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[S390] Fix comments in lowcore structure
[zen-stable.git] / fs / hugetlbfs / inode.c
blob9b800d97a68771b2299e978ebfdb003476e1c075
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/quotaops.h>
30 #include <linux/slab.h>
31 #include <linux/dnotify.h>
32 #include <linux/statfs.h>
33 #include <linux/security.h>
34
35 #include <asm/uaccess.h>
36
37 /* some random number */
38 #define HUGETLBFS_MAGIC 0x958458f6
39
40 static const struct super_operations hugetlbfs_ops;
41 static const struct address_space_operations hugetlbfs_aops;
42 const struct file_operations hugetlbfs_file_operations;
43 static const struct inode_operations hugetlbfs_dir_inode_operations;
44 static const struct inode_operations hugetlbfs_inode_operations;
45
46 static struct backing_dev_info hugetlbfs_backing_dev_info = {
47 .ra_pages = 0, /* No readahead */
48 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
49 };
50
51 int sysctl_hugetlb_shm_group;
52
53 enum {
54 Opt_size, Opt_nr_inodes,
55 Opt_mode, Opt_uid, Opt_gid,
56 Opt_pagesize,
57 Opt_err,
58 };
59
60 static const match_table_t tokens = {
61 {Opt_size, "size=%s"},
62 {Opt_nr_inodes, "nr_inodes=%s"},
63 {Opt_mode, "mode=%o"},
64 {Opt_uid, "uid=%u"},
65 {Opt_gid, "gid=%u"},
66 {Opt_pagesize, "pagesize=%s"},
67 {Opt_err, NULL},
68 };
69
70 static void huge_pagevec_release(struct pagevec *pvec)
71 {
72 int i;
73
74 for (i = 0; i < pagevec_count(pvec); ++i)
75 put_page(pvec->pages[i]);
76
77 pagevec_reinit(pvec);
78 }
79
80 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
81 {
82 struct inode *inode = file->f_path.dentry->d_inode;
83 loff_t len, vma_len;
84 int ret;
85 struct hstate *h = hstate_file(file);
86
87 /*
88 * vma address alignment (but not the pgoff alignment) has
89 * already been checked by prepare_hugepage_range. If you add
90 * any error returns here, do so after setting VM_HUGETLB, so
91 * is_vm_hugetlb_page tests below unmap_region go the right
92 * way when do_mmap_pgoff unwinds (may be important on powerpc
93 * and ia64).
94 */
95 vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
96 vma->vm_ops = &hugetlb_vm_ops;
97
98 if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
99 return -EINVAL;
100
101 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
102
103 mutex_lock(&inode->i_mutex);
104 file_accessed(file);
105
106 ret = -ENOMEM;
107 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
108
109 if (hugetlb_reserve_pages(inode,
110 vma->vm_pgoff >> huge_page_order(h),
111 len >> huge_page_shift(h), vma,
112 vma->vm_flags))
113 goto out;
114
115 ret = 0;
116 hugetlb_prefault_arch_hook(vma->vm_mm);
117 if (vma->vm_flags & VM_WRITE && inode->i_size < len)
118 inode->i_size = len;
119 out:
120 mutex_unlock(&inode->i_mutex);
121
122 return ret;
123 }
124
125 /*
126 * Called under down_write(mmap_sem).
127 */
128
129 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
130 static unsigned long
131 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
132 unsigned long len, unsigned long pgoff, unsigned long flags)
133 {
134 struct mm_struct *mm = current->mm;
135 struct vm_area_struct *vma;
136 unsigned long start_addr;
137 struct hstate *h = hstate_file(file);
138
139 if (len & ~huge_page_mask(h))
140 return -EINVAL;
141 if (len > TASK_SIZE)
142 return -ENOMEM;
143
144 if (flags & MAP_FIXED) {
145 if (prepare_hugepage_range(file, addr, len))
146 return -EINVAL;
147 return addr;
148 }
149
150 if (addr) {
151 addr = ALIGN(addr, huge_page_size(h));
152 vma = find_vma(mm, addr);
153 if (TASK_SIZE - len >= addr &&
154 (!vma || addr + len <= vma->vm_start))
155 return addr;
156 }
157
158 start_addr = mm->free_area_cache;
159
160 if (len <= mm->cached_hole_size)
161 start_addr = TASK_UNMAPPED_BASE;
162
163 full_search:
164 addr = ALIGN(start_addr, huge_page_size(h));
165
166 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
167 /* At this point: (!vma || addr < vma->vm_end). */
168 if (TASK_SIZE - len < addr) {
169 /*
170 * Start a new search - just in case we missed
171 * some holes.
