xref: /openbmc/linux/fs/hugetlbfs/inode.c (revision c8dbaa22)
1 /*
2  * hugetlbpage-backed filesystem.  Based on ramfs.
3  *
4  * Nadia Yvette Chambers, 2002
5  *
6  * Copyright (C) 2002 Linus Torvalds.
7  * License: GPL
8  */
9 
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 
12 #include <linux/thread_info.h>
13 #include <asm/current.h>
14 #include <linux/sched/signal.h>		/* remove ASAP */
15 #include <linux/falloc.h>
16 #include <linux/fs.h>
17 #include <linux/mount.h>
18 #include <linux/file.h>
19 #include <linux/kernel.h>
20 #include <linux/writeback.h>
21 #include <linux/pagemap.h>
22 #include <linux/highmem.h>
23 #include <linux/init.h>
24 #include <linux/string.h>
25 #include <linux/capability.h>
26 #include <linux/ctype.h>
27 #include <linux/backing-dev.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagevec.h>
30 #include <linux/parser.h>
31 #include <linux/mman.h>
32 #include <linux/slab.h>
33 #include <linux/dnotify.h>
34 #include <linux/statfs.h>
35 #include <linux/security.h>
36 #include <linux/magic.h>
37 #include <linux/migrate.h>
38 #include <linux/uio.h>
39 
40 #include <linux/uaccess.h>
41 
42 static const struct super_operations hugetlbfs_ops;
43 static const struct address_space_operations hugetlbfs_aops;
44 const struct file_operations hugetlbfs_file_operations;
45 static const struct inode_operations hugetlbfs_dir_inode_operations;
46 static const struct inode_operations hugetlbfs_inode_operations;
47 
48 struct hugetlbfs_config {
49 	struct hstate		*hstate;
50 	long			max_hpages;
51 	long			nr_inodes;
52 	long			min_hpages;
53 	kuid_t			uid;
54 	kgid_t			gid;
55 	umode_t			mode;
56 };
57 
58 struct hugetlbfs_inode_info {
59 	struct shared_policy policy;
60 	struct inode vfs_inode;
61 };
62 
63 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
64 {
65 	return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
66 }
67 
68 int sysctl_hugetlb_shm_group;
69 
70 enum {
71 	Opt_size, Opt_nr_inodes,
72 	Opt_mode, Opt_uid, Opt_gid,
73 	Opt_pagesize, Opt_min_size,
74 	Opt_err,
75 };
76 
77 static const match_table_t tokens = {
78 	{Opt_size,	"size=%s"},
79 	{Opt_nr_inodes,	"nr_inodes=%s"},
80 	{Opt_mode,	"mode=%o"},
81 	{Opt_uid,	"uid=%u"},
82 	{Opt_gid,	"gid=%u"},
83 	{Opt_pagesize,	"pagesize=%s"},
84 	{Opt_min_size,	"min_size=%s"},
85 	{Opt_err,	NULL},
86 };
87 
88 #ifdef CONFIG_NUMA
89 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
90 					struct inode *inode, pgoff_t index)
91 {
92 	vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
93 							index);
94 }
95 
96 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
97 {
98 	mpol_cond_put(vma->vm_policy);
99 }
100 #else
101 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
102 					struct inode *inode, pgoff_t index)
103 {
104 }
105 
106 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
107 {
108 }
109 #endif
110 
111 static void huge_pagevec_release(struct pagevec *pvec)
112 {
113 	int i;
114 
115 	for (i = 0; i < pagevec_count(pvec); ++i)
116 		put_page(pvec->pages[i]);
117 
118 	pagevec_reinit(pvec);
119 }
120 
121 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
122 {
123 	struct inode *inode = file_inode(file);
124 	loff_t len, vma_len;
125 	int ret;
126 	struct hstate *h = hstate_file(file);
127 
128 	/*
129 	 * vma address alignment (but not the pgoff alignment) has
130 	 * already been checked by prepare_hugepage_range.  If you add
131 	 * any error returns here, do so after setting VM_HUGETLB, so
132 	 * is_vm_hugetlb_page tests below unmap_region go the right
133 	 * way when do_mmap_pgoff unwinds (may be important on powerpc
134 	 * and ia64).
135 	 */
136 	vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
137 	vma->vm_ops = &hugetlb_vm_ops;
138 
139 	/*
140 	 * Offset passed to mmap (before page shift) could have been
141 	 * negative when represented as a (l)off_t.
142 	 */
143 	if (((loff_t)vma->vm_pgoff << PAGE_SHIFT) < 0)
144 		return -EINVAL;
145 
146 	if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
147 		return -EINVAL;
148 
149 	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
150 	len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
151 	/* check for overflow */
152 	if (len < vma_len)
153 		return -EINVAL;
154 
155 	inode_lock(inode);
156 	file_accessed(file);
157 
158 	ret = -ENOMEM;
159 	if (hugetlb_reserve_pages(inode,
160 				vma->vm_pgoff >> huge_page_order(h),
161 				len >> huge_page_shift(h), vma,
162 				vma->vm_flags))
163 		goto out;
164 
165 	ret = 0;
166 	if (vma->vm_flags & VM_WRITE && inode->i_size < len)
167 		i_size_write(inode, len);
168 out:
169 	inode_unlock(inode);
170 
171 	return ret;
172 }
173 
174 /*
175  * Called under down_write(mmap_sem).
