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TOMOYO Linux Cross Reference
Linux/fs/hugetlbfs/inode.c

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

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