Version:  2.0.40 2.2.26 2.4.37 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2

Linux/fs/hugetlbfs/inode.c

  1 /*
  2  * hugetlbpage-backed filesystem.  Based on ramfs.
  3  *
  4  * Nadia Yvette Chambers, 2002
  5  *
  6  * Copyright (C) 2002 Linus Torvalds.
  7  */
  8 
  9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 10 
 11 #include <linux/module.h>
 12 #include <linux/thread_info.h>
 13 #include <asm/current.h>
 14 #include <linux/sched.h>                /* remove ASAP */
 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/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 <asm/uaccess.h>
 40 
 41 static const struct super_operations hugetlbfs_ops;
 42 static const struct address_space_operations hugetlbfs_aops;
 43 const struct file_operations hugetlbfs_file_operations;
 44 static const struct inode_operations hugetlbfs_dir_inode_operations;
 45 static const struct inode_operations hugetlbfs_inode_operations;
 46 
 47 struct hugetlbfs_config {
 48         kuid_t   uid;
 49         kgid_t   gid;
 50         umode_t mode;
 51         long    max_hpages;
 52         long    nr_inodes;
 53         struct hstate *hstate;
 54         long    min_hpages;
 55 };
 56 
 57 struct hugetlbfs_inode_info {
 58         struct shared_policy policy;
 59         struct inode vfs_inode;
 60 };
 61 
 62 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
 63 {
 64         return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
 65 }
 66 
 67 int sysctl_hugetlb_shm_group;
 68 
 69 enum {
 70         Opt_size, Opt_nr_inodes,
 71         Opt_mode, Opt_uid, Opt_gid,
 72         Opt_pagesize, Opt_min_size,
 73         Opt_err,
 74 };
 75 
 76 static const match_table_t tokens = {
 77         {Opt_size,      "size=%s"},
 78         {Opt_nr_inodes, "nr_inodes=%s"},
 79         {Opt_mode,      "mode=%o"},
 80         {Opt_uid,       "uid=%u"},
 81         {Opt_gid,       "gid=%u"},
 82         {Opt_pagesize,  "pagesize=%s"},
 83         {Opt_min_size,  "min_size=%s"},
 84         {Opt_err,       NULL},
 85 };
 86 
 87 static void huge_pagevec_release(struct pagevec *pvec)
 88 {
 89         int i;
 90 
 91         for (i = 0; i < pagevec_count(pvec); ++i)
 92                 put_page(pvec->pages[i]);
 93 
 94         pagevec_reinit(pvec);
 95 }
 96 
 97 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 98 {
 99         struct inode *inode = file_inode(file);
100         loff_t len, vma_len;
101         int ret;
102         struct hstate *h = hstate_file(file);
103 
104         /*
105          * vma address alignment (but not the pgoff alignment) has
106          * already been checked by prepare_hugepage_range.  If you add
107          * any error returns here, do so after setting VM_HUGETLB, so
108          * is_vm_hugetlb_page tests below unmap_region go the right
109          * way when do_mmap_pgoff unwinds (may be important on powerpc
110          * and ia64).
111          */
112         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
113         vma->vm_ops = &hugetlb_vm_ops;
114 
115         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
116                 return -EINVAL;
117 
118         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
119 
120         mutex_lock(&inode->i_mutex);
121         file_accessed(file);
122 
123         ret = -ENOMEM;
124         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
125 
126         if (hugetlb_reserve_pages(inode,
127                                 vma->vm_pgoff >> huge_page_order(h),
128                                 len >> huge_page_shift(h), vma,
129                                 vma->vm_flags))
130                 goto out;
131 
132         ret = 0;
133         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
134                 inode->i_size = len;
135 out:
136         mutex_unlock(&inode->i_mutex);
137 
138         return ret;
139 }
140 
141 /*
142  * Called under down_write(mmap_sem).
