hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race
[sfrench/cifs-2.6.git] / fs / hugetlbfs / inode.c
1 /*
2  * hugetlbpage-backed filesystem.  Based on ramfs.
3  *
4  * Nadia Yvette Chambers, 2002
5  *
6  * Copyright (C) 2002 Linus Torvalds.
7  * License: GPL
8  */
9
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/thread_info.h>
13 #include <asm/current.h>
14 #include <linux/sched/signal.h>         /* remove ASAP */
15 #include <linux/falloc.h>
16 #include <linux/fs.h>
17 #include <linux/mount.h>
18 #include <linux/file.h>
19 #include <linux/kernel.h>
20 #include <linux/writeback.h>
21 #include <linux/pagemap.h>
22 #include <linux/highmem.h>
23 #include <linux/init.h>
24 #include <linux/string.h>
25 #include <linux/capability.h>
26 #include <linux/ctype.h>
27 #include <linux/backing-dev.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagevec.h>
30 #include <linux/parser.h>
31 #include <linux/mman.h>
32 #include <linux/slab.h>
33 #include <linux/dnotify.h>
34 #include <linux/statfs.h>
35 #include <linux/security.h>
36 #include <linux/magic.h>
37 #include <linux/migrate.h>
38 #include <linux/uio.h>
39
40 #include <linux/uaccess.h>
41
42 static const struct super_operations hugetlbfs_ops;
43 static const struct address_space_operations hugetlbfs_aops;
44 const struct file_operations hugetlbfs_file_operations;
45 static const struct inode_operations hugetlbfs_dir_inode_operations;
46 static const struct inode_operations hugetlbfs_inode_operations;
47
48 struct hugetlbfs_config {
49         struct hstate           *hstate;
50         long                    max_hpages;
51         long                    nr_inodes;
52         long                    min_hpages;
53         kuid_t                  uid;
54         kgid_t                  gid;
55         umode_t                 mode;
56 };
57
58 int sysctl_hugetlb_shm_group;
59
60 enum {
61         Opt_size, Opt_nr_inodes,
62         Opt_mode, Opt_uid, Opt_gid,
63         Opt_pagesize, Opt_min_size,
64         Opt_err,
65 };
66
67 static const match_table_t tokens = {
68         {Opt_size,      "size=%s"},
69         {Opt_nr_inodes, "nr_inodes=%s"},
70         {Opt_mode,      "mode=%o"},
71         {Opt_uid,       "uid=%u"},
72         {Opt_gid,       "gid=%u"},
73         {Opt_pagesize,  "pagesize=%s"},
74         {Opt_min_size,  "min_size=%s"},
75         {Opt_err,       NULL},
76 };
77
78 #ifdef CONFIG_NUMA
79 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
80                                         struct inode *inode, pgoff_t index)
81 {
82         vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
83                                                         index);
84 }
85
86 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
87 {
88         mpol_cond_put(vma->vm_policy);
89 }
90 #else
91 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
92                                         struct inode *inode, pgoff_t index)
93 {
94 }
95
96 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
97 {
98 }
99 #endif
100
101 static void huge_pagevec_release(struct pagevec *pvec)
102 {
103         int i;
104
105         for (i = 0; i < pagevec_count(pvec); ++i)
106                 put_page(pvec->pages[i]);
107
108         pagevec_reinit(pvec);
109 }
110
111 /*
112  * Mask used when checking the page offset value passed in via system
113  * calls.  This value will be converted to a loff_t which is signed.
114  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
115  * value.  The extra bit (- 1 in the shift value) is to take the sign
116  * bit into account.
117  */
118 #define PGOFF_LOFFT_MAX \
119         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
120
121 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
122 {
123         struct inode *inode = file_inode(file);
124         loff_t len, vma_len;
125         int ret;
126         struct hstate *h = hstate_file(file);
127
128         /*
129          * vma address alignment (but not the pgoff alignment) has
130          * already been checked by prepare_hugepage_range.  If you add
131          * any error returns here, do so after setting VM_HUGETLB, so
132          * is_vm_hugetlb_page tests below unmap_region go the right
133          * way when do_mmap_pgoff unwinds (may be important on powerpc
134          * and ia64).
135          */
136         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
137         vma->vm_ops = &hugetlb_vm_ops;
138
139         /*
140          * page based offset in vm_pgoff could be sufficiently large to
141          * overflow a loff_t when converted to byte offset.  This can
142          * only happen on architectures where sizeof(loff_t) ==
143          * sizeof(unsigned long).  So, only check in those instances.
144          */
145         if (sizeof(unsigned long) == sizeof(loff_t)) {
146                 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
147                         return -EINVAL;
148         }
149
150         /* must be huge page aligned */
151         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
152                 return -EINVAL;
153
154         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
155         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
156         /* check for overflow */
157         if (len < vma_len)
158                 return -EINVAL;
159
160         inode_lock(inode);
161         file_accessed(file);
162
163         ret = -ENOMEM;
164         if (hugetlb_reserve_pages(inode,
165                                 vma->vm_pgoff >> huge_page_order(h),
166                                 len >> huge_page_shift(h), vma,
167                                 vma->vm_flags))
168                 goto out;
169
170         ret = 0;
171         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
172                 i_size_write(inode, len);
173 out:
174         inode_unlock(inode);
175
176         return ret;
177 }
178
179 /*
180  * Called under down_write(mmap_sem).
