xref: /linux/fs/hugetlbfs/inode.c (revision 2c1ed907520c50326b8f604907a8478b27881a2e)
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 #define CREATE_TRACE_POINTS
43 #include <trace/events/hugetlbfs.h>
44 
45 static const struct address_space_operations hugetlbfs_aops;
46 static const struct file_operations hugetlbfs_file_operations;
47 static const struct inode_operations hugetlbfs_dir_inode_operations;
48 static const struct inode_operations hugetlbfs_inode_operations;
49 
50 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
51 
52 struct hugetlbfs_fs_context {
53 	struct hstate		*hstate;
54 	unsigned long long	max_size_opt;
55 	unsigned long long	min_size_opt;
56 	long			max_hpages;
57 	long			nr_inodes;
58 	long			min_hpages;
59 	enum hugetlbfs_size_type max_val_type;
60 	enum hugetlbfs_size_type min_val_type;
61 	kuid_t			uid;
62 	kgid_t			gid;
63 	umode_t			mode;
64 };
65 
66 int sysctl_hugetlb_shm_group;
67 
68 enum hugetlb_param {
69 	Opt_gid,
70 	Opt_min_size,
71 	Opt_mode,
72 	Opt_nr_inodes,
73 	Opt_pagesize,
74 	Opt_size,
75 	Opt_uid,
76 };
77 
78 static const struct fs_parameter_spec hugetlb_fs_parameters[] = {
79 	fsparam_gid   ("gid",		Opt_gid),
80 	fsparam_string("min_size",	Opt_min_size),
81 	fsparam_u32oct("mode",		Opt_mode),
82 	fsparam_string("nr_inodes",	Opt_nr_inodes),
83 	fsparam_string("pagesize",	Opt_pagesize),
84 	fsparam_string("size",		Opt_size),
85 	fsparam_uid   ("uid",		Opt_uid),
86 	{}
87 };
88 
89 /*
90  * Mask used when checking the page offset value passed in via system
91  * calls.  This value will be converted to a loff_t which is signed.
92  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
93  * value.  The extra bit (- 1 in the shift value) is to take the sign
94  * bit into account.
95  */
96 #define PGOFF_LOFFT_MAX \
97 	(((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
98 
hugetlbfs_file_mmap(struct file * file,struct vm_area_struct * vma)99 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
100 {
101 	struct inode *inode = file_inode(file);
102 	loff_t len, vma_len;
103 	int ret;
104 	struct hstate *h = hstate_file(file);
105 	vm_flags_t vm_flags;
106 
107 	/*
108 	 * vma address alignment (but not the pgoff alignment) has
109 	 * already been checked by prepare_hugepage_range.  If you add
110 	 * any error returns here, do so after setting VM_HUGETLB, so
111 	 * is_vm_hugetlb_page tests below unmap_region go the right
112 	 * way when do_mmap unwinds (may be important on powerpc
113 	 * and ia64).
114 	 */
115 	vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND);
116 	vma->vm_ops = &hugetlb_vm_ops;
117 
118 	/*
119 	 * page based offset in vm_pgoff could be sufficiently large to
120 	 * overflow a loff_t when converted to byte offset.  This can
121 	 * only happen on architectures where sizeof(loff_t) ==
122 	 * sizeof(unsigned long).  So, only check in those instances.
123 	 */
124 	if (sizeof(unsigned long) == sizeof(loff_t)) {
125 		if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
126 			return -EINVAL;
127 	}
128 
129 	/* must be huge page aligned */
130 	if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
131 		return -EINVAL;
132 
133 	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
134 	len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
135 	/* check for overflow */
136 	if (len < vma_len)
137 		return -EINVAL;
138 
139 	inode_lock(inode);
140 	file_accessed(file);
141 
142 	ret = -ENOMEM;
143 
144 	vm_flags = vma->vm_flags;
145 	/*
146 	 * for SHM_HUGETLB, the pages are reserved in the shmget() call so skip
147 	 * reserving here. Note: only for SHM hugetlbfs file, the inode
148 	 * flag S_PRIVATE is set.
149 	 */
150 	if (inode->i_flags & S_PRIVATE)
151 		vm_flags |= VM_NORESERVE;
152 
153 	if (!hugetlb_reserve_pages(inode,
154 				vma->vm_pgoff >> huge_page_order(h),
155 				len >> huge_page_shift(h), vma,
156 				vm_flags))
157 		goto out;
158 
159 	ret = 0;
160 	if (vma->vm_flags & VM_WRITE && inode->i_size < len)
161 		i_size_write(inode, len);
162 out:
163 	inode_unlock(inode);
164 
165 	return ret;
166 }
167 
168 /*
169  * Called under mmap_write_lock(mm).
170  */
171 
172 unsigned long
hugetlb_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)173 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
174 			    unsigned long len, unsigned long pgoff,
175 			    unsigned long flags)
176 {
177 	unsigned long addr0 = 0;
178 	struct hstate *h = hstate_file(file);
179 
180 	if (len & ~huge_page_mask(h))
181 		return -EINVAL;
182 	if (flags & MAP_FIXED) {
183 		if (addr & ~huge_page_mask(h))
184 			return -EINVAL;
185 		if (prepare_hugepage_range(file, addr, len))
186 			return -EINVAL;
187 	}
188 	if (addr)
189 		addr0 = ALIGN(addr, huge_page_size(h));
190 
191 	return mm_get_unmapped_area_vmflags(current->mm, file, addr0, len, pgoff,
192 					    flags, 0);
193 }
194 
195 /*
196  * Someone wants to read @bytes from a HWPOISON hugetlb @page from @offset.
197  * Returns the maximum number of bytes one can read without touching the 1st raw
198  * HWPOISON subpage.
199  *
200  * The implementation borrows the iteration logic from copy_page_to_iter*.
201  */
adjust_range_hwpoison(struct page * page,size_t offset,size_t bytes)202 static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t bytes)
203 {
204 	size_t n = 0;
205 	size_t res = 0;
206 
207 	/* First subpage to start the loop. */
208 	page = nth_page(page, offset / PAGE_SIZE);
209 	offset %= PAGE_SIZE;
210 	while (1) {
211 		if (is_raw_hwpoison_page_in_hugepage(page))
212 			break;
213 
214 		/* Safe to read n bytes without touching HWPOISON subpage. */
215 		n = min(bytes, (size_t)PAGE_SIZE - offset);
216 		res += n;
217 		bytes -= n;
218 		if (!bytes || !n)
219 			break;
220 		offset += n;
221 		if (offset == PAGE_SIZE) {
222 			page = nth_page(page, 1);
223 			offset = 0;
224 		}
225 	}
226 
227 	return res;
228 }
229 
230 /*
231  * Support for read() - Find the page attached to f_mapping and copy out the
232  * data. This provides functionality similar to filemap_read().
