Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
| 20 | #include <linux/cramfs_fs.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/cramfs_fs_sb.h> |
| 23 | #include <linux/buffer_head.h> |
| 24 | #include <linux/vfs.h> |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 25 | #include <linux/mutex.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <asm/semaphore.h> |
| 27 | |
| 28 | #include <asm/uaccess.h> |
| 29 | |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 30 | static const struct super_operations cramfs_ops; |
Arjan van de Ven | 754661f | 2007-02-12 00:55:38 -0800 | [diff] [blame] | 31 | static const struct inode_operations cramfs_dir_inode_operations; |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 32 | static const struct file_operations cramfs_directory_operations; |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 33 | static const struct address_space_operations cramfs_aops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 35 | static DEFINE_MUTEX(read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | |
| 37 | |
| 38 | /* These two macros may change in future, to provide better st_ino |
| 39 | semantics. */ |
Dave Johnson | ff3aea0 | 2006-03-06 15:42:36 -0800 | [diff] [blame] | 40 | #define CRAMINO(x) (((x)->offset && (x)->size)?(x)->offset<<2:1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | #define OFFSET(x) ((x)->i_ino) |
| 42 | |
Dave Johnson | a97c9bf | 2005-09-06 15:17:40 -0700 | [diff] [blame] | 43 | |
| 44 | static int cramfs_iget5_test(struct inode *inode, void *opaque) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | { |
Dave Johnson | a97c9bf | 2005-09-06 15:17:40 -0700 | [diff] [blame] | 46 | struct cramfs_inode *cramfs_inode = opaque; |
| 47 | |
| 48 | if (inode->i_ino != CRAMINO(cramfs_inode)) |
| 49 | return 0; /* does not match */ |
| 50 | |
| 51 | if (inode->i_ino != 1) |
| 52 | return 1; |
| 53 | |
| 54 | /* all empty directories, char, block, pipe, and sock, share inode #1 */ |
| 55 | |
| 56 | if ((inode->i_mode != cramfs_inode->mode) || |
| 57 | (inode->i_gid != cramfs_inode->gid) || |
| 58 | (inode->i_uid != cramfs_inode->uid)) |
| 59 | return 0; /* does not match */ |
| 60 | |
| 61 | if ((S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) && |
| 62 | (inode->i_rdev != old_decode_dev(cramfs_inode->size))) |
| 63 | return 0; /* does not match */ |
| 64 | |
| 65 | return 1; /* matches */ |
| 66 | } |
| 67 | |
| 68 | static int cramfs_iget5_set(struct inode *inode, void *opaque) |
| 69 | { |
Dave Johnson | ff3aea0 | 2006-03-06 15:42:36 -0800 | [diff] [blame] | 70 | static struct timespec zerotime; |
Dave Johnson | a97c9bf | 2005-09-06 15:17:40 -0700 | [diff] [blame] | 71 | struct cramfs_inode *cramfs_inode = opaque; |
Dave Johnson | ff3aea0 | 2006-03-06 15:42:36 -0800 | [diff] [blame] | 72 | inode->i_mode = cramfs_inode->mode; |
| 73 | inode->i_uid = cramfs_inode->uid; |
| 74 | inode->i_size = cramfs_inode->size; |
| 75 | inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1; |
Dave Johnson | ff3aea0 | 2006-03-06 15:42:36 -0800 | [diff] [blame] | 76 | inode->i_gid = cramfs_inode->gid; |
| 77 | /* Struct copy intentional */ |
| 78 | inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime; |
Dave Johnson | a97c9bf | 2005-09-06 15:17:40 -0700 | [diff] [blame] | 79 | inode->i_ino = CRAMINO(cramfs_inode); |
Dave Johnson | ff3aea0 | 2006-03-06 15:42:36 -0800 | [diff] [blame] | 80 | /* inode->i_nlink is left 1 - arguably wrong for directories, |
| 81 | but it's the best we can do without reading the directory |
| 82 | contents. 1 yields the right result in GNU find, even |
| 83 | without -noleaf option. */ |
| 84 | if (S_ISREG(inode->i_mode)) { |
