hugetlbfs: check for pgoff value overflow
[pandora-kernel.git] / fs / hugetlbfs / inode.c
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 /*
80  * Mask used when checking the page offset value passed in via system
81  * calls.  This value will be converted to a loff_t which is signed.
82  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
83  * value.  The extra bit (- 1 in the shift value) is to take the sign
84  * bit into account.
85  */
86 #define PGOFF_LOFFT_MAX \
87         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
88
89 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
90 {
91         struct inode *inode = file->f_path.dentry->d_inode;
92         loff_t len, vma_len;
93         int ret;
94         struct hstate *h = hstate_file(file);
95
96         /*
97          * vma address alignment (but not the pgoff alignment) has
98          * already been checked by prepare_hugepage_range.  If you add
99          * any error returns here, do so after setting VM_HUGETLB, so
100          * is_vm_hugetlb_page tests below unmap_region go the right
101          * way when do_mmap_pgoff unwinds (may be important on powerpc
102          * and ia64).
103          */
104         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
105         vma->vm_ops = &hugetlb_vm_ops;
106
107         /*
108          * page based offset in vm_pgoff could be sufficiently large to
109          * overflow a (l)off_t when converted to byte offset.
110          */
111         if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
112                 return -EINVAL;
113
114         /* must be huge page aligned */
115         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
116                 return -EINVAL;
117
118         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
119         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
120         /* check for overflow */
121         if (len < vma_len)
122                 return -EINVAL;
123
124         mutex_lock(&inode->i_mutex);
125         file_accessed(file);
126
127         ret = -ENOMEM;
128         if (hugetlb_reserve_pages(inode,
129                                 vma->vm_pgoff >> huge_page_order(h),
130                                 len >> huge_page_shift(h), vma,
131                                 vma->vm_flags))
132                 goto out;
133
134         ret = 0;
135         hugetlb_prefault_arch_hook(vma->vm_mm);
136         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
137                 i_size_write(inode, len);
138 out:
139         mutex_unlock(&inode->i_mutex);
140
141         return ret;
142 }
143
144 /*
145  * Called under down_write(mmap_sem).
146  */
147
148 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
149 static unsigned long
150 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
151                 unsigned long len, unsigned long pgoff, unsigned long flags)
152 {
153         struct mm_struct *mm = current->mm;
154         struct vm_area_struct *vma;
155         unsigned long start_addr;
156         struct hstate *h = hstate_file(file);
157
158         if (len & ~huge_page_mask(h))
159                 return -EINVAL;
160         if (len > TASK_SIZE)
161                 return -ENOMEM;
162
163         if (flags & MAP_FIXED) {
164                 if (prepare_hugepage_range(file, addr, len))
165                         return -EINVAL;
166                 return addr;
167         }
168
169         if (addr) {
170                 addr = ALIGN(addr, huge_page_size(h));
171                 vma = find_vma(mm, addr);
172                 if (TASK_SIZE - len >= addr &&
173                     (!vma || addr + len <= vm_start_gap(vma)))
174                         return addr;
175         }
176
177         start_addr = mm->free_area_cache;
178
179         if (len <= mm->cached_hole_size)
180                 start_addr = TASK_UNMAPPED_BASE;
181
182 full_search:
183         addr = ALIGN(start_addr, huge_page_size(h));
184
185         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
186                 /* At this point:  (!vma || addr < vma->vm_end). */
187                 if (TASK_SIZE - len < addr) {
188                         /*
189                          * Start a new search - just in case we missed
190                          * some holes.
