aboutsummaryrefslogtreecommitdiffstats
path: root/fs/romfs/inode.c
diff options
context:
space:
mode:
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/romfs/inode.c
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/romfs/inode.c')
-rw-r--r--fs/romfs/inode.c665
1 files changed, 0 insertions, 665 deletions
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");
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-27 07:18:30 -0500