filesystems: add missing nlink wrappers
[linux-3.10.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 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
80 {
81         struct inode *inode = file->f_path.dentry->d_inode;
82         loff_t len, vma_len;
83         int ret;
84         struct hstate *h = hstate_file(file);
85
86         /*
87          * vma address alignment (but not the pgoff alignment) has
88          * already been checked by prepare_hugepage_range.  If you add
89          * any error returns here, do so after setting VM_HUGETLB, so
90          * is_vm_hugetlb_page tests below unmap_region go the right
91          * way when do_mmap_pgoff unwinds (may be important on powerpc
92          * and ia64).
93          */
94         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
95         vma->vm_ops = &hugetlb_vm_ops;
96
97         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
98                 return -EINVAL;
99
100         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
101
102         mutex_lock(&inode->i_mutex);
103         file_accessed(file);
104
105         ret = -ENOMEM;
106         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
107
108         if (hugetlb_reserve_pages(inode,
109                                 vma->vm_pgoff >> huge_page_order(h),
110                                 len >> huge_page_shift(h), vma,
111                                 vma->vm_flags))
112                 goto out;
113
114         ret = 0;
115         hugetlb_prefault_arch_hook(vma->vm_mm);
116         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
117                 inode->i_size = len;
118 out:
119         mutex_unlock(&inode->i_mutex);
120
121         return ret;
122 }
123
124 /*
125  * Called under down_write(mmap_sem).
126  */
127
128 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
129 static unsigned long
130 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
131                 unsigned long len, unsigned long pgoff, unsigned long flags)
132 {
133         struct mm_struct *mm = current->mm;
134         struct vm_area_struct *vma;
135         unsigned long start_addr;
136         struct hstate *h = hstate_file(file);
137
138         if (len & ~huge_page_mask(h))
139                 return -EINVAL;
140         if (len > TASK_SIZE)
141                 return -ENOMEM;
142
143         if (flags & MAP_FIXED) {
144                 if (prepare_hugepage_range(file, addr, len))
145                         return -EINVAL;
146                 return addr;
147         }
148
149         if (addr) {
150                 addr = ALIGN(addr, huge_page_size(h));
151                 vma = find_vma(mm, addr);
152                 if (TASK_SIZE - len >= addr &&
153                     (!vma || addr + len <= vma->vm_start))
154                         return addr;
155         }
156
157         start_addr = mm->free_area_cache;
158
159         if (len <= mm->cached_hole_size)
160                 start_addr = TASK_UNMAPPED_BASE;
161
162 full_search:
163         addr = ALIGN(start_addr, huge_page_size(h));
164
165         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
166                 /* At this point:  (!vma || addr < vma->vm_end). */
167                 if (TASK_SIZE - len < addr) {
168                         /*
169                          * Start a new search - just in case we missed
170                          * some holes.
171                          */
172                         if (start_addr != TASK_UNMAPPED_BASE) {
173                                 start_addr = TASK_UNMAPPED_BASE;
174                                 goto full_search;
175                         }
176                         return -ENOMEM;
177                 }
178
179                 if (!vma || addr + len <= vma->vm_start)
180                         return addr;
181                 addr = ALIGN(vma->vm_end, huge_page_size(h));
182         }
183 }
184 #endif
185
186 static int
187 hugetlbfs_read_actor(struct page *page, unsigned long offset,
188                         char __user *buf, unsigned long count,
189                         unsigned long size)
190 {
191         char *kaddr;
192         unsigned long left, copied = 0;
193         int i, chunksize;
194
195         if (size > count)
196                 size = count;
197
198         /* Find which 4k chunk and offset with in that chunk */
199         i = offset >> PAGE_CACHE_SHIFT;
200         offset = offset & ~PAGE_CACHE_MASK;
201
202         while (size) {
203                 chunksize = PAGE_CACHE_SIZE;
204                 if (offset)
205                         chunksize -= offset;
206                 if (chunksize > size)
207                         chunksize = size;
208                 kaddr = kmap(&page[i]);
209                 left = __copy_to_user(buf, kaddr + offset, chunksize);
210                 kunmap(&page[i]);
211                 if (left) {
212                         copied += (chunksize - left);
213                         break;
214                 }
215                 offset = 0;
216                 size -= chunksize;
217                 buf += chunksize;
218                 copied += chunksize;
219                 i++;
220         }
221         return copied ? copied : -EFAULT;
222 }
223
224 /*
225  * Support for read() - Find the page attached to f_mapping and copy out the
226  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
227  * since it has PAGE_CACHE_SIZE assumptions.