191                          */
192                         if (start_addr != TASK_UNMAPPED_BASE) {
193                                 start_addr = TASK_UNMAPPED_BASE;
194                                 goto full_search;
195                         }
196                         return -ENOMEM;
197                 }
198
199                 if (!vma || addr + len <= vm_start_gap(vma))
200                         return addr;
201                 addr = ALIGN(vma->vm_end, huge_page_size(h));
202         }
203 }
204 #endif
205
206 static int
207 hugetlbfs_read_actor(struct page *page, unsigned long offset,
208                         char __user *buf, unsigned long count,
209                         unsigned long size)
210 {
211         char *kaddr;
212         unsigned long left, copied = 0;
213         int i, chunksize;
214
215         if (size > count)
216                 size = count;
217
218         /* Find which 4k chunk and offset with in that chunk */
219         i = offset >> PAGE_CACHE_SHIFT;
220         offset = offset & ~PAGE_CACHE_MASK;
221
222         while (size) {
223                 chunksize = PAGE_CACHE_SIZE;
224                 if (offset)
225                         chunksize -= offset;
226                 if (chunksize > size)
227                         chunksize = size;
228                 kaddr = kmap(&page[i]);
229                 left = __copy_to_user(buf, kaddr + offset, chunksize);
230                 kunmap(&page[i]);
231                 if (left) {
232                         copied += (chunksize - left);
233                         break;
234                 }
235                 offset = 0;
236                 size -= chunksize;
237                 buf += chunksize;
238                 copied += chunksize;
239                 i++;
240         }
241         return copied ? copied : -EFAULT;
242 }
243
244 /*
245  * Support for read() - Find the page attached to f_mapping and copy out the
246  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
247  * since it has PAGE_CACHE_SIZE assumptions.
248  */
249 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
250                               size_t len, loff_t *ppos)
251 {
252         struct hstate *h = hstate_file(filp);
253         struct address_space *mapping = filp->f_mapping;
254         struct inode *inode = mapping->host;
255         unsigned long index = *ppos >> huge_page_shift(h);
256         unsigned long offset = *ppos & ~huge_page_mask(h);
257         unsigned long end_index;
258         loff_t isize;
259         ssize_t retval = 0;
260
261         /* validate length */
262         if (len == 0)
263                 goto out;
264
265         for (;;) {
266                 struct page *page;
267                 unsigned long nr, ret;
268                 int ra;
269
270                 /* nr is the maximum number of bytes to copy from this page */
271                 nr = huge_page_size(h);
272                 isize = i_size_read(inode);
273                 if (!isize)
274                         goto out;
275                 end_index = (isize - 1) >> huge_page_shift(h);
276                 if (index >= end_index) {
277                         if (index > end_index)
278                                 goto out;
279                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
280                         if (nr <= offset)
281                                 goto out;
282                 }
283                 nr = nr - offset;
284
285                 /* Find the page */
286                 page = find_lock_page(mapping, index);
287                 if (unlikely(page == NULL)) {
288                         /*
289                          * We have a HOLE, zero out the user-buffer for the
290                          * length of the hole or request.
291                          */
292                         ret = len < nr ? len : nr;
293                         if (clear_user(buf, ret))
294                                 ra = -EFAULT;
295                         else
296                                 ra = 0;
297                 } else {
298                         unlock_page(page);
299
300                         /*
301                          * We have the page, copy it to user space buffer.
302                          */
303                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
304                         ret = ra;
305                         page_cache_release(page);
306                 }
307                 if (ra < 0) {
308                         if (retval == 0)
309                                 retval = ra;
310                         goto out;
311                 }
312
313                 offset += ret;
314                 retval += ret;
315                 len -= ret;
316                 index += offset >> huge_page_shift(h);
317                 offset &= ~huge_page_mask(h);
318
319                 /* short read or no more work */
320                 if ((ret != nr) || (len == 0))
321                         break;
322         }
323 out:
324         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
325         return retval;
326 }
327
328 static int hugetlbfs_write_begin(struct file *file,
329                         struct address_space *mapping,
330                         loff_t pos, unsigned len, unsigned flags,
331                         struct page **pagep, void **fsdata)
332 {
333         return -EINVAL;
334 }
335
336 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
337                         loff_t pos, unsigned len, unsigned copied,
338                         struct page *page, void *fsdata)
339 {
340         BUG();
341         return -EINVAL;
342 }
343
344 static void truncate_huge_page(struct page *page)
345 {
346         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
347         ClearPageUptodate(page);
348         delete_from_page_cache(page);
349 }
350
351 static void truncate_hugepages(struct inode *inode, loff_t lstart)
352 {
353         struct hstate *h = hstate_inode(inode);
354         struct address_space *mapping = &inode->i_data;
355         const pgoff_t start = lstart >> huge_page_shift(h);
356         struct pagevec pvec;
357         pgoff_t next;
358         int i, freed = 0;
359
360         pagevec_init(&pvec, 0);
361         next = start;
362         while (1) {
363                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
364                         if (next == start)
365                                 break;
366                         next = start;
367                         continue;
368                 }
369
370                 for (i = 0; i < pagevec_count(&pvec); ++i) {
371                         struct page *page = pvec.pages[i];
372
373                         lock_page(page);
374                         if (page->index > next)
375                                 next = page->index;
376                         ++next;
377                         truncate_huge_page(page);
378                         unlock_page(page);
379                         freed++;
380                 }
381                 huge_pagevec_release(&pvec);
382         }
383         BUG_ON(!lstart && mapping->nrpages);
384         hugetlb_unreserve_pages(inode, start, freed);
385 }
386
387 static void hugetlbfs_evict_inode(struct inode *inode)
388 {
389         truncate_hugepages(inode, 0);
390         end_writeback(inode);
391 }
392
393 static inline void
394 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
395 {
396         struct vm_area_struct *vma;
397         struct prio_tree_iter iter;
398
399         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
400                 unsigned long v_offset;
401
402                 /*
403                  * Can the expression below overflow on 32-bit arches?