176  */
177 
178 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
179 static unsigned long
180 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
181 		unsigned long len, unsigned long pgoff, unsigned long flags)
182 {
183 	struct mm_struct *mm = current->mm;
184 	struct vm_area_struct *vma;
185 	struct hstate *h = hstate_file(file);
186 	struct vm_unmapped_area_info info;
187 
188 	if (len & ~huge_page_mask(h))
189 		return -EINVAL;
190 	if (len > TASK_SIZE)
191 		return -ENOMEM;
192 
193 	if (flags & MAP_FIXED) {
194 		if (prepare_hugepage_range(file, addr, len))
195 			return -EINVAL;
196 		return addr;
197 	}
198 
199 	if (addr) {
200 		addr = ALIGN(addr, huge_page_size(h));
201 		vma = find_vma(mm, addr);
202 		if (TASK_SIZE - len >= addr &&
203 		    (!vma || addr + len <= vm_start_gap(vma)))
204 			return addr;
205 	}
206 
207 	info.flags = 0;
208 	info.length = len;
209 	info.low_limit = TASK_UNMAPPED_BASE;
210 	info.high_limit = TASK_SIZE;
211 	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
212 	info.align_offset = 0;
213 	return vm_unmapped_area(&info);
214 }
215 #endif
216 
217 static size_t
218 hugetlbfs_read_actor(struct page *page, unsigned long offset,
219 			struct iov_iter *to, unsigned long size)
220 {
221 	size_t copied = 0;
222 	int i, chunksize;
223 
224 	/* Find which 4k chunk and offset with in that chunk */
225 	i = offset >> PAGE_SHIFT;
226 	offset = offset & ~PAGE_MASK;
227 
228 	while (size) {
229 		size_t n;
230 		chunksize = PAGE_SIZE;
231 		if (offset)
232 			chunksize -= offset;
233 		if (chunksize > size)
234 			chunksize = size;
235 		n = copy_page_to_iter(&page[i], offset, chunksize, to);
236 		copied += n;
237 		if (n != chunksize)
238 			return copied;
239 		offset = 0;
240 		size -= chunksize;
241 		i++;
242 	}
243 	return copied;
244 }
245 
246 /*
247  * Support for read() - Find the page attached to f_mapping and copy out the
248  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
249  * since it has PAGE_SIZE assumptions.
250  */
251 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
252 {
253 	struct file *file = iocb->ki_filp;
254 	struct hstate *h = hstate_file(file);
255 	struct address_space *mapping = file->f_mapping;
256 	struct inode *inode = mapping->host;
257 	unsigned long index = iocb->ki_pos >> huge_page_shift(h);
258 	unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
259 	unsigned long end_index;
260 	loff_t isize;
261 	ssize_t retval = 0;
262 
263 	while (iov_iter_count(to)) {
264 		struct page *page;
265 		size_t nr, copied;
266 
267 		/* nr is the maximum number of bytes to copy from this page */
268 		nr = huge_page_size(h);
269 		isize = i_size_read(inode);
270 		if (!isize)
271 			break;
272 		end_index = (isize - 1) >> huge_page_shift(h);
273 		if (index > end_index)
274 			break;
275 		if (index == end_index) {
276 			nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
277 			if (nr <= offset)
278 				break;
279 		}
280 		nr = nr - offset;
281 
282 		/* Find the page */
283 		page = find_lock_page(mapping, index);
284 		if (unlikely(page == NULL)) {
285 			/*
286 			 * We have a HOLE, zero out the user-buffer for the
287 			 * length of the hole or request.
288 			 */
289 			copied = iov_iter_zero(nr, to);
290 		} else {
291 			unlock_page(page);
292 
293 			/*
294 			 * We have the page, copy it to user space buffer.
295 			 */
296 			copied = hugetlbfs_read_actor(page, offset, to, nr);
297 			put_page(page);
298 		}
299 		offset += copied;
300 		retval += copied;
301 		if (copied != nr && iov_iter_count(to)) {
302 			if (!retval)
303 				retval = -EFAULT;
304 			break;
305 		}
306 		index += offset >> huge_page_shift(h);
307 		offset &= ~huge_page_mask(h);
308 	}
309 	iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
310 	return retval;
311 }
312 
313 static int hugetlbfs_write_begin(struct file *file,
314 			struct address_space *mapping,
315 			loff_t pos, unsigned len, unsigned flags,
316 			struct page **pagep, void **fsdata)
317 {
318 	return -EINVAL;
319 }
320 
321 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
322 			loff_t pos, unsigned len, unsigned copied,
323 			struct page *page, void *fsdata)
324 {
325 	BUG();
326 	return -EINVAL;
327 }
328 
329 static void remove_huge_page(struct page *page)
330 {
331 	ClearPageDirty(page);
332 	ClearPageUptodate(page);
333 	delete_from_page_cache(page);
334 }
335 
336 static void
337 hugetlb_vmdelete_list(struct rb_root *root, pgoff_t start, pgoff_t end)
338 {
339 	struct vm_area_struct *vma;
340 
341 	/*
342 	 * end == 0 indicates that the entire range after
343 	 * start should be unmapped.
344 	 */
345 	vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
346 		unsigned long v_offset;
347 		unsigned long v_end;
348 
349 		/*
350 		 * Can the expression below overflow on 32-bit arches?
351 		 * No, because the interval tree returns us only those vmas
352 		 * which overlap the truncated area starting at pgoff,
353 		 * and no vma on a 32-bit arch can span beyond the 4GB.
354 		 */
355 		if (vma->vm_pgoff < start)
356 			v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
357 		else
358 			v_offset = 0;
359 
360 		if (!end)
361 			v_end = vma->vm_end;
362 		else {
363 			v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
364 							+ vma->vm_start;
365 			if (v_end > vma->vm_end)
366 				v_end = vma->vm_end;
367 		}
368 
369 		unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
370 									NULL);
371 	}
372 }
373 
374 /*
375  * remove_inode_hugepages handles two distinct cases: truncation and hole
376  * punch.  There are subtle differences in operation for each case.
377  *
378  * truncation is indicated by end of range being LLONG_MAX
379  *	In this case, we first scan the range and release found pages.
380  *	After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
381  *	maps and global counts.  Page faults can not race with truncation
382  *	in this routine.  hugetlb_no_page() prevents page faults in the
383  *	truncated range.  It checks i_size before allocation, and again after
384  *	with the page table lock for the page held.  The same lock must be
385  *	acquired to unmap a page.
