xref: /openbmc/linux/fs/hugetlbfs/inode.c (revision e8e0929d)
1 /*
2  * hugetlbpage-backed filesystem.  Based on ramfs.
3  *
4  * William Irwin, 2002
5  *
6  * Copyright (C) 2002 Linus Torvalds.
7  */
8 
9 #include <linux/module.h>
10 #include <linux/thread_info.h>
11 #include <asm/current.h>
12 #include <linux/sched.h>		/* remove ASAP */
13 #include <linux/fs.h>
14 #include <linux/mount.h>
15 #include <linux/file.h>
16 #include <linux/kernel.h>
17 #include <linux/writeback.h>
18 #include <linux/pagemap.h>
19 #include <linux/highmem.h>
20 #include <linux/init.h>
21 #include <linux/string.h>
22 #include <linux/capability.h>
23 #include <linux/ctype.h>
24 #include <linux/backing-dev.h>
25 #include <linux/hugetlb.h>
26 #include <linux/pagevec.h>
27 #include <linux/parser.h>
28 #include <linux/mman.h>
29 #include <linux/slab.h>
30 #include <linux/dnotify.h>
31 #include <linux/statfs.h>
32 #include <linux/security.h>
33 #include <linux/ima.h>
34 #include <linux/magic.h>
35 
36 #include <asm/uaccess.h>
37 
38 static const struct super_operations hugetlbfs_ops;
39 static const struct address_space_operations hugetlbfs_aops;
40 const struct file_operations hugetlbfs_file_operations;
41 static const struct inode_operations hugetlbfs_dir_inode_operations;
42 static const struct inode_operations hugetlbfs_inode_operations;
43 
44 static struct backing_dev_info hugetlbfs_backing_dev_info = {
45 	.name		= "hugetlbfs",
46 	.ra_pages	= 0,	/* No readahead */
47 	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
48 };
49 
50 int sysctl_hugetlb_shm_group;
51 
52 enum {
53 	Opt_size, Opt_nr_inodes,
54 	Opt_mode, Opt_uid, Opt_gid,
55 	Opt_pagesize,
56 	Opt_err,
57 };
58 
59 static const match_table_t tokens = {
60 	{Opt_size,	"size=%s"},
61 	{Opt_nr_inodes,	"nr_inodes=%s"},
62 	{Opt_mode,	"mode=%o"},
63 	{Opt_uid,	"uid=%u"},
64 	{Opt_gid,	"gid=%u"},
65 	{Opt_pagesize,	"pagesize=%s"},
66 	{Opt_err,	NULL},
67 };
68 
69 static void huge_pagevec_release(struct pagevec *pvec)
70 {
71 	int i;
72 
73 	for (i = 0; i < pagevec_count(pvec); ++i)
74 		put_page(pvec->pages[i]);
75 
76 	pagevec_reinit(pvec);
77 }
78 
79 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
80 {
81 	struct inode *inode = file->f_path.dentry->d_inode;
82 	loff_t len, vma_len;
83 	int ret;
84 	struct hstate *h = hstate_file(file);
85 
86 	/*
87 	 * vma address alignment (but not the pgoff alignment) has
88 	 * already been checked by prepare_hugepage_range.  If you add
89 	 * any error returns here, do so after setting VM_HUGETLB, so
90 	 * is_vm_hugetlb_page tests below unmap_region go the right
91 	 * way when do_mmap_pgoff unwinds (may be important on powerpc
92 	 * and ia64).
93 	 */
94 	vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
95 	vma->vm_ops = &hugetlb_vm_ops;
96 
97 	if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
98 		return -EINVAL;
99 
100 	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
101 
102 	mutex_lock(&inode->i_mutex);
103 	file_accessed(file);
104 
105 	ret = -ENOMEM;
106 	len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
107 
108 	if (hugetlb_reserve_pages(inode,
109 				vma->vm_pgoff >> huge_page_order(h),
110 				len >> huge_page_shift(h), vma,
111 				vma->vm_flags))
112 		goto out;
113 
114 	ret = 0;
115 	hugetlb_prefault_arch_hook(vma->vm_mm);
116 	if (vma->vm_flags & VM_WRITE && inode->i_size < len)
117 		inode->i_size = len;
118 out:
119 	mutex_unlock(&inode->i_mutex);
120 
121 	return ret;
122 }
123 
124 /*
125  * Called under down_write(mmap_sem).