| 85 | inode->i_fop = &generic_ro_fops; |
| 86 | inode->i_data.a_ops = &cramfs_aops; |
| 87 | } else if (S_ISDIR(inode->i_mode)) { |
| 88 | inode->i_op = &cramfs_dir_inode_operations; |
| 89 | inode->i_fop = &cramfs_directory_operations; |
| 90 | } else if (S_ISLNK(inode->i_mode)) { |
| 91 | inode->i_op = &page_symlink_inode_operations; |
| 92 | inode->i_data.a_ops = &cramfs_aops; |
| 93 | } else { |
| 94 | inode->i_size = 0; |
| 95 | inode->i_blocks = 0; |
| 96 | init_special_inode(inode, inode->i_mode, |
| 97 | old_decode_dev(cramfs_inode->size)); |
| 98 | } |
Dave Johnson | a97c9bf | 2005-09-06 15:17:40 -0700 | [diff] [blame] | 99 | return 0; |
| 100 | } |
| 101 | |
| 102 | static struct inode *get_cramfs_inode(struct super_block *sb, |
| 103 | struct cramfs_inode * cramfs_inode) |
| 104 | { |
| 105 | struct inode *inode = iget5_locked(sb, CRAMINO(cramfs_inode), |
| 106 | cramfs_iget5_test, cramfs_iget5_set, |
| 107 | cramfs_inode); |
Dave Johnson | a97c9bf | 2005-09-06 15:17:40 -0700 | [diff] [blame] | 108 | if (inode && (inode->i_state & I_NEW)) { |
Dave Johnson | a97c9bf | 2005-09-06 15:17:40 -0700 | [diff] [blame] | 109 | unlock_new_inode(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | } |
| 111 | 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 | |
| 138 | static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE]; |
| 139 | static unsigned buffer_blocknr[READ_BUFFERS]; |
| 140 | static struct super_block * buffer_dev[READ_BUFFERS]; |
| 141 | static 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 | */ |
| 147 | static 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]; |
| 151 | unsigned i, blocknr, buffer, unread; |
| 152 | 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. */ |
| 178 | unread = 0; |
| 179 | for (i = 0; i < BLKS_PER_BUF; i++) { |
| 180 | struct page *page = NULL; |
| 181 | |
| 182 | if (blocknr + i < devsize) { |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 183 | page = read_mapping_page(mapping, blocknr + i, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | /* 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 | |
| 222 | static void cramfs_put_super(struct super_block *sb) |
| 223 | { |
| 224 | kfree(sb->s_fs_info); |
| 225 | sb->s_fs_info = NULL; |
| 226 | } |
| 227 | |
| 228 | static int cramfs_remount(struct super_block *sb, int *flags, char *data) |
| 229 | { |
| 230 | *flags |= MS_RDONLY; |
| 231 | return 0; |
| 232 | } |
| 233 | |
| 234 | static 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 Issaris | f8314dc | 2006-09-27 01:49:37 -0700 | [diff] [blame] | 244 | sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | if (!sbi) |
| 246 | return -ENOMEM; |
| 247 | sb->s_fs_info = sbi; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | |
| 249 | /* Invalidate the read buffers on mount: think disk change.. */ |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 250 | mutex_lock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | 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 Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 256 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | |
| 258 | /* Do sanity checks on the superblock */ |
| 259 | if (super.magic != CRAMFS_MAGIC) { |
| 260 | /* check at 512 byte offset */ |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 261 | mutex_lock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super)); |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 263 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | if (super.magic != CRAMFS_MAGIC) { |
| 265 | if (!silent) |
| 266 | printk(KERN_ERR "cramfs: wrong magic\n"); |
