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Revert "tty: hvc: Fix data abort due to race in hvc_open"
[linux/fpc-iii.git] / fs / hugetlbfs / inode.c
blob991c60c7ffe06efe4e99548440aaa1bea158a476
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_fs_parameters[] = {
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 #ifdef CONFIG_NUMA
88 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
89 struct inode *inode, pgoff_t index)
90 {
91 vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
92 index);
93 }
94
95 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
96 {
97 mpol_cond_put(vma->vm_policy);
98 }
99 #else
100 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
101 struct inode *inode, pgoff_t index)
102 {
103 }
104
105 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
106 {
107 }
108 #endif
109
110 static void huge_pagevec_release(struct pagevec *pvec)
111 {
112 int i;
113
114 for (i = 0; i < pagevec_count(pvec); ++i)
115 put_page(pvec->pages[i]);
116
117 pagevec_reinit(pvec);
118 }
119
120 /*
121 * Mask used when checking the page offset value passed in via system
122 * calls. This value will be converted to a loff_t which is signed.
123 * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
124 * value. The extra bit (- 1 in the shift value) is to take the sign
125 * bit into account.
126 */
127 #define PGOFF_LOFFT_MAX \
128 (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1)))
129
130 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
131 {
132 struct inode *inode = file_inode(file);
133 loff_t len, vma_len;
134 int ret;
135 struct hstate *h = hstate_file(file);
136
137 /*
138 * vma address alignment (but not the pgoff alignment) has
139 * already been checked by prepare_hugepage_range. If you add
140 * any error returns here, do so after setting VM_HUGETLB, so
141 * is_vm_hugetlb_page tests below unmap_region go the right
142 * way when do_mmap_pgoff unwinds (may be important on powerpc
143 * and ia64).
144 */
145 vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
146 vma->vm_ops = &hugetlb_vm_ops;
147
148 /*
149 * page based offset in vm_pgoff could be sufficiently large to
150 * overflow a loff_t when converted to byte offset. This can
151 * only happen on architectures where sizeof(loff_t) ==
152 * sizeof(unsigned long). So, only check in those instances.
153 */
154 if (sizeof(unsigned long) == sizeof(loff_t)) {
155 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
156 return -EINVAL;
157 }
158
159 /* must be huge page aligned */
160 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
161 return -EINVAL;
162
163 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
164 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
165 /* check for overflow */
166 if (len < vma_len)
167 return -EINVAL;
168
169 inode_lock(inode);
170 file_accessed(file);
171
172 ret = -ENOMEM;
173 if (hugetlb_reserve_pages(inode,
174 vma->vm_pgoff >> huge_page_order(h),
175 len >> huge_page_shift(h), vma,
176 vma->vm_flags))
177 goto out;
178
179 ret = 0;
180 if (vma->vm_flags & VM_WRITE && inode->i_size < len)
181 i_size_write(inode, len);
182 out:
183 inode_unlock(inode);
184
185 return ret;
186 }
187
188 /*
189 * Called under down_write(mmap_sem).
190 */
191
192 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
193 static unsigned long
194 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
195 unsigned long len, unsigned long pgoff, unsigned long flags)
196 {
197 struct mm_struct *mm = current->mm;
198 struct vm_area_struct *vma;
199 struct hstate *h = hstate_file(file);
200 struct vm_unmapped_area_info info;
201
202 if (len & ~huge_page_mask(h))
203 return -EINVAL;
204 if (len > TASK_SIZE)
205 return -ENOMEM;
206
207 if (flags & MAP_FIXED) {
208 if (prepare_hugepage_range(file, addr, len))
209 return -EINVAL;
210 return addr;
211 }
212
213 if (addr) {
214 addr = ALIGN(addr, huge_page_size(h));
215 vma = find_vma(mm, addr);
216 if (TASK_SIZE - len >= addr &&
217 (!vma || addr + len <= vm_start_gap(vma)))
218 return addr;
219 }
220
221 info.flags = 0;
222 info.length = len;
223 info.low_limit = TASK_UNMAPPED_BASE;
224 info.high_limit = TASK_SIZE;
225 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
226 info.align_offset = 0;
227 return vm_unmapped_area(&info);
228 }
229 #endif
230
231 static size_t
232 hugetlbfs_read_actor(struct page *page, unsigned long offset,
233 struct iov_iter *to, unsigned long size)
234 {
235 size_t copied = 0;
236 int i, chunksize;
237
238 /* Find which 4k chunk and offset with in that chunk */
239 i = offset >> PAGE_SHIFT;
240 offset = offset & ~PAGE_MASK;
241
242 while (size) {
243 size_t n;
244 chunksize = PAGE_SIZE;
245 if (offset)
246 chunksize -= offset;
247 if (chunksize > size)
248 chunksize = size;
249 n = copy_page_to_iter(&page[i], offset, chunksize, to);
250 copied += n;
251 if (n != chunksize)
252 return copied;
253 offset = 0;
254 size -= chunksize;
255 i++;
256 }
257 return copied;
258 }
259
260 /*
261 * Support for read() - Find the page attached to f_mapping and copy out the
262 * data. Its *very* similar to do_generic_mapping_read(), we can't use that
263 * since it has PAGE_SIZE assumptions.
