blob: 3a32ddf98095faad5f56d2332ab35ef110e90e58 [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
Fabian Frederick4f21e1e2014-08-08 14:22:50 -070014#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/module.h>
17#include <linux/fs.h>
18#include <linux/pagemap.h>
19#include <linux/init.h>
20#include <linux/string.h>
21#include <linux/blkdev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/slab.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>
Al Virof7f4f4d2013-12-10 16:54:28 -050025#include <uapi/linux/cramfs_fs.h>
Fabian Frederick1508f3eb2014-08-08 14:22:55 -070026#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
Al Virof7f4f4d2013-12-10 16:54:28 -050028#include "internal.h"
29
30/*
31 * cramfs super-block data in memory
32 */
33struct cramfs_sb_info {
34 unsigned long magic;
35 unsigned long size;
36 unsigned long blocks;
37 unsigned long files;
38 unsigned long flags;
39};
40
41static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
42{
43 return sb->s_fs_info;
44}
45
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -080046static const struct super_operations cramfs_ops;
Arjan van de Ven754661f2007-02-12 00:55:38 -080047static const struct inode_operations cramfs_dir_inode_operations;
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080048static const struct file_operations cramfs_directory_operations;
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070049static const struct address_space_operations cramfs_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Ingo Molnar353ab6e2006-03-26 01:37:12 -080051static DEFINE_MUTEX(read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53
Stefani Seibold6f772fe2011-01-12 17:01:10 -080054/* These macros may change in future, to provide better st_ino semantics. */
Linus Torvalds1da177e2005-04-16 15:20:36 -070055#define OFFSET(x) ((x)->i_ino)
56
Al Viro0577d1b2011-07-17 19:04:14 -040057static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070058{
Stefani Seibold6f772fe2011-01-12 17:01:10 -080059 if (!cino->offset)
60 return offset + 1;
61 if (!cino->size)
62 return offset + 1;
63
64 /*
65 * The file mode test fixes buggy mkcramfs implementations where
66 * cramfs_inode->offset is set to a non zero value for entries
67 * which did not contain data, like devices node and fifos.
68 */
69 switch (cino->mode & S_IFMT) {
70 case S_IFREG:
71 case S_IFDIR:
72 case S_IFLNK:
73 return cino->offset << 2;
74 default:
75 break;
76 }
77 return offset + 1;
78}
79
80static struct inode *get_cramfs_inode(struct super_block *sb,
Al Viro0577d1b2011-07-17 19:04:14 -040081 const struct cramfs_inode *cramfs_inode, unsigned int offset)
Stefani Seibold6f772fe2011-01-12 17:01:10 -080082{
83 struct inode *inode;
Al Viro77b8a752010-06-04 21:19:01 -040084 static struct timespec zerotime;
Stefani Seibold6f772fe2011-01-12 17:01:10 -080085
86 inode = iget_locked(sb, cramino(cramfs_inode, offset));
87 if (!inode)
88 return ERR_PTR(-ENOMEM);
89 if (!(inode->i_state & I_NEW))
90 return inode;
91
92 switch (cramfs_inode->mode & S_IFMT) {
93 case S_IFREG:
94 inode->i_fop = &generic_ro_fops;
95 inode->i_data.a_ops = &cramfs_aops;
96 break;
97 case S_IFDIR:
98 inode->i_op = &cramfs_dir_inode_operations;
99 inode->i_fop = &cramfs_directory_operations;
100 break;
101 case S_IFLNK:
102 inode->i_op = &page_symlink_inode_operations;
Al Viro21fc61c2015-11-17 01:07:57 -0500103 inode_nohighmem(inode);
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800104 inode->i_data.a_ops = &cramfs_aops;
105 break;
106 default:
107 init_special_inode(inode, cramfs_inode->mode,
108 old_decode_dev(cramfs_inode->size));
109 }
110
Al Viro77b8a752010-06-04 21:19:01 -0400111 inode->i_mode = cramfs_inode->mode;
Eric W. Biedermana7d9cfe2012-02-10 11:06:08 -0800112 i_uid_write(inode, cramfs_inode->uid);
113 i_gid_write(inode, cramfs_inode->gid);
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800114
115 /* if the lower 2 bits are zero, the inode contains data */
116 if (!(inode->i_ino & 3)) {
117 inode->i_size = cramfs_inode->size;
118 inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
119 }
120
Al Viro77b8a752010-06-04 21:19:01 -0400121 /* Struct copy intentional */
122 inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