181  */
182
183 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
184 static unsigned long
185 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
186                 unsigned long len, unsigned long pgoff, unsigned long flags)
187 {
188         struct mm_struct *mm = current->mm;
189         struct vm_area_struct *vma;
190         struct hstate *h = hstate_file(file);
191         struct vm_unmapped_area_info info;
192
193         if (len & ~huge_page_mask(h))
194                 return -EINVAL;
195         if (len > TASK_SIZE)
196                 return -ENOMEM;
197
198         if (flags & MAP_FIXED) {
199                 if (prepare_hugepage_range(file, addr, len))
200                         return -EINVAL;
201                 return addr;
202         }
203
204         if (addr) {
205                 addr = ALIGN(addr, huge_page_size(h));
206                 vma = find_vma(mm, addr);
207                 if (TASK_SIZE - len >= addr &&
208                     (!vma || addr + len <= vm_start_gap(vma)))
209                         return addr;
210         }
211
212         info.flags = 0;
213         info.length = len;
214         info.low_limit = TASK_UNMAPPED_BASE;
215         info.high_limit = TASK_SIZE;
216         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
217         info.align_offset = 0;
218         return vm_unmapped_area(&info);
219 }
220 #endif
221
222 static size_t
223 hugetlbfs_read_actor(struct page *page, unsigned long offset,
224                         struct iov_iter *to, unsigned long size)
225 {
226         size_t copied = 0;
227         int i, chunksize;
228
229         /* Find which 4k chunk and offset with in that chunk */
230         i = offset >> PAGE_SHIFT;
231         offset = offset & ~PAGE_MASK;
232
233         while (size) {
234                 size_t n;
235                 chunksize = PAGE_SIZE;
236                 if (offset)
237                         chunksize -= offset;
238                 if (chunksize > size)
239                         chunksize = size;
240                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
241                 copied += n;
242                 if (n != chunksize)
243                         return copied;
244                 offset = 0;
245                 size -= chunksize;
246                 i++;
247         }
248         return copied;
249 }
250
251 /*
252  * Support for read() - Find the page attached to f_mapping and copy out the
253  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
254  * since it has PAGE_SIZE assumptions.
255  */
256 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
257 {
258         struct file *file = iocb->ki_filp;
259         struct hstate *h = hstate_file(file);
260         struct address_space *mapping = file->f_mapping;
261         struct inode *inode = mapping->host;
262         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
263         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
264         unsigned long end_index;
265         loff_t isize;
266         ssize_t retval = 0;
267
268         while (iov_iter_count(to)) {
269                 struct page *page;
270                 size_t nr, copied;
271
272                 /* nr is the maximum number of bytes to copy from this page */
273                 nr = huge_page_size(h);
274                 isize = i_size_read(inode);
275                 if (!isize)
276                         break;
277                 end_index = (isize - 1) >> huge_page_shift(h);
278                 if (index > end_index)
279                         break;
280                 if (index == end_index) {
281                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
282                         if (nr <= offset)
283                                 break;
284                 }
285                 nr = nr - offset;
286
287                 /* Find the page */
288                 page = find_lock_page(mapping, index);
289                 if (unlikely(page == NULL)) {
290                         /*
291                          * We have a HOLE, zero out the user-buffer for the
292                          * length of the hole or request.
293                          */
294                         copied = iov_iter_zero(nr, to);
295                 } else {
296                         unlock_page(page);
297
298                         /*
299                          * We have the page, copy it to user space buffer.
300                          */
301                         copied = hugetlbfs_read_actor(page, offset, to, nr);
302                         put_page(page);
303                 }
304                 offset += copied;
305                 retval += copied;
306                 if (copied != nr && iov_iter_count(to)) {
307                         if (!retval)
308                                 retval = -EFAULT;
309                         break;
310                 }
311                 index += offset >> huge_page_shift(h);
312                 offset &= ~huge_page_mask(h);
313         }
314         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
315         return retval;
316 }
317
318 static int hugetlbfs_write_begin(struct file *file,
319                         struct address_space *mapping,
320                         loff_t pos, unsigned len, unsigned flags,
321                         struct page **pagep, void **fsdata)
322 {
323         return -EINVAL;
324 }
325
326 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
327                         loff_t pos, unsigned len, unsigned copied,
328                         struct page *page, void *fsdata)
329 {
330         BUG();
331         return -EINVAL;
332 }
333
334 static void remove_huge_page(struct page *page)
335 {
336         ClearPageDirty(page);
337         ClearPageUptodate(page);
338         delete_from_page_cache(page);
339 }
340
341 static void
342 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end)
343 {
344         struct vm_area_struct *vma;
345
346         /*
347          * end == 0 indicates that the entire range after
348          * start should be unmapped.
349          */
350         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
351                 unsigned long v_offset;
352                 unsigned long v_end;
353
354                 /*
355                  * Can the expression below overflow on 32-bit arches?
356                  * No, because the interval tree returns us only those vmas
357                  * which overlap the truncated area starting at pgoff,
358                  * and no vma on a 32-bit arch can span beyond the 4GB.
359                  */
360                 if (vma->vm_pgoff < start)
361                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
362                 else
363                         v_offset = 0;
364
365                 if (!end)
366                         v_end = vma->vm_end;
367                 else {
368                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
369                                                         + vma->vm_start;
370                         if (v_end > vma->vm_end)
371                                 v_end = vma->vm_end;
372                 }
373
374                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
375                                                                         NULL);
376         }
377 }
378
379 /*
380  * remove_inode_hugepages handles two distinct cases: truncation and hole
381  * punch.  There are subtle differences in operation for each case.
