Merge tag 'for-linus-5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-microblaze.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/fs_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 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
49
50 struct hugetlbfs_fs_context {
51         struct hstate           *hstate;
52         unsigned long long      max_size_opt;
53         unsigned long long      min_size_opt;
54         long                    max_hpages;
55         long                    nr_inodes;
56         long                    min_hpages;
57         enum hugetlbfs_size_type max_val_type;
58         enum hugetlbfs_size_type min_val_type;
59         kuid_t                  uid;
60         kgid_t                  gid;
61         umode_t                 mode;
62 };
63
64 int sysctl_hugetlb_shm_group;
65
66 enum hugetlb_param {
67         Opt_gid,
68         Opt_min_size,
69         Opt_mode,
70         Opt_nr_inodes,
71         Opt_pagesize,
72         Opt_size,
73         Opt_uid,
74 };
75
76 static const struct fs_parameter_spec hugetlb_param_specs[] = {
77         fsparam_u32   ("gid",           Opt_gid),
78         fsparam_string("min_size",      Opt_min_size),
79         fsparam_u32   ("mode",          Opt_mode),
80         fsparam_string("nr_inodes",     Opt_nr_inodes),
81         fsparam_string("pagesize",      Opt_pagesize),
82         fsparam_string("size",          Opt_size),
83         fsparam_u32   ("uid",           Opt_uid),
84         {}
85 };
86
87 static const struct fs_parameter_description hugetlb_fs_parameters = {
88         .name           = "hugetlbfs",
89         .specs          = hugetlb_param_specs,
90 };
91
92 #ifdef CONFIG_NUMA
93 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
94                                         struct inode *inode, pgoff_t index)
95 {
96         vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
97                                                         index);
98 }
99
100 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
101 {
102         mpol_cond_put(vma->vm_policy);
103 }
104 #else
105 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
106                                         struct inode *inode, pgoff_t index)
107 {
108 }
109
110 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
111 {
112 }
113 #endif
114
115 static void huge_pagevec_release(struct pagevec *pvec)
116 {
117         int i;
118
119         for (i = 0; i < pagevec_count(pvec); ++i)
120                 put_page(pvec->pages[i]);
121
122         pagevec_reinit(pvec);
123 }
124
125 /*
126  * Mask used when checking the page offset value passed in via system
127  * calls.  This value will be converted to a loff_t which is signed.
128  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
129  * value.  The extra bit (- 1 in the shift value) is to take the sign
130  * bit into account.
131  */
132 #define PGOFF_LOFFT_MAX \
133         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
134
135 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
136 {
137         struct inode *inode = file_inode(file);
138         loff_t len, vma_len;
139         int ret;
140         struct hstate *h = hstate_file(file);
141
142         /*
143          * vma address alignment (but not the pgoff alignment) has
144          * already been checked by prepare_hugepage_range.  If you add
145          * any error returns here, do so after setting VM_HUGETLB, so
146          * is_vm_hugetlb_page tests below unmap_region go the right
147          * way when do_mmap_pgoff unwinds (may be important on powerpc
148          * and ia64).
149          */
150         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
151         vma->vm_ops = &hugetlb_vm_ops;
152
153         /*
154          * page based offset in vm_pgoff could be sufficiently large to
155          * overflow a loff_t when converted to byte offset.  This can
156          * only happen on architectures where sizeof(loff_t) ==
157          * sizeof(unsigned long).  So, only check in those instances.
158          */
159         if (sizeof(unsigned long) == sizeof(loff_t)) {
160                 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
161                         return -EINVAL;
162         }
163
164         /* must be huge page aligned */
165         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
166                 return -EINVAL;
167
168         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
169         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
170         /* check for overflow */
171         if (len < vma_len)
172                 return -EINVAL;
173
174         inode_lock(inode);
175         file_accessed(file);
176
177         ret = -ENOMEM;
178         if (hugetlb_reserve_pages(inode,
179                                 vma->vm_pgoff >> huge_page_order(h),
180                                 len >> huge_page_shift(h), vma,
181                                 vma->vm_flags))
182                 goto out;
183
184         ret = 0;
185         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
186                 i_size_write(inode, len);
187 out:
188         inode_unlock(inode);
189
190         return ret;
191 }
192
193 /*
194  * Called under down_write(mmap_sem).
195  */
196
197 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
198 static unsigned long
199 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
200                 unsigned long len, unsigned long pgoff, unsigned long flags)
201 {
202         struct mm_struct *mm = current->mm;
203         struct vm_area_struct *vma;
204         struct hstate *h = hstate_file(file);
205         struct vm_unmapped_area_info info;
206
207         if (len & ~huge_page_mask(h))
208                 return -EINVAL;
209         if (len > TASK_SIZE)
210                 return -ENOMEM;
211
212         if (flags & MAP_FIXED) {
213                 if (prepare_hugepage_range(file, addr, len))
214                         return -EINVAL;
215                 return addr;
216         }
217
218         if (addr) {
219                 addr = ALIGN(addr, huge_page_size(h));
220                 vma = find_vma(mm, addr);
221                 if (TASK_SIZE - len >= addr &&
222                     (!vma || addr + len <= vm_start_gap(vma)))
223                         return addr;
224         }
225
226         info.flags = 0;
227         info.length = len;
228         info.low_limit = TASK_UNMAPPED_BASE;
229         info.high_limit = TASK_SIZE;
230         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
231         info.align_offset = 0;
232         return vm_unmapped_area(&info);
233 }
234 #endif
235
236 static size_t
237 hugetlbfs_read_actor(struct page *page, unsigned long offset,
238                         struct iov_iter *to, unsigned long size)
239 {
240         size_t copied = 0;
241         int i, chunksize;
242
243         /* Find which 4k chunk and offset with in that chunk */
244         i = offset >> PAGE_SHIFT;
245         offset = offset & ~PAGE_MASK;
246
247         while (size) {
248                 size_t n;
249                 chunksize = PAGE_SIZE;
250                 if (offset)
251                         chunksize -= offset;
252                 if (chunksize > size)
253                         chunksize = size;
254                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
255                 copied += n;
256                 if (n != chunksize)
257                         return copied;
258                 offset = 0;
259                 size -= chunksize;
260                 i++;
261         }
262         return copied;
263 }
264
265 /*
266  * Support for read() - Find the page attached to f_mapping and copy out the
267  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
268  * since it has PAGE_SIZE assumptions.