172 */
173 if (start_addr != TASK_UNMAPPED_BASE) {
174 start_addr = TASK_UNMAPPED_BASE;
175 goto full_search;
176 }
177 return -ENOMEM;
178 }
179
180 if (!vma || addr + len <= vma->vm_start)
181 return addr;
182 addr = ALIGN(vma->vm_end, huge_page_size(h));
183 }
184 }
185 #endif
186
187 static int
188 hugetlbfs_read_actor(struct page *page, unsigned long offset,
189 char __user *buf, unsigned long count,
190 unsigned long size)
191 {
192 char *kaddr;
193 unsigned long left, copied = 0;
194 int i, chunksize;
195
196 if (size > count)
197 size = count;
198
199 /* Find which 4k chunk and offset with in that chunk */
200 i = offset >> PAGE_CACHE_SHIFT;
201 offset = offset & ~PAGE_CACHE_MASK;
202
203 while (size) {
204 chunksize = PAGE_CACHE_SIZE;
205 if (offset)
206 chunksize -= offset;
207 if (chunksize > size)
208 chunksize = size;
209 kaddr = kmap(&page[i]);
210 left = __copy_to_user(buf, kaddr + offset, chunksize);
211 kunmap(&page[i]);
212 if (left) {
213 copied += (chunksize - left);
214 break;
215 }
216 offset = 0;
217 size -= chunksize;
218 buf += chunksize;
219 copied += chunksize;
220 i++;
221 }
222 return copied ? copied : -EFAULT;
223 }
224
225 /*
226 * Support for read() - Find the page attached to f_mapping and copy out the
227 * data. Its *very* similar to do_generic_mapping_read(), we can't use that
228 * since it has PAGE_CACHE_SIZE assumptions.
229 */
230 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
231 size_t len, loff_t *ppos)
232 {
233 struct hstate *h = hstate_file(filp);
234 struct address_space *mapping = filp->f_mapping;
235 struct inode *inode = mapping->host;
236 unsigned long index = *ppos >> huge_page_shift(h);
237 unsigned long offset = *ppos & ~huge_page_mask(h);
238 unsigned long end_index;
239 loff_t isize;
240 ssize_t retval = 0;
241
242 mutex_lock(&inode->i_mutex);
243
244 /* validate length */
245 if (len == 0)
246 goto out;
247
248 isize = i_size_read(inode);
249 if (!isize)
250 goto out;
251
252 end_index = (isize - 1) >> huge_page_shift(h);
253 for (;;) {
254 struct page *page;
255 unsigned long nr, ret;
256 int ra;
257
258 /* nr is the maximum number of bytes to copy from this page */
259 nr = huge_page_size(h);
260 if (index >= end_index) {
261 if (index > end_index)
262 goto out;
263 nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
264 if (nr <= offset) {
265 goto out;
266 }
267 }
268 nr = nr - offset;
269
270 /* Find the page */
271 page = find_get_page(mapping, index);
272 if (unlikely(page == NULL)) {
273 /*
274 * We have a HOLE, zero out the user-buffer for the
275 * length of the hole or request.
276 */
277 ret = len < nr ? len : nr;
278 if (clear_user(buf, ret))
279 ra = -EFAULT;
280 else
281 ra = 0;
282 } else {
283 /*
284 * We have the page, copy it to user space buffer.
285 */
286 ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
287 ret = ra;
288 }
289 if (ra < 0) {
290 if (retval == 0)
291 retval = ra;
292 if (page)
293 page_cache_release(page);
294 goto out;
295 }
296
297 offset += ret;
298 retval += ret;
299 len -= ret;
300 index += offset >> huge_page_shift(h);
301 offset &= ~huge_page_mask(h);
302
303 if (page)
304 page_cache_release(page);
305
306 /* short read or no more work */
307 if ((ret != nr) || (len == 0))
308 break;
309 }
310 out:
311 *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
312 mutex_unlock(&inode->i_mutex);
313 return retval;
314 }
315
316 /*
317 * Read a page. Again trivial. If it didn't already exist
318 * in the page cache, it is zero-filled.