382  *
383  * truncation is indicated by end of range being LLONG_MAX
384  *      In this case, we first scan the range and release found pages.
385  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
386  *      maps and global counts.
387  * hole punch is indicated if end is not LLONG_MAX
388  *      In the hole punch case we scan the range and release found pages.
389  *      Only when releasing a page is the associated region/reserv map
390  *      deleted.  The region/reserv map for ranges without associated
391  *      pages are not modified.
392  *
393  * Callers of this routine must hold the i_mmap_rwsem in write mode to prevent
394  * races with page faults.
395  *
396  * Note: If the passed end of range value is beyond the end of file, but
397  * not LLONG_MAX this routine still performs a hole punch operation.
398  */
399 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
400                                    loff_t lend)
401 {
402         struct hstate *h = hstate_inode(inode);
403         struct address_space *mapping = &inode->i_data;
404         const pgoff_t start = lstart >> huge_page_shift(h);
405         const pgoff_t end = lend >> huge_page_shift(h);
406         struct vm_area_struct pseudo_vma;
407         struct pagevec pvec;
408         pgoff_t next, index;
409         int i, freed = 0;
410         bool truncate_op = (lend == LLONG_MAX);
411
412         vma_init(&pseudo_vma, current->mm);
413         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
414         pagevec_init(&pvec);
415         next = start;
416         while (next < end) {
417                 /*
418                  * When no more pages are found, we are done.
419                  */
420                 if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
421                         break;
422
423                 for (i = 0; i < pagevec_count(&pvec); ++i) {
424                         struct page *page = pvec.pages[i];
425
426                         index = page->index;
427                         /*
428                          * A mapped page is impossible as callers should unmap
429                          * all references before calling.  And, i_mmap_rwsem
430                          * prevents the creation of additional mappings.
431                          */
432                         VM_BUG_ON(page_mapped(page));
433
434                         lock_page(page);
435                         /*
436                          * We must free the huge page and remove from page
437                          * cache (remove_huge_page) BEFORE removing the
438                          * region/reserve map (hugetlb_unreserve_pages).  In
439                          * rare out of memory conditions, removal of the
440                          * region/reserve map could fail. Correspondingly,
441                          * the subpool and global reserve usage count can need
442                          * to be adjusted.
443                          */
444                         VM_BUG_ON(PagePrivate(page));
445                         remove_huge_page(page);
446                         freed++;
447                         if (!truncate_op) {
448                                 if (unlikely(hugetlb_unreserve_pages(inode,
449                                                         index, index + 1, 1)))
450                                         hugetlb_fix_reserve_counts(inode);
451                         }
452
453                         unlock_page(page);
454                 }
455                 huge_pagevec_release(&pvec);
456                 cond_resched();
457         }
458
459         if (truncate_op)
460                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
461 }
462
463 static void hugetlbfs_evict_inode(struct inode *inode)
464 {
465         struct address_space *mapping = inode->i_mapping;
466         struct resv_map *resv_map;
467
468         /*
469          * The vfs layer guarantees that there are no other users of this
470          * inode.  Therefore, it would be safe to call remove_inode_hugepages
471          * without holding i_mmap_rwsem.  We acquire and hold here to be
472          * consistent with other callers.  Since there will be no contention
473          * on the semaphore, overhead is negligible.
474          */
475         i_mmap_lock_write(mapping);
476         remove_inode_hugepages(inode, 0, LLONG_MAX);
477         i_mmap_unlock_write(mapping);
478
479         resv_map = (struct resv_map *)inode->i_mapping->private_data;
480         /* root inode doesn't have the resv_map, so we should check it */
481         if (resv_map)
482                 resv_map_release(&resv_map->refs);
483         clear_inode(inode);
484 }
485
486 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
487 {
488         pgoff_t pgoff;
489         struct address_space *mapping = inode->i_mapping;
490         struct hstate *h = hstate_inode(inode);
491
492         BUG_ON(offset & ~huge_page_mask(h));
493         pgoff = offset >> PAGE_SHIFT;
494
495         i_size_write(inode, offset);
496         i_mmap_lock_write(mapping);
497         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
498                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
499         remove_inode_hugepages(inode, offset, LLONG_MAX);
500         i_mmap_unlock_write(mapping);
501         return 0;
502 }
503
504 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
505 {
506         struct hstate *h = hstate_inode(inode);
507         loff_t hpage_size = huge_page_size(h);
508         loff_t hole_start, hole_end;
509
510         /*
511          * For hole punch round up the beginning offset of the hole and
512          * round down the end.
