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authorDavid Howells <dhowells@redhat.com>2009-02-12 05:40:10 -0500
committerDavid Woodhouse <David.Woodhouse@intel.com>2009-03-24 05:01:32 -0400
commitda4458bda237aa0cb1688f6c359477f203788f6a (patch)
tree9b76cb1ecb462cccc8412eef2af5f18dcee77b51 /fs
parent6e232cfce35a20a8702d9ac7709d35030c1b3271 (diff)
NOMMU: Make it possible for RomFS to use MTD devices directly
Change RomFS so that it can use MTD devices directly - without the intercession of the block layer - as well as using block devices. This permits RomFS: (1) to use the MTD direct mapping facility available under NOMMU conditions if the underlying device is directly accessible by the CPU (including XIP); (2) and thus to be used when the block layer is disabled. RomFS can be configured with support just for MTD devices, just for Block devices or for both. If RomFS is configured for both, then it will treat mtdblock device files as MTD backing stores, not block layer backing stores. I tested this using a CONFIG_MMU=n CONFIG_BLOCK=n kernel running on my FRV board with a RomFS image installed on the mtdram test device. I see my test program being run XIP: # cat /proc/maps ... c0c000b0-c0c01f8c r-xs 00000000 1f:00 144 /mnt/doshm ... GDB on the kernel can be used to show that these addresses are within the set-aside RAM space. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Bernd Schmidt <bernd.schmidt@analog.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/romfs/Kconfig24
-rw-r--r--fs/romfs/Makefile9
-rw-r--r--fs/romfs/inode.c665
-rw-r--r--fs/romfs/internal.h47
-rw-r--r--fs/romfs/mmap-nommu.c75
-rw-r--r--fs/romfs/storage.c261
-rw-r--r--fs/romfs/super.c648
7 files changed, 1062 insertions, 667 deletions
diff --git a/fs/romfs/Kconfig b/fs/romfs/Kconfig
index 1a17020f9faf..802c742f002c 100644
--- a/fs/romfs/Kconfig
+++ b/fs/romfs/Kconfig
@@ -14,3 +14,27 @@ config ROMFS_FS
14 14
15 If you don't know whether you need it, then you don't need it: 15 If you don't know whether you need it, then you don't need it:
16 answer N. 16 answer N.
17
18config ROMFS_ON_BLOCK
19 bool "Block device-backed ROM file system support" if (ROMFS_ON_MTD && EMBEDDED)
20 depends on ROMFS_FS && BLOCK
21 help
22 This permits ROMFS to use block devices buffered through the page
23 cache as the medium from which to retrieve data. It does not allow
24 direct mapping of the medium.
25
26 If unsure, answer Y.
27
28config ROMFS_ON_MTD
29 bool "MTD-backed ROM file system support"
30 depends on ROMFS_FS
31 depends on MTD=y || (ROMFS_FS=m && MTD)
32 help
33 This permits ROMFS to use MTD based devices directly, without the
34 intercession of the block layer (which may have been disabled). It
35 also allows direct mapping of MTD devices through romfs files under
36 NOMMU conditions if the underlying device is directly addressable by
37 the CPU.
38
39 If unsure, answer Y.
40
diff --git a/fs/romfs/Makefile b/fs/romfs/Makefile
index c95b21cf49a3..420beb7d495c 100644
--- a/fs/romfs/Makefile
+++ b/fs/romfs/Makefile
@@ -1,7 +1,12 @@
1# 1#
2# Makefile for the linux romfs filesystem routines. 2# Makefile for the linux RomFS filesystem routines.
3# 3#
4 4
5obj-$(CONFIG_ROMFS_FS) += romfs.o 5obj-$(CONFIG_ROMFS_FS) += romfs.o
6 6
7romfs-objs := inode.o 7romfs-y := storage.o super.o
8
9ifneq ($(CONFIG_MMU),y)
10romfs-$(CONFIG_ROMFS_ON_MTD) += mmap-nommu.o
11endif
12
diff --git a/fs/romfs/inode.c b/fs/romfs/inode.c
deleted file mode 100644
index 98a232f7196b..000000000000
--- a/fs/romfs/inode.c
+++ /dev/null
@@ -1,665 +0,0 @@
1/*
2 * ROMFS file system, Linux implementation
3 *
4 * Copyright (C) 1997-1999 Janos Farkas <chexum@shadow.banki.hu>
5 *
6 * Using parts of the minix filesystem
7 * Copyright (C) 1991, 1992 Linus Torvalds
8 *
9 * and parts of the affs filesystem additionally
10 * Copyright (C) 1993 Ray Burr
11 * Copyright (C) 1996 Hans-Joachim Widmaier
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 *
18 * Changes
19 * Changed for 2.1.19 modules
20 * Jan 1997 Initial release
21 * Jun 1997 2.1.43+ changes
22 * Proper page locking in readpage
23 * Changed to work with 2.1.45+ fs
24 * Jul 1997 Fixed follow_link
25 * 2.1.47
26 * lookup shouldn't return -ENOENT
27 * from Horst von Brand:
28 * fail on wrong checksum
29 * double unlock_super was possible
30 * correct namelen for statfs
31 * spotted by Bill Hawes:
32 * readlink shouldn't iput()
33 * Jun 1998 2.1.106 from Avery Pennarun: glibc scandir()
34 * exposed a problem in readdir
35 * 2.1.107 code-freeze spellchecker run
36 * Aug 1998 2.1.118+ VFS changes
37 * Sep 1998 2.1.122 another VFS change (follow_link)
38 * Apr 1999 2.2.7 no more EBADF checking in
39 * lookup/readdir, use ERR_PTR
40 * Jun 1999 2.3.6 d_alloc_root use changed
41 * 2.3.9 clean up usage of ENOENT/negative
42 * dentries in lookup
43 * clean up page flags setting
44 * (error, uptodate, locking) in
45 * in readpage
46 * use init_special_inode for
47 * fifos/sockets (and streamline) in
48 * read_inode, fix _ops table order
49 * Aug 1999 2.3.16 __initfunc() => __init change
50 * Oct 1999 2.3.24 page->owner hack obsoleted
51 * Nov 1999 2.3.27 2.3.25+ page->offset => index change
52 */
53
54/* todo:
55 * - see Documentation/filesystems/romfs.txt
56 * - use allocated, not stack memory for file names?
57 * - considering write access...
58 * - network (tftp) files?