143  */
144 
145 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
146 static unsigned long
147 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
148                 unsigned long len, unsigned long pgoff, unsigned long flags)
149 {
150         struct mm_struct *mm = current->mm;
151         struct vm_area_struct *vma;
152         struct hstate *h = hstate_file(file);
153         struct vm_unmapped_area_info info;
154 
155         if (len & ~huge_page_mask(h))
156                 return -EINVAL;
157         if (len > TASK_SIZE)
158                 return -ENOMEM;
159 
160         if (flags & MAP_FIXED) {
161                 if (prepare_hugepage_range(file, addr, len))
162                         return -EINVAL;
163                 return addr;
164         }
165 
166         if (addr) {
167                 addr = ALIGN(addr, huge_page_size(h));
168                 vma = find_vma(mm, addr);
169                 if (TASK_SIZE - len >= addr &&
170                     (!vma || addr + len <= vma->vm_start))
171                         return addr;
172         }
173 
174         info.flags = 0;
175         info.length = len;
176         info.low_limit = TASK_UNMAPPED_BASE;
177         info.high_limit = TASK_SIZE;
178         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
179         info.align_offset = 0;
180         return vm_unmapped_area(&info);
181 }
182 #endif
183 
184 static size_t
185 hugetlbfs_read_actor(struct page *page, unsigned long offset,
186                         struct iov_iter *to, unsigned long size)
187 {
188         size_t copied = 0;
189         int i, chunksize;
190 
191         /* Find which 4k chunk and offset with in that chunk */
192         i = offset >> PAGE_CACHE_SHIFT;
193         offset = offset & ~PAGE_CACHE_MASK;
194 
195         while (size) {
196                 size_t n;
197                 chunksize = PAGE_CACHE_SIZE;
198                 if (offset)
199                         chunksize -= offset;
200                 if (chunksize > size)
201                         chunksize = size;
202                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
203                 copied += n;
204                 if (n != chunksize)
205                         return copied;
206                 offset = 0;
207                 size -= chunksize;
208                 i++;
209         }
210         return copied;
211 }
212 
213 /*
214  * Support for read() - Find the page attached to f_mapping and copy out the
215  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
216  * since it has PAGE_CACHE_SIZE assumptions.
217  */
218 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
219 {
220         struct file *file = iocb->ki_filp;
221         struct hstate *h = hstate_file(file);
222         struct address_space *mapping = file->f_mapping;
223         struct inode *inode = mapping->host;
224         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
225         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
226         unsigned long end_index;
227         loff_t isize;
228         ssize_t retval = 0;
229 
230         while (iov_iter_count(to)) {
231                 struct page *page;
232                 size_t nr, copied;
233 
234                 /* nr is the maximum number of bytes to copy from this page */
235                 nr = huge_page_size(h);
236                 isize = i_size_read(inode);
237                 if (!isize)
238                         break;
239                 end_index = (isize - 1) >> huge_page_shift(h);
240                 if (index > end_index)
241                         break;
242                 if (index == end_index) {
243                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
244                         if (nr <= offset)
245                                 break;
246                 }
247                 nr = nr - offset;
248 
249                 /* Find the page */
250                 page = find_lock_page(mapping, index);
251                 if (unlikely(page == NULL)) {
252                         /*
253                          * We have a HOLE, zero out the user-buffer for the
254                          * length of the hole or request.
255                          */
256                         copied = iov_iter_zero(nr, to);
257                 } else {
258                         unlock_page(page);
259 
260                         /*
261                          * We have the page, copy it to user space buffer.