513          */
514         hole_start = round_up(offset, hpage_size);
515         hole_end = round_down(offset + len, hpage_size);
516
517         if (hole_end > hole_start) {
518                 struct address_space *mapping = inode->i_mapping;
519                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
520
521                 inode_lock(inode);
522
523                 /* protected by i_mutex */
524                 if (info->seals & F_SEAL_WRITE) {
525                         inode_unlock(inode);
526                         return -EPERM;
527                 }
528
529                 i_mmap_lock_write(mapping);
530                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
531                         hugetlb_vmdelete_list(&mapping->i_mmap,
532                                                 hole_start >> PAGE_SHIFT,
533                                                 hole_end  >> PAGE_SHIFT);
534                 remove_inode_hugepages(inode, hole_start, hole_end);
535                 i_mmap_unlock_write(mapping);
536                 inode_unlock(inode);
537         }
538
539         return 0;
540 }
541
542 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
543                                 loff_t len)
544 {
545         struct inode *inode = file_inode(file);
546         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
547         struct address_space *mapping = inode->i_mapping;
548         struct hstate *h = hstate_inode(inode);
549         struct vm_area_struct pseudo_vma;
550         struct mm_struct *mm = current->mm;
551         loff_t hpage_size = huge_page_size(h);
552         unsigned long hpage_shift = huge_page_shift(h);
553         pgoff_t start, index, end;
554         int error;
555         u32 hash;
556
557         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
558                 return -EOPNOTSUPP;
559
560         if (mode & FALLOC_FL_PUNCH_HOLE)
561                 return hugetlbfs_punch_hole(inode, offset, len);
562
563         /*
564          * Default preallocate case.
565          * For this range, start is rounded down and end is rounded up
566          * as well as being converted to page offsets.
567          */
568         start = offset >> hpage_shift;
569         end = (offset + len + hpage_size - 1) >> hpage_shift;
570
571         inode_lock(inode);
572
573         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
574         error = inode_newsize_ok(inode, offset + len);
575         if (error)
576                 goto out;
577
578         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
579                 error = -EPERM;
580                 goto out;
581         }
582
583         /*
584          * Initialize a pseudo vma as this is required by the huge page
585          * allocation routines.  If NUMA is configured, use page index
586          * as input to create an allocation policy.
587          */
588         vma_init(&pseudo_vma, mm);
589         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
590         pseudo_vma.vm_file = file;
591
592         for (index = start; index < end; index++) {
593                 /*
594                  * This is supposed to be the vaddr where the page is being
595                  * faulted in, but we have no vaddr here.
596                  */
597                 struct page *page;
598                 unsigned long addr;
599                 int avoid_reserve = 0;
600
601                 cond_resched();
602
603                 /*
604                  * fallocate(2) manpage permits EINTR; we may have been
605                  * interrupted because we are using up too much memory.
606                  */
607                 if (signal_pending(current)) {
608                         error = -EINTR;
609                         break;
610                 }
611
612                 /* Set numa allocation policy based on index */
613                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
614
615                 /* addr is the offset within the file (zero based) */
616                 addr = index * hpage_size;
617
618                 /*
619                  * fault mutex taken here, protects against fault path
620                  * and hole punch.  inode_lock previously taken protects
621                  * against truncation.
622                  */
623                 hash = hugetlb_fault_mutex_hash(h, mm, &pseudo_vma, mapping,
624                                                 index, addr);
625                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
626
627                 /* See if already present in mapping to avoid alloc/free */
628                 page = find_get_page(mapping, index);
629                 if (page) {
630                         put_page(page);
631                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
632                         hugetlb_drop_vma_policy(&pseudo_vma);
633                         continue;
634                 }
635
636                 /* Allocate page and add to page cache */
637                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
638                 hugetlb_drop_vma_policy(&pseudo_vma);
639                 if (IS_ERR(page)) {
640                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
641                         error = PTR_ERR(page);
642                         goto out;
643                 }
644                 clear_huge_page(page, addr, pages_per_huge_page(h));
645                 __SetPageUptodate(page);
646                 error = huge_add_to_page_cache(page, mapping, index);
647                 if (unlikely(error)) {
648                         put_page(page);
649                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
650                         goto out;
651                 }
652
653                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
654
655                 /*
656                  * unlock_page because locked by add_to_page_cache()
657                  * page_put due to reference from alloc_huge_page()
658                  */
659                 unlock_page(page);
660                 put_page(page);
661         }
662
663         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
664                 i_size_write(inode, offset + len);
665         inode->i_ctime = current_time(inode);
666 out:
667         inode_unlock(inode);
668         return error;
669 }
670
671 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
672 {
673         struct inode *inode = d_inode(dentry);
674         struct hstate *h = hstate_inode(inode);
675         int error;
676         unsigned int ia_valid = attr->ia_valid;
677         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
678
679         BUG_ON(!inode);
680
681         error = setattr_prepare(dentry, attr);
682         if (error)
683                 return error;
684
685         if (ia_valid & ATTR_SIZE) {
686                 loff_t oldsize = inode->i_size;
687                 loff_t newsize = attr->ia_size;
688
689                 if (newsize & ~huge_page_mask(h))
690                         return -EINVAL;
691                 /* protected by i_mutex */
692                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
693                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
694                         return -EPERM;
695                 error = hugetlb_vmtruncate(inode, newsize);
696                 if (error)
697                         return error;
698         }
699
700         setattr_copy(inode, attr);
701         mark_inode_dirty(inode);
702         return 0;
703 }
704
705 static struct inode *hugetlbfs_get_root(struct super_block *sb,
706                                         struct hugetlbfs_config *config)
707 {
708         struct inode *inode;
709
710         inode = new_inode(sb);
711         if (inode) {
712                 inode->i_ino = get_next_ino();
713                 inode->i_mode = S_IFDIR | config->mode;
714                 inode->i_uid = config->uid;
715                 inode->i_gid = config->gid;
716                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
717                 inode->i_op = &hugetlbfs_dir_inode_operations;
718                 inode->i_fop = &simple_dir_operations;
719                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
720                 inc_nlink(inode);
721                 lockdep_annotate_inode_mutex_key(inode);
722         }
723         return inode;
724 }
725
726 /*
727  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
728  * be taken from reclaim -- unlike regular filesystems. This needs an
729  * annotation because huge_pmd_share() does an allocation under hugetlb's
730  * i_mmap_rwsem.
