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/falloc.h>
15 #include <linux/fs.h>
16 #include <linux/mount.h>
17 #include <linux/file.h>
18 #include <linux/kernel.h>
19 #include <linux/writeback.h>
20 #include <linux/pagemap.h>
21 #include <linux/highmem.h>
22 #include <linux/init.h>
23 #include <linux/string.h>
24 #include <linux/capability.h>
25 #include <linux/ctype.h>
26 #include <linux/backing-dev.h>
27 #include <linux/hugetlb.h>
28 #include <linux/pagevec.h>
29 #include <linux/fs_parser.h>
30 #include <linux/mman.h>
31 #include <linux/slab.h>
32 #include <linux/dnotify.h>
33 #include <linux/statfs.h>
34 #include <linux/security.h>
35 #include <linux/magic.h>
36 #include <linux/migrate.h>
37 #include <linux/uio.h>
38
39 #include <linux/uaccess.h>
40 #include <linux/sched/mm.h>
41
42 static const struct address_space_operations hugetlbfs_aops;
43 static const struct file_operations hugetlbfs_file_operations;
44 static const struct inode_operations hugetlbfs_dir_inode_operations;
45 static const struct inode_operations hugetlbfs_inode_operations;
46
47 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
48
49 struct hugetlbfs_fs_context {
50 struct hstate *hstate;
51 unsigned long long max_size_opt;
52 unsigned long long min_size_opt;
53 long max_hpages;
54 long nr_inodes;
55 long min_hpages;
56 enum hugetlbfs_size_type max_val_type;
57 enum hugetlbfs_size_type min_val_type;
58 kuid_t uid;
59 kgid_t gid;
60 umode_t mode;
61 };
62
63 int sysctl_hugetlb_shm_group;
64
65 enum hugetlb_param {
66 Opt_gid,
67 Opt_min_size,
68 Opt_mode,
69 Opt_nr_inodes,
70 Opt_pagesize,
71 Opt_size,
72 Opt_uid,
73 };
74
75 static const struct fs_parameter_spec hugetlb_fs_parameters[] = {
76 fsparam_u32 ("gid", Opt_gid),
77 fsparam_string("min_size", Opt_min_size),
78 fsparam_u32oct("mode", Opt_mode),
79 fsparam_string("nr_inodes", Opt_nr_inodes),
80 fsparam_string("pagesize", Opt_pagesize),
81 fsparam_string("size", Opt_size),
82 fsparam_u32 ("uid", Opt_uid),
83 {}
84 };
85
86 /*
87 * Mask used when checking the page offset value passed in via system
88 * calls. This value will be converted to a loff_t which is signed.
89 * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
90 * value. The extra bit (- 1 in the shift value) is to take the sign
91 * bit into account.
92 */
93 #define PGOFF_LOFFT_MAX \
94 (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1)))
95
hugetlbfs_file_mmap(struct file * file,struct vm_area_struct * vma)96 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
97 {
98 struct inode *inode = file_inode(file);
99 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
100 loff_t len, vma_len;
101 int ret;
102 struct hstate *h = hstate_file(file);
103 vm_flags_t vm_flags;
104
105 /*
106 * vma address alignment (but not the pgoff alignment) has
107 * already been checked by prepare_hugepage_range. If you add
108 * any error returns here, do so after setting VM_HUGETLB, so
109 * is_vm_hugetlb_page tests below unmap_region go the right
110 * way when do_mmap unwinds (may be important on powerpc
111 * and ia64).
112 */
113 vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND);
114 vma->vm_ops = &hugetlb_vm_ops;
115
116 ret = seal_check_write(info->seals, vma);
117 if (ret)
118 return ret;
119
120 /*
121 * page based offset in vm_pgoff could be sufficiently large to
122 * overflow a loff_t when converted to byte offset. This can
123 * only happen on architectures where sizeof(loff_t) ==
124 * sizeof(unsigned long). So, only check in those instances.
125 */
126 if (sizeof(unsigned long) == sizeof(loff_t)) {
127 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
128 return -EINVAL;
129 }
130
131 /* must be huge page aligned */
132 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
133 return -EINVAL;
134
135 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
136 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
137 /* check for overflow */
138 if (len < vma_len)
139 return -EINVAL;
140
141 inode_lock(inode);
142 file_accessed(file);
143
144 ret = -ENOMEM;
145
146 vm_flags = vma->vm_flags;
147 /*
148 * for SHM_HUGETLB, the pages are reserved in the shmget() call so skip
149 * reserving here. Note: only for SHM hugetlbfs file, the inode
150 * flag S_PRIVATE is set.
151 */
152 if (inode->i_flags & S_PRIVATE)
153 vm_flags |= VM_NORESERVE;
154
155 if (!hugetlb_reserve_pages(inode,
156 vma->vm_pgoff >> huge_page_order(h),
157 len >> huge_page_shift(h), vma,
158 vm_flags))
159 goto out;
160
161 ret = 0;
162 if (vma->vm_flags & VM_WRITE && inode->i_size < len)
163 i_size_write(inode, len);
164 out:
165 inode_unlock(inode);
166
167 return ret;
168 }
169
170 /*
171 * Called under mmap_write_lock(mm).
172 */
173
174 static unsigned long
hugetlb_get_unmapped_area_bottomup(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)175 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
176 unsigned long len, unsigned long pgoff, unsigned long flags)
177 {
178 struct hstate *h = hstate_file(file);
179 struct vm_unmapped_area_info info = {};
180
181 info.length = len;
182 info.low_limit = current->mm->mmap_base;
183 info.high_limit = arch_get_mmap_end(addr, len, flags);
184 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
185 return vm_unmapped_area(&info);
186 }
187
188 static unsigned long
hugetlb_get_unmapped_area_topdown(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)189 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
190 unsigned long len, unsigned long pgoff, unsigned long flags)
191 {
192 struct hstate *h = hstate_file(file);
193 struct vm_unmapped_area_info info = {};
194
195 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
196 info.length = len;
197 info.low_limit = PAGE_SIZE;
198 info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
199 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
200 addr = vm_unmapped_area(&info);
201
202 /*
203 * A failed mmap() very likely causes application failure,
204 * so fall back to the bottom-up function here. This scenario
205 * can happen with large stack limits and large mmap()
206 * allocations.
207 */
208 if (unlikely(offset_in_page(addr))) {
209 VM_BUG_ON(addr != -ENOMEM);
210 info.flags = 0;
211 info.low_limit = current->mm->mmap_base;
212 info.high_limit = arch_get_mmap_end(addr, len, flags);
213 addr = vm_unmapped_area(&info);
214 }
215
216 return addr;
217 }
218
219 unsigned long
generic_hugetlb_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)220 generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
221 unsigned long len, unsigned long pgoff,
222 unsigned long flags)
223 {
224 struct mm_struct *mm = current->mm;
225 struct vm_area_struct *vma;
226 struct hstate *h = hstate_file(file);
227 const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
228
229 if (len & ~huge_page_mask(h))
230 return -EINVAL;
231 if (len > TASK_SIZE)
232 return -ENOMEM;
233
234 if (flags & MAP_FIXED) {
235 if (prepare_hugepage_range(file, addr, len))
236 return -EINVAL;
237 return addr;
238 }
239
240 if (addr) {
241 addr = ALIGN(addr, huge_page_size(h));
242 vma = find_vma(mm, addr);
243 if (mmap_end - len >= addr &&
244 (!vma || addr + len <= vm_start_gap(vma)))
245 return addr;
246 }
247
248 /*
249 * Use MMF_TOPDOWN flag as a hint to use topdown routine.
