328 return -EINVAL;
329}
330
David Howells726c3342006-06-23 02:02:58 -0700331static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332{
David Howells726c3342006-06-23 02:02:58 -0700333 struct super_block *sb = dentry->d_sb;
Coly Li94ea77a2009-04-02 16:59:33 -0700334 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
David Howells726c3342006-06-23 02:02:58 -0700335
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 buf->f_type = CRAMFS_MAGIC;
337 buf->f_bsize = PAGE_CACHE_SIZE;
338 buf->f_blocks = CRAMFS_SB(sb)->blocks;
339 buf->f_bfree = 0;
340 buf->f_bavail = 0;
341 buf->f_files = CRAMFS_SB(sb)->files;
342 buf->f_ffree = 0;
Coly Li94ea77a2009-04-02 16:59:33 -0700343 buf->f_fsid.val[0] = (u32)id;
344 buf->f_fsid.val[1] = (u32)(id >> 32);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 buf->f_namelen = CRAMFS_MAXPATHLEN;
346 return 0;
347}
348
349/*
350 * Read a cramfs directory entry.
351 */
Al Viro6f7f2312013-05-17 18:02:17 -0400352static int cramfs_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353{
Al Viro6f7f2312013-05-17 18:02:17 -0400354 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 struct super_block *sb = inode->i_sb;
356 char *buf;
357 unsigned int offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358
359 /* Offset within the thing. */
Al Viro6f7f2312013-05-17 18:02:17 -0400360 if (ctx->pos >= inode->i_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 return 0;
Al Viro6f7f2312013-05-17 18:02:17 -0400362 offset = ctx->pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 /* Directory entries are always 4-byte aligned */
364 if (offset & 3)
365 return -EINVAL;
366
Andi Drebes4176ed52007-10-18 03:06:55 -0700367 buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 if (!buf)
369 return -ENOMEM;
370
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 while (offset < inode->i_size) {
372 struct cramfs_inode *de;
373 unsigned long nextoffset;
374 char *name;
375 ino_t ino;
Al Viro175a4eb2011-07-26 03:30:54 -0400376 umode_t mode;
Al Viro6f7f2312013-05-17 18:02:17 -0400377 int namelen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800379 mutex_lock(&read_mutex);
Andi Drebes4176ed52007-10-18 03:06:55 -0700380 de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 name = (char *)(de+1);
382
383 /*
384 * Namelengths on disk are shifted by two
385 * and the name padded out to 4-byte boundaries
386 * with zeroes.
387 */
388 namelen = de->namelen << 2;
389 memcpy(buf, name, namelen);
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800390 ino = cramino(de, OFFSET(inode) + offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 mode = de->mode;
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800392 mutex_unlock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 nextoffset = offset + sizeof(*de) + namelen;
394 for (;;) {
395 if (!namelen) {
396 kfree(buf);
397 return -EIO;
398 }
399 if (buf[namelen-1])
400 break;
401 namelen--;
402 }
Al Viro6f7f2312013-05-17 18:02:17 -0400403 if (!dir_emit(ctx, buf, namelen, ino, mode >> 12))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 break;
405
Al Viro6f7f2312013-05-17 18:02:17 -0400406 ctx->pos = offset = nextoffset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 }
408 kfree(buf);
409 return 0;
410}
411
412/*
413 * Lookup and fill in the inode data..
414 */
Al Viro00cd8dd2012-06-10 17:13:09 -0400415static struct dentry * cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416{
417 unsigned int offset = 0;
Al Viro0577d1b2011-07-17 19:04:14 -0400418 struct inode *inode = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 int sorted;
420
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800421 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS;
423 while (offset < dir->i_size) {
424 struct cramfs_inode *de;
425 char *name;
426 int namelen, retval;
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800427 int dir_off = OFFSET(dir) + offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800429 de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 name = (char *)(de+1);
431
432 /* Try to take advantage of sorted directories */
433 if (sorted && (dentry->d_name.name[0] < name[0]))
434 break;
435
436 namelen = de->namelen << 2;
437 offset += sizeof(*de) + namelen;
438
439 /* Quick check that the name is roughly the right length */
440 if (((dentry->d_name.len + 3) & ~3) != namelen)
441 continue;
442
443 for (;;) {
444 if (!namelen) {
Al Viro0577d1b2011-07-17 19:04:14 -0400445 inode = ERR_PTR(-EIO);
446 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 }
448 if (name[namelen-1])
449 break;
450 namelen--;
451 }
452 if (namelen != dentry->d_name.len)
453 continue;
454 retval = memcmp(dentry->d_name.name, name, namelen);
455 if (retval > 0)
456 continue;
457 if (!retval) {
Al Viro0577d1b2011-07-17 19:04:14 -0400458 inode = get_cramfs_inode(dir->i_sb, de, dir_off);
459 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 }
461 /* else (retval < 0) */
462 if (sorted)
463 break;
464 }
Al Viro0577d1b2011-07-17 19:04:14 -0400465out:
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800466 mutex_unlock(&read_mutex);
