1
2
3
4
5
6
7
8
9
10
11
12
13
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/fs_context.h>
28#include <linux/slab.h>
29#include <linux/vfs.h>
30#include <linux/mutex.h>
31#include <uapi/linux/cramfs_fs.h>
32#include <linux/uaccess.h>
33
34#include "internal.h"
35
36
37
38
39struct cramfs_sb_info {
40 unsigned long magic;
41 unsigned long size;
42 unsigned long blocks;
43 unsigned long files;
44 unsigned long flags;
45 void *linear_virt_addr;
46 resource_size_t linear_phys_addr;
47 size_t mtd_point_size;
48};
49
50static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
51{
52 return sb->s_fs_info;
53}
54
55static const struct super_operations cramfs_ops;
56static const struct inode_operations cramfs_dir_inode_operations;
57static const struct file_operations cramfs_directory_operations;
58static const struct file_operations cramfs_physmem_fops;
59static const struct address_space_operations cramfs_aops;
60
61static DEFINE_MUTEX(read_mutex);
62
63
64
65#define OFFSET(x) ((x)->i_ino)
66
67static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset)
68{
69 if (!cino->offset)
70 return offset + 1;
71 if (!cino->size)
72 return offset + 1;
73
74
75
76
77
78
79 switch (cino->mode & S_IFMT) {
80 case S_IFREG:
81 case S_IFDIR:
82 case S_IFLNK:
83 return cino->offset << 2;
84 default:
85 break;
86 }
87 return offset + 1;
88}
89
90static struct inode *get_cramfs_inode(struct super_block *sb,
91 const struct cramfs_inode *cramfs_inode, unsigned int offset)
92{
93 struct inode *inode;
94 static struct timespec64 zerotime;
95
96 inode = iget_locked(sb, cramino(cramfs_inode, offset));
97 if (!inode)
98 return ERR_PTR(-ENOMEM);
99 if (!(inode->i_state & I_NEW))
100 return inode;
101
102 switch (cramfs_inode->mode & S_IFMT) {
103 case S_IFREG:
104 inode->i_fop = &generic_ro_fops;
105 inode->i_data.a_ops = &cramfs_aops;
106 if (IS_ENABLED(CONFIG_CRAMFS_MTD) &&
107 CRAMFS_SB(sb)->flags & CRAMFS_FLAG_EXT_BLOCK_POINTERS &&
108 CRAMFS_SB(sb)->linear_phys_addr)
109 inode->i_fop = &cramfs_physmem_fops;
110 break;
111 case S_IFDIR:
112 inode->i_op = &cramfs_dir_inode_operations;
113 inode->i_fop = &cramfs_directory_operations;
114 break;
115 case S_IFLNK:
116 inode->i_op = &page_symlink_inode_operations;
117 inode_nohighmem(inode);
118 inode->i_data.a_ops = &cramfs_aops;
119 break;
120 default:
121 init_special_inode(inode, cramfs_inode->mode,
122 old_decode_dev(cramfs_inode->size));
123 }
124
125 inode->i_mode = cramfs_inode->mode;
126 i_uid_write(inode, cramfs_inode->uid);
127 i_gid_write(inode, cramfs_inode->gid);
128
129
130 if (!(inode->i_ino & 3)) {
131 inode->i_size = cramfs_inode->size;
132 inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
133 }
134
135
136 inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
137
138
139
140
141
142 unlock_new_inode(inode);
143
144 return inode;
145}
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161#define READ_BUFFERS (2)
162
163#define NEXT_BUFFER(_ix) ((_ix) ^ 1)
164
165
166
167
168
169
170#define BLKS_PER_BUF_SHIFT (2)
171#define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT)
172#define BUFFER_SIZE (BLKS_PER_BUF*PAGE_SIZE)
173
174static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE];
175static unsigned buffer_blocknr[READ_BUFFERS];
176static struct super_block *buffer_dev[READ_BUFFERS];
177static int next_buffer;
178
179
180
181
182static void *cramfs_blkdev_read(struct super_block *sb, unsigned int offset,
