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14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/module.h>
17#include <linux/fs.h>
18#include <linux/file.h>
19#include <linux/pagemap.h>
20#include <linux/pfn_t.h>
21#include <linux/ramfs.h>
22#include <linux/init.h>
23#include <linux/string.h>
24#include <linux/blkdev.h>
25#include <linux/mtd/mtd.h>
26#include <linux/mtd/super.h>
27#include <linux/slab.h>
28#include <linux/vfs.h>
29#include <linux/mutex.h>
30#include <uapi/linux/cramfs_fs.h>
31#include <linux/uaccess.h>
32
33#include "internal.h"
34
35
36
37
38struct cramfs_sb_info {
39 unsigned long magic;
40 unsigned long size;
41 unsigned long blocks;
42 unsigned long files;
43 unsigned long flags;
44 void *linear_virt_addr;
45 resource_size_t linear_phys_addr;
46 size_t mtd_point_size;
47};
48
49static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
50{
51 return sb->s_fs_info;
52}
53
54static const struct super_operations cramfs_ops;
55static const struct inode_operations cramfs_dir_inode_operations;
56static const struct file_operations cramfs_directory_operations;
57static const struct file_operations cramfs_physmem_fops;
58static const struct address_space_operations cramfs_aops;
59
60static DEFINE_MUTEX(read_mutex);
61
62
63
64#define OFFSET(x) ((x)->i_ino)
65
66static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset)
67{
68 if (!cino->offset)
69 return offset + 1;
70 if (!cino->size)
71 return offset + 1;
72
73
74
75
76
77
78 switch (cino->mode & S_IFMT) {
79 case S_IFREG:
80 case S_IFDIR:
81 case S_IFLNK:
82 return cino->offset << 2;
83 default:
84 break;
85 }
86 return offset + 1;
87}
88
89static struct inode *get_cramfs_inode(struct super_block *sb,
90 const struct cramfs_inode *cramfs_inode, unsigned int offset)
91{
92 struct inode *inode;
93 static struct timespec64 zerotime;
94
95 inode = iget_locked(sb, cramino(cramfs_inode, offset));
96 if (!inode)
97 return ERR_PTR(-ENOMEM);
98 if (!(inode->i_state & I_NEW))
99 return inode;
100
101 switch (cramfs_inode->mode & S_IFMT) {
102 case S_IFREG:
103 inode->i_fop = &generic_ro_fops;
104 inode->i_data.a_ops = &cramfs_aops;
105 if (IS_ENABLED(CONFIG_CRAMFS_MTD) &&
106 CRAMFS_SB(sb)->flags & CRAMFS_FLAG_EXT_BLOCK_POINTERS &&
107 CRAMFS_SB(sb)->linear_phys_addr)
108 inode->i_fop = &cramfs_physmem_fops;
109 break;
110 case S_IFDIR:
111 inode->i_op = &cramfs_dir_inode_operations;
112 inode->i_fop = &cramfs_directory_operations;
113 break;
114 case S_IFLNK:
115 inode->i_op = &page_symlink_inode_operations;
116 inode_nohighmem(inode);
117 inode->i_data.a_ops = &cramfs_aops;
118 break;
119 default:
120 init_special_inode(inode, cramfs_inode->mode,
121 old_decode_dev(cramfs_inode->size));
122 }
123
124 inode->i_mode = cramfs_inode->mode;
125 i_uid_write(inode, cramfs_inode->uid);
126 i_gid_write(inode, cramfs_inode->gid);
127
128
129 if (!(inode->i_ino & 3)) {
130 inode->i_size = cramfs_inode->size;
131 inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
132 }
133
134
135 inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
136
137
138
139
140
141 unlock_new_inode(inode);
142
143 return inode;
144}
145
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157
158
159
160#define READ_BUFFERS (2)
161
162#define NEXT_BUFFER(_ix) ((_ix) ^ 1)
163
164
165
166
167
168
169#define BLKS_PER_BUF_SHIFT (2)
170#define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT)
171#define BUFFER_SIZE (BLKS_PER_BUF*PAGE_SIZE)