264 */
265 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
266 {
267 struct file *file = iocb->ki_filp;
268 struct hstate *h = hstate_file(file);
269 struct address_space *mapping = file->f_mapping;
270 struct inode *inode = mapping->host;
271 unsigned long index = iocb->ki_pos >> huge_page_shift(h);
272 unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
273 unsigned long end_index;
274 loff_t isize;
275 ssize_t retval = 0;
276
277 while (iov_iter_count(to)) {
278 struct page *page;
279 size_t nr, copied;
280
281 /* nr is the maximum number of bytes to copy from this page */
282 nr = huge_page_size(h);
283 isize = i_size_read(inode);
284 if (!isize)
285 break;
286 end_index = (isize - 1) >> huge_page_shift(h);
287 if (index > end_index)
288 break;
289 if (index == end_index) {
290 nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
291 if (nr <= offset)
292 break;
293 }
294 nr = nr - offset;
295
296 /* Find the page */
297 page = find_lock_page(mapping, index);
298 if (unlikely(page == NULL)) {
299 /*
300 * We have a HOLE, zero out the user-buffer for the
301 * length of the hole or request.
302 */
303 copied = iov_iter_zero(nr, to);
304 } else {
305 unlock_page(page);
306
307 /*
308 * We have the page, copy it to user space buffer.
309 */
310 copied = hugetlbfs_read_actor(page, offset, to, nr);
311 put_page(page);
312 }
313 offset += copied;
314 retval += copied;
315 if (copied != nr && iov_iter_count(to)) {
316 if (!retval)
317 retval = -EFAULT;
318 break;
319 }
320 index += offset >> huge_page_shift(h);
321 offset &= ~huge_page_mask(h);
322 }
323 iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
324 return retval;
325 }
326
327 static int hugetlbfs_write_begin(struct file *file,
328 struct address_space *mapping,
329 loff_t pos, unsigned len, unsigned flags,
330 struct page **pagep, void **fsdata)
331 {
332 return -EINVAL;
333 }
334
335 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
336 loff_t pos, unsigned len, unsigned copied,
337 struct page *page, void *fsdata)
338 {
339 BUG();
340 return -EINVAL;
341 }
342
343 static void remove_huge_page(struct page *page)
344 {
345 ClearPageDirty(page);
346 ClearPageUptodate(page);
347 delete_from_page_cache(page);
348 }
349
350 static void
351 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end)
352 {
353 struct vm_area_struct *vma;
354
355 /*
356 * end == 0 indicates that the entire range after
357 * start should be unmapped.
358 */
359 vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
360 unsigned long v_offset;
361 unsigned long v_end;
362
363 /*
364 * Can the expression below overflow on 32-bit arches?
365 * No, because the interval tree returns us only those vmas
366 * which overlap the truncated area starting at pgoff,
367 * and no vma on a 32-bit arch can span beyond the 4GB.
368 */
369 if (vma->vm_pgoff < start)
370 v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
371 else
372 v_offset = 0;
373
374 if (!end)
375 v_end = vma->vm_end;
376 else {
377 v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
378 + vma->vm_start;
379 if (v_end > vma->vm_end)
380 v_end = vma->vm_end;
381 }
382
383 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
384 NULL);
385 }
386 }
387
388 /*
389 * remove_inode_hugepages handles two distinct cases: truncation and hole
390 * punch. There are subtle differences in operation for each case.
391 *
392 * truncation is indicated by end of range being LLONG_MAX
393 * In this case, we first scan the range and release found pages.
394 * After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
395 * maps and global counts. Page faults can not race with truncation
396 * in this routine. hugetlb_no_page() holds i_mmap_rwsem and prevents
397 * page faults in the truncated range by checking i_size. i_size is
398 * modified while holding i_mmap_rwsem.
399 * hole punch is indicated if end is not LLONG_MAX
400 * In the hole punch case we scan the range and release found pages.
401 * Only when releasing a page is the associated region/reserv map
402 * deleted. The region/reserv map for ranges without associated
403 * pages are not modified. Page faults can race with hole punch.
404 * This is indicated if we find a mapped page.
405 * Note: If the passed end of range value is beyond the end of file, but
406 * not LLONG_MAX this routine still performs a hole punch operation.
407 */
408 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
409 loff_t lend)
410 {
411 struct hstate *h = hstate_inode(inode);
412 struct address_space *mapping = &inode->i_data;
413 const pgoff_t start = lstart >> huge_page_shift(h);
414 const pgoff_t end = lend >> huge_page_shift(h);
415 struct vm_area_struct pseudo_vma;
416 struct pagevec pvec;
417 pgoff_t next, index;
418 int i, freed = 0;
419 bool truncate_op = (lend == LLONG_MAX);
420
421 vma_init(&pseudo_vma, current->mm);
422 pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
423 pagevec_init(&pvec);
424 next = start;
425 while (next < end) {
426 /*
427 * When no more pages are found, we are done.
428 */
429 if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
430 break;
431
432 for (i = 0; i < pagevec_count(&pvec); ++i) {
433 struct page *page = pvec.pages[i];
434 u32 hash;
435
436 index = page->index;
437 hash = hugetlb_fault_mutex_hash(mapping, index);
438 if (!truncate_op) {
439 /*
440 * Only need to hold the fault mutex in the
441 * hole punch case. This prevents races with
442 * page faults. Races are not possible in the
443 * case of truncation.