183 unsigned int len)
184{
185 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
186 struct page *pages[BLKS_PER_BUF];
187 unsigned i, blocknr, buffer;
188 unsigned long devsize;
189 char *data;
190
191 if (!len)
192 return NULL;
193 blocknr = offset >> PAGE_SHIFT;
194 offset &= PAGE_SIZE - 1;
195
196
197 for (i = 0; i < READ_BUFFERS; i++) {
198 unsigned int blk_offset;
199
200 if (buffer_dev[i] != sb)
201 continue;
202 if (blocknr < buffer_blocknr[i])
203 continue;
204 blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_SHIFT;
205 blk_offset += offset;
206 if (blk_offset > BUFFER_SIZE ||
207 blk_offset + len > BUFFER_SIZE)
208 continue;
209 return read_buffers[i] + blk_offset;
210 }
211
212 devsize = mapping->host->i_size >> PAGE_SHIFT;
213
214
215 for (i = 0; i < BLKS_PER_BUF; i++) {
216 struct page *page = NULL;
217
218 if (blocknr + i < devsize) {
219 page = read_mapping_page(mapping, blocknr + i, NULL);
220
221 if (IS_ERR(page))
222 page = NULL;
223 }
224 pages[i] = page;
225 }
226
227 for (i = 0; i < BLKS_PER_BUF; i++) {
228 struct page *page = pages[i];
229
230 if (page) {
231 wait_on_page_locked(page);
232 if (!PageUptodate(page)) {
233
234 put_page(page);
235 pages[i] = NULL;
236 }
237 }
238 }
239
240 buffer = next_buffer;
241 next_buffer = NEXT_BUFFER(buffer);
242 buffer_blocknr[buffer] = blocknr;
243 buffer_dev[buffer] = sb;
244
245 data = read_buffers[buffer];
246 for (i = 0; i < BLKS_PER_BUF; i++) {
247 struct page *page = pages[i];
248
249 if (page) {
250 memcpy(data, kmap(page), PAGE_SIZE);
251 kunmap(page);
252 put_page(page);
253 } else
254 memset(data, 0, PAGE_SIZE);
255 data += PAGE_SIZE;
256 }
257 return read_buffers[buffer] + offset;
258}
259
260
261
262
263static void *cramfs_direct_read(struct super_block *sb, unsigned int offset,
264 unsigned int len)
265{
266 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
267
268 if (!len)
269 return NULL;
270 if (len > sbi->size || offset > sbi->size - len)
271 return page_address(ZERO_PAGE(0));
272 return sbi->linear_virt_addr + offset;
273}
274
275
276
277
278
279static void *cramfs_read(struct super_block *sb, unsigned int offset,
280 unsigned int len)
281{
282 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
283
284 if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sbi->linear_virt_addr)
285 return cramfs_direct_read(sb, offset, len);
286 else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
287 return cramfs_blkdev_read(sb, offset, len);
288 else
289 return NULL;
290}
291
292
293
294
295
296
297static u32 cramfs_get_block_range(struct inode *inode, u32 pgoff, u32 *pages)
298{
299 struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
300 int i;
301 u32 *blockptrs, first_block_addr;
302
303
304
305
306
307
308 blockptrs = (u32 *)(sbi->linear_virt_addr + OFFSET(inode) + pgoff * 4);
309 first_block_addr = blockptrs[0] & ~CRAMFS_BLK_FLAGS;
310 i = 0;
311 do {
312 u32 block_off = i * (PAGE_SIZE >> CRAMFS_BLK_DIRECT_PTR_SHIFT);
313 u32 expect = (first_block_addr + block_off) |
314 CRAMFS_BLK_FLAG_DIRECT_PTR |
315 CRAMFS_BLK_FLAG_UNCOMPRESSED;
316 if (blockptrs[i] != expect) {
317 pr_debug("range: block %d/%d got %#x expects %#x\n",
318 pgoff+i, pgoff + *pages - 1,
319 blockptrs[i], expect);
320 if (i == 0)
321 return 0;
322 break;
323 }
324 } while (++i < *pages);
325
326 *pages = i;
327 return first_block_addr << CRAMFS_BLK_DIRECT_PTR_SHIFT;
