bc56df8ce0010e9c0082203ef42e95f1b12308d6
[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/quotaops.h>
30 #include <linux/slab.h>
31 #include <linux/dnotify.h>
32 #include <linux/statfs.h>
33 #include <linux/security.h>
34
35 #include <asm/uaccess.h>
36
37 /* some random number */
38 #define HUGETLBFS_MAGIC 0x958458f6
39
40 static const struct super_operations hugetlbfs_ops;
41 static const struct address_space_operations hugetlbfs_aops;
42 const struct file_operations hugetlbfs_file_operations;
43 static const struct inode_operations hugetlbfs_dir_inode_operations;
44 static const struct inode_operations hugetlbfs_inode_operations;
45
46 static struct backing_dev_info hugetlbfs_backing_dev_info = {
47         .ra_pages       = 0,    /* No readahead */
48         .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
49 };
50
51 int sysctl_hugetlb_shm_group;
52
53 enum {
54         Opt_size, Opt_nr_inodes,
55         Opt_mode, Opt_uid, Opt_gid,
56         Opt_pagesize,
57         Opt_err,
58 };
59
60 static const match_table_t tokens = {
61         {Opt_size,      "size=%s"},
62         {Opt_nr_inodes, "nr_inodes=%s"},
63         {Opt_mode,      "mode=%o"},
64         {Opt_uid,       "uid=%u"},
65         {Opt_gid,       "gid=%u"},
66         {Opt_pagesize,  "pagesize=%s"},
67         {Opt_err,       NULL},
68 };
69
70 static void huge_pagevec_release(struct pagevec *pvec)
71 {
72         int i;
73
74         for (i = 0; i < pagevec_count(pvec); ++i)
75                 put_page(pvec->pages[i]);
76
77         pagevec_reinit(pvec);
78 }
79
80 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
81 {
82         struct inode *inode = file->f_path.dentry->d_inode;
83         loff_t len, vma_len;
84         int ret;
85         struct hstate *h = hstate_file(file);
86
87         /*
88          * vma address alignment (but not the pgoff alignment) has
89          * already been checked by prepare_hugepage_range.  If you add
90          * any error returns here, do so after setting VM_HUGETLB, so
91          * is_vm_hugetlb_page tests below unmap_region go the right
92          * way when do_mmap_pgoff unwinds (may be important on powerpc
93          * and ia64).
94          */
95         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
96         vma->vm_ops = &hugetlb_vm_ops;
97
98         if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
99                 return -EINVAL;
100
101         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
102
103         mutex_lock(&inode->i_mutex);
104         file_accessed(file);
105
106         ret = -ENOMEM;
107         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
108
109         if (hugetlb_reserve_pages(inode,
110                                 vma->vm_pgoff >> huge_page_order(h),
111                                 len >> huge_page_shift(h), vma,
112                                 vma->vm_flags))
113                 goto out;
114
115         ret = 0;
116         hugetlb_prefault_arch_hook(vma->vm_mm);
117         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
118                 inode->i_size = len;
119 out:
120         mutex_unlock(&inode->i_mutex);
121
122         return ret;
123 }
124
125 /*
126  * Called under down_write(mmap_sem).
127  */
128
129 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
130 static unsigned long
131 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
132                 unsigned long len, unsigned long pgoff, unsigned long flags)
133 {
134         struct mm_struct *mm = current->mm;
135         struct vm_area_struct *vma;
136         unsigned long start_addr;
137         struct hstate *h = hstate_file(file);
138
139         if (len & ~huge_page_mask(h))
140                 return -EINVAL;
141         if (len > TASK_SIZE)
142                 return -ENOMEM;
143
144         if (flags & MAP_FIXED) {
145                 if (prepare_hugepage_range(file, addr, len))
146                         return -EINVAL;
147                 return addr;
148         }
149
150         if (addr) {
151                 addr = ALIGN(addr, huge_page_size(h));
152                 vma = find_vma(mm, addr);
153                 if (TASK_SIZE - len >= addr &&
154                     (!vma || addr + len <= vma->vm_start))
155                         return addr;
156         }
157
158         start_addr = mm->free_area_cache;
159
160         if (len <= mm->cached_hole_size)
161                 start_addr = TASK_UNMAPPED_BASE;
162
163 full_search:
164         addr = ALIGN(start_addr, huge_page_size(h));
165
166         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
167                 /* At this point:  (!vma || addr < vma->vm_end). */
168                 if (TASK_SIZE - len < addr) {
169                         /*
170                          * Start a new search - just in case we missed
171                          * some holes.