250 * If architectures have special needs, they should define their own
251 * version of hugetlb_get_unmapped_area.
252 */
253 if (test_bit(MMF_TOPDOWN, &mm->flags))
254 return hugetlb_get_unmapped_area_topdown(file, addr, len,
255 pgoff, flags);
256 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
257 pgoff, flags);
258 }
259
260 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
261 static unsigned long
hugetlb_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)262 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
263 unsigned long len, unsigned long pgoff,
264 unsigned long flags)
265 {
266 return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
267 }
268 #endif
269
270 /*
271 * Someone wants to read @bytes from a HWPOISON hugetlb @page from @offset.
272 * Returns the maximum number of bytes one can read without touching the 1st raw
273 * HWPOISON subpage.
274 *
275 * The implementation borrows the iteration logic from copy_page_to_iter*.
276 */
adjust_range_hwpoison(struct page * page,size_t offset,size_t bytes)277 static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t bytes)
278 {
279 size_t n = 0;
280 size_t res = 0;
281
282 /* First subpage to start the loop. */
283 page = nth_page(page, offset / PAGE_SIZE);
284 offset %= PAGE_SIZE;
285 while (1) {
286 if (is_raw_hwpoison_page_in_hugepage(page))
287 break;
288
289 /* Safe to read n bytes without touching HWPOISON subpage. */
290 n = min(bytes, (size_t)PAGE_SIZE - offset);
291 res += n;
292 bytes -= n;
293 if (!bytes || !n)
294 break;
295 offset += n;
296 if (offset == PAGE_SIZE) {
297 page = nth_page(page, 1);
298 offset = 0;
299 }
300 }
301
302 return res;
303 }
304
305 /*
306 * Support for read() - Find the page attached to f_mapping and copy out the
307 * data. This provides functionality similar to filemap_read().
308 */
hugetlbfs_read_iter(struct kiocb * iocb,struct iov_iter * to)309 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
310 {
311 struct file *file = iocb->ki_filp;
312 struct hstate *h = hstate_file(file);
313 struct address_space *mapping = file->f_mapping;
314 struct inode *inode = mapping->host;
315 unsigned long index = iocb->ki_pos >> huge_page_shift(h);
316 unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
317 unsigned long end_index;
318 loff_t isize;
319 ssize_t retval = 0;
320
321 while (iov_iter_count(to)) {
322 struct folio *folio;
323 size_t nr, copied, want;
324
325 /* nr is the maximum number of bytes to copy from this page */
326 nr = huge_page_size(h);
327 isize = i_size_read(inode);
328 if (!isize)
329 break;
330 end_index = (isize - 1) >> huge_page_shift(h);
331 if (index > end_index)
332 break;
333 if (index == end_index) {
334 nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
335 if (nr <= offset)
336 break;
337 }
338 nr = nr - offset;
339
340 /* Find the folio */
341 folio = filemap_lock_hugetlb_folio(h, mapping, index);
342 if (IS_ERR(folio)) {
343 /*
344 * We have a HOLE, zero out the user-buffer for the
345 * length of the hole or request.
346 */
347 copied = iov_iter_zero(nr, to);
348 } else {
349 folio_unlock(folio);
350
351 if (!folio_test_hwpoison(folio))
352 want = nr;
353 else {
354 /*
355 * Adjust how many bytes safe to read without
356 * touching the 1st raw HWPOISON subpage after
357 * offset.
358 */
359 want = adjust_range_hwpoison(&folio->page, offset, nr);
360 if (want == 0) {
361 folio_put(folio);
362 retval = -EIO;
363 break;
364 }
365 }
366
367 /*
368 * We have the folio, copy it to user space buffer.
369 */
370 copied = copy_folio_to_iter(folio, offset, want, to);
371 folio_put(folio);
372 }
373 offset += copied;
374 retval += copied;
375 if (copied != nr && iov_iter_count(to)) {
376 if (!retval)
377 retval = -EFAULT;
378 break;
379 }
380 index += offset >> huge_page_shift(h);
381 offset &= ~huge_page_mask(h);
382 }
383 iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
384 return retval;
385 }
386
hugetlbfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)387 static int hugetlbfs_write_begin(struct file *file,
388 struct address_space *mapping,
389 loff_t pos, unsigned len,
390 struct page **pagep, void **fsdata)
391 {
392 return -EINVAL;
393 }
394
hugetlbfs_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)395 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
396 loff_t pos, unsigned len, unsigned copied,
397 struct page *page, void *fsdata)
398 {
399 BUG();
400 return -EINVAL;
401 }
402
hugetlb_delete_from_page_cache(struct folio * folio)403 static void hugetlb_delete_from_page_cache(struct folio *folio)
404 {
405 folio_clear_dirty(folio);
406 folio_clear_uptodate(folio);
407 filemap_remove_folio(folio);
408 }
409
410 /*
411 * Called with i_mmap_rwsem held for inode based vma maps. This makes
412 * sure vma (and vm_mm) will not go away. We also hold the hugetlb fault
413 * mutex for the page in the mapping. So, we can not race with page being
414 * faulted into the vma.
415 */
hugetlb_vma_maps_page(struct vm_area_struct * vma,unsigned long addr,struct page * page)416 static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
417 unsigned long addr, struct page *page)
418 {
419 pte_t *ptep, pte;
420
421 ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma)));
422 if (!ptep)
423 return false;
424
425 pte = huge_ptep_get(ptep);
426 if (huge_pte_none(pte) || !pte_present(pte))
427 return false;
428
429 if (pte_page(pte) == page)
430 return true;
431
432 return false;
433 }
434
435 /*
436 * Can vma_offset_start/vma_offset_end overflow on 32-bit arches?
437 * No, because the interval tree returns us only those vmas
438 * which overlap the truncated area starting at pgoff,
439 * and no vma on a 32-bit arch can span beyond the 4GB.
440 */
vma_offset_start(struct vm_area_struct * vma,pgoff_t start)441 static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start)
442 {
443 unsigned long offset = 0;
444
445 if (vma->vm_pgoff < start)
446 offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
447
448 return vma->vm_start + offset;
449 }
450
vma_offset_end(struct vm_area_struct * vma,pgoff_t end)451 static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end)
452 {
453 unsigned long t_end;
454
455 if (!end)
456 return vma->vm_end;
457
458 t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start;
459 if (t_end > vma->vm_end)
460 t_end = vma->vm_end;
461 return t_end;
462 }
463
464 /*
465 * Called with hugetlb fault mutex held. Therefore, no more mappings to
466 * this folio can be created while executing the routine.