328}
329
330#ifdef CONFIG_MMU
331
332
333
334
335
336
337
338static bool cramfs_last_page_is_shared(struct inode *inode)
339{
340 struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
341 u32 partial, last_page, blockaddr, *blockptrs;
342 char *tail_data;
343
344 partial = offset_in_page(inode->i_size);
345 if (!partial)
346 return false;
347 last_page = inode->i_size >> PAGE_SHIFT;
348 blockptrs = (u32 *)(sbi->linear_virt_addr + OFFSET(inode));
349 blockaddr = blockptrs[last_page] & ~CRAMFS_BLK_FLAGS;
350 blockaddr <<= CRAMFS_BLK_DIRECT_PTR_SHIFT;
351 tail_data = sbi->linear_virt_addr + blockaddr + partial;
352 return memchr_inv(tail_data, 0, PAGE_SIZE - partial) ? true : false;
353}
354
355static int cramfs_physmem_mmap(struct file *file, struct vm_area_struct *vma)
356{
357 struct inode *inode = file_inode(file);
358 struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
359 unsigned int pages, max_pages, offset;
360 unsigned long address, pgoff = vma->vm_pgoff;
361 char *bailout_reason;
362 int ret;
363
364 ret = generic_file_readonly_mmap(file, vma);
365 if (ret)
366 return ret;
367
368
369
370
371
372
373
374 bailout_reason = "vma is writable";
375 if (vma->vm_flags & VM_WRITE)
376 goto bailout;
377
378 max_pages = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
379 bailout_reason = "beyond file limit";
380 if (pgoff >= max_pages)
381 goto bailout;
382 pages = min(vma_pages(vma), max_pages - pgoff);
383
384 offset = cramfs_get_block_range(inode, pgoff, &pages);
385 bailout_reason = "unsuitable block layout";
386 if (!offset)
387 goto bailout;
388 address = sbi->linear_phys_addr + offset;
389 bailout_reason = "data is not page aligned";
390 if (!PAGE_ALIGNED(address))
391 goto bailout;
392
393
394 if (pgoff + pages == max_pages && cramfs_last_page_is_shared(inode)) {
395 pr_debug("mmap: %pD: last page is shared\n", file);
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 %pD[%lu] at 0x%08lx (%u/%lu pages) "
433 "to vma 0x%08lx, page_prot 0x%llx\n", file,
434 pgoff, address, pages, vma_pages(vma), vma->vm_start,
435 (unsigned long long)pgprot_val(vma->vm_page_prot));
436 return ret;
437
438bailout:
439 pr_debug("%pD[%lu]: direct mmap impossible: %s\n",
440 file, pgoff, bailout_reason);
441
442 return 0;
443}
444
445#else
446
447static int cramfs_physmem_mmap(struct file *file, struct vm_area_struct *vma)
448{
449 return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS;
450}
451
452static unsigned long cramfs_physmem_get_unmapped_area(struct file *file,
453 unsigned long addr, unsigned long len,
454 unsigned long pgoff, unsigned long flags)
455{
456 struct inode *inode = file_inode(file);
457 struct super_block *sb = inode->i_sb;
458 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
459 unsigned int pages, block_pages, max_pages, offset;
460
461 pages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
462 max_pages = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
463 if (pgoff >= max_pages || pages > max_pages - pgoff)
464 return -EINVAL;
465 block_pages = pages;
466 offset = cramfs_get_block_range(inode, pgoff, &block_pages);
467 if (!offset || block_pages != pages)
468 return -ENOSYS;
469 addr = sbi->linear_phys_addr + offset;
470 pr_debug("get_unmapped for %pD ofs %#lx siz %lu at 0x%08lx\n",
471 file, pgoff*PAGE_SIZE, len, addr);
472 return addr;
473}
474