269  */
270 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
271 {
272         struct file *file = iocb->ki_filp;
273         struct hstate *h = hstate_file(file);
274         struct address_space *mapping = file->f_mapping;
275         struct inode *inode = mapping->host;
276         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
277         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
278         unsigned long end_index;
279         loff_t isize;
280         ssize_t retval = 0;
281
282         while (iov_iter_count(to)) {
283                 struct page *page;
284                 size_t nr, copied;
285
286                 /* nr is the maximum number of bytes to copy from this page */
287                 nr = huge_page_size(h);
288                 isize = i_size_read(inode);
289                 if (!isize)
290                         break;
291                 end_index = (isize - 1) >> huge_page_shift(h);
292                 if (index > end_index)
293                         break;
294                 if (index == end_index) {
295                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
296                         if (nr <= offset)
297                                 break;
298                 }
299                 nr = nr - offset;
300
301                 /* Find the page */
302                 page = find_lock_page(mapping, index);
303                 if (unlikely(page == NULL)) {
304                         /*
305                          * We have a HOLE, zero out the user-buffer for the
306                          * length of the hole or request.
307                          */
308                         copied = iov_iter_zero(nr, to);
309                 } else {
310                         unlock_page(page);
311
312                         /*
313                          * We have the page, copy it to user space buffer.
314                          */
315                         copied = hugetlbfs_read_actor(page, offset, to, nr);
316                         put_page(page);
317                 }
318                 offset += copied;
319                 retval += copied;
320                 if (copied != nr && iov_iter_count(to)) {
321                         if (!retval)
322                                 retval = -EFAULT;
323                         break;
324                 }
325                 index += offset >> huge_page_shift(h);
326                 offset &= ~huge_page_mask(h);
327         }
328         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
329         return retval;
330 }
331
332 static int hugetlbfs_write_begin(struct file *file,
333                         struct address_space *mapping,
334                         loff_t pos, unsigned len, unsigned flags,
335                         struct page **pagep, void **fsdata)
336 {
337         return -EINVAL;
338 }
339
340 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
341                         loff_t pos, unsigned len, unsigned copied,
342                         struct page *page, void *fsdata)
343 {
344         BUG();
345         return -EINVAL;
346 }
347
348 static void remove_huge_page(struct page *page)
349 {
350         ClearPageDirty(page);
351         ClearPageUptodate(page);
352         delete_from_page_cache(page);
353 }
354
355 static void
356 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end)
357 {
358         struct vm_area_struct *vma;
359
360         /*
361          * end == 0 indicates that the entire range after
362          * start should be unmapped.
363          */
364         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
365                 unsigned long v_offset;
366                 unsigned long v_end;
367
368                 /*
369                  * Can the expression below overflow on 32-bit arches?
370                  * No, because the interval tree returns us only those vmas
371                  * which overlap the truncated area starting at pgoff,
372                  * and no vma on a 32-bit arch can span beyond the 4GB.
373                  */
374                 if (vma->vm_pgoff < start)
375                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
376                 else
377                         v_offset = 0;
378
379                 if (!end)
380                         v_end = vma->vm_end;
381                 else {
382                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
383                                                         + vma->vm_start;
384                         if (v_end > vma->vm_end)
385                                 v_end = vma->vm_end;
386                 }
387
388                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
389                                                                         NULL);
390         }
391 }
392
393 /*
394  * remove_inode_hugepages handles two distinct cases: truncation and hole
395  * punch.  There are subtle differences in operation for each case.
396  *
397  * truncation is indicated by end of range being LLONG_MAX
398  *      In this case, we first scan the range and release found pages.
399  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
400  *      maps and global counts.  Page faults can not race with truncation
401  *      in this routine.  hugetlb_no_page() prevents page faults in the
402  *      truncated range.  It checks i_size before allocation, and again after
403  *      with the page table lock for the page held.  The same lock must be
404  *      acquired to unmap a page.
405  * hole punch is indicated if end is not LLONG_MAX
406  *      In the hole punch case we scan the range and release found pages.
407  *      Only when releasing a page is the associated region/reserv map
408  *      deleted.  The region/reserv map for ranges without associated
409  *      pages are not modified.  Page faults can race with hole punch.
410  *      This is indicated if we find a mapped page.
411  * Note: If the passed end of range value is beyond the end of file, but
412  * not LLONG_MAX this routine still performs a hole punch operation.