444 */
445 mutex_lock(&hugetlb_fault_mutex_table[hash]);
446 }
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 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
461 i_mmap_lock_write(mapping);
462 mutex_lock(&hugetlb_fault_mutex_table[hash]);
463 hugetlb_vmdelete_list(&mapping->i_mmap,
464 index * pages_per_huge_page(h),
465 (index + 1) * pages_per_huge_page(h));
466 i_mmap_unlock_write(mapping);
467 }
468
469 lock_page(page);
470 /*
471 * We must free the huge page and remove from page
472 * cache (remove_huge_page) BEFORE removing the
473 * region/reserve map (hugetlb_unreserve_pages). In
474 * rare out of memory conditions, removal of the
475 * region/reserve map could fail. Correspondingly,
476 * the subpool and global reserve usage count can need
477 * to be adjusted.
478 */
479 VM_BUG_ON(PagePrivate(page));
480 remove_huge_page(page);
481 freed++;
482 if (!truncate_op) {
483 if (unlikely(hugetlb_unreserve_pages(inode,
484 index, index + 1, 1)))
485 hugetlb_fix_reserve_counts(inode);
486 }
487
488 unlock_page(page);
489 if (!truncate_op)
490 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
491 }
492 huge_pagevec_release(&pvec);
493 cond_resched();
494 }
495
496 if (truncate_op)
497 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
498 }
499
500 static void hugetlbfs_evict_inode(struct inode *inode)
501 {
502 struct resv_map *resv_map;
503
504 remove_inode_hugepages(inode, 0, LLONG_MAX);
505
506 /*
507 * Get the resv_map from the address space embedded in the inode.
508 * This is the address space which points to any resv_map allocated
509 * at inode creation time. If this is a device special inode,
510 * i_mapping may not point to the original address space.
511 */
512 resv_map = (struct resv_map *)(&inode->i_data)->private_data;
513 /* Only regular and link inodes have associated reserve maps */
514 if (resv_map)
515 resv_map_release(&resv_map->refs);
516 clear_inode(inode);
517 }
518
519 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
520 {
521 pgoff_t pgoff;
522 struct address_space *mapping = inode->i_mapping;
523 struct hstate *h = hstate_inode(inode);
524
525 BUG_ON(offset & ~huge_page_mask(h));
526 pgoff = offset >> PAGE_SHIFT;
527
528 i_mmap_lock_write(mapping);
529 i_size_write(inode, offset);
530 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
531 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
532 i_mmap_unlock_write(mapping);
533 remove_inode_hugepages(inode, offset, LLONG_MAX);
534 return 0;
535 }
536
537 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
538 {
539 struct hstate *h = hstate_inode(inode);
540 loff_t hpage_size = huge_page_size(h);
541 loff_t hole_start, hole_end;
542
543 /*
544 * For hole punch round up the beginning offset of the hole and
545 * round down the end.
546 */
547 hole_start = round_up(offset, hpage_size);
548 hole_end = round_down(offset + len, hpage_size);
549
550 if (hole_end > hole_start) {
551 struct address_space *mapping = inode->i_mapping;
552 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
553
554 inode_lock(inode);
555
556 /* protected by i_mutex */
557 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
558 inode_unlock(inode);
559 return -EPERM;
560 }
561
562 i_mmap_lock_write(mapping);
563 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
564 hugetlb_vmdelete_list(&mapping->i_mmap,
565 hole_start >> PAGE_SHIFT,
566 hole_end >> PAGE_SHIFT);
567 i_mmap_unlock_write(mapping);
568 remove_inode_hugepages(inode, hole_start, hole_end);
569 inode_unlock(inode);
570 }
571
572 return 0;
573 }
574
575 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
576 loff_t len)
577 {
578 struct inode *inode = file_inode(file);
579 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
580 struct address_space *mapping = inode->i_mapping;
581 struct hstate *h = hstate_inode(inode);
582 struct vm_area_struct pseudo_vma;
583 struct mm_struct *mm = current->mm;
584 loff_t hpage_size = huge_page_size(h);
585 unsigned long hpage_shift = huge_page_shift(h);
586 pgoff_t start, index, end;
587 int error;
588 u32 hash;
589
590 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
591 return -EOPNOTSUPP;
592
593 if (mode & FALLOC_FL_PUNCH_HOLE)
594 return hugetlbfs_punch_hole(inode, offset, len);
595
596 /*
597 * Default preallocate case.
598 * For this range, start is rounded down and end is rounded up
599 * as well as being converted to page offsets.
600 */
601 start = offset >> hpage_shift;
602 end = (offset + len + hpage_size - 1) >> hpage_shift;
603
604 inode_lock(inode);
605
606 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
607 error = inode_newsize_ok(inode, offset + len);
608 if (error)
609 goto out;
610
611 if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
612 error = -EPERM;
613 goto out;
614 }
615
616 /*
617 * Initialize a pseudo vma as this is required by the huge page
618 * allocation routines. If NUMA is configured, use page index
619 * as input to create an allocation policy.
620 */
621 vma_init(&pseudo_vma, mm);
622 pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
623 pseudo_vma.vm_file = file;
624
625 for (index = start; index < end; index++) {
626 /*
627 * This is supposed to be the vaddr where the page is being
628 * faulted in, but we have no vaddr here.
629 */
630 struct page *page;
631 unsigned long addr;
632 int avoid_reserve = 0;
633
634 cond_resched();
635
636 /*
637 * fallocate(2) manpage permits EINTR; we may have been
638 * interrupted because we are using up too much memory.
639 */
640 if (signal_pending(current)) {
641 error = -EINTR;
642 break;
643 }
644
645 /* Set numa allocation policy based on index */
646 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
647
648 /* addr is the offset within the file (zero based) */
649 addr = index * hpage_size;
650
651 /*
652 * fault mutex taken here, protects against fault path
653 * and hole punch. inode_lock previously taken protects
654 * against truncation.