319 */
320 static int hugetlbfs_readpage(struct file *file, struct page * page)
321 {
322 unlock_page(page);
323 return -EINVAL;
324 }
325
326 static int hugetlbfs_write_begin(struct file *file,
327 struct address_space *mapping,
328 loff_t pos, unsigned len, unsigned flags,
329 struct page **pagep, void **fsdata)
330 {
331 return -EINVAL;
332 }
333
334 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
335 loff_t pos, unsigned len, unsigned copied,
336 struct page *page, void *fsdata)
337 {
338 BUG();
339 return -EINVAL;
340 }
341
342 static void truncate_huge_page(struct page *page)
343 {
344 cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
345 ClearPageUptodate(page);
346 remove_from_page_cache(page);
347 put_page(page);
348 }
349
350 static void truncate_hugepages(struct inode *inode, loff_t lstart)
351 {
352 struct hstate *h = hstate_inode(inode);
353 struct address_space *mapping = &inode->i_data;
354 const pgoff_t start = lstart >> huge_page_shift(h);
355 struct pagevec pvec;
356 pgoff_t next;
357 int i, freed = 0;
358
359 pagevec_init(&pvec, 0);
360 next = start;
361 while (1) {
362 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
363 if (next == start)
364 break;
365 next = start;
366 continue;
367 }
368
369 for (i = 0; i < pagevec_count(&pvec); ++i) {
370 struct page *page = pvec.pages[i];
371
372 lock_page(page);
373 if (page->index > next)
374 next = page->index;
375 ++next;
376 truncate_huge_page(page);
377 unlock_page(page);
378 freed++;
379 }
380 huge_pagevec_release(&pvec);
381 }
382 BUG_ON(!lstart && mapping->nrpages);
383 hugetlb_unreserve_pages(inode, start, freed);
384 }
385
386 static void hugetlbfs_delete_inode(struct inode *inode)
387 {
388 truncate_hugepages(inode, 0);
389 clear_inode(inode);
390 }
391
392 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
393 {
394 struct super_block *sb = inode->i_sb;
395
396 if (!hlist_unhashed(&inode->i_hash)) {
397 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
398 list_move(&inode->i_list, &inode_unused);
399 inodes_stat.nr_unused++;
400 if (!sb || (sb->s_flags & MS_ACTIVE)) {
401 spin_unlock(&inode_lock);
402 return;
403 }
404 inode->i_state |= I_WILL_FREE;
405 spin_unlock(&inode_lock);
406 /*
407 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
408 * in our backing_dev_info.
409 */
410 write_inode_now(inode, 1);
411 spin_lock(&inode_lock);
412 inode->i_state &= ~I_WILL_FREE;
413 inodes_stat.nr_unused--;
414 hlist_del_init(&inode->i_hash);
415 }
416 list_del_init(&inode->i_list);
417 list_del_init(&inode->i_sb_list);
418 inode->i_state |= I_FREEING;
419 inodes_stat.nr_inodes--;
420 spin_unlock(&inode_lock);
421 truncate_hugepages(inode, 0);
422 clear_inode(inode);
423 destroy_inode(inode);
424 }
425
426 static void hugetlbfs_drop_inode(struct inode *inode)
427 {
428 if (!inode->i_nlink)
429 generic_delete_inode(inode);
430 else
431 hugetlbfs_forget_inode(inode);
432 }
433
434 static inline void
435 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
436 {
437 struct vm_area_struct *vma;
438 struct prio_tree_iter iter;
439
440 vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
441 unsigned long v_offset;
442
443 /*
444 * Can the expression below overflow on 32-bit arches?
445 * No, because the prio_tree returns us only those vmas
446 * which overlap the truncated area starting at pgoff,
447 * and no vma on a 32-bit arch can span beyond the 4GB.