262                          */
263                         copied = hugetlbfs_read_actor(page, offset, to, nr);
264                         page_cache_release(page);
265                 }
266                 offset += copied;
267                 retval += copied;
268                 if (copied != nr && iov_iter_count(to)) {
269                         if (!retval)
270                                 retval = -EFAULT;
271                         break;
272                 }
273                 index += offset >> huge_page_shift(h);
274                 offset &= ~huge_page_mask(h);
275         }
276         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
277         return retval;
278 }
279 
280 static int hugetlbfs_write_begin(struct file *file,
281                         struct address_space *mapping,
282                         loff_t pos, unsigned len, unsigned flags,
283                         struct page **pagep, void **fsdata)
284 {
285         return -EINVAL;
286 }
287 
288 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
289                         loff_t pos, unsigned len, unsigned copied,
290                         struct page *page, void *fsdata)
291 {
292         BUG();
293         return -EINVAL;
294 }
295 
296 static void truncate_huge_page(struct page *page)
297 {
298         ClearPageDirty(page);
299         ClearPageUptodate(page);
300         delete_from_page_cache(page);
301 }
302 
303 static void truncate_hugepages(struct inode *inode, loff_t lstart)
304 {
305         struct hstate *h = hstate_inode(inode);
306         struct address_space *mapping = &inode->i_data;
307         const pgoff_t start = lstart >> huge_page_shift(h);
308         struct pagevec pvec;
309         pgoff_t next;
310         int i, freed = 0;
311 
312         pagevec_init(&pvec, 0);
313         next = start;
314         while (1) {
315                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
316                         if (next == start)
317                                 break;
318                         next = start;
319                         continue;
320                 }
321 
322                 for (i = 0; i < pagevec_count(&pvec); ++i) {
323                         struct page *page = pvec.pages[i];
324 
325                         lock_page(page);
326                         if (page->index > next)
327                                 next = page->index;
328                         ++next;
329                         truncate_huge_page(page);
330                         unlock_page(page);
331                         freed++;
332                 }
333                 huge_pagevec_release(&pvec);
334         }
335         BUG_ON(!lstart && mapping->nrpages);
336         hugetlb_unreserve_pages(inode, start, freed);
337 }
338 
339 static void hugetlbfs_evict_inode(struct inode *inode)
340 {
341         struct resv_map *resv_map;
342 
343         truncate_hugepages(inode, 0);
344         resv_map = (struct resv_map *)inode->i_mapping->private_data;
345         /* root inode doesn't have the resv_map, so we should check it */
346         if (resv_map)
347                 resv_map_release(&resv_map->refs);
348         clear_inode(inode);
349 }
350 
351 static inline void
352 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
353 {
354         struct vm_area_struct *vma;
355 
356         vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
357                 unsigned long v_offset;
358 
359                 /*
360                  * Can the expression below overflow on 32-bit arches?
361                  * No, because the interval tree returns us only those vmas
362                  * which overlap the truncated area starting at pgoff,
363                  * and no vma on a 32-bit arch can span beyond the 4GB.
364                  */
365                 if (vma->vm_pgoff < pgoff)
366                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
367                 else
368                         v_offset = 0;
369 
370                 unmap_hugepage_range(vma, vma->vm_start + v_offset,
371                                      vma->vm_end, NULL);
372         }
373 }
374 
375 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
376 {
377         pgoff_t pgoff;
378         struct address_space *mapping = inode->i_mapping;
379         struct hstate *h = hstate_inode(inode);
380 
381         BUG_ON(offset & ~huge_page_mask(h));
382         pgoff = offset >> PAGE_SHIFT;
383 
384         i_size_write(inode, offset);
385         i_mmap_lock_write(mapping);
386         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
387                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
388         i_mmap_unlock_write(mapping);
389         truncate_hugepages(inode, offset);
390         return 0;
391 }
392 
393 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
394 {
395         struct inode *inode = d_inode(dentry);
396         struct hstate *h = hstate_inode(inode);
397         int error;
398         unsigned int ia_valid = attr->ia_valid;
399 
400         BUG_ON(!inode);
401 
402         error = inode_change_ok(inode, attr);
403         if (error)
404                 return error;
405 
406         if (ia_valid & ATTR_SIZE) {
407                 error = -EINVAL;
408                 if (attr->ia_size & ~huge_page_mask(h))
409                         return -EINVAL;
410                 error = hugetlb_vmtruncate(inode, attr->ia_size);
411                 if (error)
412                         return error;
413         }
414 
415         setattr_copy(inode, attr);
416         mark_inode_dirty(inode);
417         return 0;
418 }
419 
420 static struct inode *hugetlbfs_get_root(struct super_block *sb,
421                                         struct hugetlbfs_config *config)
422 {
423         struct inode *inode;
424 
425         inode = new_inode(sb);
426         if (inode) {
427                 struct hugetlbfs_inode_info *info;
428                 inode->i_ino = get_next_ino();
429                 inode->i_mode = S_IFDIR | config->mode;
430                 inode->i_uid = config->uid;
431                 inode->i_gid = config->gid;
432                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
433                 info = HUGETLBFS_I(inode);
434                 mpol_shared_policy_init(&info->policy, NULL);
435                 inode->i_op = &hugetlbfs_dir_inode_operations;
436                 inode->i_fop = &simple_dir_operations;
437                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
438                 inc_nlink(inode);
439                 lockdep_annotate_inode_mutex_key(inode);
440         }
441         return inode;
442 }
443 
444 /*
445  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
446  * be taken from reclaim -- unlike regular filesystems. This needs an
447  * annotation because huge_pmd_share() does an allocation under
448  * i_mmap_rwsem.