228  */
229 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
230                               size_t len, loff_t *ppos)
231 {
232         struct hstate *h = hstate_file(filp);
233         struct address_space *mapping = filp->f_mapping;
234         struct inode *inode = mapping->host;
235         unsigned long index = *ppos >> huge_page_shift(h);
236         unsigned long offset = *ppos & ~huge_page_mask(h);
237         unsigned long end_index;
238         loff_t isize;
239         ssize_t retval = 0;
240
241         mutex_lock(&inode->i_mutex);
242
243         /* validate length */
244         if (len == 0)
245                 goto out;
246
247         isize = i_size_read(inode);
248         if (!isize)
249                 goto out;
250
251         end_index = (isize - 1) >> huge_page_shift(h);
252         for (;;) {
253                 struct page *page;
254                 unsigned long nr, ret;
255                 int ra;
256
257                 /* nr is the maximum number of bytes to copy from this page */
258                 nr = huge_page_size(h);
259                 if (index >= end_index) {
260                         if (index > end_index)
261                                 goto out;
262                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
263                         if (nr <= offset) {
264                                 goto out;
265                         }
266                 }
267                 nr = nr - offset;
268
269                 /* Find the page */
270                 page = find_get_page(mapping, index);
271                 if (unlikely(page == NULL)) {
272                         /*
273                          * We have a HOLE, zero out the user-buffer for the
274                          * length of the hole or request.
275                          */
276                         ret = len < nr ? len : nr;
277                         if (clear_user(buf, ret))
278                                 ra = -EFAULT;
279                         else
280                                 ra = 0;
281                 } else {
282                         /*
283                          * We have the page, copy it to user space buffer.
284                          */
285                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
286                         ret = ra;
287                 }
288                 if (ra < 0) {
289                         if (retval == 0)
290                                 retval = ra;
291                         if (page)
292                                 page_cache_release(page);
293                         goto out;
294                 }
295
296                 offset += ret;
297                 retval += ret;
298                 len -= ret;
299                 index += offset >> huge_page_shift(h);
300                 offset &= ~huge_page_mask(h);
301
302                 if (page)
303                         page_cache_release(page);
304
305                 /* short read or no more work */
306                 if ((ret != nr) || (len == 0))
307                         break;
308         }
309 out:
310         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
311         mutex_unlock(&inode->i_mutex);
312         return retval;
313 }
314
315 static int hugetlbfs_write_begin(struct file *file,
316                         struct address_space *mapping,
317                         loff_t pos, unsigned len, unsigned flags,
318                         struct page **pagep, void **fsdata)
319 {
320         return -EINVAL;
321 }
322
323 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
324                         loff_t pos, unsigned len, unsigned copied,
325                         struct page *page, void *fsdata)
326 {
327         BUG();
328         return -EINVAL;
329 }
330
331 static void truncate_huge_page(struct page *page)
332 {
333         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
334         ClearPageUptodate(page);
335         delete_from_page_cache(page);
336 }
337
338 static void truncate_hugepages(struct inode *inode, loff_t lstart)
339 {
340         struct hstate *h = hstate_inode(inode);
341         struct address_space *mapping = &inode->i_data;
342         const pgoff_t start = lstart >> huge_page_shift(h);
343         struct pagevec pvec;
344         pgoff_t next;
345         int i, freed = 0;
346
347         pagevec_init(&pvec, 0);
348         next = start;
349         while (1) {
350                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
351                         if (next == start)
352                                 break;
353                         next = start;
354                         continue;
355                 }
356
357                 for (i = 0; i < pagevec_count(&pvec); ++i) {
358                         struct page *page = pvec.pages[i];
359
360                         lock_page(page);
361                         if (page->index > next)
362                                 next = page->index;
363                         ++next;
364                         truncate_huge_page(page);
365                         unlock_page(page);
366                         freed++;
367                 }
368                 huge_pagevec_release(&pvec);
369         }
370         BUG_ON(!lstart && mapping->nrpages);
371         hugetlb_unreserve_pages(inode, start, freed);
372 }
373
374 static void hugetlbfs_evict_inode(struct inode *inode)
375 {
376         truncate_hugepages(inode, 0);
377         end_writeback(inode);
378 }
379
380 static inline void
381 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
382 {
383         struct vm_area_struct *vma;
384         struct prio_tree_iter iter;
385
386         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
387                 unsigned long v_offset;
388
389                 /*
390                  * Can the expression below overflow on 32-bit arches?