123 /* inode->i_nlink is left 1 - arguably wrong for directories,
124 but it's the best we can do without reading the directory
125 contents. 1 yields the right result in GNU find, even
126 without -noleaf option. */
Dave Johnsona97c9bf2005-09-06 15:17:40 -0700127
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800128 unlock_new_inode(inode);
129
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 return inode;
131}
132
133/*
134 * We have our own block cache: don't fill up the buffer cache
135 * with the rom-image, because the way the filesystem is set
136 * up the accesses should be fairly regular and cached in the
137 * page cache and dentry tree anyway..
138 *
139 * This also acts as a way to guarantee contiguous areas of up to
Kirill A. Shutemovea1754a2016-04-01 15:29:48 +0300140 * BLKS_PER_BUF*PAGE_SIZE, so that the caller doesn't need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 * worry about end-of-buffer issues even when decompressing a full
142 * page cache.
143 */
144#define READ_BUFFERS (2)
145/* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */
146#define NEXT_BUFFER(_ix) ((_ix) ^ 1)
147
148/*
149 * BLKS_PER_BUF_SHIFT should be at least 2 to allow for "compressed"
150 * data that takes up more space than the original and with unlucky
151 * alignment.
152 */
153#define BLKS_PER_BUF_SHIFT (2)
154#define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT)
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300155#define BUFFER_SIZE (BLKS_PER_BUF*PAGE_SIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156
157static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE];
158static unsigned buffer_blocknr[READ_BUFFERS];
Fabian Frederick31d92e52014-08-08 14:22:52 -0700159static struct super_block *buffer_dev[READ_BUFFERS];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160static int next_buffer;
161
162/*
163 * Returns a pointer to a buffer containing at least LEN bytes of
164 * filesystem starting at byte offset OFFSET into the filesystem.
165 */
166static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned int len)
167{
168 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
169 struct page *pages[BLKS_PER_BUF];
Andi Drebes6bbfb072007-10-18 03:06:54 -0700170 unsigned i, blocknr, buffer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 unsigned long devsize;
172 char *data;
173
174 if (!len)
175 return NULL;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300176 blocknr = offset >> PAGE_SHIFT;
177 offset &= PAGE_SIZE - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
179 /* Check if an existing buffer already has the data.. */
180 for (i = 0; i < READ_BUFFERS; i++) {
181 unsigned int blk_offset;
182
183 if (buffer_dev[i] != sb)
184 continue;
185 if (blocknr < buffer_blocknr[i])
186 continue;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300187 blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 blk_offset += offset;
189 if (blk_offset + len > BUFFER_SIZE)
190 continue;
191 return read_buffers[i] + blk_offset;
192 }
193
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300194 devsize = mapping->host->i_size >> PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
196 /* Ok, read in BLKS_PER_BUF pages completely first. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 for (i = 0; i < BLKS_PER_BUF; i++) {
198 struct page *page = NULL;
199
200 if (blocknr + i < devsize) {
Sasha Levin67f9fd92014-04-03 14:48:18 -0700201 page = read_mapping_page(mapping, blocknr + i, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 /* synchronous error? */
203 if (IS_ERR(page))
204 page = NULL;
205 }
206 pages[i] = page;
207 }
208
209 for (i = 0; i < BLKS_PER_BUF; i++) {
210 struct page *page = pages[i];
Fabian Frederick31d92e52014-08-08 14:22:52 -0700211
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 if (page) {
213 wait_on_page_locked(page);
214 if (!PageUptodate(page)) {
215 /* asynchronous error */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300216 put_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 pages[i] = NULL;
218 }
219 }
220 }
221
222 buffer = next_buffer;
223 next_buffer = NEXT_BUFFER(buffer);
224 buffer_blocknr[buffer] = blocknr;
225 buffer_dev[buffer] = sb;
226