404                  * No, because the prio_tree returns us only those vmas
405                  * which overlap the truncated area starting at pgoff,
406                  * and no vma on a 32-bit arch can span beyond the 4GB.
407                  */
408                 if (vma->vm_pgoff < pgoff)
409                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
410                 else
411                         v_offset = 0;
412
413                 __unmap_hugepage_range(vma,
414                                 vma->vm_start + v_offset, vma->vm_end, NULL);
415         }
416 }
417
418 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
419 {
420         pgoff_t pgoff;
421         struct address_space *mapping = inode->i_mapping;
422         struct hstate *h = hstate_inode(inode);
423
424         BUG_ON(offset & ~huge_page_mask(h));
425         pgoff = offset >> PAGE_SHIFT;
426
427         i_size_write(inode, offset);
428         mutex_lock(&mapping->i_mmap_mutex);
429         if (!prio_tree_empty(&mapping->i_mmap))
430                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
431         mutex_unlock(&mapping->i_mmap_mutex);
432         truncate_hugepages(inode, offset);
433         return 0;
434 }
435
436 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
437 {
438         struct inode *inode = dentry->d_inode;
439         struct hstate *h = hstate_inode(inode);
440         int error;
441         unsigned int ia_valid = attr->ia_valid;
442
443         BUG_ON(!inode);
444
445         error = setattr_prepare(dentry, attr);
446         if (error)
447                 return error;
448
449         if (ia_valid & ATTR_SIZE) {
450                 error = -EINVAL;
451                 if (attr->ia_size & ~huge_page_mask(h))
452                         return -EINVAL;
453                 error = hugetlb_vmtruncate(inode, attr->ia_size);
454                 if (error)
455                         return error;
456         }
457
458         setattr_copy(inode, attr);
459         mark_inode_dirty(inode);
460         return 0;
461 }
462
463 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
464                                         gid_t gid, int mode, dev_t dev)
465 {
466         struct inode *inode;
467
468         inode = new_inode(sb);
469         if (inode) {
470                 struct hugetlbfs_inode_info *info;
471                 inode->i_ino = get_next_ino();
472                 inode->i_mode = mode;
473                 inode->i_uid = uid;
474                 inode->i_gid = gid;
475                 inode->i_mapping->a_ops = &hugetlbfs_aops;
476                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
477                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
478                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
479                 info = HUGETLBFS_I(inode);
480                 /*
481                  * The policy is initialized here even if we are creating a
482                  * private inode because initialization simply creates an
483                  * an empty rb tree and calls spin_lock_init(), later when we
484                  * call mpol_free_shared_policy() it will just return because
485                  * the rb tree will still be empty.
