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Avoid beyond bounds copy while caching ACL
[zen-stable.git] / fs / hugetlbfs / inode.c
blobc60267e30839003321a6efa4c46fee80406fddda
1 /*
2 * hugetlbpage-backed filesystem. Based on ramfs.
3 *
4 * William Irwin, 2002
5 *
6 * Copyright (C) 2002 Linus Torvalds.
7 */
8
9 #include <linux/module.h>
10 #include <linux/thread_info.h>
11 #include <asm/current.h>
12 #include <linux/sched.h> /* remove ASAP */
13 #include <linux/fs.h>
14 #include <linux/mount.h>
15 #include <linux/file.h>
16 #include <linux/kernel.h>
17 #include <linux/writeback.h>
18 #include <linux/pagemap.h>
19 #include <linux/highmem.h>
20 #include <linux/init.h>
21 #include <linux/string.h>
22 #include <linux/capability.h>
23 #include <linux/ctype.h>
24 #include <linux/backing-dev.h>
25 #include <linux/hugetlb.h>
26 #include <linux/pagevec.h>
27 #include <linux/parser.h>
28 #include <linux/mman.h>
29 #include <linux/slab.h>
30 #include <linux/dnotify.h>
31 #include <linux/statfs.h>
32 #include <linux/security.h>
33 #include <linux/magic.h>
34 #include <linux/migrate.h>
35
36 #include <asm/uaccess.h>
37
38 static const struct super_operations hugetlbfs_ops;
39 static const struct address_space_operations hugetlbfs_aops;
40 const struct file_operations hugetlbfs_file_operations;
41 static const struct inode_operations hugetlbfs_dir_inode_operations;
42 static const struct inode_operations hugetlbfs_inode_operations;
43
44 static struct backing_dev_info hugetlbfs_backing_dev_info = {
45 .name = "hugetlbfs",
46 .ra_pages = 0, /* No readahead */
47 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
48 };
49
50 int sysctl_hugetlb_shm_group;
51
52 enum {
53 Opt_size, Opt_nr_inodes,
54 Opt_mode, Opt_uid, Opt_gid,
55 Opt_pagesize,
56 Opt_err,
57 };
58
59 static const match_table_t tokens = {
60 {Opt_size, "size=%s"},
61 {Opt_nr_inodes, "nr_inodes=%s"},
62 {Opt_mode, "mode=%o"},
63 {Opt_uid, "uid=%u"},
64 {Opt_gid, "gid=%u"},
65 {Opt_pagesize, "pagesize=%s"},
66 {Opt_err, NULL},
67 };
68
69 static void huge_pagevec_release(struct pagevec *pvec)
70 {
71 int i;
72
73 for (i = 0; i < pagevec_count(pvec); ++i)
74 put_page(pvec->pages[i]);
75
76 pagevec_reinit(pvec);
77 }
78
79 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
80 {
81 struct inode *inode = file->f_path.dentry->d_inode;
82 loff_t len, vma_len;
83 int ret;
84 struct hstate *h = hstate_file(file);
85
86 /*
87 * vma address alignment (but not the pgoff alignment) has
88 * already been checked by prepare_hugepage_range. If you add
89 * any error returns here, do so after setting VM_HUGETLB, so
90 * is_vm_hugetlb_page tests below unmap_region go the right
91 * way when do_mmap_pgoff unwinds (may be important on powerpc
92 * and ia64).
93 */
94 vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
95 vma->vm_ops = &hugetlb_vm_ops;
96
97 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
98 return -EINVAL;
99
100 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
101
102 mutex_lock(&inode->i_mutex);
103 file_accessed(file);
104
105 ret = -ENOMEM;
106 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
107
108 if (hugetlb_reserve_pages(inode,
109 vma->vm_pgoff >> huge_page_order(h),
110 len >> huge_page_shift(h), vma,
111 vma->vm_flags))
112 goto out;
113
114 ret = 0;
115 hugetlb_prefault_arch_hook(vma->vm_mm);
116 if (vma->vm_flags & VM_WRITE && inode->i_size < len)
117 inode->i_size = len;
118 out:
119 mutex_unlock(&inode->i_mutex);
120
121 return ret;
122 }
123
124 /*
125 * Called under down_write(mmap_sem).