475static unsigned int cramfs_physmem_mmap_capabilities(struct file *file)
476{
477 return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT |
478 NOMMU_MAP_READ | NOMMU_MAP_EXEC;
479}
480
481#endif
482
483static const struct file_operations cramfs_physmem_fops = {
484 .llseek = generic_file_llseek,
485 .read_iter = generic_file_read_iter,
486 .splice_read = generic_file_splice_read,
487 .mmap = cramfs_physmem_mmap,
488#ifndef CONFIG_MMU
489 .get_unmapped_area = cramfs_physmem_get_unmapped_area,
490 .mmap_capabilities = cramfs_physmem_mmap_capabilities,
491#endif
492};
493
494static void cramfs_kill_sb(struct super_block *sb)
495{
496 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
497
498 if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sb->s_mtd) {
499 if (sbi && sbi->mtd_point_size)
500 mtd_unpoint(sb->s_mtd, 0, sbi->mtd_point_size);
501 kill_mtd_super(sb);
502 } else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV) && sb->s_bdev) {
503 kill_block_super(sb);
504 }
505 kfree(sbi);
506}
507
508static int cramfs_reconfigure(struct fs_context *fc)
509{
510 sync_filesystem(fc->root->d_sb);
511 fc->sb_flags |= SB_RDONLY;
512 return 0;
513}
514
515static int cramfs_read_super(struct super_block *sb, struct fs_context *fc,
516 struct cramfs_super *super)
517{
518 struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
519 unsigned long root_offset;
520 bool silent = fc->sb_flags & SB_SILENT;
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 errorfc(fc, "wrong endianness");
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 errorfc(fc, "wrong endianness");
548 else if (!silent)
549 errorfc(fc, "wrong magic");
550 return -EINVAL;
551 }
552 }
553
554
555 if (super->flags & ~CRAMFS_SUPPORTED_FLAGS) {
556 errorfc(fc, "unsupported filesystem features");
557 return -EINVAL;
558 }
559
560
561 if (!S_ISDIR(super->root.mode)) {
562 errorfc(fc, "root is not a directory");
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 infofc(fc, "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 errorfc(fc, "bad root offset %lu", 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_time_min = 0;
601 sb->s_time_max = 0;
602 sb->s_op = &cramfs_ops;
603 root = get_cramfs_inode(sb, cramfs_root, 0);
604 if (IS_ERR(root))
605 return PTR_ERR(root);
606 sb->s_root = d_make_root(root);
607 if (!sb->s_root)
608 return -ENOMEM;
609 return 0;
610}
611
612static int cramfs_blkdev_fill_super(struct super_block *sb, struct fs_context *fc)
613{
614 struct cramfs_sb_info *sbi;
615 struct cramfs_super super;
616 int i, err;
617
618 sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
619 if (!sbi)
620 return -ENOMEM;
621 sb->s_fs_info = sbi;
622
623
624 for (i = 0; i < READ_BUFFERS; i++)
625 buffer_blocknr[i] = -1;
626
627 err = cramfs_read_super(sb, fc, &super);
628 if (err)
629 return err;
630 return cramfs_finalize_super(sb, &super.root);
631}
632
633static int cramfs_mtd_fill_super(struct super_block *sb, struct fs_context *fc)
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, fc, &super);
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 = u64_to_fsid(id);
692 buf->f_namelen = CRAMFS_MAXPATHLEN;
693 return 0;
694}
695
696
697
698
699static int cramfs_readdir(struct file *file, struct dir_context *ctx)
700{
701 struct inode *inode = file_inode(file);
702 struct super_block *sb = inode->i_sb;
703 char *buf;
704 unsigned int offset;
705
706
707 if (ctx->pos >= inode->i_size)