486                  */
487                 mpol_shared_policy_init(&info->policy, NULL);
488                 switch (mode & S_IFMT) {
489                 default:
490                         init_special_inode(inode, mode, dev);
491                         break;
492                 case S_IFREG:
493                         inode->i_op = &hugetlbfs_inode_operations;
494                         inode->i_fop = &hugetlbfs_file_operations;
495                         break;
496                 case S_IFDIR:
497                         inode->i_op = &hugetlbfs_dir_inode_operations;
498                         inode->i_fop = &simple_dir_operations;
499
500                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
501                         inc_nlink(inode);
502                         break;
503                 case S_IFLNK:
504                         inode->i_op = &page_symlink_inode_operations;
505                         break;
506                 }
507                 lockdep_annotate_inode_mutex_key(inode);
508         }
509         return inode;
510 }
511
512 /*
513  * File creation. Allocate an inode, and we're done..
514  */
515 static int hugetlbfs_mknod(struct inode *dir,
516                         struct dentry *dentry, int mode, dev_t dev)
517 {
518         struct inode *inode;
519         int error = -ENOSPC;
520         gid_t gid;
521
522         if (dir->i_mode & S_ISGID) {
523                 gid = dir->i_gid;
524                 if (S_ISDIR(mode))
525                         mode |= S_ISGID;
526         } else {
527                 gid = current_fsgid();
528         }
529         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
530         if (inode) {
531                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
532                 d_instantiate(dentry, inode);
533                 dget(dentry);   /* Extra count - pin the dentry in core */
534                 error = 0;
535         }
536         return error;
537 }
538
539 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
540 {
541         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
542         if (!retval)
543                 inc_nlink(dir);
544         return retval;
545 }
546
547 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
548 {
549         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
550 }
551
552 static int hugetlbfs_symlink(struct inode *dir,
553                         struct dentry *dentry, const char *symname)
554 {
555         struct inode *inode;
556         int error = -ENOSPC;
557         gid_t gid;
558
559         if (dir->i_mode & S_ISGID)
560                 gid = dir->i_gid;
561         else
562                 gid = current_fsgid();
563
564         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
565                                         gid, S_IFLNK|S_IRWXUGO, 0);
566         if (inode) {
567                 int l = strlen(symname)+1;
568                 error = page_symlink(inode, symname, l);
569                 if (!error) {
570                         d_instantiate(dentry, inode);
571                         dget(dentry);
572                 } else
573                         iput(inode);
574         }
575         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
576
577         return error;
578 }
579
580 /*
581  * mark the head page dirty
582  */
583 static int hugetlbfs_set_page_dirty(struct page *page)
584 {
585         struct page *head = compound_head(page);
586
587         SetPageDirty(head);
588         return 0;
589 }
590
591 static int hugetlbfs_migrate_page(struct address_space *mapping,
592                                 struct page *newpage, struct page *page,
593                                 enum migrate_mode mode)
594 {
595         int rc;
596
597         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
598         if (rc)
599                 return rc;
600         migrate_page_copy(newpage, page);
601
602         return 0;
603 }
604
605 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
606 {
607         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
608         struct hstate *h = hstate_inode(dentry->d_inode);
609
610         buf->f_type = HUGETLBFS_MAGIC;
611         buf->f_bsize = huge_page_size(h);
612         if (sbinfo) {
613                 spin_lock(&sbinfo->stat_lock);
614                 /* If no limits set, just report 0 for max/free/used
615                  * blocks, like simple_statfs() */
616                 if (sbinfo->spool) {
617                         long free_pages;
618
619                         spin_lock(&sbinfo->spool->lock);
620                         buf->f_blocks = sbinfo->spool->max_hpages;
621                         free_pages = sbinfo->spool->max_hpages
622                                 - sbinfo->spool->used_hpages;
623                         buf->f_bavail = buf->f_bfree = free_pages;
624                         spin_unlock(&sbinfo->spool->lock);