126 */
127
128 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
129 static unsigned long
130 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
131 unsigned long len, unsigned long pgoff, unsigned long flags)
132 {
133 struct mm_struct *mm = current->mm;
134 struct vm_area_struct *vma;
135 unsigned long start_addr;
136 struct hstate *h = hstate_file(file);
137
138 if (len & ~huge_page_mask(h))
139 return -EINVAL;
140 if (len > TASK_SIZE)
141 return -ENOMEM;
142
143 if (flags & MAP_FIXED) {
144 if (prepare_hugepage_range(file, addr, len))
145 return -EINVAL;
146 return addr;
147 }
148
149 if (addr) {
150 addr = ALIGN(addr, huge_page_size(h));
151 vma = find_vma(mm, addr);
152 if (TASK_SIZE - len >= addr &&
153 (!vma || addr + len <= vma->vm_start))
154 return addr;
155 }
156
157 start_addr = mm->free_area_cache;
158
159 if (len <= mm->cached_hole_size)
160 start_addr = TASK_UNMAPPED_BASE;
161
162 full_search:
163 addr = ALIGN(start_addr, huge_page_size(h));
164
165 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
166 /* At this point: (!vma || addr < vma->vm_end). */
167 if (TASK_SIZE - len < addr) {
168 /*
169 * Start a new search - just in case we missed
170 * some holes.
171 */
172 if (start_addr != TASK_UNMAPPED_BASE) {
173 start_addr = TASK_UNMAPPED_BASE;
174 goto full_search;
175 }
176 return -ENOMEM;
177 }
178
179 if (!vma || addr + len <= vma->vm_start)
180 return addr;
181 addr = ALIGN(vma->vm_end, huge_page_size(h));
182 }
183 }
184 #endif
185
186 static int
187 hugetlbfs_read_actor(struct page *page, unsigned long offset,
188 char __user *buf, unsigned long count,
189 unsigned long size)
190 {
191 char *kaddr;
192 unsigned long left, copied = 0;
193 int i, chunksize;
194
195 if (size > count)
196 size = count;
197
198 /* Find which 4k chunk and offset with in that chunk */
199 i = offset >> PAGE_CACHE_SHIFT;
200 offset = offset & ~PAGE_CACHE_MASK;
201
202 while (size) {
203 chunksize = PAGE_CACHE_SIZE;
204 if (offset)
205 chunksize -= offset;
206 if (chunksize > size)
207 chunksize = size;
208 kaddr = kmap(&page[i]);
209 left = __copy_to_user(buf, kaddr + offset, chunksize);
210 kunmap(&page[i]);
211 if (left) {
212 copied += (chunksize - left);
213 break;
214 }
215 offset = 0;
216 size -= chunksize;
217 buf += chunksize;
218 copied += chunksize;
219 i++;
220 }
221 return copied ? copied : -EFAULT;
222 }
223
224 /*
225 * Support for read() - Find the page attached to f_mapping and copy out the
226 * data. Its *very* similar to do_generic_mapping_read(), we can't use that
227 * since it has PAGE_CACHE_SIZE assumptions.
228 */
229 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
230 size_t len, loff_t *ppos)
231 {
232 struct hstate *h = hstate_file(filp);
233 struct address_space *mapping = filp->f_mapping;
234 struct inode *inode = mapping->host;
235 unsigned long index = *ppos >> huge_page_shift(h);
236 unsigned long offset = *ppos & ~huge_page_mask(h);
237 unsigned long end_index;
238 loff_t isize;
239 ssize_t retval = 0;
240
241 /* validate length */
242 if (len == 0)
243 goto out;
244
245 for (;;) {
246 struct page *page;
247 unsigned long nr, ret;
248 int ra;
249
250 /* nr is the maximum number of bytes to copy from this page */
251 nr = huge_page_size(h);
252 isize = i_size_read(inode);
253 if (!isize)
254 goto out;
255 end_index = (isize - 1) >> huge_page_shift(h);
256 if (index >= end_index) {
257 if (index > end_index)
258 goto out;
259 nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
260 if (nr <= offset)
261 goto out;
262 }
263 nr = nr - offset;
264
265 /* Find the page */
266 page = find_lock_page(mapping, index);
267 if (unlikely(page == NULL)) {
268 /*
269 * We have a HOLE, zero out the user-buffer for the
270 * length of the hole or request.
271 */
272 ret = len < nr ? len : nr;
273 if (clear_user(buf, ret))
274 ra = -EFAULT;
275 else
276 ra = 0;
277 } else {
278 unlock_page(page);
279
280 /*
281 * We have the page, copy it to user space buffer.