731  */
732 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
733
734 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
735                                         struct inode *dir,
736                                         umode_t mode, dev_t dev)
737 {
738         struct inode *inode;
739         struct resv_map *resv_map;
740
741         resv_map = resv_map_alloc();
742         if (!resv_map)
743                 return NULL;
744
745         inode = new_inode(sb);
746         if (inode) {
747                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
748
749                 inode->i_ino = get_next_ino();
750                 inode_init_owner(inode, dir, mode);
751                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
752                                 &hugetlbfs_i_mmap_rwsem_key);
753                 inode->i_mapping->a_ops = &hugetlbfs_aops;
754                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
755                 inode->i_mapping->private_data = resv_map;
756                 info->seals = F_SEAL_SEAL;
757                 switch (mode & S_IFMT) {
758                 default:
759                         init_special_inode(inode, mode, dev);
760                         break;
761                 case S_IFREG:
762                         inode->i_op = &hugetlbfs_inode_operations;
763                         inode->i_fop = &hugetlbfs_file_operations;
764                         break;
765                 case S_IFDIR:
766                         inode->i_op = &hugetlbfs_dir_inode_operations;
767                         inode->i_fop = &simple_dir_operations;
768
769                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
770                         inc_nlink(inode);
771                         break;
772                 case S_IFLNK:
773                         inode->i_op = &page_symlink_inode_operations;
774                         inode_nohighmem(inode);
775                         break;
776                 }
777                 lockdep_annotate_inode_mutex_key(inode);
778         } else
779                 kref_put(&resv_map->refs, resv_map_release);
780
781         return inode;
782 }
783
784 /*
785  * File creation. Allocate an inode, and we're done..
786  */
787 static int hugetlbfs_mknod(struct inode *dir,
788                         struct dentry *dentry, umode_t mode, dev_t dev)
789 {
790         struct inode *inode;
791         int error = -ENOSPC;
792
793         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
794         if (inode) {
795                 dir->i_ctime = dir->i_mtime = current_time(dir);
796                 d_instantiate(dentry, inode);
797                 dget(dentry);   /* Extra count - pin the dentry in core */
798                 error = 0;
799         }
800         return error;
801 }
802
803 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
804 {
805         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
806         if (!retval)
807                 inc_nlink(dir);
808         return retval;
809 }
810
811 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
812 {
813         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
814 }
815
816 static int hugetlbfs_symlink(struct inode *dir,
817                         struct dentry *dentry, const char *symname)
818 {
819         struct inode *inode;
820         int error = -ENOSPC;
821
822         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
823         if (inode) {
824                 int l = strlen(symname)+1;
825                 error = page_symlink(inode, symname, l);
826                 if (!error) {
827                         d_instantiate(dentry, inode);
828                         dget(dentry);
829                 } else
830                         iput(inode);
831         }
832         dir->i_ctime = dir->i_mtime = current_time(dir);
833
834         return error;
835 }
836
837 /*
838  * mark the head page dirty
839  */
840 static int hugetlbfs_set_page_dirty(struct page *page)
841 {
842         struct page *head = compound_head(page);
843
844         SetPageDirty(head);
845         return 0;
846 }
847
848 static int hugetlbfs_migrate_page(struct address_space *mapping,
849                                 struct page *newpage, struct page *page,
850                                 enum migrate_mode mode)
851 {
852         int rc;
853
854         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
855         if (rc != MIGRATEPAGE_SUCCESS)
856                 return rc;
857         if (mode != MIGRATE_SYNC_NO_COPY)
858                 migrate_page_copy(newpage, page);
859         else
860                 migrate_page_states(newpage, page);
861
862         return MIGRATEPAGE_SUCCESS;
863 }
864
865 static int hugetlbfs_error_remove_page(struct address_space *mapping,
866                                 struct page *page)
867 {
868         struct inode *inode = mapping->host;
869         pgoff_t index = page->index;
870
871         remove_huge_page(page);
872         if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
873                 hugetlb_fix_reserve_counts(inode);
874
875         return 0;
876 }
877
878 /*
879  * Display the mount options in /proc/mounts.