708 return 0;
709 offset = ctx->pos;
710
711 if (offset & 3)
712 return -EINVAL;
713
714 buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL);
715 if (!buf)
716 return -ENOMEM;
717
718 while (offset < inode->i_size) {
719 struct cramfs_inode *de;
720 unsigned long nextoffset;
721 char *name;
722 ino_t ino;
723 umode_t mode;
724 int namelen;
725
726 mutex_lock(&read_mutex);
727 de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN);
728 name = (char *)(de+1);
729
730
731
732
733
734
735 namelen = de->namelen << 2;
736 memcpy(buf, name, namelen);
737 ino = cramino(de, OFFSET(inode) + offset);
738 mode = de->mode;
739 mutex_unlock(&read_mutex);
740 nextoffset = offset + sizeof(*de) + namelen;
741 for (;;) {
742 if (!namelen) {
743 kfree(buf);
744 return -EIO;
745 }
746 if (buf[namelen-1])
747 break;
748 namelen--;
749 }
750 if (!dir_emit(ctx, buf, namelen, ino, mode >> 12))
751 break;
752
753 ctx->pos = offset = nextoffset;
754 }
755 kfree(buf);
756 return 0;
757}
758
759
760
761
762static struct dentry *cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
763{
764 unsigned int offset = 0;
765 struct inode *inode = NULL;
766 int sorted;
767
768 mutex_lock(&read_mutex);
769 sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS;
770 while (offset < dir->i_size) {
771 struct cramfs_inode *de;
772 char *name;
773 int namelen, retval;
774 int dir_off = OFFSET(dir) + offset;
775
776 de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN);
777 name = (char *)(de+1);
778
779
780 if (sorted && (dentry->d_name.name[0] < name[0]))
781 break;
782
783 namelen = de->namelen << 2;
784 offset += sizeof(*de) + namelen;
785
786
787 if (((dentry->d_name.len + 3) & ~3) != namelen)
788 continue;
789
790 for (;;) {
791 if (!namelen) {
792 inode = ERR_PTR(-EIO);
793 goto out;
794 }
795 if (name[namelen-1])
796 break;
797 namelen--;
798 }
799 if (namelen != dentry->d_name.len)
800 continue;
801 retval = memcmp(dentry->d_name.name, name, namelen);
802 if (retval > 0)
803 continue;
804 if (!retval) {
805 inode = get_cramfs_inode(dir->i_sb, de, dir_off);
806 break;
807 }
808
809 if (sorted)
810 break;
811 }
812out:
813 mutex_unlock(&read_mutex);
814 return d_splice_alias(inode, dentry);
815}
816
817static int cramfs_readpage(struct file *file, struct page *page)
818{
819 struct inode *inode = page->mapping->host;
820 u32 maxblock;
821 int bytes_filled;
822 void *pgdata;
823
824 maxblock = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
825 bytes_filled = 0;
826 pgdata = kmap(page);
827
828 if (page->index < maxblock) {
829 struct super_block *sb = inode->i_sb;
830 u32 blkptr_offset = OFFSET(inode) + page->index * 4;
831 u32 block_ptr, block_start, block_len;
832 bool uncompressed, direct;
833
834 mutex_lock(&read_mutex);
835 block_ptr = *(u32 *) cramfs_read(sb, blkptr_offset, 4);
836 uncompressed = (block_ptr & CRAMFS_BLK_FLAG_UNCOMPRESSED);
837 direct = (block_ptr & CRAMFS_BLK_FLAG_DIRECT_PTR);
838 block_ptr &= ~CRAMFS_BLK_FLAGS;
839
840 if (direct) {
841
842
843
844
845
846
847 block_start = block_ptr << CRAMFS_BLK_DIRECT_PTR_SHIFT;
848 if (uncompressed) {
849 block_len = PAGE_SIZE;
850
851 if (page->index == maxblock - 1)
852 block_len =
853 offset_in_page(inode->i_size);
854 } else {
855 block_len = *(u16 *)
856 cramfs_read(sb, block_start, 2);
857 block_start += 2;
858 }
859 } else {
860
861
862
863
864
865
866
867 block_start = OFFSET(inode) + maxblock * 4;