282 */
283 ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
284 ret = ra;
285 page_cache_release(page);
286 }
287 if (ra < 0) {
288 if (retval == 0)
289 retval = ra;
290 goto out;
291 }
292
293 offset += ret;
294 retval += ret;
295 len -= ret;
296 index += offset >> huge_page_shift(h);
297 offset &= ~huge_page_mask(h);
298
299 /* short read or no more work */
300 if ((ret != nr) || (len == 0))
301 break;
302 }
303 out:
304 *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
305 return retval;
306 }
307
308 static int hugetlbfs_write_begin(struct file *file,
309 struct address_space *mapping,
310 loff_t pos, unsigned len, unsigned flags,
311 struct page **pagep, void **fsdata)
312 {
313 return -EINVAL;
314 }
315
316 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
317 loff_t pos, unsigned len, unsigned copied,
318 struct page *page, void *fsdata)
319 {
320 BUG();
321 return -EINVAL;
322 }
323
324 static void truncate_huge_page(struct page *page)
325 {
326 cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
327 ClearPageUptodate(page);
328 delete_from_page_cache(page);
329 }
330
331 static void truncate_hugepages(struct inode *inode, loff_t lstart)
332 {
333 struct hstate *h = hstate_inode(inode);
334 struct address_space *mapping = &inode->i_data;
335 const pgoff_t start = lstart >> huge_page_shift(h);
336 struct pagevec pvec;
337 pgoff_t next;
338 int i, freed = 0;
339
340 pagevec_init(&pvec, 0);
341 next = start;
342 while (1) {
343 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
344 if (next == start)
345 break;
346 next = start;
347 continue;
348 }
349
350 for (i = 0; i < pagevec_count(&pvec); ++i) {
351 struct page *page = pvec.pages[i];
352
353 lock_page(page);
354 if (page->index > next)
355 next = page->index;
356 ++next;
357 truncate_huge_page(page);
358 unlock_page(page);
359 freed++;
360 }
361 huge_pagevec_release(&pvec);
362 }
363 BUG_ON(!lstart && mapping->nrpages);
364 hugetlb_unreserve_pages(inode, start, freed);
365 }
366
367 static void hugetlbfs_evict_inode(struct inode *inode)
368 {
369 truncate_hugepages(inode, 0);
370 end_writeback(inode);
371 }
372
373 static inline void
374 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
375 {
376 struct vm_area_struct *vma;
377 struct prio_tree_iter iter;
378
379 vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
380 unsigned long v_offset;
381
382 /*
383 * Can the expression below overflow on 32-bit arches?
384 * No, because the prio_tree returns us only those vmas
385 * which overlap the truncated area starting at pgoff,
386 * and no vma on a 32-bit arch can span beyond the 4GB.
387 */
388 if (vma->vm_pgoff < pgoff)
389 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
390 else
391 v_offset = 0;
392
393 __unmap_hugepage_range(vma,
394 vma->vm_start + v_offset, vma->vm_end, NULL);
395 }
396 }
397
398 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
399 {
400 pgoff_t pgoff;
401 struct address_space *mapping = inode->i_mapping;
402 struct hstate *h = hstate_inode(inode);
403
404 BUG_ON(offset & ~huge_page_mask(h));
405 pgoff = offset >> PAGE_SHIFT;
406
407 i_size_write(inode, offset);
408 mutex_lock(&mapping->i_mmap_mutex);
409 if (!prio_tree_empty(&mapping->i_mmap))
410 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
411 mutex_unlock(&mapping->i_mmap_mutex);
412 truncate_hugepages(inode, offset);
413 return 0;
414 }
415
416 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
417 {
418 struct inode *inode = dentry->d_inode;
419 struct hstate *h = hstate_inode(inode);
420 int error;
421 unsigned int ia_valid = attr->ia_valid;
422
423 BUG_ON(!inode);
424
425 error = inode_change_ok(inode, attr);
426 if (error)
427 return error;
428
429 if (ia_valid & ATTR_SIZE) {
430 error = -EINVAL;
431 if (attr->ia_size & ~huge_page_mask(h))
432 return -EINVAL;
433 error = hugetlb_vmtruncate(inode, attr->ia_size);