413  */
414 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
415                                    loff_t lend)
416 {
417         struct hstate *h = hstate_inode(inode);
418         struct address_space *mapping = &inode->i_data;
419         const pgoff_t start = lstart >> huge_page_shift(h);
420         const pgoff_t end = lend >> huge_page_shift(h);
421         struct vm_area_struct pseudo_vma;
422         struct pagevec pvec;
423         pgoff_t next, index;
424         int i, freed = 0;
425         bool truncate_op = (lend == LLONG_MAX);
426
427         vma_init(&pseudo_vma, current->mm);
428         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
429         pagevec_init(&pvec);
430         next = start;
431         while (next < end) {
432                 /*
433                  * When no more pages are found, we are done.
434                  */
435                 if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
436                         break;
437
438                 for (i = 0; i < pagevec_count(&pvec); ++i) {
439                         struct page *page = pvec.pages[i];
440                         u32 hash;
441
442                         index = page->index;
443                         hash = hugetlb_fault_mutex_hash(h, current->mm,
444                                                         &pseudo_vma,
445                                                         mapping, index, 0);
446                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
447
448                         /*
449                          * If page is mapped, it was faulted in after being
450                          * unmapped in caller.  Unmap (again) now after taking
451                          * the fault mutex.  The mutex will prevent faults
452                          * until we finish removing the page.
453                          *
454                          * This race can only happen in the hole punch case.
455                          * Getting here in a truncate operation is a bug.
456                          */
457                         if (unlikely(page_mapped(page))) {
458                                 BUG_ON(truncate_op);
459
460                                 i_mmap_lock_write(mapping);
461                                 hugetlb_vmdelete_list(&mapping->i_mmap,
462                                         index * pages_per_huge_page(h),
463                                         (index + 1) * pages_per_huge_page(h));
464                                 i_mmap_unlock_write(mapping);
465                         }
466
467                         lock_page(page);
468                         /*
469                          * We must free the huge page and remove from page
470                          * cache (remove_huge_page) BEFORE removing the
471                          * region/reserve map (hugetlb_unreserve_pages).  In
472                          * rare out of memory conditions, removal of the
473                          * region/reserve map could fail. Correspondingly,
474                          * the subpool and global reserve usage count can need
475                          * to be adjusted.
476                          */
477                         VM_BUG_ON(PagePrivate(page));
478                         remove_huge_page(page);
479                         freed++;
480                         if (!truncate_op) {
481                                 if (unlikely(hugetlb_unreserve_pages(inode,
482                                                         index, index + 1, 1)))
483                                         hugetlb_fix_reserve_counts(inode);
484                         }
485
486                         unlock_page(page);
487                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
488                 }
489                 huge_pagevec_release(&pvec);
490                 cond_resched();
491         }
492
493         if (truncate_op)
494                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
495 }
496
497 static void hugetlbfs_evict_inode(struct inode *inode)
498 {
499         struct resv_map *resv_map;
500
501         remove_inode_hugepages(inode, 0, LLONG_MAX);
502         resv_map = (struct resv_map *)inode->i_mapping->private_data;
503         /* root inode doesn't have the resv_map, so we should check it */
504         if (resv_map)
505                 resv_map_release(&resv_map->refs);
506         clear_inode(inode);
507 }
508
509 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
510 {
511         pgoff_t pgoff;
512         struct address_space *mapping = inode->i_mapping;
513         struct hstate *h = hstate_inode(inode);
514
515         BUG_ON(offset & ~huge_page_mask(h));
516         pgoff = offset >> PAGE_SHIFT;
517
518         i_size_write(inode, offset);
519         i_mmap_lock_write(mapping);
520         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
521                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
522         i_mmap_unlock_write(mapping);
523         remove_inode_hugepages(inode, offset, LLONG_MAX);
524         return 0;
525 }
526
527 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
528 {
529         struct hstate *h = hstate_inode(inode);
530         loff_t hpage_size = huge_page_size(h);
531         loff_t hole_start, hole_end;
532
533         /*
534          * For hole punch round up the beginning offset of the hole and
535          * round down the end.
536          */
537         hole_start = round_up(offset, hpage_size);
538         hole_end = round_down(offset + len, hpage_size);
539
540         if (hole_end > hole_start) {
541                 struct address_space *mapping = inode->i_mapping;
542                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
543
544                 inode_lock(inode);
545
546                 /* protected by i_mutex */
547                 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
548                         inode_unlock(inode);
549                         return -EPERM;
550                 }
551
552                 i_mmap_lock_write(mapping);
553                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
554                         hugetlb_vmdelete_list(&mapping->i_mmap,
555                                                 hole_start >> PAGE_SHIFT,
556                                                 hole_end  >> PAGE_SHIFT);
557                 i_mmap_unlock_write(mapping);
558                 remove_inode_hugepages(inode, hole_start, hole_end);
559                 inode_unlock(inode);
560         }
561
562         return 0;
563 }
564
565 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
566                                 loff_t len)
567 {
568         struct inode *inode = file_inode(file);
569         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
570         struct address_space *mapping = inode->i_mapping;
571         struct hstate *h = hstate_inode(inode);
572         struct vm_area_struct pseudo_vma;
573         struct mm_struct *mm = current->mm;
574         loff_t hpage_size = huge_page_size(h);
575         unsigned long hpage_shift = huge_page_shift(h);
576         pgoff_t start, index, end;
577         int error;
578         u32 hash;
579
580         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
581                 return -EOPNOTSUPP;
582
583         if (mode & FALLOC_FL_PUNCH_HOLE)
584                 return hugetlbfs_punch_hole(inode, offset, len);
585
586         /*
587          * Default preallocate case.
588          * For this range, start is rounded down and end is rounded up
589          * as well as being converted to page offsets.