386  * hole punch is indicated if end is not LLONG_MAX
387  *	In the hole punch case we scan the range and release found pages.
388  *	Only when releasing a page is the associated region/reserv map
389  *	deleted.  The region/reserv map for ranges without associated
390  *	pages are not modified.  Page faults can race with hole punch.
391  *	This is indicated if we find a mapped page.
392  * Note: If the passed end of range value is beyond the end of file, but
393  * not LLONG_MAX this routine still performs a hole punch operation.
394  */
395 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
396 				   loff_t lend)
397 {
398 	struct hstate *h = hstate_inode(inode);
399 	struct address_space *mapping = &inode->i_data;
400 	const pgoff_t start = lstart >> huge_page_shift(h);
401 	const pgoff_t end = lend >> huge_page_shift(h);
402 	struct vm_area_struct pseudo_vma;
403 	struct pagevec pvec;
404 	pgoff_t next;
405 	int i, freed = 0;
406 	long lookup_nr = PAGEVEC_SIZE;
407 	bool truncate_op = (lend == LLONG_MAX);
408 
409 	memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
410 	pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
411 	pagevec_init(&pvec, 0);
412 	next = start;
413 	while (next < end) {
414 		/*
415 		 * Don't grab more pages than the number left in the range.
416 		 */
417 		if (end - next < lookup_nr)
418 			lookup_nr = end - next;
419 
420 		/*
421 		 * When no more pages are found, we are done.
422 		 */
423 		if (!pagevec_lookup(&pvec, mapping, next, lookup_nr))
424 			break;
425 
426 		for (i = 0; i < pagevec_count(&pvec); ++i) {
427 			struct page *page = pvec.pages[i];
428 			u32 hash;
429 
430 			/*
431 			 * The page (index) could be beyond end.  This is
432 			 * only possible in the punch hole case as end is
433 			 * max page offset in the truncate case.
434 			 */
435 			next = page->index;
436 			if (next >= end)
437 				break;
438 
439 			hash = hugetlb_fault_mutex_hash(h, current->mm,
440 							&pseudo_vma,
441 							mapping, next, 0);
442 			mutex_lock(&hugetlb_fault_mutex_table[hash]);
443 
444 			/*
445 			 * If page is mapped, it was faulted in after being
446 			 * unmapped in caller.  Unmap (again) now after taking
447 			 * the fault mutex.  The mutex will prevent faults
448 			 * until we finish removing the page.
449 			 *
450 			 * This race can only happen in the hole punch case.
451 			 * Getting here in a truncate operation is a bug.
452 			 */
453 			if (unlikely(page_mapped(page))) {
454 				BUG_ON(truncate_op);
455 
456 				i_mmap_lock_write(mapping);
457 				hugetlb_vmdelete_list(&mapping->i_mmap,
458 					next * pages_per_huge_page(h),
459 					(next + 1) * pages_per_huge_page(h));
460 				i_mmap_unlock_write(mapping);
461 			}
462 
463 			lock_page(page);
464 			/*
465 			 * We must free the huge page and remove from page
466 			 * cache (remove_huge_page) BEFORE removing the
467 			 * region/reserve map (hugetlb_unreserve_pages).  In
468 			 * rare out of memory conditions, removal of the
469 			 * region/reserve map could fail. Correspondingly,
470 			 * the subpool and global reserve usage count can need
471 			 * to be adjusted.
472 			 */
473 			VM_BUG_ON(PagePrivate(page));
474 			remove_huge_page(page);
475 			freed++;
476 			if (!truncate_op) {
477 				if (unlikely(hugetlb_unreserve_pages(inode,
478 							next, next + 1, 1)))
479 					hugetlb_fix_reserve_counts(inode);
480 			}
481 
482 			unlock_page(page);
483 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
484 		}
485 		++next;
486 		huge_pagevec_release(&pvec);
487 		cond_resched();
488 	}
489 
490 	if (truncate_op)
491 		(void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
492 }
493 
494 static void hugetlbfs_evict_inode(struct inode *inode)
495 {
496 	struct resv_map *resv_map;
497 
498 	remove_inode_hugepages(inode, 0, LLONG_MAX);
499 	resv_map = (struct resv_map *)inode->i_mapping->private_data;
500 	/* root inode doesn't have the resv_map, so we should check it */
501 	if (resv_map)
502 		resv_map_release(&resv_map->refs);
503 	clear_inode(inode);
504 }
505 
506 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
507 {
508 	pgoff_t pgoff;
509 	struct address_space *mapping = inode->i_mapping;
510 	struct hstate *h = hstate_inode(inode);
511 
512 	BUG_ON(offset & ~huge_page_mask(h));
513 	pgoff = offset >> PAGE_SHIFT;
514 
515 	i_size_write(inode, offset);
516 	i_mmap_lock_write(mapping);
517 	if (!RB_EMPTY_ROOT(&mapping->i_mmap))
518 		hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
519 	i_mmap_unlock_write(mapping);
520 	remove_inode_hugepages(inode, offset, LLONG_MAX);
521 	return 0;
522 }
523 
524 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
525 {
526 	struct hstate *h = hstate_inode(inode);
527 	loff_t hpage_size = huge_page_size(h);
528 	loff_t hole_start, hole_end;
529 
530 	/*
531 	 * For hole punch round up the beginning offset of the hole and
532 	 * round down the end.