172                          */
173                         if (start_addr != TASK_UNMAPPED_BASE) {
174                                 start_addr = TASK_UNMAPPED_BASE;
175                                 goto full_search;
176                         }
177                         return -ENOMEM;
178                 }
179
180                 if (!vma || addr + len <= vma->vm_start)
181                         return addr;
182                 addr = ALIGN(vma->vm_end, huge_page_size(h));
183         }
184 }
185 #endif
186
187 static int
188 hugetlbfs_read_actor(struct page *page, unsigned long offset,
189                         char __user *buf, unsigned long count,
190                         unsigned long size)
191 {
192         char *kaddr;
193         unsigned long left, copied = 0;
194         int i, chunksize;
195
196         if (size > count)
197                 size = count;
198
199         /* Find which 4k chunk and offset with in that chunk */
200         i = offset >> PAGE_CACHE_SHIFT;
201         offset = offset & ~PAGE_CACHE_MASK;
202
203         while (size) {
204                 chunksize = PAGE_CACHE_SIZE;
205                 if (offset)
206                         chunksize -= offset;
207                 if (chunksize > size)
208                         chunksize = size;
209                 kaddr = kmap(&page[i]);
210                 left = __copy_to_user(buf, kaddr + offset, chunksize);
211                 kunmap(&page[i]);
212                 if (left) {
213                         copied += (chunksize - left);
214                         break;
215                 }
216                 offset = 0;
217                 size -= chunksize;
218                 buf += chunksize;
219                 copied += chunksize;
220                 i++;
221         }
222         return copied ? copied : -EFAULT;
223 }
224
225 /*
226  * Support for read() - Find the page attached to f_mapping and copy out the
227  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
228  * since it has PAGE_CACHE_SIZE assumptions.
229  */
230 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
231                               size_t len, loff_t *ppos)
232 {
233         struct hstate *h = hstate_file(filp);
234         struct address_space *mapping = filp->f_mapping;
235         struct inode *inode = mapping->host;
236         unsigned long index = *ppos >> huge_page_shift(h);
237         unsigned long offset = *ppos & ~huge_page_mask(h);
238         unsigned long end_index;
239         loff_t isize;
240         ssize_t retval = 0;
241
242         mutex_lock(&inode->i_mutex);
243
244         /* validate length */
245         if (len == 0)
246                 goto out;
247
248         isize = i_size_read(inode);
249         if (!isize)
250                 goto out;
251
252         end_index = (isize - 1) >> huge_page_shift(h);
253         for (;;) {
254                 struct page *page;
255                 unsigned long nr, ret;
256                 int ra;
257
258                 /* nr is the maximum number of bytes to copy from this page */
259                 nr = huge_page_size(h);
260                 if (index >= end_index) {
261                         if (index > end_index)
262                                 goto out;
263                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
264                         if (nr <= offset) {
265                                 goto out;
266                         }
267                 }
268                 nr = nr - offset;
269
270                 /* Find the page */
271                 page = find_get_page(mapping, index);
272                 if (unlikely(page == NULL)) {
273                         /*
274                          * We have a HOLE, zero out the user-buffer for the
275                          * length of the hole or request.
276                          */
277                         ret = len < nr ? len : nr;
278                         if (clear_user(buf, ret))
279                                 ra = -EFAULT;
280                         else
281                                 ra = 0;
282                 } else {
283                         /*
284                          * We have the page, copy it to user space buffer.
285                          */
286                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
287                         ret = ra;
288                 }
289                 if (ra < 0) {
290                         if (retval == 0)
291                                 retval = ra;
292                         if (page)
293                                 page_cache_release(page);
294                         goto out;
295                 }
296
297                 offset += ret;
298                 retval += ret;
299                 len -= ret;
300                 index += offset >> huge_page_shift(h);
301                 offset &= ~huge_page_mask(h);
302
303                 if (page)
304                         page_cache_release(page);
305
306                 /* short read or no more work */
307                 if ((ret != nr) || (len == 0))
308                         break;
309         }
310 out:
311         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
312         mutex_unlock(&inode->i_mutex);
313         return retval;
314 }
315
316 /*
317  * Read a page. Again trivial. If it didn't already exist
318  * in the page cache, it is zero-filled.