449  */
450 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
451 
452 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
453                                         struct inode *dir,
454                                         umode_t mode, dev_t dev)
455 {
456         struct inode *inode;
457         struct resv_map *resv_map;
458 
459         resv_map = resv_map_alloc();
460         if (!resv_map)
461                 return NULL;
462 
463         inode = new_inode(sb);
464         if (inode) {
465                 struct hugetlbfs_inode_info *info;
466                 inode->i_ino = get_next_ino();
467                 inode_init_owner(inode, dir, mode);
468                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
469                                 &hugetlbfs_i_mmap_rwsem_key);
470                 inode->i_mapping->a_ops = &hugetlbfs_aops;
471                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
472                 inode->i_mapping->private_data = resv_map;
473                 info = HUGETLBFS_I(inode);
474                 /*
475                  * The policy is initialized here even if we are creating a
476                  * private inode because initialization simply creates an
477                  * an empty rb tree and calls spin_lock_init(), later when we
478                  * call mpol_free_shared_policy() it will just return because
479                  * the rb tree will still be empty.
480                  */
481                 mpol_shared_policy_init(&info->policy, NULL);
482                 switch (mode & S_IFMT) {
483                 default:
484                         init_special_inode(inode, mode, dev);
485                         break;
486                 case S_IFREG:
487                         inode->i_op = &hugetlbfs_inode_operations;
488                         inode->i_fop = &hugetlbfs_file_operations;
489                         break;
490                 case S_IFDIR:
491                         inode->i_op = &hugetlbfs_dir_inode_operations;
492                         inode->i_fop = &simple_dir_operations;
493 
494                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
495                         inc_nlink(inode);
496                         break;
497                 case S_IFLNK:
498                         inode->i_op = &page_symlink_inode_operations;
499                         break;
500                 }
501                 lockdep_annotate_inode_mutex_key(inode);
502         } else
503                 kref_put(&resv_map->refs, resv_map_release);
504 
505         return inode;
506 }
507 
508 /*
509  * File creation. Allocate an inode, and we're done..
510  */
511 static int hugetlbfs_mknod(struct inode *dir,
512                         struct dentry *dentry, umode_t mode, dev_t dev)
513 {
514         struct inode *inode;
515         int error = -ENOSPC;
516 
517         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
518         if (inode) {
519                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
520                 d_instantiate(dentry, inode);
521                 dget(dentry);   /* Extra count - pin the dentry in core */
522                 error = 0;
523         }
524         return error;
525 }
526 
527 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
528 {
529         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
530         if (!retval)
531                 inc_nlink(dir);
532         return retval;
533 }
534 
535 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
536 {
537         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
538 }
539 
540 static int hugetlbfs_symlink(struct inode *dir,
541                         struct dentry *dentry, const char *symname)
542 {
543         struct inode *inode;
544         int error = -ENOSPC;
545 
546         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
547         if (inode) {
548                 int l = strlen(symname)+1;
549                 error = page_symlink(inode, symname, l);
550                 if (!error) {
551                         d_instantiate(dentry, inode);
552                         dget(dentry);
553                 } else
554                         iput(inode);
555         }
556         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
557 
558         return error;
559 }
560 
561 /*
562  * mark the head page dirty
563  */
564 static int hugetlbfs_set_page_dirty(struct page *page)
565 {
566         struct page *head = compound_head(page);
567 
568         SetPageDirty(head);
569         return 0;
570 }
571 
572 static int hugetlbfs_migrate_page(struct address_space *mapping,
573                                 struct page *newpage, struct page *page,
574                                 enum migrate_mode mode)
575 {
576         int rc;
577 
578         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
579         if (rc != MIGRATEPAGE_SUCCESS)
580                 return rc;
581         migrate_page_copy(newpage, page);
582 
583         return MIGRATEPAGE_SUCCESS;
584 }