172
173static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE];
174static unsigned buffer_blocknr[READ_BUFFERS];
175static struct super_block *buffer_dev[READ_BUFFERS];
176static int next_buffer;
177
178
179
180
181static void *cramfs_blkdev_read(struct super_block *sb, unsigned int offset,
182 unsigned int len)
183{
184 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
185 struct page *pages[BLKS_PER_BUF];
186 unsigned i, blocknr, buffer;
187 unsigned long devsize;
188 char *data;
189
190 if (!len)
191 return NULL;
192 blocknr = offset >> PAGE_SHIFT;
193 offset &= PAGE_SIZE - 1;
194
195
196 for (i = 0; i < READ_BUFFERS; i++) {
197 unsigned int blk_offset;
198
199 if (buffer_dev[i] != sb)
200 continue;
201 if (blocknr < buffer_blocknr[i])
202 continue;
203 blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_SHIFT;
204 blk_offset += offset;
205 if (blk_offset > BUFFER_SIZE ||
206 blk_offset + len > BUFFER_SIZE)
207 continue;
208 return read_buffers[i] + blk_offset;
209 }
210
211 devsize = mapping->host->i_size >> PAGE_SHIFT;
212
213
214 for (i = 0; i < BLKS_PER_BUF; i++) {
215 struct page *page = NULL;
216
217 if (blocknr + i < devsize) {
218 page = read_mapping_page(mapping, blocknr + i, NULL);
219
220 if (IS_ERR(page))
221 page = NULL;
222 }
223 pages[i] = page;
224 }
225
226 for (i = 0; i < BLKS_PER_BUF; i++) {
227 struct page *page = pages[i];
228
229 if (page) {
230 wait_on_page_locked(page);
231 if (!PageUptodate(page)) {
232
233 put_page(page);
234 pages[i] = NULL;
235 }
236 }
237 }
238
239 buffer = next_buffer;
240 next_buffer = NEXT_BUFFER(buffer);
241 buffer_blocknr[buffer] = blocknr;
242 buffer_dev[buffer] = sb;
243
244 data = read_buffers[buffer];
245 for (i = 0; i < BLKS_PER_BUF; i++) {
246 struct page *page = pages[i];
247
248 if (page) {
249 memcpy(data, kmap(page), PAGE_SIZE);
250 kunmap(page);
251 put_page(page);
252 } else
253 memset(data, 0, PAGE_SIZE);
254 data += PAGE_SIZE;
255 }
256 return read_buffers[buffer] + offset;
257}
258
259
260
261
262static void *cramfs_direct_read(struct super_block *sb, unsigned int offset,
263 unsigned int len)
264{
265 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
266
267 if (!len)
268 return NULL;
269 if (len > sbi->size || offset > sbi->size - len)
270 return page_address(ZERO_PAGE(0));
271 return sbi->linear_virt_addr + offset;
272}
273
274
275
276
277
278static void *cramfs_read(struct super_block *sb, unsigned int offset,
279 unsigned int len)
280{
281 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
282
283 if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sbi->linear_virt_addr)
284 return cramfs_direct_read(sb, offset, len);
285 else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
286 return cramfs_blkdev_read(sb, offset, len);
287 else
288 return NULL;
289}
290
291
292
293
294
295
296static u32 cramfs_get_block_range(struct inode *inode, u32 pgoff, u32 *pages)
297{
298 struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
299 int i;
300 u32 *blockptrs, first_block_addr;
301
302
303
304
305
306
307 blockptrs = (u32 *)(sbi->linear_virt_addr + OFFSET(inode) + pgoff * 4);
308 first_block_addr = blockptrs[0] & ~CRAMFS_BLK_FLAGS;
309 i = 0;
310 do {
311 u32 block_off = i * (PAGE_SIZE >> CRAMFS_BLK_DIRECT_PTR_SHIFT);
312 u32 expect = (first_block_addr + block_off) |
313 CRAMFS_BLK_FLAG_DIRECT_PTR |
314 CRAMFS_BLK_FLAG_UNCOMPRESSED;
315 if (blockptrs[i] != expect) {