391                  * No, because the prio_tree returns us only those vmas
392                  * which overlap the truncated area starting at pgoff,
393                  * and no vma on a 32-bit arch can span beyond the 4GB.
394                  */
395                 if (vma->vm_pgoff < pgoff)
396                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
397                 else
398                         v_offset = 0;
399
400                 __unmap_hugepage_range(vma,
401                                 vma->vm_start + v_offset, vma->vm_end, NULL);
402         }
403 }
404
405 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
406 {
407         pgoff_t pgoff;
408         struct address_space *mapping = inode->i_mapping;
409         struct hstate *h = hstate_inode(inode);
410
411         BUG_ON(offset & ~huge_page_mask(h));
412         pgoff = offset >> PAGE_SHIFT;
413
414         i_size_write(inode, offset);
415         mutex_lock(&mapping->i_mmap_mutex);
416         if (!prio_tree_empty(&mapping->i_mmap))
417                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
418         mutex_unlock(&mapping->i_mmap_mutex);
419         truncate_hugepages(inode, offset);
420         return 0;
421 }
422
423 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
424 {
425         struct inode *inode = dentry->d_inode;
426         struct hstate *h = hstate_inode(inode);
427         int error;
428         unsigned int ia_valid = attr->ia_valid;
429
430         BUG_ON(!inode);
431
432         error = inode_change_ok(inode, attr);
433         if (error)
434                 return error;
435
436         if (ia_valid & ATTR_SIZE) {
437                 error = -EINVAL;
438                 if (attr->ia_size & ~huge_page_mask(h))
439                         return -EINVAL;
440                 error = hugetlb_vmtruncate(inode, attr->ia_size);
441                 if (error)
442                         return error;
443         }
444
445         setattr_copy(inode, attr);
446         mark_inode_dirty(inode);
447         return 0;
448 }
449
450 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
451                                         gid_t gid, int mode, dev_t dev)
452 {
453         struct inode *inode;
454
455         inode = new_inode(sb);
456         if (inode) {
457                 struct hugetlbfs_inode_info *info;
458                 inode->i_ino = get_next_ino();
459                 inode->i_mode = mode;
460                 inode->i_uid = uid;
461                 inode->i_gid = gid;
462                 inode->i_mapping->a_ops = &hugetlbfs_aops;
463                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
464                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
465                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
466                 info = HUGETLBFS_I(inode);
467                 /*
468                  * The policy is initialized here even if we are creating a
469                  * private inode because initialization simply creates an
470                  * an empty rb tree and calls spin_lock_init(), later when we
471                  * call mpol_free_shared_policy() it will just return because
472                  * the rb tree will still be empty.
473                  */
474                 mpol_shared_policy_init(&info->policy, NULL);
475                 switch (mode & S_IFMT) {
476                 default:
477                         init_special_inode(inode, mode, dev);
478                         break;
479                 case S_IFREG:
480                         inode->i_op = &hugetlbfs_inode_operations;
481                         inode->i_fop = &hugetlbfs_file_operations;
482                         break;
483                 case S_IFDIR:
484                         inode->i_op = &hugetlbfs_dir_inode_operations;
485                         inode->i_fop = &simple_dir_operations;
486
487                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
488                         inc_nlink(inode);
489                         break;
490                 case S_IFLNK:
491                         inode->i_op = &page_symlink_inode_operations;
492                         break;
493                 }
494                 lockdep_annotate_inode_mutex_key(inode);
495         }
496         return inode;
497 }
498
499 /*
500  * File creation. Allocate an inode, and we're done..
