mm: compaction: introduce sync-light migration for use by compaction
[linux-2.6.git] / fs / hugetlbfs / inode.c
1 /*
2  * hugetlbpage-backed filesystem.  Based on ramfs.
3  *
4  * William Irwin, 2002
5  *
6  * Copyright (C) 2002 Linus Torvalds.
7  */
8
9 #include <linux/module.h>
10 #include <linux/thread_info.h>
11 #include <asm/current.h>
12 #include <linux/sched.h>                /* remove ASAP */
13 #include <linux/fs.h>
14 #include <linux/mount.h>
15 #include <linux/file.h>
16 #include <linux/kernel.h>
17 #include <linux/writeback.h>
18 #include <linux/pagemap.h>
19 #include <linux/highmem.h>
20 #include <linux/init.h>
21 #include <linux/string.h>
22 #include <linux/capability.h>
23 #include <linux/ctype.h>
24 #include <linux/backing-dev.h>
25 #include <linux/hugetlb.h>
26 #include <linux/pagevec.h>
27 #include <linux/parser.h>
28 #include <linux/mman.h>
29 #include <linux/slab.h>
30 #include <linux/dnotify.h>
31 #include <linux/statfs.h>
32 #include <linux/security.h>
33 #include <linux/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 static struct backing_dev_info hugetlbfs_backing_dev_info = {
45         .name           = "hugetlbfs",
46         .ra_pages       = 0,    /* No readahead */
47         .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
48 };
49
50 int sysctl_hugetlb_shm_group;
51
52 enum {
53         Opt_size, Opt_nr_inodes,
54         Opt_mode, Opt_uid, Opt_gid,
55         Opt_pagesize,
56         Opt_err,
57 };
58
59 static const match_table_t tokens = {
60         {Opt_size,      "size=%s"},
61         {Opt_nr_inodes, "nr_inodes=%s"},
62         {Opt_mode,      "mode=%o"},
63         {Opt_uid,       "uid=%u"},
64         {Opt_gid,       "gid=%u"},
65         {Opt_pagesize,  "pagesize=%s"},
66         {Opt_err,       NULL},
67 };
68
69 static void huge_pagevec_release(struct pagevec *pvec)
70 {
71         int i;
72
73         for (i = 0; i < pagevec_count(pvec); ++i)
74                 put_page(pvec->pages[i]);
75
76         pagevec_reinit(pvec);
77 }
78
79 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
80 {
81         struct inode *inode = file->f_path.dentry->d_inode;
82         loff_t len, vma_len;
83         int ret;
84         struct hstate *h = hstate_file(file);
85
86         /*
87          * vma address alignment (but not the pgoff alignment) has
88          * already been checked by prepare_hugepage_range.  If you add
89          * any error returns here, do so after setting VM_HUGETLB, so
90          * is_vm_hugetlb_page tests below unmap_region go the right
91          * way when do_mmap_pgoff unwinds (may be important on powerpc
92          * and ia64).
93          */
94         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
95         vma->vm_ops = &hugetlb_vm_ops;
96
97         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
98                 return -EINVAL;
99
100         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
101
102         mutex_lock(&inode->i_mutex);
103         file_accessed(file);
104
105         ret = -ENOMEM;
106         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
107
108         if (hugetlb_reserve_pages(inode,
109                                 vma->vm_pgoff >> huge_page_order(h),
110                                 len >> huge_page_shift(h), vma,
111                                 vma->vm_flags))
112                 goto out;
113
114         ret = 0;
115         hugetlb_prefault_arch_hook(vma->vm_mm);
116         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
117                 inode->i_size = len;
118 out:
119         mutex_unlock(&inode->i_mutex);
120
121         return ret;
122 }
123
124 /*
125  * Called under down_write(mmap_sem).