655 */
656 hash = hugetlb_fault_mutex_hash(mapping, index);
657 mutex_lock(&hugetlb_fault_mutex_table[hash]);
658
659 /* See if already present in mapping to avoid alloc/free */
660 page = find_get_page(mapping, index);
661 if (page) {
662 put_page(page);
663 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
664 hugetlb_drop_vma_policy(&pseudo_vma);
665 continue;
666 }
667
668 /* Allocate page and add to page cache */
669 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
670 hugetlb_drop_vma_policy(&pseudo_vma);
671 if (IS_ERR(page)) {
672 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
673 error = PTR_ERR(page);
674 goto out;
675 }
676 clear_huge_page(page, addr, pages_per_huge_page(h));
677 __SetPageUptodate(page);
678 error = huge_add_to_page_cache(page, mapping, index);
679 if (unlikely(error)) {
680 put_page(page);
681 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
682 goto out;
683 }
684
685 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
686
687 /*
688 * unlock_page because locked by add_to_page_cache()
689 * page_put due to reference from alloc_huge_page()
690 */
691 unlock_page(page);
692 put_page(page);
693 }
694
695 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
696 i_size_write(inode, offset + len);
697 inode->i_ctime = current_time(inode);
698 out:
699 inode_unlock(inode);
700 return error;
701 }
702
703 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
704 {
705 struct inode *inode = d_inode(dentry);
706 struct hstate *h = hstate_inode(inode);
707 int error;
708 unsigned int ia_valid = attr->ia_valid;
709 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
710
711 BUG_ON(!inode);
712
713 error = setattr_prepare(dentry, attr);
714 if (error)
715 return error;
716
717 if (ia_valid & ATTR_SIZE) {
718 loff_t oldsize = inode->i_size;
719 loff_t newsize = attr->ia_size;
720
721 if (newsize & ~huge_page_mask(h))
722 return -EINVAL;
723 /* protected by i_mutex */
724 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
725 (newsize > oldsize && (info->seals & F_SEAL_GROW)))
726 return -EPERM;
727 error = hugetlb_vmtruncate(inode, newsize);
728 if (error)
729 return error;
730 }
731
732 setattr_copy(inode, attr);
733 mark_inode_dirty(inode);
734 return 0;
735 }
736
737 static struct inode *hugetlbfs_get_root(struct super_block *sb,
738 struct hugetlbfs_fs_context *ctx)
739 {
740 struct inode *inode;
741
742 inode = new_inode(sb);
743 if (inode) {
744 inode->i_ino = get_next_ino();
745 inode->i_mode = S_IFDIR | ctx->mode;
746 inode->i_uid = ctx->uid;
747 inode->i_gid = ctx->gid;
748 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
749 inode->i_op = &hugetlbfs_dir_inode_operations;
750 inode->i_fop = &simple_dir_operations;
751 /* directory inodes start off with i_nlink == 2 (for "." entry) */
752 inc_nlink(inode);
753 lockdep_annotate_inode_mutex_key(inode);
754 }
755 return inode;
756 }
757
758 /*
759 * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
760 * be taken from reclaim -- unlike regular filesystems. This needs an
761 * annotation because huge_pmd_share() does an allocation under hugetlb's
762 * i_mmap_rwsem.
763 */
764 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
765
766 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
767 struct inode *dir,
768 umode_t mode, dev_t dev)
769 {
770 struct inode *inode;
771 struct resv_map *resv_map = NULL;
772
773 /*
774 * Reserve maps are only needed for inodes that can have associated
775 * page allocations.
776 */
777 if (S_ISREG(mode) || S_ISLNK(mode)) {
778 resv_map = resv_map_alloc();
779 if (!resv_map)
780 return NULL;
781 }
782
783 inode = new_inode(sb);
784 if (inode) {
785 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
786
787 inode->i_ino = get_next_ino();
788 inode_init_owner(inode, dir, mode);
789 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
790 &hugetlbfs_i_mmap_rwsem_key);
791 inode->i_mapping->a_ops = &hugetlbfs_aops;
792 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
793 inode->i_mapping->private_data = resv_map;
794 info->seals = F_SEAL_SEAL;
795 switch (mode & S_IFMT) {
796 default:
797 init_special_inode(inode, mode, dev);
798 break;
799 case S_IFREG:
800 inode->i_op = &hugetlbfs_inode_operations;
801 inode->i_fop = &hugetlbfs_file_operations;
802 break;
803 case S_IFDIR:
804 inode->i_op = &hugetlbfs_dir_inode_operations;
805 inode->i_fop = &simple_dir_operations;
806
807 /* directory inodes start off with i_nlink == 2 (for "." entry) */
808 inc_nlink(inode);
809 break;
810 case S_IFLNK:
811 inode->i_op = &page_symlink_inode_operations;
812 inode_nohighmem(inode);
813 break;
814 }
815 lockdep_annotate_inode_mutex_key(inode);
816 } else {
817 if (resv_map)
818 kref_put(&resv_map->refs, resv_map_release);
819 }
820
821 return inode;
822 }
823
824 /*
825 * File creation. Allocate an inode, and we're done..