501  */
502 static int hugetlbfs_mknod(struct inode *dir,
503                         struct dentry *dentry, int mode, dev_t dev)
504 {
505         struct inode *inode;
506         int error = -ENOSPC;
507         gid_t gid;
508
509         if (dir->i_mode & S_ISGID) {
510                 gid = dir->i_gid;
511                 if (S_ISDIR(mode))
512                         mode |= S_ISGID;
513         } else {
514                 gid = current_fsgid();
515         }
516         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
517         if (inode) {
518                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
519                 d_instantiate(dentry, inode);
520                 dget(dentry);   /* Extra count - pin the dentry in core */
521                 error = 0;
522         }
523         return error;
524 }
525
526 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
527 {
528         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
529         if (!retval)
530                 inc_nlink(dir);
531         return retval;
532 }
533
534 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
535 {
536         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
537 }
538
539 static int hugetlbfs_symlink(struct inode *dir,
540                         struct dentry *dentry, const char *symname)
541 {
542         struct inode *inode;
543         int error = -ENOSPC;
544         gid_t gid;
545
546         if (dir->i_mode & S_ISGID)
547                 gid = dir->i_gid;
548         else
549                 gid = current_fsgid();
550
551         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
552                                         gid, S_IFLNK|S_IRWXUGO, 0);
553         if (inode) {
554                 int l = strlen(symname)+1;
555                 error = page_symlink(inode, symname, l);
556                 if (!error) {
557                         d_instantiate(dentry, inode);
558                         dget(dentry);
559                 } else
560                         iput(inode);
561         }
562         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
563
564         return error;
565 }
566
567 /*
568  * mark the head page dirty
569  */
570 static int hugetlbfs_set_page_dirty(struct page *page)
571 {
572         struct page *head = compound_head(page);
573
574         SetPageDirty(head);
575         return 0;
576 }
577
578 static int hugetlbfs_migrate_page(struct address_space *mapping,
579                                 struct page *newpage, struct page *page)
580 {
581         int rc;
582
583         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
584         if (rc)
585                 return rc;
586         migrate_page_copy(newpage, page);
587
588         return 0;
589 }
590
591 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
592 {
593         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
594         struct hstate *h = hstate_inode(dentry->d_inode);
595
596         buf->f_type = HUGETLBFS_MAGIC;
597         buf->f_bsize = huge_page_size(h);
598         if (sbinfo) {
599                 spin_lock(&sbinfo->stat_lock);
600                 /* If no limits set, just report 0 for max/free/used
601                  * blocks, like simple_statfs() */
602                 if (sbinfo->max_blocks >= 0) {
603                         buf->f_blocks = sbinfo->max_blocks;
604                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
605                         buf->f_files = sbinfo->max_inodes;
606                         buf->f_ffree = sbinfo->free_inodes;
607                 }
608                 spin_unlock(&sbinfo->stat_lock);
609         }
610         buf->f_namelen = NAME_MAX;
611         return 0;
612 }
613
614 static void hugetlbfs_put_super(struct super_block *sb)
615 {
616         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
617
618         if (sbi) {
619                 sb->s_fs_info = NULL;
620                 kfree(sbi);
621         }
622 }
623
624 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
625 {
626         if (sbinfo->free_inodes >= 0) {
627                 spin_lock(&sbinfo->stat_lock);
628                 if (unlikely(!sbinfo->free_inodes)) {
629                         spin_unlock(&sbinfo->stat_lock);
630                         return 0;
631                 }
632                 sbinfo->free_inodes--;
633                 spin_unlock(&sbinfo->stat_lock);
634         }
635
636         return 1;
637 }
638
639 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
640 {
641         if (sbinfo->free_inodes >= 0) {
642                 spin_lock(&sbinfo->stat_lock);
643                 sbinfo->free_inodes++;
644                 spin_unlock(&sbinfo->stat_lock);
