Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

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 #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         struct resv_map *resv_map;
370 
371         truncate_hugepages(inode, 0);
372         resv_map = (struct resv_map *)inode->i_mapping->private_data;
373         /* root inode doesn't have the resv_map, so we should check it */
374         if (resv_map)
375                 resv_map_release(&resv_map->refs);
376         clear_inode(inode);
377 }
378 
379 static inline void
380 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
381 {
382         struct vm_area_struct *vma;
383 
384         vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
385                 unsigned long v_offset;
386 
387                 /*
388                  * Can the expression below overflow on 32-bit arches?
389                  * No, because the interval tree returns us only those vmas
390                  * which overlap the truncated area starting at pgoff,
391                  * and no vma on a 32-bit arch can span beyond the 4GB.
392                  */
393                 if (vma->vm_pgoff < pgoff)
394                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
395                 else
396                         v_offset = 0;
397 
398                 unmap_hugepage_range(vma, vma->vm_start + v_offset,
399                                      vma->vm_end, NULL);
400         }
401 }
402 
403 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
404 {
405         pgoff_t pgoff;
406         struct address_space *mapping = inode->i_mapping;
407         struct hstate *h = hstate_inode(inode);
408 
409         BUG_ON(offset & ~huge_page_mask(h));
410         pgoff = offset >> PAGE_SHIFT;
411 
412         i_size_write(inode, offset);
413         mutex_lock(&mapping->i_mmap_mutex);
414         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
415                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
416         mutex_unlock(&mapping->i_mmap_mutex);
417         truncate_hugepages(inode, offset);
418         return 0;
419 }
420 
421 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
422 {
423         struct inode *inode = dentry->d_inode;
424         struct hstate *h = hstate_inode(inode);
425         int error;
426         unsigned int ia_valid = attr->ia_valid;
427 
428         BUG_ON(!inode);
429 
430         error = inode_change_ok(inode, attr);
431         if (error)
432                 return error;
433 
434         if (ia_valid & ATTR_SIZE) {
435                 error = -EINVAL;
436                 if (attr->ia_size & ~huge_page_mask(h))
437                         return -EINVAL;
438                 error = hugetlb_vmtruncate(inode, attr->ia_size);
439                 if (error)
440                         return error;
441         }
442 
443         setattr_copy(inode, attr);
444         mark_inode_dirty(inode);
445         return 0;
446 }
447 
448 static struct inode *hugetlbfs_get_root(struct super_block *sb,
449                                         struct hugetlbfs_config *config)
450 {
451         struct inode *inode;
452 
453         inode = new_inode(sb);
454         if (inode) {
455                 struct hugetlbfs_inode_info *info;
456                 inode->i_ino = get_next_ino();
457                 inode->i_mode = S_IFDIR | config->mode;
458                 inode->i_uid = config->uid;
459                 inode->i_gid = config->gid;
460                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
461                 info = HUGETLBFS_I(inode);
462                 mpol_shared_policy_init(&info->policy, NULL);
463                 inode->i_op = &hugetlbfs_dir_inode_operations;
464                 inode->i_fop = &simple_dir_operations;
465                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
466                 inc_nlink(inode);
467                 lockdep_annotate_inode_mutex_key(inode);
468         }
469         return inode;
470 }
471 
472 /*
473  * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never
474  * be taken from reclaim -- unlike regular filesystems. This needs an
475  * annotation because huge_pmd_share() does an allocation under
476  * i_mmap_mutex.
477  */
478 struct lock_class_key hugetlbfs_i_mmap_mutex_key;
479 
480 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
481                                         struct inode *dir,
482                                         umode_t mode, dev_t dev)
483 {
484         struct inode *inode;
485         struct resv_map *resv_map;
486 
487         resv_map = resv_map_alloc();
488         if (!resv_map)
489                 return NULL;
490 
491         inode = new_inode(sb);
492         if (inode) {
493                 struct hugetlbfs_inode_info *info;
494                 inode->i_ino = get_next_ino();
495                 inode_init_owner(inode, dir, mode);
496                 lockdep_set_class(&inode->i_mapping->i_mmap_mutex,
497                                 &hugetlbfs_i_mmap_mutex_key);
498                 inode->i_mapping->a_ops = &hugetlbfs_aops;
499                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
500                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
501                 inode->i_mapping->private_data = resv_map;
502                 info = HUGETLBFS_I(inode);
503                 /*
504                  * The policy is initialized here even if we are creating a
505                  * private inode because initialization simply creates an
506                  * an empty rb tree and calls spin_lock_init(), later when we
507                  * call mpol_free_shared_policy() it will just return because
508                  * the rb tree will still be empty.