533 	 */
534 	hole_start = round_up(offset, hpage_size);
535 	hole_end = round_down(offset + len, hpage_size);
536 
537 	if (hole_end > hole_start) {
538 		struct address_space *mapping = inode->i_mapping;
539 
540 		inode_lock(inode);
541 		i_mmap_lock_write(mapping);
542 		if (!RB_EMPTY_ROOT(&mapping->i_mmap))
543 			hugetlb_vmdelete_list(&mapping->i_mmap,
544 						hole_start >> PAGE_SHIFT,
545 						hole_end  >> PAGE_SHIFT);
546 		i_mmap_unlock_write(mapping);
547 		remove_inode_hugepages(inode, hole_start, hole_end);
548 		inode_unlock(inode);
549 	}
550 
551 	return 0;
552 }
553 
554 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
555 				loff_t len)
556 {
557 	struct inode *inode = file_inode(file);
558 	struct address_space *mapping = inode->i_mapping;
559 	struct hstate *h = hstate_inode(inode);
560 	struct vm_area_struct pseudo_vma;
561 	struct mm_struct *mm = current->mm;
562 	loff_t hpage_size = huge_page_size(h);
563 	unsigned long hpage_shift = huge_page_shift(h);
564 	pgoff_t start, index, end;
565 	int error;
566 	u32 hash;
567 
568 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
569 		return -EOPNOTSUPP;
570 
571 	if (mode & FALLOC_FL_PUNCH_HOLE)
572 		return hugetlbfs_punch_hole(inode, offset, len);
573 
574 	/*
575 	 * Default preallocate case.
576 	 * For this range, start is rounded down and end is rounded up
577 	 * as well as being converted to page offsets.
578 	 */
579 	start = offset >> hpage_shift;
580 	end = (offset + len + hpage_size - 1) >> hpage_shift;
581 
582 	inode_lock(inode);
583 
584 	/* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
585 	error = inode_newsize_ok(inode, offset + len);
586 	if (error)
587 		goto out;
588 
589 	/*
590 	 * Initialize a pseudo vma as this is required by the huge page
591 	 * allocation routines.  If NUMA is configured, use page index
592 	 * as input to create an allocation policy.
593 	 */
594 	memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
595 	pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
596 	pseudo_vma.vm_file = file;
597 
598 	for (index = start; index < end; index++) {
599 		/*
600 		 * This is supposed to be the vaddr where the page is being
601 		 * faulted in, but we have no vaddr here.
602 		 */
603 		struct page *page;
604 		unsigned long addr;
605 		int avoid_reserve = 0;
606 
607 		cond_resched();
608 
609 		/*
610 		 * fallocate(2) manpage permits EINTR; we may have been
611 		 * interrupted because we are using up too much memory.
612 		 */
613 		if (signal_pending(current)) {
614 			error = -EINTR;
615 			break;
616 		}
617 
618 		/* Set numa allocation policy based on index */
619 		hugetlb_set_vma_policy(&pseudo_vma, inode, index);
620 
621 		/* addr is the offset within the file (zero based) */
622 		addr = index * hpage_size;
623 
624 		/* mutex taken here, fault path and hole punch */
625 		hash = hugetlb_fault_mutex_hash(h, mm, &pseudo_vma, mapping,
626 						index, addr);
627 		mutex_lock(&hugetlb_fault_mutex_table[hash]);
628 
629 		/* See if already present in mapping to avoid alloc/free */
630 		page = find_get_page(mapping, index);
631 		if (page) {
632 			put_page(page);
633 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
634 			hugetlb_drop_vma_policy(&pseudo_vma);
635 			continue;
636 		}
637 
638 		/* Allocate page and add to page cache */
639 		page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
640 		hugetlb_drop_vma_policy(&pseudo_vma);
641 		if (IS_ERR(page)) {
642 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
643 			error = PTR_ERR(page);
644 			goto out;
645 		}
646 		clear_huge_page(page, addr, pages_per_huge_page(h));
647 		__SetPageUptodate(page);
648 		error = huge_add_to_page_cache(page, mapping, index);
649 		if (unlikely(error)) {
650 			put_page(page);
651 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
652 			goto out;
653 		}
654 
655 		mutex_unlock(&hugetlb_fault_mutex_table[hash]);
656 
657 		/*
658 		 * page_put due to reference from alloc_huge_page()
659 		 * unlock_page because locked by add_to_page_cache()
660 		 */
661 		put_page(page);
662 		unlock_page(page);
663 	}
664 
665 	if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
666 		i_size_write(inode, offset + len);
667 	inode->i_ctime = current_time(inode);
668 out:
669 	inode_unlock(inode);
670 	return error;
671 }
672 
673 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
674 {
675 	struct inode *inode = d_inode(dentry);
676 	struct hstate *h = hstate_inode(inode);
677 	int error;
678 	unsigned int ia_valid = attr->ia_valid;
679 
680 	BUG_ON(!inode);
681 
682 	error = setattr_prepare(dentry, attr);
683 	if (error)
684 		return error;
685 
686 	if (ia_valid & ATTR_SIZE) {
687 		error = -EINVAL;
688 		if (attr->ia_size & ~huge_page_mask(h))
689 			return -EINVAL;
690 		error = hugetlb_vmtruncate(inode, attr->ia_size);
691 		if (error)
692 			return error;
693 	}
694 
695 	setattr_copy(inode, attr);
696 	mark_inode_dirty(inode);
697 	return 0;
698 }
699 
700 static struct inode *hugetlbfs_get_root(struct super_block *sb,
701 					struct hugetlbfs_config *config)
702 {
703 	struct inode *inode;
704 
705 	inode = new_inode(sb);
706 	if (inode) {
707 		inode->i_ino = get_next_ino();
708 		inode->i_mode = S_IFDIR | config->mode;
709 		inode->i_uid = config->uid;
710 		inode->i_gid = config->gid;
711 		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
712 		inode->i_op = &hugetlbfs_dir_inode_operations;
713 		inode->i_fop = &simple_dir_operations;
714 		/* directory inodes start off with i_nlink == 2 (for "." entry) */
715 		inc_nlink(inode);
716 		lockdep_annotate_inode_mutex_key(inode);
717 	}
718 	return inode;
719 }
720 
721 /*
722  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
723  * be taken from reclaim -- unlike regular filesystems. This needs an
724  * annotation because huge_pmd_share() does an allocation under hugetlb's
725  * i_mmap_rwsem.