59 * - merge back some _op tables
60 */
61
62/*
63 * Sorry about some optimizations and for some goto's. I just wanted
64 * to squeeze some more bytes out of this code.. :)
65 */
66
67#include <linux/module.h>
68#include <linux/types.h>
69#include <linux/errno.h>
70#include <linux/slab.h>
71#include <linux/romfs_fs.h>
72#include <linux/fs.h>
73#include <linux/init.h>
74#include <linux/pagemap.h>
75#include <linux/smp_lock.h>
76#include <linux/buffer_head.h>
77#include <linux/vfs.h>
78
79#include <asm/uaccess.h>
80
81struct romfs_inode_info {
82 unsigned long i_metasize; /* size of non-data area */
83 unsigned long i_dataoffset; /* from the start of fs */
84 struct inode vfs_inode;
85};
86
87static struct inode *romfs_iget(struct super_block *, unsigned long);
88
89/* instead of private superblock data */
90static inline unsigned long romfs_maxsize(struct super_block *sb)
91{
92 return (unsigned long)sb->s_fs_info;
93}
94
95static inline struct romfs_inode_info *ROMFS_I(struct inode *inode)
96{
97 return container_of(inode, struct romfs_inode_info, vfs_inode);
98}
99
100static __u32
101romfs_checksum(void *data, int size)
102{
103 __u32 sum;
104 __be32 *ptr;
105
106 sum = 0; ptr = data;
107 size>>=2;
108 while (size>0) {
109 sum += be32_to_cpu(*ptr++);
110 size--;
111 }
112 return sum;
113}
114
115static const struct super_operations romfs_ops;
116
117static int romfs_fill_super(struct super_block *s, void *data, int silent)
118{
119 struct buffer_head *bh;
120 struct romfs_super_block *rsb;
121 struct inode *root;
122 int sz, ret = -EINVAL;
123
124 /* I would parse the options here, but there are none.. :) */
125
126 sb_set_blocksize(s, ROMBSIZE);
127 s->s_maxbytes = 0xFFFFFFFF;
128
129 bh = sb_bread(s, 0);
130 if (!bh) {
131 /* XXX merge with other printk? */
132 printk ("romfs: unable to read superblock\n");
133 goto outnobh;
134 }
135
136 rsb = (struct romfs_super_block *)bh->b_data;
137 sz = be32_to_cpu(rsb->size);
138 if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1
139 || sz < ROMFH_SIZE) {
140 if (!silent)
141 printk ("VFS: Can't find a romfs filesystem on dev "
142 "%s.\n", s->s_id);
143 goto out;
144 }
145 if (romfs_checksum(rsb, min_t(int, sz, 512))) {
146 printk ("romfs: bad initial checksum on dev "
147 "%s.\n", s->s_id);
148 goto out;
149 }
150
151 s->s_magic = ROMFS_MAGIC;
152 s->s_fs_info = (void *)(long)sz;
153
154 s->s_flags |= MS_RDONLY;
155
156 /* Find the start of the fs */
157 sz = (ROMFH_SIZE +
158 strnlen(rsb->name, ROMFS_MAXFN) + 1 + ROMFH_PAD)
159 & ROMFH_MASK;
160
161 s->s_op = &romfs_ops;
162 root = romfs_iget(s, sz);
163 if (IS_ERR(root)) {
164 ret = PTR_ERR(root);
165 goto out;
166 }
167
168 ret = -ENOMEM;
169 s->s_root = d_alloc_root(root);
170 if (!s->s_root)
171 goto outiput;
172
173 brelse(bh);
174 return 0;
175
176outiput:
177 iput(root);
178out:
179 brelse(bh);
180outnobh:
181 return ret;
182}
183
184/* That's simple too. */
185
186static int
187romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
188{
189 buf->f_type = ROMFS_MAGIC;
190 buf->f_bsize = ROMBSIZE;
191 buf->f_bfree = buf->f_bavail = buf->f_ffree;
192 buf->f_blocks = (romfs_maxsize(dentry->d_sb)+ROMBSIZE-1)>>ROMBSBITS;
193 buf->f_namelen = ROMFS_MAXFN;
194 return 0;
195}
196
197/* some helper routines */
198
199static int
200romfs_strnlen(struct inode *i, unsigned long offset, unsigned long count)
201{
202 struct buffer_head *bh;
203 unsigned long avail, maxsize, res;
204
205 maxsize = romfs_maxsize(i->i_sb);
206 if (offset >= maxsize)
207 return -1;
208
209 /* strnlen is almost always valid */
210 if (count > maxsize || offset+count > maxsize)
211 count = maxsize-offset;
212
213 bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
214 if (!bh)
215 return -1; /* error */
216
217 avail = ROMBSIZE - (offset & ROMBMASK);
218 maxsize = min_t(unsigned long, count, avail);
219 res = strnlen(((char *)bh->b_data)+(offset&ROMBMASK), maxsize);
220 brelse(bh);
221
222 if (res < maxsize)
223 return res; /* found all of it */
224
225 while (res < count) {
226 offset += maxsize;
227
228 bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
229 if (!bh)
230 return -1;
231 maxsize = min_t(unsigned long, count - res, ROMBSIZE);
232 avail = strnlen(bh->b_data, maxsize);
233 res += avail;
234 brelse(bh);
235 if (avail < maxsize)
236 return res;
237 }
238 return res;
239}
240
241static int
242romfs_copyfrom(struct inode *i, void *dest, unsigned long offset, unsigned long count)
243{
244 struct buffer_head *bh;
245 unsigned long avail, maxsize, res;
246
247 maxsize = romfs_maxsize(i->i_sb);
248 if (offset >= maxsize || count > maxsize || offset+count>maxsize)
249 return -1;
250
251 bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
252 if (!bh)
253 return -1; /* error */
254
255 avail = ROMBSIZE - (offset & ROMBMASK);
256 maxsize = min_t(unsigned long, count, avail);
257 memcpy(dest, ((char *)bh->b_data) + (offset & ROMBMASK), maxsize);
258 brelse(bh);
259
260 res = maxsize; /* all of it */
261
262 while (res < count) {
263 offset += maxsize;
264 dest += maxsize;
265
266 bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
267 if (!bh)
268 return -1;
269 maxsize = min_t(unsigned long, count - res, ROMBSIZE);
270 memcpy(dest, bh->b_data, maxsize);
271 brelse(bh);
272 res += maxsize;
273 }
274 return res;
275}
276
277static unsigned char romfs_dtype_table[] = {
278 DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO
279};
280
281static int
282romfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
283{
284 struct inode *i = filp->f_path.dentry->d_inode;
285 struct romfs_inode ri;
286 unsigned long offset, maxoff;
287 int j, ino, nextfh;
288 int stored = 0;
289 char fsname[ROMFS_MAXFN]; /* XXX dynamic? */
290
291 lock_kernel();
292
293 maxoff = romfs_maxsize(i->i_sb);
294
295 offset = filp->f_pos;
296 if (!offset) {
297 offset = i->i_ino & ROMFH_MASK;