316 pr_debug("range: block %d/%d got %#x expects %#x\n",
317 pgoff+i, pgoff + *pages - 1,
318 blockptrs[i], expect);
319 if (i == 0)
320 return 0;
321 break;
322 }
323 } while (++i < *pages);
324
325 *pages = i;
326 return first_block_addr << CRAMFS_BLK_DIRECT_PTR_SHIFT;
327}
328
329#ifdef CONFIG_MMU
330
331
332
333
334
335
336
337static bool cramfs_last_page_is_shared(struct inode *inode)
338{
339 struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
340 u32 partial, last_page, blockaddr, *blockptrs;
341 char *tail_data;
342
343 partial = offset_in_page(inode->i_size);
344 if (!partial)
345 return false;
346 last_page = inode->i_size >> PAGE_SHIFT;
347 blockptrs = (u32 *)(sbi->linear_virt_addr + OFFSET(inode));
348 blockaddr = blockptrs[last_page] & ~CRAMFS_BLK_FLAGS;
349 blockaddr <<= CRAMFS_BLK_DIRECT_PTR_SHIFT;
350 tail_data = sbi->linear_virt_addr + blockaddr + partial;
351 return memchr_inv(tail_data, 0, PAGE_SIZE - partial) ? true : false;
352}
353
354static int cramfs_physmem_mmap(struct file *file, struct vm_area_struct *vma)
355{
356 struct inode *inode = file_inode(file);
357 struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
358 unsigned int pages, max_pages, offset;
359 unsigned long address, pgoff = vma->vm_pgoff;
360 char *bailout_reason;
361 int ret;
362
363 ret = generic_file_readonly_mmap(file, vma);
364 if (ret)
365 return ret;
366
367
368
369
370
371
372
373 bailout_reason = "vma is writable";
374 if (vma->vm_flags & VM_WRITE)
375 goto bailout;
376
377 max_pages = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
378 bailout_reason = "beyond file limit";
379 if (pgoff >= max_pages)
380 goto bailout;
381 pages = min(vma_pages(vma), max_pages - pgoff);
382
383 offset = cramfs_get_block_range(inode, pgoff, &pages);
384 bailout_reason = "unsuitable block layout";
385 if (!offset)
386 goto bailout;
387 address = sbi->linear_phys_addr + offset;
388 bailout_reason = "data is not page aligned";
389 if (!PAGE_ALIGNED(address))
390 goto bailout;
391
392
393 if (pgoff + pages == max_pages && cramfs_last_page_is_shared(inode)) {
394 pr_debug("mmap: %s: last page is shared\n",
395 file_dentry(file)->d_name.name);
396 pages--;
397 }
398
399 if (!pages) {
400 bailout_reason = "no suitable block remaining";
401 goto bailout;
402 }
403
404 if (pages == vma_pages(vma)) {
405
406
407
408
409
410
411 ret = remap_pfn_range(vma, vma->vm_start, address >> PAGE_SHIFT,
412 pages * PAGE_SIZE, vma->vm_page_prot);
413 } else {
414
415
416
417
418
419 int i;
420 vma->vm_flags |= VM_MIXEDMAP;
421 for (i = 0; i < pages && !ret; i++) {
422 vm_fault_t vmf;
423 unsigned long off = i * PAGE_SIZE;
424 pfn_t pfn = phys_to_pfn_t(address + off, PFN_DEV);
425 vmf = vmf_insert_mixed(vma, vma->vm_start + off, pfn);
426 if (vmf & VM_FAULT_ERROR)
427 ret = vm_fault_to_errno(vmf, 0);
428 }
429 }
430
431 if (!ret)
432 pr_debug("mapped %s[%lu] at 0x%08lx (%u/%lu pages) "
433 "to vma 0x%08lx, page_prot 0x%llx\n",
434 file_dentry(file)->d_name.name, pgoff,
435 address, pages, vma_pages(vma), vma->vm_start,
436 (unsigned long long)pgprot_val(vma->vm_page_prot));
437 return ret;
438
439bailout:
440 pr_debug("%s[%lu]: direct mmap impossible: %s\n",
441 file_dentry(file)->d_name.name, pgoff, bailout_reason);
442
443 return 0;
444}
445
446#else
447
448static int cramfs_physmem_mmap(struct file *file, struct vm_area_struct *vma)
449{
450 return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS;
451}
452