509                  */
510                 mpol_shared_policy_init(&info->policy, NULL);
511                 switch (mode & S_IFMT) {
512                 default:
513                         init_special_inode(inode, mode, dev);
514                         break;
515                 case S_IFREG:
516                         inode->i_op = &hugetlbfs_inode_operations;
517                         inode->i_fop = &hugetlbfs_file_operations;
518                         break;
519                 case S_IFDIR:
520                         inode->i_op = &hugetlbfs_dir_inode_operations;
521                         inode->i_fop = &simple_dir_operations;
522 
523                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
524                         inc_nlink(inode);
525                         break;
526                 case S_IFLNK:
527                         inode->i_op = &page_symlink_inode_operations;
528                         break;
529                 }
530                 lockdep_annotate_inode_mutex_key(inode);
531         } else
532                 kref_put(&resv_map->refs, resv_map_release);
533 
534         return inode;
535 }
536 
537 /*
538  * File creation. Allocate an inode, and we're done..
539  */
540 static int hugetlbfs_mknod(struct inode *dir,
541                         struct dentry *dentry, umode_t mode, dev_t dev)
542 {
543         struct inode *inode;
544         int error = -ENOSPC;
545 
546         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
547         if (inode) {
548                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
549                 d_instantiate(dentry, inode);
550                 dget(dentry);   /* Extra count - pin the dentry in core */
551                 error = 0;
552         }
553         return error;
554 }
555 
556 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
557 {
558         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
559         if (!retval)
560                 inc_nlink(dir);
561         return retval;
562 }
563 
564 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
565 {
566         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
567 }
568 
569 static int hugetlbfs_symlink(struct inode *dir,
570                         struct dentry *dentry, const char *symname)
571 {
572         struct inode *inode;
573         int error = -ENOSPC;
574 
575         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
576         if (inode) {
577                 int l = strlen(symname)+1;
578                 error = page_symlink(inode, symname, l);
579                 if (!error) {
580                         d_instantiate(dentry, inode);
581                         dget(dentry);
582                 } else
583                         iput(inode);
584         }
585         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
586 
587         return error;
588 }
589 
590 /*
591  * mark the head page dirty
592  */
593 static int hugetlbfs_set_page_dirty(struct page *page)
594 {
595         struct page *head = compound_head(page);
596 
597         SetPageDirty(head);
598         return 0;
599 }
600 
601 static int hugetlbfs_migrate_page(struct address_space *mapping,
602                                 struct page *newpage, struct page *page,
603                                 enum migrate_mode mode)
604 {
605         int rc;
606 
607         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
608         if (rc != MIGRATEPAGE_SUCCESS)
609                 return rc;
610         migrate_page_copy(newpage, page);
611 
612         return MIGRATEPAGE_SUCCESS;
613 }
614 
615 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
616 {
617         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
618         struct hstate *h = hstate_inode(dentry->d_inode);
619 
620         buf->f_type = HUGETLBFS_MAGIC;
621         buf->f_bsize = huge_page_size(h);
622         if (sbinfo) {
623                 spin_lock(&sbinfo->stat_lock);
624                 /* If no limits set, just report 0 for max/free/used
625                  * blocks, like simple_statfs() */
626                 if (sbinfo->spool) {
627                         long free_pages;
628 
629                         spin_lock(&sbinfo->spool->lock);
630                         buf->f_blocks = sbinfo->spool->max_hpages;
631                         free_pages = sbinfo->spool->max_hpages
632                                 - sbinfo->spool->used_hpages;
633                         buf->f_bavail = buf->f_bfree = free_pages;
634                         spin_unlock(&sbinfo->spool->lock);
635                         buf->f_files = sbinfo->max_inodes;
636                         buf->f_ffree = sbinfo->free_inodes;
637                 }
638                 spin_unlock(&sbinfo->stat_lock);
639         }
640         buf->f_namelen = NAME_MAX;
641         return 0;
642 }
643 
644 static void hugetlbfs_put_super(struct super_block *sb)
645 {
646         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
647 
648         if (sbi) {
649                 sb->s_fs_info = NULL;
650 
651                 if (sbi->spool)
652                         hugepage_put_subpool(sbi->spool);
653 
654                 kfree(sbi);
655         }
656 }
657 
658 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
659 {
660         if (sbinfo->free_inodes >= 0) {
661                 spin_lock(&sbinfo->stat_lock);
