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hugetlb: reserve huge pages for reliable MAP_PRIVATE hugetlbfs mappings until fork()
[linux-2.6/mini2440.git] / fs / hugetlbfs / inode.c
blob1576bbecd084575e2cb97fffe6846c2039309dd5
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_err,
57 };
58
59 static 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_err, NULL},
66 };
67
68 static void huge_pagevec_release(struct pagevec *pvec)
69 {
70 int i;
71
72 for (i = 0; i < pagevec_count(pvec); ++i)
73 put_page(pvec->pages[i]);
74
75 pagevec_reinit(pvec);
76 }
77
78 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
79 {
80 struct inode *inode = file->f_path.dentry->d_inode;
81 loff_t len, vma_len;
82 int ret;
83
84 /*
85 * vma address alignment (but not the pgoff alignment) has
86 * already been checked by prepare_hugepage_range. If you add
87 * any error returns here, do so after setting VM_HUGETLB, so
88 * is_vm_hugetlb_page tests below unmap_region go the right
89 * way when do_mmap_pgoff unwinds (may be important on powerpc
90 * and ia64).
91 */
92 vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
93 vma->vm_ops = &hugetlb_vm_ops;
94
95 if (vma->vm_pgoff & ~(HPAGE_MASK >> PAGE_SHIFT))
96 return -EINVAL;
97
98 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
99
100 mutex_lock(&inode->i_mutex);
101 file_accessed(file);
102
103 ret = -ENOMEM;
104 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
105
106 if (hugetlb_reserve_pages(inode,
107 vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
108 len >> HPAGE_SHIFT, vma))
109 goto out;
110
111 ret = 0;
112 hugetlb_prefault_arch_hook(vma->vm_mm);
113 if (vma->vm_flags & VM_WRITE && inode->i_size < len)
114 inode->i_size = len;
115 out:
116 mutex_unlock(&inode->i_mutex);
117
118 return ret;
119 }
120
121 /*
122 * Called under down_write(mmap_sem).
123 */
124
125 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
126 static unsigned long
127 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
128 unsigned long len, unsigned long pgoff, unsigned long flags)
129 {
130 struct mm_struct *mm = current->mm;
131 struct vm_area_struct *vma;
132 unsigned long start_addr;
133
134 if (len & ~HPAGE_MASK)
135 return -EINVAL;
136 if (len > TASK_SIZE)
137 return -ENOMEM;
138
139 if (flags & MAP_FIXED) {
140 if (prepare_hugepage_range(addr, len))
141 return -EINVAL;
142 return addr;
143 }
144
145 if (addr) {
146 addr = ALIGN(addr, HPAGE_SIZE);
147 vma = find_vma(mm, addr);
148 if (TASK_SIZE - len >= addr &&
149 (!vma || addr + len <= vma->vm_start))
150 return addr;
151 }
152
153 start_addr = mm->free_area_cache;
154
155 if (len <= mm->cached_hole_size)
156 start_addr = TASK_UNMAPPED_BASE;
157
158 full_search:
159 addr = ALIGN(start_addr, HPAGE_SIZE);
160
161 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
162 /* At this point: (!vma || addr < vma->vm_end). */
163 if (TASK_SIZE - len < addr) {
164 /*
165 * Start a new search - just in case we missed
166 * some holes.
167 */
168 if (start_addr != TASK_UNMAPPED_BASE) {
169 start_addr = TASK_UNMAPPED_BASE;
170 goto full_search;
171 }
172 return -ENOMEM;
173 }
174
175 if (!vma || addr + len <= vma->vm_start)
176 return addr;
177 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
178 }
179 }
180 #endif
181
182 static int
183 hugetlbfs_read_actor(struct page *page, unsigned long offset,
184 char __user *buf, unsigned long count,
185 unsigned long size)
186 {
187 char *kaddr;
188 unsigned long left, copied = 0;
189 int i, chunksize;
190
191 if (size > count)
192 size = count;
193
194 /* Find which 4k chunk and offset with in that chunk */
195 i = offset >> PAGE_CACHE_SHIFT;
196 offset = offset & ~PAGE_CACHE_MASK;
197
198 while (size) {
199 chunksize = PAGE_CACHE_SIZE;
200 if (offset)
201 chunksize -= offset;
202 if (chunksize > size)
203 chunksize = size;
204 kaddr = kmap(&page[i]);
205 left = __copy_to_user(buf, kaddr + offset, chunksize);
206 kunmap(&page[i]);
207 if (left) {
208 copied += (chunksize - left);
209 break;
210 }
211 offset = 0;
212 size -= chunksize;
213 buf += chunksize;
214 copied += chunksize;
215 i++;
216 }
217 return copied ? copied : -EFAULT;
218 }
219
220 /*
221 * Support for read() - Find the page attached to f_mapping and copy out the
222 * data. Its *very* similar to do_generic_mapping_read(), we can't use that
223 * since it has PAGE_CACHE_SIZE assumptions.