826 */
827 static int do_hugetlbfs_mknod(struct inode *dir,
828 struct dentry *dentry,
829 umode_t mode,
830 dev_t dev,
831 bool tmpfile)
832 {
833 struct inode *inode;
834 int error = -ENOSPC;
835
836 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
837 if (inode) {
838 dir->i_ctime = dir->i_mtime = current_time(dir);
839 if (tmpfile) {
840 d_tmpfile(dentry, inode);
841 } else {
842 d_instantiate(dentry, inode);
843 dget(dentry);/* Extra count - pin the dentry in core */
844 }
845 error = 0;
846 }
847 return error;
848 }
849
850 static int hugetlbfs_mknod(struct inode *dir,
851 struct dentry *dentry, umode_t mode, dev_t dev)
852 {
853 return do_hugetlbfs_mknod(dir, dentry, mode, dev, false);
854 }
855
856 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
857 {
858 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
859 if (!retval)
860 inc_nlink(dir);
861 return retval;
862 }
863
864 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
865 {
866 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
867 }
868
869 static int hugetlbfs_tmpfile(struct inode *dir,
870 struct dentry *dentry, umode_t mode)
871 {
872 return do_hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0, true);
873 }
874
875 static int hugetlbfs_symlink(struct inode *dir,
876 struct dentry *dentry, const char *symname)
877 {
878 struct inode *inode;
879 int error = -ENOSPC;
880
881 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
882 if (inode) {
883 int l = strlen(symname)+1;
884 error = page_symlink(inode, symname, l);
885 if (!error) {
886 d_instantiate(dentry, inode);
887 dget(dentry);
888 } else
889 iput(inode);
890 }
891 dir->i_ctime = dir->i_mtime = current_time(dir);
892
893 return error;
894 }
895
896 /*
897 * mark the head page dirty
898 */
899 static int hugetlbfs_set_page_dirty(struct page *page)
900 {
901 struct page *head = compound_head(page);
902
903 SetPageDirty(head);
904 return 0;
905 }
906
907 static int hugetlbfs_migrate_page(struct address_space *mapping,
908 struct page *newpage, struct page *page,
909 enum migrate_mode mode)
910 {
911 int rc;
912
913 rc = migrate_huge_page_move_mapping(mapping, newpage, page);
914 if (rc != MIGRATEPAGE_SUCCESS)
915 return rc;
916
917 /*
918 * page_private is subpool pointer in hugetlb pages. Transfer to
919 * new page. PagePrivate is not associated with page_private for
920 * hugetlb pages and can not be set here as only page_huge_active
921 * pages can be migrated.
922 */
923 if (page_private(page)) {
924 set_page_private(newpage, page_private(page));
925 set_page_private(page, 0);
926 }
927
928 if (mode != MIGRATE_SYNC_NO_COPY)
929 migrate_page_copy(newpage, page);
930 else
931 migrate_page_states(newpage, page);
932
933 return MIGRATEPAGE_SUCCESS;
934 }
935
936 static int hugetlbfs_error_remove_page(struct address_space *mapping,
937 struct page *page)
938 {
939 struct inode *inode = mapping->host;
940 pgoff_t index = page->index;
941
942 remove_huge_page(page);
943 if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
944 hugetlb_fix_reserve_counts(inode);
945
946 return 0;
947 }
948
949 /*
950 * Display the mount options in /proc/mounts.
951 */
952 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
953 {
954 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
955 struct hugepage_subpool *spool = sbinfo->spool;
956 unsigned long hpage_size = huge_page_size(sbinfo->hstate);
957 unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
958 char mod;
959
960 if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
961 seq_printf(m, ",uid=%u",
962 from_kuid_munged(&init_user_ns, sbinfo->uid));
963 if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
964 seq_printf(m, ",gid=%u",
965 from_kgid_munged(&init_user_ns, sbinfo->gid));
966 if (sbinfo->mode != 0755)
967 seq_printf(m, ",mode=%o", sbinfo->mode);
968 if (sbinfo->max_inodes != -1)
969 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
970
971 hpage_size /= 1024;
972 mod = 'K';
973 if (hpage_size >= 1024) {
974 hpage_size /= 1024;
975 mod = 'M';
976 }
977 seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
978 if (spool) {
979 if (spool->max_hpages != -1)
980 seq_printf(m, ",size=%llu",
981 (unsigned long long)spool->max_hpages << hpage_shift);
982 if (spool->min_hpages != -1)
983 seq_printf(m, ",min_size=%llu",
984 (unsigned long long)spool->min_hpages << hpage_shift);
985 }
986 return 0;
987 }
988
989 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
990 {
991 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
992 struct hstate *h = hstate_inode(d_inode(dentry));
993
994 buf->f_type = HUGETLBFS_MAGIC;
995 buf->f_bsize = huge_page_size(h);
996 if (sbinfo) {
997 spin_lock(&sbinfo->stat_lock);
998 /* If no limits set, just report 0 for max/free/used
999 * blocks, like simple_statfs() */
1000 if (sbinfo->spool) {
1001 long free_pages;
1002
1003 spin_lock(&sbinfo->spool->lock);