434 if (error)
435 return error;
436 }
437
438 setattr_copy(inode, attr);
439 mark_inode_dirty(inode);
440 return 0;
441 }
442
443 static struct inode *hugetlbfs_get_root(struct super_block *sb,
444 struct hugetlbfs_config *config)
445 {
446 struct inode *inode;
447
448 inode = new_inode(sb);
449 if (inode) {
450 struct hugetlbfs_inode_info *info;
451 inode->i_ino = get_next_ino();
452 inode->i_mode = S_IFDIR | config->mode;
453 inode->i_uid = config->uid;
454 inode->i_gid = config->gid;
455 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
456 info = HUGETLBFS_I(inode);
457 mpol_shared_policy_init(&info->policy, NULL);
458 inode->i_op = &hugetlbfs_dir_inode_operations;
459 inode->i_fop = &simple_dir_operations;
460 /* directory inodes start off with i_nlink == 2 (for "." entry) */
461 inc_nlink(inode);
462 }
463 return inode;
464 }
465
466 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
467 struct inode *dir,
468 umode_t mode, dev_t dev)
469 {
470 struct inode *inode;
471
472 inode = new_inode(sb);
473 if (inode) {
474 struct hugetlbfs_inode_info *info;
475 inode->i_ino = get_next_ino();
476 inode_init_owner(inode, dir, mode);
477 inode->i_mapping->a_ops = &hugetlbfs_aops;
478 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
479 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
480 INIT_LIST_HEAD(&inode->i_mapping->private_list);
481 info = HUGETLBFS_I(inode);
482 /*
483 * The policy is initialized here even if we are creating a
484 * private inode because initialization simply creates an
485 * an empty rb tree and calls spin_lock_init(), later when we
486 * call mpol_free_shared_policy() it will just return because
487 * the rb tree will still be empty.
488 */
489 mpol_shared_policy_init(&info->policy, NULL);
490 switch (mode & S_IFMT) {
491 default:
492 init_special_inode(inode, mode, dev);
493 break;
494 case S_IFREG:
495 inode->i_op = &hugetlbfs_inode_operations;
496 inode->i_fop = &hugetlbfs_file_operations;
497 break;
498 case S_IFDIR:
499 inode->i_op = &hugetlbfs_dir_inode_operations;
500 inode->i_fop = &simple_dir_operations;
501
502 /* directory inodes start off with i_nlink == 2 (for "." entry) */
503 inc_nlink(inode);
504 break;
505 case S_IFLNK:
506 inode->i_op = &page_symlink_inode_operations;
507 break;
508 }
509 lockdep_annotate_inode_mutex_key(inode);
510 }
511 return inode;
512 }
513
514 /*
515 * File creation. Allocate an inode, and we're done..
516 */
517 static int hugetlbfs_mknod(struct inode *dir,
518 struct dentry *dentry, umode_t mode, dev_t dev)
519 {
520 struct inode *inode;
521 int error = -ENOSPC;
522
523 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
524 if (inode) {
525 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
526 d_instantiate(dentry, inode);
527 dget(dentry); /* Extra count - pin the dentry in core */
528 error = 0;
529 }
530 return error;
531 }
532
533 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
534 {
535 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
536 if (!retval)
537 inc_nlink(dir);
538 return retval;
539 }
540
541 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, struct nameidata *nd)
542 {
543 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
544 }
545
546 static int hugetlbfs_symlink(struct inode *dir,
547 struct dentry *dentry, const char *symname)
548 {
549 struct inode *inode;
550 int error = -ENOSPC;
551
552 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
553 if (inode) {
554 int l = strlen(symname)+1;
555 error = page_symlink(inode, symname, l);
556 if (!error) {
557 d_instantiate(dentry, inode);
558 dget(dentry);
559 } else
560 iput(inode);
561 }
562 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
563
564 return error;
565 }
566
567 /*
568 * mark the head page dirty
569 */
570 static int hugetlbfs_set_page_dirty(struct page *page)
571 {
572 struct page *head = compound_head(page);
573