126  */
127 
128 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
129 static unsigned long
130 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
131 		unsigned long len, unsigned long pgoff, unsigned long flags)
132 {
133 	struct mm_struct *mm = current->mm;
134 	struct vm_area_struct *vma;
135 	unsigned long start_addr;
136 	struct hstate *h = hstate_file(file);
137 
138 	if (len & ~huge_page_mask(h))
139 		return -EINVAL;
140 	if (len > TASK_SIZE)
141 		return -ENOMEM;
142 
143 	if (flags & MAP_FIXED) {
144 		if (prepare_hugepage_range(file, addr, len))
145 			return -EINVAL;
146 		return addr;
147 	}
148 
149 	if (addr) {
150 		addr = ALIGN(addr, huge_page_size(h));
151 		vma = find_vma(mm, addr);
152 		if (TASK_SIZE - len >= addr &&
153 		    (!vma || addr + len <= vma->vm_start))
154 			return addr;
155 	}
156 
157 	start_addr = mm->free_area_cache;
158 
159 	if (len <= mm->cached_hole_size)
160 		start_addr = TASK_UNMAPPED_BASE;
161 
162 full_search:
163 	addr = ALIGN(start_addr, huge_page_size(h));
164 
165 	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
166 		/* At this point:  (!vma || addr < vma->vm_end). */
167 		if (TASK_SIZE - len < addr) {
168 			/*
169 			 * Start a new search - just in case we missed
170 			 * some holes.
171 			 */
172 			if (start_addr != TASK_UNMAPPED_BASE) {
173 				start_addr = TASK_UNMAPPED_BASE;
174 				goto full_search;
175 			}
176 			return -ENOMEM;
177 		}
178 
179 		if (!vma || addr + len <= vma->vm_start)
180 			return addr;
181 		addr = ALIGN(vma->vm_end, huge_page_size(h));
182 	}
183 }
184 #endif
185 
186 static int
187 hugetlbfs_read_actor(struct page *page, unsigned long offset,
188 			char __user *buf, unsigned long count,
189 			unsigned long size)
190 {
191 	char *kaddr;
192 	unsigned long left, copied = 0;
193 	int i, chunksize;
194 
195 	if (size > count)
196 		size = count;
197 
198 	/* Find which 4k chunk and offset with in that chunk */
199 	i = offset >> PAGE_CACHE_SHIFT;
200 	offset = offset & ~PAGE_CACHE_MASK;
201 
202 	while (size) {
203 		chunksize = PAGE_CACHE_SIZE;
204 		if (offset)
205 			chunksize -= offset;
206 		if (chunksize > size)
207 			chunksize = size;
208 		kaddr = kmap(&page[i]);
209 		left = __copy_to_user(buf, kaddr + offset, chunksize);
210 		kunmap(&page[i]);
211 		if (left) {
212 			copied += (chunksize - left);
213 			break;
214 		}
215 		offset = 0;
216 		size -= chunksize;
217 		buf += chunksize;
218 		copied += chunksize;
219 		i++;
220 	}
221 	return copied ? copied : -EFAULT;
222 }
223 
224 /*
225  * Support for read() - Find the page attached to f_mapping and copy out the
226  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
227  * since it has PAGE_CACHE_SIZE assumptions.