| 267 | goto out; |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | /* get feature flags first */ |
| 272 | if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) { |
| 273 | printk(KERN_ERR "cramfs: unsupported filesystem features\n"); |
| 274 | goto out; |
| 275 | } |
| 276 | |
| 277 | /* Check that the root inode is in a sane state */ |
| 278 | if (!S_ISDIR(super.root.mode)) { |
| 279 | printk(KERN_ERR "cramfs: root is not a directory\n"); |
| 280 | goto out; |
| 281 | } |
| 282 | root_offset = super.root.offset << 2; |
| 283 | if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) { |
| 284 | sbi->size=super.size; |
| 285 | sbi->blocks=super.fsid.blocks; |
| 286 | sbi->files=super.fsid.files; |
| 287 | } else { |
| 288 | sbi->size=1<<28; |
| 289 | sbi->blocks=0; |
| 290 | sbi->files=0; |
| 291 | } |
| 292 | sbi->magic=super.magic; |
| 293 | sbi->flags=super.flags; |
| 294 | if (root_offset == 0) |
| 295 | printk(KERN_INFO "cramfs: empty filesystem"); |
| 296 | else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) && |
| 297 | ((root_offset != sizeof(struct cramfs_super)) && |
| 298 | (root_offset != 512 + sizeof(struct cramfs_super)))) |
| 299 | { |
| 300 | printk(KERN_ERR "cramfs: bad root offset %lu\n", root_offset); |
| 301 | goto out; |
| 302 | } |
| 303 | |
| 304 | /* Set it all up.. */ |
| 305 | sb->s_op = &cramfs_ops; |
| 306 | root = get_cramfs_inode(sb, &super.root); |
| 307 | if (!root) |
| 308 | goto out; |
| 309 | sb->s_root = d_alloc_root(root); |
| 310 | if (!sb->s_root) { |
| 311 | iput(root); |
| 312 | goto out; |
| 313 | } |
| 314 | return 0; |
| 315 | out: |
| 316 | kfree(sbi); |
| 317 | sb->s_fs_info = NULL; |
| 318 | return -EINVAL; |
| 319 | } |
| 320 | |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 321 | static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | { |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 323 | struct super_block *sb = dentry->d_sb; |
| 324 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | buf->f_type = CRAMFS_MAGIC; |
| 326 | buf->f_bsize = PAGE_CACHE_SIZE; |
| 327 | buf->f_blocks = CRAMFS_SB(sb)->blocks; |
| 328 | buf->f_bfree = 0; |
| 329 | buf->f_bavail = 0; |
| 330 | buf->f_files = CRAMFS_SB(sb)->files; |
| 331 | buf->f_ffree = 0; |
| 332 | buf->f_namelen = CRAMFS_MAXPATHLEN; |
| 333 | return 0; |
| 334 | } |
| 335 | |
| 336 | /* |
| 337 | * Read a cramfs directory entry. |
| 338 | */ |
| 339 | static int cramfs_readdir(struct file *filp, void *dirent, filldir_t filldir) |
| 340 | { |
Josef Sipek | 352d8af | 2006-12-08 02:36:58 -0800 | [diff] [blame] | 341 | struct inode *inode = filp->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | struct super_block *sb = inode->i_sb; |
| 343 | char *buf; |
| 344 | unsigned int offset; |
| 345 | int copied; |
| 346 | |
| 347 | /* Offset within the thing. */ |
| 348 | offset = filp->f_pos; |
| 349 | if (offset >= inode->i_size) |
| 350 | return 0; |
| 351 | /* Directory entries are always 4-byte aligned */ |
| 352 | if (offset & 3) |
| 353 | return -EINVAL; |
| 354 | |
| 355 | buf = kmalloc(256, GFP_KERNEL); |
| 356 | if (!buf) |
| 357 | return -ENOMEM; |
| 358 | |
| 359 | copied = 0; |
| 360 | while (offset < inode->i_size) { |
| 361 | struct cramfs_inode *de; |
| 362 | unsigned long nextoffset; |
| 363 | char *name; |
| 364 | ino_t ino; |
| 365 | mode_t mode; |
| 366 | int namelen, error; |
| 367 | |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 368 | mutex_lock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+256); |
| 370 | name = (char *)(de+1); |
| 371 | |
| 372 | /* |
| 373 | * Namelengths on disk are shifted by two |
| 374 | * and the name padded out to 4-byte boundaries |
| 375 | * with zeroes. |