298 if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
299 goto out;
300 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
301 }
302
303 /* Not really failsafe, but we are read-only... */
304 for(;;) {
305 if (!offset || offset >= maxoff) {
306 offset = maxoff;
307 filp->f_pos = offset;
308 goto out;
309 }
310 filp->f_pos = offset;
311
312 /* Fetch inode info */
313 if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
314 goto out;
315
316 j = romfs_strnlen(i, offset+ROMFH_SIZE, sizeof(fsname)-1);
317 if (j < 0)
318 goto out;
319
320 fsname[j]=0;
321 romfs_copyfrom(i, fsname, offset+ROMFH_SIZE, j);
322
323 ino = offset;
324 nextfh = be32_to_cpu(ri.next);
325 if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)
326 ino = be32_to_cpu(ri.spec);
327 if (filldir(dirent, fsname, j, offset, ino,
328 romfs_dtype_table[nextfh & ROMFH_TYPE]) < 0) {
329 goto out;
330 }
331 stored++;
332 offset = nextfh & ROMFH_MASK;
333 }
334out:
335 unlock_kernel();
336 return stored;
337}
338
339static struct dentry *
340romfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
341{
342 unsigned long offset, maxoff;
343 long res;
344 int fslen;
345 struct inode *inode = NULL;
346 char fsname[ROMFS_MAXFN]; /* XXX dynamic? */
347 struct romfs_inode ri;
348 const char *name; /* got from dentry */
349 int len;
350
351 res = -EACCES; /* placeholder for "no data here" */
352 offset = dir->i_ino & ROMFH_MASK;
353 lock_kernel();
354 if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
355 goto error;
356
357 maxoff = romfs_maxsize(dir->i_sb);
358 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
359
360 /* OK, now find the file whose name is in "dentry" in the
361 * directory specified by "dir". */
362
363 name = dentry->d_name.name;
364 len = dentry->d_name.len;
365
366 for(;;) {
367 if (!offset || offset >= maxoff)
368 goto success; /* negative success */
369 if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
370 goto error;
371
372 /* try to match the first 16 bytes of name */
373 fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, ROMFH_SIZE);
374 if (len < ROMFH_SIZE) {
375 if (len == fslen) {
376 /* both are shorter, and same size */
377 romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);
378 if (strncmp (name, fsname, len) == 0)
379 break;
380 }
381 } else if (fslen >= ROMFH_SIZE) {
382 /* both are longer; XXX optimize max size */
383 fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, sizeof(fsname)-1);
384 if (len == fslen) {
385 romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);
386 if (strncmp(name, fsname, len) == 0)
387 break;
388 }
389 }
390 /* next entry */
391 offset = be32_to_cpu(ri.next) & ROMFH_MASK;
392 }
393
394 /* Hard link handling */
395 if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
396 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
397
398 inode = romfs_iget(dir->i_sb, offset);
399 if (IS_ERR(inode)) {
400 res = PTR_ERR(inode);
401 goto error;
402 }
403
404success:
405 d_add(dentry, inode);
406 res = 0;
407error:
408 unlock_kernel();
409 return ERR_PTR(res);
410}
411
412/*
413 * Ok, we do readpage, to be able to execute programs. Unfortunately,
414 * we can't use bmap, since we may have looser alignments.
415 */
416
417static int
418romfs_readpage(struct file *file, struct page * page)
419{
420 struct inode *inode = page->mapping->host;
421 loff_t offset, size;
422 unsigned long filled;
423 void *buf;
424 int result = -EIO;
425
426 page_cache_get(page);
427 lock_kernel();
428 buf = kmap(page);
429 if (!buf)
430 goto err_out;
431
432 /* 32 bit warning -- but not for us :) */
433 offset = page_offset(page);
434 size = i_size_read(inode);
435 filled = 0;
436 result = 0;
437 if (offset < size) {
438 unsigned long readlen;
439
440 size -= offset;
441 readlen = size > PAGE_SIZE ? PAGE_SIZE : size;
442
443 filled = romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen);
444
445 if (filled != readlen) {
446 SetPageError(page);
447 filled = 0;
448 result = -EIO;
449 }
450 }
451
452 if (filled < PAGE_SIZE)
453 memset(buf + filled, 0, PAGE_SIZE-filled);
454
455 if (!result)
456 SetPageUptodate(page);
457 flush_dcache_page(page);
458
459 unlock_page(page);
460
461 kunmap(page);
462err_out:
463 page_cache_release(page);
464 unlock_kernel();
465
466 return result;
467}
468
469/* Mapping from our types to the kernel */
470
471static const struct address_space_operations romfs_aops = {
472 .readpage = romfs_readpage
473};
474
475static const struct file_operations romfs_dir_operations = {
476 .read = generic_read_dir,
477 .readdir = romfs_readdir,
478};
479
480static const struct inode_operations romfs_dir_inode_operations = {
481 .lookup = romfs_lookup,
482};
483
484static mode_t romfs_modemap[] =
485{
486 0, S_IFDIR+0644, S_IFREG+0644, S_IFLNK+0777,
487 S_IFBLK+0600, S_IFCHR+0600, S_IFSOCK+0644, S_IFIFO+0644
488};
489
490static struct inode *
491romfs_iget(struct super_block *sb, unsigned long ino)
492{
493 int nextfh, ret;
494 struct romfs_inode ri;
495 struct inode *i;
496
497 ino &= ROMFH_MASK;
498 i = iget_locked(sb, ino);
499 if (!i)
500 return ERR_PTR(-ENOMEM);
501 if (!(i->i_state & I_NEW))
502 return i;
503
504 i->i_mode = 0;
505
506 /* Loop for finding the real hard link */
507 for(;;) {
508 if (romfs_copyfrom(i, &ri, ino, ROMFH_SIZE) <= 0) {
509 printk(KERN_ERR "romfs: read error for inode 0x%lx\n",
510 ino);
511 iget_failed(i);
512 return ERR_PTR(-EIO);
513 }
514 /* XXX: do romfs_checksum here too (with name) */
515
516 nextfh = be32_to_cpu(ri.next);
517 if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
518 break;
519
520 ino = be32_to_cpu(ri.spec) & ROMFH_MASK;
521 }
522
523 i->i_nlink = 1; /* Hard to decide.. */
524 i->i_size = be32_to_cpu(ri.size);
525 i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0;
526 i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0;
527
528 /* Precalculate the data offset */