645         }
646 }
647
648
649 static struct kmem_cache *hugetlbfs_inode_cachep;
650
651 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
652 {
653         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
654         struct hugetlbfs_inode_info *p;
655
656         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
657                 return NULL;
658         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
659         if (unlikely(!p)) {
660                 hugetlbfs_inc_free_inodes(sbinfo);
661                 return NULL;
662         }
663         return &p->vfs_inode;
664 }
665
666 static void hugetlbfs_i_callback(struct rcu_head *head)
667 {
668         struct inode *inode = container_of(head, struct inode, i_rcu);
669         INIT_LIST_HEAD(&inode->i_dentry);
670         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
671 }
672
673 static void hugetlbfs_destroy_inode(struct inode *inode)
674 {
675         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
676         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
677         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
678 }
679
680 static const struct address_space_operations hugetlbfs_aops = {
681         .write_begin    = hugetlbfs_write_begin,
682         .write_end      = hugetlbfs_write_end,
683         .set_page_dirty = hugetlbfs_set_page_dirty,
684         .migratepage    = hugetlbfs_migrate_page,
685 };
686
687
688 static void init_once(void *foo)
689 {
690         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
691
692         inode_init_once(&ei->vfs_inode);
693 }
694
695 const struct file_operations hugetlbfs_file_operations = {
696         .read                   = hugetlbfs_read,
697         .mmap                   = hugetlbfs_file_mmap,
698         .fsync                  = noop_fsync,
699         .get_unmapped_area      = hugetlb_get_unmapped_area,
700         .llseek         = default_llseek,
701 };
702
703 static const struct inode_operations hugetlbfs_dir_inode_operations = {
704         .create         = hugetlbfs_create,
705         .lookup         = simple_lookup,
706         .link           = simple_link,
707         .unlink         = simple_unlink,
708         .symlink        = hugetlbfs_symlink,
709         .mkdir          = hugetlbfs_mkdir,
710         .rmdir          = simple_rmdir,
711         .mknod          = hugetlbfs_mknod,
712         .rename         = simple_rename,
713         .setattr        = hugetlbfs_setattr,
714 };
715
716 static const struct inode_operations hugetlbfs_inode_operations = {
717         .setattr        = hugetlbfs_setattr,
718 };
719
720 static const struct super_operations hugetlbfs_ops = {
721         .alloc_inode    = hugetlbfs_alloc_inode,
722         .destroy_inode  = hugetlbfs_destroy_inode,
723         .evict_inode    = hugetlbfs_evict_inode,
724         .statfs         = hugetlbfs_statfs,
725         .put_super      = hugetlbfs_put_super,
726         .show_options   = generic_show_options,
727 };
728
729 static int
730 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
731 {
732         char *p, *rest;
733         substring_t args[MAX_OPT_ARGS];
734         int option;
735         unsigned long long size = 0;
736         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
737
738         if (!options)
739                 return 0;
740
741         while ((p = strsep(&options, ",")) != NULL) {
742                 int token;
743                 if (!*p)
744                         continue;
745
746                 token = match_token(p, tokens, args);
747                 switch (token) {
748                 case Opt_uid:
749                         if (match_int(&args[0], &option))
750                                 goto bad_val;
751                         pconfig->uid = option;
752                         break;
753
754                 case Opt_gid:
755                         if (match_int(&args[0], &option))
756                                 goto bad_val;
757                         pconfig->gid = option;
758                         break;
759
760                 case Opt_mode:
761                         if (match_octal(&args[0], &option))
762                                 goto bad_val;
763                         pconfig->mode = option & 01777U;
764                         break;
765
766                 case Opt_size: {
767                         /* memparse() will accept a K/M/G without a digit */
768                         if (!isdigit(*args[0].from))
769                                 goto bad_val;
770                         size = memparse(args[0].from, &rest);
771                         setsize = SIZE_STD;