| 376 | */ |
| 377 | namelen = de->namelen << 2; |
| 378 | memcpy(buf, name, namelen); |
| 379 | ino = CRAMINO(de); |
| 380 | mode = de->mode; |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 381 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | nextoffset = offset + sizeof(*de) + namelen; |
| 383 | for (;;) { |
| 384 | if (!namelen) { |
| 385 | kfree(buf); |
| 386 | return -EIO; |
| 387 | } |
| 388 | if (buf[namelen-1]) |
| 389 | break; |
| 390 | namelen--; |
| 391 | } |
| 392 | error = filldir(dirent, buf, namelen, offset, ino, mode >> 12); |
| 393 | if (error) |
| 394 | break; |
| 395 | |
| 396 | offset = nextoffset; |
| 397 | filp->f_pos = offset; |
| 398 | copied++; |
| 399 | } |
| 400 | kfree(buf); |
| 401 | return 0; |
| 402 | } |
| 403 | |
| 404 | /* |
| 405 | * Lookup and fill in the inode data.. |
| 406 | */ |
| 407 | static struct dentry * cramfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) |
| 408 | { |
| 409 | unsigned int offset = 0; |
| 410 | int sorted; |
| 411 | |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 412 | mutex_lock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS; |
| 414 | while (offset < dir->i_size) { |
| 415 | struct cramfs_inode *de; |
| 416 | char *name; |
| 417 | int namelen, retval; |
| 418 | |
| 419 | de = cramfs_read(dir->i_sb, OFFSET(dir) + offset, sizeof(*de)+256); |
| 420 | name = (char *)(de+1); |
| 421 | |
| 422 | /* Try to take advantage of sorted directories */ |
| 423 | if (sorted && (dentry->d_name.name[0] < name[0])) |
| 424 | break; |
| 425 | |
| 426 | namelen = de->namelen << 2; |
| 427 | offset += sizeof(*de) + namelen; |
| 428 | |
| 429 | /* Quick check that the name is roughly the right length */ |
| 430 | if (((dentry->d_name.len + 3) & ~3) != namelen) |
| 431 | continue; |
| 432 | |
| 433 | for (;;) { |
| 434 | if (!namelen) { |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 435 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | return ERR_PTR(-EIO); |
| 437 | } |
| 438 | if (name[namelen-1]) |
| 439 | break; |
| 440 | namelen--; |
| 441 | } |
| 442 | if (namelen != dentry->d_name.len) |
| 443 | continue; |
| 444 | retval = memcmp(dentry->d_name.name, name, namelen); |
| 445 | if (retval > 0) |
| 446 | continue; |
| 447 | if (!retval) { |
| 448 | struct cramfs_inode entry = *de; |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 449 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | d_add(dentry, get_cramfs_inode(dir->i_sb, &entry)); |
| 451 | return NULL; |
| 452 | } |
| 453 | /* else (retval < 0) */ |
| 454 | if (sorted) |
| 455 | break; |
| 456 | } |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 457 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 458 | d_add(dentry, NULL); |
| 459 | return NULL; |
| 460 | } |
| 461 | |
| 462 | static int cramfs_readpage(struct file *file, struct page * page) |
| 463 | { |
| 464 | struct inode *inode = page->mapping->host; |
| 465 | u32 maxblock, bytes_filled; |
| 466 | void *pgdata; |
| 467 | |
| 468 | maxblock = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 469 | bytes_filled = 0; |
| 470 | if (page->index < maxblock) { |
| 471 | struct super_block *sb = inode->i_sb; |
| 472 | u32 blkptr_offset = OFFSET(inode) + page->index*4; |
| 473 | u32 start_offset, compr_len; |
| 474 | |
| 475 | start_offset = OFFSET(inode) + maxblock*4; |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 476 | mutex_lock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | if (page->index) |
| 478 | start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4, 4); |