227 data = read_buffers[buffer];
228 for (i = 0; i < BLKS_PER_BUF; i++) {
229 struct page *page = pages[i];
Fabian Frederick31d92e52014-08-08 14:22:52 -0700230
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 if (page) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300232 memcpy(data, kmap(page), PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 kunmap(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300234 put_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 } else
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300236 memset(data, 0, PAGE_SIZE);
237 data += PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 }
239 return read_buffers[buffer] + offset;
240}
241
Al Viro2309fb82013-12-10 16:35:14 -0500242static void cramfs_kill_sb(struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243{
Al Virof7f4f4d2013-12-10 16:54:28 -0500244 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
Fabian Frederick31d92e52014-08-08 14:22:52 -0700245
Al Viro2309fb82013-12-10 16:35:14 -0500246 kill_block_super(sb);
247 kfree(sbi);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248}
249
250static int cramfs_remount(struct super_block *sb, int *flags, char *data)
251{
Theodore Ts'o02b99842014-03-13 10:14:33 -0400252 sync_filesystem(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 *flags |= MS_RDONLY;
254 return 0;
255}
256
257static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
258{
259 int i;
260 struct cramfs_super super;
261 unsigned long root_offset;
262 struct cramfs_sb_info *sbi;
263 struct inode *root;
264
265 sb->s_flags |= MS_RDONLY;
266
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -0700267 sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 if (!sbi)
269 return -ENOMEM;
270 sb->s_fs_info = sbi;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
272 /* Invalidate the read buffers on mount: think disk change.. */
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800273 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 for (i = 0; i < READ_BUFFERS; i++)
275 buffer_blocknr[i] = -1;
276
277 /* Read the first block and get the superblock from it */
278 memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super));
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800279 mutex_unlock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
281 /* Do sanity checks on the superblock */
282 if (super.magic != CRAMFS_MAGIC) {
Masanari Iida0cc785e2012-02-11 21:35:12 +0900283 /* check for wrong endianness */
Andi Drebesac8d35c2007-10-16 23:27:12 -0700284 if (super.magic == CRAMFS_MAGIC_WEND) {
285 if (!silent)
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700286 pr_err("wrong endianness\n");
Al Viro2309fb82013-12-10 16:35:14 -0500287 return -EINVAL;
Andi Drebesac8d35c2007-10-16 23:27:12 -0700288 }
289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 /* check at 512 byte offset */
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800291 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super));
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800293 mutex_unlock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 if (super.magic != CRAMFS_MAGIC) {
Andi Drebesac8d35c2007-10-16 23:27:12 -0700295 if (super.magic == CRAMFS_MAGIC_WEND && !silent)
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700296 pr_err("wrong endianness\n");
Andi Drebesac8d35c2007-10-16 23:27:12 -0700297 else if (!silent)
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700298 pr_err("wrong magic\n");
Al Viro2309fb82013-12-10 16:35:14 -0500299 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 }
301 }
302
303 /* get feature flags first */
304 if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700305 pr_err("unsupported filesystem features\n");
Al Viro2309fb82013-12-10 16:35:14 -0500306 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 }
308
309 /* Check that the root inode is in a sane state */
310 if (!S_ISDIR(super.root.mode)) {
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700311 pr_err("root is not a directory\n");
Al Viro2309fb82013-12-10 16:35:14 -0500312 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 }
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800314 /* correct strange, hard-coded permissions of mkcramfs */