726  */
727 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
728 
729 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
730 					struct inode *dir,
731 					umode_t mode, dev_t dev)
732 {
733 	struct inode *inode;
734 	struct resv_map *resv_map;
735 
736 	resv_map = resv_map_alloc();
737 	if (!resv_map)
738 		return NULL;
739 
740 	inode = new_inode(sb);
741 	if (inode) {
742 		inode->i_ino = get_next_ino();
743 		inode_init_owner(inode, dir, mode);
744 		lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
745 				&hugetlbfs_i_mmap_rwsem_key);
746 		inode->i_mapping->a_ops = &hugetlbfs_aops;
747 		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
748 		inode->i_mapping->private_data = resv_map;
749 		switch (mode & S_IFMT) {
750 		default:
751 			init_special_inode(inode, mode, dev);
752 			break;
753 		case S_IFREG:
754 			inode->i_op = &hugetlbfs_inode_operations;
755 			inode->i_fop = &hugetlbfs_file_operations;
756 			break;
757 		case S_IFDIR:
758 			inode->i_op = &hugetlbfs_dir_inode_operations;
759 			inode->i_fop = &simple_dir_operations;
760 
761 			/* directory inodes start off with i_nlink == 2 (for "." entry) */
762 			inc_nlink(inode);
763 			break;
764 		case S_IFLNK:
765 			inode->i_op = &page_symlink_inode_operations;
766 			inode_nohighmem(inode);
767 			break;
768 		}
769 		lockdep_annotate_inode_mutex_key(inode);
770 	} else
771 		kref_put(&resv_map->refs, resv_map_release);
772 
773 	return inode;
774 }
775 
776 /*
777  * File creation. Allocate an inode, and we're done..
778  */
779 static int hugetlbfs_mknod(struct inode *dir,
780 			struct dentry *dentry, umode_t mode, dev_t dev)
781 {
782 	struct inode *inode;
783 	int error = -ENOSPC;
784 
785 	inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
786 	if (inode) {
787 		dir->i_ctime = dir->i_mtime = current_time(dir);
788 		d_instantiate(dentry, inode);
789 		dget(dentry);	/* Extra count - pin the dentry in core */
790 		error = 0;
791 	}
792 	return error;
793 }
794 
795 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
796 {
797 	int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
798 	if (!retval)
799 		inc_nlink(dir);
800 	return retval;
801 }
802 
803 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
804 {
805 	return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
806 }
807 
808 static int hugetlbfs_symlink(struct inode *dir,
809 			struct dentry *dentry, const char *symname)
810 {
811 	struct inode *inode;
812 	int error = -ENOSPC;
813 
814 	inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
815 	if (inode) {
816 		int l = strlen(symname)+1;
817 		error = page_symlink(inode, symname, l);
818 		if (!error) {
819 			d_instantiate(dentry, inode);
820 			dget(dentry);
821 		} else
822 			iput(inode);
823 	}
824 	dir->i_ctime = dir->i_mtime = current_time(dir);
825 
826 	return error;
827 }
828 
829 /*
830  * mark the head page dirty
831  */
832 static int hugetlbfs_set_page_dirty(struct page *page)
833 {
834 	struct page *head = compound_head(page);
835 
836 	SetPageDirty(head);
837 	return 0;
838 }
839 
840 static int hugetlbfs_migrate_page(struct address_space *mapping,
841 				struct page *newpage, struct page *page,
842 				enum migrate_mode mode)
843 {
844 	int rc;
845 
846 	rc = migrate_huge_page_move_mapping(mapping, newpage, page);
847 	if (rc != MIGRATEPAGE_SUCCESS)
848 		return rc;
849 	migrate_page_copy(newpage, page);
850 
851 	return MIGRATEPAGE_SUCCESS;
852 }
853 
854 static int hugetlbfs_error_remove_page(struct address_space *mapping,
855 				struct page *page)
856 {
857 	struct inode *inode = mapping->host;
858 
859 	remove_huge_page(page);
860 	hugetlb_fix_reserve_counts(inode);
861 	return 0;
862 }
863 
864 /*
865  * Display the mount options in /proc/mounts.