574 SetPageDirty(head);
575 return 0;
576 }
577
578 static int hugetlbfs_migrate_page(struct address_space *mapping,
579 struct page *newpage, struct page *page,
580 enum migrate_mode mode)
581 {
582 int rc;
583
584 rc = migrate_huge_page_move_mapping(mapping, newpage, page);
585 if (rc)
586 return rc;
587 migrate_page_copy(newpage, page);
588
589 return 0;
590 }
591
592 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
593 {
594 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
595 struct hstate *h = hstate_inode(dentry->d_inode);
596
597 buf->f_type = HUGETLBFS_MAGIC;
598 buf->f_bsize = huge_page_size(h);
599 if (sbinfo) {
600 spin_lock(&sbinfo->stat_lock);
601 /* If no limits set, just report 0 for max/free/used
602 * blocks, like simple_statfs() */
603 if (sbinfo->spool) {
604 long free_pages;
605
606 spin_lock(&sbinfo->spool->lock);
607 buf->f_blocks = sbinfo->spool->max_hpages;
608 free_pages = sbinfo->spool->max_hpages
609 - sbinfo->spool->used_hpages;
610 buf->f_bavail = buf->f_bfree = free_pages;
611 spin_unlock(&sbinfo->spool->lock);
612 buf->f_files = sbinfo->max_inodes;
613 buf->f_ffree = sbinfo->free_inodes;
614 }
615 spin_unlock(&sbinfo->stat_lock);
616 }
617 buf->f_namelen = NAME_MAX;
618 return 0;
619 }
620
621 static void hugetlbfs_put_super(struct super_block *sb)
622 {
623 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
624
625 if (sbi) {
626 sb->s_fs_info = NULL;
627
628 if (sbi->spool)
629 hugepage_put_subpool(sbi->spool);
630
631 kfree(sbi);
632 }
633 }
634
635 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
636 {
637 if (sbinfo->free_inodes >= 0) {
638 spin_lock(&sbinfo->stat_lock);
639 if (unlikely(!sbinfo->free_inodes)) {
640 spin_unlock(&sbinfo->stat_lock);
641 return 0;
642 }
643 sbinfo->free_inodes--;
644 spin_unlock(&sbinfo->stat_lock);
645 }
646
647 return 1;
648 }
649
650 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
651 {
652 if (sbinfo->free_inodes >= 0) {
653 spin_lock(&sbinfo->stat_lock);
654 sbinfo->free_inodes++;
655 spin_unlock(&sbinfo->stat_lock);
656 }
657 }
658
659
660 static struct kmem_cache *hugetlbfs_inode_cachep;
661
662 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
663 {
664 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
665 struct hugetlbfs_inode_info *p;
666
667 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
668 return NULL;
669 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
670 if (unlikely(!p)) {
671 hugetlbfs_inc_free_inodes(sbinfo);
672 return NULL;
673 }
674 return &p->vfs_inode;
675 }
676
677 static void hugetlbfs_i_callback(struct rcu_head *head)
678 {
679 struct inode *inode = container_of(head, struct inode, i_rcu);
680 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
681 }
682
683 static void hugetlbfs_destroy_inode(struct inode *inode)
684 {
685 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
686 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
687 call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
688 }
689
690 static const struct address_space_operations hugetlbfs_aops = {
691 .write_begin = hugetlbfs_write_begin,
692 .write_end = hugetlbfs_write_end,
693 .set_page_dirty = hugetlbfs_set_page_dirty,
694 .migratepage = hugetlbfs_migrate_page,
695 };
696
697
698 static void init_once(void *foo)
699 {
700 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
701
702 inode_init_once(&ei->vfs_inode);
703 }
704
705 const struct file_operations hugetlbfs_file_operations = {
706 .read = hugetlbfs_read,
707 .mmap = hugetlbfs_file_mmap,
708 .fsync = noop_fsync,
709 .get_unmapped_area = hugetlb_get_unmapped_area,
710 .llseek = default_llseek,
711 };
712
713 static const struct inode_operations hugetlbfs_dir_inode_operations = {
714 .create = hugetlbfs_create,
715 .lookup = simple_lookup,
716 .link = simple_link,
717 .unlink = simple_unlink,
718 .symlink = hugetlbfs_symlink,