315 super.root.mode |= (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
316
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 root_offset = super.root.offset << 2;
318 if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) {
Fabian Frederick31d92e52014-08-08 14:22:52 -0700319 sbi->size = super.size;
320 sbi->blocks = super.fsid.blocks;
321 sbi->files = super.fsid.files;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 } else {
Fabian Frederick31d92e52014-08-08 14:22:52 -0700323 sbi->size = 1<<28;
324 sbi->blocks = 0;
325 sbi->files = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 }
Fabian Frederick31d92e52014-08-08 14:22:52 -0700327 sbi->magic = super.magic;
328 sbi->flags = super.flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 if (root_offset == 0)
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700330 pr_info("empty filesystem");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
332 ((root_offset != sizeof(struct cramfs_super)) &&
333 (root_offset != 512 + sizeof(struct cramfs_super))))
334 {
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700335 pr_err("bad root offset %lu\n", root_offset);
Al Viro2309fb82013-12-10 16:35:14 -0500336 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 }
338
339 /* Set it all up.. */
340 sb->s_op = &cramfs_ops;
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800341 root = get_cramfs_inode(sb, &super.root, 0);
Al Viro0577d1b2011-07-17 19:04:14 -0400342 if (IS_ERR(root))
Al Viro2309fb82013-12-10 16:35:14 -0500343 return PTR_ERR(root);
Al Viro48fde702012-01-08 22:15:13 -0500344 sb->s_root = d_make_root(root);
345 if (!sb->s_root)
Al Viro2309fb82013-12-10 16:35:14 -0500346 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348}
349
David Howells726c3342006-06-23 02:02:58 -0700350static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351{
David Howells726c3342006-06-23 02:02:58 -0700352 struct super_block *sb = dentry->d_sb;
Coly Li94ea77a2009-04-02 16:59:33 -0700353 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
David Howells726c3342006-06-23 02:02:58 -0700354
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 buf->f_type = CRAMFS_MAGIC;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300356 buf->f_bsize = PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 buf->f_blocks = CRAMFS_SB(sb)->blocks;
358 buf->f_bfree = 0;
359 buf->f_bavail = 0;
360 buf->f_files = CRAMFS_SB(sb)->files;
361 buf->f_ffree = 0;
Coly Li94ea77a2009-04-02 16:59:33 -0700362 buf->f_fsid.val[0] = (u32)id;
363 buf->f_fsid.val[1] = (u32)(id >> 32);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 buf->f_namelen = CRAMFS_MAXPATHLEN;
365 return 0;
366}
367
368/*
369 * Read a cramfs directory entry.
370 */
Al Viro6f7f2312013-05-17 18:02:17 -0400371static int cramfs_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372{
Al Viro6f7f2312013-05-17 18:02:17 -0400373 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 struct super_block *sb = inode->i_sb;
375 char *buf;
376 unsigned int offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
378 /* Offset within the thing. */
Al Viro6f7f2312013-05-17 18:02:17 -0400379 if (ctx->pos >= inode->i_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 return 0;
Al Viro6f7f2312013-05-17 18:02:17 -0400381 offset = ctx->pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 /* Directory entries are always 4-byte aligned */
383 if (offset & 3)
384 return -EINVAL;
385
Andi Drebes4176ed52007-10-18 03:06:55 -0700386 buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 if (!buf)
388 return -ENOMEM;
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 while (offset < inode->i_size) {
391 struct cramfs_inode *de;
392 unsigned long nextoffset;
393 char *name;
394 ino_t ino;
Al Viro175a4eb2011-07-26 03:30:54 -0400395 umode_t mode;
Al Viro6f7f2312013-05-17 18:02:17 -0400396 int namelen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800398 mutex_lock(&read_mutex);
Andi Drebes4176ed52007-10-18 03:06:55 -0700399 de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 name = (char *)(de+1);
401
402 /*
403 * Namelengths on disk are shifted by two
404 * and the name padded out to 4-byte boundaries
405 * with zeroes.