590          */
591         start = offset >> hpage_shift;
592         end = (offset + len + hpage_size - 1) >> hpage_shift;
593
594         inode_lock(inode);
595
596         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
597         error = inode_newsize_ok(inode, offset + len);
598         if (error)
599                 goto out;
600
601         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
602                 error = -EPERM;
603                 goto out;
604         }
605
606         /*
607          * Initialize a pseudo vma as this is required by the huge page
608          * allocation routines.  If NUMA is configured, use page index
609          * as input to create an allocation policy.
610          */
611         vma_init(&pseudo_vma, mm);
612         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
613         pseudo_vma.vm_file = file;
614
615         for (index = start; index < end; index++) {
616                 /*
617                  * This is supposed to be the vaddr where the page is being
618                  * faulted in, but we have no vaddr here.
619                  */
620                 struct page *page;
621                 unsigned long addr;
622                 int avoid_reserve = 0;
623
624                 cond_resched();
625
626                 /*
627                  * fallocate(2) manpage permits EINTR; we may have been
628                  * interrupted because we are using up too much memory.
629                  */
630                 if (signal_pending(current)) {
631                         error = -EINTR;
632                         break;
633                 }
634
635                 /* Set numa allocation policy based on index */
636                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
637
638                 /* addr is the offset within the file (zero based) */
639                 addr = index * hpage_size;
640
641                 /* mutex taken here, fault path and hole punch */
642                 hash = hugetlb_fault_mutex_hash(h, mm, &pseudo_vma, mapping,
643                                                 index, addr);
644                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
645
646                 /* See if already present in mapping to avoid alloc/free */
647                 page = find_get_page(mapping, index);
648                 if (page) {
649                         put_page(page);
650                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
651                         hugetlb_drop_vma_policy(&pseudo_vma);
652                         continue;
653                 }
654
655                 /* Allocate page and add to page cache */
656                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
657                 hugetlb_drop_vma_policy(&pseudo_vma);
658                 if (IS_ERR(page)) {
659                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
660                         error = PTR_ERR(page);
661                         goto out;
662                 }
663                 clear_huge_page(page, addr, pages_per_huge_page(h));
664                 __SetPageUptodate(page);
665                 error = huge_add_to_page_cache(page, mapping, index);
666                 if (unlikely(error)) {
667                         put_page(page);
668                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
669                         goto out;
670                 }
671
672                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
673
674                 /*
675                  * unlock_page because locked by add_to_page_cache()
676                  * page_put due to reference from alloc_huge_page()
677                  */
678                 unlock_page(page);
679                 put_page(page);
680         }
681
682         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
683                 i_size_write(inode, offset + len);
684         inode->i_ctime = current_time(inode);
685 out:
686         inode_unlock(inode);
687         return error;
688 }
689
690 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
691 {
692         struct inode *inode = d_inode(dentry);
693         struct hstate *h = hstate_inode(inode);
694         int error;
695         unsigned int ia_valid = attr->ia_valid;
696         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
697
698         BUG_ON(!inode);
699
700         error = setattr_prepare(dentry, attr);
701         if (error)
702                 return error;
703
704         if (ia_valid & ATTR_SIZE) {
705                 loff_t oldsize = inode->i_size;
706                 loff_t newsize = attr->ia_size;
707
708                 if (newsize & ~huge_page_mask(h))
709                         return -EINVAL;
710                 /* protected by i_mutex */
711                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
712                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
713                         return -EPERM;
714                 error = hugetlb_vmtruncate(inode, newsize);
715                 if (error)
716                         return error;
717         }
718
719         setattr_copy(inode, attr);
720         mark_inode_dirty(inode);
721         return 0;
722 }
723
724 static struct inode *hugetlbfs_get_root(struct super_block *sb,
725                                         struct hugetlbfs_fs_context *ctx)
726 {
727         struct inode *inode;
728
729         inode = new_inode(sb);
730         if (inode) {
731                 inode->i_ino = get_next_ino();
732                 inode->i_mode = S_IFDIR | ctx->mode;
733                 inode->i_uid = ctx->uid;
734                 inode->i_gid = ctx->gid;
735                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
736                 inode->i_op = &hugetlbfs_dir_inode_operations;
737                 inode->i_fop = &simple_dir_operations;
738                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
739                 inc_nlink(inode);
740                 lockdep_annotate_inode_mutex_key(inode);
741         }
742         return inode;
743 }
744
745 /*
746  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
747  * be taken from reclaim -- unlike regular filesystems. This needs an
748  * annotation because huge_pmd_share() does an allocation under hugetlb's
749  * i_mmap_rwsem.
750  */
751 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
752
753 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
754                                         struct inode *dir,
755                                         umode_t mode, dev_t dev)
756 {
757         struct inode *inode;
758         struct resv_map *resv_map = NULL;
759
760         /*
761          * Reserve maps are only needed for inodes that can have associated
762          * page allocations.