228  */
229 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
230 			      size_t len, loff_t *ppos)
231 {
232 	struct hstate *h = hstate_file(filp);
233 	struct address_space *mapping = filp->f_mapping;
234 	struct inode *inode = mapping->host;
235 	unsigned long index = *ppos >> huge_page_shift(h);
236 	unsigned long offset = *ppos & ~huge_page_mask(h);
237 	unsigned long end_index;
238 	loff_t isize;
239 	ssize_t retval = 0;
240 
241 	mutex_lock(&inode->i_mutex);
242 
243 	/* validate length */
244 	if (len == 0)
245 		goto out;
246 
247 	isize = i_size_read(inode);
248 	if (!isize)
249 		goto out;
250 
251 	end_index = (isize - 1) >> huge_page_shift(h);
252 	for (;;) {
253 		struct page *page;
254 		unsigned long nr, ret;
255 		int ra;
256 
257 		/* nr is the maximum number of bytes to copy from this page */
258 		nr = huge_page_size(h);
259 		if (index >= end_index) {
260 			if (index > end_index)
261 				goto out;
262 			nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
263 			if (nr <= offset) {
264 				goto out;
265 			}
266 		}
267 		nr = nr - offset;
268 
269 		/* Find the page */
270 		page = find_get_page(mapping, index);
271 		if (unlikely(page == NULL)) {
272 			/*
273 			 * We have a HOLE, zero out the user-buffer for the
274 			 * length of the hole or request.
275 			 */
276 			ret = len < nr ? len : nr;
277 			if (clear_user(buf, ret))
278 				ra = -EFAULT;
279 			else
280 				ra = 0;
281 		} else {
282 			/*
283 			 * We have the page, copy it to user space buffer.
284 			 */
285 			ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
286 			ret = ra;
287 		}
288 		if (ra < 0) {
289 			if (retval == 0)
290 				retval = ra;
291 			if (page)
292 				page_cache_release(page);
293 			goto out;
294 		}
295 
296 		offset += ret;
297 		retval += ret;
298 		len -= ret;
299 		index += offset >> huge_page_shift(h);
300 		offset &= ~huge_page_mask(h);
301 
302 		if (page)
303 			page_cache_release(page);
304 
305 		/* short read or no more work */
306 		if ((ret != nr) || (len == 0))
307 			break;
308 	}
309 out:
310 	*ppos = ((loff_t)index << huge_page_shift(h)) + offset;
311 	mutex_unlock(&inode->i_mutex);
312 	return retval;
313 }
314 
315 static int hugetlbfs_write_begin(struct file *file,
316 			struct address_space *mapping,
317 			loff_t pos, unsigned len, unsigned flags,
318 			struct page **pagep, void **fsdata)
319 {
320 	return -EINVAL;
321 }
322 
323 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
324 			loff_t pos, unsigned len, unsigned copied,
325 			struct page *page, void *fsdata)
326 {
327 	BUG();
328 	return -EINVAL;
329 }
330 
331 static void truncate_huge_page(struct page *page)
332 {
333 	cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
334 	ClearPageUptodate(page);
335 	remove_from_page_cache(page);
336 	put_page(page);
337 }
338 
339 static void truncate_hugepages(struct inode *inode, loff_t lstart)
340 {
341 	struct hstate *h = hstate_inode(inode);
342 	struct address_space *mapping = &inode->i_data;
343 	const pgoff_t start = lstart >> huge_page_shift(h);
344 	struct pagevec pvec;
345 	pgoff_t next;
346 	int i, freed = 0;
347 
348 	pagevec_init(&pvec, 0);
349 	next = start;
350 	while (1) {
351 		if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
352 			if (next == start)
353 				break;
354 			next = start;
355 			continue;
356 		}
357 
358 		for (i = 0; i < pagevec_count(&pvec); ++i) {
359 			struct page *page = pvec.pages[i];
360 
361 			lock_page(page);
362 			if (page->index > next)
363 				next = page->index;
364 			++next;
365 			truncate_huge_page(page);
366 			unlock_page(page);
367 			freed++;
368 		}
369 		huge_pagevec_release(&pvec);
370 	}
371 	BUG_ON(!lstart && mapping->nrpages);
372 	hugetlb_unreserve_pages(inode, start, freed);
373 }
374 
375 static void hugetlbfs_delete_inode(struct inode *inode)
376 {
377 	truncate_hugepages(inode, 0);
378 	clear_inode(inode);
379 }
380 
381 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
382 {
383 	if (generic_detach_inode(inode)) {
384 		truncate_hugepages(inode, 0);
385 		clear_inode(inode);
386 		destroy_inode(inode);
387 	}
388 }
389 
390 static void hugetlbfs_drop_inode(struct inode *inode)
391 {
392 	if (!inode->i_nlink)
393 		generic_delete_inode(inode);
394 	else
395 		hugetlbfs_forget_inode(inode);
396 }
397 
398 static inline void
399 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
400 {
401 	struct vm_area_struct *vma;
402 	struct prio_tree_iter iter;
403 
404 	vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
405 		unsigned long v_offset;
406 
407 		/*
408 		 * Can the expression below overflow on 32-bit arches?