406 */
407 namelen = de->namelen << 2;
408 memcpy(buf, name, namelen);
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800409 ino = cramino(de, OFFSET(inode) + offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 mode = de->mode;
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800411 mutex_unlock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 nextoffset = offset + sizeof(*de) + namelen;
413 for (;;) {
414 if (!namelen) {
415 kfree(buf);
416 return -EIO;
417 }
418 if (buf[namelen-1])
419 break;
420 namelen--;
421 }
Al Viro6f7f2312013-05-17 18:02:17 -0400422 if (!dir_emit(ctx, buf, namelen, ino, mode >> 12))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 break;
424
Al Viro6f7f2312013-05-17 18:02:17 -0400425 ctx->pos = offset = nextoffset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 }
427 kfree(buf);
428 return 0;
429}
430
431/*
432 * Lookup and fill in the inode data..
433 */
Fabian Frederick31d92e52014-08-08 14:22:52 -0700434static struct dentry *cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435{
436 unsigned int offset = 0;
Al Viro0577d1b2011-07-17 19:04:14 -0400437 struct inode *inode = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 int sorted;
439
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800440 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS;
442 while (offset < dir->i_size) {
443 struct cramfs_inode *de;
444 char *name;
445 int namelen, retval;
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800446 int dir_off = OFFSET(dir) + offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447
Stefani Seibold6f772fe2011-01-12 17:01:10 -0800448 de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 name = (char *)(de+1);
450
451 /* Try to take advantage of sorted directories */
452 if (sorted && (dentry->d_name.name[0] < name[0]))
453 break;
454
455 namelen = de->namelen << 2;
456 offset += sizeof(*de) + namelen;
457
458 /* Quick check that the name is roughly the right length */
459 if (((dentry->d_name.len + 3) & ~3) != namelen)
460 continue;
461
462 for (;;) {
463 if (!namelen) {
Al Viro0577d1b2011-07-17 19:04:14 -0400464 inode = ERR_PTR(-EIO);
465 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 }
467 if (name[namelen-1])
468 break;
469 namelen--;
470 }
471 if (namelen != dentry->d_name.len)
472 continue;
473 retval = memcmp(dentry->d_name.name, name, namelen);
474 if (retval > 0)
475 continue;
476 if (!retval) {
Al Viro0577d1b2011-07-17 19:04:14 -0400477 inode = get_cramfs_inode(dir->i_sb, de, dir_off);
478 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 }
480 /* else (retval < 0) */
481 if (sorted)
482 break;
483 }
Al Viro0577d1b2011-07-17 19:04:14 -0400484out:
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800485 mutex_unlock(&read_mutex);
Al Viro0577d1b2011-07-17 19:04:14 -0400486 if (IS_ERR(inode))
487 return ERR_CAST(inode);
488 d_add(dentry, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 return NULL;
490}
491
Fabian Frederick31d92e52014-08-08 14:22:52 -0700492static int cramfs_readpage(struct file *file, struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493{
494 struct inode *inode = page->mapping->host;
David VomLehn98310e52009-04-02 16:59:15 -0700495 u32 maxblock;
496 int bytes_filled;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 void *pgdata;
498
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300499 maxblock = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 bytes_filled = 0;
David VomLehn98310e52009-04-02 16:59:15 -0700501 pgdata = kmap(page);
502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 if (page->index < maxblock) {
504 struct super_block *sb = inode->i_sb;
505 u32 blkptr_offset = OFFSET(inode) + page->index*4;
506 u32 start_offset, compr_len;
507
508 start_offset = OFFSET(inode) + maxblock*4;
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800509 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 if (page->index)
David VomLehn98310e52009-04-02 16:59:15 -0700511 start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4,
512 4);
513 compr_len = (*(u32 *) cramfs_read(sb, blkptr_offset, 4) -
514 start_offset);