| 479 | compr_len = (*(u32 *) cramfs_read(sb, blkptr_offset, 4) - start_offset); |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 480 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 481 | pgdata = kmap(page); |
| 482 | if (compr_len == 0) |
| 483 | ; /* hole */ |
Phillip Lougher | 8bb0269 | 2006-12-06 20:37:20 -0800 | [diff] [blame] | 484 | else if (compr_len > (PAGE_CACHE_SIZE << 1)) |
| 485 | printk(KERN_ERR "cramfs: bad compressed blocksize %u\n", compr_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | else { |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 487 | mutex_lock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | bytes_filled = cramfs_uncompress_block(pgdata, |
| 489 | PAGE_CACHE_SIZE, |
| 490 | cramfs_read(sb, start_offset, compr_len), |
| 491 | compr_len); |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 492 | mutex_unlock(&read_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 493 | } |
| 494 | } else |
| 495 | pgdata = kmap(page); |
| 496 | memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled); |
| 497 | kunmap(page); |
| 498 | flush_dcache_page(page); |
| 499 | SetPageUptodate(page); |
| 500 | unlock_page(page); |
| 501 | return 0; |
| 502 | } |
| 503 | |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 504 | static const struct address_space_operations cramfs_aops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | .readpage = cramfs_readpage |
| 506 | }; |
| 507 | |
| 508 | /* |
| 509 | * Our operations: |
| 510 | */ |
| 511 | |
| 512 | /* |
| 513 | * A directory can only readdir |
| 514 | */ |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 515 | static const struct file_operations cramfs_directory_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | .llseek = generic_file_llseek, |
| 517 | .read = generic_read_dir, |
| 518 | .readdir = cramfs_readdir, |
| 519 | }; |
| 520 | |
Arjan van de Ven | 754661f | 2007-02-12 00:55:38 -0800 | [diff] [blame] | 521 | static const struct inode_operations cramfs_dir_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | .lookup = cramfs_lookup, |
| 523 | }; |
| 524 | |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 525 | static const struct super_operations cramfs_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | .put_super = cramfs_put_super, |
| 527 | .remount_fs = cramfs_remount, |
| 528 | .statfs = cramfs_statfs, |
| 529 | }; |
| 530 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 531 | static int cramfs_get_sb(struct file_system_type *fs_type, |
| 532 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 533 | { |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 534 | return get_sb_bdev(fs_type, flags, dev_name, data, cramfs_fill_super, |
| 535 | mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | } |
| 537 | |
| 538 | static struct file_system_type cramfs_fs_type = { |
| 539 | .owner = THIS_MODULE, |
| 540 | .name = "cramfs", |
| 541 | .get_sb = cramfs_get_sb, |
| 542 | .kill_sb = kill_block_super, |
| 543 | .fs_flags = FS_REQUIRES_DEV, |
| 544 | }; |
| 545 | |
| 546 | static int __init init_cramfs_fs(void) |
| 547 | { |
Alexey Dobriyan | 50d44ed | 2006-09-29 02:01:04 -0700 | [diff] [blame] | 548 | int rv; |
| 549 | |
| 550 | rv = cramfs_uncompress_init(); |
| 551 | if (rv < 0) |
| 552 | return rv; |
| 553 | rv = register_filesystem(&cramfs_fs_type); |
| 554 | if (rv < 0) |
| 555 | cramfs_uncompress_exit(); |
| 556 | return rv; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 557 | } |
| 558 | |
| 559 | static void __exit exit_cramfs_fs(void) |
| 560 | { |
| 561 | cramfs_uncompress_exit(); |
| 562 | unregister_filesystem(&cramfs_fs_type); |
| 563 | } |
| 564 | |
| 565 | module_init(init_cramfs_fs) |
| 566 | module_exit(exit_cramfs_fs) |
| 567 | MODULE_LICENSE("GPL"); |