448 */
449 if (vma->vm_pgoff < pgoff)
450 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
451 else
452 v_offset = 0;
453
454 __unmap_hugepage_range(vma,
455 vma->vm_start + v_offset, vma->vm_end, NULL);
456 }
457 }
458
459 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
460 {
461 pgoff_t pgoff;
462 struct address_space *mapping = inode->i_mapping;
463 struct hstate *h = hstate_inode(inode);
464
465 BUG_ON(offset & ~huge_page_mask(h));
466 pgoff = offset >> PAGE_SHIFT;
467
468 i_size_write(inode, offset);
469 spin_lock(&mapping->i_mmap_lock);
470 if (!prio_tree_empty(&mapping->i_mmap))
471 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
472 spin_unlock(&mapping->i_mmap_lock);
473 truncate_hugepages(inode, offset);
474 return 0;
475 }
476
477 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
478 {
479 struct inode *inode = dentry->d_inode;
480 struct hstate *h = hstate_inode(inode);
481 int error;
482 unsigned int ia_valid = attr->ia_valid;
483
484 BUG_ON(!inode);
485
486 error = inode_change_ok(inode, attr);
487 if (error)
488 goto out;
489
490 if (ia_valid & ATTR_SIZE) {
491 error = -EINVAL;
492 if (!(attr->ia_size & ~huge_page_mask(h)))
493 error = hugetlb_vmtruncate(inode, attr->ia_size);
494 if (error)
495 goto out;
496 attr->ia_valid &= ~ATTR_SIZE;
497 }
498 error = inode_setattr(inode, attr);
499 out:
500 return error;
501 }
502
503 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
504 gid_t gid, int mode, dev_t dev)
505 {
506 struct inode *inode;
507
508 inode = new_inode(sb);
509 if (inode) {
510 struct hugetlbfs_inode_info *info;
511 inode->i_mode = mode;
512 inode->i_uid = uid;
513 inode->i_gid = gid;
514 inode->i_mapping->a_ops = &hugetlbfs_aops;
515 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
516 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
517 INIT_LIST_HEAD(&inode->i_mapping->private_list);
518 info = HUGETLBFS_I(inode);
519 mpol_shared_policy_init(&info->policy, NULL);
520 switch (mode & S_IFMT) {
521 default:
522 init_special_inode(inode, mode, dev);
523 break;
524 case S_IFREG:
525 inode->i_op = &hugetlbfs_inode_operations;
526 inode->i_fop = &hugetlbfs_file_operations;
527 break;
528 case S_IFDIR:
529 inode->i_op = &hugetlbfs_dir_inode_operations;
530 inode->i_fop = &simple_dir_operations;
531
532 /* directory inodes start off with i_nlink == 2 (for "." entry) */
533 inc_nlink(inode);
534 break;
535 case S_IFLNK:
536 inode->i_op = &page_symlink_inode_operations;
537 break;
538 }
539 }
540 return inode;
541 }
542
543 /*
544 * File creation. Allocate an inode, and we're done..
545 */
546 static int hugetlbfs_mknod(struct inode *dir,
547 struct dentry *dentry, int mode, dev_t dev)
548 {
549 struct inode *inode;
550 int error = -ENOSPC;
551 gid_t gid;
552
553 if (dir->i_mode & S_ISGID) {
554 gid = dir->i_gid;
555 if (S_ISDIR(mode))
556 mode |= S_ISGID;
557 } else {
558 gid = current_fsgid();
559 }
560 inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
561 if (inode) {
562 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
563 d_instantiate(dentry, inode);
564 dget(dentry); /* Extra count - pin the dentry in core */
565 error = 0;
566 }
567 return error;
568 }
569
570 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
571 {
572 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
573 if (!retval)
574 inc_nlink(dir);
575 return retval;
576 }
577
578 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
579 {
580 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
581 }
582
583 static int hugetlbfs_symlink(struct inode *dir,
584 struct dentry *dentry, const char *symname)
585 {
586 struct inode *inode;
587 int error = -ENOSPC;
588 gid_t gid;
589
590 if (dir->i_mode & S_ISGID)
591 gid = dir->i_gid;
592 else
593 gid = current_fsgid();
594
595 inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
596 gid, S_IFLNK|S_IRWXUGO, 0);
597 if (inode) {
598 int l = strlen(symname)+1;