1004 buf->f_blocks = sbinfo->spool->max_hpages;
1005 free_pages = sbinfo->spool->max_hpages
1006 - sbinfo->spool->used_hpages;
1007 buf->f_bavail = buf->f_bfree = free_pages;
1008 spin_unlock(&sbinfo->spool->lock);
1009 buf->f_files = sbinfo->max_inodes;
1010 buf->f_ffree = sbinfo->free_inodes;
1011 }
1012 spin_unlock(&sbinfo->stat_lock);
1013 }
1014 buf->f_namelen = NAME_MAX;
1015 return 0;
1016 }
1017
1018 static void hugetlbfs_put_super(struct super_block *sb)
1019 {
1020 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1021
1022 if (sbi) {
1023 sb->s_fs_info = NULL;
1024
1025 if (sbi->spool)
1026 hugepage_put_subpool(sbi->spool);
1027
1028 kfree(sbi);
1029 }
1030 }
1031
1032 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1033 {
1034 if (sbinfo->free_inodes >= 0) {
1035 spin_lock(&sbinfo->stat_lock);
1036 if (unlikely(!sbinfo->free_inodes)) {
1037 spin_unlock(&sbinfo->stat_lock);
1038 return 0;
1039 }
1040 sbinfo->free_inodes--;
1041 spin_unlock(&sbinfo->stat_lock);
1042 }
1043
1044 return 1;
1045 }
1046
1047 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1048 {
1049 if (sbinfo->free_inodes >= 0) {
1050 spin_lock(&sbinfo->stat_lock);
1051 sbinfo->free_inodes++;
1052 spin_unlock(&sbinfo->stat_lock);
1053 }
1054 }
1055
1056
1057 static struct kmem_cache *hugetlbfs_inode_cachep;
1058
1059 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1060 {
1061 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1062 struct hugetlbfs_inode_info *p;
1063
1064 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1065 return NULL;
1066 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
1067 if (unlikely(!p)) {
1068 hugetlbfs_inc_free_inodes(sbinfo);
1069 return NULL;
1070 }
1071
1072 /*
1073 * Any time after allocation, hugetlbfs_destroy_inode can be called
1074 * for the inode. mpol_free_shared_policy is unconditionally called
1075 * as part of hugetlbfs_destroy_inode. So, initialize policy here
1076 * in case of a quick call to destroy.
1077 *
1078 * Note that the policy is initialized even if we are creating a
1079 * private inode. This simplifies hugetlbfs_destroy_inode.
1080 */
1081 mpol_shared_policy_init(&p->policy, NULL);
1082
1083 return &p->vfs_inode;
1084 }
1085
1086 static void hugetlbfs_free_inode(struct inode *inode)
1087 {
1088 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1089 }
1090
1091 static void hugetlbfs_destroy_inode(struct inode *inode)
1092 {
1093 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1094 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1095 }
1096
1097 static const struct address_space_operations hugetlbfs_aops = {
1098 .write_begin = hugetlbfs_write_begin,
1099 .write_end = hugetlbfs_write_end,
1100 .set_page_dirty = hugetlbfs_set_page_dirty,
1101 .migratepage = hugetlbfs_migrate_page,
1102 .error_remove_page = hugetlbfs_error_remove_page,
1103 };
1104
1105
1106 static void init_once(void *foo)
1107 {
1108 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1109
1110 inode_init_once(&ei->vfs_inode);
1111 }
1112
1113 const struct file_operations hugetlbfs_file_operations = {
1114 .read_iter = hugetlbfs_read_iter,
1115 .mmap = hugetlbfs_file_mmap,
1116 .fsync = noop_fsync,
1117 .get_unmapped_area = hugetlb_get_unmapped_area,
1118 .llseek = default_llseek,
1119 .fallocate = hugetlbfs_fallocate,
1120 };
1121
1122 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1123 .create = hugetlbfs_create,
1124 .lookup = simple_lookup,
1125 .link = simple_link,
1126 .unlink = simple_unlink,
1127 .symlink = hugetlbfs_symlink,
1128 .mkdir = hugetlbfs_mkdir,
1129 .rmdir = simple_rmdir,
1130 .mknod = hugetlbfs_mknod,
1131 .rename = simple_rename,
1132 .setattr = hugetlbfs_setattr,
1133 .tmpfile = hugetlbfs_tmpfile,
1134 };
1135
1136 static const struct inode_operations hugetlbfs_inode_operations = {
1137 .setattr = hugetlbfs_setattr,
1138 };
1139
1140 static const struct super_operations hugetlbfs_ops = {
1141 .alloc_inode = hugetlbfs_alloc_inode,
1142 .free_inode = hugetlbfs_free_inode,
1143 .destroy_inode = hugetlbfs_destroy_inode,
1144 .evict_inode = hugetlbfs_evict_inode,
1145 .statfs = hugetlbfs_statfs,
1146 .put_super = hugetlbfs_put_super,
1147 .show_options = hugetlbfs_show_options,
1148 };
1149
1150 /*
1151 * Convert size option passed from command line to number of huge pages
1152 * in the pool specified by hstate. Size option could be in bytes
1153 * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1154 */
1155 static long
1156 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1157 enum hugetlbfs_size_type val_type)
1158 {
1159 if (val_type == NO_SIZE)
1160 return -1;
1161
1162 if (val_type == SIZE_PERCENT) {
1163 size_opt <<= huge_page_shift(h);
1164 size_opt *= h->max_huge_pages;
1165 do_div(size_opt, 100);
1166 }
1167
1168 size_opt >>= huge_page_shift(h);
1169 return size_opt;
1170 }
1171
1172 /*
1173 * Parse one mount parameter.