233  */
hugetlbfs_read_iter(struct kiocb * iocb,struct iov_iter * to)234 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
235 {
236 	struct file *file = iocb->ki_filp;
237 	struct hstate *h = hstate_file(file);
238 	struct address_space *mapping = file->f_mapping;
239 	struct inode *inode = mapping->host;
240 	unsigned long index = iocb->ki_pos >> huge_page_shift(h);
241 	unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
242 	unsigned long end_index;
243 	loff_t isize;
244 	ssize_t retval = 0;
245 
246 	while (iov_iter_count(to)) {
247 		struct folio *folio;
248 		size_t nr, copied, want;
249 
250 		/* nr is the maximum number of bytes to copy from this page */
251 		nr = huge_page_size(h);
252 		isize = i_size_read(inode);
253 		if (!isize)
254 			break;
255 		end_index = (isize - 1) >> huge_page_shift(h);
256 		if (index > end_index)
257 			break;
258 		if (index == end_index) {
259 			nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
260 			if (nr <= offset)
261 				break;
262 		}
263 		nr = nr - offset;
264 
265 		/* Find the folio */
266 		folio = filemap_lock_hugetlb_folio(h, mapping, index);
267 		if (IS_ERR(folio)) {
268 			/*
269 			 * We have a HOLE, zero out the user-buffer for the
270 			 * length of the hole or request.
271 			 */
272 			copied = iov_iter_zero(nr, to);
273 		} else {
274 			folio_unlock(folio);
275 
276 			if (!folio_test_hwpoison(folio))
277 				want = nr;
278 			else {
279 				/*
280 				 * Adjust how many bytes safe to read without
281 				 * touching the 1st raw HWPOISON subpage after
282 				 * offset.
283 				 */
284 				want = adjust_range_hwpoison(&folio->page, offset, nr);
285 				if (want == 0) {
286 					folio_put(folio);
287 					retval = -EIO;
288 					break;
289 				}
290 			}
291 
292 			/*
293 			 * We have the folio, copy it to user space buffer.
294 			 */
295 			copied = copy_folio_to_iter(folio, offset, want, to);
296 			folio_put(folio);
297 		}
298 		offset += copied;
299 		retval += copied;
300 		if (copied != nr && iov_iter_count(to)) {
301 			if (!retval)
302 				retval = -EFAULT;
303 			break;
304 		}
305 		index += offset >> huge_page_shift(h);
306 		offset &= ~huge_page_mask(h);
307 	}
308 	iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
309 	return retval;
310 }
311 
hugetlbfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)312 static int hugetlbfs_write_begin(struct file *file,
313 			struct address_space *mapping,
314 			loff_t pos, unsigned len,
315 			struct folio **foliop, void **fsdata)
316 {
317 	return -EINVAL;
318 }
319 
hugetlbfs_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)320 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
321 			loff_t pos, unsigned len, unsigned copied,
322 			struct folio *folio, void *fsdata)
323 {
324 	BUG();
325 	return -EINVAL;
326 }
327 
hugetlb_delete_from_page_cache(struct folio * folio)328 static void hugetlb_delete_from_page_cache(struct folio *folio)
329 {
330 	folio_clear_dirty(folio);
331 	folio_clear_uptodate(folio);
332 	filemap_remove_folio(folio);
333 }
334 
335 /*
336  * Called with i_mmap_rwsem held for inode based vma maps.  This makes
337  * sure vma (and vm_mm) will not go away.  We also hold the hugetlb fault
338  * mutex for the page in the mapping.  So, we can not race with page being
339  * faulted into the vma.
340  */
hugetlb_vma_maps_page(struct vm_area_struct * vma,unsigned long addr,struct page * page)341 static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
342 				unsigned long addr, struct page *page)
343 {
344 	pte_t *ptep, pte;
345 
346 	ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma)));
347 	if (!ptep)
348 		return false;
349 
350 	pte = huge_ptep_get(vma->vm_mm, addr, ptep);
351 	if (huge_pte_none(pte) || !pte_present(pte))
352 		return false;
353 
354 	if (pte_page(pte) == page)
355 		return true;
356 
357 	return false;
358 }
359 
360 /*
361  * Can vma_offset_start/vma_offset_end overflow on 32-bit arches?
362  * No, because the interval tree returns us only those vmas
363  * which overlap the truncated area starting at pgoff,
364  * and no vma on a 32-bit arch can span beyond the 4GB.
365  */
vma_offset_start(struct vm_area_struct * vma,pgoff_t start)366 static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start)
367 {
368 	unsigned long offset = 0;
369 
370 	if (vma->vm_pgoff < start)
371 		offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
372 
373 	return vma->vm_start + offset;
374 }
375 
vma_offset_end(struct vm_area_struct * vma,pgoff_t end)376 static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end)
377 {
378 	unsigned long t_end;
379 
380 	if (!end)
381 		return vma->vm_end;
382 
383 	t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start;
384 	if (t_end > vma->vm_end)
385 		t_end = vma->vm_end;
386 	return t_end;
387 }
388 
389 /*
390  * Called with hugetlb fault mutex held.  Therefore, no more mappings to
391  * this folio can be created while executing the routine.
392  */
hugetlb_unmap_file_folio(struct hstate * h,struct address_space * mapping,struct folio * folio,pgoff_t index)393 static void hugetlb_unmap_file_folio(struct hstate *h,
394 					struct address_space *mapping,
395 					struct folio *folio, pgoff_t index)
396 {
397 	struct rb_root_cached *root = &mapping->i_mmap;
398 	struct hugetlb_vma_lock *vma_lock;
399 	struct page *page = &folio->page;
400 	struct vm_area_struct *vma;
401 	unsigned long v_start;
402 	unsigned long v_end;
403 	pgoff_t start, end;
404 
405 	start = index * pages_per_huge_page(h);
406 	end = (index + 1) * pages_per_huge_page(h);
407 
408 	i_mmap_lock_write(mapping);
409 retry:
410 	vma_lock = NULL;
411 	vma_interval_tree_foreach(vma, root, start, end - 1) {
412 		v_start = vma_offset_start(vma, start);
413 		v_end = vma_offset_end(vma, end);
414 
415 		if (!hugetlb_vma_maps_page(vma, v_start, page))
416 			continue;
417 
418 		if (!hugetlb_vma_trylock_write(vma)) {
419 			vma_lock = vma->vm_private_data;
420 			/*
421 			 * If we can not get vma lock, we need to drop
422 			 * immap_sema and take locks in order.  First,
423 			 * take a ref on the vma_lock structure so that
424 			 * we can be guaranteed it will not go away when
425 			 * dropping immap_sema.
426 			 */
427 			kref_get(&vma_lock->refs);
428 			break;
429 		}
430 
431 		unmap_hugepage_range(vma, v_start, v_end, NULL,
432 				     ZAP_FLAG_DROP_MARKER);
433 		hugetlb_vma_unlock_write(vma);
434 	}
435 
436 	i_mmap_unlock_write(mapping);
437 
438 	if (vma_lock) {
439 		/*
440 		 * Wait on vma_lock.  We know it is still valid as we have
441 		 * a reference.  We must 'open code' vma locking as we do
442 		 * not know if vma_lock is still attached to vma.
443 		 */
444 		down_write(&vma_lock->rw_sema);
445 		i_mmap_lock_write(mapping);
446 
447 		vma = vma_lock->vma;
448 		if (!vma) {
449 			/*
450 			 * If lock is no longer attached to vma, then just
451 			 * unlock, drop our reference and retry looking for
452 			 * other vmas.
453 			 */
454 			up_write(&vma_lock->rw_sema);
455 			kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
456 			goto retry;
457 		}
458 
459 		/*
460 		 * vma_lock is still attached to vma.  Check to see if vma
461 		 * still maps page and if so, unmap.