599 error = page_symlink(inode, symname, l);
600 if (!error) {
601 d_instantiate(dentry, inode);
602 dget(dentry);
603 } else
604 iput(inode);
605 }
606 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
607
608 return error;
609 }
610
611 /*
612 * mark the head page dirty
613 */
614 static int hugetlbfs_set_page_dirty(struct page *page)
615 {
616 struct page *head = compound_head(page);
617
618 SetPageDirty(head);
619 return 0;
620 }
621
622 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
623 {
624 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
625 struct hstate *h = hstate_inode(dentry->d_inode);
626
627 buf->f_type = HUGETLBFS_MAGIC;
628 buf->f_bsize = huge_page_size(h);
629 if (sbinfo) {
630 spin_lock(&sbinfo->stat_lock);
631 /* If no limits set, just report 0 for max/free/used
632 * blocks, like simple_statfs() */
633 if (sbinfo->max_blocks >= 0) {
634 buf->f_blocks = sbinfo->max_blocks;
635 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
636 buf->f_files = sbinfo->max_inodes;
637 buf->f_ffree = sbinfo->free_inodes;
638 }
639 spin_unlock(&sbinfo->stat_lock);
640 }
641 buf->f_namelen = NAME_MAX;
642 return 0;
643 }
644
645 static void hugetlbfs_put_super(struct super_block *sb)
646 {
647 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
648
649 if (sbi) {
650 sb->s_fs_info = NULL;
651 kfree(sbi);
652 }
653 }
654
655 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
656 {
657 if (sbinfo->free_inodes >= 0) {
658 spin_lock(&sbinfo->stat_lock);
659 if (unlikely(!sbinfo->free_inodes)) {
660 spin_unlock(&sbinfo->stat_lock);
661 return 0;
662 }
663 sbinfo->free_inodes--;
664 spin_unlock(&sbinfo->stat_lock);
665 }
666
667 return 1;
668 }
669
670 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
671 {
672 if (sbinfo->free_inodes >= 0) {
673 spin_lock(&sbinfo->stat_lock);
674 sbinfo->free_inodes++;
675 spin_unlock(&sbinfo->stat_lock);
676 }
677 }
678
679
680 static struct kmem_cache *hugetlbfs_inode_cachep;
681
682 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
683 {
684 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
685 struct hugetlbfs_inode_info *p;
686
687 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
688 return NULL;
689 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
690 if (unlikely(!p)) {
691 hugetlbfs_inc_free_inodes(sbinfo);
692 return NULL;
693 }
694 return &p->vfs_inode;
695 }
696
697 static void hugetlbfs_destroy_inode(struct inode *inode)
698 {
699 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
700 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
701 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
702 }
703
704 static const struct address_space_operations hugetlbfs_aops = {
705 .readpage = hugetlbfs_readpage,
706 .write_begin = hugetlbfs_write_begin,
707 .write_end = hugetlbfs_write_end,
708 .set_page_dirty = hugetlbfs_set_page_dirty,
709 };
710
711
712 static void init_once(void *foo)
713 {
714 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
715
716 inode_init_once(&ei->vfs_inode);
717 }
718
719 const struct file_operations hugetlbfs_file_operations = {
720 .read = hugetlbfs_read,
721 .mmap = hugetlbfs_file_mmap,
722 .fsync = simple_sync_file,
723 .get_unmapped_area = hugetlb_get_unmapped_area,
724 };
725
726 static const struct inode_operations hugetlbfs_dir_inode_operations = {
727 .create = hugetlbfs_create,
728 .lookup = simple_lookup,
729 .link = simple_link,
730 .unlink = simple_unlink,
731 .symlink = hugetlbfs_symlink,
732 .mkdir = hugetlbfs_mkdir,
733 .rmdir = simple_rmdir,
734 .mknod = hugetlbfs_mknod,
735 .rename = simple_rename,
736 .setattr = hugetlbfs_setattr,
737 };
738
739 static const struct inode_operations hugetlbfs_inode_operations = {
740 .setattr = hugetlbfs_setattr,
741 };
742
743 static const struct super_operations hugetlbfs_ops = {
744 .alloc_inode = hugetlbfs_alloc_inode,
745 .destroy_inode = hugetlbfs_destroy_inode,