585 
586 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
587 {
588         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
589         struct hstate *h = hstate_inode(d_inode(dentry));
590 
591         buf->f_type = HUGETLBFS_MAGIC;
592         buf->f_bsize = huge_page_size(h);
593         if (sbinfo) {
594                 spin_lock(&sbinfo->stat_lock);
595                 /* If no limits set, just report 0 for max/free/used
596                  * blocks, like simple_statfs() */
597                 if (sbinfo->spool) {
598                         long free_pages;
599 
600                         spin_lock(&sbinfo->spool->lock);
601                         buf->f_blocks = sbinfo->spool->max_hpages;
602                         free_pages = sbinfo->spool->max_hpages
603                                 - sbinfo->spool->used_hpages;
604                         buf->f_bavail = buf->f_bfree = free_pages;
605                         spin_unlock(&sbinfo->spool->lock);
606                         buf->f_files = sbinfo->max_inodes;
607                         buf->f_ffree = sbinfo->free_inodes;
608                 }
609                 spin_unlock(&sbinfo->stat_lock);
610         }
611         buf->f_namelen = NAME_MAX;
612         return 0;
613 }
614 
615 static void hugetlbfs_put_super(struct super_block *sb)
616 {
617         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
618 
619         if (sbi) {
620                 sb->s_fs_info = NULL;
621 
622                 if (sbi->spool)
623                         hugepage_put_subpool(sbi->spool);
624 
625                 kfree(sbi);
626         }
627 }
628 
629 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
630 {
631         if (sbinfo->free_inodes >= 0) {
632                 spin_lock(&sbinfo->stat_lock);
633                 if (unlikely(!sbinfo->free_inodes)) {
634                         spin_unlock(&sbinfo->stat_lock);
635                         return 0;
636                 }
637                 sbinfo->free_inodes--;
638                 spin_unlock(&sbinfo->stat_lock);
639         }
640 
641         return 1;
642 }
643 
644 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
645 {
646         if (sbinfo->free_inodes >= 0) {
647                 spin_lock(&sbinfo->stat_lock);
648                 sbinfo->free_inodes++;
649                 spin_unlock(&sbinfo->stat_lock);
650         }
651 }
652 
653 
654 static struct kmem_cache *hugetlbfs_inode_cachep;
655 
656 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
657 {
658         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
659         struct hugetlbfs_inode_info *p;
660 
661         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
662                 return NULL;
663         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
664         if (unlikely(!p)) {
665                 hugetlbfs_inc_free_inodes(sbinfo);
666                 return NULL;
667         }
668         return &p->vfs_inode;
669 }
670 
671 static void hugetlbfs_i_callback(struct rcu_head *head)
672 {
673         struct inode *inode = container_of(head, struct inode, i_rcu);
674         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
675 }
676 
677 static void hugetlbfs_destroy_inode(struct inode *inode)
678 {
679         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
680         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
681         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
682 }
683 
684 static const struct address_space_operations hugetlbfs_aops = {
685         .write_begin    = hugetlbfs_write_begin,
686         .write_end      = hugetlbfs_write_end,
687         .set_page_dirty = hugetlbfs_set_page_dirty,
688         .migratepage    = hugetlbfs_migrate_page,
689 };
690 
691 
692 static void init_once(void *foo)
693 {
694         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
695 
696         inode_init_once(&ei->vfs_inode);
697 }
698 
699 const struct file_operations hugetlbfs_file_operations = {
700         .read_iter              = hugetlbfs_read_iter,
701         .mmap                   = hugetlbfs_file_mmap,
702         .fsync                  = noop_fsync,
703         .get_unmapped_area      = hugetlb_get_unmapped_area,
704         .llseek         = default_llseek,
705 };
706 
707 static const struct inode_operations hugetlbfs_dir_inode_operations = {
708         .create         = hugetlbfs_create,
709         .lookup         = simple_lookup,
710         .link           = simple_link,
711         .unlink         = simple_unlink,
712         .symlink        = hugetlbfs_symlink,
713         .mkdir          = hugetlbfs_mkdir,
714         .rmdir          = simple_rmdir,
715         .mknod          = hugetlbfs_mknod,
716         .rename         = simple_rename,
717         .setattr        = hugetlbfs_setattr,
718 };
719 
720 static const struct inode_operations hugetlbfs_inode_operations = {
721         .setattr        = hugetlbfs_setattr,
722 };
723 
724 static const struct super_operations hugetlbfs_ops = {