462 		 */
463 		v_start = vma_offset_start(vma, start);
464 		v_end = vma_offset_end(vma, end);
465 		if (hugetlb_vma_maps_page(vma, v_start, page))
466 			unmap_hugepage_range(vma, v_start, v_end, NULL,
467 					     ZAP_FLAG_DROP_MARKER);
468 
469 		kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
470 		hugetlb_vma_unlock_write(vma);
471 
472 		goto retry;
473 	}
474 }
475 
476 static void
hugetlb_vmdelete_list(struct rb_root_cached * root,pgoff_t start,pgoff_t end,zap_flags_t zap_flags)477 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
478 		      zap_flags_t zap_flags)
479 {
480 	struct vm_area_struct *vma;
481 
482 	/*
483 	 * end == 0 indicates that the entire range after start should be
484 	 * unmapped.  Note, end is exclusive, whereas the interval tree takes
485 	 * an inclusive "last".
486 	 */
487 	vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
488 		unsigned long v_start;
489 		unsigned long v_end;
490 
491 		if (!hugetlb_vma_trylock_write(vma))
492 			continue;
493 
494 		v_start = vma_offset_start(vma, start);
495 		v_end = vma_offset_end(vma, end);
496 
497 		unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags);
498 
499 		/*
500 		 * Note that vma lock only exists for shared/non-private
501 		 * vmas.  Therefore, lock is not held when calling
502 		 * unmap_hugepage_range for private vmas.
503 		 */
504 		hugetlb_vma_unlock_write(vma);
505 	}
506 }
507 
508 /*
509  * Called with hugetlb fault mutex held.
510  * Returns true if page was actually removed, false otherwise.
511  */
remove_inode_single_folio(struct hstate * h,struct inode * inode,struct address_space * mapping,struct folio * folio,pgoff_t index,bool truncate_op)512 static bool remove_inode_single_folio(struct hstate *h, struct inode *inode,
513 					struct address_space *mapping,
514 					struct folio *folio, pgoff_t index,
515 					bool truncate_op)
516 {
517 	bool ret = false;
518 
519 	/*
520 	 * If folio is mapped, it was faulted in after being
521 	 * unmapped in caller.  Unmap (again) while holding
522 	 * the fault mutex.  The mutex will prevent faults
523 	 * until we finish removing the folio.
524 	 */
525 	if (unlikely(folio_mapped(folio)))
526 		hugetlb_unmap_file_folio(h, mapping, folio, index);
527 
528 	folio_lock(folio);
529 	/*
530 	 * We must remove the folio from page cache before removing
531 	 * the region/ reserve map (hugetlb_unreserve_pages).  In
532 	 * rare out of memory conditions, removal of the region/reserve
533 	 * map could fail.  Correspondingly, the subpool and global
534 	 * reserve usage count can need to be adjusted.
535 	 */
536 	VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio);
537 	hugetlb_delete_from_page_cache(folio);
538 	ret = true;
539 	if (!truncate_op) {
540 		if (unlikely(hugetlb_unreserve_pages(inode, index,
541 							index + 1, 1)))
542 			hugetlb_fix_reserve_counts(inode);
543 	}
544 
545 	folio_unlock(folio);
546 	return ret;
547 }
548 
549 /*
550  * remove_inode_hugepages handles two distinct cases: truncation and hole
551  * punch.  There are subtle differences in operation for each case.
552  *
553  * truncation is indicated by end of range being LLONG_MAX
554  *	In this case, we first scan the range and release found pages.
555  *	After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
556  *	maps and global counts.  Page faults can race with truncation.
557  *	During faults, hugetlb_no_page() checks i_size before page allocation,
558  *	and again after obtaining page table lock.  It will 'back out'
559  *	allocations in the truncated range.
560  * hole punch is indicated if end is not LLONG_MAX
561  *	In the hole punch case we scan the range and release found pages.
562  *	Only when releasing a page is the associated region/reserve map
563  *	deleted.  The region/reserve map for ranges without associated
564  *	pages are not modified.  Page faults can race with hole punch.
565  *	This is indicated if we find a mapped page.
566  * Note: If the passed end of range value is beyond the end of file, but
567  * not LLONG_MAX this routine still performs a hole punch operation.
568  */
remove_inode_hugepages(struct inode * inode,loff_t lstart,loff_t lend)569 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
570 				   loff_t lend)
571 {
572 	struct hstate *h = hstate_inode(inode);
573 	struct address_space *mapping = &inode->i_data;
574 	const pgoff_t end = lend >> PAGE_SHIFT;
575 	struct folio_batch fbatch;
576 	pgoff_t next, index;
577 	int i, freed = 0;
578 	bool truncate_op = (lend == LLONG_MAX);
579 
580 	folio_batch_init(&fbatch);
581 	next = lstart >> PAGE_SHIFT;
582 	while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) {
583 		for (i = 0; i < folio_batch_count(&fbatch); ++i) {
584 			struct folio *folio = fbatch.folios[i];
585 			u32 hash = 0;
586 
587 			index = folio->index >> huge_page_order(h);
588 			hash = hugetlb_fault_mutex_hash(mapping, index);
589 			mutex_lock(&hugetlb_fault_mutex_table[hash]);
590 
591 			/*
592 			 * Remove folio that was part of folio_batch.
593 			 */
594 			if (remove_inode_single_folio(h, inode, mapping, folio,
595 							index, truncate_op))
596 				freed++;
597 
598 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
599 		}
600 		folio_batch_release(&fbatch);
601 		cond_resched();
602 	}
603 
604 	if (truncate_op)
605 		(void)hugetlb_unreserve_pages(inode,
606 				lstart >> huge_page_shift(h),
607 				LONG_MAX, freed);
608 }
609 
hugetlbfs_evict_inode(struct inode * inode)610 static void hugetlbfs_evict_inode(struct inode *inode)
611 {
612 	struct resv_map *resv_map;
613 
614 	trace_hugetlbfs_evict_inode(inode);
615 	remove_inode_hugepages(inode, 0, LLONG_MAX);
616 
617 	/*
618 	 * Get the resv_map from the address space embedded in the inode.
619 	 * This is the address space which points to any resv_map allocated
620 	 * at inode creation time.  If this is a device special inode,
621 	 * i_mapping may not point to the original address space.
622 	 */
623 	resv_map = (struct resv_map *)(&inode->i_data)->i_private_data;
624 	/* Only regular and link inodes have associated reserve maps */
625 	if (resv_map)
626 		resv_map_release(&resv_map->refs);
627 	clear_inode(inode);
628 }
629 
hugetlb_vmtruncate(struct inode * inode,loff_t offset)630 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
631 {
632 	pgoff_t pgoff;
633 	struct address_space *mapping = inode->i_mapping;
634 	struct hstate *h = hstate_inode(inode);
635 
636 	BUG_ON(offset & ~huge_page_mask(h));
637 	pgoff = offset >> PAGE_SHIFT;
638 
639 	i_size_write(inode, offset);
640 	i_mmap_lock_write(mapping);
641 	if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
642 		hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
643 				      ZAP_FLAG_DROP_MARKER);
644 	i_mmap_unlock_write(mapping);
645 	remove_inode_hugepages(inode, offset, LLONG_MAX);
646 }
647 
hugetlbfs_zero_partial_page(struct hstate * h,struct address_space * mapping,loff_t start,loff_t end)648 static void hugetlbfs_zero_partial_page(struct hstate *h,
649 					struct address_space *mapping,
650 					loff_t start,
651 					loff_t end)
652 {
653 	pgoff_t idx = start >> huge_page_shift(h);
654 	struct folio *folio;
655 
656 	folio = filemap_lock_hugetlb_folio(h, mapping, idx);
657 	if (IS_ERR(folio))
658 		return;
659 
660 	start = start & ~huge_page_mask(h);
661 	end = end & ~huge_page_mask(h);
662 	if (!end)
663 		end = huge_page_size(h);
664 
665 	folio_zero_segment(folio, (size_t)start, (size_t)end);
666 
667 	folio_unlock(folio);
668 	folio_put(folio);
669 }
670 
hugetlbfs_punch_hole(struct inode * inode,loff_t offset,loff_t len)671 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
672 {
673 	struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
674 	struct address_space *mapping = inode->i_mapping;
675 	struct hstate *h = hstate_inode(inode);
676 	loff_t hpage_size = huge_page_size(h);
677 	loff_t hole_start, hole_end;
678 
679 	/*
680 	 * hole_start and hole_end indicate the full pages within the hole.