866  */
867 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
868 {
869 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
870 	struct hugepage_subpool *spool = sbinfo->spool;
871 	unsigned long hpage_size = huge_page_size(sbinfo->hstate);
872 	unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
873 	char mod;
874 
875 	if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
876 		seq_printf(m, ",uid=%u",
877 			   from_kuid_munged(&init_user_ns, sbinfo->uid));
878 	if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
879 		seq_printf(m, ",gid=%u",
880 			   from_kgid_munged(&init_user_ns, sbinfo->gid));
881 	if (sbinfo->mode != 0755)
882 		seq_printf(m, ",mode=%o", sbinfo->mode);
883 	if (sbinfo->max_inodes != -1)
884 		seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
885 
886 	hpage_size /= 1024;
887 	mod = 'K';
888 	if (hpage_size >= 1024) {
889 		hpage_size /= 1024;
890 		mod = 'M';
891 	}
892 	seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
893 	if (spool) {
894 		if (spool->max_hpages != -1)
895 			seq_printf(m, ",size=%llu",
896 				   (unsigned long long)spool->max_hpages << hpage_shift);
897 		if (spool->min_hpages != -1)
898 			seq_printf(m, ",min_size=%llu",
899 				   (unsigned long long)spool->min_hpages << hpage_shift);
900 	}
901 	return 0;
902 }
903 
904 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
905 {
906 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
907 	struct hstate *h = hstate_inode(d_inode(dentry));
908 
909 	buf->f_type = HUGETLBFS_MAGIC;
910 	buf->f_bsize = huge_page_size(h);
911 	if (sbinfo) {
912 		spin_lock(&sbinfo->stat_lock);
913 		/* If no limits set, just report 0 for max/free/used
914 		 * blocks, like simple_statfs() */
915 		if (sbinfo->spool) {
916 			long free_pages;
917 
918 			spin_lock(&sbinfo->spool->lock);
919 			buf->f_blocks = sbinfo->spool->max_hpages;
920 			free_pages = sbinfo->spool->max_hpages
921 				- sbinfo->spool->used_hpages;
922 			buf->f_bavail = buf->f_bfree = free_pages;
923 			spin_unlock(&sbinfo->spool->lock);
924 			buf->f_files = sbinfo->max_inodes;
925 			buf->f_ffree = sbinfo->free_inodes;
926 		}
927 		spin_unlock(&sbinfo->stat_lock);
928 	}
929 	buf->f_namelen = NAME_MAX;
930 	return 0;
931 }
932 
933 static void hugetlbfs_put_super(struct super_block *sb)
934 {
935 	struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
936 
937 	if (sbi) {
938 		sb->s_fs_info = NULL;
939 
940 		if (sbi->spool)
941 			hugepage_put_subpool(sbi->spool);
942 
943 		kfree(sbi);
944 	}
945 }
946 
947 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
948 {
949 	if (sbinfo->free_inodes >= 0) {
950 		spin_lock(&sbinfo->stat_lock);
951 		if (unlikely(!sbinfo->free_inodes)) {
952 			spin_unlock(&sbinfo->stat_lock);
953 			return 0;
954 		}
955 		sbinfo->free_inodes--;
956 		spin_unlock(&sbinfo->stat_lock);
957 	}
958 
959 	return 1;
960 }
961 
962 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
963 {
964 	if (sbinfo->free_inodes >= 0) {
965 		spin_lock(&sbinfo->stat_lock);
966 		sbinfo->free_inodes++;
967 		spin_unlock(&sbinfo->stat_lock);
968 	}
969 }
970 
971 
972 static struct kmem_cache *hugetlbfs_inode_cachep;
973 
974 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
975 {
976 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
977 	struct hugetlbfs_inode_info *p;
978 
979 	if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
980 		return NULL;
981 	p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
982 	if (unlikely(!p)) {
983 		hugetlbfs_inc_free_inodes(sbinfo);
984 		return NULL;
985 	}
986 
987 	/*
988 	 * Any time after allocation, hugetlbfs_destroy_inode can be called
989 	 * for the inode.  mpol_free_shared_policy is unconditionally called
990 	 * as part of hugetlbfs_destroy_inode.  So, initialize policy here
991 	 * in case of a quick call to destroy.
992 	 *
993 	 * Note that the policy is initialized even if we are creating a
994 	 * private inode.  This simplifies hugetlbfs_destroy_inode.
995 	 */
996 	mpol_shared_policy_init(&p->policy, NULL);
997 
998 	return &p->vfs_inode;
999 }
1000 
1001 static void hugetlbfs_i_callback(struct rcu_head *head)
1002 {
1003 	struct inode *inode = container_of(head, struct inode, i_rcu);
1004 	kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1005 }
1006 
1007 static void hugetlbfs_destroy_inode(struct inode *inode)
1008 {
1009 	hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1010 	mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1011 	call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
1012 }
1013 
1014 static const struct address_space_operations hugetlbfs_aops = {
1015 	.write_begin	= hugetlbfs_write_begin,
1016 	.write_end	= hugetlbfs_write_end,
1017 	.set_page_dirty	= hugetlbfs_set_page_dirty,
1018 	.migratepage    = hugetlbfs_migrate_page,
1019 	.error_remove_page	= hugetlbfs_error_remove_page,
1020 };
1021 
1022 
1023 static void init_once(void *foo)
1024 {
1025 	struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1026 
1027 	inode_init_once(&ei->vfs_inode);
1028 }
1029 
1030 const struct file_operations hugetlbfs_file_operations = {
1031 	.read_iter		= hugetlbfs_read_iter,
1032 	.mmap			= hugetlbfs_file_mmap,
1033 	.fsync			= noop_fsync,
1034 	.get_unmapped_area	= hugetlb_get_unmapped_area,
1035 	.llseek			= default_llseek,
1036 	.fallocate		= hugetlbfs_fallocate,
1037 };
1038 
1039 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1040 	.create		= hugetlbfs_create,
1041 	.lookup		= simple_lookup,
1042 	.link		= simple_link,
1043 	.unlink		= simple_unlink,
1044 	.symlink	= hugetlbfs_symlink,
1045 	.mkdir		= hugetlbfs_mkdir,
1046 	.rmdir		= simple_rmdir,
1047 	.mknod		= hugetlbfs_mknod,
1048 	.rename		= simple_rename,