746 .statfs = hugetlbfs_statfs,
747 .delete_inode = hugetlbfs_delete_inode,
748 .drop_inode = hugetlbfs_drop_inode,
749 .put_super = hugetlbfs_put_super,
750 .show_options = generic_show_options,
751 };
752
753 static int
754 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
755 {
756 char *p, *rest;
757 substring_t args[MAX_OPT_ARGS];
758 int option;
759 unsigned long long size = 0;
760 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
761
762 if (!options)
763 return 0;
764
765 while ((p = strsep(&options, ",")) != NULL) {
766 int token;
767 if (!*p)
768 continue;
769
770 token = match_token(p, tokens, args);
771 switch (token) {
772 case Opt_uid:
773 if (match_int(&args[0], &option))
774 goto bad_val;
775 pconfig->uid = option;
776 break;
777
778 case Opt_gid:
779 if (match_int(&args[0], &option))
780 goto bad_val;
781 pconfig->gid = option;
782 break;
783
784 case Opt_mode:
785 if (match_octal(&args[0], &option))
786 goto bad_val;
787 pconfig->mode = option & 01777U;
788 break;
789
790 case Opt_size: {
791 /* memparse() will accept a K/M/G without a digit */
792 if (!isdigit(*args[0].from))
793 goto bad_val;
794 size = memparse(args[0].from, &rest);
795 setsize = SIZE_STD;
796 if (*rest == '%')
797 setsize = SIZE_PERCENT;
798 break;
799 }
800
801 case Opt_nr_inodes:
802 /* memparse() will accept a K/M/G without a digit */
803 if (!isdigit(*args[0].from))
804 goto bad_val;
805 pconfig->nr_inodes = memparse(args[0].from, &rest);
806 break;
807
808 case Opt_pagesize: {
809 unsigned long ps;
810 ps = memparse(args[0].from, &rest);
811 pconfig->hstate = size_to_hstate(ps);
812 if (!pconfig->hstate) {
813 printk(KERN_ERR
814 "hugetlbfs: Unsupported page size %lu MB\n",
815 ps >> 20);
816 return -EINVAL;
817 }
818 break;
819 }
820
821 default:
822 printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
823 p);
824 return -EINVAL;
825 break;
826 }
827 }
828
829 /* Do size after hstate is set up */
830 if (setsize > NO_SIZE) {
831 struct hstate *h = pconfig->hstate;
832 if (setsize == SIZE_PERCENT) {
833 size <<= huge_page_shift(h);
834 size *= h->max_huge_pages;
835 do_div(size, 100);
836 }
837 pconfig->nr_blocks = (size >> huge_page_shift(h));
838 }
839
840 return 0;
841
842 bad_val:
843 printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
844 args[0].from, p);
845 return 1;
846 }
847
848 static int
849 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
850 {
851 struct inode * inode;
852 struct dentry * root;
853 int ret;
854 struct hugetlbfs_config config;
855 struct hugetlbfs_sb_info *sbinfo;
856
857 save_mount_options(sb, data);
858
859 config.nr_blocks = -1; /* No limit on size by default */
860 config.nr_inodes = -1; /* No limit on number of inodes by default */
861 config.uid = current_fsuid();
862 config.gid = current_fsgid();
863 config.mode = 0755;
864 config.hstate = &default_hstate;
865 ret = hugetlbfs_parse_options(data, &config);
866 if (ret)
867 return ret;
868
869 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
870 if (!sbinfo)
871 return -ENOMEM;
872 sb->s_fs_info = sbinfo;
873 sbinfo->hstate = config.hstate;
874 spin_lock_init(&sbinfo->stat_lock);
875 sbinfo->max_blocks = config.nr_blocks;
876 sbinfo->free_blocks = config.nr_blocks;
877 sbinfo->max_inodes = config.nr_inodes;
878 sbinfo->free_inodes = config.nr_inodes;
879 sb->s_maxbytes = MAX_LFS_FILESIZE;
880 sb->s_blocksize = huge_page_size(config.hstate);
881 sb->s_blocksize_bits = huge_page_shift(config.hstate);
882 sb->s_magic = HUGETLBFS_MAGIC;
883 sb->s_op = &hugetlbfs_ops;
884 sb->s_time_gran = 1;
885 inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
886 S_IFDIR | config.mode, 0);
887 if (!inode)
888 goto out_free;
889
890 root = d_alloc_root(inode);
891 if (!root) {
892 iput(inode);
893 goto out_free;
894 }
895 sb->s_root = root;
896 return 0;
897 out_free:
898 kfree(sbinfo);
899 return -ENOMEM;
900 }
901