529 ret = romfs_strnlen(i, ino + ROMFH_SIZE, ROMFS_MAXFN);
530 if (ret >= 0)
531 ino = (ROMFH_SIZE + ret + 1 + ROMFH_PAD) & ROMFH_MASK;
532 else
533 ino = 0;
534
535 ROMFS_I(i)->i_metasize = ino;
536 ROMFS_I(i)->i_dataoffset = ino+(i->i_ino&ROMFH_MASK);
537
538 /* Compute permissions */
539 ino = romfs_modemap[nextfh & ROMFH_TYPE];
540 /* only "normal" files have ops */
541 switch (nextfh & ROMFH_TYPE) {
542 case 1:
543 i->i_size = ROMFS_I(i)->i_metasize;
544 i->i_op = &romfs_dir_inode_operations;
545 i->i_fop = &romfs_dir_operations;
546 if (nextfh & ROMFH_EXEC)
547 ino |= S_IXUGO;
548 i->i_mode = ino;
549 break;
550 case 2:
551 i->i_fop = &generic_ro_fops;
552 i->i_data.a_ops = &romfs_aops;
553 if (nextfh & ROMFH_EXEC)
554 ino |= S_IXUGO;
555 i->i_mode = ino;
556 break;
557 case 3:
558 i->i_op = &page_symlink_inode_operations;
559 i->i_data.a_ops = &romfs_aops;
560 i->i_mode = ino | S_IRWXUGO;
561 break;
562 default:
563 /* depending on MBZ for sock/fifos */
564 nextfh = be32_to_cpu(ri.spec);
565 init_special_inode(i, ino,
566 MKDEV(nextfh>>16,nextfh&0xffff));
567 }
568 unlock_new_inode(i);
569 return i;
570}
571
572static struct kmem_cache * romfs_inode_cachep;
573
574static struct inode *romfs_alloc_inode(struct super_block *sb)
575{
576 struct romfs_inode_info *ei;
577 ei = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL);
578 if (!ei)
579 return NULL;
580 return &ei->vfs_inode;
581}
582
583static void romfs_destroy_inode(struct inode *inode)
584{
585 kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode));
586}
587
588static void init_once(void *foo)
589{
590 struct romfs_inode_info *ei = foo;
591
592 inode_init_once(&ei->vfs_inode);
593}
594
595static int init_inodecache(void)
596{
597 romfs_inode_cachep = kmem_cache_create("romfs_inode_cache",
598 sizeof(struct romfs_inode_info),
599 0, (SLAB_RECLAIM_ACCOUNT|
600 SLAB_MEM_SPREAD),
601 init_once);
602 if (romfs_inode_cachep == NULL)
603 return -ENOMEM;
604 return 0;
605}
606
607static void destroy_inodecache(void)
608{
609 kmem_cache_destroy(romfs_inode_cachep);
610}
611
612static int romfs_remount(struct super_block *sb, int *flags, char *data)
613{
614 *flags |= MS_RDONLY;
615 return 0;
616}
617
618static const struct super_operations romfs_ops = {
619 .alloc_inode = romfs_alloc_inode,
620 .destroy_inode = romfs_destroy_inode,
621 .statfs = romfs_statfs,
622 .remount_fs = romfs_remount,
623};
624
625static int romfs_get_sb(struct file_system_type *fs_type,
626 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
627{
628 return get_sb_bdev(fs_type, flags, dev_name, data, romfs_fill_super,
629 mnt);
630}
631
632static struct file_system_type romfs_fs_type = {
633 .owner = THIS_MODULE,
634 .name = "romfs",
635 .get_sb = romfs_get_sb,
636 .kill_sb = kill_block_super,
637 .fs_flags = FS_REQUIRES_DEV,
638};
639
640static int __init init_romfs_fs(void)
641{
642 int err = init_inodecache();
643 if (err)
644 goto out1;
645 err = register_filesystem(&romfs_fs_type);
646 if (err)
647 goto out;
648 return 0;
649out:
650 destroy_inodecache();
651out1:
652 return err;
653}
654
655static void __exit exit_romfs_fs(void)
656{
657 unregister_filesystem(&romfs_fs_type);
658 destroy_inodecache();
659}
660
661/* Yes, works even as a module... :) */
662
663module_init(init_romfs_fs)
664module_exit(exit_romfs_fs)
665MODULE_LICENSE("GPL");
diff --git a/fs/romfs/internal.h b/fs/romfs/internal.h
new file mode 100644
index 000000000000..06044a9dc62d
--- /dev/null
+++ b/fs/romfs/internal.h
@@ -0,0 +1,47 @@
1/* RomFS internal definitions
2 *
3 * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/romfs_fs.h>
13
14struct romfs_inode_info {
15 struct inode vfs_inode;
16 unsigned long i_metasize; /* size of non-data area */
17 unsigned long i_dataoffset; /* from the start of fs */
18};
19
20static inline size_t romfs_maxsize(struct super_block *sb)
21{
22 return (size_t) (unsigned long) sb->s_fs_info;
23}
24
25static inline struct romfs_inode_info *ROMFS_I(struct inode *inode)
26{
27 return container_of(inode, struct romfs_inode_info, vfs_inode);
28}
29
30/*
31 * mmap-nommu.c
32 */
33#if !defined(CONFIG_MMU) && defined(CONFIG_ROMFS_ON_MTD)
34extern const struct file_operations romfs_ro_fops;
35#else
36#define romfs_ro_fops generic_ro_fops
37#endif
38
39/*
40 * storage.c
41 */
42extern int romfs_dev_read(struct super_block *sb, unsigned long pos,
43 void *buf, size_t buflen);
44extern ssize_t romfs_dev_strnlen(struct super_block *sb,
45 unsigned long pos, size_t maxlen);
46extern int romfs_dev_strncmp(struct super_block *sb, unsigned long pos,
47 const char *str, size_t size);
diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c
new file mode 100644
index 000000000000..f0511e816967
--- /dev/null
+++ b/fs/romfs/mmap-nommu.c
@@ -0,0 +1,75 @@
1/* NOMMU mmap support for RomFS on MTD devices
2 *
3 * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/mm.h>
13#include <linux/mtd/super.h>
14#include "internal.h"
15
16/*
17 * try to determine where a shared mapping can be made
18 * - only supported for NOMMU at the moment (MMU can't doesn't copy private
19 * mappings)
20 * - attempts to map through to the underlying MTD device
21 */
22static unsigned long romfs_get_unmapped_area(struct file *file,
23 unsigned long addr,
24 unsigned long len,
25 unsigned long pgoff,
26 unsigned long flags)
27{
28 struct inode *inode = file->f_mapping->host;
29 struct mtd_info *mtd = inode->i_sb->s_mtd;
30 unsigned long isize, offset;
31
32 if (!mtd)
33 goto cant_map_directly;
34
35 isize = i_size_read(inode);
36 offset = pgoff << PAGE_SHIFT;
37 if (offset > isize || len > isize || offset > isize - len)
38 return (unsigned long) -EINVAL;
39
40 /* we need to call down to the MTD layer to do the actual mapping */
41 if (mtd->get_unmapped_area) {
42 if (addr != 0)
43 return (unsigned long) -EINVAL;
44
45 if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
46 return (unsigned long) -EINVAL;