662                 if (unlikely(!sbinfo->free_inodes)) {
663                         spin_unlock(&sbinfo->stat_lock);
664                         return 0;
665                 }
666                 sbinfo->free_inodes--;
667                 spin_unlock(&sbinfo->stat_lock);
668         }
669 
670         return 1;
671 }
672 
673 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
674 {
675         if (sbinfo->free_inodes >= 0) {
676                 spin_lock(&sbinfo->stat_lock);
677                 sbinfo->free_inodes++;
678                 spin_unlock(&sbinfo->stat_lock);
679         }
680 }
681 
682 
683 static struct kmem_cache *hugetlbfs_inode_cachep;
684 
685 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
686 {
687         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
688         struct hugetlbfs_inode_info *p;
689 
690         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
691                 return NULL;
692         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
693         if (unlikely(!p)) {
694                 hugetlbfs_inc_free_inodes(sbinfo);
695                 return NULL;
696         }
697         return &p->vfs_inode;
698 }
699 
700 static void hugetlbfs_i_callback(struct rcu_head *head)
701 {
702         struct inode *inode = container_of(head, struct inode, i_rcu);
703         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
704 }
705 
706 static void hugetlbfs_destroy_inode(struct inode *inode)
707 {
708         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
709         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
710         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
711 }
712 
713 static const struct address_space_operations hugetlbfs_aops = {
714         .write_begin    = hugetlbfs_write_begin,
715         .write_end      = hugetlbfs_write_end,
716         .set_page_dirty = hugetlbfs_set_page_dirty,
717         .migratepage    = hugetlbfs_migrate_page,
718 };
719 
720 
721 static void init_once(void *foo)
722 {
723         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
724 
725         inode_init_once(&ei->vfs_inode);
726 }
727 
728 const struct file_operations hugetlbfs_file_operations = {
729         .read                   = hugetlbfs_read,
730         .mmap                   = hugetlbfs_file_mmap,
731         .fsync                  = noop_fsync,
732         .get_unmapped_area      = hugetlb_get_unmapped_area,
733         .llseek         = default_llseek,
734 };
735 
736 static const struct inode_operations hugetlbfs_dir_inode_operations = {
737         .create         = hugetlbfs_create,
738         .lookup         = simple_lookup,
739         .link           = simple_link,
740         .unlink         = simple_unlink,
741         .symlink        = hugetlbfs_symlink,
742         .mkdir          = hugetlbfs_mkdir,
743         .rmdir          = simple_rmdir,
744         .mknod          = hugetlbfs_mknod,
745         .rename         = simple_rename,
746         .setattr        = hugetlbfs_setattr,
747 };
748 
749 static const struct inode_operations hugetlbfs_inode_operations = {
750         .setattr        = hugetlbfs_setattr,
751 };
752 
753 static const struct super_operations hugetlbfs_ops = {
754         .alloc_inode    = hugetlbfs_alloc_inode,
755         .destroy_inode  = hugetlbfs_destroy_inode,
756         .evict_inode    = hugetlbfs_evict_inode,
757         .statfs         = hugetlbfs_statfs,
758         .put_super      = hugetlbfs_put_super,
759         .show_options   = generic_show_options,
760 };
761 
762 static int
763 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
764 {
765         char *p, *rest;
766         substring_t args[MAX_OPT_ARGS];
767         int option;
768         unsigned long long size = 0;
769         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
770 
771         if (!options)
772                 return 0;
773 
774         while ((p = strsep(&options, ",")) != NULL) {
775                 int token;
776                 if (!*p)
777                         continue;
778 
779                 token = match_token(p, tokens, args);
780                 switch (token) {
781                 case Opt_uid:
782                         if (match_int(&args[0], &option))
783                                 goto bad_val;
784                         pconfig->uid = make_kuid(current_user_ns(), option);
785                         if (!uid_valid(pconfig->uid))
786                                 goto bad_val;
787                         break;
788 
789                 case Opt_gid:
790                         if (match_int(&args[0], &option))
791                                 goto bad_val;
792                         pconfig->gid = make_kgid(current_user_ns(), option);
793                         if (!gid_valid(pconfig->gid))
794                                 goto bad_val;
795                         break;
796 
797                 case Opt_mode:
798                         if (match_octal(&args[0], &option))
799                                 goto bad_val;
800                         pconfig->mode = option & 01777U;
801                         break;
802 
803                 case Opt_size: {
804                         /* memparse() will accept a K/M/G without a digit */
805                         if (!isdigit(*args[0].from))
806                                 goto bad_val;
