11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * Compressed rom filesystem for Linux. 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 1999 Linus Torvalds. 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * This file is released under the GPL. 71da177e4SLinus Torvalds */ 81da177e4SLinus Torvalds 91da177e4SLinus Torvalds /* 101da177e4SLinus Torvalds * These are the VFS interfaces to the compressed rom filesystem. 111da177e4SLinus Torvalds * The actual compression is based on zlib, see the other files. 121da177e4SLinus Torvalds */ 131da177e4SLinus Torvalds 141da177e4SLinus Torvalds #include <linux/module.h> 151da177e4SLinus Torvalds #include <linux/fs.h> 161da177e4SLinus Torvalds #include <linux/pagemap.h> 171da177e4SLinus Torvalds #include <linux/init.h> 181da177e4SLinus Torvalds #include <linux/string.h> 191da177e4SLinus Torvalds #include <linux/blkdev.h> 201da177e4SLinus Torvalds #include <linux/slab.h> 211da177e4SLinus Torvalds #include <linux/vfs.h> 22353ab6e9SIngo Molnar #include <linux/mutex.h> 23f7f4f4ddSAl Viro #include <uapi/linux/cramfs_fs.h> 241da177e4SLinus Torvalds #include <asm/uaccess.h> 251da177e4SLinus Torvalds 26f7f4f4ddSAl Viro #include "internal.h" 27f7f4f4ddSAl Viro 28f7f4f4ddSAl Viro /* 29f7f4f4ddSAl Viro * cramfs super-block data in memory 30f7f4f4ddSAl Viro */ 31f7f4f4ddSAl Viro struct cramfs_sb_info { 32f7f4f4ddSAl Viro unsigned long magic; 33f7f4f4ddSAl Viro unsigned long size; 34f7f4f4ddSAl Viro unsigned long blocks; 35f7f4f4ddSAl Viro unsigned long files; 36f7f4f4ddSAl Viro unsigned long flags; 37f7f4f4ddSAl Viro }; 38f7f4f4ddSAl Viro 39f7f4f4ddSAl Viro static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb) 40f7f4f4ddSAl Viro { 41f7f4f4ddSAl Viro return sb->s_fs_info; 42f7f4f4ddSAl Viro } 43f7f4f4ddSAl Viro 44ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations cramfs_ops; 45754661f1SArjan van de Ven static const struct inode_operations cramfs_dir_inode_operations; 464b6f5d20SArjan van de Ven static const struct file_operations cramfs_directory_operations; 47f5e54d6eSChristoph Hellwig static const struct address_space_operations cramfs_aops; 481da177e4SLinus Torvalds 49353ab6e9SIngo Molnar static DEFINE_MUTEX(read_mutex); 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds 526f772fe6SStefani Seibold /* These macros may change in future, to provide better st_ino semantics. */ 531da177e4SLinus Torvalds #define OFFSET(x) ((x)->i_ino) 541da177e4SLinus Torvalds 550577d1baSAl Viro static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset) 561da177e4SLinus Torvalds { 576f772fe6SStefani Seibold if (!cino->offset) 586f772fe6SStefani Seibold return offset + 1; 596f772fe6SStefani Seibold if (!cino->size) 606f772fe6SStefani Seibold return offset + 1; 616f772fe6SStefani Seibold 626f772fe6SStefani Seibold /* 636f772fe6SStefani Seibold * The file mode test fixes buggy mkcramfs implementations where 646f772fe6SStefani Seibold * cramfs_inode->offset is set to a non zero value for entries 656f772fe6SStefani Seibold * which did not contain data, like devices node and fifos. 666f772fe6SStefani Seibold */ 676f772fe6SStefani Seibold switch (cino->mode & S_IFMT) { 686f772fe6SStefani Seibold case S_IFREG: 696f772fe6SStefani Seibold case S_IFDIR: 706f772fe6SStefani Seibold case S_IFLNK: 716f772fe6SStefani Seibold return cino->offset << 2; 726f772fe6SStefani Seibold default: 736f772fe6SStefani Seibold break; 746f772fe6SStefani Seibold } 756f772fe6SStefani Seibold return offset + 1; 766f772fe6SStefani Seibold } 776f772fe6SStefani Seibold 786f772fe6SStefani Seibold static struct inode *get_cramfs_inode(struct super_block *sb, 790577d1baSAl Viro const struct cramfs_inode *cramfs_inode, unsigned int offset) 806f772fe6SStefani Seibold { 816f772fe6SStefani Seibold struct inode *inode; 8282d63fc9SAl Viro static struct timespec zerotime; 836f772fe6SStefani Seibold 846f772fe6SStefani Seibold inode = iget_locked(sb, cramino(cramfs_inode, offset)); 856f772fe6SStefani Seibold if (!inode) 866f772fe6SStefani Seibold return ERR_PTR(-ENOMEM); 876f772fe6SStefani Seibold if (!