319  */
320 static int hugetlbfs_readpage(struct file *file, struct page * page)
321 {
322         unlock_page(page);
323         return -EINVAL;
324 }
325
326 static int hugetlbfs_write_begin(struct file *file,
327                         struct address_space *mapping,
328                         loff_t pos, unsigned len, unsigned flags,
329                         struct page **pagep, void **fsdata)
330 {
331         return -EINVAL;
332 }
333
334 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
335                         loff_t pos, unsigned len, unsigned copied,
336                         struct page *page, void *fsdata)
337 {
338         BUG();
339         return -EINVAL;
340 }
341
342 static void truncate_huge_page(struct page *page)
343 {
344         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
345         ClearPageUptodate(page);
346         remove_from_page_cache(page);
347         put_page(page);
348 }
349
350 static void truncate_hugepages(struct inode *inode, loff_t lstart)
351 {
352         struct hstate *h = hstate_inode(inode);
353         struct address_space *mapping = &inode->i_data;
354         const pgoff_t start = lstart >> huge_page_shift(h);
355         struct pagevec pvec;
356         pgoff_t next;
357         int i, freed = 0;
358
359         pagevec_init(&pvec, 0);
360         next = start;
361         while (1) {
362                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
363                         if (next == start)
364                                 break;
365                         next = start;
366                         continue;
367                 }
368
369                 for (i = 0; i < pagevec_count(&pvec); ++i) {
370                         struct page *page = pvec.pages[i];
371
372                         lock_page(page);
373                         if (page->index > next)
374                                 next = page->index;
375                         ++next;
376                         truncate_huge_page(page);
377                         unlock_page(page);
378                         freed++;
379                 }
380                 huge_pagevec_release(&pvec);
381         }
382         BUG_ON(!lstart && mapping->nrpages);
383         hugetlb_unreserve_pages(inode, start, freed);
384 }
385
386 static void hugetlbfs_delete_inode(struct inode *inode)
387 {
388         truncate_hugepages(inode, 0);
389         clear_inode(inode);
390 }
391
392 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
393 {
394         struct super_block *sb = inode->i_sb;
395
396         if (!hlist_unhashed(&inode->i_hash)) {
397                 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
398                         list_move(&inode->i_list, &inode_unused);
399                 inodes_stat.nr_unused++;
400                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
401                         spin_unlock(&inode_lock);
402                         return;
403                 }
404                 inode->i_state |= I_WILL_FREE;
405                 spin_unlock(&inode_lock);
406                 /*
407                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
408                  * in our backing_dev_info.
409                  */
410                 write_inode_now(inode, 1);
411                 spin_lock(&inode_lock);
412                 inode->i_state &= ~I_WILL_FREE;
413                 inodes_stat.nr_unused--;
414                 hlist_del_init(&inode->i_hash);
415         }
416         list_del_init(&inode->i_list);
417         list_del_init(&inode->i_sb_list);
418         inode->i_state |= I_FREEING;
419         inodes_stat.nr_inodes--;
420         spin_unlock(&inode_lock);
421         truncate_hugepages(inode, 0);
422         clear_inode(inode);
423         destroy_inode(inode);
424 }
425
426 static void hugetlbfs_drop_inode(struct inode *inode)
427 {
428         if (!inode->i_nlink)
429                 generic_delete_inode(inode);
430         else
431                 hugetlbfs_forget_inode(inode);
432 }
433
434 static inline void
435 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
436 {
437         struct vm_area_struct *vma;
438         struct prio_tree_iter iter;
439
440         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
441                 unsigned long v_offset;
442
443                 /*
444                  * Can the expression below overflow on 32-bit arches?
445                  * No, because the prio_tree returns us only those vmas
446                  * which overlap the truncated area starting at pgoff,
447                  * and no vma on a 32-bit arch can span beyond the 4GB.