625                         buf->f_files = sbinfo->max_inodes;
626                         buf->f_ffree = sbinfo->free_inodes;
627                 }
628                 spin_unlock(&sbinfo->stat_lock);
629         }
630         buf->f_namelen = NAME_MAX;
631         return 0;
632 }
633
634 static void hugetlbfs_put_super(struct super_block *sb)
635 {
636         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
637
638         if (sbi) {
639                 sb->s_fs_info = NULL;
640
641                 if (sbi->spool)
642                         hugepage_put_subpool(sbi->spool);
643
644                 kfree(sbi);
645         }
646 }
647
648 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
649 {
650         if (sbinfo->free_inodes >= 0) {
651                 spin_lock(&sbinfo->stat_lock);
652                 if (unlikely(!sbinfo->free_inodes)) {
653                         spin_unlock(&sbinfo->stat_lock);
654                         return 0;
655                 }
656                 sbinfo->free_inodes--;
657                 spin_unlock(&sbinfo->stat_lock);
658         }
659
660         return 1;
661 }
662
663 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
664 {
665         if (sbinfo->free_inodes >= 0) {
666                 spin_lock(&sbinfo->stat_lock);
667                 sbinfo->free_inodes++;
668                 spin_unlock(&sbinfo->stat_lock);
669         }
670 }
671
672
673 static struct kmem_cache *hugetlbfs_inode_cachep;
674
675 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
676 {
677         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
678         struct hugetlbfs_inode_info *p;
679
680         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
681                 return NULL;
682         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
683         if (unlikely(!p)) {
684                 hugetlbfs_inc_free_inodes(sbinfo);
685                 return NULL;
686         }
687         return &p->vfs_inode;
688 }
689
690 static void hugetlbfs_i_callback(struct rcu_head *head)
691 {
692         struct inode *inode = container_of(head, struct inode, i_rcu);
693         INIT_LIST_HEAD(&inode->i_dentry);
694         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(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         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
702 }
703
704 static const struct address_space_operations hugetlbfs_aops = {
705         .write_begin    = hugetlbfs_write_begin,
706         .write_end      = hugetlbfs_write_end,
707         .set_page_dirty = hugetlbfs_set_page_dirty,
708         .migratepage    = hugetlbfs_migrate_page,
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                  = noop_fsync,
723         .get_unmapped_area      = hugetlb_get_unmapped_area,
724         .llseek         = default_llseek,
725 };
726
727 static const struct inode_operations hugetlbfs_dir_inode_operations = {
728         .create         = hugetlbfs_create,
729         .lookup         = simple_lookup,
730         .link           = simple_link,
731         .unlink         = simple_unlink,
732         .symlink        = hugetlbfs_symlink,
733         .mkdir          = hugetlbfs_mkdir,
734         .rmdir          = simple_rmdir,
735         .mknod          = hugetlbfs_mknod,
736         .rename         = simple_rename,
737         .setattr        = hugetlbfs_setattr,
738 };
739
740 static const struct inode_operations hugetlbfs_inode_operations = {
741         .setattr        = hugetlbfs_setattr,
742 };
743
744 static const struct super_operations hugetlbfs_ops = {
745         .alloc_inode    = hugetlbfs_alloc_inode,
746         .destroy_inode  = hugetlbfs_destroy_inode,
747         .evict_inode    = hugetlbfs_evict_inode,
748         .statfs         = hugetlbfs_statfs,
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 -EINVAL;
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_inodes = config.nr_inodes;
876         sbinfo->free_inodes = config.nr_inodes;
877         sbinfo->spool = NULL;
878         if (config.nr_blocks != -1) {
879                 sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
880                 if (!sbinfo->spool)
881                         goto out_free;
882         }
883         sb->s_maxbytes = MAX_LFS_FILESIZE;
884         sb->s_blocksize = huge_page_size(config.hstate);
885         sb->s_blocksize_bits = huge_page_shift(config.hstate);
886         sb->s_magic = HUGETLBFS_MAGIC;
887         sb->s_op = &hugetlbfs_ops;
888         sb->s_time_gran = 1;
889         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
890                                         S_IFDIR | config.mode, 0);
891         if (!inode)
892                 goto out_free;
893
894         root = d_alloc_root(inode);
895         if (!root) {
896                 iput(inode);
897                 goto out_free;
898         }
899         sb->s_root = root;