681 	 */
682 	hole_start = round_up(offset, hpage_size);
683 	hole_end = round_down(offset + len, hpage_size);
684 
685 	inode_lock(inode);
686 
687 	/* protected by i_rwsem */
688 	if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
689 		inode_unlock(inode);
690 		return -EPERM;
691 	}
692 
693 	i_mmap_lock_write(mapping);
694 
695 	/* If range starts before first full page, zero partial page. */
696 	if (offset < hole_start)
697 		hugetlbfs_zero_partial_page(h, mapping,
698 				offset, min(offset + len, hole_start));
699 
700 	/* Unmap users of full pages in the hole. */
701 	if (hole_end > hole_start) {
702 		if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
703 			hugetlb_vmdelete_list(&mapping->i_mmap,
704 					      hole_start >> PAGE_SHIFT,
705 					      hole_end >> PAGE_SHIFT, 0);
706 	}
707 
708 	/* If range extends beyond last full page, zero partial page. */
709 	if ((offset + len) > hole_end && (offset + len) > hole_start)
710 		hugetlbfs_zero_partial_page(h, mapping,
711 				hole_end, offset + len);
712 
713 	i_mmap_unlock_write(mapping);
714 
715 	/* Remove full pages from the file. */
716 	if (hole_end > hole_start)
717 		remove_inode_hugepages(inode, hole_start, hole_end);
718 
719 	inode_unlock(inode);
720 
721 	return 0;
722 }
723 
hugetlbfs_fallocate(struct file * file,int mode,loff_t offset,loff_t len)724 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
725 				loff_t len)
726 {
727 	struct inode *inode = file_inode(file);
728 	struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
729 	struct address_space *mapping = inode->i_mapping;
730 	struct hstate *h = hstate_inode(inode);
731 	struct vm_area_struct pseudo_vma;
732 	struct mm_struct *mm = current->mm;
733 	loff_t hpage_size = huge_page_size(h);
734 	unsigned long hpage_shift = huge_page_shift(h);
735 	pgoff_t start, index, end;
736 	int error;
737 	u32 hash;
738 
739 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
740 		return -EOPNOTSUPP;
741 
742 	if (mode & FALLOC_FL_PUNCH_HOLE) {
743 		error = hugetlbfs_punch_hole(inode, offset, len);
744 		goto out_nolock;
745 	}
746 
747 	/*
748 	 * Default preallocate case.
749 	 * For this range, start is rounded down and end is rounded up
750 	 * as well as being converted to page offsets.
751 	 */
752 	start = offset >> hpage_shift;
753 	end = (offset + len + hpage_size - 1) >> hpage_shift;
754 
755 	inode_lock(inode);
756 
757 	/* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
758 	error = inode_newsize_ok(inode, offset + len);
759 	if (error)
760 		goto out;
761 
762 	if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
763 		error = -EPERM;
764 		goto out;
765 	}
766 
767 	/*
768 	 * Initialize a pseudo vma as this is required by the huge page
769 	 * allocation routines.
770 	 */
771 	vma_init(&pseudo_vma, mm);
772 	vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
773 	pseudo_vma.vm_file = file;
774 
775 	for (index = start; index < end; index++) {
776 		/*
777 		 * This is supposed to be the vaddr where the page is being
778 		 * faulted in, but we have no vaddr here.
779 		 */
780 		struct folio *folio;
781 		unsigned long addr;
782 
783 		cond_resched();
784 
785 		/*
786 		 * fallocate(2) manpage permits EINTR; we may have been
787 		 * interrupted because we are using up too much memory.
788 		 */
789 		if (signal_pending(current)) {
790 			error = -EINTR;
791 			break;
792 		}
793 
794 		/* addr is the offset within the file (zero based) */
795 		addr = index * hpage_size;
796 
797 		/* mutex taken here, fault path and hole punch */
798 		hash = hugetlb_fault_mutex_hash(mapping, index);
799 		mutex_lock(&hugetlb_fault_mutex_table[hash]);
800 
801 		/* See if already present in mapping to avoid alloc/free */
802 		folio = filemap_get_folio(mapping, index << huge_page_order(h));
803 		if (!IS_ERR(folio)) {
804 			folio_put(folio);
805 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
806 			continue;
807 		}
808 
809 		/*
810 		 * Allocate folio without setting the avoid_reserve argument.
811 		 * There certainly are no reserves associated with the
812 		 * pseudo_vma.  However, there could be shared mappings with
813 		 * reserves for the file at the inode level.  If we fallocate
814 		 * folios in these areas, we need to consume the reserves
815 		 * to keep reservation accounting consistent.