807                         size = memparse(args[0].from, &rest);
808                         setsize = SIZE_STD;
809                         if (*rest == '%')
810                                 setsize = SIZE_PERCENT;
811                         break;
812                 }
813 
814                 case Opt_nr_inodes:
815                         /* memparse() will accept a K/M/G without a digit */
816                         if (!isdigit(*args[0].from))
817                                 goto bad_val;
818                         pconfig->nr_inodes = memparse(args[0].from, &rest);
819                         break;
820 
821                 case Opt_pagesize: {
822                         unsigned long ps;
823                         ps = memparse(args[0].from, &rest);
824                         pconfig->hstate = size_to_hstate(ps);
825                         if (!pconfig->hstate) {
826                                 printk(KERN_ERR
827                                 "hugetlbfs: Unsupported page size %lu MB\n",
828                                         ps >> 20);
829                                 return -EINVAL;
830                         }
831                         break;
832                 }
833 
834                 default:
835                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
836                                  p);
837                         return -EINVAL;
838                         break;
839                 }
840         }
841 
842         /* Do size after hstate is set up */
843         if (setsize > NO_SIZE) {
844                 struct hstate *h = pconfig->hstate;
845                 if (setsize == SIZE_PERCENT) {
846                         size <<= huge_page_shift(h);
847                         size *= h->max_huge_pages;
848                         do_div(size, 100);
849                 }
850                 pconfig->nr_blocks = (size >> huge_page_shift(h));
851         }
852 
853         return 0;
854 
855 bad_val:
856         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
857                args[0].from, p);
858         return -EINVAL;
859 }
860 
861 static int
862 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
863 {
864         int ret;
865         struct hugetlbfs_config config;
866         struct hugetlbfs_sb_info *sbinfo;
867 
868         save_mount_options(sb, data);
869 
870         config.nr_blocks = -1; /* No limit on size by default */
871         config.nr_inodes = -1; /* No limit on number of inodes by default */
872         config.uid = current_fsuid();
873         config.gid = current_fsgid();
874         config.mode = 0755;
875         config.hstate = &default_hstate;
876         ret = hugetlbfs_parse_options(data, &config);
877         if (ret)
878                 return ret;
879 
880         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
881         if (!sbinfo)
882                 return -ENOMEM;
883         sb->s_fs_info = sbinfo;
884         sbinfo->hstate = config.hstate;
885         spin_lock_init(&sbinfo->stat_lock);
886         sbinfo->max_inodes = config.nr_inodes;
887         sbinfo->free_inodes = config.nr_inodes;
888         sbinfo->spool = NULL;
889         if (config.nr_blocks != -1) {
890                 sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
891                 if (!sbinfo->spool)
892                         goto out_free;
893         }
894         sb->s_maxbytes = MAX_LFS_FILESIZE;
895         sb->s_blocksize = huge_page_size(config.hstate);
896         sb->s_blocksize_bits = huge_page_shift(config.hstate);
897         sb->s_magic = HUGETLBFS_MAGIC;
898         sb->s_op = &hugetlbfs_ops;
899         sb->s_time_gran = 1;
900         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
901         if (!sb->s_root)
902                 goto out_free;
903         return 0;
904 out_free:
905         if (sbinfo->spool)
906                 kfree(sbinfo->spool);
907         kfree(sbinfo);
908         return -ENOMEM;
909 }
910 
911 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
912         int flags, const char *dev_name, void *data)
913 {
914         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
915 }
916 
917 static struct file_system_type hugetlbfs_fs_type = {
918         .name           = "hugetlbfs",
919         .mount          = hugetlbfs_mount,
920         .kill_sb        = kill_litter_super,
921 };
922 MODULE_ALIAS_FS("hugetlbfs");
923 
924 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
925 
926 static int can_do_hugetlb_shm(void)
927 {
928         kgid_t shm_group;
929         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
930         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
931 }
932 
933 static int get_hstate_idx(int page_size_log)
934 {
935         struct hstate *h = hstate_sizelog(page_size_log);
936 
937         if (!h)
938                 return -1;
939         return h - hstates;
940 }
941 
942 static struct dentry_operations anon_ops = {
943         .d_dname = simple_dname
944 };
945 
946 /*
947  * Note that size should be aligned to proper hugepage size in caller side,
948  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
949  */
950 struct file *hugetlb_file_setup(const char *name, size_t size,
951                                 vm_flags_t acctflag, struct user_struct **user,
952                                 int creat_flags, int page_size_log)
953 {