772                         if (*rest == '%')
773                                 setsize = SIZE_PERCENT;
774                         break;
775                 }
776
777                 case Opt_nr_inodes:
778                         /* memparse() will accept a K/M/G without a digit */
779                         if (!isdigit(*args[0].from))
780                                 goto bad_val;
781                         pconfig->nr_inodes = memparse(args[0].from, &rest);
782                         break;
783
784                 case Opt_pagesize: {
785                         unsigned long ps;
786                         ps = memparse(args[0].from, &rest);
787                         pconfig->hstate = size_to_hstate(ps);
788                         if (!pconfig->hstate) {
789                                 printk(KERN_ERR
790                                 "hugetlbfs: Unsupported page size %lu MB\n",
791                                         ps >> 20);
792                                 return -EINVAL;
793                         }
794                         break;
795                 }
796
797                 default:
798                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
799                                  p);
800                         return -EINVAL;
801                         break;
802                 }
803         }
804
805         /* Do size after hstate is set up */
806         if (setsize > NO_SIZE) {
807                 struct hstate *h = pconfig->hstate;
808                 if (setsize == SIZE_PERCENT) {
809                         size <<= huge_page_shift(h);
810                         size *= h->max_huge_pages;
811                         do_div(size, 100);
812                 }
813                 pconfig->nr_blocks = (size >> huge_page_shift(h));
814         }
815
816         return 0;
817
818 bad_val:
819         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
820                args[0].from, p);
821         return -EINVAL;
822 }
823
824 static int
825 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
826 {
827         struct inode * inode;
828         struct dentry * root;
829         int ret;
830         struct hugetlbfs_config config;
831         struct hugetlbfs_sb_info *sbinfo;
832
833         save_mount_options(sb, data);
834
835         config.nr_blocks = -1; /* No limit on size by default */
836         config.nr_inodes = -1; /* No limit on number of inodes by default */
837         config.uid = current_fsuid();
838         config.gid = current_fsgid();
839         config.mode = 0755;
840         config.hstate = &default_hstate;
841         ret = hugetlbfs_parse_options(data, &config);
842         if (ret)
843                 return ret;
844
845         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
846         if (!sbinfo)
847                 return -ENOMEM;
848         sb->s_fs_info = sbinfo;
849         sbinfo->hstate = config.hstate;
850         spin_lock_init(&sbinfo->stat_lock);
851         sbinfo->max_blocks = config.nr_blocks;
852         sbinfo->free_blocks = config.nr_blocks;
853         sbinfo->max_inodes = config.nr_inodes;
854         sbinfo->free_inodes = config.nr_inodes;
855         sb->s_maxbytes = MAX_LFS_FILESIZE;
856         sb->s_blocksize = huge_page_size(config.hstate);
857         sb->s_blocksize_bits = huge_page_shift(config.hstate);
858         sb->s_magic = HUGETLBFS_MAGIC;
859         sb->s_op = &hugetlbfs_ops;
860         sb->s_time_gran = 1;
861         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
862                                         S_IFDIR | config.mode, 0);
863         if (!inode)
864                 goto out_free;
865
866         root = d_alloc_root(inode);
867         if (!root) {
868                 iput(inode);
869                 goto out_free;
870         }
871         sb->s_root = root;
872         return 0;
873 out_free:
874         kfree(sbinfo);
875         return -ENOMEM;
876 }
877
878 int hugetlb_get_quota(struct address_space *mapping, long delta)
879 {
880         int ret = 0;
881         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
882
883         if (sbinfo->free_blocks > -1) {
884                 spin_lock(&sbinfo->stat_lock);
885                 if (sbinfo->free_blocks - delta >= 0)
886                         sbinfo->free_blocks -= delta;
887                 else
888                         ret = -ENOMEM;
889                 spin_unlock(&sbinfo->stat_lock);
890         }
891
892         return ret;
893 }
894
895 void hugetlb_put_quota(struct address_space *mapping, long delta)
896 {
897         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
898
899         if (sbinfo->free_blocks > -1) {