725         .alloc_inode    = hugetlbfs_alloc_inode,
726         .destroy_inode  = hugetlbfs_destroy_inode,
727         .evict_inode    = hugetlbfs_evict_inode,
728         .statfs         = hugetlbfs_statfs,
729         .put_super      = hugetlbfs_put_super,
730         .show_options   = generic_show_options,
731 };
732 
733 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT };
734 
735 /*
736  * Convert size option passed from command line to number of huge pages
737  * in the pool specified by hstate.  Size option could be in bytes
738  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
739  */
740 static long long
741 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
742                                                                 int val_type)
743 {
744         if (val_type == NO_SIZE)
745                 return -1;
746 
747         if (val_type == SIZE_PERCENT) {
748                 size_opt <<= huge_page_shift(h);
749                 size_opt *= h->max_huge_pages;
750                 do_div(size_opt, 100);
751         }
752 
753         size_opt >>= huge_page_shift(h);
754         return size_opt;
755 }
756 
757 static int
758 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
759 {
760         char *p, *rest;
761         substring_t args[MAX_OPT_ARGS];
762         int option;
763         unsigned long long max_size_opt = 0, min_size_opt = 0;
764         int max_val_type = NO_SIZE, min_val_type = NO_SIZE;
765 
766         if (!options)
767                 return 0;
768 
769         while ((p = strsep(&options, ",")) != NULL) {
770                 int token;
771                 if (!*p)
772                         continue;
773 
774                 token = match_token(p, tokens, args);
775                 switch (token) {
776                 case Opt_uid:
777                         if (match_int(&args[0], &option))
778                                 goto bad_val;
779                         pconfig->uid = make_kuid(current_user_ns(), option);
780                         if (!uid_valid(pconfig->uid))
781                                 goto bad_val;
782                         break;
783 
784                 case Opt_gid:
785                         if (match_int(&args[0], &option))
786                                 goto bad_val;
787                         pconfig->gid = make_kgid(current_user_ns(), option);
788                         if (!gid_valid(pconfig->gid))
789                                 goto bad_val;
790                         break;
791 
792                 case Opt_mode:
793                         if (match_octal(&args[0], &option))
794                                 goto bad_val;
795                         pconfig->mode = option & 01777U;
796                         break;
797 
798                 case Opt_size: {
799                         /* memparse() will accept a K/M/G without a digit */
800                         if (!isdigit(*args[0].from))
801                                 goto bad_val;
802                         max_size_opt = memparse(args[0].from, &rest);
803                         max_val_type = SIZE_STD;
804                         if (*rest == '%')
805                                 max_val_type = SIZE_PERCENT;
806                         break;
807                 }
808 
809                 case Opt_nr_inodes:
810                         /* memparse() will accept a K/M/G without a digit */
811                         if (!isdigit(*args[0].from))
812                                 goto bad_val;
813                         pconfig->nr_inodes = memparse(args[0].from, &rest);
814                         break;
815 
816                 case Opt_pagesize: {
817                         unsigned long ps;
818                         ps = memparse(args[0].from, &rest);
819                         pconfig->hstate = size_to_hstate(ps);
820                         if (!pconfig->hstate) {
821                                 pr_err("Unsupported page size %lu MB\n",
822                                         ps >> 20);
823                                 return -EINVAL;
824                         }
825                         break;
826                 }
827 
828                 case Opt_min_size: {
829                         /* memparse() will accept a K/M/G without a digit */
830                         if (!isdigit(*args[0].from))
831                                 goto bad_val;
832                         min_size_opt = memparse(args[0].from, &rest);
833                         min_val_type = SIZE_STD;
834                         if (*rest == '%')
835                                 min_val_type = SIZE_PERCENT;
836                         break;
837                 }
838 
839                 default:
840                         pr_err("Bad mount option: \"%s\"\n", p);
841                         return -EINVAL;
842                         break;
843                 }
844         }
845 
846         /*
847          * Use huge page pool size (in hstate) to convert the size
848          * options to number of huge pages.  If NO_SIZE, -1 is returned.