816 		 */
817 		folio = alloc_hugetlb_folio(&pseudo_vma, addr, false);
818 		if (IS_ERR(folio)) {
819 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
820 			error = PTR_ERR(folio);
821 			goto out;
822 		}
823 		folio_zero_user(folio, addr);
824 		__folio_mark_uptodate(folio);
825 		error = hugetlb_add_to_page_cache(folio, mapping, index);
826 		if (unlikely(error)) {
827 			restore_reserve_on_error(h, &pseudo_vma, addr, folio);
828 			folio_put(folio);
829 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
830 			goto out;
831 		}
832 
833 		mutex_unlock(&hugetlb_fault_mutex_table[hash]);
834 
835 		folio_set_hugetlb_migratable(folio);
836 		/*
837 		 * folio_unlock because locked by hugetlb_add_to_page_cache()
838 		 * folio_put() due to reference from alloc_hugetlb_folio()
839 		 */
840 		folio_unlock(folio);
841 		folio_put(folio);
842 	}
843 
844 	if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
845 		i_size_write(inode, offset + len);
846 	inode_set_ctime_current(inode);
847 out:
848 	inode_unlock(inode);
849 
850 out_nolock:
851 	trace_hugetlbfs_fallocate(inode, mode, offset, len, error);
852 	return error;
853 }
854 
hugetlbfs_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * attr)855 static int hugetlbfs_setattr(struct mnt_idmap *idmap,
856 			     struct dentry *dentry, struct iattr *attr)
857 {
858 	struct inode *inode = d_inode(dentry);
859 	struct hstate *h = hstate_inode(inode);
860 	int error;
861 	unsigned int ia_valid = attr->ia_valid;
862 	struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
863 
864 	error = setattr_prepare(idmap, dentry, attr);
865 	if (error)
866 		return error;
867 
868 	trace_hugetlbfs_setattr(inode, dentry, attr);
869 
870 	if (ia_valid & ATTR_SIZE) {
871 		loff_t oldsize = inode->i_size;
872 		loff_t newsize = attr->ia_size;
873 
874 		if (newsize & ~huge_page_mask(h))
875 			return -EINVAL;
876 		/* protected by i_rwsem */
877 		if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
878 		    (newsize > oldsize && (info->seals & F_SEAL_GROW)))
879 			return -EPERM;
880 		hugetlb_vmtruncate(inode, newsize);
881 	}
882 
883 	setattr_copy(idmap, inode, attr);
884 	mark_inode_dirty(inode);
885 	return 0;
886 }
887 
hugetlbfs_get_root(struct super_block * sb,struct hugetlbfs_fs_context * ctx)888 static struct inode *hugetlbfs_get_root(struct super_block *sb,
889 					struct hugetlbfs_fs_context *ctx)
890 {
891 	struct inode *inode;
892 
893 	inode = new_inode(sb);
894 	if (inode) {
895 		inode->i_ino = get_next_ino();
896 		inode->i_mode = S_IFDIR | ctx->mode;
897 		inode->i_uid = ctx->uid;
898 		inode->i_gid = ctx->gid;
899 		simple_inode_init_ts(inode);
900 		inode->i_op = &hugetlbfs_dir_inode_operations;
901 		inode->i_fop = &simple_dir_operations;
902 		/* directory inodes start off with i_nlink == 2 (for "." entry) */
903 		inc_nlink(inode);
904 		lockdep_annotate_inode_mutex_key(inode);
905 	}
906 	return inode;
907 }
908 
909 /*
910  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
911  * be taken from reclaim -- unlike regular filesystems. This needs an
912  * annotation because huge_pmd_share() does an allocation under hugetlb's
913  * i_mmap_rwsem.
914  */
915 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
916 
hugetlbfs_get_inode(struct super_block * sb,struct mnt_idmap * idmap,struct inode * dir,umode_t mode,dev_t dev)917 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
918 					struct mnt_idmap *idmap,
919 					struct inode *dir,
920 					umode_t mode, dev_t dev)
921 {
922 	struct inode *inode;
923 	struct resv_map *resv_map = NULL;
924 
925 	/*
926 	 * Reserve maps are only needed for inodes that can have associated
927 	 * page allocations.
928 	 */
929 	if (S_ISREG(mode) || S_ISLNK(mode)) {
930 		resv_map = resv_map_alloc();
931 		if (!resv_map)
932 			return NULL;
933 	}
934 
935 	inode = new_inode(sb);
936 	if (inode) {
937 		struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
938 
939 		inode->i_ino = get_next_ino();
940 		inode_init_owner(idmap, inode, dir, mode);
941 		lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
942 				&hugetlbfs_i_mmap_rwsem_key);
943 		inode->i_mapping->a_ops = &hugetlbfs_aops;
944 		simple_inode_init_ts(inode);
945 		inode->i_mapping->i_private_data = resv_map;
946 		info->seals = F_SEAL_SEAL;
947 		switch (mode & S_IFMT) {
948 		default:
949 			init_special_inode(inode, mode, dev);
950 			break;
951 		case S_IFREG:
952 			inode->i_op = &hugetlbfs_inode_operations;
953 			inode->i_fop = &hugetlbfs_file_operations;
954 			break;
955 		case S_IFDIR:
956 			inode->i_op = &hugetlbfs_dir_inode_operations;
957 			inode->i_fop = &simple_dir_operations;
958 
959 			/* directory inodes start off with i_nlink == 2 (for "." entry) */
960 			inc_nlink(inode);
961 			break;
962 		case S_IFLNK:
963 			inode->i_op = &page_symlink_inode_operations;
964 			inode_nohighmem(inode);
965 			break;
966 		}
967 		lockdep_annotate_inode_mutex_key(inode);
968 		trace_hugetlbfs_alloc_inode(inode, dir, mode);
969 	} else {
970 		if (resv_map)
971 			kref_put(&resv_map->refs, resv_map_release);
972 	}
973 
974 	return inode;
975 }
976 
977 /*
978  * File creation. Allocate an inode, and we're done..
979  */
hugetlbfs_mknod(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t dev)980 static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
981 			   struct dentry *dentry, umode_t mode, dev_t dev)
982 {
983 	struct inode *inode;
984 
985 	inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, dev);
986 	if (!inode)
987 		return -ENOSPC;
988 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
989 	d_instantiate(dentry, inode);
990 	dget(dentry);/* Extra count - pin the dentry in core */
991 	return 0;
992 }
993 
hugetlbfs_mkdir(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode)994 static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
995 			   struct dentry *dentry, umode_t mode)
996 {
997 	int retval = hugetlbfs_mknod(idmap, dir, dentry,
998 				     mode | S_IFDIR, 0);
999 	if (!retval)
1000 		inc_nlink(dir);
1001 	return retval;
1002 }
1003 
hugetlbfs_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)1004 static int hugetlbfs_create(struct mnt_idmap *idmap,
1005 			    struct inode *dir, struct dentry *dentry,
1006 			    umode_t mode, bool excl)
1007 {
1008 	return hugetlbfs_mknod(idmap, dir, dentry, mode | S_IFREG, 0);
1009 }
1010 
hugetlbfs_tmpfile(struct mnt_idmap * idmap,struct inode * dir,struct file * file,umode_t mode)1011 static int hugetlbfs_tmpfile(struct mnt_idmap *idmap,
1012 			     struct inode *dir, struct file *file,
1013 			     umode_t mode)
1014 {
1015 	struct inode *inode;
1016 
1017 	inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode | S_IFREG, 0);
1018 	if (!inode)
1019 		return -ENOSPC;
1020 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1021 	d_tmpfile(file, inode);
1022 	return finish_open_simple(file, 0);
1023 }
1024 
hugetlbfs_symlink(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,const char * symname)1025 static int hugetlbfs_symlink(struct mnt_idmap *idmap,
1026 			     struct inode *dir, struct dentry *dentry,
1027 			     const char *symname)
1028 {
1029 	const umode_t mode = S_IFLNK|S_IRWXUGO;
1030 	struct inode *inode;
1031 	int error = -ENOSPC;
1032 
1033 	inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, 0);
1034 	if (inode) {
1035 		int l = strlen(symname)+1;
1036 		error = page_symlink(inode, symname, l);
1037 		if (!error) {
1038 			d_instantiate(dentry, inode);
1039 			dget(dentry);
1040 		} else
1041 			iput(inode);
1042 	}
1043 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1044 
1045 	return error;
1046 }
1047 
1048 #ifdef CONFIG_MIGRATION
hugetlbfs_migrate_folio(struct address_space * mapping,struct folio * dst,struct folio * src,enum migrate_mode mode)1049 static int hugetlbfs_migrate_folio(struct address_space *mapping,
1050 				struct folio *dst, struct folio *src,
1051 				enum migrate_mode mode)
1052 {
1053 	int rc;
1054 
1055 	rc = migrate_huge_page_move_mapping(mapping, dst, src);
1056 	if (rc != MIGRATEPAGE_SUCCESS)
1057 		return rc;
1058 
1059 	if (hugetlb_folio_subpool(src)) {
1060 		hugetlb_set_folio_subpool(dst,
1061 					hugetlb_folio_subpool(src));
1062 		hugetlb_set_folio_subpool(src, NULL);
1063 	}
1064 
1065 	folio_migrate_flags(dst, src);
1066 
1067 	return MIGRATEPAGE_SUCCESS;
1068 }
1069 #else
1070 #define hugetlbfs_migrate_folio NULL
1071 #endif
1072 
hugetlbfs_error_remove_folio(struct address_space * mapping,struct folio * folio)1073 static int hugetlbfs_error_remove_folio(struct address_space *mapping,
1074 				struct folio *folio)
1075 {
1076 	return 0;
1077 }
1078 
1079 /*
1080  * Display the mount options in /proc/mounts.