880  */
881 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
882 {
883         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
884         struct hugepage_subpool *spool = sbinfo->spool;
885         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
886         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
887         char mod;
888
889         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
890                 seq_printf(m, ",uid=%u",
891                            from_kuid_munged(&init_user_ns, sbinfo->uid));
892         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
893                 seq_printf(m, ",gid=%u",
894                            from_kgid_munged(&init_user_ns, sbinfo->gid));
895         if (sbinfo->mode != 0755)
896                 seq_printf(m, ",mode=%o", sbinfo->mode);
897         if (sbinfo->max_inodes != -1)
898                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
899
900         hpage_size /= 1024;
901         mod = 'K';
902         if (hpage_size >= 1024) {
903                 hpage_size /= 1024;
904                 mod = 'M';
905         }
906         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
907         if (spool) {
908                 if (spool->max_hpages != -1)
909                         seq_printf(m, ",size=%llu",
910                                    (unsigned long long)spool->max_hpages << hpage_shift);
911                 if (spool->min_hpages != -1)
912                         seq_printf(m, ",min_size=%llu",
913                                    (unsigned long long)spool->min_hpages << hpage_shift);
914         }
915         return 0;
916 }
917
918 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
919 {
920         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
921         struct hstate *h = hstate_inode(d_inode(dentry));
922
923         buf->f_type = HUGETLBFS_MAGIC;
924         buf->f_bsize = huge_page_size(h);
925         if (sbinfo) {
926                 spin_lock(&sbinfo->stat_lock);
927                 /* If no limits set, just report 0 for max/free/used
928                  * blocks, like simple_statfs() */
929                 if (sbinfo->spool) {
930                         long free_pages;
931
932                         spin_lock(&sbinfo->spool->lock);
933                         buf->f_blocks = sbinfo->spool->max_hpages;
934                         free_pages = sbinfo->spool->max_hpages
935                                 - sbinfo->spool->used_hpages;
936                         buf->f_bavail = buf->f_bfree = free_pages;
937                         spin_unlock(&sbinfo->spool->lock);
938                         buf->f_files = sbinfo->max_inodes;
939                         buf->f_ffree = sbinfo->free_inodes;
940                 }
941                 spin_unlock(&sbinfo->stat_lock);
942         }
943         buf->f_namelen = NAME_MAX;
944         return 0;
945 }
946
947 static void hugetlbfs_put_super(struct super_block *sb)
948 {
949         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
950
951         if (sbi) {
952                 sb->s_fs_info = NULL;
953
954                 if (sbi->spool)
955                         hugepage_put_subpool(sbi->spool);
956
957                 kfree(sbi);
958         }
959 }
960
961 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
962 {
963         if (sbinfo->free_inodes >= 0) {
964                 spin_lock(&sbinfo->stat_lock);
965                 if (unlikely(!sbinfo->free_inodes)) {
966                         spin_unlock(&sbinfo->stat_lock);
967                         return 0;
968                 }
969                 sbinfo->free_inodes--;
970                 spin_unlock(&sbinfo->stat_lock);
971         }
972
973         return 1;
974 }
975
976 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
977 {
978         if (sbinfo->free_inodes >= 0) {
979                 spin_lock(&sbinfo->stat_lock);
980                 sbinfo->free_inodes++;
981                 spin_unlock(&sbinfo->stat_lock);
982         }
983 }
984
985
986 static struct kmem_cache *hugetlbfs_inode_cachep;
987
988 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
989 {
990         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
991         struct hugetlbfs_inode_info *p;
992
993         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
994                 return NULL;
995         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
996         if (unlikely(!p)) {
997                 hugetlbfs_inc_free_inodes(sbinfo);
998                 return NULL;
999         }
1000
1001         /*
1002          * Any time after allocation, hugetlbfs_destroy_inode can be called
1003          * for the inode.  mpol_free_shared_policy is unconditionally called
1004          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
1005          * in case of a quick call to destroy.
1006          *
1007          * Note that the policy is initialized even if we are creating a
1008          * private inode.  This simplifies hugetlbfs_destroy_inode.
1009          */
1010         mpol_shared_policy_init(&p->policy, NULL);
1011
1012         return &p->vfs_inode;
1013 }
1014
1015 static void hugetlbfs_i_callback(struct rcu_head *head)
1016 {
1017         struct inode *inode = container_of(head, struct inode, i_rcu);
1018         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1019 }
1020
1021 static void hugetlbfs_destroy_inode(struct inode *inode)
1022 {
1023         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1024         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1025         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
1026 }
1027
1028 static const struct address_space_operations hugetlbfs_aops = {
1029         .write_begin    = hugetlbfs_write_begin,
1030         .write_end      = hugetlbfs_write_end,
1031         .set_page_dirty = hugetlbfs_set_page_dirty,
1032         .migratepage    = hugetlbfs_migrate_page,
1033         .error_remove_page      = hugetlbfs_error_remove_page,
1034 };
1035
1036
1037 static void init_once(void *foo)
1038 {
1039         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1040
1041         inode_init_once(&ei->vfs_inode);
1042 }
1043
1044 const struct file_operations hugetlbfs_file_operations = {
1045         .read_iter              = hugetlbfs_read_iter,
1046         .mmap                   = hugetlbfs_file_mmap,
1047         .fsync                  = noop_fsync,
1048         .get_unmapped_area      = hugetlb_get_unmapped_area,
1049         .llseek                 = default_llseek,
1050         .fallocate              = hugetlbfs_fallocate,
1051 };
1052
1053 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1054         .create         = hugetlbfs_create,
1055         .lookup         = simple_lookup,
1056         .link           = simple_link,
1057         .unlink         = simple_unlink,
1058         .symlink        = hugetlbfs_symlink,
1059         .mkdir          = hugetlbfs_mkdir,
1060         .rmdir          = simple_rmdir,
1061         .mknod          = hugetlbfs_mknod,
1062         .rename         = simple_rename,
1063         .setattr        = hugetlbfs_setattr,
1064 };
1065
1066 static const struct inode_operations hugetlbfs_inode_operations = {
1067         .setattr        = hugetlbfs_setattr,
1068 };
1069
1070 static const struct super_operations hugetlbfs_ops = {
1071         .alloc_inode    = hugetlbfs_alloc_inode,