954         struct file *file = ERR_PTR(-ENOMEM);
955         struct inode *inode;
956         struct path path;
957         struct super_block *sb;
958         struct qstr quick_string;
959         int hstate_idx;
960 
961         hstate_idx = get_hstate_idx(page_size_log);
962         if (hstate_idx < 0)
963                 return ERR_PTR(-ENODEV);
964 
965         *user = NULL;
966         if (!hugetlbfs_vfsmount[hstate_idx])
967                 return ERR_PTR(-ENOENT);
968 
969         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
970                 *user = current_user();
971                 if (user_shm_lock(size, *user)) {
972                         task_lock(current);
973                         printk_once(KERN_WARNING
974                                 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
975                                 current->comm, current->pid);
976                         task_unlock(current);
977                 } else {
978                         *user = NULL;
979                         return ERR_PTR(-EPERM);
980                 }
981         }
982 
983         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
984         quick_string.name = name;
985         quick_string.len = strlen(quick_string.name);
986         quick_string.hash = 0;
987         path.dentry = d_alloc_pseudo(sb, &quick_string);
988         if (!path.dentry)
989                 goto out_shm_unlock;
990 
991         d_set_d_op(path.dentry, &anon_ops);
992         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
993         file = ERR_PTR(-ENOSPC);
994         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
995         if (!inode)
996                 goto out_dentry;
997 
998         file = ERR_PTR(-ENOMEM);
999         if (hugetlb_reserve_pages(inode, 0,
1000                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1001                         acctflag))
1002                 goto out_inode;
1003 
1004         d_instantiate(path.dentry, inode);
1005         inode->i_size = size;
1006         clear_nlink(inode);
1007 
1008         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1009                         &hugetlbfs_file_operations);
1010         if (IS_ERR(file))
1011                 goto out_dentry; /* inode is already attached */
1012 
1013         return file;
1014 
1015 out_inode:
1016         iput(inode);
1017 out_dentry:
1018         path_put(&path);
1019 out_shm_unlock:
1020         if (*user) {
1021                 user_shm_unlock(size, *user);
1022                 *user = NULL;
1023         }
1024         return file;
1025 }
1026 
1027 static int __init init_hugetlbfs_fs(void)
1028 {
1029         struct hstate *h;
1030         int error;
1031         int i;
1032 
1033         if (!hugepages_supported()) {
1034                 pr_info("hugetlbfs: disabling because there are no supported hugepage sizes\n");
1035                 return -ENOTSUPP;
1036         }
1037 
1038         error = bdi_init(&hugetlbfs_backing_dev_info);
1039         if (error)
1040                 return error;
1041 
1042         error = -ENOMEM;
1043         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1044                                         sizeof(struct hugetlbfs_inode_info),
1045                                         0, 0, init_once);
1046         if (hugetlbfs_inode_cachep == NULL)
1047                 goto out2;
1048 
1049         error = register_filesystem(&hugetlbfs_fs_type);
1050         if (error)
1051                 goto out;
1052 
1053         i = 0;
1054         for_each_hstate(h) {
1055                 char buf[50];
1056                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1057 
1058                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1059                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1060                                                         buf);
1061 
1062                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1063                         pr_err("hugetlb: Cannot mount internal hugetlbfs for "
1064                                 "page size %uK", ps_kb);
1065                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1066                         hugetlbfs_vfsmount[i] = NULL;
1067                 }
1068                 i++;
1069         }
1070         /* Non default hstates are optional */
1071         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1072                 return 0;
1073 
1074  out:
1075         kmem_cache_destroy(hugetlbfs_inode_cachep);
1076  out2:
1077         bdi_destroy(&hugetlbfs_backing_dev_info);
1078         return error;
1079 }
1080 
1081 static void __exit exit_hugetlbfs_fs(void)
1082 {
1083         struct hstate *h;
1084         int i;
1085 
1086 
1087         /*
1088          * Make sure all delayed rcu free inodes are flushed before we
1089          * destroy cache.
1090          */
1091         rcu_barrier();
1092         kmem_cache_destroy(hugetlbfs_inode_cachep);
1093         i = 0;
1094         for_each_hstate(h)
1095                 kern_unmount(hugetlbfs_vfsmount[i++]);
1096         unregister_filesystem(&hugetlbfs_fs_type);
1097         bdi_destroy(&hugetlbfs_backing_dev_info);
1098 }
1099 
1100 module_init(init_hugetlbfs_fs)
1101 module_exit(exit_hugetlbfs_fs)
1102 
1103 MODULE_LICENSE("GPL");
1104 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us