467 */
hugetlb_unmap_file_folio(struct hstate * h,struct address_space * mapping,struct folio * folio,pgoff_t index)468 static void hugetlb_unmap_file_folio(struct hstate *h,
469 struct address_space *mapping,
470 struct folio *folio, pgoff_t index)
471 {
472 struct rb_root_cached *root = &mapping->i_mmap;
473 struct hugetlb_vma_lock *vma_lock;
474 struct page *page = &folio->page;
475 struct vm_area_struct *vma;
476 unsigned long v_start;
477 unsigned long v_end;
478 pgoff_t start, end;
479
480 start = index * pages_per_huge_page(h);
481 end = (index + 1) * pages_per_huge_page(h);
482
483 i_mmap_lock_write(mapping);
484 retry:
485 vma_lock = NULL;
486 vma_interval_tree_foreach(vma, root, start, end - 1) {
487 v_start = vma_offset_start(vma, start);
488 v_end = vma_offset_end(vma, end);
489
490 if (!hugetlb_vma_maps_page(vma, v_start, page))
491 continue;
492
493 if (!hugetlb_vma_trylock_write(vma)) {
494 vma_lock = vma->vm_private_data;
495 /*
496 * If we can not get vma lock, we need to drop
497 * immap_sema and take locks in order. First,
498 * take a ref on the vma_lock structure so that
499 * we can be guaranteed it will not go away when
500 * dropping immap_sema.
501 */
502 kref_get(&vma_lock->refs);
503 break;
504 }
505
506 unmap_hugepage_range(vma, v_start, v_end, NULL,
507 ZAP_FLAG_DROP_MARKER);
508 hugetlb_vma_unlock_write(vma);
509 }
510
511 i_mmap_unlock_write(mapping);
512
513 if (vma_lock) {
514 /*
515 * Wait on vma_lock. We know it is still valid as we have
516 * a reference. We must 'open code' vma locking as we do
517 * not know if vma_lock is still attached to vma.
518 */
519 down_write(&vma_lock->rw_sema);
520 i_mmap_lock_write(mapping);
521
522 vma = vma_lock->vma;
523 if (!vma) {
524 /*
525 * If lock is no longer attached to vma, then just
526 * unlock, drop our reference and retry looking for
527 * other vmas.
528 */
529 up_write(&vma_lock->rw_sema);
530 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
531 goto retry;
532 }
533
534 /*
535 * vma_lock is still attached to vma. Check to see if vma
536 * still maps page and if so, unmap.
537 */
538 v_start = vma_offset_start(vma, start);
539 v_end = vma_offset_end(vma, end);
540 if (hugetlb_vma_maps_page(vma, v_start, page))
541 unmap_hugepage_range(vma, v_start, v_end, NULL,
542 ZAP_FLAG_DROP_MARKER);
543
544 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
545 hugetlb_vma_unlock_write(vma);
546
547 goto retry;
548 }
549 }
550
551 static void
hugetlb_vmdelete_list(struct rb_root_cached * root,pgoff_t start,pgoff_t end,zap_flags_t zap_flags)552 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
553 zap_flags_t zap_flags)
554 {
555 struct vm_area_struct *vma;
556
557 /*
558 * end == 0 indicates that the entire range after start should be
559 * unmapped. Note, end is exclusive, whereas the interval tree takes
560 * an inclusive "last".
561 */
562 vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
563 unsigned long v_start;
564 unsigned long v_end;
565
566 if (!hugetlb_vma_trylock_write(vma))
567 continue;
568
569 v_start = vma_offset_start(vma, start);
570 v_end = vma_offset_end(vma, end);
571
572 unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags);
573
574 /*
575 * Note that vma lock only exists for shared/non-private
576 * vmas. Therefore, lock is not held when calling
577 * unmap_hugepage_range for private vmas.
578 */
579 hugetlb_vma_unlock_write(vma);
580 }
581 }
582
583 /*
584 * Called with hugetlb fault mutex held.
585 * Returns true if page was actually removed, false otherwise.
586 */
remove_inode_single_folio(struct hstate * h,struct inode * inode,struct address_space * mapping,struct folio * folio,pgoff_t index,bool truncate_op)587 static bool remove_inode_single_folio(struct hstate *h, struct inode *inode,
588 struct address_space *mapping,
589 struct folio *folio, pgoff_t index,
590 bool truncate_op)
591 {
592 bool ret = false;
593
594 /*
595 * If folio is mapped, it was faulted in after being
596 * unmapped in caller. Unmap (again) while holding
597 * the fault mutex. The mutex will prevent faults
598 * until we finish removing the folio.
599 */
600 if (unlikely(folio_mapped(folio)))
601 hugetlb_unmap_file_folio(h, mapping, folio, index);
602
603 folio_lock(folio);
604 /*
605 * We must remove the folio from page cache before removing
606 * the region/ reserve map (hugetlb_unreserve_pages). In
607 * rare out of memory conditions, removal of the region/reserve
608 * map could fail. Correspondingly, the subpool and global
609 * reserve usage count can need to be adjusted.
610 */
611 VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio);
612 hugetlb_delete_from_page_cache(folio);
613 ret = true;
614 if (!truncate_op) {
615 if (unlikely(hugetlb_unreserve_pages(inode, index,
616 index + 1, 1)))
617 hugetlb_fix_reserve_counts(inode);
618 }
619
620 folio_unlock(folio);
621 return ret;
622 }
623
624 /*
625 * remove_inode_hugepages handles two distinct cases: truncation and hole
626 * punch. There are subtle differences in operation for each case.
627 *
628 * truncation is indicated by end of range being LLONG_MAX
629 * In this case, we first scan the range and release found pages.
630 * After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
631 * maps and global counts. Page faults can race with truncation.
632 * During faults, hugetlb_no_page() checks i_size before page allocation,
633 * and again after obtaining page table lock. It will 'back out'
634 * allocations in the truncated range.
635 * hole punch is indicated if end is not LLONG_MAX
636 * In the hole punch case we scan the range and release found pages.
637 * Only when releasing a page is the associated region/reserve map
638 * deleted. The region/reserve map for ranges without associated
639 * pages are not modified. Page faults can race with hole punch.
640 * This is indicated if we find a mapped page.
641 * Note: If the passed end of range value is beyond the end of file, but
642 * not LLONG_MAX this routine still performs a hole punch operation.
643 */
remove_inode_hugepages(struct inode * inode,loff_t lstart,loff_t lend)644 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
645 loff_t lend)
646 {
647 struct hstate *h = hstate_inode(inode);
648 struct address_space *mapping = &inode->i_data;
649 const pgoff_t end = lend >> PAGE_SHIFT;
650 struct folio_batch fbatch;
651 pgoff_t next, index;
652 int i, freed = 0;
653 bool truncate_op = (lend == LLONG_MAX);
654
655 folio_batch_init(&fbatch);
656 next = lstart >> PAGE_SHIFT;
657 while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) {
658 for (i = 0; i < folio_batch_count(&fbatch); ++i) {
659 struct folio *folio = fbatch.folios[i];
660 u32 hash = 0;
661
662 index = folio->index >> huge_page_order(h);
663 hash = hugetlb_fault_mutex_hash(mapping, index);
664 mutex_lock(&hugetlb_fault_mutex_table[hash]);
665
666 /*
667 * Remove folio that was part of folio_batch.