1174 */
1175 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1176 {
1177 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1178 struct fs_parse_result result;
1179 char *rest;
1180 unsigned long ps;
1181 int opt;
1182
1183 opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1184 if (opt < 0)
1185 return opt;
1186
1187 switch (opt) {
1188 case Opt_uid:
1189 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1190 if (!uid_valid(ctx->uid))
1191 goto bad_val;
1192 return 0;
1193
1194 case Opt_gid:
1195 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1196 if (!gid_valid(ctx->gid))
1197 goto bad_val;
1198 return 0;
1199
1200 case Opt_mode:
1201 ctx->mode = result.uint_32 & 01777U;
1202 return 0;
1203
1204 case Opt_size:
1205 /* memparse() will accept a K/M/G without a digit */
1206 if (!isdigit(param->string[0]))
1207 goto bad_val;
1208 ctx->max_size_opt = memparse(param->string, &rest);
1209 ctx->max_val_type = SIZE_STD;
1210 if (*rest == '%')
1211 ctx->max_val_type = SIZE_PERCENT;
1212 return 0;
1213
1214 case Opt_nr_inodes:
1215 /* memparse() will accept a K/M/G without a digit */
1216 if (!isdigit(param->string[0]))
1217 goto bad_val;
1218 ctx->nr_inodes = memparse(param->string, &rest);
1219 return 0;
1220
1221 case Opt_pagesize:
1222 ps = memparse(param->string, &rest);
1223 ctx->hstate = size_to_hstate(ps);
1224 if (!ctx->hstate) {
1225 pr_err("Unsupported page size %lu MB\n", ps >> 20);
1226 return -EINVAL;
1227 }
1228 return 0;
1229
1230 case Opt_min_size:
1231 /* memparse() will accept a K/M/G without a digit */
1232 if (!isdigit(param->string[0]))
1233 goto bad_val;
1234 ctx->min_size_opt = memparse(param->string, &rest);
1235 ctx->min_val_type = SIZE_STD;
1236 if (*rest == '%')
1237 ctx->min_val_type = SIZE_PERCENT;
1238 return 0;
1239
1240 default:
1241 return -EINVAL;
1242 }
1243
1244 bad_val:
1245 return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1246 param->string, param->key);
1247 }
1248
1249 /*
1250 * Validate the parsed options.
1251 */
1252 static int hugetlbfs_validate(struct fs_context *fc)
1253 {
1254 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1255
1256 /*
1257 * Use huge page pool size (in hstate) to convert the size
1258 * options to number of huge pages. If NO_SIZE, -1 is returned.
1259 */
1260 ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1261 ctx->max_size_opt,
1262 ctx->max_val_type);
1263 ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1264 ctx->min_size_opt,
1265 ctx->min_val_type);
1266
1267 /*
1268 * If max_size was specified, then min_size must be smaller
1269 */
1270 if (ctx->max_val_type > NO_SIZE &&
1271 ctx->min_hpages > ctx->max_hpages) {
1272 pr_err("Minimum size can not be greater than maximum size\n");
1273 return -EINVAL;
1274 }
1275
1276 return 0;
1277 }
1278
1279 static int
1280 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1281 {
1282 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1283 struct hugetlbfs_sb_info *sbinfo;
1284
1285 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1286 if (!sbinfo)
1287 return -ENOMEM;
1288 sb->s_fs_info = sbinfo;
1289 spin_lock_init(&sbinfo->stat_lock);
1290 sbinfo->hstate = ctx->hstate;
1291 sbinfo->max_inodes = ctx->nr_inodes;
1292 sbinfo->free_inodes = ctx->nr_inodes;
1293 sbinfo->spool = NULL;
1294 sbinfo->uid = ctx->uid;
1295 sbinfo->gid = ctx->gid;
1296 sbinfo->mode = ctx->mode;
1297
1298 /*
1299 * Allocate and initialize subpool if maximum or minimum size is
1300 * specified. Any needed reservations (for minimim size) are taken
1301 * taken when the subpool is created.
1302 */
1303 if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1304 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1305 ctx->max_hpages,
1306 ctx->min_hpages);
1307 if (!sbinfo->spool)
1308 goto out_free;
1309 }
1310 sb->s_maxbytes = MAX_LFS_FILESIZE;
1311 sb->s_blocksize = huge_page_size(ctx->hstate);
1312 sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1313 sb->s_magic = HUGETLBFS_MAGIC;
1314 sb->s_op = &hugetlbfs_ops;
1315 sb->s_time_gran = 1;
1316 sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1317 if (!sb->s_root)
1318 goto out_free;
1319 return 0;
1320 out_free:
1321 kfree(sbinfo->spool);
1322 kfree(sbinfo);
1323 return -ENOMEM;
1324 }
1325
1326 static int hugetlbfs_get_tree(struct fs_context *fc)
1327 {
1328 int err = hugetlbfs_validate(fc);
1329 if (err)
1330 return err;
1331 return get_tree_nodev(fc, hugetlbfs_fill_super);
1332 }
1333
1334 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1335 {
1336 kfree(fc->fs_private);
1337 }
1338
1339 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1340 .free = hugetlbfs_fs_context_free,
1341 .parse_param = hugetlbfs_parse_param,
1342 .get_tree = hugetlbfs_get_tree,
1343 };
1344
1345 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1346 {
1347 struct hugetlbfs_fs_context *ctx;
1348