47
48 offset += ROMFS_I(inode)->i_dataoffset;
49 if (offset > mtd->size - len)
50 return (unsigned long) -EINVAL;
51
52 return mtd->get_unmapped_area(mtd, len, offset, flags);
53 }
54
55cant_map_directly:
56 return (unsigned long) -ENOSYS;
57}
58
59/*
60 * permit a R/O mapping to be made directly through onto an MTD device if
61 * possible
62 */
63static int romfs_mmap(struct file *file, struct vm_area_struct *vma)
64{
65 return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS;
66}
67
68const struct file_operations romfs_ro_fops = {
69 .llseek = generic_file_llseek,
70 .read = do_sync_read,
71 .aio_read = generic_file_aio_read,
72 .splice_read = generic_file_splice_read,
73 .mmap = romfs_mmap,
74 .get_unmapped_area = romfs_get_unmapped_area,
75};
diff --git a/fs/romfs/storage.c b/fs/romfs/storage.c
new file mode 100644
index 000000000000..7e3e1e12a081
--- /dev/null
+++ b/fs/romfs/storage.c
@@ -0,0 +1,261 @@
1/* RomFS storage access routines
2 *
3 * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/fs.h>
13#include <linux/mtd/super.h>
14#include <linux/buffer_head.h>
15#include "internal.h"
16
17#if !defined(CONFIG_ROMFS_ON_MTD) && !defined(CONFIG_ROMFS_ON_BLOCK)
18#error no ROMFS backing store interface configured
19#endif
20
21#ifdef CONFIG_ROMFS_ON_MTD
22#define ROMFS_MTD_READ(sb, ...) ((sb)->s_mtd->read((sb)->s_mtd, ##__VA_ARGS__))
23
24/*
25 * read data from an romfs image on an MTD device
26 */
27static int romfs_mtd_read(struct super_block *sb, unsigned long pos,
28 void *buf, size_t buflen)
29{
30 size_t rlen;
31 int ret;
32
33 ret = ROMFS_MTD_READ(sb, pos, buflen, &rlen, buf);
34 return (ret < 0 || rlen != buflen) ? -EIO : 0;
35}
36
37/*
38 * determine the length of a string in a romfs image on an MTD device
39 */
40static ssize_t romfs_mtd_strnlen(struct super_block *sb,
41 unsigned long pos, size_t maxlen)
42{
43 ssize_t n = 0;
44 size_t segment;
45 u_char buf[16], *p;
46 size_t len;
47 int ret;
48
49 /* scan the string up to 16 bytes at a time */
50 while (maxlen > 0) {
51 segment = min_t(size_t, maxlen, 16);
52 ret = ROMFS_MTD_READ(sb, pos, segment, &len, buf);
53 if (ret < 0)
54 return ret;
55 p = memchr(buf, 0, len);
56 if (p)
57 return n + (p - buf);
58 maxlen -= len;
59 pos += len;
60 n += len;
61 }
62
63 return n;
64}
65
66/*
67 * compare a string to one in a romfs image on MTD
68 * - return 1 if matched, 0 if differ, -ve if error
69 */
70static int romfs_mtd_strncmp(struct super_block *sb, unsigned long pos,
71 const char *str, size_t size)
72{
73 u_char buf[16];
74 size_t len, segment;
75 int ret;
76
77 /* scan the string up to 16 bytes at a time */
78 while (size > 0) {
79 segment = min_t(size_t, size, 16);
80 ret = ROMFS_MTD_READ(sb, pos, segment, &len, buf);
81 if (ret < 0)
82 return ret;
83 if (memcmp(buf, str, len) != 0)
84 return 0;
85 size -= len;
86 pos += len;
87 str += len;
88 }
89
90 return 1;
91}
92#endif /* CONFIG_ROMFS_ON_MTD */
93
94#ifdef CONFIG_ROMFS_ON_BLOCK
95/*
96 * read data from an romfs image on a block device
97 */
98static int romfs_blk_read(struct super_block *sb, unsigned long pos,
99 void *buf, size_t buflen)
100{
101 struct buffer_head *bh;
102 unsigned long offset;
103 size_t segment;
104
105 /* copy the string up to blocksize bytes at a time */
106 while (buflen > 0) {
107 offset = pos & (ROMBSIZE - 1);
108 segment = min_t(size_t, buflen, ROMBSIZE - offset);
109 bh = sb_bread(sb, pos >> ROMBSBITS);
110 if (!bh)
111 return -EIO;
112 memcpy(buf, bh->b_data + offset, segment);
113 brelse(bh);
114 buflen -= segment;
115 pos += segment;
116 }
117
118 return 0;
119}
120
121/*
122 * determine the length of a string in romfs on a block device
123 */
124static ssize_t romfs_blk_strnlen(struct super_block *sb,
125 unsigned long pos, size_t limit)
126{
127 struct buffer_head *bh;
128 unsigned long offset;
129 ssize_t n = 0;
130 size_t segment;
131 u_char *buf, *p;
132
133 /* scan the string up to blocksize bytes at a time */
134 while (limit > 0) {
135 offset = pos & (ROMBSIZE - 1);
136 segment = min_t(size_t, limit, ROMBSIZE - offset);
137 bh = sb_bread(sb, pos >> ROMBSBITS);
138 if (!bh)
139 return -EIO;
140 buf = bh->b_data + offset;
141 p = memchr(buf, 0, segment);
142 brelse(bh);
143 if (p)
144 return n + (p - buf);
145 limit -= segment;
146 pos += segment;
147 n += segment;
148 }
149
150 return n;
151}
152
153/*
154 * compare a string to one in a romfs image on a block device
155 * - return 1 if matched, 0 if differ, -ve if error
156 */
157static int romfs_blk_strncmp(struct super_block *sb, unsigned long pos,
158 const char *str, size_t size)
159{
160 struct buffer_head *bh;
161 unsigned long offset;
162 size_t segment;
163 bool x;
164
165 /* scan the string up to 16 bytes at a time */
166 while (size > 0) {
167 offset = pos & (ROMBSIZE - 1);
168 segment = min_t(size_t, size, ROMBSIZE - offset);
169 bh = sb_bread(sb, pos >> ROMBSBITS);
170 if (!bh)
171 return -EIO;
172 x = (memcmp(bh->b_data + offset, str, segment) != 0);
173 brelse(bh);
174 if (x)
175 return 0;
176 size -= segment;
177 pos += segment;
178 str += segment;
179 }
180
181 return 1;
182}
183#endif /* CONFIG_ROMFS_ON_BLOCK */
184
185/*
186 * read data from the romfs image
187 */
188int romfs_dev_read(struct super_block *sb, unsigned long pos,
189 void *buf, size_t buflen)
190{
191 size_t limit;
192
193 limit = romfs_maxsize(sb);
194 if (pos >= limit)
195 return -EIO;
196 if (buflen > limit - pos)
197 buflen = limit - pos;
198
199#ifdef CONFIG_ROMFS_ON_MTD
200 if (sb->s_mtd)
201 return romfs_mtd_read(sb, pos, buf, buflen);
202#endif
203#ifdef CONFIG_ROMFS_ON_BLOCK
204 if (sb->s_bdev)
205 return romfs_blk_read(sb, pos, buf, buflen);
206#endif
207 return -EIO;
208}
209
210/*
211 * determine the length of a string in romfs
212 */
213ssize_t romfs_dev_strnlen(struct super_block *sb,
214 unsigned long pos, size_t maxlen)
215{
216 size_t limit;
217