668 */
669 if (remove_inode_single_folio(h, inode, mapping, folio,
670 index, truncate_op))
671 freed++;
672
673 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
674 }
675 folio_batch_release(&fbatch);
676 cond_resched();
677 }
678
679 if (truncate_op)
680 (void)hugetlb_unreserve_pages(inode,
681 lstart >> huge_page_shift(h),
682 LONG_MAX, freed);
683 }
684
hugetlbfs_evict_inode(struct inode * inode)685 static void hugetlbfs_evict_inode(struct inode *inode)
686 {
687 struct resv_map *resv_map;
688
689 remove_inode_hugepages(inode, 0, LLONG_MAX);
690
691 /*
692 * Get the resv_map from the address space embedded in the inode.
693 * This is the address space which points to any resv_map allocated
694 * at inode creation time. If this is a device special inode,
695 * i_mapping may not point to the original address space.
696 */
697 resv_map = (struct resv_map *)(&inode->i_data)->i_private_data;
698 /* Only regular and link inodes have associated reserve maps */
699 if (resv_map)
700 resv_map_release(&resv_map->refs);
701 clear_inode(inode);
702 }
703
hugetlb_vmtruncate(struct inode * inode,loff_t offset)704 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
705 {
706 pgoff_t pgoff;
707 struct address_space *mapping = inode->i_mapping;
708 struct hstate *h = hstate_inode(inode);
709
710 BUG_ON(offset & ~huge_page_mask(h));
711 pgoff = offset >> PAGE_SHIFT;
712
713 i_size_write(inode, offset);
714 i_mmap_lock_write(mapping);
715 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
716 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
717 ZAP_FLAG_DROP_MARKER);
718 i_mmap_unlock_write(mapping);
719 remove_inode_hugepages(inode, offset, LLONG_MAX);
720 }
721
hugetlbfs_zero_partial_page(struct hstate * h,struct address_space * mapping,loff_t start,loff_t end)722 static void hugetlbfs_zero_partial_page(struct hstate *h,
723 struct address_space *mapping,
724 loff_t start,
725 loff_t end)
726 {
727 pgoff_t idx = start >> huge_page_shift(h);
728 struct folio *folio;
729
730 folio = filemap_lock_hugetlb_folio(h, mapping, idx);
731 if (IS_ERR(folio))
732 return;
733
734 start = start & ~huge_page_mask(h);
735 end = end & ~huge_page_mask(h);
736 if (!end)
737 end = huge_page_size(h);
738
739 folio_zero_segment(folio, (size_t)start, (size_t)end);
740
741 folio_unlock(folio);
742 folio_put(folio);
743 }
744
hugetlbfs_punch_hole(struct inode * inode,loff_t offset,loff_t len)745 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
746 {
747 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
748 struct address_space *mapping = inode->i_mapping;
749 struct hstate *h = hstate_inode(inode);
750 loff_t hpage_size = huge_page_size(h);
751 loff_t hole_start, hole_end;
752
753 /*
754 * hole_start and hole_end indicate the full pages within the hole.
755 */
756 hole_start = round_up(offset, hpage_size);
757 hole_end = round_down(offset + len, hpage_size);
758
759 inode_lock(inode);
760
761 /* protected by i_rwsem */
762 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
763 inode_unlock(inode);
764 return -EPERM;
765 }
766
767 i_mmap_lock_write(mapping);
768
769 /* If range starts before first full page, zero partial page. */
770 if (offset < hole_start)
771 hugetlbfs_zero_partial_page(h, mapping,
772 offset, min(offset + len, hole_start));
773
774 /* Unmap users of full pages in the hole. */
775 if (hole_end > hole_start) {
776 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
777 hugetlb_vmdelete_list(&mapping->i_mmap,
778 hole_start >> PAGE_SHIFT,
779 hole_end >> PAGE_SHIFT, 0);
780 }
781
782 /* If range extends beyond last full page, zero partial page. */
783 if ((offset + len) > hole_end && (offset + len) > hole_start)
784 hugetlbfs_zero_partial_page(h, mapping,
785 hole_end, offset + len);
786
787 i_mmap_unlock_write(mapping);
788
789 /* Remove full pages from the file. */
790 if (hole_end > hole_start)
791 remove_inode_hugepages(inode, hole_start, hole_end);
792
793 inode_unlock(inode);
794
795 return 0;
796 }
797
hugetlbfs_fallocate(struct file * file,int mode,loff_t offset,loff_t len)798 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
799 loff_t len)
800 {
801 struct inode *inode = file_inode(file);
802 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
803 struct address_space *mapping = inode->i_mapping;
804 struct hstate *h = hstate_inode(inode);
805 struct vm_area_struct pseudo_vma;
806 struct mm_struct *mm = current->mm;
807 loff_t hpage_size = huge_page_size(h);
808 unsigned long hpage_shift = huge_page_shift(h);
809 pgoff_t start, index, end;
810 int error;
811 u32 hash;
812
813 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
814 return -EOPNOTSUPP;
815
816 if (mode & FALLOC_FL_PUNCH_HOLE)
817 return hugetlbfs_punch_hole(inode, offset, len);
818
819 /*
820 * Default preallocate case.
821 * For this range, start is rounded down and end is rounded up
822 * as well as being converted to page offsets.
823 */
824 start = offset >> hpage_shift;
825 end = (offset + len + hpage_size - 1) >> hpage_shift;
826
827 inode_lock(inode);
828
829 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
830 error = inode_newsize_ok(inode, offset + len);
831 if (error)
832 goto out;
833
834 if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
835 error = -EPERM;
836 goto out;
837 }
838
839 /*
840 * Initialize a pseudo vma as this is required by the huge page
841 * allocation routines.
842 */
843 vma_init(&pseudo_vma, mm);
844 vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
845 pseudo_vma.vm_file = file;
846
847 for (index = start; index < end; index++) {
848 /*
849 * This is supposed to be the vaddr where the page is being
850 * faulted in, but we have no vaddr here.
851 */
852 struct folio *folio;
853 unsigned long addr;
854
855 cond_resched();
856
857 /*
858 * fallocate(2) manpage permits EINTR; we may have been
859 * interrupted because we are using up too much memory.
860 */
861 if (signal_pending(current)) {
862 error = -EINTR;
863 break;
864 }
865
866 /* addr is the offset within the file (zero based) */
867 addr = index * hpage_size;
868
869 /* mutex taken here, fault path and hole punch */
870 hash = hugetlb_fault_mutex_hash(mapping, index);
871 mutex_lock(&hugetlb_fault_mutex_table[hash]);
872
873 /* See if already present in mapping to avoid alloc/free */
874 folio = filemap_get_folio(mapping, index << huge_page_order(h));
875 if (!IS_ERR(folio)) {
876 folio_put(folio);
877 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
878 continue;
879 }
880
881 /*
882 * Allocate folio without setting the avoid_reserve argument.
883 * There certainly are no reserves associated with the
884 * pseudo_vma. However, there could be shared mappings with
885 * reserves for the file at the inode level. If we fallocate
886 * folios in these areas, we need to consume the reserves
887 * to keep reservation accounting consistent.