(inode->i_state & I_NEW)) 886f772fe6SStefani Seibold return inode; 896f772fe6SStefani Seibold 906f772fe6SStefani Seibold switch (cramfs_inode->mode & S_IFMT) { 916f772fe6SStefani Seibold case S_IFREG: 926f772fe6SStefani Seibold inode->i_fop = &generic_ro_fops; 936f772fe6SStefani Seibold inode->i_data.a_ops = &cramfs_aops; 946f772fe6SStefani Seibold break; 956f772fe6SStefani Seibold case S_IFDIR: 966f772fe6SStefani Seibold inode->i_op = &cramfs_dir_inode_operations; 976f772fe6SStefani Seibold inode->i_fop = &cramfs_directory_operations; 986f772fe6SStefani Seibold break; 996f772fe6SStefani Seibold case S_IFLNK: 1006f772fe6SStefani Seibold inode->i_op = &page_symlink_inode_operations; 1016f772fe6SStefani Seibold inode->i_data.a_ops = &cramfs_aops; 1026f772fe6SStefani Seibold break; 1036f772fe6SStefani Seibold default: 1046f772fe6SStefani Seibold init_special_inode(inode, cramfs_inode->mode, 1056f772fe6SStefani Seibold old_decode_dev(cramfs_inode->size)); 1066f772fe6SStefani Seibold } 1076f772fe6SStefani Seibold 1081da177e4SLinus Torvalds inode->i_mode = cramfs_inode->mode; 109a7d9cfe9SEric W. Biederman i_uid_write(inode, cramfs_inode->uid); 110a7d9cfe9SEric W. Biederman i_gid_write(inode, cramfs_inode->gid); 1116f772fe6SStefani Seibold 1126f772fe6SStefani Seibold /* if the lower 2 bits are zero, the inode contains data */ 1136f772fe6SStefani Seibold if (!(inode->i_ino & 3)) { 1141da177e4SLinus Torvalds inode->i_size = cramfs_inode->size; 1151da177e4SLinus Torvalds inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1; 1166f772fe6SStefani Seibold } 1176f772fe6SStefani Seibold 1181da177e4SLinus Torvalds /* Struct copy intentional */ 1191da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime; 1201da177e4SLinus Torvalds /* inode->i_nlink is left 1 - arguably wrong for directories, 1211da177e4SLinus Torvalds but it's the best we can do without reading the directory 1221da177e4SLinus Torvalds contents. 1 yields the right result in GNU find, even 1231da177e4SLinus Torvalds without -noleaf option. */ 1241da177e4SLinus Torvalds 12577b8a75fSAl Viro unlock_new_inode(inode); 1266f772fe6SStefani Seibold 12777b8a75fSAl Viro return inode; 12882d63fc9SAl Viro } 12982d63fc9SAl Viro 1301da177e4SLinus Torvalds /* 1311da177e4SLinus Torvalds * We have our own block cache: don't fill up the buffer cache 1321da177e4SLinus Torvalds * with the rom-image, because the way the filesystem is set 1331da177e4SLinus Torvalds * up the accesses should be fairly regular and cached in the 1341da177e4SLinus Torvalds * page cache and dentry tree anyway.. 1351da177e4SLinus Torvalds * 1361da177e4SLinus Torvalds * This also acts as a way to guarantee contiguous areas of up to 1371da177e4SLinus Torvalds * BLKS_PER_BUF*PAGE_CACHE_SIZE, so that the caller doesn't need to 1381da177e4SLinus Torvalds * worry about end-of-buffer issues even when decompressing a full 1391da177e4SLinus Torvalds * page cache. 1401da177e4SLinus Torvalds */ 1411da177e4SLinus Torvalds #define READ_BUFFERS (2) 1421da177e4SLinus Torvalds /* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */ 1431da177e4SLinus Torvalds #define NEXT_BUFFER(_ix) ((_ix) ^ 1) 1441da177e4SLinus Torvalds 1451da177e4SLinus Torvalds /* 1461da177e4SLinus Torvalds * BLKS_PER_BUF_SHIFT should be at least 2 to allow for "compressed" 1471da177e4SLinus Torvalds * data that takes up more space than the original and with unlucky 1481da177e4SLinus Torvalds * alignment. 