763          */
764         if (S_ISREG(mode) || S_ISLNK(mode)) {
765                 resv_map = resv_map_alloc();
766                 if (!resv_map)
767                         return NULL;
768         }
769
770         inode = new_inode(sb);
771         if (inode) {
772                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
773
774                 inode->i_ino = get_next_ino();
775                 inode_init_owner(inode, dir, mode);
776                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
777                                 &hugetlbfs_i_mmap_rwsem_key);
778                 inode->i_mapping->a_ops = &hugetlbfs_aops;
779                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
780                 inode->i_mapping->private_data = resv_map;
781                 info->seals = F_SEAL_SEAL;
782                 switch (mode & S_IFMT) {
783                 default:
784                         init_special_inode(inode, mode, dev);
785                         break;
786                 case S_IFREG:
787                         inode->i_op = &hugetlbfs_inode_operations;
788                         inode->i_fop = &hugetlbfs_file_operations;
789                         break;
790                 case S_IFDIR:
791                         inode->i_op = &hugetlbfs_dir_inode_operations;
792                         inode->i_fop = &simple_dir_operations;
793
794                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
795                         inc_nlink(inode);
796                         break;
797                 case S_IFLNK:
798                         inode->i_op = &page_symlink_inode_operations;
799                         inode_nohighmem(inode);
800                         break;
801                 }
802                 lockdep_annotate_inode_mutex_key(inode);
803         } else {
804                 if (resv_map)
805                         kref_put(&resv_map->refs, resv_map_release);
806         }
807
808         return inode;
809 }
810
811 /*
812  * File creation. Allocate an inode, and we're done..
813  */
814 static int hugetlbfs_mknod(struct inode *dir,
815                         struct dentry *dentry, umode_t mode, dev_t dev)
816 {
817         struct inode *inode;
818         int error = -ENOSPC;
819
820         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
821         if (inode) {
822                 dir->i_ctime = dir->i_mtime = current_time(dir);
823                 d_instantiate(dentry, inode);
824                 dget(dentry);   /* Extra count - pin the dentry in core */
825                 error = 0;
826         }
827         return error;
828 }
829
830 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
831 {
832         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
833         if (!retval)
834                 inc_nlink(dir);
835         return retval;
836 }
837
838 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
839 {
840         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
841 }
842
843 static int hugetlbfs_symlink(struct inode *dir,
844                         struct dentry *dentry, const char *symname)
845 {
846         struct inode *inode;
847         int error = -ENOSPC;
848
849         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
850         if (inode) {
851                 int l = strlen(symname)+1;
852                 error = page_symlink(inode, symname, l);
853                 if (!error) {
854                         d_instantiate(dentry, inode);
855                         dget(dentry);
856                 } else
857                         iput(inode);
858         }
859         dir->i_ctime = dir->i_mtime = current_time(dir);
860
861         return error;
862 }
863
864 /*
865  * mark the head page dirty
866  */
867 static int hugetlbfs_set_page_dirty(struct page *page)
868 {
869         struct page *head = compound_head(page);
870
871         SetPageDirty(head);
872         return 0;
873 }
874
875 static int hugetlbfs_migrate_page(struct address_space *mapping,
876                                 struct page *newpage, struct page *page,
877                                 enum migrate_mode mode)
878 {
879         int rc;
880
881         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
882         if (rc != MIGRATEPAGE_SUCCESS)
883                 return rc;
884
885         /*
886          * page_private is subpool pointer in hugetlb pages.  Transfer to
887          * new page.  PagePrivate is not associated with page_private for
888          * hugetlb pages and can not be set here as only page_huge_active
889          * pages can be migrated.
890          */
891         if (page_private(page)) {
892                 set_page_private(newpage, page_private(page));
893                 set_page_private(page, 0);
894         }
895
896         if (mode != MIGRATE_SYNC_NO_COPY)
897                 migrate_page_copy(newpage, page);
898         else
899                 migrate_page_states(newpage, page);
900
901         return MIGRATEPAGE_SUCCESS;
902 }
903
904 static int hugetlbfs_error_remove_page(struct address_space *mapping,
905                                 struct page *page)
906 {
907         struct inode *inode = mapping->host;
908         pgoff_t index = page->index;
909
910         remove_huge_page(page);
911         if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
912                 hugetlb_fix_reserve_counts(inode);
913
914         return 0;
915 }
916
917 /*
918  * Display the mount options in /proc/mounts.
919  */
920 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
921 {
922         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
923         struct hugepage_subpool *spool = sbinfo->spool;
924         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
925         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
926         char mod;
927
928         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
929                 seq_printf(m, ",uid=%u",
930                            from_kuid_munged(&init_user_ns, sbinfo->uid));
931         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
932                 seq_printf(m, ",gid=%u",
933                            from_kgid_munged(&init_user_ns, sbinfo->gid));
934         if (sbinfo->mode != 0755)
935                 seq_printf(m, ",mode=%o", sbinfo->mode);
936         if (sbinfo->max_inodes != -1)
937                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
938
939         hpage_size /= 1024;
940         mod = 'K';
941         if (hpage_size >= 1024) {
942                 hpage_size /= 1024;
943                 mod = 'M';
944         }
945         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
946         if (spool) {
947                 if (spool->max_hpages != -1)
948                         seq_printf(m, ",size=%llu",
949                                    (unsigned long long)spool->max_hpages << hpage_shift);
950                 if (spool->min_hpages != -1)