409 		 * No, because the prio_tree returns us only those vmas
410 		 * which overlap the truncated area starting at pgoff,
411 		 * and no vma on a 32-bit arch can span beyond the 4GB.
412 		 */
413 		if (vma->vm_pgoff < pgoff)
414 			v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
415 		else
416 			v_offset = 0;
417 
418 		__unmap_hugepage_range(vma,
419 				vma->vm_start + v_offset, vma->vm_end, NULL);
420 	}
421 }
422 
423 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
424 {
425 	pgoff_t pgoff;
426 	struct address_space *mapping = inode->i_mapping;
427 	struct hstate *h = hstate_inode(inode);
428 
429 	BUG_ON(offset & ~huge_page_mask(h));
430 	pgoff = offset >> PAGE_SHIFT;
431 
432 	i_size_write(inode, offset);
433 	spin_lock(&mapping->i_mmap_lock);
434 	if (!prio_tree_empty(&mapping->i_mmap))
435 		hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
436 	spin_unlock(&mapping->i_mmap_lock);
437 	truncate_hugepages(inode, offset);
438 	return 0;
439 }
440 
441 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
442 {
443 	struct inode *inode = dentry->d_inode;
444 	struct hstate *h = hstate_inode(inode);
445 	int error;
446 	unsigned int ia_valid = attr->ia_valid;
447 
448 	BUG_ON(!inode);
449 
450 	error = inode_change_ok(inode, attr);
451 	if (error)
452 		goto out;
453 
454 	if (ia_valid & ATTR_SIZE) {
455 		error = -EINVAL;
456 		if (!(attr->ia_size & ~huge_page_mask(h)))
457 			error = hugetlb_vmtruncate(inode, attr->ia_size);
458 		if (error)
459 			goto out;
460 		attr->ia_valid &= ~ATTR_SIZE;
461 	}
462 	error = inode_setattr(inode, attr);
463 out:
464 	return error;
465 }
466 
467 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
468 					gid_t gid, int mode, dev_t dev)
469 {
470 	struct inode *inode;
471 
472 	inode = new_inode(sb);
473 	if (inode) {
474 		struct hugetlbfs_inode_info *info;
475 		inode->i_mode = mode;
476 		inode->i_uid = uid;
477 		inode->i_gid = gid;
478 		inode->i_mapping->a_ops = &hugetlbfs_aops;
479 		inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
480 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
481 		INIT_LIST_HEAD(&inode->i_mapping->private_list);
482 		info = HUGETLBFS_I(inode);
483 		/*
484 		 * The policy is initialized here even if we are creating a
485 		 * private inode because initialization simply creates an
486 		 * an empty rb tree and calls spin_lock_init(), later when we
487 		 * call mpol_free_shared_policy() it will just return because
488 		 * the rb tree will still be empty.
489 		 */
490 		mpol_shared_policy_init(&info->policy, NULL);
491 		switch (mode & S_IFMT) {
492 		default:
493 			init_special_inode(inode, mode, dev);
494 			break;
495 		case S_IFREG:
496 			inode->i_op = &hugetlbfs_inode_operations;
497 			inode->i_fop = &hugetlbfs_file_operations;
498 			break;
499 		case S_IFDIR:
500 			inode->i_op = &hugetlbfs_dir_inode_operations;
501 			inode->i_fop = &simple_dir_operations;
502 
503 			/* directory inodes start off with i_nlink == 2 (for "." entry) */
504 			inc_nlink(inode);
505 			break;
506 		case S_IFLNK:
507 			inode->i_op = &page_symlink_inode_operations;
508 			break;
509 		}
510 	}
511 	return inode;
512 }
513 
514 /*
515  * File creation. Allocate an inode, and we're done..