224 */
225 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
226 size_t len, loff_t *ppos)
227 {
228 struct address_space *mapping = filp->f_mapping;
229 struct inode *inode = mapping->host;
230 unsigned long index = *ppos >> HPAGE_SHIFT;
231 unsigned long offset = *ppos & ~HPAGE_MASK;
232 unsigned long end_index;
233 loff_t isize;
234 ssize_t retval = 0;
235
236 mutex_lock(&inode->i_mutex);
237
238 /* validate length */
239 if (len == 0)
240 goto out;
241
242 isize = i_size_read(inode);
243 if (!isize)
244 goto out;
245
246 end_index = (isize - 1) >> HPAGE_SHIFT;
247 for (;;) {
248 struct page *page;
249 int nr, ret;
250
251 /* nr is the maximum number of bytes to copy from this page */
252 nr = HPAGE_SIZE;
253 if (index >= end_index) {
254 if (index > end_index)
255 goto out;
256 nr = ((isize - 1) & ~HPAGE_MASK) + 1;
257 if (nr <= offset) {
258 goto out;
259 }
260 }
261 nr = nr - offset;
262
263 /* Find the page */
264 page = find_get_page(mapping, index);
265 if (unlikely(page == NULL)) {
266 /*
267 * We have a HOLE, zero out the user-buffer for the
268 * length of the hole or request.
269 */
270 ret = len < nr ? len : nr;
271 if (clear_user(buf, ret))
272 ret = -EFAULT;
273 } else {
274 /*
275 * We have the page, copy it to user space buffer.
276 */
277 ret = hugetlbfs_read_actor(page, offset, buf, len, nr);
278 }
279 if (ret < 0) {
280 if (retval == 0)
281 retval = ret;
282 if (page)
283 page_cache_release(page);
284 goto out;
285 }
286
287 offset += ret;
288 retval += ret;
289 len -= ret;
290 index += offset >> HPAGE_SHIFT;
291 offset &= ~HPAGE_MASK;
292
293 if (page)
294 page_cache_release(page);
295
296 /* short read or no more work */
297 if ((ret != nr) || (len == 0))
298 break;
299 }
300 out:
301 *ppos = ((loff_t)index << HPAGE_SHIFT) + offset;
302 mutex_unlock(&inode->i_mutex);
303 return retval;
304 }
305
306 /*
307 * Read a page. Again trivial. If it didn't already exist
308 * in the page cache, it is zero-filled.
309 */
310 static int hugetlbfs_readpage(struct file *file, struct page * page)
311 {
312 unlock_page(page);
313 return -EINVAL;
314 }
315
316 static int hugetlbfs_write_begin(struct file *file,
317 struct address_space *mapping,
318 loff_t pos, unsigned len, unsigned flags,
319 struct page **pagep, void **fsdata)
320 {
321 return -EINVAL;
322 }
323
324 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
325 loff_t pos, unsigned len, unsigned copied,
326 struct page *page, void *fsdata)
327 {
328 BUG();
329 return -EINVAL;
330 }
331
332 static void truncate_huge_page(struct page *page)
333 {
334 cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
335 ClearPageUptodate(page);
336 remove_from_page_cache(page);
337 put_page(page);
338 }
339
340 static void truncate_hugepages(struct inode *inode, loff_t lstart)
341 {
342 struct address_space *mapping = &inode->i_data;
343 const pgoff_t start = lstart >> HPAGE_SHIFT;
344 struct pagevec pvec;
345 pgoff_t next;
346 int i, freed = 0;
347
348 pagevec_init(&pvec, 0);
349 next = start;
350 while (1) {
351 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
352 if (next == start)
353 break;
354 next = start;
355 continue;
356 }
357
358 for (i = 0; i < pagevec_count(&pvec); ++i) {
359 struct page *page = pvec.pages[i];
360
361 lock_page(page);
362 if (page->index > next)
363 next = page->index;
364 ++next;
365 truncate_huge_page(page);
366 unlock_page(page);
367 freed++;
368 }
369 huge_pagevec_release(&pvec);
370 }
371 BUG_ON(!lstart && mapping->nrpages);
372 hugetlb_unreserve_pages(inode, start, freed);
373 }
374
375 static void hugetlbfs_delete_inode(struct inode *inode)
376 {
377 truncate_hugepages(inode, 0);
378 clear_inode(inode);
379 }
380
381 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
382 {
383 struct super_block *sb = inode->i_sb;
384
385 if (!hlist_unhashed(&inode->i_hash)) {
386 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
387 list_move(&inode->i_list, &inode_unused);
388 inodes_stat.nr_unused++;
389 if (!sb || (sb->s_flags & MS_ACTIVE)) {
390 spin_unlock(&inode_lock);
391 return;
392 }
393 inode->i_state |= I_WILL_FREE;
394 spin_unlock(&inode_lock);
395 /*
396 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
397 * in our backing_dev_info.