1491da177e4SLinus Torvalds */ 1501da177e4SLinus Torvalds #define BLKS_PER_BUF_SHIFT (2) 1511da177e4SLinus Torvalds #define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT) 1521da177e4SLinus Torvalds #define BUFFER_SIZE (BLKS_PER_BUF*PAGE_CACHE_SIZE) 1531da177e4SLinus Torvalds 1541da177e4SLinus Torvalds static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE]; 1551da177e4SLinus Torvalds static unsigned buffer_blocknr[READ_BUFFERS]; 1561da177e4SLinus Torvalds static struct super_block * buffer_dev[READ_BUFFERS]; 1571da177e4SLinus Torvalds static int next_buffer; 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds /* 1601da177e4SLinus Torvalds * Returns a pointer to a buffer containing at least LEN bytes of 1611da177e4SLinus Torvalds * filesystem starting at byte offset OFFSET into the filesystem. 1621da177e4SLinus Torvalds */ 1631da177e4SLinus Torvalds static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned int len) 1641da177e4SLinus Torvalds { 1651da177e4SLinus Torvalds struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1661da177e4SLinus Torvalds struct page *pages[BLKS_PER_BUF]; 1676bbfb077SAndi Drebes unsigned i, blocknr, buffer; 1681da177e4SLinus Torvalds unsigned long devsize; 1691da177e4SLinus Torvalds char *data; 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds if (!len) 1721da177e4SLinus Torvalds return NULL; 1731da177e4SLinus Torvalds blocknr = offset >> PAGE_CACHE_SHIFT; 1741da177e4SLinus Torvalds offset &= PAGE_CACHE_SIZE - 1; 1751da177e4SLinus Torvalds 1761da177e4SLinus Torvalds /* Check if an existing buffer already has the data.. */ 1771da177e4SLinus Torvalds for (i = 0; i < READ_BUFFERS; i++) { 1781da177e4SLinus Torvalds unsigned int blk_offset; 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds if (buffer_dev[i] != sb) 1811da177e4SLinus Torvalds continue; 1821da177e4SLinus Torvalds if (blocknr < buffer_blocknr[i]) 1831da177e4SLinus Torvalds continue; 1841da177e4SLinus Torvalds blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_SHIFT; 1851da177e4SLinus Torvalds blk_offset += offset; 1861da177e4SLinus Torvalds if (blk_offset + len > BUFFER_SIZE) 1871da177e4SLinus Torvalds continue; 1881da177e4SLinus Torvalds return read_buffers[i] + blk_offset; 1891da177e4SLinus Torvalds } 1901da177e4SLinus Torvalds 1911da177e4SLinus Torvalds devsize = mapping->host->i_size >> PAGE_CACHE_SHIFT; 1921da177e4SLinus Torvalds 1931da177e4SLinus Torvalds /* Ok, read in BLKS_PER_BUF pages completely first. */ 1941da177e4SLinus Torvalds for (i = 0; i < BLKS_PER_BUF; i++) { 1951da177e4SLinus Torvalds struct page *page = NULL; 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds if (blocknr + i < devsize) { 19867f9fd91SSasha Levin page = read_mapping_page(mapping, blocknr + i, NULL); 1991da177e4SLinus Torvalds /* synchronous error? */ 2001da177e4SLinus Torvalds if (IS_ERR(page)) 2011da177e4SLinus Torvalds page = NULL; 2021da177e4SLinus Torvalds } 2031da177e4SLinus Torvalds pages[i] = page; 2041da177e4SLinus Torvalds } 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds for (i = 0; i < BLKS_PER_BUF; i++) { 2071da177e4SLinus Torvalds struct page *page = pages[i]; 2081da177e4SLinus Torvalds if (page) { 2091da177e4SLinus Torvalds wait_on_page_locked(page); 2101da177e4SLinus Torvalds if (!PageUptodate(page)) { 2111da177e4SLinus Torvalds /* asynchronous error */ 2121da177e4SLinus Torvalds page_cache_release(page); 2131da177e4SLinus Torvalds pages[i] = NULL; 2141da177e4SLinus Torvalds } 2151da177e4SLinus Torvalds } 2161da177e4SLinus Torvalds } 2171da177e4SLinus Torvalds 2181da177e4SLinus Torvalds buffer = next_buffer; 2191da177e4SLinus Torvalds next_buffer = NEXT_BUFFER(buffer); 