719 .mkdir = hugetlbfs_mkdir,
720 .rmdir = simple_rmdir,
721 .mknod = hugetlbfs_mknod,
722 .rename = simple_rename,
723 .setattr = hugetlbfs_setattr,
724 };
725
726 static const struct inode_operations hugetlbfs_inode_operations = {
727 .setattr = hugetlbfs_setattr,
728 };
729
730 static const struct super_operations hugetlbfs_ops = {
731 .alloc_inode = hugetlbfs_alloc_inode,
732 .destroy_inode = hugetlbfs_destroy_inode,
733 .evict_inode = hugetlbfs_evict_inode,
734 .statfs = hugetlbfs_statfs,
735 .put_super = hugetlbfs_put_super,
736 .show_options = generic_show_options,
737 };
738
739 static int
740 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
741 {
742 char *p, *rest;
743 substring_t args[MAX_OPT_ARGS];
744 int option;
745 unsigned long long size = 0;
746 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
747
748 if (!options)
749 return 0;
750
751 while ((p = strsep(&options, ",")) != NULL) {
752 int token;
753 if (!*p)
754 continue;
755
756 token = match_token(p, tokens, args);
757 switch (token) {
758 case Opt_uid:
759 if (match_int(&args[0], &option))
760 goto bad_val;
761 pconfig->uid = option;
762 break;
763
764 case Opt_gid:
765 if (match_int(&args[0], &option))
766 goto bad_val;
767 pconfig->gid = option;
768 break;
769
770 case Opt_mode:
771 if (match_octal(&args[0], &option))
772 goto bad_val;
773 pconfig->mode = option & 01777U;
774 break;
775
776 case Opt_size: {
777 /* memparse() will accept a K/M/G without a digit */
778 if (!isdigit(*args[0].from))
779 goto bad_val;
780 size = memparse(args[0].from, &rest);
781 setsize = SIZE_STD;
782 if (*rest == '%')
783 setsize = SIZE_PERCENT;
784 break;
785 }
786
787 case Opt_nr_inodes:
788 /* memparse() will accept a K/M/G without a digit */
789 if (!isdigit(*args[0].from))
790 goto bad_val;
791 pconfig->nr_inodes = memparse(args[0].from, &rest);
792 break;
793
794 case Opt_pagesize: {
795 unsigned long ps;
796 ps = memparse(args[0].from, &rest);
797 pconfig->hstate = size_to_hstate(ps);
798 if (!pconfig->hstate) {
799 printk(KERN_ERR
800 "hugetlbfs: Unsupported page size %lu MB\n",
801 ps >> 20);
802 return -EINVAL;
803 }
804 break;
805 }
806
807 default:
808 printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
809 p);
810 return -EINVAL;
811 break;
812 }
813 }
814
815 /* Do size after hstate is set up */
816 if (setsize > NO_SIZE) {
817 struct hstate *h = pconfig->hstate;
818 if (setsize == SIZE_PERCENT) {
819 size <<= huge_page_shift(h);
820 size *= h->max_huge_pages;
821 do_div(size, 100);
822 }
823 pconfig->nr_blocks = (size >> huge_page_shift(h));
824 }
825
826 return 0;
827
828 bad_val:
829 printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
830 args[0].from, p);
831 return -EINVAL;
832 }
833
834 static int
835 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
836 {
837 struct inode * inode;
838 struct dentry * root;
839 int ret;
840 struct hugetlbfs_config config;
841 struct hugetlbfs_sb_info *sbinfo;
842
843 save_mount_options(sb, data);
844
845 config.nr_blocks = -1; /* No limit on size by default */
846 config.nr_inodes = -1; /* No limit on number of inodes by default */
847 config.uid = current_fsuid();
848 config.gid = current_fsgid();
849 config.mode = 0755;
850 config.hstate = &default_hstate;
851 ret = hugetlbfs_parse_options(data, &config);
852 if (ret)
853 return ret;
854
855 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
856 if (!sbinfo)
857 return -ENOMEM;
858 sb->s_fs_info = sbinfo;
859 sbinfo->hstate = config.hstate;
860 spin_lock_init(&sbinfo->stat_lock);
861 sbinfo->max_inodes = config.nr_inodes;
862 sbinfo->free_inodes = config.nr_inodes;
863 sbinfo->spool = NULL;
864 if (config.nr_blocks != -1) {
865 sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
866 if (!sbinfo->spool)
867 goto out_free;
868 }
869 sb->s_maxbytes = MAX_LFS_FILESIZE;
870 sb->s_blocksize = huge_page_size(config.hstate);