849          */
850         pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
851                                                 max_size_opt, max_val_type);
852         pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
853                                                 min_size_opt, min_val_type);
854 
855         /*
856          * If max_size was specified, then min_size must be smaller
857          */
858         if (max_val_type > NO_SIZE &&
859             pconfig->min_hpages > pconfig->max_hpages) {
860                 pr_err("minimum size can not be greater than maximum size\n");
861                 return -EINVAL;
862         }
863 
864         return 0;
865 
866 bad_val:
867         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
868         return -EINVAL;
869 }
870 
871 static int
872 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
873 {
874         int ret;
875         struct hugetlbfs_config config;
876         struct hugetlbfs_sb_info *sbinfo;
877 
878         save_mount_options(sb, data);
879 
880         config.max_hpages = -1; /* No limit on size by default */
881         config.nr_inodes = -1; /* No limit on number of inodes by default */
882         config.uid = current_fsuid();
883         config.gid = current_fsgid();
884         config.mode = 0755;
885         config.hstate = &default_hstate;
886         config.min_hpages = -1; /* No default minimum size */
887         ret = hugetlbfs_parse_options(data, &config);
888         if (ret)
889                 return ret;
890 
891         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
892         if (!sbinfo)
893                 return -ENOMEM;
894         sb->s_fs_info = sbinfo;
895         sbinfo->hstate = config.hstate;
896         spin_lock_init(&sbinfo->stat_lock);
897         sbinfo->max_inodes = config.nr_inodes;
898         sbinfo->free_inodes = config.nr_inodes;
899         sbinfo->spool = NULL;
900         /*
901          * Allocate and initialize subpool if maximum or minimum size is
902          * specified.  Any needed reservations (for minimim size) are taken
903          * taken when the subpool is created.
904          */
905         if (config.max_hpages != -1 || config.min_hpages != -1) {
906                 sbinfo->spool = hugepage_new_subpool(config.hstate,
907                                                         config.max_hpages,
908                                                         config.min_hpages);
909                 if (!sbinfo->spool)
910                         goto out_free;
911         }
912         sb->s_maxbytes = MAX_LFS_FILESIZE;
913         sb->s_blocksize = huge_page_size(config.hstate);
914         sb->s_blocksize_bits = huge_page_shift(config.hstate);
915         sb->s_magic = HUGETLBFS_MAGIC;
916         sb->s_op = &hugetlbfs_ops;
917         sb->s_time_gran = 1;
918         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
919         if (!sb->s_root)
920                 goto out_free;
921         return 0;
922 out_free:
923         kfree(sbinfo->spool);
924         kfree(sbinfo);
925         return -ENOMEM;
926 }
927 
928 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
929         int flags, const char *dev_name, void *data)
930 {
931         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
932 }
933 
934 static struct file_system_type hugetlbfs_fs_type = {
935         .name           = "hugetlbfs",
936         .mount          = hugetlbfs_mount,
937         .kill_sb        = kill_litter_super,
938 };
939 MODULE_ALIAS_FS("hugetlbfs");
940 
941 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
942 
943 static int can_do_hugetlb_shm(void)
944 {
945         kgid_t shm_group;
946         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
947         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
948 }
949 
950 static int get_hstate_idx(int page_size_log)
951 {
952         struct hstate *h = hstate_sizelog(page_size_log);
953 
954         if (!h)
955                 return -1;
956         return h - hstates;
957 }
958 
959 static const struct dentry_operations anon_ops = {
960         .d_dname = simple_dname
961 };
962 
963 /*
964  * Note that size should be aligned to proper hugepage size in caller side,
965  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
966  */
967 struct file *hugetlb_file_setup(const char *name, size_t size,
968                                 vm_flags_t acctflag, struct user_struct **user,
969                                 int creat_flags, int page_size_log)
970 {
971         struct file *file = ERR_PTR(-ENOMEM);
972         struct inode *inode;
973         struct path path;
974         struct super_block *sb;
975         struct qstr quick_string;
976         int hstate_idx;
977 
978         hstate_idx = get_hstate_idx(page_size_log);
979         if (hstate_idx < 0)
980                 return ERR_PTR(-ENODEV);