516  */
517 static int hugetlbfs_mknod(struct inode *dir,
518 			struct dentry *dentry, int mode, dev_t dev)
519 {
520 	struct inode *inode;
521 	int error = -ENOSPC;
522 	gid_t gid;
523 
524 	if (dir->i_mode & S_ISGID) {
525 		gid = dir->i_gid;
526 		if (S_ISDIR(mode))
527 			mode |= S_ISGID;
528 	} else {
529 		gid = current_fsgid();
530 	}
531 	inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
532 	if (inode) {
533 		dir->i_ctime = dir->i_mtime = CURRENT_TIME;
534 		d_instantiate(dentry, inode);
535 		dget(dentry);	/* Extra count - pin the dentry in core */
536 		error = 0;
537 	}
538 	return error;
539 }
540 
541 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
542 {
543 	int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
544 	if (!retval)
545 		inc_nlink(dir);
546 	return retval;
547 }
548 
549 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
550 {
551 	return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
552 }
553 
554 static int hugetlbfs_symlink(struct inode *dir,
555 			struct dentry *dentry, const char *symname)
556 {
557 	struct inode *inode;
558 	int error = -ENOSPC;
559 	gid_t gid;
560 
561 	if (dir->i_mode & S_ISGID)
562 		gid = dir->i_gid;
563 	else
564 		gid = current_fsgid();
565 
566 	inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
567 					gid, S_IFLNK|S_IRWXUGO, 0);
568 	if (inode) {
569 		int l = strlen(symname)+1;
570 		error = page_symlink(inode, symname, l);
571 		if (!error) {
572 			d_instantiate(dentry, inode);
573 			dget(dentry);
574 		} else
575 			iput(inode);
576 	}
577 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
578 
579 	return error;
580 }
581 
582 /*
583  * mark the head page dirty
584  */
585 static int hugetlbfs_set_page_dirty(struct page *page)
586 {
587 	struct page *head = compound_head(page);
588 
589 	SetPageDirty(head);
590 	return 0;
591 }
592 
593 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
594 {
595 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
596 	struct hstate *h = hstate_inode(dentry->d_inode);
597 
598 	buf->f_type = HUGETLBFS_MAGIC;
599 	buf->f_bsize = huge_page_size(h);
600 	if (sbinfo) {
601 		spin_lock(&sbinfo->stat_lock);
602 		/* If no limits set, just report 0 for max/free/used
603 		 * blocks, like simple_statfs() */
604 		if (sbinfo->max_blocks >= 0) {
605 			buf->f_blocks = sbinfo->max_blocks;
606 			buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
607 			buf->f_files = sbinfo->max_inodes;
608 			buf->f_ffree = sbinfo->free_inodes;
609 		}
610 		spin_unlock(&sbinfo->stat_lock);
611 	}
612 	buf->f_namelen = NAME_MAX;
613 	return 0;
614 }
615 
616 static void hugetlbfs_put_super(struct super_block *sb)
617 {
618 	struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
619 
620 	if (sbi) {
621 		sb->s_fs_info = NULL;
622 		kfree(sbi);
623 	}
624 }
625 
626 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
627 {
628 	if (sbinfo->free_inodes >= 0) {
629 		spin_lock(&sbinfo->stat_lock);
630 		if (unlikely(!sbinfo->free_inodes)) {
631 			spin_unlock(&sbinfo->stat_lock);
632 			return 0;
633 		}
634 		sbinfo->free_inodes--;
635 		spin_unlock(&sbinfo->stat_lock);
636 	}
637 
638 	return 1;
639 }
640 
641 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
642 {
643 	if (sbinfo->free_inodes >= 0) {
644 		spin_lock(&sbinfo->stat_lock);
645 		sbinfo->free_inodes++;
646 		spin_unlock(&sbinfo->stat_lock);
647 	}
648 }
649 
650 
651 static struct kmem_cache *hugetlbfs_inode_cachep;