453static unsigned long cramfs_physmem_get_unmapped_area(struct file *file,
454 unsigned long addr, unsigned long len,
455 unsigned long pgoff, unsigned long flags)
456{
457 struct inode *inode = file_inode(file);
458 struct super_block *sb = inode->i_sb;
459 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
460 unsigned int pages, block_pages, max_pages, offset;
461
462 pages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
463 max_pages = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
464 if (pgoff >= max_pages || pages > max_pages - pgoff)
465 return -EINVAL;
466 block_pages = pages;
467 offset = cramfs_get_block_range(inode, pgoff, &block_pages);
468 if (!offset || block_pages != pages)
469 return -ENOSYS;
470 addr = sbi->linear_phys_addr + offset;
471 pr_debug("get_unmapped for %s ofs %#lx siz %lu at 0x%08lx\n",
472 file_dentry(file)->d_name.name, pgoff*PAGE_SIZE, len, addr);
473 return addr;
474}
475
476static unsigned int cramfs_physmem_mmap_capabilities(struct file *file)
477{
478 return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT |
479 NOMMU_MAP_READ | NOMMU_MAP_EXEC;
480}
481
482#endif
483
484static const struct file_operations cramfs_physmem_fops = {
485 .llseek = generic_file_llseek,
486 .read_iter = generic_file_read_iter,
487 .splice_read = generic_file_splice_read,
488 .mmap = cramfs_physmem_mmap,
489#ifndef CONFIG_MMU
490 .get_unmapped_area = cramfs_physmem_get_unmapped_area,
491 .mmap_capabilities = cramfs_physmem_mmap_capabilities,
492#endif
493};
494
495static void cramfs_kill_sb(struct super_block *sb)
496{
497 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
498
499 if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sb->s_mtd) {
500 if (sbi && sbi->mtd_point_size)
501 mtd_unpoint(sb->s_mtd, 0, sbi->mtd_point_size);
502 kill_mtd_super(sb);
503 } else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV) && sb->s_bdev) {
504 kill_block_super(sb);
505 }
506 kfree(sbi);
507}
508
509static int cramfs_remount(struct super_block *sb, int *flags, char *data)
510{
511 sync_filesystem(sb);
512 *flags |= SB_RDONLY;
513 return 0;
514}
515
516static int cramfs_read_super(struct super_block *sb,
517 struct cramfs_super *super, int silent)
518{
519 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
520 unsigned long root_offset;
521
522
523 sbi->size = PAGE_SIZE;
524
525
526 mutex_lock(&read_mutex);
527 memcpy(super, cramfs_read(sb, 0, sizeof(*super)), sizeof(*super));
528 mutex_unlock(&read_mutex);
529
530
531 if (super->magic != CRAMFS_MAGIC) {
532
533 if (super->magic == CRAMFS_MAGIC_WEND) {
534 if (!silent)
535 pr_err("wrong endianness\n");
536 return -EINVAL;
537 }
538
539
540 mutex_lock(&read_mutex);
541 memcpy(super,
542 cramfs_read(sb, 512, sizeof(*super)),
543 sizeof(*super));
544 mutex_unlock(&read_mutex);
545 if (super->magic != CRAMFS_MAGIC) {
546 if (super->magic == CRAMFS_MAGIC_WEND && !silent)
547 pr_err("wrong endianness\n");
548 else if (!silent)
549 pr_err("wrong magic\n");
550 return -EINVAL;
551 }
552 }
553
554
555 if (super->flags & ~CRAMFS_SUPPORTED_FLAGS) {
556 pr_err("unsupported filesystem features\n");
557 return -EINVAL;
558 }
559
560
561 if (!S_ISDIR(super->root.mode)) {
562 pr_err("root is not a directory\n");
563 return -EINVAL;
564 }
565
566 super->root.mode |= 0555;
567
568 root_offset = super->root.offset << 2;
569 if (super->flags & CRAMFS_FLAG_FSID_VERSION_2) {
570 sbi->size = super->size;