448                  */
449                 if (vma->vm_pgoff < pgoff)
450                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
451                 else
452                         v_offset = 0;
453
454                 __unmap_hugepage_range(vma,
455                                 vma->vm_start + v_offset, vma->vm_end, NULL);
456         }
457 }
458
459 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
460 {
461         pgoff_t pgoff;
462         struct address_space *mapping = inode->i_mapping;
463         struct hstate *h = hstate_inode(inode);
464
465         BUG_ON(offset & ~huge_page_mask(h));
466         pgoff = offset >> PAGE_SHIFT;
467
468         i_size_write(inode, offset);
469         spin_lock(&mapping->i_mmap_lock);
470         if (!prio_tree_empty(&mapping->i_mmap))
471                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
472         spin_unlock(&mapping->i_mmap_lock);
473         truncate_hugepages(inode, offset);
474         return 0;
475 }
476
477 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
478 {
479         struct inode *inode = dentry->d_inode;
480         struct hstate *h = hstate_inode(inode);
481         int error;
482         unsigned int ia_valid = attr->ia_valid;
483
484         BUG_ON(!inode);
485
486         error = inode_change_ok(inode, attr);
487         if (error)
488                 goto out;
489
490         if (ia_valid & ATTR_SIZE) {
491                 error = -EINVAL;
492                 if (!(attr->ia_size & ~huge_page_mask(h)))
493                         error = hugetlb_vmtruncate(inode, attr->ia_size);
494                 if (error)
495                         goto out;
496                 attr->ia_valid &= ~ATTR_SIZE;
497         }
498         error = inode_setattr(inode, attr);
499 out:
500         return error;
501 }
502
503 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
504                                         gid_t gid, int mode, dev_t dev)
505 {
506         struct inode *inode;
507
508         inode = new_inode(sb);
509         if (inode) {
510                 struct hugetlbfs_inode_info *info;
511                 inode->i_mode = mode;
512                 inode->i_uid = uid;
513                 inode->i_gid = gid;
514                 inode->i_mapping->a_ops = &hugetlbfs_aops;
515                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
516                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
517                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
518                 info = HUGETLBFS_I(inode);
519                 mpol_shared_policy_init(&info->policy, NULL);
520                 switch (mode & S_IFMT) {
521                 default:
522                         init_special_inode(inode, mode, dev);
523                         break;
524                 case S_IFREG:
525                         inode->i_op = &hugetlbfs_inode_operations;
526                         inode->i_fop = &hugetlbfs_file_operations;
527                         break;
528                 case S_IFDIR:
529                         inode->i_op = &hugetlbfs_dir_inode_operations;
530                         inode->i_fop = &simple_dir_operations;
531
532                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
533                         inc_nlink(inode);
534                         break;
535                 case S_IFLNK:
536                         inode->i_op = &page_symlink_inode_operations;
537                         break;
538                 }
539         }
540         return inode;
541 }
542
543 /*
544  * File creation. Allocate an inode, and we're done..
545  */
546 static int hugetlbfs_mknod(struct inode *dir,
547                         struct dentry *dentry, int mode, dev_t dev)
548 {
549         struct inode *inode;
550         int error = -ENOSPC;
551         gid_t gid;
552
553         if (dir->i_mode & S_ISGID) {
554                 gid = dir->i_gid;
555                 if (S_ISDIR(mode))
556                         mode |= S_ISGID;
557         } else {
558                 gid = current_fsgid();
559         }
560         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
561         if (inode) {
562                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
563                 d_instantiate(dentry, inode);
564                 dget(dentry);   /* Extra count - pin the dentry in core */
565                 error = 0;
566         }
567         return error;
568 }
569
570 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
571 {
572         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
573         if (!retval)
574                 inc_nlink(dir);
575         return retval;
576 }
577
578 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
579 {
580         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
581 }
582
583 static int hugetlbfs_symlink(struct inode *dir,
584                         struct dentry *dentry, const char *symname)
585 {
586         struct inode *inode;
587         int error = -ENOSPC;
588         gid_t gid;
589
590         if (dir->i_mode & S_ISGID)
591                 gid = dir->i_gid;
592         else
593                 gid = current_fsgid();
594
595         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