652 
653 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
654 {
655 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
656 	struct hugetlbfs_inode_info *p;
657 
658 	if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
659 		return NULL;
660 	p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
661 	if (unlikely(!p)) {
662 		hugetlbfs_inc_free_inodes(sbinfo);
663 		return NULL;
664 	}
665 	return &p->vfs_inode;
666 }
667 
668 static void hugetlbfs_destroy_inode(struct inode *inode)
669 {
670 	hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
671 	mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
672 	kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
673 }
674 
675 static const struct address_space_operations hugetlbfs_aops = {
676 	.write_begin	= hugetlbfs_write_begin,
677 	.write_end	= hugetlbfs_write_end,
678 	.set_page_dirty	= hugetlbfs_set_page_dirty,
679 };
680 
681 
682 static void init_once(void *foo)
683 {
684 	struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
685 
686 	inode_init_once(&ei->vfs_inode);
687 }
688 
689 const struct file_operations hugetlbfs_file_operations = {
690 	.read			= hugetlbfs_read,
691 	.mmap			= hugetlbfs_file_mmap,
692 	.fsync			= simple_sync_file,
693 	.get_unmapped_area	= hugetlb_get_unmapped_area,
694 };
695 
696 static const struct inode_operations hugetlbfs_dir_inode_operations = {
697 	.create		= hugetlbfs_create,
698 	.lookup		= simple_lookup,
699 	.link		= simple_link,
700 	.unlink		= simple_unlink,
701 	.symlink	= hugetlbfs_symlink,
702 	.mkdir		= hugetlbfs_mkdir,
703 	.rmdir		= simple_rmdir,
704 	.mknod		= hugetlbfs_mknod,
705 	.rename		= simple_rename,
706 	.setattr	= hugetlbfs_setattr,
707 };
708 
709 static const struct inode_operations hugetlbfs_inode_operations = {
710 	.setattr	= hugetlbfs_setattr,
711 };
712 
713 static const struct super_operations hugetlbfs_ops = {
714 	.alloc_inode    = hugetlbfs_alloc_inode,
715 	.destroy_inode  = hugetlbfs_destroy_inode,
716 	.statfs		= hugetlbfs_statfs,
717 	.delete_inode	= hugetlbfs_delete_inode,
718 	.drop_inode	= hugetlbfs_drop_inode,
719 	.put_super	= hugetlbfs_put_super,
720 	.show_options	= generic_show_options,
721 };
722 
723 static int
724 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
725 {
726 	char *p, *rest;
727 	substring_t args[MAX_OPT_ARGS];
728 	int option;
729 	unsigned long long size = 0;
730 	enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
731 
732 	if (!options)
733 		return 0;
734 
735 	while ((p = strsep(&options, ",")) != NULL) {
736 		int token;
737 		if (!*p)
738 			continue;
739 
740 		token = match_token(p, tokens, args);
741 		switch (token) {
742 		case Opt_uid:
743 			if (match_int(&args[0], &option))
744  				goto bad_val;
745 			pconfig->uid = option;
746 			break;
747 
748 		case Opt_gid:
749 			if (match_int(&args[0], &option))
750  				goto bad_val;
751 			pconfig->gid = option;
752 			break;
753 
754 		case Opt_mode:
755 			if (match_octal(&args[0], &option))
756  				goto bad_val;
757 			pconfig->mode = option & 01777U;
758 			break;
759 
760 		case Opt_size: {
761 			/* memparse() will accept a K/M/G without a digit */
762 			if (!isdigit(*args[0].from))
763 				goto bad_val;
764 			size = memparse(args[0].from, &rest);
765 			setsize = SIZE_STD;
766 			if (*rest == '%')
767 				setsize = SIZE_PERCENT;
768 			break;
769 		}
770 
771 		case Opt_nr_inodes:
772 			/* memparse() will accept a K/M/G without a digit */
773 			if (!isdigit(*args[0].from))