398 */
399 write_inode_now(inode, 1);
400 spin_lock(&inode_lock);
401 inode->i_state &= ~I_WILL_FREE;
402 inodes_stat.nr_unused--;
403 hlist_del_init(&inode->i_hash);
404 }
405 list_del_init(&inode->i_list);
406 list_del_init(&inode->i_sb_list);
407 inode->i_state |= I_FREEING;
408 inodes_stat.nr_inodes--;
409 spin_unlock(&inode_lock);
410 truncate_hugepages(inode, 0);
411 clear_inode(inode);
412 destroy_inode(inode);
413 }
414
415 static void hugetlbfs_drop_inode(struct inode *inode)
416 {
417 if (!inode->i_nlink)
418 generic_delete_inode(inode);
419 else
420 hugetlbfs_forget_inode(inode);
421 }
422
423 static inline void
424 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
425 {
426 struct vm_area_struct *vma;
427 struct prio_tree_iter iter;
428
429 vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
430 unsigned long v_offset;
431
432 /*
433 * Can the expression below overflow on 32-bit arches?
434 * No, because the prio_tree returns us only those vmas
435 * which overlap the truncated area starting at pgoff,
436 * and no vma on a 32-bit arch can span beyond the 4GB.
437 */
438 if (vma->vm_pgoff < pgoff)
439 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
440 else
441 v_offset = 0;
442
443 __unmap_hugepage_range(vma,
444 vma->vm_start + v_offset, vma->vm_end);
445 }
446 }
447
448 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
449 {
450 pgoff_t pgoff;
451 struct address_space *mapping = inode->i_mapping;
452
453 BUG_ON(offset & ~HPAGE_MASK);
454 pgoff = offset >> PAGE_SHIFT;
455
456 i_size_write(inode, offset);
457 spin_lock(&mapping->i_mmap_lock);
458 if (!prio_tree_empty(&mapping->i_mmap))
459 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
460 spin_unlock(&mapping->i_mmap_lock);
461 truncate_hugepages(inode, offset);
462 return 0;
463 }
464
465 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
466 {
467 struct inode *inode = dentry->d_inode;
468 int error;
469 unsigned int ia_valid = attr->ia_valid;
470
471 BUG_ON(!inode);
472
473 error = inode_change_ok(inode, attr);
474 if (error)
475 goto out;
476
477 if (ia_valid & ATTR_SIZE) {
478 error = -EINVAL;
479 if (!(attr->ia_size & ~HPAGE_MASK))
480 error = hugetlb_vmtruncate(inode, attr->ia_size);
481 if (error)
482 goto out;
483 attr->ia_valid &= ~ATTR_SIZE;
484 }
485 error = inode_setattr(inode, attr);
486 out:
487 return error;
488 }
489
490 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
491 gid_t gid, int mode, dev_t dev)
492 {
493 struct inode *inode;
494
495 inode = new_inode(sb);
496 if (inode) {
497 struct hugetlbfs_inode_info *info;
498 inode->i_mode = mode;
499 inode->i_uid = uid;
500 inode->i_gid = gid;
501 inode->i_blocks = 0;
502 inode->i_mapping->a_ops = &hugetlbfs_aops;
503 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
504 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
505 INIT_LIST_HEAD(&inode->i_mapping->private_list);
506 info = HUGETLBFS_I(inode);
507 mpol_shared_policy_init(&info->policy, NULL);
508 switch (mode & S_IFMT) {
509 default:
510 init_special_inode(inode, mode, dev);
511 break;
512 case S_IFREG:
513 inode->i_op = &hugetlbfs_inode_operations;
514 inode->i_fop = &hugetlbfs_file_operations;
515 break;
516 case S_IFDIR:
517 inode->i_op = &hugetlbfs_dir_inode_operations;
518 inode->i_fop = &simple_dir_operations;
519
520 /* directory inodes start off with i_nlink == 2 (for "." entry) */
521 inc_nlink(inode);
522 break;
523 case S_IFLNK:
524 inode->i_op = &page_symlink_inode_operations;
525 break;
526 }
527 }
528 return inode;
529 }
530
531 /*
532 * File creation. Allocate an inode, and we're done..