596                                         gid, S_IFLNK|S_IRWXUGO, 0);
597         if (inode) {
598                 int l = strlen(symname)+1;
599                 error = page_symlink(inode, symname, l);
600                 if (!error) {
601                         d_instantiate(dentry, inode);
602                         dget(dentry);
603                 } else
604                         iput(inode);
605         }
606         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
607
608         return error;
609 }
610
611 /*
612  * mark the head page dirty
613  */
614 static int hugetlbfs_set_page_dirty(struct page *page)
615 {
616         struct page *head = compound_head(page);
617
618         SetPageDirty(head);
619         return 0;
620 }
621
622 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
623 {
624         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
625         struct hstate *h = hstate_inode(dentry->d_inode);
626
627         buf->f_type = HUGETLBFS_MAGIC;
628         buf->f_bsize = huge_page_size(h);
629         if (sbinfo) {
630                 spin_lock(&sbinfo->stat_lock);
631                 /* If no limits set, just report 0 for max/free/used
632                  * blocks, like simple_statfs() */
633                 if (sbinfo->max_blocks >= 0) {
634                         buf->f_blocks = sbinfo->max_blocks;
635                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
636                         buf->f_files = sbinfo->max_inodes;
637                         buf->f_ffree = sbinfo->free_inodes;
638                 }
639                 spin_unlock(&sbinfo->stat_lock);
640         }
641         buf->f_namelen = NAME_MAX;
642         return 0;
643 }
644
645 static void hugetlbfs_put_super(struct super_block *sb)
646 {
647         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
648
649         if (sbi) {
650                 sb->s_fs_info = NULL;
651                 kfree(sbi);
652         }
653 }
654
655 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
656 {
657         if (sbinfo->free_inodes >= 0) {
658                 spin_lock(&sbinfo->stat_lock);
659                 if (unlikely(!sbinfo->free_inodes)) {
660                         spin_unlock(&sbinfo->stat_lock);
661                         return 0;
662                 }
663                 sbinfo->free_inodes--;
664                 spin_unlock(&sbinfo->stat_lock);
665         }
666
667         return 1;
668 }
669
670 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
671 {
672         if (sbinfo->free_inodes >= 0) {
673                 spin_lock(&sbinfo->stat_lock);
674                 sbinfo->free_inodes++;
675                 spin_unlock(&sbinfo->stat_lock);
676         }
677 }
678
679
680 static struct kmem_cache *hugetlbfs_inode_cachep;
681
682 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
683 {
684         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
685         struct hugetlbfs_inode_info *p;
686
687         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
688                 return NULL;
689         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
690         if (unlikely(!p)) {
691                 hugetlbfs_inc_free_inodes(sbinfo);
692                 return NULL;
693         }
694         return &p->vfs_inode;
695 }
696
697 static void hugetlbfs_destroy_inode(struct inode *inode)
698 {
699         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
700         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
701         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
702 }
703
704 static const struct address_space_operations hugetlbfs_aops = {
705         .readpage       = hugetlbfs_readpage,
706         .write_begin    = hugetlbfs_write_begin,
707         .write_end      = hugetlbfs_write_end,
708         .set_page_dirty = hugetlbfs_set_page_dirty,
709 };
710
711
712 static void init_once(void *foo)
713 {
714         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
715
716         inode_init_once(&ei->vfs_inode);
717 }
718
719 const struct file_operations hugetlbfs_file_operations = {
720         .read                   = hugetlbfs_read,
721         .mmap                   = hugetlbfs_file_mmap,
722         .fsync                  = simple_sync_file,
723         .get_unmapped_area      = hugetlb_get_unmapped_area,
724 };
725
726 static const struct inode_operations hugetlbfs_dir_inode_operations = {
727         .create         = hugetlbfs_create,
728         .lookup         = simple_lookup,
729         .link           = simple_link,
730         .unlink         = simple_unlink,
731         .symlink        = hugetlbfs_symlink,
732         .mkdir          = hugetlbfs_mkdir,
733         .rmdir          = simple_rmdir,
734         .mknod          = hugetlbfs_mknod,
735         .rename         = simple_rename,
736         .setattr        = hugetlbfs_setattr,
737 };
738
739 static const struct inode_operations hugetlbfs_inode_operations = {
740         .setattr        = hugetlbfs_setattr,
741 };
742
743 static const struct super_operations hugetlbfs_ops = {
744         .alloc_inode    = hugetlbfs_alloc_inode,
745         .destroy_inode  = hugetlbfs_destroy_inode,
746         .statfs         = hugetlbfs_statfs,
747         .delete_inode   = hugetlbfs_delete_inode,