571 sbi->blocks = super->fsid.blocks;
572 sbi->files = super->fsid.files;
573 } else {
574 sbi->size = 1<<28;
575 sbi->blocks = 0;
576 sbi->files = 0;
577 }
578 sbi->magic = super->magic;
579 sbi->flags = super->flags;
580 if (root_offset == 0)
581 pr_info("empty filesystem");
582 else if (!(super->flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
583 ((root_offset != sizeof(struct cramfs_super)) &&
584 (root_offset != 512 + sizeof(struct cramfs_super))))
585 {
586 pr_err("bad root offset %lu\n", root_offset);
587 return -EINVAL;
588 }
589
590 return 0;
591}
592
593static int cramfs_finalize_super(struct super_block *sb,
594 struct cramfs_inode *cramfs_root)
595{
596 struct inode *root;
597
598
599 sb->s_flags |= SB_RDONLY;
600 sb->s_op = &cramfs_ops;
601 root = get_cramfs_inode(sb, cramfs_root, 0);
602 if (IS_ERR(root))
603 return PTR_ERR(root);
604 sb->s_root = d_make_root(root);
605 if (!sb->s_root)
606 return -ENOMEM;
607 return 0;
608}
609
610static int cramfs_blkdev_fill_super(struct super_block *sb, void *data,
611 int silent)
612{
613 struct cramfs_sb_info *sbi;
614 struct cramfs_super super;
615 int i, err;
616
617 sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
618 if (!sbi)
619 return -ENOMEM;
620 sb->s_fs_info = sbi;
621
622
623 for (i = 0; i < READ_BUFFERS; i++)
624 buffer_blocknr[i] = -1;
625
626 err = cramfs_read_super(sb, &super, silent);
627 if (err)
628 return err;
629 return cramfs_finalize_super(sb, &super.root);
630}
631
632static int cramfs_mtd_fill_super(struct super_block *sb, void *data,
633 int silent)
634{
635 struct cramfs_sb_info *sbi;
636 struct cramfs_super super;
637 int err;
638
639 sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
640 if (!sbi)
641 return -ENOMEM;
642 sb->s_fs_info = sbi;
643
644
645 err = mtd_point(sb->s_mtd, 0, PAGE_SIZE, &sbi->mtd_point_size,
646 &sbi->linear_virt_addr, &sbi->linear_phys_addr);
647 if (err || sbi->mtd_point_size != PAGE_SIZE) {
648 pr_err("unable to get direct memory access to mtd:%s\n",
649 sb->s_mtd->name);
650 return err ? : -ENODATA;
651 }
652
653 pr_info("checking physical address %pap for linear cramfs image\n",
654 &sbi->linear_phys_addr);
655 err = cramfs_read_super(sb, &super, silent);
656 if (err)
657 return err;
658
659
660 pr_info("linear cramfs image on mtd:%s appears to be %lu KB in size\n",
661 sb->s_mtd->name, sbi->size/1024);
662 mtd_unpoint(sb->s_mtd, 0, PAGE_SIZE);
663 err = mtd_point(sb->s_mtd, 0, sbi->size, &sbi->mtd_point_size,
664 &sbi->linear_virt_addr, &sbi->linear_phys_addr);
665 if (err || sbi->mtd_point_size != sbi->size) {
666 pr_err("unable to get direct memory access to mtd:%s\n",
667 sb->s_mtd->name);
668 return err ? : -ENODATA;
669 }
670
671 return cramfs_finalize_super(sb, &super.root);
672}
673
674static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf)
675{
676 struct super_block *sb = dentry->d_sb;
677 u64 id = 0;
678
679 if (sb->s_bdev)
680 id = huge_encode_dev(sb->s_bdev->bd_dev);
681 else if (sb->s_dev)
682 id = huge_encode_dev(sb->s_dev);
683
684 buf->f_type = CRAMFS_MAGIC;
685 buf->f_bsize = PAGE_SIZE;
686 buf->f_blocks = CRAMFS_SB(sb)->blocks;
687 buf->f_bfree = 0;
688 buf->f_bavail = 0;
689 buf->f_files = CRAMFS_SB(sb)->files;
690 buf->f_ffree = 0;
691 buf->f_fsid.val[0] = (u32)id;
692 buf->f_fsid.val[1] = (u32)(id >> 32);
693 buf->f_namelen = CRAMFS_MAXPATHLEN;
694 return 0;
695}
696
697
698
699
700static int cramfs_readdir(struct file *file, struct dir_context *ctx)