1081  */
hugetlbfs_show_options(struct seq_file * m,struct dentry * root)1082 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1083 {
1084 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1085 	struct hugepage_subpool *spool = sbinfo->spool;
1086 	unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1087 	unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1088 	char mod;
1089 
1090 	if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1091 		seq_printf(m, ",uid=%u",
1092 			   from_kuid_munged(&init_user_ns, sbinfo->uid));
1093 	if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1094 		seq_printf(m, ",gid=%u",
1095 			   from_kgid_munged(&init_user_ns, sbinfo->gid));
1096 	if (sbinfo->mode != 0755)
1097 		seq_printf(m, ",mode=%o", sbinfo->mode);
1098 	if (sbinfo->max_inodes != -1)
1099 		seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1100 
1101 	hpage_size /= 1024;
1102 	mod = 'K';
1103 	if (hpage_size >= 1024) {
1104 		hpage_size /= 1024;
1105 		mod = 'M';
1106 	}
1107 	seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1108 	if (spool) {
1109 		if (spool->max_hpages != -1)
1110 			seq_printf(m, ",size=%llu",
1111 				   (unsigned long long)spool->max_hpages << hpage_shift);
1112 		if (spool->min_hpages != -1)
1113 			seq_printf(m, ",min_size=%llu",
1114 				   (unsigned long long)spool->min_hpages << hpage_shift);
1115 	}
1116 	return 0;
1117 }
1118 
hugetlbfs_statfs(struct dentry * dentry,struct kstatfs * buf)1119 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1120 {
1121 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1122 	struct hstate *h = hstate_inode(d_inode(dentry));
1123 	u64 id = huge_encode_dev(dentry->d_sb->s_dev);
1124 
1125 	buf->f_fsid = u64_to_fsid(id);
1126 	buf->f_type = HUGETLBFS_MAGIC;
1127 	buf->f_bsize = huge_page_size(h);
1128 	if (sbinfo) {
1129 		spin_lock(&sbinfo->stat_lock);
1130 		/* If no limits set, just report 0 or -1 for max/free/used
1131 		 * blocks, like simple_statfs() */
1132 		if (sbinfo->spool) {
1133 			long free_pages;
1134 
1135 			spin_lock_irq(&sbinfo->spool->lock);
1136 			buf->f_blocks = sbinfo->spool->max_hpages;
1137 			free_pages = sbinfo->spool->max_hpages
1138 				- sbinfo->spool->used_hpages;
1139 			buf->f_bavail = buf->f_bfree = free_pages;
1140 			spin_unlock_irq(&sbinfo->spool->lock);
1141 			buf->f_files = sbinfo->max_inodes;
1142 			buf->f_ffree = sbinfo->free_inodes;
1143 		}
1144 		spin_unlock(&sbinfo->stat_lock);
1145 	}
1146 	buf->f_namelen = NAME_MAX;
1147 	return 0;
1148 }
1149 
hugetlbfs_put_super(struct super_block * sb)1150 static void hugetlbfs_put_super(struct super_block *sb)
1151 {
1152 	struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1153 
1154 	if (sbi) {
1155 		sb->s_fs_info = NULL;
1156 
1157 		if (sbi->spool)
1158 			hugepage_put_subpool(sbi->spool);
1159 
1160 		kfree(sbi);
1161 	}
1162 }
1163 
hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info * sbinfo)1164 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1165 {
1166 	if (sbinfo->free_inodes >= 0) {
1167 		spin_lock(&sbinfo->stat_lock);
1168 		if (unlikely(!sbinfo->free_inodes)) {
1169 			spin_unlock(&sbinfo->stat_lock);
1170 			return 0;
1171 		}
1172 		sbinfo->free_inodes--;
1173 		spin_unlock(&sbinfo->stat_lock);
1174 	}
1175 
1176 	return 1;
1177 }
1178 
hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info * sbinfo)1179 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1180 {
1181 	if (sbinfo->free_inodes >= 0) {
1182 		spin_lock(&sbinfo->stat_lock);
1183 		sbinfo->free_inodes++;
1184 		spin_unlock(&sbinfo->stat_lock);
1185 	}
1186 }
1187 
1188 
1189 static struct kmem_cache *hugetlbfs_inode_cachep;
1190 
hugetlbfs_alloc_inode(struct super_block * sb)1191 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1192 {
1193 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1194 	struct hugetlbfs_inode_info *p;
1195 
1196 	if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1197 		return NULL;
1198 	p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
1199 	if (unlikely(!p)) {
1200 		hugetlbfs_inc_free_inodes(sbinfo);
1201 		return NULL;
1202 	}
1203 	return &p->vfs_inode;
1204 }
1205 
hugetlbfs_free_inode(struct inode * inode)1206 static void hugetlbfs_free_inode(struct inode *inode)
1207 {
1208 	trace_hugetlbfs_free_inode(inode);
1209 	kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1210 }
1211 
hugetlbfs_destroy_inode(struct inode * inode)1212 static void hugetlbfs_destroy_inode(struct inode *inode)
1213 {
1214 	hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1215 }
1216 
1217 static const struct address_space_operations hugetlbfs_aops = {
1218 	.write_begin	= hugetlbfs_write_begin,
1219 	.write_end	= hugetlbfs_write_end,
1220 	.dirty_folio	= noop_dirty_folio,
1221 	.migrate_folio  = hugetlbfs_migrate_folio,
1222 	.error_remove_folio	= hugetlbfs_error_remove_folio,
1223 };
1224 
1225 
init_once(void * foo)1226 static void init_once(void *foo)
1227 {
1228 	struct hugetlbfs_inode_info *ei = foo;
1229 
1230 	inode_init_once(&ei->vfs_inode);
1231 }
1232 
1233 static const struct file_operations hugetlbfs_file_operations = {
1234 	.read_iter		= hugetlbfs_read_iter,
1235 	.mmap			= hugetlbfs_file_mmap,
1236 	.fsync			= noop_fsync,
1237 	.get_unmapped_area	= hugetlb_get_unmapped_area,
1238 	.llseek			= default_llseek,
1239 	.fallocate		= hugetlbfs_fallocate,
1240 	.fop_flags		= FOP_HUGE_PAGES,
1241 };
1242 
1243 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1244 	.create		= hugetlbfs_create,
1245 	.lookup		= simple_lookup,
1246 	.link		= simple_link,
1247 	.unlink		= simple_unlink,
1248 	.symlink	= hugetlbfs_symlink,
1249 	.mkdir		= hugetlbfs_mkdir,
1250 	.rmdir		= simple_rmdir,
1251 	.mknod		= hugetlbfs_mknod,
1252 	.rename		= simple_rename,
1253 	.setattr	= hugetlbfs_setattr,
1254 	.tmpfile	= hugetlbfs_tmpfile,
1255 };
1256 
1257 static const struct inode_operations hugetlbfs_inode_operations = {
1258 	.setattr	= hugetlbfs_setattr,
1259 };
1260 
1261 static const struct super_operations hugetlbfs_ops = {
1262 	.alloc_inode    = hugetlbfs_alloc_inode,
1263 	.free_inode     = hugetlbfs_free_inode,
1264 	.destroy_inode  = hugetlbfs_destroy_inode,
1265 	.evict_inode	= hugetlbfs_evict_inode,
1266 	.statfs		= hugetlbfs_statfs,
1267 	.put_super	= hugetlbfs_put_super,
1268 	.show_options	= hugetlbfs_show_options,
1269 };
1270 
1271 /*
1272  * Convert size option passed from command line to number of huge pages
1273  * in the pool specified by hstate.  Size option could be in bytes
1274  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1275  */
1276 static long
hugetlbfs_size_to_hpages(struct hstate * h,unsigned long long size_opt,enum hugetlbfs_size_type val_type)1277 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1278 			 enum hugetlbfs_size_type val_type)
1279 {
1280 	if (val_type == NO_SIZE)
1281 		return -1;
1282 
1283 	if (val_type == SIZE_PERCENT) {
1284 		size_opt <<= huge_page_shift(h);
1285 		size_opt *= h->max_huge_pages;
1286 		do_div(size_opt, 100);
1287 	}
1288 
1289 	size_opt >>= huge_page_shift(h);
1290 	return size_opt;
1291 }
1292 
1293 /*
1294  * Parse one mount parameter.