748         .drop_inode     = hugetlbfs_drop_inode,
749         .put_super      = hugetlbfs_put_super,
750         .show_options   = generic_show_options,
751 };
752
753 static int
754 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
755 {
756         char *p, *rest;
757         substring_t args[MAX_OPT_ARGS];
758         int option;
759         unsigned long long size = 0;
760         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
761
762         if (!options)
763                 return 0;
764
765         while ((p = strsep(&options, ",")) != NULL) {
766                 int token;
767                 if (!*p)
768                         continue;
769
770                 token = match_token(p, tokens, args);
771                 switch (token) {
772                 case Opt_uid:
773                         if (match_int(&args[0], &option))
774                                 goto bad_val;
775                         pconfig->uid = option;
776                         break;
777
778                 case Opt_gid:
779                         if (match_int(&args[0], &option))
780                                 goto bad_val;
781                         pconfig->gid = option;
782                         break;
783
784                 case Opt_mode:
785                         if (match_octal(&args[0], &option))
786                                 goto bad_val;
787                         pconfig->mode = option & 01777U;
788                         break;
789
790                 case Opt_size: {
791                         /* memparse() will accept a K/M/G without a digit */
792                         if (!isdigit(*args[0].from))
793                                 goto bad_val;
794                         size = memparse(args[0].from, &rest);
795                         setsize = SIZE_STD;
796                         if (*rest == '%')
797                                 setsize = SIZE_PERCENT;
798                         break;
799                 }
800
801                 case Opt_nr_inodes:
802                         /* memparse() will accept a K/M/G without a digit */
803                         if (!isdigit(*args[0].from))
804                                 goto bad_val;
805                         pconfig->nr_inodes = memparse(args[0].from, &rest);
806                         break;
807
808                 case Opt_pagesize: {
809                         unsigned long ps;
810                         ps = memparse(args[0].from, &rest);
811                         pconfig->hstate = size_to_hstate(ps);
812                         if (!pconfig->hstate) {
813                                 printk(KERN_ERR
814                                 "hugetlbfs: Unsupported page size %lu MB\n",
815                                         ps >> 20);
816                                 return -EINVAL;
817                         }
818                         break;
819                 }
820
821                 default:
822                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
823                                  p);
824                         return -EINVAL;
825                         break;
826                 }
827         }
828
829         /* Do size after hstate is set up */
830         if (setsize > NO_SIZE) {
831                 struct hstate *h = pconfig->hstate;
832                 if (setsize == SIZE_PERCENT) {
833                         size <<= huge_page_shift(h);
834                         size *= h->max_huge_pages;
835                         do_div(size, 100);
836                 }
837                 pconfig->nr_blocks = (size >> huge_page_shift(h));
838         }
839
840         return 0;
841
842 bad_val:
843         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
844                args[0].from, p);
845         return 1;
846 }
847
848 static int
849 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
850 {
851         struct inode * inode;
852         struct dentry * root;
853         int ret;
854         struct hugetlbfs_config config;
855         struct hugetlbfs_sb_info *sbinfo;
856
857         save_mount_options(sb, data);
858
859         config.nr_blocks = -1; /* No limit on size by default */
860         config.nr_inodes = -1; /* No limit on number of inodes by default */
861         config.uid = current_fsuid();
862         config.gid = current_fsgid();
863         config.mode = 0755;
864         config.hstate = &default_hstate;
865         ret = hugetlbfs_parse_options(data, &config);
866         if (ret)
867                 return ret;
868
869         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
870         if (!sbinfo)
871                 return -ENOMEM;
872         sb->s_fs_info = sbinfo;
873         sbinfo->hstate = config.hstate;
874         spin_lock_init(&sbinfo->stat_lock);
875         sbinfo->max_blocks = config.nr_blocks;
876         sbinfo->free_blocks = config.nr_blocks;
877         sbinfo->max_inodes = config.nr_inodes;
878         sbinfo->free_inodes = config.nr_inodes;
879         sb->s_maxbytes = MAX_LFS_FILESIZE;
880         sb->s_blocksize = huge_page_size(config.hstate);
881         sb->s_blocksize_bits = huge_page_shift(config.hstate);
882         sb->s_magic = HUGETLBFS_MAGIC;
883         sb->s_op = &hugetlbfs_ops;