1049 	.setattr	= hugetlbfs_setattr,
1050 };
1051 
1052 static const struct inode_operations hugetlbfs_inode_operations = {
1053 	.setattr	= hugetlbfs_setattr,
1054 };
1055 
1056 static const struct super_operations hugetlbfs_ops = {
1057 	.alloc_inode    = hugetlbfs_alloc_inode,
1058 	.destroy_inode  = hugetlbfs_destroy_inode,
1059 	.evict_inode	= hugetlbfs_evict_inode,
1060 	.statfs		= hugetlbfs_statfs,
1061 	.put_super	= hugetlbfs_put_super,
1062 	.show_options	= hugetlbfs_show_options,
1063 };
1064 
1065 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
1066 
1067 /*
1068  * Convert size option passed from command line to number of huge pages
1069  * in the pool specified by hstate.  Size option could be in bytes
1070  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1071  */
1072 static long
1073 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1074 			 enum hugetlbfs_size_type val_type)
1075 {
1076 	if (val_type == NO_SIZE)
1077 		return -1;
1078 
1079 	if (val_type == SIZE_PERCENT) {
1080 		size_opt <<= huge_page_shift(h);
1081 		size_opt *= h->max_huge_pages;
1082 		do_div(size_opt, 100);
1083 	}
1084 
1085 	size_opt >>= huge_page_shift(h);
1086 	return size_opt;
1087 }
1088 
1089 static int
1090 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
1091 {
1092 	char *p, *rest;
1093 	substring_t args[MAX_OPT_ARGS];
1094 	int option;
1095 	unsigned long long max_size_opt = 0, min_size_opt = 0;
1096 	enum hugetlbfs_size_type max_val_type = NO_SIZE, min_val_type = NO_SIZE;
1097 
1098 	if (!options)
1099 		return 0;
1100 
1101 	while ((p = strsep(&options, ",")) != NULL) {
1102 		int token;
1103 		if (!*p)
1104 			continue;
1105 
1106 		token = match_token(p, tokens, args);
1107 		switch (token) {
1108 		case Opt_uid:
1109 			if (match_int(&args[0], &option))
1110  				goto bad_val;
1111 			pconfig->uid = make_kuid(current_user_ns(), option);
1112 			if (!uid_valid(pconfig->uid))
1113 				goto bad_val;
1114 			break;
1115 
1116 		case Opt_gid:
1117 			if (match_int(&args[0], &option))
1118  				goto bad_val;
1119 			pconfig->gid = make_kgid(current_user_ns(), option);
1120 			if (!gid_valid(pconfig->gid))
1121 				goto bad_val;
1122 			break;
1123 
1124 		case Opt_mode:
1125 			if (match_octal(&args[0], &option))
1126  				goto bad_val;
1127 			pconfig->mode = option & 01777U;
1128 			break;
1129 
1130 		case Opt_size: {
1131 			/* memparse() will accept a K/M/G without a digit */
1132 			if (!isdigit(*args[0].from))
1133 				goto bad_val;
1134 			max_size_opt = memparse(args[0].from, &rest);
1135 			max_val_type = SIZE_STD;
1136 			if (*rest == '%')
1137 				max_val_type = SIZE_PERCENT;
1138 			break;
1139 		}
1140 
1141 		case Opt_nr_inodes:
1142 			/* memparse() will accept a K/M/G without a digit */
1143 			if (!isdigit(*args[0].from))
1144 				goto bad_val;
1145 			pconfig->nr_inodes = memparse(args[0].from, &rest);
1146 			break;
1147 
1148 		case Opt_pagesize: {
1149 			unsigned long ps;
1150 			ps = memparse(args[0].from, &rest);
1151 			pconfig->hstate = size_to_hstate(ps);
1152 			if (!pconfig->hstate) {
1153 				pr_err("Unsupported page size %lu MB\n",
1154 					ps >> 20);
1155 				return -EINVAL;
1156 			}
1157 			break;
1158 		}
1159 
1160 		case Opt_min_size: {
1161 			/* memparse() will accept a K/M/G without a digit */
1162 			if (!isdigit(*args[0].from))
1163 				goto bad_val;
1164 			min_size_opt = memparse(args[0].from, &rest);
1165 			min_val_type = SIZE_STD;
1166 			if (*rest == '%')
1167 				min_val_type = SIZE_PERCENT;
1168 			break;
1169 		}
1170 
1171 		default:
1172 			pr_err("Bad mount option: \"%s\"\n", p);
1173 			return -EINVAL;
1174 			break;
1175 		}
1176 	}
1177 
1178 	/*
1179 	 * Use huge page pool size (in hstate) to convert the size
1180 	 * options to number of huge pages.  If NO_SIZE, -1 is returned.
1181 	 */
1182 	pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1183 						max_size_opt, max_val_type);
1184 	pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1185 						min_size_opt, min_val_type);
1186 
1187 	/*
1188 	 * If max_size was specified, then min_size must be smaller
1189 	 */
1190 	if (max_val_type > NO_SIZE &&
1191 	    pconfig->min_hpages > pconfig->max_hpages) {
1192 		pr_err("minimum size can not be greater than maximum size\n");
1193 		return -EINVAL;
1194 	}
1195 
1196 	return 0;
1197 
1198 bad_val:
1199 	pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
1200  	return -EINVAL;
1201 }
1202 
1203 static int
1204 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
1205 {
1206 	int ret;
1207 	struct hugetlbfs_config config;
1208 	struct hugetlbfs_sb_info *sbinfo;
1209 
1210 	config.max_hpages = -1; /* No limit on size by default */
1211 	config.nr_inodes = -1; /* No limit on number of inodes by default */
1212 	config.uid = current_fsuid();
1213 	config.gid = current_fsgid();
1214 	config.mode = 0755;
1215 	config.hstate = &default_hstate;
1216 	config.min_hpages = -1; /* No default minimum size */
1217 	ret = hugetlbfs_parse_options(data, &config);
1218 	if (ret)
1219 		return ret;
1220 
1221 	sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1222 	if (!sbinfo)
1223 		return -ENOMEM;
1224 	sb->s_fs_info = sbinfo;
1225 	sbinfo->hstate = config.hstate;
1226 	spin_lock_init(&sbinfo->stat_lock);
1227 	sbinfo->max_inodes = config.nr_inodes;
1228 	sbinfo->free_inodes = config.nr_inodes;
1229 	sbinfo->spool = NULL;
1230 	sbinfo->uid = config.uid;
1231 	sbinfo->gid = config.gid;
1232 	sbinfo->mode = config.mode;
1233 
1234 	/*
1235 	 * Allocate and initialize subpool if maximum or minimum size is
1236 	 * specified.  Any needed reservations (for minimim size) are taken
1237 	 * taken when the subpool is created.