1072         .destroy_inode  = hugetlbfs_destroy_inode,
1073         .evict_inode    = hugetlbfs_evict_inode,
1074         .statfs         = hugetlbfs_statfs,
1075         .put_super      = hugetlbfs_put_super,
1076         .show_options   = hugetlbfs_show_options,
1077 };
1078
1079 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
1080
1081 /*
1082  * Convert size option passed from command line to number of huge pages
1083  * in the pool specified by hstate.  Size option could be in bytes
1084  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1085  */
1086 static long
1087 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1088                          enum hugetlbfs_size_type val_type)
1089 {
1090         if (val_type == NO_SIZE)
1091                 return -1;
1092
1093         if (val_type == SIZE_PERCENT) {
1094                 size_opt <<= huge_page_shift(h);
1095                 size_opt *= h->max_huge_pages;
1096                 do_div(size_opt, 100);
1097         }
1098
1099         size_opt >>= huge_page_shift(h);
1100         return size_opt;
1101 }
1102
1103 static int
1104 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
1105 {
1106         char *p, *rest;
1107         substring_t args[MAX_OPT_ARGS];
1108         int option;
1109         unsigned long long max_size_opt = 0, min_size_opt = 0;
1110         enum hugetlbfs_size_type max_val_type = NO_SIZE, min_val_type = NO_SIZE;
1111
1112         if (!options)
1113                 return 0;
1114
1115         while ((p = strsep(&options, ",")) != NULL) {
1116                 int token;
1117                 if (!*p)
1118                         continue;
1119
1120                 token = match_token(p, tokens, args);
1121                 switch (token) {
1122                 case Opt_uid:
1123                         if (match_int(&args[0], &option))
1124                                 goto bad_val;
1125                         pconfig->uid = make_kuid(current_user_ns(), option);
1126                         if (!uid_valid(pconfig->uid))
1127                                 goto bad_val;
1128                         break;
1129
1130                 case Opt_gid:
1131                         if (match_int(&args[0], &option))
1132                                 goto bad_val;
1133                         pconfig->gid = make_kgid(current_user_ns(), option);
1134                         if (!gid_valid(pconfig->gid))
1135                                 goto bad_val;
1136                         break;
1137
1138                 case Opt_mode:
1139                         if (match_octal(&args[0], &option))
1140                                 goto bad_val;
1141                         pconfig->mode = option & 01777U;
1142                         break;
1143
1144                 case Opt_size: {
1145                         /* memparse() will accept a K/M/G without a digit */
1146                         if (!isdigit(*args[0].from))
1147                                 goto bad_val;
1148                         max_size_opt = memparse(args[0].from, &rest);
1149                         max_val_type = SIZE_STD;
1150                         if (*rest == '%')
1151                                 max_val_type = SIZE_PERCENT;
1152                         break;
1153                 }
1154
1155                 case Opt_nr_inodes:
1156                         /* memparse() will accept a K/M/G without a digit */
1157                         if (!isdigit(*args[0].from))
1158                                 goto bad_val;
1159                         pconfig->nr_inodes = memparse(args[0].from, &rest);
1160                         break;
1161
1162                 case Opt_pagesize: {
1163                         unsigned long ps;
1164                         ps = memparse(args[0].from, &rest);
1165                         pconfig->hstate = size_to_hstate(ps);
1166                         if (!pconfig->hstate) {
1167                                 pr_err("Unsupported page size %lu MB\n",
1168                                         ps >> 20);
1169                                 return -EINVAL;
1170                         }
1171                         break;
1172                 }
1173
1174                 case Opt_min_size: {
1175                         /* memparse() will accept a K/M/G without a digit */
1176                         if (!isdigit(*args[0].from))
1177                                 goto bad_val;
1178                         min_size_opt = memparse(args[0].from, &rest);
1179                         min_val_type = SIZE_STD;
1180                         if (*rest == '%')
1181                                 min_val_type = SIZE_PERCENT;
1182                         break;
1183                 }
1184
1185                 default:
1186                         pr_err("Bad mount option: \"%s\"\n", p);
1187                         return -EINVAL;
1188                         break;
1189                 }
1190         }
1191
1192         /*
1193          * Use huge page pool size (in hstate) to convert the size
1194          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1195          */
1196         pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1197                                                 max_size_opt, max_val_type);
1198         pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1199                                                 min_size_opt, min_val_type);
1200
1201         /*
1202          * If max_size was specified, then min_size must be smaller
1203          */
1204         if (max_val_type > NO_SIZE &&
1205             pconfig->min_hpages > pconfig->max_hpages) {
1206                 pr_err("minimum size can not be greater than maximum size\n");
1207                 return -EINVAL;
1208         }
1209
1210         return 0;
1211
1212 bad_val:
1213         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
1214         return -EINVAL;
1215 }
1216
1217 static int
1218 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
1219 {
1220         int ret;
1221         struct hugetlbfs_config config;
1222         struct hugetlbfs_sb_info *sbinfo;
1223
1224         config.max_hpages = -1; /* No limit on size by default */
1225         config.nr_inodes = -1; /* No limit on number of inodes by default */
1226         config.uid = current_fsuid();
1227         config.gid = current_fsgid();
1228         config.mode = 0755;
1229         config.hstate = &default_hstate;
1230         config.min_hpages = -1; /* No default minimum size */
1231         ret = hugetlbfs_parse_options(data, &config);
1232         if (ret)
1233                 return ret;
1234
1235         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1236         if (!sbinfo)
1237                 return -ENOMEM;
1238         sb->s_fs_info = sbinfo;
1239         sbinfo->hstate = config.hstate;
1240         spin_lock_init(&sbinfo->stat_lock);
1241         sbinfo->max_inodes = config.nr_inodes;
1242         sbinfo->free_inodes = config.nr_inodes;
1243         sbinfo->spool = NULL;
1244         sbinfo->uid = config.uid;
1245         sbinfo->gid = config.gid;
1246         sbinfo->mode = config.mode;
1247
1248         /*
1249          * Allocate and initialize subpool if maximum or minimum size is
1250          * specified.  Any needed reservations (for minimim size) are taken
1251          * taken when the subpool is created.