884         sb->s_time_gran = 1;
885         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
886                                         S_IFDIR | config.mode, 0);
887         if (!inode)
888                 goto out_free;
889
890         root = d_alloc_root(inode);
891         if (!root) {
892                 iput(inode);
893                 goto out_free;
894         }
895         sb->s_root = root;
896         return 0;
897 out_free:
898         kfree(sbinfo);
899         return -ENOMEM;
900 }
901
902 int hugetlb_get_quota(struct address_space *mapping, long delta)
903 {
904         int ret = 0;
905         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
906
907         if (sbinfo->free_blocks > -1) {
908                 spin_lock(&sbinfo->stat_lock);
909                 if (sbinfo->free_blocks - delta >= 0)
910                         sbinfo->free_blocks -= delta;
911                 else
912                         ret = -ENOMEM;
913                 spin_unlock(&sbinfo->stat_lock);
914         }
915
916         return ret;
917 }
918
919 void hugetlb_put_quota(struct address_space *mapping, long delta)
920 {
921         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
922
923         if (sbinfo->free_blocks > -1) {
924                 spin_lock(&sbinfo->stat_lock);
925                 sbinfo->free_blocks += delta;
926                 spin_unlock(&sbinfo->stat_lock);
927         }
928 }
929
930 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
931         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
932 {
933         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
934 }
935
936 static struct file_system_type hugetlbfs_fs_type = {
937         .name           = "hugetlbfs",
938         .get_sb         = hugetlbfs_get_sb,
939         .kill_sb        = kill_litter_super,
940 };
941
942 static struct vfsmount *hugetlbfs_vfsmount;
943
944 static int can_do_hugetlb_shm(void)
945 {
946         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
947 }
948
949 struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag)
950 {
951         int error = -ENOMEM;
952         struct file *file;
953         struct inode *inode;
954         struct dentry *dentry, *root;
955         struct qstr quick_string;
956         struct user_struct *user = current_user();
957
958         if (!hugetlbfs_vfsmount)
959                 return ERR_PTR(-ENOENT);
960
961         if (!can_do_hugetlb_shm())
962                 return ERR_PTR(-EPERM);
963
964         root = hugetlbfs_vfsmount->mnt_root;
965         quick_string.name = name;
966         quick_string.len = strlen(quick_string.name);
967         quick_string.hash = 0;
968         dentry = d_alloc(root, &quick_string);
969         if (!dentry)
970                 goto out_shm_unlock;
971
972         error = -ENOSPC;
973         inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
974                                 current_fsgid(), S_IFREG | S_IRWXUGO, 0);
975         if (!inode)
976                 goto out_dentry;
977
978         error = -ENOMEM;
979         if (hugetlb_reserve_pages(inode, 0,
980                         size >> huge_page_shift(hstate_inode(inode)), NULL,
981                         acctflag))
982                 goto out_inode;
983
984         d_instantiate(dentry, inode);
985         inode->i_size = size;
986         inode->i_nlink = 0;
987
988         error = -ENFILE;
989         file = alloc_file(hugetlbfs_vfsmount, dentry,
990                         FMODE_WRITE | FMODE_READ,
991                         &hugetlbfs_file_operations);
992         if (!file)
993                 goto out_dentry; /* inode is already attached */
994
995         return file;
996
997 out_inode:
998         iput(inode);
999 out_dentry:
1000         dput(dentry);
1001 out_shm_unlock:
1002         return ERR_PTR(error);
1003 }
1004
1005 static int __init init_hugetlbfs_fs(void)
1006 {
1007         int error;
1008         struct vfsmount *vfsmount;
1009
1010         error = bdi_init(&hugetlbfs_backing_dev_info);
1011         if (error)
1012                 return error;
1013
1014         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1015                                         sizeof(struct hugetlbfs_inode_info),
1016                                         0, 0, init_once);
1017         if (hugetlbfs_inode_cachep == NULL)
1018                 goto out2;
1019
1020         error = register_filesystem(&hugetlbfs_fs_type);
1021         if (error)
1022                 goto out;
1023
1024         vfsmount = kern_mount(&hugetlbfs_fs_type);
1025
1026         if (!IS_ERR(vfsmount)) {
1027                 hugetlbfs_vfsmount = vfsmount;
1028                 return 0;
1029         }
1030
1031         error = PTR_ERR(vfsmount);
1032
1033  out:
1034         if (error)
1035                 kmem_cache_destroy(hugetlbfs_inode_cachep);
1036  out2:
1037         bdi_destroy(&hugetlbfs_backing_dev_info);
1038         return error;
1039 }
1040
1041 static void __exit exit_hugetlbfs_fs(void)
1042 {
1043         kmem_cache_destroy(hugetlbfs_inode_cachep);
1044         unregister_filesystem(&hugetlbfs_fs_type);
1045         bdi_destroy(&hugetlbfs_backing_dev_info);
1046 }
1047
1048 module_init(init_hugetlbfs_fs)
1049 module_exit(exit_hugetlbfs_fs)
1050
1051 MODULE_LICENSE("GPL");