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800515 mutex_unlock(&read_mutex);
David VomLehn98310e52009-04-02 16:59:15 -0700516
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 if (compr_len == 0)
518 ; /* hole */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300519 else if (unlikely(compr_len > (PAGE_SIZE << 1))) {
Fabian Frederick4f21e1e2014-08-08 14:22:50 -0700520 pr_err("bad compressed blocksize %u\n",
David VomLehn98310e52009-04-02 16:59:15 -0700521 compr_len);
522 goto err;
523 } else {
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800524 mutex_lock(&read_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 bytes_filled = cramfs_uncompress_block(pgdata,
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300526 PAGE_SIZE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 cramfs_read(sb, start_offset, compr_len),
528 compr_len);
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800529 mutex_unlock(&read_mutex);
David VomLehn98310e52009-04-02 16:59:15 -0700530 if (unlikely(bytes_filled < 0))
531 goto err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 }
David VomLehn98310e52009-04-02 16:59:15 -0700533 }
534
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300535 memset(pgdata + bytes_filled, 0, PAGE_SIZE - bytes_filled);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 flush_dcache_page(page);
David VomLehn98310e52009-04-02 16:59:15 -0700537 kunmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 SetPageUptodate(page);
539 unlock_page(page);
540 return 0;
David VomLehn98310e52009-04-02 16:59:15 -0700541
542err:
543 kunmap(page);
544 ClearPageUptodate(page);
545 SetPageError(page);
546 unlock_page(page);
547 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548}
549
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700550static const struct address_space_operations cramfs_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 .readpage = cramfs_readpage
552};
553
554/*
555 * Our operations:
556 */
557
558/*
559 * A directory can only readdir
560 */
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800561static const struct file_operations cramfs_directory_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 .llseek = generic_file_llseek,
563 .read = generic_read_dir,
Al Viro6f7f2312013-05-17 18:02:17 -0400564 .iterate = cramfs_readdir,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565};
566
Arjan van de Ven754661f2007-02-12 00:55:38 -0800567static const struct inode_operations cramfs_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 .lookup = cramfs_lookup,
569};
570
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800571static const struct super_operations cramfs_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 .remount_fs = cramfs_remount,
573 .statfs = cramfs_statfs,
574};
575
Al Viro152a0832010-07-25 00:46:55 +0400576static struct dentry *cramfs_mount(struct file_system_type *fs_type,
577 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578{
Al Viro152a0832010-07-25 00:46:55 +0400579 return mount_bdev(fs_type, flags, dev_name, data, cramfs_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580}
581
582static struct file_system_type cramfs_fs_type = {
583 .owner = THIS_MODULE,
584 .name = "cramfs",
Al Viro152a0832010-07-25 00:46:55 +0400585 .mount = cramfs_mount,
Al Viro2309fb82013-12-10 16:35:14 -0500586 .kill_sb = cramfs_kill_sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 .fs_flags = FS_REQUIRES_DEV,
588};
Eric W. Biederman7f78e032013-03-02 19:39:14 -0800589MODULE_ALIAS_FS("cramfs");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590
591static int __init init_cramfs_fs(void)
592{
Alexey Dobriyan50d44ed2006-09-29 02:01:04 -0700593 int rv;
594
595 rv = cramfs_uncompress_init();
596 if (rv < 0)
597 return rv;
598 rv = register_filesystem(&cramfs_fs_type);
599 if (rv < 0)
600 cramfs_uncompress_exit();
601 return rv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602}
603
604static void __exit exit_cramfs_fs(void)
605{
606 cramfs_uncompress_exit();
607 unregister_filesystem(&cramfs_fs_type);
608}
609
610module_init(init_cramfs_fs)
611module_exit(exit_cramfs_fs)
612MODULE_LICENSE("GPL");