871 sb->s_blocksize_bits = huge_page_shift(config.hstate);
872 sb->s_magic = HUGETLBFS_MAGIC;
873 sb->s_op = &hugetlbfs_ops;
874 sb->s_time_gran = 1;
875 inode = hugetlbfs_get_root(sb, &config);
876 if (!inode)
877 goto out_free;
878
879 root = d_alloc_root(inode);
880 if (!root) {
881 iput(inode);
882 goto out_free;
883 }
884 sb->s_root = root;
885 return 0;
886 out_free:
887 if (sbinfo->spool)
888 kfree(sbinfo->spool);
889 kfree(sbinfo);
890 return -ENOMEM;
891 }
892
893 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
894 int flags, const char *dev_name, void *data)
895 {
896 return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
897 }
898
899 static struct file_system_type hugetlbfs_fs_type = {
900 .name = "hugetlbfs",
901 .mount = hugetlbfs_mount,
902 .kill_sb = kill_litter_super,
903 };
904
905 static struct vfsmount *hugetlbfs_vfsmount;
906
907 static int can_do_hugetlb_shm(void)
908 {
909 return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
910 }
911
912 struct file *hugetlb_file_setup(const char *name, size_t size,
913 vm_flags_t acctflag,
914 struct user_struct **user, int creat_flags)
915 {
916 int error = -ENOMEM;
917 struct file *file;
918 struct inode *inode;
919 struct path path;
920 struct dentry *root;
921 struct qstr quick_string;
922
923 *user = NULL;
924 if (!hugetlbfs_vfsmount)
925 return ERR_PTR(-ENOENT);
926
927 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
928 *user = current_user();
929 if (user_shm_lock(size, *user)) {
930 printk_once(KERN_WARNING "Using mlock ulimits for SHM_HUGETLB is deprecated\n");
931 } else {
932 *user = NULL;
933 return ERR_PTR(-EPERM);
934 }
935 }
936
937 root = hugetlbfs_vfsmount->mnt_root;
938 quick_string.name = name;
939 quick_string.len = strlen(quick_string.name);
940 quick_string.hash = 0;
941 path.dentry = d_alloc(root, &quick_string);
942 if (!path.dentry)
943 goto out_shm_unlock;
944
945 path.mnt = mntget(hugetlbfs_vfsmount);
946 error = -ENOSPC;
947 inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0);
948 if (!inode)
949 goto out_dentry;
950
951 error = -ENOMEM;
952 if (hugetlb_reserve_pages(inode, 0,
953 size >> huge_page_shift(hstate_inode(inode)), NULL,
954 acctflag))
955 goto out_inode;
956
957 d_instantiate(path.dentry, inode);
958 inode->i_size = size;
959 clear_nlink(inode);
960
961 error = -ENFILE;
962 file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
963 &hugetlbfs_file_operations);
964 if (!file)
965 goto out_dentry; /* inode is already attached */
966
967 return file;
968
969 out_inode:
970 iput(inode);
971 out_dentry:
972 path_put(&path);
973 out_shm_unlock:
974 if (*user) {
975 user_shm_unlock(size, *user);
976 *user = NULL;
977 }
978 return ERR_PTR(error);
979 }
980
981 static int __init init_hugetlbfs_fs(void)
982 {
983 int error;
984 struct vfsmount *vfsmount;
985
986 error = bdi_init(&hugetlbfs_backing_dev_info);
987 if (error)
988 return error;
989
990 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
991 sizeof(struct hugetlbfs_inode_info),
992 0, 0, init_once);
993 if (hugetlbfs_inode_cachep == NULL)
994 goto out2;
995
996 error = register_filesystem(&hugetlbfs_fs_type);
997 if (error)
998 goto out;
999
1000 vfsmount = kern_mount(&hugetlbfs_fs_type);
1001
1002 if (!IS_ERR(vfsmount)) {
1003 hugetlbfs_vfsmount = vfsmount;
1004 return 0;
1005 }
1006
1007 error = PTR_ERR(vfsmount);
1008
1009 out:
1010 if (error)
1011 kmem_cache_destroy(hugetlbfs_inode_cachep);
1012 out2:
1013 bdi_destroy(&hugetlbfs_backing_dev_info);
1014 return error;
1015 }
1016
1017 static void __exit exit_hugetlbfs_fs(void)
1018 {
1019 kmem_cache_destroy(hugetlbfs_inode_cachep);
1020 kern_unmount(hugetlbfs_vfsmount);
1021 unregister_filesystem(&hugetlbfs_fs_type);
1022 bdi_destroy(&hugetlbfs_backing_dev_info);
1023 }
1024
1025 module_init(init_hugetlbfs_fs)
1026 module_exit(exit_hugetlbfs_fs)
1027
1028 MODULE_LICENSE("GPL");