2201da177e4SLinus Torvalds buffer_blocknr[buffer] = blocknr; 2211da177e4SLinus Torvalds buffer_dev[buffer] = sb; 2221da177e4SLinus Torvalds 2231da177e4SLinus Torvalds data = read_buffers[buffer]; 2241da177e4SLinus Torvalds for (i = 0; i < BLKS_PER_BUF; i++) { 2251da177e4SLinus Torvalds struct page *page = pages[i]; 2261da177e4SLinus Torvalds if (page) { 2271da177e4SLinus Torvalds memcpy(data, kmap(page), PAGE_CACHE_SIZE); 2281da177e4SLinus Torvalds kunmap(page); 2291da177e4SLinus Torvalds page_cache_release(page); 2301da177e4SLinus Torvalds } else 2311da177e4SLinus Torvalds memset(data, 0, PAGE_CACHE_SIZE); 2321da177e4SLinus Torvalds data += PAGE_CACHE_SIZE; 2331da177e4SLinus Torvalds } 2341da177e4SLinus Torvalds return read_buffers[buffer] + offset; 2351da177e4SLinus Torvalds } 2361da177e4SLinus Torvalds 2372309fb8eSAl Viro static void cramfs_kill_sb(struct super_block *sb) 2381da177e4SLinus Torvalds { 239f7f4f4ddSAl Viro struct cramfs_sb_info *sbi = CRAMFS_SB(sb); 2402309fb8eSAl Viro kill_block_super(sb); 2412309fb8eSAl Viro kfree(sbi); 2421da177e4SLinus Torvalds } 2431da177e4SLinus Torvalds 2441da177e4SLinus Torvalds static int cramfs_remount(struct super_block *sb, int *flags, char *data) 2451da177e4SLinus Torvalds { 2461da177e4SLinus Torvalds *flags |= MS_RDONLY; 2471da177e4SLinus Torvalds return 0; 2481da177e4SLinus Torvalds } 2491da177e4SLinus Torvalds 2501da177e4SLinus Torvalds static int cramfs_fill_super(struct super_block *sb, void *data, int silent) 2511da177e4SLinus Torvalds { 2521da177e4SLinus Torvalds int i; 2531da177e4SLinus Torvalds struct cramfs_super super; 2541da177e4SLinus Torvalds unsigned long root_offset; 2551da177e4SLinus Torvalds struct cramfs_sb_info *sbi; 2561da177e4SLinus Torvalds struct inode *root; 2571da177e4SLinus Torvalds 2581da177e4SLinus Torvalds sb->s_flags |= MS_RDONLY; 2591da177e4SLinus Torvalds 260f8314dc6SPanagiotis Issaris sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL); 2611da177e4SLinus Torvalds if (!sbi) 2621da177e4SLinus Torvalds return -ENOMEM; 2631da177e4SLinus Torvalds sb->s_fs_info = sbi; 2641da177e4SLinus Torvalds 2651da177e4SLinus Torvalds /* Invalidate the read buffers on mount: think disk change.. */ 266353ab6e9SIngo Molnar mutex_lock(&read_mutex); 2671da177e4SLinus Torvalds for (i = 0; i < READ_BUFFERS; i++) 2681da177e4SLinus Torvalds buffer_blocknr[i] = -1; 2691da177e4SLinus Torvalds 2701da177e4SLinus Torvalds /* Read the first block and get the superblock from it */ 2711da177e4SLinus Torvalds memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super)); 272353ab6e9SIngo Molnar mutex_unlock(&read_mutex); 2731da177e4SLinus Torvalds 2741da177e4SLinus Torvalds /* Do sanity checks on the superblock */ 2751da177e4SLinus Torvalds if (super.magic != CRAMFS_MAGIC) { 2760cc785ecSMasanari Iida /* check for wrong endianness */ 277ac8d35c5SAndi Drebes if (super.magic == CRAMFS_MAGIC_WEND) { 278ac8d35c5SAndi Drebes if (!silent) 2790cc785ecSMasanari Iida printk(KERN_ERR "cramfs: wrong endianness\n"); 2802309fb8eSAl Viro return -EINVAL; 281ac8d35c5SAndi Drebes } 282ac8d35c5SAndi Drebes 2831da177e4SLinus Torvalds /* check at 512 byte offset */ 284353ab6e9SIngo Molnar mutex_lock(&read_mutex); 2851da177e4SLinus Torvalds memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super)); 286353ab6e9SIngo Molnar mutex_unlock(&read_mutex); 2871da177e4SLinus Torvalds if (super.magic != CRAMFS_MAGIC) { 288ac8d35c5SAndi Drebes if (super.magic == CRAMFS_MAGIC_WEND && !silent) 2890cc785ecSMasanari Iida printk(KERN_ERR "cramfs: wrong endianness\n"); 290ac8d35c5SAndi Drebes else if (!silent) 2911da177e4SLinus Torvalds printk(KERN_ERR "cramfs: wrong magic\n"); 2922309fb8eSAl Viro return -EINVAL; 2931da177e4SLinus Torvalds } 