1295  */
hugetlbfs_parse_param(struct fs_context * fc,struct fs_parameter * param)1296 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1297 {
1298 	struct hugetlbfs_fs_context *ctx = fc->fs_private;
1299 	struct fs_parse_result result;
1300 	struct hstate *h;
1301 	char *rest;
1302 	unsigned long ps;
1303 	int opt;
1304 
1305 	opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1306 	if (opt < 0)
1307 		return opt;
1308 
1309 	switch (opt) {
1310 	case Opt_uid:
1311 		ctx->uid = result.uid;
1312 		return 0;
1313 
1314 	case Opt_gid:
1315 		ctx->gid = result.gid;
1316 		return 0;
1317 
1318 	case Opt_mode:
1319 		ctx->mode = result.uint_32 & 01777U;
1320 		return 0;
1321 
1322 	case Opt_size:
1323 		/* memparse() will accept a K/M/G without a digit */
1324 		if (!param->string || !isdigit(param->string[0]))
1325 			goto bad_val;
1326 		ctx->max_size_opt = memparse(param->string, &rest);
1327 		ctx->max_val_type = SIZE_STD;
1328 		if (*rest == '%')
1329 			ctx->max_val_type = SIZE_PERCENT;
1330 		return 0;
1331 
1332 	case Opt_nr_inodes:
1333 		/* memparse() will accept a K/M/G without a digit */
1334 		if (!param->string || !isdigit(param->string[0]))
1335 			goto bad_val;
1336 		ctx->nr_inodes = memparse(param->string, &rest);
1337 		return 0;
1338 
1339 	case Opt_pagesize:
1340 		ps = memparse(param->string, &rest);
1341 		h = size_to_hstate(ps);
1342 		if (!h) {
1343 			pr_err("Unsupported page size %lu MB\n", ps / SZ_1M);
1344 			return -EINVAL;
1345 		}
1346 		ctx->hstate = h;
1347 		return 0;
1348 
1349 	case Opt_min_size:
1350 		/* memparse() will accept a K/M/G without a digit */
1351 		if (!param->string || !isdigit(param->string[0]))
1352 			goto bad_val;
1353 		ctx->min_size_opt = memparse(param->string, &rest);
1354 		ctx->min_val_type = SIZE_STD;
1355 		if (*rest == '%')
1356 			ctx->min_val_type = SIZE_PERCENT;
1357 		return 0;
1358 
1359 	default:
1360 		return -EINVAL;
1361 	}
1362 
1363 bad_val:
1364 	return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1365 		      param->string, param->key);
1366 }
1367 
1368 /*
1369  * Validate the parsed options.
1370  */
hugetlbfs_validate(struct fs_context * fc)1371 static int hugetlbfs_validate(struct fs_context *fc)
1372 {
1373 	struct hugetlbfs_fs_context *ctx = fc->fs_private;
1374 
1375 	/*
1376 	 * Use huge page pool size (in hstate) to convert the size
1377 	 * options to number of huge pages.  If NO_SIZE, -1 is returned.
1378 	 */
1379 	ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1380 						   ctx->max_size_opt,
1381 						   ctx->max_val_type);
1382 	ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1383 						   ctx->min_size_opt,
1384 						   ctx->min_val_type);
1385 
1386 	/*
1387 	 * If max_size was specified, then min_size must be smaller
1388 	 */
1389 	if (ctx->max_val_type > NO_SIZE &&
1390 	    ctx->min_hpages > ctx->max_hpages) {
1391 		pr_err("Minimum size can not be greater than maximum size\n");
1392 		return -EINVAL;
1393 	}
1394 
1395 	return 0;
1396 }
1397 
1398 static int
hugetlbfs_fill_super(struct super_block * sb,struct fs_context * fc)1399 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1400 {
1401 	struct hugetlbfs_fs_context *ctx = fc->fs_private;
1402 	struct hugetlbfs_sb_info *sbinfo;
1403 
1404 	sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1405 	if (!sbinfo)
1406 		return -ENOMEM;
1407 	sb->s_fs_info = sbinfo;
1408 	spin_lock_init(&sbinfo->stat_lock);
1409 	sbinfo->hstate		= ctx->hstate;
1410 	sbinfo->max_inodes	= ctx->nr_inodes;
1411 	sbinfo->free_inodes	= ctx->nr_inodes;
1412 	sbinfo->spool		= NULL;
1413 	sbinfo->uid		= ctx->uid;
1414 	sbinfo->gid		= ctx->gid;
1415 	sbinfo->mode		= ctx->mode;
1416 
1417 	/*
1418 	 * Allocate and initialize subpool if maximum or minimum size is
1419 	 * specified.  Any needed reservations (for minimum size) are taken
1420 	 * when the subpool is created.
1421 	 */
1422 	if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1423 		sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1424 						     ctx->max_hpages,
1425 						     ctx->min_hpages);
1426 		if (!sbinfo->spool)
1427 			goto out_free;
1428 	}
1429 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1430 	sb->s_blocksize = huge_page_size(ctx->hstate);
1431 	sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1432 	sb->s_magic = HUGETLBFS_MAGIC;
1433 	sb->s_op = &hugetlbfs_ops;
1434 	sb->s_time_gran = 1;
1435 
1436 	/*
1437 	 * Due to the special and limited functionality of hugetlbfs, it does
1438 	 * not work well as a stacking filesystem.