900         return 0;
901 out_free:
902         if (sbinfo->spool)
903                 kfree(sbinfo->spool);
904         kfree(sbinfo);
905         return -ENOMEM;
906 }
907
908 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
909         int flags, const char *dev_name, void *data)
910 {
911         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
912 }
913
914 static struct file_system_type hugetlbfs_fs_type = {
915         .name           = "hugetlbfs",
916         .mount          = hugetlbfs_mount,
917         .kill_sb        = kill_litter_super,
918 };
919
920 static struct vfsmount *hugetlbfs_vfsmount;
921
922 static int can_do_hugetlb_shm(void)
923 {
924         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
925 }
926
927 struct file *hugetlb_file_setup(const char *name, size_t size,
928                                 vm_flags_t acctflag,
929                                 struct user_struct **user, int creat_flags)
930 {
931         int error = -ENOMEM;
932         struct file *file;
933         struct inode *inode;
934         struct path path;
935         struct dentry *root;
936         struct qstr quick_string;
937
938         *user = NULL;
939         if (!hugetlbfs_vfsmount)
940                 return ERR_PTR(-ENOENT);
941
942         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
943                 *user = current_user();
944                 if (user_shm_lock(size, *user)) {
945                         printk_once(KERN_WARNING "Using mlock ulimits for SHM_HUGETLB is deprecated\n");
946                 } else {
947                         *user = NULL;
948                         return ERR_PTR(-EPERM);
949                 }
950         }
951
952         root = hugetlbfs_vfsmount->mnt_root;
953         quick_string.name = name;
954         quick_string.len = strlen(quick_string.name);
955         quick_string.hash = 0;
956         path.dentry = d_alloc(root, &quick_string);
957         if (!path.dentry)
958                 goto out_shm_unlock;
959
960         path.mnt = mntget(hugetlbfs_vfsmount);
961         error = -ENOSPC;
962         inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
963                                 current_fsgid(), S_IFREG | S_IRWXUGO, 0);
964         if (!inode)
965                 goto out_dentry;
966
967         error = -ENOMEM;
968         if (hugetlb_reserve_pages(inode, 0,
969                         size >> huge_page_shift(hstate_inode(inode)), NULL,
970                         acctflag))
971                 goto out_inode;
972
973         d_instantiate(path.dentry, inode);
974         inode->i_size = size;
975         clear_nlink(inode);
976
977         error = -ENFILE;
978         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
979                         &hugetlbfs_file_operations);
980         if (!file)
981                 goto out_dentry; /* inode is already attached */
982
983         return file;
984
985 out_inode:
986         iput(inode);
987 out_dentry:
988         path_put(&path);
989 out_shm_unlock:
990         if (*user) {
991                 user_shm_unlock(size, *user);
992                 *user = NULL;
993         }
994         return ERR_PTR(error);
995 }
996
997 static int __init init_hugetlbfs_fs(void)
998 {
999         int error;
1000         struct vfsmount *vfsmount;
1001
1002         if (!hugepages_supported()) {
1003                 pr_info("hugetlbfs: disabling because there are no supported hugepage sizes\n");
1004                 return -ENOTSUPP;
1005         }
1006
1007         error = bdi_init(&hugetlbfs_backing_dev_info);
1008         if (error)
1009                 return error;
1010
1011         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1012                                         sizeof(struct hugetlbfs_inode_info),
1013                                         0, 0, init_once);
1014         if (hugetlbfs_inode_cachep == NULL)
1015                 goto out2;
1016
1017         error = register_filesystem(&hugetlbfs_fs_type);
1018         if (error)
1019                 goto out;
1020
1021         vfsmount = kern_mount(&hugetlbfs_fs_type);
1022
1023         if (!IS_ERR(vfsmount)) {
1024                 hugetlbfs_vfsmount = vfsmount;
1025                 return 0;
1026         }
1027
1028         error = PTR_ERR(vfsmount);
1029
1030  out:
1031         if (error)
1032                 kmem_cache_destroy(hugetlbfs_inode_cachep);
1033  out2:
1034         bdi_destroy(&hugetlbfs_backing_dev_info);
1035         return error;
1036 }
1037
1038 static void __exit exit_hugetlbfs_fs(void)
1039 {
1040         kmem_cache_destroy(hugetlbfs_inode_cachep);
1041         kern_unmount(hugetlbfs_vfsmount);
1042         unregister_filesystem(&hugetlbfs_fs_type);
1043         bdi_destroy(&hugetlbfs_backing_dev_info);
1044 }
1045
1046 module_init(init_hugetlbfs_fs)
1047 module_exit(exit_hugetlbfs_fs)
1048
1049 MODULE_LICENSE("GPL");