2941da177e4SLinus Torvalds } 2951da177e4SLinus Torvalds 2961da177e4SLinus Torvalds /* get feature flags first */ 2971da177e4SLinus Torvalds if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) { 2981da177e4SLinus Torvalds printk(KERN_ERR "cramfs: unsupported filesystem features\n"); 2992309fb8eSAl Viro return -EINVAL; 3001da177e4SLinus Torvalds } 3011da177e4SLinus Torvalds 3021da177e4SLinus Torvalds /* Check that the root inode is in a sane state */ 3031da177e4SLinus Torvalds if (!S_ISDIR(super.root.mode)) { 3041da177e4SLinus Torvalds printk(KERN_ERR "cramfs: root is not a directory\n"); 3052309fb8eSAl Viro return -EINVAL; 3061da177e4SLinus Torvalds } 3076f772fe6SStefani Seibold /* correct strange, hard-coded permissions of mkcramfs */ 3086f772fe6SStefani Seibold super.root.mode |= (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH); 3096f772fe6SStefani Seibold 3101da177e4SLinus Torvalds root_offset = super.root.offset << 2; 3111da177e4SLinus Torvalds if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) { 3121da177e4SLinus Torvalds sbi->size=super.size; 3131da177e4SLinus Torvalds sbi->blocks=super.fsid.blocks; 3141da177e4SLinus Torvalds sbi->files=super.fsid.files; 3151da177e4SLinus Torvalds } else { 3161da177e4SLinus Torvalds sbi->size=1<<28; 3171da177e4SLinus Torvalds sbi->blocks=0; 3181da177e4SLinus Torvalds sbi->files=0; 3191da177e4SLinus Torvalds } 3201da177e4SLinus Torvalds sbi->magic=super.magic; 3211da177e4SLinus Torvalds sbi->flags=super.flags; 3221da177e4SLinus Torvalds if (root_offset == 0) 3231da177e4SLinus Torvalds printk(KERN_INFO "cramfs: empty filesystem"); 3241da177e4SLinus Torvalds else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) && 3251da177e4SLinus Torvalds ((root_offset != sizeof(struct cramfs_super)) && 3261da177e4SLinus Torvalds (root_offset != 512 + sizeof(struct cramfs_super)))) 3271da177e4SLinus Torvalds { 3281da177e4SLinus Torvalds printk(KERN_ERR "cramfs: bad root offset %lu\n", root_offset); 3292309fb8eSAl Viro return -EINVAL; 3301da177e4SLinus Torvalds } 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvalds /* Set it all up.. */ 3331da177e4SLinus Torvalds sb->s_op = &cramfs_ops; 3346f772fe6SStefani Seibold root = get_cramfs_inode(sb, &super.root, 0); 3350577d1baSAl Viro if (IS_ERR(root)) 3362309fb8eSAl Viro return PTR_ERR(root); 33748fde701SAl Viro sb->s_root = d_make_root(root); 33848fde701SAl Viro if (!sb->s_root) 3392309fb8eSAl Viro return -ENOMEM; 3401da177e4SLinus Torvalds return 0; 3411da177e4SLinus Torvalds } 3421da177e4SLinus Torvalds 343726c3342SDavid Howells static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf) 3441da177e4SLinus Torvalds { 345726c3342SDavid Howells struct super_block *sb = dentry->d_sb; 34694ea77acSColy Li u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 347726c3342SDavid Howells 3481da177e4SLinus Torvalds buf->f_type = CRAMFS_MAGIC; 3491da177e4SLinus Torvalds buf->f_bsize = PAGE_CACHE_SIZE; 3501da177e4SLinus Torvalds buf->f_blocks = CRAMFS_SB(sb)->blocks; 3511da177e4SLinus Torvalds buf->f_bfree = 0; 3521da177e4SLinus Torvalds buf->f_bavail = 0; 3531da177e4SLinus Torvalds buf->f_files = CRAMFS_SB(sb)->files; 3541da177e4SLinus Torvalds buf->f_ffree = 0; 35594ea77acSColy Li buf->f_fsid.val[0] = (u32)id; 35694ea77acSColy Li buf->f_fsid.val[1] = (u32)(id >> 32); 3571da177e4SLinus Torvalds buf->f_namelen = CRAMFS_MAXPATHLEN; 3581da177e4SLinus Torvalds return 0; 3591da177e4SLinus Torvalds } 3601da177e4SLinus Torvalds 3611da177e4SLinus Torvalds /* 3621da177e4SLinus Torvalds * Read a cramfs directory entry. 