1439 	 */
1440 	sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1441 	sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1442 	if (!sb->s_root)
1443 		goto out_free;
1444 	return 0;
1445 out_free:
1446 	kfree(sbinfo->spool);
1447 	kfree(sbinfo);
1448 	return -ENOMEM;
1449 }
1450 
hugetlbfs_get_tree(struct fs_context * fc)1451 static int hugetlbfs_get_tree(struct fs_context *fc)
1452 {
1453 	int err = hugetlbfs_validate(fc);
1454 	if (err)
1455 		return err;
1456 	return get_tree_nodev(fc, hugetlbfs_fill_super);
1457 }
1458 
hugetlbfs_fs_context_free(struct fs_context * fc)1459 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1460 {
1461 	kfree(fc->fs_private);
1462 }
1463 
1464 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1465 	.free		= hugetlbfs_fs_context_free,
1466 	.parse_param	= hugetlbfs_parse_param,
1467 	.get_tree	= hugetlbfs_get_tree,
1468 };
1469 
hugetlbfs_init_fs_context(struct fs_context * fc)1470 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1471 {
1472 	struct hugetlbfs_fs_context *ctx;
1473 
1474 	ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1475 	if (!ctx)
1476 		return -ENOMEM;
1477 
1478 	ctx->max_hpages	= -1; /* No limit on size by default */
1479 	ctx->nr_inodes	= -1; /* No limit on number of inodes by default */
1480 	ctx->uid	= current_fsuid();
1481 	ctx->gid	= current_fsgid();
1482 	ctx->mode	= 0755;
1483 	ctx->hstate	= &default_hstate;
1484 	ctx->min_hpages	= -1; /* No default minimum size */
1485 	ctx->max_val_type = NO_SIZE;
1486 	ctx->min_val_type = NO_SIZE;
1487 	fc->fs_private = ctx;
1488 	fc->ops	= &hugetlbfs_fs_context_ops;
1489 	return 0;
1490 }
1491 
1492 static struct file_system_type hugetlbfs_fs_type = {
1493 	.name			= "hugetlbfs",
1494 	.init_fs_context	= hugetlbfs_init_fs_context,
1495 	.parameters		= hugetlb_fs_parameters,
1496 	.kill_sb		= kill_litter_super,
1497 	.fs_flags               = FS_ALLOW_IDMAP,
1498 };
1499 
1500 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1501 
can_do_hugetlb_shm(void)1502 static int can_do_hugetlb_shm(void)
1503 {
1504 	kgid_t shm_group;
1505 	shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1506 	return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1507 }
1508 
get_hstate_idx(int page_size_log)1509 static int get_hstate_idx(int page_size_log)
1510 {
1511 	struct hstate *h = hstate_sizelog(page_size_log);
1512 
1513 	if (!h)
1514 		return -1;
1515 	return hstate_index(h);
1516 }
1517 
1518 /*
1519  * Note that size should be aligned to proper hugepage size in caller side,
1520  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1521  */
hugetlb_file_setup(const char * name,size_t size,vm_flags_t acctflag,int creat_flags,int page_size_log)1522 struct file *hugetlb_file_setup(const char *name, size_t size,
1523 				vm_flags_t acctflag, int creat_flags,
1524 				int page_size_log)
1525 {
1526 	struct inode *inode;
1527 	struct vfsmount *mnt;
1528 	int hstate_idx;
1529 	struct file *file;
1530 
1531 	hstate_idx = get_hstate_idx(page_size_log);
1532 	if (hstate_idx < 0)
1533 		return ERR_PTR(-ENODEV);
1534 
1535 	mnt = hugetlbfs_vfsmount[hstate_idx];
1536 	if (!mnt)
1537 		return ERR_PTR(-ENOENT);
1538 
1539 	if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1540 		struct ucounts *ucounts = current_ucounts();
1541 
1542 		if (user_shm_lock(size, ucounts)) {
1543 			pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
1544 				current->comm, current->pid);
1545 			user_shm_unlock(size, ucounts);
1546 		}
1547 		return ERR_PTR(-EPERM);
1548 	}
1549 
1550 	file = ERR_PTR(-ENOSPC);
1551 	/* hugetlbfs_vfsmount[] mounts do not use idmapped mounts.  */
1552 	inode = hugetlbfs_get_inode(mnt->mnt_sb, &nop_mnt_idmap, NULL,
1553 				    S_IFREG | S_IRWXUGO, 0);
1554 	if (!inode)
1555 		goto out;
1556 	if (creat_flags == HUGETLB_SHMFS_INODE)
1557 		inode->i_flags |= S_PRIVATE;
1558 
1559 	inode->i_size = size;
1560 	clear_nlink(inode);
1561 
1562 	if (!hugetlb_reserve_pages(inode, 0,
1563 			size >> huge_page_shift(hstate_inode(inode)), NULL,
1564 			acctflag))
1565 		file = ERR_PTR(-ENOMEM);
1566 	else
1567 		file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1568 					&hugetlbfs_file_operations);
1569 	if (!IS_ERR(file))
1570 		return file;
1571 
1572 	iput(inode);
1573 out:
1574 	return file;
1575 }
1576 
mount_one_hugetlbfs(struct hstate * h)1577 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1578 {
1579 	struct fs_context *fc;
1580 	struct vfsmount *mnt;
1581 
1582 	fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1583 	if (IS_ERR(fc)) {
1584 		mnt = ERR_CAST(fc);
1585 	} else {
1586 		struct hugetlbfs_fs_context *ctx = fc->fs_private;
1587 		ctx->hstate = h;
1588 		mnt = fc_mount(fc);
1589 		put_fs_context(fc);
1590 	}
1591 	if (IS_ERR(mnt))
1592 		pr_err("Cannot mount internal hugetlbfs for page size %luK",
1593 		       huge_page_size(h) / SZ_1K);
1594 	return mnt;
1595 }
1596 
init_hugetlbfs_fs(void)1597 static int __init init_hugetlbfs_fs(void)
1598 {
1599 	struct vfsmount *mnt;
1600 	struct hstate *h;
1601 	int error;
1602 	int i;
1603 
1604 	if (!hugepages_supported()) {
1605 		pr_info("disabling because there are no supported hugepage sizes\n");
1606 		return -ENOTSUPP;
1607 	}
1608 
1609 	error = -ENOMEM;
1610 	hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1611 					sizeof(struct hugetlbfs_inode_info),
1612 					0, SLAB_ACCOUNT, init_once);
1613 	if (hugetlbfs_inode_cachep == NULL)
1614 		goto out;
1615 
1616 	error = register_filesystem(&hugetlbfs_fs_type);
1617 	if (error)
1618 		goto out_free;
1619 
1620 	/* default hstate mount is required */
1621 	mnt = mount_one_hugetlbfs(&default_hstate);
1622 	if (IS_ERR(mnt)) {
1623 		error = PTR_ERR(mnt);
1624 		goto out_unreg;
1625 	}
1626 	hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1627 
1628 	/* other hstates are optional */
1629 	i = 0;
1630 	for_each_hstate(h) {
1631 		if (i == default_hstate_idx) {
1632 			i++;
1633 			continue;
1634 		}
1635 
1636 		mnt = mount_one_hugetlbfs(h);
1637 		if (IS_ERR(mnt))
1638 			hugetlbfs_vfsmount[i] = NULL;
1639 		else
1640 			hugetlbfs_vfsmount[i] = mnt;
1641 		i++;
1642 	}
1643 
1644 	return 0;
1645 
1646  out_unreg:
1647 	(void)unregister_filesystem(&hugetlbfs_fs_type);
1648  out_free:
1649 	kmem_cache_destroy(hugetlbfs_inode_cachep);
1650  out:
1651 	return error;
1652 }
1653 fs_initcall(init_hugetlbfs_fs)
1654