774 				goto bad_val;
775 			pconfig->nr_inodes = memparse(args[0].from, &rest);
776 			break;
777 
778 		case Opt_pagesize: {
779 			unsigned long ps;
780 			ps = memparse(args[0].from, &rest);
781 			pconfig->hstate = size_to_hstate(ps);
782 			if (!pconfig->hstate) {
783 				printk(KERN_ERR
784 				"hugetlbfs: Unsupported page size %lu MB\n",
785 					ps >> 20);
786 				return -EINVAL;
787 			}
788 			break;
789 		}
790 
791 		default:
792 			printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
793 				 p);
794 			return -EINVAL;
795 			break;
796 		}
797 	}
798 
799 	/* Do size after hstate is set up */
800 	if (setsize > NO_SIZE) {
801 		struct hstate *h = pconfig->hstate;
802 		if (setsize == SIZE_PERCENT) {
803 			size <<= huge_page_shift(h);
804 			size *= h->max_huge_pages;
805 			do_div(size, 100);
806 		}
807 		pconfig->nr_blocks = (size >> huge_page_shift(h));
808 	}
809 
810 	return 0;
811 
812 bad_val:
813  	printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
814 	       args[0].from, p);
815  	return -EINVAL;
816 }
817 
818 static int
819 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
820 {
821 	struct inode * inode;
822 	struct dentry * root;
823 	int ret;
824 	struct hugetlbfs_config config;
825 	struct hugetlbfs_sb_info *sbinfo;
826 
827 	save_mount_options(sb, data);
828 
829 	config.nr_blocks = -1; /* No limit on size by default */
830 	config.nr_inodes = -1; /* No limit on number of inodes by default */
831 	config.uid = current_fsuid();
832 	config.gid = current_fsgid();
833 	config.mode = 0755;
834 	config.hstate = &default_hstate;
835 	ret = hugetlbfs_parse_options(data, &config);
836 	if (ret)
837 		return ret;
838 
839 	sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
840 	if (!sbinfo)
841 		return -ENOMEM;
842 	sb->s_fs_info = sbinfo;
843 	sbinfo->hstate = config.hstate;
844 	spin_lock_init(&sbinfo->stat_lock);
845 	sbinfo->max_blocks = config.nr_blocks;
846 	sbinfo->free_blocks = config.nr_blocks;
847 	sbinfo->max_inodes = config.nr_inodes;
848 	sbinfo->free_inodes = config.nr_inodes;
849 	sb->s_maxbytes = MAX_LFS_FILESIZE;
850 	sb->s_blocksize = huge_page_size(config.hstate);
851 	sb->s_blocksize_bits = huge_page_shift(config.hstate);
852 	sb->s_magic = HUGETLBFS_MAGIC;
853 	sb->s_op = &hugetlbfs_ops;
854 	sb->s_time_gran = 1;
855 	inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
856 					S_IFDIR | config.mode, 0);
857 	if (!inode)
858 		goto out_free;
859 
860 	root = d_alloc_root(inode);
861 	if (!root) {
862 		iput(inode);
863 		goto out_free;
864 	}
865 	sb->s_root = root;
866 	return 0;
867 out_free:
868 	kfree(sbinfo);
869 	return -ENOMEM;
870 }
871 
872 int hugetlb_get_quota(struct address_space *mapping, long delta)
873 {
874 	int ret = 0;
875 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
876 
877 	if (sbinfo->free_blocks > -1) {
878 		spin_lock(&sbinfo->stat_lock);
879 		if (sbinfo->free_blocks - delta >= 0)
880 			sbinfo->free_blocks -= delta;
881 		else
882 			ret = -ENOMEM;
883 		spin_unlock(&sbinfo->stat_lock);
884 	}
885 
886 	return ret;
887 }
888 
889 void hugetlb_put_quota(struct address_space *mapping, long delta)
890 {
891 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
892 
893 	if (sbinfo->free_blocks > -1) {
894 		spin_lock(&sbinfo->stat_lock);
895 		sbinfo->free_blocks += delta;
896 		spin_unlock(&sbinfo->stat_lock);
897 	}
898 }
899 
900 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