533 */
534 static int hugetlbfs_mknod(struct inode *dir,
535 struct dentry *dentry, int mode, dev_t dev)
536 {
537 struct inode *inode;
538 int error = -ENOSPC;
539 gid_t gid;
540
541 if (dir->i_mode & S_ISGID) {
542 gid = dir->i_gid;
543 if (S_ISDIR(mode))
544 mode |= S_ISGID;
545 } else {
546 gid = current->fsgid;
547 }
548 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
549 if (inode) {
550 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
551 d_instantiate(dentry, inode);
552 dget(dentry); /* Extra count - pin the dentry in core */
553 error = 0;
554 }
555 return error;
556 }
557
558 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
559 {
560 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
561 if (!retval)
562 inc_nlink(dir);
563 return retval;
564 }
565
566 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
567 {
568 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
569 }
570
571 static int hugetlbfs_symlink(struct inode *dir,
572 struct dentry *dentry, const char *symname)
573 {
574 struct inode *inode;
575 int error = -ENOSPC;
576 gid_t gid;
577
578 if (dir->i_mode & S_ISGID)
579 gid = dir->i_gid;
580 else
581 gid = current->fsgid;
582
583 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
584 gid, S_IFLNK|S_IRWXUGO, 0);
585 if (inode) {
586 int l = strlen(symname)+1;
587 error = page_symlink(inode, symname, l);
588 if (!error) {
589 d_instantiate(dentry, inode);
590 dget(dentry);
591 } else
592 iput(inode);
593 }
594 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
595
596 return error;
597 }
598
599 /*
600 * mark the head page dirty
601 */
602 static int hugetlbfs_set_page_dirty(struct page *page)
603 {
604 struct page *head = compound_head(page);
605
606 SetPageDirty(head);
607 return 0;
608 }
609
610 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
611 {
612 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
613
614 buf->f_type = HUGETLBFS_MAGIC;
615 buf->f_bsize = HPAGE_SIZE;
616 if (sbinfo) {
617 spin_lock(&sbinfo->stat_lock);
618 /* If no limits set, just report 0 for max/free/used
619 * blocks, like simple_statfs() */
620 if (sbinfo->max_blocks >= 0) {
621 buf->f_blocks = sbinfo->max_blocks;
622 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
623 buf->f_files = sbinfo->max_inodes;
624 buf->f_ffree = sbinfo->free_inodes;
625 }
626 spin_unlock(&sbinfo->stat_lock);
627 }
628 buf->f_namelen = NAME_MAX;
629 return 0;
630 }
631
632 static void hugetlbfs_put_super(struct super_block *sb)
633 {
634 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
635
636 if (sbi) {
637 sb->s_fs_info = NULL;
638 kfree(sbi);
639 }
640 }
641
642 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
643 {
644 if (sbinfo->free_inodes >= 0) {
645 spin_lock(&sbinfo->stat_lock);
646 if (unlikely(!sbinfo->free_inodes)) {
647 spin_unlock(&sbinfo->stat_lock);
648 return 0;
649 }
650 sbinfo->free_inodes--;
651 spin_unlock(&sbinfo->stat_lock);
652 }
653
654 return 1;
655 }
656
657 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
658 {
659 if (sbinfo->free_inodes >= 0) {
660 spin_lock(&sbinfo->stat_lock);
661 sbinfo->free_inodes++;
662 spin_unlock(&sbinfo->stat_lock);
663 }
664 }
665
666
667 static struct kmem_cache *hugetlbfs_inode_cachep;
668
669 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
670 {
671 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
672 struct hugetlbfs_inode_info *p;
673
674 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
675 return NULL;
676 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
677 if (unlikely(!p)) {
678 hugetlbfs_inc_free_inodes(sbinfo);
679 return NULL;
680 }
681 return &p->vfs_inode;
682 }
683
684 static void hugetlbfs_destroy_inode(struct inode *inode)
685 {
686 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
687 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