3631da177e4SLinus Torvalds */ 3646f7f231eSAl Viro static int cramfs_readdir(struct file *file, struct dir_context *ctx) 3651da177e4SLinus Torvalds { 3666f7f231eSAl Viro struct inode *inode = file_inode(file); 3671da177e4SLinus Torvalds struct super_block *sb = inode->i_sb; 3681da177e4SLinus Torvalds char *buf; 3691da177e4SLinus Torvalds unsigned int offset; 3701da177e4SLinus Torvalds 3711da177e4SLinus Torvalds /* Offset within the thing. */ 3726f7f231eSAl Viro if (ctx->pos >= inode->i_size) 3731da177e4SLinus Torvalds return 0; 3746f7f231eSAl Viro offset = ctx->pos; 3751da177e4SLinus Torvalds /* Directory entries are always 4-byte aligned */ 3761da177e4SLinus Torvalds if (offset & 3) 3771da177e4SLinus Torvalds return -EINVAL; 3781da177e4SLinus Torvalds 3794176ed59SAndi Drebes buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL); 3801da177e4SLinus Torvalds if (!buf) 3811da177e4SLinus Torvalds return -ENOMEM; 3821da177e4SLinus Torvalds 3831da177e4SLinus Torvalds while (offset < inode->i_size) { 3841da177e4SLinus Torvalds struct cramfs_inode *de; 3851da177e4SLinus Torvalds unsigned long nextoffset; 3861da177e4SLinus Torvalds char *name; 3871da177e4SLinus Torvalds ino_t ino; 388175a4eb7SAl Viro umode_t mode; 3896f7f231eSAl Viro int namelen; 3901da177e4SLinus Torvalds 391353ab6e9SIngo Molnar mutex_lock(&read_mutex); 3924176ed59SAndi Drebes de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN); 3931da177e4SLinus Torvalds name = (char *)(de+1); 3941da177e4SLinus Torvalds 3951da177e4SLinus Torvalds /* 3961da177e4SLinus Torvalds * Namelengths on disk are shifted by two 3971da177e4SLinus Torvalds * and the name padded out to 4-byte boundaries 3981da177e4SLinus Torvalds * with zeroes. 3991da177e4SLinus Torvalds */ 4001da177e4SLinus Torvalds namelen = de->namelen << 2; 4011da177e4SLinus Torvalds memcpy(buf, name, namelen); 4026f772fe6SStefani Seibold ino = cramino(de, OFFSET(inode) + offset); 4031da177e4SLinus Torvalds mode = de->mode; 404353ab6e9SIngo Molnar mutex_unlock(&read_mutex); 4051da177e4SLinus Torvalds nextoffset = offset + sizeof(*de) + namelen; 4061da177e4SLinus Torvalds for (;;) { 4071da177e4SLinus Torvalds if (!namelen) { 4081da177e4SLinus Torvalds kfree(buf); 4091da177e4SLinus Torvalds return -EIO; 4101da177e4SLinus Torvalds } 4111da177e4SLinus Torvalds if (buf[namelen-1]) 4121da177e4SLinus Torvalds break; 4131da177e4SLinus Torvalds namelen--; 4141da177e4SLinus Torvalds } 4156f7f231eSAl Viro if (!dir_emit(ctx, buf, namelen, ino, mode >> 12)) 4161da177e4SLinus Torvalds break; 4171da177e4SLinus Torvalds 4186f7f231eSAl Viro ctx->pos = offset = nextoffset; 4191da177e4SLinus Torvalds } 4201da177e4SLinus Torvalds kfree(buf); 4211da177e4SLinus Torvalds return 0; 4221da177e4SLinus Torvalds } 4231da177e4SLinus Torvalds 4241da177e4SLinus Torvalds /* 4251da177e4SLinus Torvalds * Lookup and fill in the inode data.. 4261da177e4SLinus Torvalds */ 42700cd8dd3SAl Viro static struct dentry * cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) 4281da177e4SLinus Torvalds { 4291da177e4SLinus Torvalds unsigned int offset = 0; 4300577d1baSAl Viro struct inode *inode = NULL; 4311da177e4SLinus Torvalds int sorted; 4321da177e4SLinus Torvalds 433353ab6e9SIngo Molnar mutex_lock(&read_mutex); 4341da177e4SLinus Torvalds sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS; 4351da177e4SLinus Torvalds while (offset < dir->i_size) { 4361da177e4SLinus Torvalds struct cramfs_inode *de; 4371da177e4SLinus Torvalds char *name; 4381da177e4SLinus Torvalds int namelen, retval; 4396f772fe6SStefani Seibold int dir_off = OFFSET(dir) + offset; 4401da177e4SLinus Torvalds 4416f772fe6SStefani Seibold de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN); 4421da177e4SLinus Torvalds name = (char *)(de+1); 4431da177e4SLinus Torvalds 4441da177e4SLinus Torvalds /* Try to take advantage of sorted directories */ 4451da177e4SLinus Torvalds if (sorted && (dentry->d_name.name[0] < name[0])) 4461da177e4SLinus Torvalds break; 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds namelen = de->namelen << 2; 4491da177e4SLinus Torvalds offset += sizeof(*de) + namelen; 4501da177e4SLinus Torvalds 4511da177e4SLinus Torvalds /* Quick check that the name is roughly the right length */ 4521da177e4SLinus Torvalds if (((dentry->d_name.len + 3) & ~3) != namelen) 4531da177e4SLinus Torvalds continue; 4541da177e4SLinus Torvalds 4551da177e4SLinus Torvalds for (;;) { 4561da177e4SLinus Torvalds if (!namelen) { 4570577d1baSAl Viro inode = ERR_PTR(-EIO); 4580577d1baSAl Viro goto out; 4591da177e4SLinus Torvalds } 4601da177e4SLinus Torvalds if (name[namelen-1]) 4611da177e4SLinus Torvalds break; 4621da177e4SLinus Torvalds namelen--; 4631da177e4SLinus Torvalds } 4641da177e4SLinus Torvalds if (namelen != dentry->d_name.len) 4651da177e4SLinus Torvalds continue; 4661da177e4SLinus Torvalds retval = memcmp(dentry->d_name.name, name, namelen); 4671da177e4SLinus Torvalds if (retval > 0) 4681da177e4SLinus Torvalds continue; 4691da177e4SLinus Torvalds if (!retval) { 4700577d1baSAl Viro inode = get_cramfs_inode(dir->i_sb, de, dir_off); 4710577d1baSAl Viro break; 4721da177e4SLinus Torvalds } 4731da177e4SLinus Torvalds /* else (retval < 0) */ 4741da177e4SLinus Torvalds if (sorted) 4751da177e4SLinus Torvalds break; 4761da177e4SLinus Torvalds } 4770577d1baSAl Viro out: 478353ab6e9SIngo Molnar mutex_unlock(&read_mutex); 4790577d1baSAl Viro if (IS_ERR(inode)) 4800577d1baSAl Viro return ERR_CAST(inode); 4810577d1baSAl Viro d_add(dentry, inode); 4821da177e4SLinus Torvalds return NULL; 4831da177e4SLinus Torvalds } 4841da177e4SLinus Torvalds 4851da177e4SLinus Torvalds static int cramfs_readpage(struct file *file, struct page * page) 4861da177e4SLinus Torvalds { 4871da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 48898310e58SDavid VomLehn u32 maxblock; 48998310e58SDavid VomLehn int bytes_filled; 4901da177e4SLinus Torvalds void *pgdata; 4911da177e4SLinus Torvalds 4921da177e4SLinus Torvalds maxblock = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 4931da177e4SLinus Torvalds bytes_filled = 0; 49498310e58SDavid VomLehn pgdata = kmap(page); 49598310e58SDavid VomLehn 4961da177e4SLinus Torvalds if (page->index < maxblock) { 4971da177e4SLinus Torvalds struct super_block *sb = inode->i_sb; 4981da177e4SLinus Torvalds u32 blkptr_offset = OFFSET(inode) + page->index*4; 4991da177e4SLinus Torvalds u32 start_offset, compr_len; 5001da177e4SLinus Torvalds 5011da177e4SLinus Torvalds start_offset = OFFSET(inode) + maxblock*4; 502353ab6e9SIngo Molnar mutex_lock(&read_mutex); 5031da177e4SLinus Torvalds if (page->index) 50498310e58SDavid VomLehn start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4, 50598310e58SDavid VomLehn 4); 50698310e58SDavid VomLehn compr_len = (*(u32 *) cramfs_read(sb, blkptr_offset, 4) - 50798310e58SDavid VomLehn start_offset); 508353ab6e9SIngo Molnar mutex_unlock(&read_mutex); 50998310e58SDavid VomLehn 5101da177e4SLinus Torvalds if (compr_len == 0) 5111da177e4SLinus Torvalds ; /* hole */ 51298310e58SDavid VomLehn else if (unlikely(compr_len > (PAGE_CACHE_SIZE << 1))) { 51398310e58SDavid VomLehn pr_err("cramfs: bad compressed blocksize %u\n", 51498310e58SDavid VomLehn compr_len); 51598310e58SDavid VomLehn goto err; 51698310e58SDavid VomLehn } else { 517353ab6e9SIngo Molnar mutex_lock(&read_mutex); 5181da177e4SLinus Torvalds bytes_filled = cramfs_uncompress_block(pgdata, 5191da177e4SLinus Torvalds PAGE_CACHE_SIZE, 5201da177e4SLinus Torvalds cramfs_read(sb, start_offset, compr_len), 5211da177e4SLinus Torvalds compr_len); 522353ab6e9SIngo Molnar mutex_unlock(&read_mutex); 52398310e58SDavid VomLehn if (unlikely(bytes_filled < 0)) 52498310e58SDavid