888 */
889 folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0);
890 if (IS_ERR(folio)) {
891 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
892 error = PTR_ERR(folio);
893 goto out;
894 }
895 clear_huge_page(&folio->page, addr, pages_per_huge_page(h));
896 __folio_mark_uptodate(folio);
897 error = hugetlb_add_to_page_cache(folio, mapping, index);
898 if (unlikely(error)) {
899 restore_reserve_on_error(h, &pseudo_vma, addr, folio);
900 folio_put(folio);
901 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
902 goto out;
903 }
904
905 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
906
907 folio_set_hugetlb_migratable(folio);
908 /*
909 * folio_unlock because locked by hugetlb_add_to_page_cache()
910 * folio_put() due to reference from alloc_hugetlb_folio()
911 */
912 folio_unlock(folio);
913 folio_put(folio);
914 }
915
916 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
917 i_size_write(inode, offset + len);
918 inode_set_ctime_current(inode);
919 out:
920 inode_unlock(inode);
921 return error;
922 }
923
hugetlbfs_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * attr)924 static int hugetlbfs_setattr(struct mnt_idmap *idmap,
925 struct dentry *dentry, struct iattr *attr)
926 {
927 struct inode *inode = d_inode(dentry);
928 struct hstate *h = hstate_inode(inode);
929 int error;
930 unsigned int ia_valid = attr->ia_valid;
931 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
932
933 error = setattr_prepare(idmap, dentry, attr);
934 if (error)
935 return error;
936
937 if (ia_valid & ATTR_SIZE) {
938 loff_t oldsize = inode->i_size;
939 loff_t newsize = attr->ia_size;
940
941 if (newsize & ~huge_page_mask(h))
942 return -EINVAL;
943 /* protected by i_rwsem */
944 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
945 (newsize > oldsize && (info->seals & F_SEAL_GROW)))
946 return -EPERM;
947 hugetlb_vmtruncate(inode, newsize);
948 }
949
950 setattr_copy(idmap, inode, attr);
951 mark_inode_dirty(inode);
952 return 0;
953 }
954
hugetlbfs_get_root(struct super_block * sb,struct hugetlbfs_fs_context * ctx)955 static struct inode *hugetlbfs_get_root(struct super_block *sb,
956 struct hugetlbfs_fs_context *ctx)
957 {
958 struct inode *inode;
959
960 inode = new_inode(sb);
961 if (inode) {
962 inode->i_ino = get_next_ino();
963 inode->i_mode = S_IFDIR | ctx->mode;
964 inode->i_uid = ctx->uid;
965 inode->i_gid = ctx->gid;
966 simple_inode_init_ts(inode);
967 inode->i_op = &hugetlbfs_dir_inode_operations;
968 inode->i_fop = &simple_dir_operations;
969 /* directory inodes start off with i_nlink == 2 (for "." entry) */
970 inc_nlink(inode);
971 lockdep_annotate_inode_mutex_key(inode);
972 }
973 return inode;
974 }
975
976 /*
977 * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
978 * be taken from reclaim -- unlike regular filesystems. This needs an
979 * annotation because huge_pmd_share() does an allocation under hugetlb's
980 * i_mmap_rwsem.
981 */
982 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
983
hugetlbfs_get_inode(struct super_block * sb,struct mnt_idmap * idmap,struct inode * dir,umode_t mode,dev_t dev)984 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
985 struct mnt_idmap *idmap,
986 struct inode *dir,
987 umode_t mode, dev_t dev)
988 {
989 struct inode *inode;
990 struct resv_map *resv_map = NULL;
991
992 /*
993 * Reserve maps are only needed for inodes that can have associated
994 * page allocations.
995 */
996 if (S_ISREG(mode) || S_ISLNK(mode)) {
997 resv_map = resv_map_alloc();
998 if (!resv_map)
999 return NULL;
1000 }
1001
1002 inode = new_inode(sb);
1003 if (inode) {
1004 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
1005
1006 inode->i_ino = get_next_ino();
1007 inode_init_owner(idmap, inode, dir, mode);
1008 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
1009 &hugetlbfs_i_mmap_rwsem_key);
1010 inode->i_mapping->a_ops = &hugetlbfs_aops;
1011 simple_inode_init_ts(inode);
1012 inode->i_mapping->i_private_data = resv_map;
1013 info->seals = F_SEAL_SEAL;
1014 switch (mode & S_IFMT) {
1015 default:
1016 init_special_inode(inode, mode, dev);
1017 break;
1018 case S_IFREG:
1019 inode->i_op = &hugetlbfs_inode_operations;
1020 inode->i_fop = &hugetlbfs_file_operations;
1021 break;
1022 case S_IFDIR:
1023 inode->i_op = &hugetlbfs_dir_inode_operations;
1024 inode->i_fop = &simple_dir_operations;
1025
1026 /* directory inodes start off with i_nlink == 2 (for "." entry) */
1027 inc_nlink(inode);
1028 break;
1029 case S_IFLNK:
1030 inode->i_op = &page_symlink_inode_operations;
1031 inode_nohighmem(inode);
1032 break;
1033 }
1034 lockdep_annotate_inode_mutex_key(inode);
1035 } else {
1036 if (resv_map)
1037 kref_put(&resv_map->refs, resv_map_release);
1038 }
1039
1040 return inode;
1041 }
1042
1043 /*
1044 * File creation. Allocate an inode, and we're done..
1045 */
hugetlbfs_mknod(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t dev)1046 static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1047 struct dentry *dentry, umode_t mode, dev_t dev)
1048 {
1049 struct inode *inode;
1050
1051 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, dev);
1052 if (!inode)
1053 return -ENOSPC;
1054 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1055 d_instantiate(dentry, inode);
1056 dget(dentry);/* Extra count - pin the dentry in core */
1057 return 0;
1058 }
1059
hugetlbfs_mkdir(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode)1060 static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
1061 struct dentry *dentry, umode_t mode)
1062 {
1063 int retval = hugetlbfs_mknod(idmap, dir, dentry,
1064 mode | S_IFDIR, 0);
1065 if (!retval)
1066 inc_nlink(dir);
1067 return retval;
1068 }
1069
hugetlbfs_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)1070 static int hugetlbfs_create(struct mnt_idmap *idmap,
1071 struct inode *dir, struct dentry *dentry,
1072 umode_t mode, bool excl)
1073 {
1074 return hugetlbfs_mknod(idmap, dir, dentry, mode | S_IFREG, 0);
1075 }
1076
hugetlbfs_tmpfile(struct mnt_idmap * idmap,struct inode * dir,struct file * file,umode_t mode)1077 static int hugetlbfs_tmpfile(struct mnt_idmap *idmap,
1078 struct inode *dir, struct file *file,
1079 umode_t mode)
1080 {
1081 struct inode *inode;
1082
1083 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode | S_IFREG, 0);
1084 if (!inode)
1085 return -ENOSPC;
1086 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1087 d_tmpfile(file, inode);
1088 return finish_open_simple(file, 0);
1089 }
1090
hugetlbfs_symlink(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,const char * symname)1091 static int hugetlbfs_symlink(struct mnt_idmap *idmap,
1092 struct inode *dir, struct dentry *dentry,
1093 const char *symname)
1094 {
1095 const umode_t mode = S_IFLNK|S_IRWXUGO;
1096 struct inode *inode;
1097 int error = -ENOSPC;
1098
1099 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, 0);
1100 if (inode) {
1101 int l = strlen(symname)+1;
1102 error = page_symlink(inode, symname, l);
1103 if (!error) {
1104 d_instantiate(dentry, inode);
1105 dget(dentry);
1106 } else
1107 iput(inode);
1108 }
1109 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1110
1111 return error;
1112 }
1113
1114 #ifdef CONFIG_MIGRATION
hugetlbfs_migrate_folio(struct address_space * mapping,struct folio * dst,struct folio * src,enum migrate_mode mode)1115 static int hugetlbfs_migrate_folio(struct address_space *mapping,
1116 struct folio *dst, struct folio *src,
1117 enum migrate_mode mode)
1118 {
1119 int rc;
1120
1121 rc = migrate_huge_page_move_mapping(mapping, dst, src);
1122 if (rc != MIGRATEPAGE_SUCCESS)
1123 return rc;
1124
1125 if (hugetlb_folio_subpool(src)) {
1126 hugetlb_set_folio_subpool(dst,
1127 hugetlb_folio_subpool(src));
1128 hugetlb_set_folio_subpool(src, NULL);
1129 }
1130
1131 if (mode != MIGRATE_SYNC_NO_COPY)
1132 folio_migrate_copy(dst, src);
1133 else
1134 folio_migrate_flags(dst, src);
1135
1136 return MIGRATEPAGE_SUCCESS;
1137 }
1138 #else
1139 #define hugetlbfs_migrate_folio NULL
1140 #endif
1141
hugetlbfs_error_remove_folio(struct address_space * mapping,struct folio * folio)1142 static int hugetlbfs_error_remove_folio(struct address_space *mapping,
1143 struct folio *folio)
1144 {
1145 return 0;
1146 }
1147
1148 /*
1149 * Display the mount options in /proc/mounts.