688 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
689 }
690
691 static const struct address_space_operations hugetlbfs_aops = {
692 .readpage = hugetlbfs_readpage,
693 .write_begin = hugetlbfs_write_begin,
694 .write_end = hugetlbfs_write_end,
695 .set_page_dirty = hugetlbfs_set_page_dirty,
696 };
697
698
699 static void init_once(struct kmem_cache *cachep, void *foo)
700 {
701 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
702
703 inode_init_once(&ei->vfs_inode);
704 }
705
706 const struct file_operations hugetlbfs_file_operations = {
707 .read = hugetlbfs_read,
708 .mmap = hugetlbfs_file_mmap,
709 .fsync = simple_sync_file,
710 .get_unmapped_area = hugetlb_get_unmapped_area,
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 .statfs = hugetlbfs_statfs,
734 .delete_inode = hugetlbfs_delete_inode,
735 .drop_inode = hugetlbfs_drop_inode,
736 .put_super = hugetlbfs_put_super,
737 .show_options = generic_show_options,
738 };
739
740 static int
741 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
742 {
743 char *p, *rest;
744 substring_t args[MAX_OPT_ARGS];
745 int option;
746
747 if (!options)
748 return 0;
749
750 while ((p = strsep(&options, ",")) != NULL) {
751 int token;
752 if (!*p)
753 continue;
754
755 token = match_token(p, tokens, args);
756 switch (token) {
757 case Opt_uid:
758 if (match_int(&args[0], &option))
759 goto bad_val;
760 pconfig->uid = option;
761 break;
762
763 case Opt_gid:
764 if (match_int(&args[0], &option))
765 goto bad_val;
766 pconfig->gid = option;
767 break;
768
769 case Opt_mode:
770 if (match_octal(&args[0], &option))
771 goto bad_val;
772 pconfig->mode = option & 01777U;
773 break;
774
775 case Opt_size: {
776 unsigned long long 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 if (*rest == '%') {
782 size <<= HPAGE_SHIFT;
783 size *= max_huge_pages;
784 do_div(size, 100);
785 }
786 pconfig->nr_blocks = (size >> HPAGE_SHIFT);
787 break;
788 }
789
790 case Opt_nr_inodes:
791 /* memparse() will accept a K/M/G without a digit */
792 if (!isdigit(*args[0].from))
793 goto bad_val;
794 pconfig->nr_inodes = memparse(args[0].from, &rest);
795 break;
796
797 default:
798 printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
799 p);
800 return -EINVAL;
801 break;
802 }
803 }
804 return 0;
805
806 bad_val:
807 printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
808 args[0].from, p);
809 return 1;
810 }
811
812 static int
813 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
814 {
815 struct inode * inode;
816 struct dentry * root;
817 int ret;
818 struct hugetlbfs_config config;
819 struct hugetlbfs_sb_info *sbinfo;
820
821 save_mount_options(sb, data);
822
823 config.nr_blocks = -1; /* No limit on size by default */
824 config.nr_inodes = -1; /* No limit on number of inodes by default */
825 config.uid = current->fsuid;
826 config.gid = current->fsgid;
827 config.mode = 0755;
828 ret = hugetlbfs_parse_options(data, &config);
829 if (ret)
830 return ret;
831
832 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
833 if (!sbinfo)
834 return -ENOMEM;
835 sb->s_fs_info = sbinfo;
836 spin_lock_init(&sbinfo->stat_lock);
837 sbinfo->max_blocks = config.nr_blocks;
838 sbinfo->free_blocks = config.nr_blocks;
839 sbinfo->max_inodes = config.nr_inodes;
840 sbinfo->free_inodes = config.nr_inodes;
841 sb->s_maxbytes = MAX_LFS_FILESIZE;
842 sb->s_blocksize = HPAGE_SIZE;
843 sb->s_blocksize_bits = HPAGE_SHIFT;
844 sb->s_magic = HUGETLBFS_MAGIC;
845 sb->s_op = &hugetlbfs_ops;
846 sb->s_time_gran = 1;
847 inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
848 S_IFDIR | config.mode, 0);
849 if (!inode)
850 goto out_free;
851
852 root = d_alloc_root(inode);
853 if (!root) {
854 iput(inode);
855 goto out_free;
856 }
857 sb->s_root = root;
858 return 0;
859 out_free:
860 kfree(sbinfo);
861 return -ENOMEM;
862 }
863