VomLehn goto err; 5251da177e4SLinus Torvalds } 52698310e58SDavid VomLehn } 52798310e58SDavid VomLehn 5281da177e4SLinus Torvalds memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled); 5291da177e4SLinus Torvalds flush_dcache_page(page); 53098310e58SDavid VomLehn kunmap(page); 5311da177e4SLinus Torvalds SetPageUptodate(page); 5321da177e4SLinus Torvalds unlock_page(page); 5331da177e4SLinus Torvalds return 0; 53498310e58SDavid VomLehn 53598310e58SDavid VomLehn err: 53698310e58SDavid VomLehn kunmap(page); 53798310e58SDavid VomLehn ClearPageUptodate(page); 53898310e58SDavid VomLehn SetPageError(page); 53998310e58SDavid VomLehn unlock_page(page); 54098310e58SDavid VomLehn return 0; 5411da177e4SLinus Torvalds } 5421da177e4SLinus Torvalds 543f5e54d6eSChristoph Hellwig static const struct address_space_operations cramfs_aops = { 5441da177e4SLinus Torvalds .readpage = cramfs_readpage 5451da177e4SLinus Torvalds }; 5461da177e4SLinus Torvalds 5471da177e4SLinus Torvalds /* 5481da177e4SLinus Torvalds * Our operations: 5491da177e4SLinus Torvalds */ 5501da177e4SLinus Torvalds 5511da177e4SLinus Torvalds /* 5521da177e4SLinus Torvalds * A directory can only readdir 5531da177e4SLinus Torvalds */ 5544b6f5d20SArjan van de Ven static const struct file_operations cramfs_directory_operations = { 5551da177e4SLinus Torvalds .llseek = generic_file_llseek, 5561da177e4SLinus Torvalds .read = generic_read_dir, 5576f7f231eSAl Viro .iterate = cramfs_readdir, 5581da177e4SLinus Torvalds }; 5591da177e4SLinus Torvalds 560754661f1SArjan van de Ven static const struct inode_operations cramfs_dir_inode_operations = { 5611da177e4SLinus Torvalds .lookup = cramfs_lookup, 5621da177e4SLinus Torvalds }; 5631da177e4SLinus Torvalds 564ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations cramfs_ops = { 5651da177e4SLinus Torvalds .remount_fs = cramfs_remount, 5661da177e4SLinus Torvalds .statfs = cramfs_statfs, 5671da177e4SLinus Torvalds }; 5681da177e4SLinus Torvalds 569152a0836SAl Viro static struct dentry *cramfs_mount(struct file_system_type *fs_type, 570152a0836SAl Viro int flags, const char *dev_name, void *data) 5711da177e4SLinus Torvalds { 572152a0836SAl Viro return mount_bdev(fs_type, flags, dev_name, data, cramfs_fill_super); 5731da177e4SLinus Torvalds } 5741da177e4SLinus Torvalds 5751da177e4SLinus Torvalds static struct file_system_type cramfs_fs_type = { 5761da177e4SLinus Torvalds .owner = THIS_MODULE, 5771da177e4SLinus Torvalds .name = "cramfs", 578152a0836SAl Viro .mount = cramfs_mount, 5792309fb8eSAl Viro .kill_sb = cramfs_kill_sb, 5801da177e4SLinus Torvalds .fs_flags = FS_REQUIRES_DEV, 5811da177e4SLinus Torvalds }; 5827f78e035SEric W. Biederman MODULE_ALIAS_FS("cramfs"); 5831da177e4SLinus Torvalds 5841da177e4SLinus Torvalds static int __init init_cramfs_fs(void) 5851da177e4SLinus Torvalds { 58650d44ed0SAlexey Dobriyan int rv; 58750d44ed0SAlexey Dobriyan 58850d44ed0SAlexey Dobriyan rv = cramfs_uncompress_init(); 58950d44ed0SAlexey Dobriyan if (rv < 0) 59050d44ed0SAlexey Dobriyan return rv; 59150d44ed0SAlexey Dobriyan rv = register_filesystem(&cramfs_fs_type); 59250d44ed0SAlexey Dobriyan if (rv < 0) 59350d44ed0SAlexey Dobriyan cramfs_uncompress_exit(); 59450d44ed0SAlexey Dobriyan return rv; 5951da177e4SLinus Torvalds } 5961da177e4SLinus Torvalds 5971da177e4SLinus Torvalds static void __exit exit_cramfs_fs(void) 5981da177e4SLinus Torvalds { 5991da177e4SLinus Torvalds cramfs_uncompress_exit(); 6001da177e4SLinus Torvalds unregister_filesystem(&cramfs_fs_type); 6011da177e4SLinus Torvalds } 6021da177e4SLinus Torvalds 6031da177e4SLinus Torvalds module_init(init_cramfs_fs) 6041da177e4SLinus Torvalds module_exit(exit_cramfs_fs) 6051da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 606