701{
702 struct inode *inode = file_inode(file);
703 struct super_block *sb = inode->i_sb;
704 char *buf;
705 unsigned int offset;
706
707
708 if (ctx->pos >= inode->i_size)
709 return 0;
710 offset = ctx->pos;
711
712 if (offset & 3)
713 return -EINVAL;
714
715 buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL);
716 if (!buf)
717 return -ENOMEM;
718
719 while (offset < inode->i_size) {
720 struct cramfs_inode *de;
721 unsigned long nextoffset;
722 char *name;
723 ino_t ino;
724 umode_t mode;
725 int namelen;
726
727 mutex_lock(&read_mutex);
728 de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN);
729 name = (char *)(de+1);
730
731
732
733
734
735
736 namelen = de->namelen << 2;
737 memcpy(buf, name, namelen);
738 ino = cramino(de, OFFSET(inode) + offset);
739 mode = de->mode;
740 mutex_unlock(&read_mutex);
741 nextoffset = offset + sizeof(*de) + namelen;
742 for (;;) {
743 if (!namelen) {
744 kfree(buf);
745 return -EIO;
746 }
747 if (buf[namelen-1])
748 break;
749 namelen--;
750 }
751 if (!dir_emit(ctx, buf, namelen, ino, mode >> 12))
752 break;
753
754 ctx->pos = offset = nextoffset;
755 }
756 kfree(buf);
757 return 0;
758}
759
760
761
762
763static struct dentry *cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
764{
765 unsigned int offset = 0;
766 struct inode *inode = NULL;
767 int sorted;
768
769 mutex_lock(&read_mutex);
770 sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS;
771 while (offset < dir->i_size) {
772 struct cramfs_inode *de;
773 char *name;
774 int namelen, retval;
775 int dir_off = OFFSET(dir) + offset;
776
777 de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN);
778 name = (char *)(de+1);
779
780
781 if (sorted && (dentry->d_name.name[0] < name[0]))
782 break;
783
784 namelen = de->namelen << 2;
785 offset += sizeof(*de) + namelen;
786
787
788 if (((dentry->d_name.len + 3) & ~3) != namelen)
789 continue;
790
791 for (;;) {
792 if (!namelen) {
793 inode = ERR_PTR(-EIO);
794 goto out;
795 }
796 if (name[namelen-1])
797 break;
798 namelen--;
799 }
800 if (namelen != dentry->d_name.len)
801 continue;
802 retval = memcmp(dentry->d_name.name, name, namelen);
803 if (retval > 0)
804 continue;
805 if (!retval) {
806 inode = get_cramfs_inode(dir->i_sb, de, dir_off);
807 break;
808 }
809
810 if (sorted)
811 break;
812 }
813out:
814 mutex_unlock(&read_mutex);
815 return d_splice_alias(inode, dentry);
816}
817
818static int cramfs_readpage(struct file *file, struct page *page)
819{
820 struct inode *inode = page->mapping->host;
821 u32 maxblock;
822 int bytes_filled;
823 void *pgdata;
824
825 maxblock = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
826 bytes_filled = 0;
827 pgdata = kmap(page);
828
829 if (page->index < maxblock) {
830 struct super_block *sb = inode->i_sb;
831 u32 blkptr_offset = OFFSET(inode) + page->index * 4;
832 u32 block_ptr, block_start, block_len;
833 bool uncompressed, direct;
834
835 mutex_lock(&read_mutex);
836 block_ptr = *(u32 *) cramfs_read(sb, blkptr_offset, 4);
837 uncompressed = (block_ptr & CRAMFS_BLK_FLAG_UNCOMPRESSED);
838 direct = (block_ptr & CRAMFS_BLK_FLAG_DIRECT_PTR);
839 block_ptr &= ~CRAMFS_BLK_FLAGS;
840
841 if (direct) {
842
843
844
845
846
847
848 block_start = block_ptr << CRAMFS_BLK_DIRECT_PTR_SHIFT;
849 if (uncompressed) {
850 block_len = PAGE_SIZE;
851
852 if (page->index == maxblock - 1)
853 block_len =
854 offset_in_page(inode->i_size);
855 } else {
856 block_len = *(u16 *)