981 
982         *user = NULL;
983         if (!hugetlbfs_vfsmount[hstate_idx])
984                 return ERR_PTR(-ENOENT);
985 
986         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
987                 *user = current_user();
988                 if (user_shm_lock(size, *user)) {
989                         task_lock(current);
990                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
991                                 current->comm, current->pid);
992                         task_unlock(current);
993                 } else {
994                         *user = NULL;
995                         return ERR_PTR(-EPERM);
996                 }
997         }
998 
999         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
1000         quick_string.name = name;
1001         quick_string.len = strlen(quick_string.name);
1002         quick_string.hash = 0;
1003         path.dentry = d_alloc_pseudo(sb, &quick_string);
1004         if (!path.dentry)
1005                 goto out_shm_unlock;
1006 
1007         d_set_d_op(path.dentry, &anon_ops);
1008         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
1009         file = ERR_PTR(-ENOSPC);
1010         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
1011         if (!inode)
1012                 goto out_dentry;
1013         if (creat_flags == HUGETLB_SHMFS_INODE)
1014                 inode->i_flags |= S_PRIVATE;
1015 
1016         file = ERR_PTR(-ENOMEM);
1017         if (hugetlb_reserve_pages(inode, 0,
1018                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1019                         acctflag))
1020                 goto out_inode;
1021 
1022         d_instantiate(path.dentry, inode);
1023         inode->i_size = size;
1024         clear_nlink(inode);
1025 
1026         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1027                         &hugetlbfs_file_operations);
1028         if (IS_ERR(file))
1029                 goto out_dentry; /* inode is already attached */
1030 
1031         return file;
1032 
1033 out_inode:
1034         iput(inode);
1035 out_dentry:
1036         path_put(&path);
1037 out_shm_unlock:
1038         if (*user) {
1039                 user_shm_unlock(size, *user);
1040                 *user = NULL;
1041         }
1042         return file;
1043 }
1044 
1045 static int __init init_hugetlbfs_fs(void)
1046 {
1047         struct hstate *h;
1048         int error;
1049         int i;
1050 
1051         if (!hugepages_supported()) {
1052                 pr_info("disabling because there are no supported hugepage sizes\n");
1053                 return -ENOTSUPP;
1054         }
1055 
1056         error = -ENOMEM;
1057         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1058                                         sizeof(struct hugetlbfs_inode_info),
1059                                         0, 0, init_once);
1060         if (hugetlbfs_inode_cachep == NULL)
1061                 goto out2;
1062 
1063         error = register_filesystem(&hugetlbfs_fs_type);
1064         if (error)
1065                 goto out;
1066 
1067         i = 0;
1068         for_each_hstate(h) {
1069                 char buf[50];
1070                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1071 
1072                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1073                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1074                                                         buf);
1075 
1076                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1077                         pr_err("Cannot mount internal hugetlbfs for "
1078                                 "page size %uK", ps_kb);
1079                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1080                         hugetlbfs_vfsmount[i] = NULL;
1081                 }
1082                 i++;
1083         }
1084         /* Non default hstates are optional */
1085         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1086                 return 0;
1087 
1088  out:
1089         kmem_cache_destroy(hugetlbfs_inode_cachep);
1090  out2:
1091         return error;
1092 }
1093 
1094 static void __exit exit_hugetlbfs_fs(void)
1095 {
1096         struct hstate *h;
1097         int i;
1098 
1099 
1100         /*
1101          * Make sure all delayed rcu free inodes are flushed before we
1102          * destroy cache.
1103          */
1104         rcu_barrier();
1105         kmem_cache_destroy(hugetlbfs_inode_cachep);
1106         i = 0;
1107         for_each_hstate(h)
1108                 kern_unmount(hugetlbfs_vfsmount[i++]);
1109         unregister_filesystem(&hugetlbfs_fs_type);
1110 }
1111 
1112 module_init(init_hugetlbfs_fs)
1113 module_exit(exit_hugetlbfs_fs)
1114 
1115 MODULE_LICENSE("GPL");
1116 

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