900                 spin_lock(&sbinfo->stat_lock);
901                 sbinfo->free_blocks += delta;
902                 spin_unlock(&sbinfo->stat_lock);
903         }
904 }
905
906 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
907         int flags, const char *dev_name, void *data)
908 {
909         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
910 }
911
912 static struct file_system_type hugetlbfs_fs_type = {
913         .name           = "hugetlbfs",
914         .mount          = hugetlbfs_mount,
915         .kill_sb        = kill_litter_super,
916 };
917
918 static struct vfsmount *hugetlbfs_vfsmount;
919
920 static int can_do_hugetlb_shm(void)
921 {
922         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
923 }
924
925 struct file *hugetlb_file_setup(const char *name, size_t size,
926                                 vm_flags_t acctflag,
927                                 struct user_struct **user, int creat_flags)
928 {
929         int error = -ENOMEM;
930         struct file *file;
931         struct inode *inode;
932         struct path path;
933         struct dentry *root;
934         struct qstr quick_string;
935
936         *user = NULL;
937         if (!hugetlbfs_vfsmount)
938                 return ERR_PTR(-ENOENT);
939
940         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
941                 *user = current_user();
942                 if (user_shm_lock(size, *user)) {
943                         printk_once(KERN_WARNING "Using mlock ulimits for SHM_HUGETLB is deprecated\n");
944                 } else {
945                         *user = NULL;
946                         return ERR_PTR(-EPERM);
947                 }
948         }
949
950         root = hugetlbfs_vfsmount->mnt_root;
951         quick_string.name = name;
952         quick_string.len = strlen(quick_string.name);
953         quick_string.hash = 0;
954         path.dentry = d_alloc(root, &quick_string);
955         if (!path.dentry)
956                 goto out_shm_unlock;
957
958         path.mnt = mntget(hugetlbfs_vfsmount);
959         error = -ENOSPC;
960         inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
961                                 current_fsgid(), S_IFREG | S_IRWXUGO, 0);
962         if (!inode)
963                 goto out_dentry;
964
965         error = -ENOMEM;
966         if (hugetlb_reserve_pages(inode, 0,
967                         size >> huge_page_shift(hstate_inode(inode)), NULL,
968                         acctflag))
969                 goto out_inode;
970
971         d_instantiate(path.dentry, inode);
972         inode->i_size = size;
973         clear_nlink(inode);
974
975         error = -ENFILE;
976         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
977                         &hugetlbfs_file_operations);
978         if (!file)
979                 goto out_dentry; /* inode is already attached */
980
981         return file;
982
983 out_inode:
984         iput(inode);
985 out_dentry:
986         path_put(&path);
987 out_shm_unlock:
988         if (*user) {
989                 user_shm_unlock(size, *user);
990                 *user = NULL;
991         }
992         return ERR_PTR(error);
993 }
994
995 static int __init init_hugetlbfs_fs(void)
996 {
997         int error;
998         struct vfsmount *vfsmount;
999
1000         error = bdi_init(&hugetlbfs_backing_dev_info);
1001         if (error)
1002                 return error;
1003
1004         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1005                                         sizeof(struct hugetlbfs_inode_info),
1006                                         0, 0, init_once);
1007         if (hugetlbfs_inode_cachep == NULL)
1008                 goto out2;
1009
1010         error = register_filesystem(&hugetlbfs_fs_type);
1011         if (error)
1012                 goto out;
1013
1014         vfsmount = kern_mount(&hugetlbfs_fs_type);
1015
1016         if (!IS_ERR(vfsmount)) {
1017                 hugetlbfs_vfsmount = vfsmount;
1018                 return 0;
1019         }
1020
1021         error = PTR_ERR(vfsmount);
1022
1023  out:
1024         if (error)
1025                 kmem_cache_destroy(hugetlbfs_inode_cachep);
1026  out2:
1027         bdi_destroy(&hugetlbfs_backing_dev_info);
1028         return error;
1029 }
1030
1031 static void __exit exit_hugetlbfs_fs(void)
1032 {
1033         kmem_cache_destroy(hugetlbfs_inode_cachep);
1034         kern_unmount(hugetlbfs_vfsmount);
1035         unregister_filesystem(&hugetlbfs_fs_type);
1036         bdi_destroy(&hugetlbfs_backing_dev_info);
1037 }
1038
1039 module_init(init_hugetlbfs_fs)
1040 module_exit(exit_hugetlbfs_fs)
1041
1042 MODULE_LICENSE("GPL");