1349 ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1350 if (!ctx)
1351 return -ENOMEM;
1352
1353 ctx->max_hpages = -1; /* No limit on size by default */
1354 ctx->nr_inodes = -1; /* No limit on number of inodes by default */
1355 ctx->uid = current_fsuid();
1356 ctx->gid = current_fsgid();
1357 ctx->mode = 0755;
1358 ctx->hstate = &default_hstate;
1359 ctx->min_hpages = -1; /* No default minimum size */
1360 ctx->max_val_type = NO_SIZE;
1361 ctx->min_val_type = NO_SIZE;
1362 fc->fs_private = ctx;
1363 fc->ops = &hugetlbfs_fs_context_ops;
1364 return 0;
1365 }
1366
1367 static struct file_system_type hugetlbfs_fs_type = {
1368 .name = "hugetlbfs",
1369 .init_fs_context = hugetlbfs_init_fs_context,
1370 .parameters = hugetlb_fs_parameters,
1371 .kill_sb = kill_litter_super,
1372 };
1373
1374 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1375
1376 static int can_do_hugetlb_shm(void)
1377 {
1378 kgid_t shm_group;
1379 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1380 return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1381 }
1382
1383 static int get_hstate_idx(int page_size_log)
1384 {
1385 struct hstate *h = hstate_sizelog(page_size_log);
1386
1387 if (!h)
1388 return -1;
1389 return h - hstates;
1390 }
1391
1392 /*
1393 * Note that size should be aligned to proper hugepage size in caller side,
1394 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1395 */
1396 struct file *hugetlb_file_setup(const char *name, size_t size,
1397 vm_flags_t acctflag, struct user_struct **user,
1398 int creat_flags, int page_size_log)
1399 {
1400 struct inode *inode;
1401 struct vfsmount *mnt;
1402 int hstate_idx;
1403 struct file *file;
1404
1405 hstate_idx = get_hstate_idx(page_size_log);
1406 if (hstate_idx < 0)
1407 return ERR_PTR(-ENODEV);
1408
1409 *user = NULL;
1410 mnt = hugetlbfs_vfsmount[hstate_idx];
1411 if (!mnt)
1412 return ERR_PTR(-ENOENT);
1413
1414 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1415 *user = current_user();
1416 if (user_shm_lock(size, *user)) {
1417 task_lock(current);
1418 pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1419 current->comm, current->pid);
1420 task_unlock(current);
1421 } else {
1422 *user = NULL;
1423 return ERR_PTR(-EPERM);
1424 }
1425 }
1426
1427 file = ERR_PTR(-ENOSPC);
1428 inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1429 if (!inode)
1430 goto out;
1431 if (creat_flags == HUGETLB_SHMFS_INODE)
1432 inode->i_flags |= S_PRIVATE;
1433
1434 inode->i_size = size;
1435 clear_nlink(inode);
1436
1437 if (hugetlb_reserve_pages(inode, 0,
1438 size >> huge_page_shift(hstate_inode(inode)), NULL,
1439 acctflag))
1440 file = ERR_PTR(-ENOMEM);
1441 else
1442 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1443 &hugetlbfs_file_operations);
1444 if (!IS_ERR(file))
1445 return file;
1446
1447 iput(inode);
1448 out:
1449 if (*user) {
1450 user_shm_unlock(size, *user);
1451 *user = NULL;
1452 }
1453 return file;
1454 }
1455
1456 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1457 {
1458 struct fs_context *fc;
1459 struct vfsmount *mnt;
1460
1461 fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1462 if (IS_ERR(fc)) {
1463 mnt = ERR_CAST(fc);
1464 } else {
1465 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1466 ctx->hstate = h;
1467 mnt = fc_mount(fc);
1468 put_fs_context(fc);
1469 }
1470 if (IS_ERR(mnt))
1471 pr_err("Cannot mount internal hugetlbfs for page size %uK",
1472 1U << (h->order + PAGE_SHIFT - 10));
1473 return mnt;
1474 }
1475
1476 static int __init init_hugetlbfs_fs(void)
1477 {
1478 struct vfsmount *mnt;
1479 struct hstate *h;
1480 int error;
1481 int i;
1482
1483 if (!hugepages_supported()) {
1484 pr_info("disabling because there are no supported hugepage sizes\n");
1485 return -ENOTSUPP;
1486 }
1487
1488 error = -ENOMEM;
1489 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1490 sizeof(struct hugetlbfs_inode_info),
1491 0, SLAB_ACCOUNT, init_once);
1492 if (hugetlbfs_inode_cachep == NULL)
1493 goto out;
1494
1495 error = register_filesystem(&hugetlbfs_fs_type);
1496 if (error)
1497 goto out_free;
1498
1499 /* default hstate mount is required */
1500 mnt = mount_one_hugetlbfs(&hstates[default_hstate_idx]);
1501 if (IS_ERR(mnt)) {
1502 error = PTR_ERR(mnt);
1503 goto out_unreg;
1504 }
1505 hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1506
1507 /* other hstates are optional */
1508 i = 0;
1509 for_each_hstate(h) {
1510 if (i == default_hstate_idx) {
1511 i++;
1512 continue;
1513 }
1514
1515 mnt = mount_one_hugetlbfs(h);
1516 if (IS_ERR(mnt))
1517 hugetlbfs_vfsmount[i] = NULL;
1518 else
1519 hugetlbfs_vfsmount[i] = mnt;
1520 i++;
1521 }
1522
1523 return 0;
1524
1525 out_unreg:
1526 (void)unregister_filesystem(&hugetlbfs_fs_type);
1527 out_free:
1528 kmem_cache_destroy(hugetlbfs_inode_cachep);
1529 out:
1530 return error;
1531 }
1532 fs_initcall(init_hugetlbfs_fs)
Linux with added FPC-III support