1150 */
hugetlbfs_show_options(struct seq_file * m,struct dentry * root)1151 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1152 {
1153 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1154 struct hugepage_subpool *spool = sbinfo->spool;
1155 unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1156 unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1157 char mod;
1158
1159 if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1160 seq_printf(m, ",uid=%u",
1161 from_kuid_munged(&init_user_ns, sbinfo->uid));
1162 if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1163 seq_printf(m, ",gid=%u",
1164 from_kgid_munged(&init_user_ns, sbinfo->gid));
1165 if (sbinfo->mode != 0755)
1166 seq_printf(m, ",mode=%o", sbinfo->mode);
1167 if (sbinfo->max_inodes != -1)
1168 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1169
1170 hpage_size /= 1024;
1171 mod = 'K';
1172 if (hpage_size >= 1024) {
1173 hpage_size /= 1024;
1174 mod = 'M';
1175 }
1176 seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1177 if (spool) {
1178 if (spool->max_hpages != -1)
1179 seq_printf(m, ",size=%llu",
1180 (unsigned long long)spool->max_hpages << hpage_shift);
1181 if (spool->min_hpages != -1)
1182 seq_printf(m, ",min_size=%llu",
1183 (unsigned long long)spool->min_hpages << hpage_shift);
1184 }
1185 return 0;
1186 }
1187
hugetlbfs_statfs(struct dentry * dentry,struct kstatfs * buf)1188 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1189 {
1190 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1191 struct hstate *h = hstate_inode(d_inode(dentry));
1192 u64 id = huge_encode_dev(dentry->d_sb->s_dev);
1193
1194 buf->f_fsid = u64_to_fsid(id);
1195 buf->f_type = HUGETLBFS_MAGIC;
1196 buf->f_bsize = huge_page_size(h);
1197 if (sbinfo) {
1198 spin_lock(&sbinfo->stat_lock);
1199 /* If no limits set, just report 0 or -1 for max/free/used
1200 * blocks, like simple_statfs() */
1201 if (sbinfo->spool) {
1202 long free_pages;
1203
1204 spin_lock_irq(&sbinfo->spool->lock);
1205 buf->f_blocks = sbinfo->spool->max_hpages;
1206 free_pages = sbinfo->spool->max_hpages
1207 - sbinfo->spool->used_hpages;
1208 buf->f_bavail = buf->f_bfree = free_pages;
1209 spin_unlock_irq(&sbinfo->spool->lock);
1210 buf->f_files = sbinfo->max_inodes;
1211 buf->f_ffree = sbinfo->free_inodes;
1212 }
1213 spin_unlock(&sbinfo->stat_lock);
1214 }
1215 buf->f_namelen = NAME_MAX;
1216 return 0;
1217 }
1218
hugetlbfs_put_super(struct super_block * sb)1219 static void hugetlbfs_put_super(struct super_block *sb)
1220 {
1221 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1222
1223 if (sbi) {
1224 sb->s_fs_info = NULL;
1225
1226 if (sbi->spool)
1227 hugepage_put_subpool(sbi->spool);
1228
1229 kfree(sbi);
1230 }
1231 }
1232
hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info * sbinfo)1233 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1234 {
1235 if (sbinfo->free_inodes >= 0) {
1236 spin_lock(&sbinfo->stat_lock);
1237 if (unlikely(!sbinfo->free_inodes)) {
1238 spin_unlock(&sbinfo->stat_lock);
1239 return 0;
1240 }
1241 sbinfo->free_inodes--;
1242 spin_unlock(&sbinfo->stat_lock);
1243 }
1244
1245 return 1;
1246 }
1247
hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info * sbinfo)1248 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1249 {
1250 if (sbinfo->free_inodes >= 0) {
1251 spin_lock(&sbinfo->stat_lock);
1252 sbinfo->free_inodes++;
1253 spin_unlock(&sbinfo->stat_lock);
1254 }
1255 }
1256
1257
1258 static struct kmem_cache *hugetlbfs_inode_cachep;
1259
hugetlbfs_alloc_inode(struct super_block * sb)1260 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1261 {
1262 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1263 struct hugetlbfs_inode_info *p;
1264
1265 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1266 return NULL;
1267 p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
1268 if (unlikely(!p)) {
1269 hugetlbfs_inc_free_inodes(sbinfo);
1270 return NULL;
1271 }
1272 return &p->vfs_inode;
1273 }
1274
hugetlbfs_free_inode(struct inode * inode)1275 static void hugetlbfs_free_inode(struct inode *inode)
1276 {
1277 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1278 }
1279
hugetlbfs_destroy_inode(struct inode * inode)1280 static void hugetlbfs_destroy_inode(struct inode *inode)
1281 {
1282 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1283 }
1284
1285 static const struct address_space_operations hugetlbfs_aops = {
1286 .write_begin = hugetlbfs_write_begin,
1287 .write_end = hugetlbfs_write_end,
1288 .dirty_folio = noop_dirty_folio,
1289 .migrate_folio = hugetlbfs_migrate_folio,
1290 .error_remove_folio = hugetlbfs_error_remove_folio,
1291 };
1292
1293
init_once(void * foo)1294 static void init_once(void *foo)
1295 {
1296 struct hugetlbfs_inode_info *ei = foo;
1297
1298 inode_init_once(&ei->vfs_inode);
1299 }
1300
1301 static const struct file_operations hugetlbfs_file_operations = {
1302 .read_iter = hugetlbfs_read_iter,
1303 .mmap = hugetlbfs_file_mmap,
1304 .fsync = noop_fsync,
1305 .get_unmapped_area = hugetlb_get_unmapped_area,
1306 .llseek = default_llseek,
1307 .fallocate = hugetlbfs_fallocate,
1308 .fop_flags = FOP_HUGE_PAGES,
1309 };
1310
1311 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1312 .create = hugetlbfs_create,
1313 .lookup = simple_lookup,
1314 .link = simple_link,
1315 .unlink = simple_unlink,
1316 .symlink = hugetlbfs_symlink,
1317 .mkdir = hugetlbfs_mkdir,
1318 .rmdir = simple_rmdir,
1319 .mknod = hugetlbfs_mknod,
1320 .rename = simple_rename,
1321 .setattr = hugetlbfs_setattr,
1322 .tmpfile = hugetlbfs_tmpfile,
1323 };
1324
1325 static const struct inode_operations hugetlbfs_inode_operations = {