951                         seq_printf(m, ",min_size=%llu",
952                                    (unsigned long long)spool->min_hpages << hpage_shift);
953         }
954         return 0;
955 }
956
957 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
958 {
959         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
960         struct hstate *h = hstate_inode(d_inode(dentry));
961
962         buf->f_type = HUGETLBFS_MAGIC;
963         buf->f_bsize = huge_page_size(h);
964         if (sbinfo) {
965                 spin_lock(&sbinfo->stat_lock);
966                 /* If no limits set, just report 0 for max/free/used
967                  * blocks, like simple_statfs() */
968                 if (sbinfo->spool) {
969                         long free_pages;
970
971                         spin_lock(&sbinfo->spool->lock);
972                         buf->f_blocks = sbinfo->spool->max_hpages;
973                         free_pages = sbinfo->spool->max_hpages
974                                 - sbinfo->spool->used_hpages;
975                         buf->f_bavail = buf->f_bfree = free_pages;
976                         spin_unlock(&sbinfo->spool->lock);
977                         buf->f_files = sbinfo->max_inodes;
978                         buf->f_ffree = sbinfo->free_inodes;
979                 }
980                 spin_unlock(&sbinfo->stat_lock);
981         }
982         buf->f_namelen = NAME_MAX;
983         return 0;
984 }
985
986 static void hugetlbfs_put_super(struct super_block *sb)
987 {
988         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
989
990         if (sbi) {
991                 sb->s_fs_info = NULL;
992
993                 if (sbi->spool)
994                         hugepage_put_subpool(sbi->spool);
995
996                 kfree(sbi);
997         }
998 }
999
1000 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1001 {
1002         if (sbinfo->free_inodes >= 0) {
1003                 spin_lock(&sbinfo->stat_lock);
1004                 if (unlikely(!sbinfo->free_inodes)) {
1005                         spin_unlock(&sbinfo->stat_lock);
1006                         return 0;
1007                 }
1008                 sbinfo->free_inodes--;
1009                 spin_unlock(&sbinfo->stat_lock);
1010         }
1011
1012         return 1;
1013 }
1014
1015 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1016 {
1017         if (sbinfo->free_inodes >= 0) {
1018                 spin_lock(&sbinfo->stat_lock);
1019                 sbinfo->free_inodes++;
1020                 spin_unlock(&sbinfo->stat_lock);
1021         }
1022 }
1023
1024
1025 static struct kmem_cache *hugetlbfs_inode_cachep;
1026
1027 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1028 {
1029         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1030         struct hugetlbfs_inode_info *p;
1031
1032         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1033                 return NULL;
1034         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
1035         if (unlikely(!p)) {
1036                 hugetlbfs_inc_free_inodes(sbinfo);
1037                 return NULL;
1038         }
1039
1040         /*
1041          * Any time after allocation, hugetlbfs_destroy_inode can be called
1042          * for the inode.  mpol_free_shared_policy is unconditionally called
1043          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
1044          * in case of a quick call to destroy.
1045          *
1046          * Note that the policy is initialized even if we are creating a
1047          * private inode.  This simplifies hugetlbfs_destroy_inode.
1048          */
1049         mpol_shared_policy_init(&p->policy, NULL);
1050
1051         return &p->vfs_inode;
1052 }
1053
1054 static void hugetlbfs_free_inode(struct inode *inode)
1055 {
1056         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1057 }
1058
1059 static void hugetlbfs_destroy_inode(struct inode *inode)
1060 {
1061         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1062         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1063 }
1064
1065 static const struct address_space_operations hugetlbfs_aops = {
1066         .write_begin    = hugetlbfs_write_begin,
1067         .write_end      = hugetlbfs_write_end,
1068         .set_page_dirty = hugetlbfs_set_page_dirty,
1069         .migratepage    = hugetlbfs_migrate_page,
1070         .error_remove_page      = hugetlbfs_error_remove_page,
1071 };
1072
1073
1074 static void init_once(void *foo)
1075 {
1076         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1077
1078         inode_init_once(&ei->vfs_inode);
1079 }
1080
1081 const struct file_operations hugetlbfs_file_operations = {
1082         .read_iter              = hugetlbfs_read_iter,
1083         .mmap                   = hugetlbfs_file_mmap,
1084         .fsync                  = noop_fsync,
1085         .get_unmapped_area      = hugetlb_get_unmapped_area,
1086         .llseek                 = default_llseek,
1087         .fallocate              = hugetlbfs_fallocate,
1088 };
1089
1090 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1091         .create         = hugetlbfs_create,
1092         .lookup         = simple_lookup,
1093         .link           = simple_link,
1094         .unlink         = simple_unlink,
1095         .symlink        = hugetlbfs_symlink,
1096         .mkdir          = hugetlbfs_mkdir,
1097         .rmdir          = simple_rmdir,
1098         .mknod          = hugetlbfs_mknod,
1099         .rename         = simple_rename,
1100         .setattr        = hugetlbfs_setattr,
1101 };
1102
1103 static const struct inode_operations hugetlbfs_inode_operations = {
1104         .setattr        = hugetlbfs_setattr,
1105 };
1106
1107 static const struct super_operations hugetlbfs_ops = {
1108         .alloc_inode    = hugetlbfs_alloc_inode,
1109         .free_inode     = hugetlbfs_free_inode,
1110         .destroy_inode  = hugetlbfs_destroy_inode,
1111         .evict_inode    = hugetlbfs_evict_inode,
1112         .statfs         = hugetlbfs_statfs,
1113         .put_super      = hugetlbfs_put_super,
1114         .show_options   = hugetlbfs_show_options,
1115 };
1116
1117 /*
1118  * Convert size option passed from command line to number of huge pages
1119  * in the pool specified by hstate.  Size option could be in bytes
1120  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1121  */
1122 static long
1123 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1124                          enum hugetlbfs_size_type val_type)
1125 {
1126         if (val_type == NO_SIZE)
1127                 return -1;
1128
1129         if (val_type == SIZE_PERCENT) {
1130                 size_opt <<= huge_page_shift(h);
1131                 size_opt *= h->max_huge_pages;
1132                 do_div(size_opt, 100);
1133         }
1134
1135         size_opt >>= huge_page_shift(h);
1136         return size_opt;
1137 }
1138
1139 /*
1140  * Parse one mount parameter.