864 int hugetlb_get_quota(struct address_space *mapping, long delta)
865 {
866 int ret = 0;
867 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
868
869 if (sbinfo->free_blocks > -1) {
870 spin_lock(&sbinfo->stat_lock);
871 if (sbinfo->free_blocks - delta >= 0)
872 sbinfo->free_blocks -= delta;
873 else
874 ret = -ENOMEM;
875 spin_unlock(&sbinfo->stat_lock);
876 }
877
878 return ret;
879 }
880
881 void hugetlb_put_quota(struct address_space *mapping, long delta)
882 {
883 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
884
885 if (sbinfo->free_blocks > -1) {
886 spin_lock(&sbinfo->stat_lock);
887 sbinfo->free_blocks += delta;
888 spin_unlock(&sbinfo->stat_lock);
889 }
890 }
891
892 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
893 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
894 {
895 return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
896 }
897
898 static struct file_system_type hugetlbfs_fs_type = {
899 .name = "hugetlbfs",
900 .get_sb = hugetlbfs_get_sb,
901 .kill_sb = kill_litter_super,
902 };
903
904 static struct vfsmount *hugetlbfs_vfsmount;
905
906 static int can_do_hugetlb_shm(void)
907 {
908 return likely(capable(CAP_IPC_LOCK) ||
909 in_group_p(sysctl_hugetlb_shm_group) ||
910 can_do_mlock());
911 }
912
913 struct file *hugetlb_file_setup(const char *name, size_t size)
914 {
915 int error = -ENOMEM;
916 struct file *file;
917 struct inode *inode;
918 struct dentry *dentry, *root;
919 struct qstr quick_string;
920
921 if (!hugetlbfs_vfsmount)
922 return ERR_PTR(-ENOENT);
923
924 if (!can_do_hugetlb_shm())
925 return ERR_PTR(-EPERM);
926
927 if (!user_shm_lock(size, current->user))
928 return ERR_PTR(-ENOMEM);
929
930 root = hugetlbfs_vfsmount->mnt_root;
931 quick_string.name = name;
932 quick_string.len = strlen(quick_string.name);
933 quick_string.hash = 0;
934 dentry = d_alloc(root, &quick_string);
935 if (!dentry)
936 goto out_shm_unlock;
937
938 error = -ENOSPC;
939 inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
940 current->fsgid, S_IFREG | S_IRWXUGO, 0);
941 if (!inode)
942 goto out_dentry;
943
944 error = -ENOMEM;
945 if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT, NULL))
946 goto out_inode;
947
948 d_instantiate(dentry, inode);
949 inode->i_size = size;
950 inode->i_nlink = 0;
951
952 error = -ENFILE;
953 file = alloc_file(hugetlbfs_vfsmount, dentry,
954 FMODE_WRITE | FMODE_READ,
955 &hugetlbfs_file_operations);
956 if (!file)
957 goto out_dentry; /* inode is already attached */
958
959 return file;
960
961 out_inode:
962 iput(inode);
963 out_dentry:
964 dput(dentry);
965 out_shm_unlock:
966 user_shm_unlock(size, current->user);
967 return ERR_PTR(error);
968 }
969
970 static int __init init_hugetlbfs_fs(void)
971 {
972 int error;
973 struct vfsmount *vfsmount;
974
975 error = bdi_init(&hugetlbfs_backing_dev_info);
976 if (error)
977 return error;
978
979 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
980 sizeof(struct hugetlbfs_inode_info),
981 0, 0, init_once);
982 if (hugetlbfs_inode_cachep == NULL)
983 goto out2;
984
985 error = register_filesystem(&hugetlbfs_fs_type);
986 if (error)
987 goto out;
988
989 vfsmount = kern_mount(&hugetlbfs_fs_type);
990
991 if (!IS_ERR(vfsmount)) {
992 hugetlbfs_vfsmount = vfsmount;
993 return 0;
994 }
995
996 error = PTR_ERR(vfsmount);
997
998 out:
999 if (error)
1000 kmem_cache_destroy(hugetlbfs_inode_cachep);
1001 out2:
1002 bdi_destroy(&hugetlbfs_backing_dev_info);
1003 return error;
1004 }
1005
1006 static void __exit exit_hugetlbfs_fs(void)
1007 {
1008 kmem_cache_destroy(hugetlbfs_inode_cachep);
1009 unregister_filesystem(&hugetlbfs_fs_type);
1010 bdi_destroy(&hugetlbfs_backing_dev_info);
1011 }
1012
1013 module_init(init_hugetlbfs_fs)
1014 module_exit(exit_hugetlbfs_fs)
1015
1016 MODULE_LICENSE("GPL");
Support for the Chinese Samsung S3C2440 based development boards