218 limit = romfs_maxsize(sb);
219 if (pos >= limit)
220 return -EIO;
221 if (maxlen > limit - pos)
222 maxlen = limit - pos;
223
224#ifdef CONFIG_ROMFS_ON_MTD
225 if (sb->s_mtd)
226 return romfs_mtd_strnlen(sb, pos, limit);
227#endif
228#ifdef CONFIG_ROMFS_ON_BLOCK
229 if (sb->s_bdev)
230 return romfs_blk_strnlen(sb, pos, limit);
231#endif
232 return -EIO;
233}
234
235/*
236 * compare a string to one in romfs
237 * - return 1 if matched, 0 if differ, -ve if error
238 */
239int romfs_dev_strncmp(struct super_block *sb, unsigned long pos,
240 const char *str, size_t size)
241{
242 size_t limit;
243
244 limit = romfs_maxsize(sb);
245 if (pos >= limit)
246 return -EIO;
247 if (size > ROMFS_MAXFN)
248 return -ENAMETOOLONG;
249 if (size > limit - pos)
250 return -EIO;
251
252#ifdef CONFIG_ROMFS_ON_MTD
253 if (sb->s_mtd)
254 return romfs_mtd_strncmp(sb, pos, str, size);
255#endif
256#ifdef CONFIG_ROMFS_ON_BLOCK
257 if (sb->s_bdev)
258 return romfs_blk_strncmp(sb, pos, str, size);
259#endif
260 return -EIO;
261}
diff --git a/fs/romfs/super.c b/fs/romfs/super.c
new file mode 100644
index 000000000000..1e548a4975ba
--- /dev/null
+++ b/fs/romfs/super.c
@@ -0,0 +1,648 @@
1/* Block- or MTD-based romfs
2 *
3 * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * Derived from: ROMFS file system, Linux implementation
7 *
8 * Copyright © 1997-1999 Janos Farkas <chexum@shadow.banki.hu>
9 *
10 * Using parts of the minix filesystem
11 * Copyright © 1991, 1992 Linus Torvalds
12 *
13 * and parts of the affs filesystem additionally
14 * Copyright © 1993 Ray Burr
15 * Copyright © 1996 Hans-Joachim Widmaier
16 *
17 * Changes
18 * Changed for 2.1.19 modules
19 * Jan 1997 Initial release
20 * Jun 1997 2.1.43+ changes
21 * Proper page locking in readpage
22 * Changed to work with 2.1.45+ fs
23 * Jul 1997 Fixed follow_link
24 * 2.1.47
25 * lookup shouldn't return -ENOENT
26 * from Horst von Brand:
27 * fail on wrong checksum
28 * double unlock_super was possible
29 * correct namelen for statfs
30 * spotted by Bill Hawes:
31 * readlink shouldn't iput()
32 * Jun 1998 2.1.106 from Avery Pennarun: glibc scandir()
33 * exposed a problem in readdir
34 * 2.1.107 code-freeze spellchecker run
35 * Aug 1998 2.1.118+ VFS changes
36 * Sep 1998 2.1.122 another VFS change (follow_link)
37 * Apr 1999 2.2.7 no more EBADF checking in
38 * lookup/readdir, use ERR_PTR
39 * Jun 1999 2.3.6 d_alloc_root use changed
40 * 2.3.9 clean up usage of ENOENT/negative
41 * dentries in lookup
42 * clean up page flags setting
43 * (error, uptodate, locking) in
44 * in readpage
45 * use init_special_inode for
46 * fifos/sockets (and streamline) in
47 * read_inode, fix _ops table order
48 * Aug 1999 2.3.16 __initfunc() => __init change
49 * Oct 1999 2.3.24 page->owner hack obsoleted
50 * Nov 1999 2.3.27 2.3.25+ page->offset => index change
51 *
52 *
53 * This program is free software; you can redistribute it and/or
54 * modify it under the terms of the GNU General Public Licence
55 * as published by the Free Software Foundation; either version
56 * 2 of the Licence, or (at your option) any later version.
57 */
58
59#include <linux/module.h>
60#include <linux/string.h>
61#include <linux/fs.h>
62#include <linux/time.h>
63#include <linux/slab.h>
64#include <linux/init.h>
65#include <linux/blkdev.h>
66#include <linux/parser.h>
67#include <linux/mount.h>
68#include <linux/namei.h>
69#include <linux/statfs.h>
70#include <linux/mtd/super.h>
71#include <linux/ctype.h>
72#include <linux/highmem.h>
73#include <linux/pagemap.h>
74#include <linux/uaccess.h>
75#include "internal.h"
76
77static struct kmem_cache *romfs_inode_cachep;
78
79static const umode_t romfs_modemap[8] = {
80 0, /* hard link */
81 S_IFDIR | 0644, /* directory */
82 S_IFREG | 0644, /* regular file */
83 S_IFLNK | 0777, /* symlink */
84 S_IFBLK | 0600, /* blockdev */
85 S_IFCHR | 0600, /* chardev */
86 S_IFSOCK | 0644, /* socket */
87 S_IFIFO | 0644 /* FIFO */
88};
89
90static const unsigned char romfs_dtype_table[] = {
91 DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO
92};
93
94static struct inode *romfs_iget(struct super_block *sb, unsigned long pos);
95
96/*
97 * read a page worth of data from the image
98 */
99static int romfs_readpage(struct file *file, struct page *page)
100{
101 struct inode *inode = page->mapping->host;
102 loff_t offset, size;
103 unsigned long fillsize, pos;
104 void *buf;
105 int ret;
106
107 buf = kmap(page);
108 if (!buf)
109 return -ENOMEM;
110
111 /* 32 bit warning -- but not for us :) */
112 offset = page_offset(page);
113 size = i_size_read(inode);
114 fillsize = 0;
115 ret = 0;
116 if (offset < size) {
117 size -= offset;
118 fillsize = size > PAGE_SIZE ? PAGE_SIZE : size;
119
120 pos = ROMFS_I(inode)->i_dataoffset + offset;
121
122 ret = romfs_dev_read(inode->i_sb, pos, buf, fillsize);
123 if (ret < 0) {
124 SetPageError(page);
125 fillsize = 0;
126 ret = -EIO;
127 }
128 }
129
130 if (fillsize < PAGE_SIZE)
131 memset(buf + fillsize, 0, PAGE_SIZE - fillsize);
132 if (ret == 0)
133 SetPageUptodate(page);
134
135 flush_dcache_page(page);
136 kunmap(page);
137 unlock_page(page);
138 return ret;
139}
140
141static const struct address_space_operations romfs_aops = {
142 .readpage = romfs_readpage
143};
144
145/*
146 * read the entries from a directory
147 */
148static int romfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
149{
150 struct inode *i = filp->f_dentry->d_inode;
151 struct romfs_inode ri;
152 unsigned long offset, maxoff;
153 int j, ino, nextfh;
154 int stored = 0;
155 char fsname[ROMFS_MAXFN]; /* XXX dynamic? */
156 int ret;
157
158 maxoff = romfs_maxsize(i->i_sb);
159
160 offset = filp->f_pos;
161 if (!offset) {
162 offset = i->i_ino & ROMFH_MASK;
163 ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE);
164 if (ret < 0)
165 goto out;
166 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
167 }
168
169 /* Not really failsafe, but we are read-only... */