1141  */
1142 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1143 {
1144         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1145         struct fs_parse_result result;
1146         char *rest;
1147         unsigned long ps;
1148         int opt;
1149
1150         opt = fs_parse(fc, &hugetlb_fs_parameters, param, &result);
1151         if (opt < 0)
1152                 return opt;
1153
1154         switch (opt) {
1155         case Opt_uid:
1156                 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1157                 if (!uid_valid(ctx->uid))
1158                         goto bad_val;
1159                 return 0;
1160
1161         case Opt_gid:
1162                 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1163                 if (!gid_valid(ctx->gid))
1164                         goto bad_val;
1165                 return 0;
1166
1167         case Opt_mode:
1168                 ctx->mode = result.uint_32 & 01777U;
1169                 return 0;
1170
1171         case Opt_size:
1172                 /* memparse() will accept a K/M/G without a digit */
1173                 if (!isdigit(param->string[0]))
1174                         goto bad_val;
1175                 ctx->max_size_opt = memparse(param->string, &rest);
1176                 ctx->max_val_type = SIZE_STD;
1177                 if (*rest == '%')
1178                         ctx->max_val_type = SIZE_PERCENT;
1179                 return 0;
1180
1181         case Opt_nr_inodes:
1182                 /* memparse() will accept a K/M/G without a digit */
1183                 if (!isdigit(param->string[0]))
1184                         goto bad_val;
1185                 ctx->nr_inodes = memparse(param->string, &rest);
1186                 return 0;
1187
1188         case Opt_pagesize:
1189                 ps = memparse(param->string, &rest);
1190                 ctx->hstate = size_to_hstate(ps);
1191                 if (!ctx->hstate) {
1192                         pr_err("Unsupported page size %lu MB\n", ps >> 20);
1193                         return -EINVAL;
1194                 }
1195                 return 0;
1196
1197         case Opt_min_size:
1198                 /* memparse() will accept a K/M/G without a digit */
1199                 if (!isdigit(param->string[0]))
1200                         goto bad_val;
1201                 ctx->min_size_opt = memparse(param->string, &rest);
1202                 ctx->min_val_type = SIZE_STD;
1203                 if (*rest == '%')
1204                         ctx->min_val_type = SIZE_PERCENT;
1205                 return 0;
1206
1207         default:
1208                 return -EINVAL;
1209         }
1210
1211 bad_val:
1212         return invalf(fc, "hugetlbfs: Bad value '%s' for mount option '%s'\n",
1213                       param->string, param->key);
1214 }
1215
1216 /*
1217  * Validate the parsed options.
1218  */
1219 static int hugetlbfs_validate(struct fs_context *fc)
1220 {
1221         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1222
1223         /*
1224          * Use huge page pool size (in hstate) to convert the size
1225          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1226          */
1227         ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1228                                                    ctx->max_size_opt,
1229                                                    ctx->max_val_type);
1230         ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1231                                                    ctx->min_size_opt,
1232                                                    ctx->min_val_type);
1233
1234         /*
1235          * If max_size was specified, then min_size must be smaller
1236          */
1237         if (ctx->max_val_type > NO_SIZE &&
1238             ctx->min_hpages > ctx->max_hpages) {
1239                 pr_err("Minimum size can not be greater than maximum size\n");
1240                 return -EINVAL;
1241         }
1242
1243         return 0;
1244 }
1245
1246 static int
1247 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1248 {
1249         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1250         struct hugetlbfs_sb_info *sbinfo;
1251
1252         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1253         if (!sbinfo)
1254                 return -ENOMEM;
1255         sb->s_fs_info = sbinfo;
1256         spin_lock_init(&sbinfo->stat_lock);
1257         sbinfo->hstate          = ctx->hstate;
1258         sbinfo->max_inodes      = ctx->nr_inodes;
1259         sbinfo->free_inodes     = ctx->nr_inodes;
1260         sbinfo->spool           = NULL;
1261         sbinfo->uid             = ctx->uid;
1262         sbinfo->gid             = ctx->gid;
1263         sbinfo->mode            = ctx->mode;
1264
1265         /*
1266          * Allocate and initialize subpool if maximum or minimum size is
1267          * specified.  Any needed reservations (for minimim size) are taken
1268          * taken when the subpool is created.