857 cramfs_read(sb, block_start, 2);
858 block_start += 2;
859 }
860 } else {
861
862
863
864
865
866
867
868 block_start = OFFSET(inode) + maxblock * 4;
869 if (page->index)
870 block_start = *(u32 *)
871 cramfs_read(sb, blkptr_offset - 4, 4);
872
873 if (unlikely(block_start & CRAMFS_BLK_FLAG_DIRECT_PTR)) {
874
875 u32 prev_start = block_start;
876 block_start = prev_start & ~CRAMFS_BLK_FLAGS;
877 block_start <<= CRAMFS_BLK_DIRECT_PTR_SHIFT;
878 if (prev_start & CRAMFS_BLK_FLAG_UNCOMPRESSED) {
879 block_start += PAGE_SIZE;
880 } else {
881 block_len = *(u16 *)
882 cramfs_read(sb, block_start, 2);
883 block_start += 2 + block_len;
884 }
885 }
886 block_start &= ~CRAMFS_BLK_FLAGS;
887 block_len = block_ptr - block_start;
888 }
889
890 if (block_len == 0)
891 ;
892 else if (unlikely(block_len > 2*PAGE_SIZE ||
893 (uncompressed && block_len > PAGE_SIZE))) {
894 mutex_unlock(&read_mutex);
895 pr_err("bad data blocksize %u\n", block_len);
896 goto err;
897 } else if (uncompressed) {
898 memcpy(pgdata,
899 cramfs_read(sb, block_start, block_len),
900 block_len);
901 bytes_filled = block_len;
902 } else {
903 bytes_filled = cramfs_uncompress_block(pgdata,
904 PAGE_SIZE,
905 cramfs_read(sb, block_start, block_len),
906 block_len);
907 }
908 mutex_unlock(&read_mutex);
909 if (unlikely(bytes_filled < 0))
910 goto err;
911 }
912
913 memset(pgdata + bytes_filled, 0, PAGE_SIZE - bytes_filled);
914 flush_dcache_page(page);
915 kunmap(page);
916 SetPageUptodate(page);
917 unlock_page(page);
918 return 0;
919
920err:
921 kunmap(page);
922 ClearPageUptodate(page);
923 SetPageError(page);
924 unlock_page(page);
925 return 0;
926}
927
928static const struct address_space_operations cramfs_aops = {
929 .readpage = cramfs_readpage
930};
931
932
933
934
935
936
937
938
939static const struct file_operations cramfs_directory_operations = {
940 .llseek = generic_file_llseek,
941 .read = generic_read_dir,
942 .iterate_shared = cramfs_readdir,
943};
944
945static const struct inode_operations cramfs_dir_inode_operations = {
946 .lookup = cramfs_lookup,
947};
948
949static const struct super_operations cramfs_ops = {
950 .remount_fs = cramfs_remount,
951 .statfs = cramfs_statfs,
952};
953
954static struct dentry *cramfs_mount(struct file_system_type *fs_type, int flags,
955 const char *dev_name, void *data)
956{
957 struct dentry *ret = ERR_PTR(-ENOPROTOOPT);
958
959 if (IS_ENABLED(CONFIG_CRAMFS_MTD)) {
960 ret = mount_mtd(fs_type, flags, dev_name, data,
961 cramfs_mtd_fill_super);
962 if (!IS_ERR(ret))
963 return ret;
964 }
965 if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV)) {
966 ret = mount_bdev(fs_type, flags, dev_name, data,
967 cramfs_blkdev_fill_super);
968 }
969 return ret;
970}
971
972static struct file_system_type cramfs_fs_type = {
973 .owner = THIS_MODULE,
974 .name = "cramfs",
975 .mount = cramfs_mount,
976 .kill_sb = cramfs_kill_sb,
977 .fs_flags = FS_REQUIRES_DEV,
978};
979MODULE_ALIAS_FS("cramfs");
980
981static int __init init_cramfs_fs(void)
982{
983 int rv;
984
985 rv = cramfs_uncompress_init();
986 if (rv < 0)
987 return rv;
988 rv = register_filesystem(&cramfs_fs_type);
989 if (rv < 0)
990 cramfs_uncompress_exit();
991 return rv;
992}
993
994static void __exit exit_cramfs_fs(void)
995{
996 cramfs_uncompress_exit();
997 unregister_filesystem(&cramfs_fs_type);
998}
999
1000module_init(init_cramfs_fs)
1001module_exit(exit_cramfs_fs)
1002MODULE_LICENSE("GPL");
1003