170 for (;;) {
171 if (!offset || offset >= maxoff) {
172 offset = maxoff;
173 filp->f_pos = offset;
174 goto out;
175 }
176 filp->f_pos = offset;
177
178 /* Fetch inode info */
179 ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE);
180 if (ret < 0)
181 goto out;
182
183 j = romfs_dev_strnlen(i->i_sb, offset + ROMFH_SIZE,
184 sizeof(fsname) - 1);
185 if (j < 0)
186 goto out;
187
188 ret = romfs_dev_read(i->i_sb, offset + ROMFH_SIZE, fsname, j);
189 if (ret < 0)
190 goto out;
191 fsname[j] = '\0';
192
193 ino = offset;
194 nextfh = be32_to_cpu(ri.next);
195 if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)
196 ino = be32_to_cpu(ri.spec);
197 if (filldir(dirent, fsname, j, offset, ino,
198 romfs_dtype_table[nextfh & ROMFH_TYPE]) < 0)
199 goto out;
200
201 stored++;
202 offset = nextfh & ROMFH_MASK;
203 }
204
205out:
206 return stored;
207}
208
209/*
210 * look up an entry in a directory
211 */
212static struct dentry *romfs_lookup(struct inode *dir, struct dentry *dentry,
213 struct nameidata *nd)
214{
215 unsigned long offset, maxoff;
216 struct inode *inode;
217 struct romfs_inode ri;
218 const char *name; /* got from dentry */
219 int len, ret;
220
221 offset = dir->i_ino & ROMFH_MASK;
222 ret = romfs_dev_read(dir->i_sb, offset, &ri, ROMFH_SIZE);
223 if (ret < 0)
224 goto error;
225
226 /* search all the file entries in the list starting from the one
227 * pointed to by the directory's special data */
228 maxoff = romfs_maxsize(dir->i_sb);
229 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
230
231 name = dentry->d_name.name;
232 len = dentry->d_name.len;
233
234 for (;;) {
235 if (!offset || offset >= maxoff)
236 goto out0;
237
238 ret = romfs_dev_read(dir->i_sb, offset, &ri, sizeof(ri));
239 if (ret < 0)
240 goto error;
241
242 /* try to match the first 16 bytes of name */
243 ret = romfs_dev_strncmp(dir->i_sb, offset + ROMFH_SIZE, name,
244 len);
245 if (ret < 0)
246 goto error;
247 if (ret == 1)
248 break;
249
250 /* next entry */
251 offset = be32_to_cpu(ri.next) & ROMFH_MASK;
252 }
253
254 /* Hard link handling */
255 if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
256 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
257
258 inode = romfs_iget(dir->i_sb, offset);
259 if (IS_ERR(inode)) {
260 ret = PTR_ERR(inode);
261 goto error;
262 }
263 goto outi;
264
265 /*
266 * it's a bit funky, _lookup needs to return an error code
267 * (negative) or a NULL, both as a dentry. ENOENT should not
268 * be returned, instead we need to create a negative dentry by
269 * d_add(dentry, NULL); and return 0 as no error.
270 * (Although as I see, it only matters on writable file
271 * systems).
272 */
273out0:
274 inode = NULL;
275outi:
276 d_add(dentry, inode);
277 ret = 0;
278error:
279 return ERR_PTR(ret);
280}
281
282static const struct file_operations romfs_dir_operations = {
283 .read = generic_read_dir,
284 .readdir = romfs_readdir,
285};
286
287static struct inode_operations romfs_dir_inode_operations = {
288 .lookup = romfs_lookup,
289};
290
291/*
292 * get a romfs inode based on its position in the image (which doubles as the
293 * inode number)
294 */
295static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)
296{
297 struct romfs_inode_info *inode;
298 struct romfs_inode ri;
299 struct inode *i;
300 unsigned long nlen;
301 unsigned nextfh, ret;
302 umode_t mode;
303
304 /* we might have to traverse a chain of "hard link" file entries to get
305 * to the actual file */
306 for (;;) {
307 ret = romfs_dev_read(sb, pos, &ri, sizeof(ri));
308 if (ret < 0)
309 goto error;
310
311 /* XXX: do romfs_checksum here too (with name) */
312
313 nextfh = be32_to_cpu(ri.next);
314 if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
315 break;
316
317 pos = be32_to_cpu(ri.spec) & ROMFH_MASK;
318 }
319
320 /* determine the length of the filename */
321 nlen = romfs_dev_strnlen(sb, pos + ROMFH_SIZE, ROMFS_MAXFN);
322 if (IS_ERR_VALUE(nlen))
323 goto eio;
324
325 /* get an inode for this image position */
326 i = iget_locked(sb, pos);
327 if (!i)
328 return ERR_PTR(-ENOMEM);
329
330 if (!(i->i_state & I_NEW))
331 return i;
332
333 /* precalculate the data offset */
334 inode = ROMFS_I(i);
335 inode->i_metasize = (ROMFH_SIZE + nlen + 1 + ROMFH_PAD) & ROMFH_MASK;
336 inode->i_dataoffset = pos + inode->i_metasize;
337
338 i->i_nlink = 1; /* Hard to decide.. */
339 i->i_size = be32_to_cpu(ri.size);
340 i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0;
341 i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0;
342
343 /* set up mode and ops */
344 mode = romfs_modemap[nextfh & ROMFH_TYPE];
345
346 switch (nextfh & ROMFH_TYPE) {
347 case ROMFH_DIR:
348 i->i_size = ROMFS_I(i)->i_metasize;
349 i->i_op = &romfs_dir_inode_operations;
350 i->i_fop = &romfs_dir_operations;
351 if (nextfh & ROMFH_EXEC)
352 mode |= S_IXUGO;
353 break;
354 case ROMFH_REG:
355 i->i_fop = &romfs_ro_fops;
356 i->i_data.a_ops = &romfs_aops;
357 if (i->i_sb->s_mtd)
358 i->i_data.backing_dev_info =
359 i->i_sb->s_mtd->backing_dev_info;
360 if (nextfh & ROMFH_EXEC)
361 mode |= S_IXUGO;
362 break;
363 case ROMFH_SYM:
364 i->i_op = &page_symlink_inode_operations;
365 i->i_data.a_ops = &romfs_aops;
366 mode |= S_IRWXUGO;
367 break;
368 default:
369 /* depending on MBZ for sock/fifos */
370 nextfh = be32_to_cpu(ri.spec);
371 init_special_inode(i, mode, MKDEV(nextfh >> 16,
372 nextfh & 0xffff));
373 break;
374 }
375
376 i->i_mode = mode;
377
378 unlock_new_inode(i);
379 return i;
380
381eio:
382 ret = -EIO;
383error:
384 printk(KERN_ERR "ROMFS: read error for inode 0x%lx\n", pos);
385 return ERR_PTR(ret);
386}
387
388/*
389 * allocate a new inode
390 */
391static struct inode *romfs_alloc_inode(struct super_block *sb)
392{
393 struct romfs_inode_info *inode;
394 inode = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL);
395 return inode ? &inode->vfs_inode : NULL;