1269          */
1270         if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1271                 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1272                                                      ctx->max_hpages,
1273                                                      ctx->min_hpages);
1274                 if (!sbinfo->spool)
1275                         goto out_free;
1276         }
1277         sb->s_maxbytes = MAX_LFS_FILESIZE;
1278         sb->s_blocksize = huge_page_size(ctx->hstate);
1279         sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1280         sb->s_magic = HUGETLBFS_MAGIC;
1281         sb->s_op = &hugetlbfs_ops;
1282         sb->s_time_gran = 1;
1283         sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1284         if (!sb->s_root)
1285                 goto out_free;
1286         return 0;
1287 out_free:
1288         kfree(sbinfo->spool);
1289         kfree(sbinfo);
1290         return -ENOMEM;
1291 }
1292
1293 static int hugetlbfs_get_tree(struct fs_context *fc)
1294 {
1295         int err = hugetlbfs_validate(fc);
1296         if (err)
1297                 return err;
1298         return vfs_get_super(fc, vfs_get_independent_super, hugetlbfs_fill_super);
1299 }
1300
1301 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1302 {
1303         kfree(fc->fs_private);
1304 }
1305
1306 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1307         .free           = hugetlbfs_fs_context_free,
1308         .parse_param    = hugetlbfs_parse_param,
1309         .get_tree       = hugetlbfs_get_tree,
1310 };
1311
1312 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1313 {
1314         struct hugetlbfs_fs_context *ctx;
1315
1316         ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1317         if (!ctx)
1318                 return -ENOMEM;
1319
1320         ctx->max_hpages = -1; /* No limit on size by default */
1321         ctx->nr_inodes  = -1; /* No limit on number of inodes by default */
1322         ctx->uid        = current_fsuid();
1323         ctx->gid        = current_fsgid();
1324         ctx->mode       = 0755;
1325         ctx->hstate     = &default_hstate;
1326         ctx->min_hpages = -1; /* No default minimum size */
1327         ctx->max_val_type = NO_SIZE;
1328         ctx->min_val_type = NO_SIZE;
1329         fc->fs_private = ctx;
1330         fc->ops = &hugetlbfs_fs_context_ops;
1331         return 0;
1332 }
1333
1334 static struct file_system_type hugetlbfs_fs_type = {
1335         .name                   = "hugetlbfs",
1336         .init_fs_context        = hugetlbfs_init_fs_context,
1337         .parameters             = &hugetlb_fs_parameters,
1338         .kill_sb                = kill_litter_super,
1339 };
1340
1341 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1342
1343 static int can_do_hugetlb_shm(void)
1344 {
1345         kgid_t shm_group;
1346         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1347         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1348 }
1349
1350 static int get_hstate_idx(int page_size_log)
1351 {
1352         struct hstate *h = hstate_sizelog(page_size_log);
1353
1354         if (!h)
1355                 return -1;
1356         return h - hstates;
1357 }
1358
1359 /*
1360  * Note that size should be aligned to proper hugepage size in caller side,
1361  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1362  */
1363 struct file *hugetlb_file_setup(const char *name, size_t size,
1364                                 vm_flags_t acctflag, struct user_struct **user,
1365                                 int creat_flags, int page_size_log)
1366 {
1367         struct inode *inode;
1368         struct vfsmount *mnt;
1369         int hstate_idx;
1370         struct file *file;
1371
1372         hstate_idx = get_hstate_idx(page_size_log);
1373         if (hstate_idx < 0)
1374                 return ERR_PTR(-ENODEV);
1375
1376         *user = NULL;
1377         mnt = hugetlbfs_vfsmount[hstate_idx];
1378         if (!mnt)
1379                 return ERR_PTR(-ENOENT);
1380
1381         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1382                 *user = current_user();
1383                 if (user_shm_lock(size, *user)) {
1384                         task_lock(current);
1385                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1386                                 current->comm, current->pid);
1387                         task_unlock(current);
1388                 } else {
1389                         *user = NULL;
1390                         return ERR_PTR(-EPERM);
1391                 }
1392         }
1393
1394         file = ERR_PTR(-ENOSPC);
1395         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1396         if (!inode)
1397                 goto out;
1398         if (creat_flags == HUGETLB_SHMFS_INODE)
1399                 inode->i_flags |= S_PRIVATE;
1400
1401         inode->i_size = size;
1402         clear_nlink(inode);
1403
1404         if (hugetlb_reserve_pages(inode, 0,
1405                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1406                         acctflag))
1407                 file = ERR_PTR(-ENOMEM);
1408         else
1409                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1410                                         &hugetlbfs_file_operations);
1411         if (!IS_ERR(file))
1412                 return file;
1413
1414         iput(inode);
1415 out:
1416         if (*user) {
1417                 user_shm_unlock(size, *user);
1418                 *user = NULL;
1419         }
1420         return file;
1421 }
1422
1423 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1424 {
1425         struct fs_context *fc;
1426         struct vfsmount *mnt;
1427
1428         fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1429         if (IS_ERR(fc)) {
1430                 mnt = ERR_CAST(fc);
1431         } else {
1432                 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1433                 ctx->hstate = h;
1434                 mnt = fc_mount(fc);
1435                 put_fs_context(fc);
1436         }
1437         if (IS_ERR(mnt))
1438                 pr_err("Cannot mount internal hugetlbfs for page size %uK",
1439                        1U << (h->order + PAGE_SHIFT - 10));
1440         return mnt;
1441 }
1442
1443 static int __init init_hugetlbfs_fs(void)
1444 {
1445         struct vfsmount *mnt;
1446         struct hstate *h;
1447         int error;
1448         int i;
1449
1450         if (!hugepages_supported()) {
1451                 pr_info("disabling because there are no supported hugepage sizes\n");
1452                 return -ENOTSUPP;
1453         }
1454
1455         error = -ENOMEM;
1456         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1457                                         sizeof(struct hugetlbfs_inode_info),
1458                                         0, SLAB_ACCOUNT, init_once);
1459         if (hugetlbfs_inode_cachep == NULL)
1460                 goto out2;
1461
1462         error = register_filesystem(&hugetlbfs_fs_type);
1463         if (error)
1464                 goto out;
1465
1466         i = 0;
1467         for_each_hstate(h) {
1468                 mnt = mount_one_hugetlbfs(h);
1469                 if (IS_ERR(mnt) && i == 0) {
1470                         error = PTR_ERR(mnt);
1471                         goto out;
1472                 }
1473                 hugetlbfs_vfsmount[i] = mnt;
1474                 i++;
1475         }
1476
1477         return 0;
1478
1479  out:
1480         kmem_cache_destroy(hugetlbfs_inode_cachep);
1481  out2:
1482         return error;
1483 }
1484 fs_initcall(init_hugetlbfs_fs)