1238 	 */
1239 	if (config.max_hpages != -1 || config.min_hpages != -1) {
1240 		sbinfo->spool = hugepage_new_subpool(config.hstate,
1241 							config.max_hpages,
1242 							config.min_hpages);
1243 		if (!sbinfo->spool)
1244 			goto out_free;
1245 	}
1246 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1247 	sb->s_blocksize = huge_page_size(config.hstate);
1248 	sb->s_blocksize_bits = huge_page_shift(config.hstate);
1249 	sb->s_magic = HUGETLBFS_MAGIC;
1250 	sb->s_op = &hugetlbfs_ops;
1251 	sb->s_time_gran = 1;
1252 	sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
1253 	if (!sb->s_root)
1254 		goto out_free;
1255 	return 0;
1256 out_free:
1257 	kfree(sbinfo->spool);
1258 	kfree(sbinfo);
1259 	return -ENOMEM;
1260 }
1261 
1262 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
1263 	int flags, const char *dev_name, void *data)
1264 {
1265 	return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
1266 }
1267 
1268 static struct file_system_type hugetlbfs_fs_type = {
1269 	.name		= "hugetlbfs",
1270 	.mount		= hugetlbfs_mount,
1271 	.kill_sb	= kill_litter_super,
1272 };
1273 
1274 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1275 
1276 static int can_do_hugetlb_shm(void)
1277 {
1278 	kgid_t shm_group;
1279 	shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1280 	return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1281 }
1282 
1283 static int get_hstate_idx(int page_size_log)
1284 {
1285 	struct hstate *h = hstate_sizelog(page_size_log);
1286 
1287 	if (!h)
1288 		return -1;
1289 	return h - hstates;
1290 }
1291 
1292 static const struct dentry_operations anon_ops = {
1293 	.d_dname = simple_dname
1294 };
1295 
1296 /*
1297  * Note that size should be aligned to proper hugepage size in caller side,
1298  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1299  */
1300 struct file *hugetlb_file_setup(const char *name, size_t size,
1301 				vm_flags_t acctflag, struct user_struct **user,
1302 				int creat_flags, int page_size_log)
1303 {
1304 	struct file *file = ERR_PTR(-ENOMEM);
1305 	struct inode *inode;
1306 	struct path path;
1307 	struct super_block *sb;
1308 	struct qstr quick_string;
1309 	int hstate_idx;
1310 
1311 	hstate_idx = get_hstate_idx(page_size_log);
1312 	if (hstate_idx < 0)
1313 		return ERR_PTR(-ENODEV);
1314 
1315 	*user = NULL;
1316 	if (!hugetlbfs_vfsmount[hstate_idx])
1317 		return ERR_PTR(-ENOENT);
1318 
1319 	if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1320 		*user = current_user();
1321 		if (user_shm_lock(size, *user)) {
1322 			task_lock(current);
1323 			pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1324 				current->comm, current->pid);
1325 			task_unlock(current);
1326 		} else {
1327 			*user = NULL;
1328 			return ERR_PTR(-EPERM);
1329 		}
1330 	}
1331 
1332 	sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
1333 	quick_string.name = name;
1334 	quick_string.len = strlen(quick_string.name);
1335 	quick_string.hash = 0;
1336 	path.dentry = d_alloc_pseudo(sb, &quick_string);
1337 	if (!path.dentry)
1338 		goto out_shm_unlock;
1339 
1340 	d_set_d_op(path.dentry, &anon_ops);
1341 	path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
1342 	file = ERR_PTR(-ENOSPC);
1343 	inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
1344 	if (!inode)
1345 		goto out_dentry;
1346 	if (creat_flags == HUGETLB_SHMFS_INODE)
1347 		inode->i_flags |= S_PRIVATE;
1348 
1349 	file = ERR_PTR(-ENOMEM);
1350 	if (hugetlb_reserve_pages(inode, 0,
1351 			size >> huge_page_shift(hstate_inode(inode)), NULL,
1352 			acctflag))
1353 		goto out_inode;
1354 
1355 	d_instantiate(path.dentry, inode);
1356 	inode->i_size = size;
1357 	clear_nlink(inode);
1358 
1359 	file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1360 			&hugetlbfs_file_operations);
1361 	if (IS_ERR(file))
1362 		goto out_dentry; /* inode is already attached */
1363 
1364 	return file;
1365 
1366 out_inode:
1367 	iput(inode);
1368 out_dentry:
1369 	path_put(&path);
1370 out_shm_unlock:
1371 	if (*user) {
1372 		user_shm_unlock(size, *user);
1373 		*user = NULL;
1374 	}
1375 	return file;
1376 }
1377 
1378 static int __init init_hugetlbfs_fs(void)
1379 {
1380 	struct hstate *h;
1381 	int error;
1382 	int i;
1383 
1384 	if (!hugepages_supported()) {
1385 		pr_info("disabling because there are no supported hugepage sizes\n");
1386 		return -ENOTSUPP;
1387 	}
1388 
1389 	error = -ENOMEM;
1390 	hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1391 					sizeof(struct hugetlbfs_inode_info),
1392 					0, SLAB_ACCOUNT, init_once);
1393 	if (hugetlbfs_inode_cachep == NULL)
1394 		goto out2;
1395 
1396 	error = register_filesystem(&hugetlbfs_fs_type);
1397 	if (error)
1398 		goto out;
1399 
1400 	i = 0;
1401 	for_each_hstate(h) {
1402 		char buf[50];
1403 		unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1404 
1405 		snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1406 		hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1407 							buf);
1408 
1409 		if (IS_ERR(hugetlbfs_vfsmount[i])) {
1410 			pr_err("Cannot mount internal hugetlbfs for "
1411 				"page size %uK", ps_kb);
1412 			error = PTR_ERR(hugetlbfs_vfsmount[i]);
1413 			hugetlbfs_vfsmount[i] = NULL;
1414 		}
1415 		i++;
1416 	}
1417 	/* Non default hstates are optional */
1418 	if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1419 		return 0;
1420 
1421  out:
1422 	kmem_cache_destroy(hugetlbfs_inode_cachep);
1423  out2:
1424 	return error;
1425 }
1426 fs_initcall(init_hugetlbfs_fs)
1427