396}
397
398/*
399 * return a spent inode to the slab cache
400 */
401static void romfs_destroy_inode(struct inode *inode)
402{
403 kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode));
404}
405
406/*
407 * get filesystem statistics
408 */
409static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
410{
411 buf->f_type = ROMFS_MAGIC;
412 buf->f_namelen = ROMFS_MAXFN;
413 buf->f_bsize = ROMBSIZE;
414 buf->f_bfree = buf->f_bavail = buf->f_ffree;
415 buf->f_blocks =
416 (romfs_maxsize(dentry->d_sb) + ROMBSIZE - 1) >> ROMBSBITS;
417 return 0;
418}
419
420/*
421 * remounting must involve read-only
422 */
423static int romfs_remount(struct super_block *sb, int *flags, char *data)
424{
425 *flags |= MS_RDONLY;
426 return 0;
427}
428
429static const struct super_operations romfs_super_ops = {
430 .alloc_inode = romfs_alloc_inode,
431 .destroy_inode = romfs_destroy_inode,
432 .statfs = romfs_statfs,
433 .remount_fs = romfs_remount,
434};
435
436/*
437 * checksum check on part of a romfs filesystem
438 */
439static __u32 romfs_checksum(const void *data, int size)
440{
441 const __be32 *ptr = data;
442 __u32 sum;
443
444 sum = 0;
445 size >>= 2;
446 while (size > 0) {
447 sum += be32_to_cpu(*ptr++);
448 size--;
449 }
450 return sum;
451}
452
453/*
454 * fill in the superblock
455 */
456static int romfs_fill_super(struct super_block *sb, void *data, int silent)
457{
458 struct romfs_super_block *rsb;
459 struct inode *root;
460 unsigned long pos, img_size;
461 const char *storage;
462 size_t len;
463 int ret;
464
465#ifdef CONFIG_BLOCK
466 if (!sb->s_mtd) {
467 sb_set_blocksize(sb, ROMBSIZE);
468 } else {
469 sb->s_blocksize = ROMBSIZE;
470 sb->s_blocksize_bits = blksize_bits(ROMBSIZE);
471 }
472#endif
473
474 sb->s_maxbytes = 0xFFFFFFFF;
475 sb->s_magic = ROMFS_MAGIC;
476 sb->s_flags |= MS_RDONLY | MS_NOATIME;
477 sb->s_op = &romfs_super_ops;
478
479 /* read the image superblock and check it */
480 rsb = kmalloc(512, GFP_KERNEL);
481 if (!rsb)
482 return -ENOMEM;
483
484 sb->s_fs_info = (void *) 512;
485 ret = romfs_dev_read(sb, 0, rsb, 512);
486 if (ret < 0)
487 goto error_rsb;
488
489 img_size = be32_to_cpu(rsb->size);
490
491 if (sb->s_mtd && img_size > sb->s_mtd->size)
492 goto error_rsb_inval;
493
494 sb->s_fs_info = (void *) img_size;
495
496 if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 ||
497 img_size < ROMFH_SIZE) {
498 if (!silent)
499 printk(KERN_WARNING "VFS:"
500 " Can't find a romfs filesystem on dev %s.\n",
501 sb->s_id);
502 goto error_rsb_inval;
503 }
504
505 if (romfs_checksum(rsb, min_t(size_t, img_size, 512))) {
506 printk(KERN_ERR "ROMFS: bad initial checksum on dev %s.\n",
507 sb->s_id);
508 goto error_rsb_inval;
509 }
510
511 storage = sb->s_mtd ? "MTD" : "the block layer";
512
513 len = strnlen(rsb->name, ROMFS_MAXFN);
514 if (!silent)
515 printk(KERN_NOTICE "ROMFS: Mounting image '%*.*s' through %s\n",
516 (unsigned) len, (unsigned) len, rsb->name, storage);
517
518 kfree(rsb);
519 rsb = NULL;
520
521 /* find the root directory */
522 pos = (ROMFH_SIZE + len + 1 + ROMFH_PAD) & ROMFH_MASK;
523
524 root = romfs_iget(sb, pos);
525 if (!root)
526 goto error;
527
528 sb->s_root = d_alloc_root(root);
529 if (!sb->s_root)
530 goto error_i;
531
532 return 0;
533
534error_i:
535 iput(root);
536error:
537 return -EINVAL;
538error_rsb_inval:
539 ret = -EINVAL;
540error_rsb:
541 return ret;
542}
543
544/*
545 * get a superblock for mounting
546 */
547static int romfs_get_sb(struct file_system_type *fs_type,
548 int flags, const char *dev_name,
549 void *data, struct vfsmount *mnt)
550{
551 int ret = -EINVAL;
552
553#ifdef CONFIG_ROMFS_ON_MTD
554 ret = get_sb_mtd(fs_type, flags, dev_name, data, romfs_fill_super,
555 mnt);
556#endif
557#ifdef CONFIG_ROMFS_ON_BLOCK
558 if (ret == -EINVAL)
559 ret = get_sb_bdev(fs_type, flags, dev_name, data,
560 romfs_fill_super, mnt);
561#endif
562 return ret;
563}
564
565/*
566 * destroy a romfs superblock in the appropriate manner
567 */
568static void romfs_kill_sb(struct super_block *sb)
569{
570#ifdef CONFIG_ROMFS_ON_MTD
571 if (sb->s_mtd) {
572 kill_mtd_super(sb);
573 return;
574 }
575#endif
576#ifdef CONFIG_ROMFS_ON_BLOCK
577 if (sb->s_bdev) {
578 kill_block_super(sb);
579 return;
580 }
581#endif
582}
583
584static struct file_system_type romfs_fs_type = {
585 .owner = THIS_MODULE,
586 .name = "romfs",
587 .get_sb = romfs_get_sb,
588 .kill_sb = romfs_kill_sb,
589 .fs_flags = FS_REQUIRES_DEV,
590};
591
592/*
593 * inode storage initialiser
594 */
595static void romfs_i_init_once(void *_inode)
596{
597 struct romfs_inode_info *inode = _inode;
598
599 inode_init_once(&inode->vfs_inode);
600}
601
602/*
603 * romfs module initialisation
604 */
605static int __init init_romfs_fs(void)
606{
607 int ret;
608
609 printk(KERN_INFO "ROMFS MTD (C) 2007 Red Hat, Inc.\n");
610
611 romfs_inode_cachep =
612 kmem_cache_create("romfs_i",
613 sizeof(struct romfs_inode_info), 0,
614 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
615 romfs_i_init_once);
616
617 if (!romfs_inode_cachep) {
618 printk(KERN_ERR
619 "ROMFS error: Failed to initialise inode cache\n");
620 return -ENOMEM;
621 }
622 ret = register_filesystem(&romfs_fs_type);
623 if (ret) {
624 printk(KERN_ERR "ROMFS error: Failed to register filesystem\n");
625 goto error_register;
626 }
627 return 0;
628
629error_register:
630 kmem_cache_destroy(romfs_inode_cachep);
631 return ret;
632}
633
634/*
635 * romfs module removal
636 */
637static void __exit exit_romfs_fs(void)
638{
639 unregister_filesystem(&romfs_fs_type);
640 kmem_cache_destroy(romfs_inode_cachep);
641}
642
643module_init(init_romfs_fs);
644module_exit(exit_romfs_fs);
645
646MODULE_DESCRIPTION("Direct-MTD Capable RomFS");
647MODULE_AUTHOR("Red Hat, Inc.");
648MODULE_LICENSE("GPL"); /* Actually dual-licensed, but it doesn't matter for */
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-29 03:16:41 -0500