901 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
902 {
903 	return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
904 }
905 
906 static struct file_system_type hugetlbfs_fs_type = {
907 	.name		= "hugetlbfs",
908 	.get_sb		= hugetlbfs_get_sb,
909 	.kill_sb	= kill_litter_super,
910 };
911 
912 static struct vfsmount *hugetlbfs_vfsmount;
913 
914 static int can_do_hugetlb_shm(void)
915 {
916 	return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
917 }
918 
919 struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag,
920 				struct user_struct **user, int creat_flags)
921 {
922 	int error = -ENOMEM;
923 	struct file *file;
924 	struct inode *inode;
925 	struct dentry *dentry, *root;
926 	struct qstr quick_string;
927 
928 	*user = NULL;
929 	if (!hugetlbfs_vfsmount)
930 		return ERR_PTR(-ENOENT);
931 
932 	if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
933 		*user = current_user();
934 		if (user_shm_lock(size, *user)) {
935 			WARN_ONCE(1,
936 			  "Using mlock ulimits for SHM_HUGETLB deprecated\n");
937 		} else {
938 			*user = NULL;
939 			return ERR_PTR(-EPERM);
940 		}
941 	}
942 
943 	root = hugetlbfs_vfsmount->mnt_root;
944 	quick_string.name = name;
945 	quick_string.len = strlen(quick_string.name);
946 	quick_string.hash = 0;
947 	dentry = d_alloc(root, &quick_string);
948 	if (!dentry)
949 		goto out_shm_unlock;
950 
951 	error = -ENOSPC;
952 	inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
953 				current_fsgid(), S_IFREG | S_IRWXUGO, 0);
954 	if (!inode)
955 		goto out_dentry;
956 
957 	error = -ENOMEM;
958 	if (hugetlb_reserve_pages(inode, 0,
959 			size >> huge_page_shift(hstate_inode(inode)), NULL,
960 			acctflag))
961 		goto out_inode;
962 
963 	d_instantiate(dentry, inode);
964 	inode->i_size = size;
965 	inode->i_nlink = 0;
966 
967 	error = -ENFILE;
968 	file = alloc_file(hugetlbfs_vfsmount, dentry,
969 			FMODE_WRITE | FMODE_READ,
970 			&hugetlbfs_file_operations);
971 	if (!file)
972 		goto out_dentry; /* inode is already attached */
973 	ima_counts_get(file);
974 
975 	return file;
976 
977 out_inode:
978 	iput(inode);
979 out_dentry:
980 	dput(dentry);
981 out_shm_unlock:
982 	if (*user) {
983 		user_shm_unlock(size, *user);
984 		*user = NULL;
985 	}
986 	return ERR_PTR(error);
987 }
988 
989 static int __init init_hugetlbfs_fs(void)
990 {
991 	int error;
992 	struct vfsmount *vfsmount;
993 
994 	error = bdi_init(&hugetlbfs_backing_dev_info);
995 	if (error)
996 		return error;
997 
998 	hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
999 					sizeof(struct hugetlbfs_inode_info),
1000 					0, 0, init_once);
1001 	if (hugetlbfs_inode_cachep == NULL)
1002 		goto out2;
1003 
1004 	error = register_filesystem(&hugetlbfs_fs_type);
1005 	if (error)
1006 		goto out;
1007 
1008 	vfsmount = kern_mount(&hugetlbfs_fs_type);
1009 
1010 	if (!IS_ERR(vfsmount)) {
1011 		hugetlbfs_vfsmount = vfsmount;
1012 		return 0;
1013 	}
1014 
1015 	error = PTR_ERR(vfsmount);
1016 
1017  out:
1018 	if (error)
1019 		kmem_cache_destroy(hugetlbfs_inode_cachep);
1020  out2:
1021 	bdi_destroy(&hugetlbfs_backing_dev_info);
1022 	return error;
1023 }
1024 
1025 static void __exit exit_hugetlbfs_fs(void)
1026 {
1027 	kmem_cache_destroy(hugetlbfs_inode_cachep);
1028 	unregister_filesystem(&hugetlbfs_fs_type);
1029 	bdi_destroy(&hugetlbfs_backing_dev_info);
1030 }
1031 
1032 module_init(init_hugetlbfs_fs)
1033 module_exit(exit_hugetlbfs_fs)
1034 
1035 MODULE_LICENSE("GPL");
1036