Al Viro0577d1b2011-07-17 19:04:14 -0400467 if (IS_ERR(inode))
468 return ERR_CAST(inode);
469 d_add(dentry, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 return NULL;
471}
472
473static int cramfs_readpage(struct file *file, struct page * page)
474{
475 struct inode *inode = page->mapping->host;
David VomLehn98310e52009-04-02 16:59:15 -0700476 u32 maxblock;
477 int bytes_filled;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 void *pgdata;
479
480 maxblock = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
481 bytes_filled = 0;
David VomLehn98310e52009-04-02 16:59:15 -0700482 pgdata = kmap(page);
483
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 if (page->index < maxblock) {
485 struct super_block *sb = inode->i_sb;
486 u32 blkptr_offset = OFFSET(inode) + page->index*4;
487 u32 start_offset, compr_len;
488
489 start_offset = OFFSET(inode) + maxblock*4;
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800490 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 if (page->index)
David VomLehn98310e52009-04-02 16:59:15 -0700492 start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4,
493 4);
494 compr_len = (*(u32 *) cramfs_read(sb, blkptr_offset, 4) -
495 start_offset);
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800496 mutex_unlock(&read_mutex);
David VomLehn98310e52009-04-02 16:59:15 -0700497
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 if (compr_len == 0)
499 ; /* hole */
David VomLehn98310e52009-04-02 16:59:15 -0700500 else if (unlikely(compr_len > (PAGE_CACHE_SIZE << 1))) {
501 pr_err("cramfs: bad compressed blocksize %u\n",
502 compr_len);
503 goto err;
504 } else {
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800505 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 bytes_filled = cramfs_uncompress_block(pgdata,
507 PAGE_CACHE_SIZE,
508 cramfs_read(sb, start_offset, compr_len),
509 compr_len);
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800510 mutex_unlock(&read_mutex);
David VomLehn98310e52009-04-02 16:59:15 -0700511 if (unlikely(bytes_filled < 0))
512 goto err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 }
David VomLehn98310e52009-04-02 16:59:15 -0700514 }
515
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 flush_dcache_page(page);
David VomLehn98310e52009-04-02 16:59:15 -0700518 kunmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 SetPageUptodate(page);
520 unlock_page(page);
521 return 0;
David VomLehn98310e52009-04-02 16:59:15 -0700522
523err:
524 kunmap(page);
525 ClearPageUptodate(page);
526 SetPageError(page);
527 unlock_page(page);
528 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529}
530
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700531static const struct address_space_operations cramfs_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 .readpage = cramfs_readpage
533};
534
535/*
536 * Our operations:
537 */
538
539/*
540 * A directory can only readdir
541 */
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800542static const struct file_operations cramfs_directory_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 .llseek = generic_file_llseek,
544 .read = generic_read_dir,
Al Viro6f7f2312013-05-17 18:02:17 -0400545 .iterate = cramfs_readdir,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546};
547
Arjan van de Ven754661f2007-02-12 00:55:38 -0800548static const struct inode_operations cramfs_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 .lookup = cramfs_lookup,
550};
551
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800552static const struct super_operations cramfs_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 .put_super = cramfs_put_super,
554 .remount_fs = cramfs_remount,
555 .statfs = cramfs_statfs,
556};
557
Al Viro152a0832010-07-25 00:46:55 +0400558static struct dentry *cramfs_mount(struct file_system_type *fs_type,
559 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560{
Al Viro152a0832010-07-25 00:46:55 +0400561 return mount_bdev(fs_type, flags, dev_name, data, cramfs_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562}
563
564static struct file_system_type cramfs_fs_type = {
565 .owner = THIS_MODULE,
566 .name = "cramfs",
Al Viro152a0832010-07-25 00:46:55 +0400567 .mount = cramfs_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 .kill_sb = kill_block_super,
569 .fs_flags = FS_REQUIRES_DEV,
570};
Eric W. Biederman7f78e032013-03-02 19:39:14 -0800571MODULE_ALIAS_FS("cramfs");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572
573static int __init init_cramfs_fs(void)
574{
Alexey Dobriyan50d44ed2006-09-29 02:01:04 -0700575 int rv;
576
577 rv = cramfs_uncompress_init();
578 if (rv < 0)
579 return rv;
580 rv = register_filesystem(&cramfs_fs_type);
581 if (rv < 0)
582 cramfs_uncompress_exit();
583 return rv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584}
585
586static void __exit exit_cramfs_fs(void)
587{
588 cramfs_uncompress_exit();
589 unregister_filesystem(&cramfs_fs_type);
590}
591
592module_init(init_cramfs_fs)
593module_exit(exit_cramfs_fs)
594MODULE_LICENSE("GPL");