1326 .setattr = hugetlbfs_setattr,
1327 };
1328
1329 static const struct super_operations hugetlbfs_ops = {
1330 .alloc_inode = hugetlbfs_alloc_inode,
1331 .free_inode = hugetlbfs_free_inode,
1332 .destroy_inode = hugetlbfs_destroy_inode,
1333 .evict_inode = hugetlbfs_evict_inode,
1334 .statfs = hugetlbfs_statfs,
1335 .put_super = hugetlbfs_put_super,
1336 .show_options = hugetlbfs_show_options,
1337 };
1338
1339 /*
1340 * Convert size option passed from command line to number of huge pages
1341 * in the pool specified by hstate. Size option could be in bytes
1342 * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1343 */
1344 static long
hugetlbfs_size_to_hpages(struct hstate * h,unsigned long long size_opt,enum hugetlbfs_size_type val_type)1345 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1346 enum hugetlbfs_size_type val_type)
1347 {
1348 if (val_type == NO_SIZE)
1349 return -1;
1350
1351 if (val_type == SIZE_PERCENT) {
1352 size_opt <<= huge_page_shift(h);
1353 size_opt *= h->max_huge_pages;
1354 do_div(size_opt, 100);
1355 }
1356
1357 size_opt >>= huge_page_shift(h);
1358 return size_opt;
1359 }
1360
1361 /*
1362 * Parse one mount parameter.
1363 */
hugetlbfs_parse_param(struct fs_context * fc,struct fs_parameter * param)1364 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1365 {
1366 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1367 struct fs_parse_result result;
1368 struct hstate *h;
1369 char *rest;
1370 unsigned long ps;
1371 int opt;
1372
1373 opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1374 if (opt < 0)
1375 return opt;
1376
1377 switch (opt) {
1378 case Opt_uid:
1379 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1380 if (!uid_valid(ctx->uid))
1381 goto bad_val;
1382 return 0;
1383
1384 case Opt_gid:
1385 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1386 if (!gid_valid(ctx->gid))
1387 goto bad_val;
1388 return 0;
1389
1390 case Opt_mode:
1391 ctx->mode = result.uint_32 & 01777U;
1392 return 0;
1393
1394 case Opt_size:
1395 /* memparse() will accept a K/M/G without a digit */
1396 if (!param->string || !isdigit(param->string[0]))
1397 goto bad_val;
1398 ctx->max_size_opt = memparse(param->string, &rest);
1399 ctx->max_val_type = SIZE_STD;
1400 if (*rest == '%')
1401 ctx->max_val_type = SIZE_PERCENT;
1402 return 0;
1403
1404 case Opt_nr_inodes:
1405 /* memparse() will accept a K/M/G without a digit */
1406 if (!param->string || !isdigit(param->string[0]))
1407 goto bad_val;
1408 ctx->nr_inodes = memparse(param->string, &rest);
1409 return 0;
1410
1411 case Opt_pagesize:
1412 ps = memparse(param->string, &rest);
1413 h = size_to_hstate(ps);
1414 if (!h) {
1415 pr_err("Unsupported page size %lu MB\n", ps / SZ_1M);
1416 return -EINVAL;
1417 }
1418 ctx->hstate = h;
1419 return 0;
1420
1421 case Opt_min_size:
1422 /* memparse() will accept a K/M/G without a digit */
1423 if (!param->string || !isdigit(param->string[0]))
1424 goto bad_val;
1425 ctx->min_size_opt = memparse(param->string, &rest);
1426 ctx->min_val_type = SIZE_STD;
1427 if (*rest == '%')
1428 ctx->min_val_type = SIZE_PERCENT;
1429 return 0;
1430
1431 default:
1432 return -EINVAL;
1433 }
1434
1435 bad_val:
1436 return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1437 param->string, param->key);
1438 }
1439
1440 /*
1441 * Validate the parsed options.
1442 */
hugetlbfs_validate(struct fs_context * fc)1443 static int hugetlbfs_validate(struct fs_context *fc)
1444 {
1445 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1446
1447 /*
1448 * Use huge page pool size (in hstate) to convert the size
1449 * options to number of huge pages. If NO_SIZE, -1 is returned.
1450 */
1451 ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1452 ctx->max_size_opt,
1453 ctx->max_val_type);
1454 ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1455 ctx->min_size_opt,
1456 ctx->min_val_type);
1457
1458 /*
1459 * If max_size was specified, then min_size must be smaller
1460 */
1461 if (ctx->max_val_type > NO_SIZE &&
1462 ctx->min_hpages > ctx->max_hpages) {
1463 pr_err("Minimum size can not be greater than maximum size\n");
1464 return -EINVAL;
1465 }
1466
1467 return 0;
1468 }
1469
1470 static int
hugetlbfs_fill_super(struct super_block * sb,struct fs_context * fc)1471 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1472 {
1473 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1474 struct hugetlbfs_sb_info *sbinfo;
1475
1476 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1477 if (!sbinfo)
1478 return -ENOMEM;
1479 sb->s_fs_info = sbinfo;
1480 spin_lock_init(&sbinfo->stat_lock);
1481 sbinfo->hstate = ctx->hstate;
1482 sbinfo->max_inodes = ctx->nr_inodes;
1483 sbinfo->free_inodes = ctx->nr_inodes;
1484 sbinfo->spool = NULL;
1485 sbinfo->uid = ctx->uid;
1486 sbinfo->gid = ctx->gid;
1487 sbinfo->mode = ctx->mode;
1488
1489 /*
1490 * Allocate and initialize subpool if maximum or minimum size is
1491 * specified. Any needed reservations (for minimum size) are taken
1492 * when the subpool is created.
1493 */
1494 if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1495 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1496 ctx->max_hpages,
1497 ctx->min_hpages);
1498 if (!sbinfo->spool)
1499 goto out_free;
1500 }
1501 sb->s_maxbytes = MAX_LFS_FILESIZE;
1502 sb->s_blocksize = huge_page_size(ctx->hstate);
1503 sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1504 sb->s_magic = HUGETLBFS_MAGIC;
1505 sb->s_op = &hugetlbfs_ops;
1506 sb->s_time_gran = 1;
1507
1508 /*
1509 * Due to the special and limited functionality of hugetlbfs, it does
1510 * not work well as a stacking filesystem.