868 if (page->index)
869 block_start = *(u32 *)
870 cramfs_read(sb, blkptr_offset - 4, 4);
871
872 if (unlikely(block_start & CRAMFS_BLK_FLAG_DIRECT_PTR)) {
873
874 u32 prev_start = block_start;
875 block_start = prev_start & ~CRAMFS_BLK_FLAGS;
876 block_start <<= CRAMFS_BLK_DIRECT_PTR_SHIFT;
877 if (prev_start & CRAMFS_BLK_FLAG_UNCOMPRESSED) {
878 block_start += PAGE_SIZE;
879 } else {
880 block_len = *(u16 *)
881 cramfs_read(sb, block_start, 2);
882 block_start += 2 + block_len;
883 }
884 }
885 block_start &= ~CRAMFS_BLK_FLAGS;
886 block_len = block_ptr - block_start;
887 }
888
889 if (block_len == 0)
890 ;
891 else if (unlikely(block_len > 2*PAGE_SIZE ||
892 (uncompressed && block_len > PAGE_SIZE))) {
893 mutex_unlock(&read_mutex);
894 pr_err("bad data blocksize %u\n", block_len);
895 goto err;
896 } else if (uncompressed) {
897 memcpy(pgdata,
898 cramfs_read(sb, block_start, block_len),
899 block_len);
900 bytes_filled = block_len;
901 } else {
902 bytes_filled = cramfs_uncompress_block(pgdata,
903 PAGE_SIZE,
904 cramfs_read(sb, block_start, block_len),
905 block_len);
906 }
907 mutex_unlock(&read_mutex);
908 if (unlikely(bytes_filled < 0))
909 goto err;
910 }
911
912 memset(pgdata + bytes_filled, 0, PAGE_SIZE - bytes_filled);
913 flush_dcache_page(page);
914 kunmap(page);
915 SetPageUptodate(page);
916 unlock_page(page);
917 return 0;
918
919err:
920 kunmap(page);
921 ClearPageUptodate(page);
922 SetPageError(page);
923 unlock_page(page);
924 return 0;
925}
926
927static const struct address_space_operations cramfs_aops = {
928 .readpage = cramfs_readpage
929};
930
931
932
933
934
935
936
937
938static const struct file_operations cramfs_directory_operations = {
939 .llseek = generic_file_llseek,
940 .read = generic_read_dir,
941 .iterate_shared = cramfs_readdir,
942};
943
944static const struct inode_operations cramfs_dir_inode_operations = {
945 .lookup = cramfs_lookup,
946};
947
948static const struct super_operations cramfs_ops = {
949 .statfs = cramfs_statfs,
950};
951
952static int cramfs_get_tree(struct fs_context *fc)
953{
954 int ret = -ENOPROTOOPT;
955
956 if (IS_ENABLED(CONFIG_CRAMFS_MTD)) {
957 ret = get_tree_mtd(fc, cramfs_mtd_fill_super);
958 if (!ret)
959 return 0;
960 }
961 if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
962 ret = get_tree_bdev(fc, cramfs_blkdev_fill_super);
963 return ret;
964}
965
966static const struct fs_context_operations cramfs_context_ops = {
967 .get_tree = cramfs_get_tree,
968 .reconfigure = cramfs_reconfigure,
969};
970
971
972
973
974static int cramfs_init_fs_context(struct fs_context *fc)
975{
976 fc->ops = &cramfs_context_ops;
977 return 0;
978}
979
980static struct file_system_type cramfs_fs_type = {
981 .owner = THIS_MODULE,
982 .name = "cramfs",
983 .init_fs_context = cramfs_init_fs_context,
984 .kill_sb = cramfs_kill_sb,
985 .fs_flags = FS_REQUIRES_DEV,
986};
987MODULE_ALIAS_FS("cramfs");
988
989static int __init init_cramfs_fs(void)
990{
991 int rv;
992
993 rv = cramfs_uncompress_init();
994 if (rv < 0)
995 return rv;
996 rv = register_filesystem(&cramfs_fs_type);
997 if (rv < 0)
998 cramfs_uncompress_exit();
999 return rv;
1000}
1001
1002static void __exit exit_cramfs_fs(void)
1003{
1004 cramfs_uncompress_exit();
1005 unregister_filesystem(&cramfs_fs_type);
1006}
1007
1008module_init(init_cramfs_fs)
1009module_exit(exit_cramfs_fs)
1010MODULE_LICENSE("GPL");
1011