902 int hugetlb_get_quota(struct address_space *mapping, long delta)
903 {
904 int ret = 0;
905 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
906
907 if (sbinfo->free_blocks > -1) {
908 spin_lock(&sbinfo->stat_lock);
909 if (sbinfo->free_blocks - delta >= 0)
910 sbinfo->free_blocks -= delta;
911 else
912 ret = -ENOMEM;
913 spin_unlock(&sbinfo->stat_lock);
914 }
915
916 return ret;
917 }
918
919 void hugetlb_put_quota(struct address_space *mapping, long delta)
920 {
921 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
922
923 if (sbinfo->free_blocks > -1) {
924 spin_lock(&sbinfo->stat_lock);
925 sbinfo->free_blocks += delta;
926 spin_unlock(&sbinfo->stat_lock);
927 }
928 }
929
930 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
931 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
932 {
933 return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
934 }
935
936 static struct file_system_type hugetlbfs_fs_type = {
937 .name = "hugetlbfs",
938 .get_sb = hugetlbfs_get_sb,
939 .kill_sb = kill_litter_super,
940 };
941
942 static struct vfsmount *hugetlbfs_vfsmount;
943
944 static int can_do_hugetlb_shm(void)
945 {
946 return likely(capable(CAP_IPC_LOCK) ||
947 in_group_p(sysctl_hugetlb_shm_group) ||
948 can_do_mlock());
949 }
950
951 struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag)
952 {
953 int error = -ENOMEM;
954 struct file *file;
955 struct inode *inode;
956 struct dentry *dentry, *root;
957 struct qstr quick_string;
958 struct user_struct *user = current_user();
959
960 if (!hugetlbfs_vfsmount)
961 return ERR_PTR(-ENOENT);
962
963 if (!can_do_hugetlb_shm())
964 return ERR_PTR(-EPERM);
965
966 if (!user_shm_lock(size, user))
967 return ERR_PTR(-ENOMEM);
968
969 root = hugetlbfs_vfsmount->mnt_root;
970 quick_string.name = name;
971 quick_string.len = strlen(quick_string.name);
972 quick_string.hash = 0;
973 dentry = d_alloc(root, &quick_string);
974 if (!dentry)
975 goto out_shm_unlock;
976
977 error = -ENOSPC;
978 inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
979 current_fsgid(), S_IFREG | S_IRWXUGO, 0);
980 if (!inode)
981 goto out_dentry;
982
983 error = -ENOMEM;
984 if (hugetlb_reserve_pages(inode, 0,
985 size >> huge_page_shift(hstate_inode(inode)), NULL,
986 acctflag))
987 goto out_inode;
988
989 d_instantiate(dentry, inode);
990 inode->i_size = size;
991 inode->i_nlink = 0;
992
993 error = -ENFILE;
994 file = alloc_file(hugetlbfs_vfsmount, dentry,
995 FMODE_WRITE | FMODE_READ,
996 &hugetlbfs_file_operations);
997 if (!file)
998 goto out_dentry; /* inode is already attached */
999
1000 return file;
1001
1002 out_inode:
1003 iput(inode);
1004 out_dentry:
1005 dput(dentry);
1006 out_shm_unlock:
1007 user_shm_unlock(size, user);
1008 return ERR_PTR(error);
1009 }
1010
1011 static int __init init_hugetlbfs_fs(void)
1012 {
1013 int error;
1014 struct vfsmount *vfsmount;
1015
1016 error = bdi_init(&hugetlbfs_backing_dev_info);
1017 if (error)
1018 return error;
1019
1020 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1021 sizeof(struct hugetlbfs_inode_info),
1022 0, 0, init_once);
1023 if (hugetlbfs_inode_cachep == NULL)
1024 goto out2;
1025
1026 error = register_filesystem(&hugetlbfs_fs_type);
1027 if (error)
1028 goto out;
1029
1030 vfsmount = kern_mount(&hugetlbfs_fs_type);
1031
1032 if (!IS_ERR(vfsmount)) {
1033 hugetlbfs_vfsmount = vfsmount;
1034 return 0;
1035 }
1036
1037 error = PTR_ERR(vfsmount);
1038
1039 out:
1040 if (error)
1041 kmem_cache_destroy(hugetlbfs_inode_cachep);
1042 out2:
1043 bdi_destroy(&hugetlbfs_backing_dev_info);
1044 return error;
1045 }
1046
1047 static void __exit exit_hugetlbfs_fs(void)
1048 {
1049 kmem_cache_destroy(hugetlbfs_inode_cachep);
1050 unregister_filesystem(&hugetlbfs_fs_type);
1051 bdi_destroy(&hugetlbfs_backing_dev_info);
1052 }
1053
1054 module_init(init_hugetlbfs_fs)
1055 module_exit(exit_hugetlbfs_fs)
1056
1057 MODULE_LICENSE("GPL");