1511 */
1512 sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1513 sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1514 if (!sb->s_root)
1515 goto out_free;
1516 return 0;
1517 out_free:
1518 kfree(sbinfo->spool);
1519 kfree(sbinfo);
1520 return -ENOMEM;
1521 }
1522
hugetlbfs_get_tree(struct fs_context * fc)1523 static int hugetlbfs_get_tree(struct fs_context *fc)
1524 {
1525 int err = hugetlbfs_validate(fc);
1526 if (err)
1527 return err;
1528 return get_tree_nodev(fc, hugetlbfs_fill_super);
1529 }
1530
hugetlbfs_fs_context_free(struct fs_context * fc)1531 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1532 {
1533 kfree(fc->fs_private);
1534 }
1535
1536 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1537 .free = hugetlbfs_fs_context_free,
1538 .parse_param = hugetlbfs_parse_param,
1539 .get_tree = hugetlbfs_get_tree,
1540 };
1541
hugetlbfs_init_fs_context(struct fs_context * fc)1542 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1543 {
1544 struct hugetlbfs_fs_context *ctx;
1545
1546 ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1547 if (!ctx)
1548 return -ENOMEM;
1549
1550 ctx->max_hpages = -1; /* No limit on size by default */
1551 ctx->nr_inodes = -1; /* No limit on number of inodes by default */
1552 ctx->uid = current_fsuid();
1553 ctx->gid = current_fsgid();
1554 ctx->mode = 0755;
1555 ctx->hstate = &default_hstate;
1556 ctx->min_hpages = -1; /* No default minimum size */
1557 ctx->max_val_type = NO_SIZE;
1558 ctx->min_val_type = NO_SIZE;
1559 fc->fs_private = ctx;
1560 fc->ops = &hugetlbfs_fs_context_ops;
1561 return 0;
1562 }
1563
1564 static struct file_system_type hugetlbfs_fs_type = {
1565 .name = "hugetlbfs",
1566 .init_fs_context = hugetlbfs_init_fs_context,
1567 .parameters = hugetlb_fs_parameters,
1568 .kill_sb = kill_litter_super,
1569 .fs_flags = FS_ALLOW_IDMAP,
1570 };
1571
1572 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1573
can_do_hugetlb_shm(void)1574 static int can_do_hugetlb_shm(void)
1575 {
1576 kgid_t shm_group;
1577 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1578 return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1579 }
1580
get_hstate_idx(int page_size_log)1581 static int get_hstate_idx(int page_size_log)
1582 {
1583 struct hstate *h = hstate_sizelog(page_size_log);
1584
1585 if (!h)
1586 return -1;
1587 return hstate_index(h);
1588 }
1589
1590 /*
1591 * Note that size should be aligned to proper hugepage size in caller side,
1592 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1593 */
hugetlb_file_setup(const char * name,size_t size,vm_flags_t acctflag,int creat_flags,int page_size_log)1594 struct file *hugetlb_file_setup(const char *name, size_t size,
1595 vm_flags_t acctflag, int creat_flags,
1596 int page_size_log)
1597 {
1598 struct inode *inode;
1599 struct vfsmount *mnt;
1600 int hstate_idx;
1601 struct file *file;
1602
1603 hstate_idx = get_hstate_idx(page_size_log);
1604 if (hstate_idx < 0)
1605 return ERR_PTR(-ENODEV);
1606
1607 mnt = hugetlbfs_vfsmount[hstate_idx];
1608 if (!mnt)
1609 return ERR_PTR(-ENOENT);
1610
1611 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1612 struct ucounts *ucounts = current_ucounts();
1613
1614 if (user_shm_lock(size, ucounts)) {
1615 pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
1616 current->comm, current->pid);
1617 user_shm_unlock(size, ucounts);
1618 }
1619 return ERR_PTR(-EPERM);
1620 }
1621
1622 file = ERR_PTR(-ENOSPC);
1623 /* hugetlbfs_vfsmount[] mounts do not use idmapped mounts. */
1624 inode = hugetlbfs_get_inode(mnt->mnt_sb, &nop_mnt_idmap, NULL,
1625 S_IFREG | S_IRWXUGO, 0);
1626 if (!inode)
1627 goto out;
1628 if (creat_flags == HUGETLB_SHMFS_INODE)
1629 inode->i_flags |= S_PRIVATE;
1630
1631 inode->i_size = size;
1632 clear_nlink(inode);
1633
1634 if (!hugetlb_reserve_pages(inode, 0,
1635 size >> huge_page_shift(hstate_inode(inode)), NULL,
1636 acctflag))
1637 file = ERR_PTR(-ENOMEM);
1638 else
1639 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1640 &hugetlbfs_file_operations);
1641 if (!IS_ERR(file))
1642 return file;
1643
1644 iput(inode);
1645 out:
1646 return file;
1647 }
1648
mount_one_hugetlbfs(struct hstate * h)1649 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1650 {
1651 struct fs_context *fc;
1652 struct vfsmount *mnt;
1653
1654 fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1655 if (IS_ERR(fc)) {
1656 mnt = ERR_CAST(fc);
1657 } else {
1658 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1659 ctx->hstate = h;
1660 mnt = fc_mount(fc);
1661 put_fs_context(fc);
1662 }
1663 if (IS_ERR(mnt))
1664 pr_err("Cannot mount internal hugetlbfs for page size %luK",
1665 huge_page_size(h) / SZ_1K);
1666 return mnt;
1667 }
1668
init_hugetlbfs_fs(void)1669 static int __init init_hugetlbfs_fs(void)
1670 {
1671 struct vfsmount *mnt;
1672 struct hstate *h;
1673 int error;
1674 int i;
1675
1676 if (!hugepages_supported()) {
1677 pr_info("disabling because there are no supported hugepage sizes\n");
1678 return -ENOTSUPP;
1679 }
1680
1681 error = -ENOMEM;
1682 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1683 sizeof(struct hugetlbfs_inode_info),
1684 0, SLAB_ACCOUNT, init_once);
1685 if (hugetlbfs_inode_cachep == NULL)
1686 goto out;
1687
1688 error = register_filesystem(&hugetlbfs_fs_type);
1689 if (error)
1690 goto out_free;
1691
1692 /* default hstate mount is required */
1693 mnt = mount_one_hugetlbfs(&default_hstate);
1694 if (IS_ERR(mnt)) {
1695 error = PTR_ERR(mnt);
1696 goto out_unreg;
1697 }
1698 hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1699
1700 /* other hstates are optional */
1701 i = 0;
1702 for_each_hstate(h) {
1703 if (i == default_hstate_idx) {
1704 i++;
1705 continue;
1706 }
1707
1708 mnt = mount_one_hugetlbfs(h);
1709 if (IS_ERR(mnt))
1710 hugetlbfs_vfsmount[i] = NULL;
1711 else
1712 hugetlbfs_vfsmount[i] = mnt;
1713 i++;
1714 }
1715
1716 return 0;
1717
1718 out_unreg:
1719 (void)unregister_filesystem(&hugetlbfs_fs_type);
1720 out_free:
1721 kmem_cache_destroy(hugetlbfs_inode_cachep);
1722 out:
1723 return error;
1724 }
1725 fs_initcall(init_hugetlbfs_fs)
1726