1252          */
1253         if (config.max_hpages != -1 || config.min_hpages != -1) {
1254                 sbinfo->spool = hugepage_new_subpool(config.hstate,
1255                                                         config.max_hpages,
1256                                                         config.min_hpages);
1257                 if (!sbinfo->spool)
1258                         goto out_free;
1259         }
1260         sb->s_maxbytes = MAX_LFS_FILESIZE;
1261         sb->s_blocksize = huge_page_size(config.hstate);
1262         sb->s_blocksize_bits = huge_page_shift(config.hstate);
1263         sb->s_magic = HUGETLBFS_MAGIC;
1264         sb->s_op = &hugetlbfs_ops;
1265         sb->s_time_gran = 1;
1266         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
1267         if (!sb->s_root)
1268                 goto out_free;
1269         return 0;
1270 out_free:
1271         kfree(sbinfo->spool);
1272         kfree(sbinfo);
1273         return -ENOMEM;
1274 }
1275
1276 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
1277         int flags, const char *dev_name, void *data)
1278 {
1279         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
1280 }
1281
1282 static struct file_system_type hugetlbfs_fs_type = {
1283         .name           = "hugetlbfs",
1284         .mount          = hugetlbfs_mount,
1285         .kill_sb        = kill_litter_super,
1286 };
1287
1288 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1289
1290 static int can_do_hugetlb_shm(void)
1291 {
1292         kgid_t shm_group;
1293         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1294         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1295 }
1296
1297 static int get_hstate_idx(int page_size_log)
1298 {
1299         struct hstate *h = hstate_sizelog(page_size_log);
1300
1301         if (!h)
1302                 return -1;
1303         return h - hstates;
1304 }
1305
1306 /*
1307  * Note that size should be aligned to proper hugepage size in caller side,
1308  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1309  */
1310 struct file *hugetlb_file_setup(const char *name, size_t size,
1311                                 vm_flags_t acctflag, struct user_struct **user,
1312                                 int creat_flags, int page_size_log)
1313 {
1314         struct inode *inode;
1315         struct vfsmount *mnt;
1316         int hstate_idx;
1317         struct file *file;
1318
1319         hstate_idx = get_hstate_idx(page_size_log);
1320         if (hstate_idx < 0)
1321                 return ERR_PTR(-ENODEV);
1322
1323         *user = NULL;
1324         mnt = hugetlbfs_vfsmount[hstate_idx];
1325         if (!mnt)
1326                 return ERR_PTR(-ENOENT);
1327
1328         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1329                 *user = current_user();
1330                 if (user_shm_lock(size, *user)) {
1331                         task_lock(current);
1332                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1333                                 current->comm, current->pid);
1334                         task_unlock(current);
1335                 } else {
1336                         *user = NULL;
1337                         return ERR_PTR(-EPERM);
1338                 }
1339         }
1340
1341         file = ERR_PTR(-ENOSPC);
1342         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1343         if (!inode)
1344                 goto out;
1345         if (creat_flags == HUGETLB_SHMFS_INODE)
1346                 inode->i_flags |= S_PRIVATE;
1347
1348         inode->i_size = size;
1349         clear_nlink(inode);
1350
1351         if (hugetlb_reserve_pages(inode, 0,
1352                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1353                         acctflag))
1354                 file = ERR_PTR(-ENOMEM);
1355         else
1356                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1357                                         &hugetlbfs_file_operations);
1358         if (!IS_ERR(file))
1359                 return file;
1360
1361         iput(inode);
1362 out:
1363         if (*user) {
1364                 user_shm_unlock(size, *user);
1365                 *user = NULL;
1366         }
1367         return file;
1368 }
1369
1370 static int __init init_hugetlbfs_fs(void)
1371 {
1372         struct hstate *h;
1373         int error;
1374         int i;
1375
1376         if (!hugepages_supported()) {
1377                 pr_info("disabling because there are no supported hugepage sizes\n");
1378                 return -ENOTSUPP;
1379         }
1380
1381         error = -ENOMEM;
1382         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1383                                         sizeof(struct hugetlbfs_inode_info),
1384                                         0, SLAB_ACCOUNT, init_once);
1385         if (hugetlbfs_inode_cachep == NULL)
1386                 goto out2;
1387
1388         error = register_filesystem(&hugetlbfs_fs_type);
1389         if (error)
1390                 goto out;
1391
1392         i = 0;
1393         for_each_hstate(h) {
1394                 char buf[50];
1395                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1396
1397                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1398                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1399                                                         buf);
1400
1401                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1402                         pr_err("Cannot mount internal hugetlbfs for "
1403                                 "page size %uK", ps_kb);
1404                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1405                         hugetlbfs_vfsmount[i] = NULL;
1406                 }
1407                 i++;
1408         }
1409         /* Non default hstates are optional */
1410         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1411                 return 0;
1412
1413  out:
1414         kmem_cache_destroy(hugetlbfs_inode_cachep);
1415  out2:
1416         return error;
1417 }
1418 fs_initcall(init_hugetlbfs_fs)