126  */
127
128 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
129 static unsigned long
130 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
131                 unsigned long len, unsigned long pgoff, unsigned long flags)
132 {
133         struct mm_struct *mm = current->mm;
134         struct vm_area_struct *vma;
135         unsigned long start_addr;
136         struct hstate *h = hstate_file(file);
137
138         if (len & ~huge_page_mask(h))
139                 return -EINVAL;
140         if (len > TASK_SIZE)
141                 return -ENOMEM;
142
143         if (flags & MAP_FIXED) {
144                 if (prepare_hugepage_range(file, addr, len))
145                         return -EINVAL;
146                 return addr;
147         }
148
149         if (addr) {
150                 addr = ALIGN(addr, huge_page_size(h));
151                 vma = find_vma(mm, addr);
152                 if (TASK_SIZE - len >= addr &&
153                     (!vma || addr + len <= vma->vm_start))
154                         return addr;
155         }
156
157         start_addr = mm->free_area_cache;
158
159         if (len <= mm->cached_hole_size)
160                 start_addr = TASK_UNMAPPED_BASE;
161
162 full_search:
163         addr = ALIGN(start_addr, huge_page_size(h));
164
165         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
166                 /* At this point:  (!vma || addr < vma->vm_end). */
167                 if (TASK_SIZE - len < addr) {
168                         /*
169                          * Start a new search - just in case we missed
170                          * some holes.
171                          */
172                         if (start_addr != TASK_UNMAPPED_BASE) {
173                                 start_addr = TASK_UNMAPPED_BASE;
174                                 goto full_search;
175                         }
176                         return -ENOMEM;
177                 }
178
179                 if (!vma || addr + len <= vma->vm_start)
180                         return addr;
181                 addr = ALIGN(vma->vm_end, huge_page_size(h));
182         }
183 }
184 #endif
185
186 static int
187 hugetlbfs_read_actor(struct page *page, unsigned long offset,
188                         char __user *buf, unsigned long count,
189                         unsigned long size)
190 {
191         char *kaddr;
192         unsigned long left, copied = 0;
193         int i, chunksize;
194
195         if (size > count)
196                 size = count;
197
198         /* Find which 4k chunk and offset with in that chunk */
199         i = offset >> PAGE_CACHE_SHIFT;
200         offset = offset & ~PAGE_CACHE_MASK;
201
202         while (size) {
203                 chunksize = PAGE_CACHE_SIZE;
204                 if (offset)
205                         chunksize -= offset;
206                 if (chunksize > size)
207                         chunksize = size;
208                 kaddr = kmap(&page[i]);
209                 left = __copy_to_user(buf, kaddr + offset, chunksize);
210                 kunmap(&page[i]);
211                 if (left) {
212                         copied += (chunksize - left);
213                         break;
214                 }
215                 offset = 0;
216                 size -= chunksize;
217                 buf += chunksize;
218                 copied += chunksize;
219                 i++;
220         }
221         return copied ? copied : -EFAULT;
222 }
223
224 /*
225  * Support for read() - Find the page attached to f_mapping and copy out the
226  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
227  * since it has PAGE_CACHE_SIZE assumptions.
228  */
229 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
230                               size_t len, loff_t *ppos)
231 {
232         struct hstate *h = hstate_file(filp);
233         struct address_space *mapping = filp->f_mapping;
234         struct inode *inode = mapping->host;
235         unsigned long index = *ppos >> huge_page_shift(h);
236         unsigned long offset = *ppos & ~huge_page_mask(h);
237         unsigned long end_index;
238         loff_t isize;
239         ssize_t retval = 0;
240
241         mutex_lock(&inode->i_mutex);
242
243         /* validate length */
244         if (len == 0)
245                 goto out;
246
247         isize = i_size_read(inode);
248         if (!isize)
249                 goto out;
250
251         end_index = (isize - 1) >> huge_page_shift(h);
252         for (;;) {
253                 struct page *page;
254                 unsigned long nr, ret;
255                 int ra;
256
257                 /* nr is the maximum number of bytes to copy from this page */
258                 nr = huge_page_size(h);
259                 if (index >= end_index) {
260                         if (index > end_index)
261                                 goto out;
262                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
263                         if (nr <= offset) {
264                                 goto out;
265                         }
266                 }
267                 nr = nr - offset;
268
269                 /* Find the page */
270                 page = find_get_page(mapping, index);
271                 if (unlikely(page == NULL)) {
272                         /*
273                          * We have a HOLE, zero out the user-buffer for the
274                          * length of the hole or request.
275                          */
276                         ret = len < nr ? len : nr;
277                         if (clear_user(buf, ret))
278                                 ra = -EFAULT;
279                         else
280                                 ra = 0;
281                 } else {
282                         /*
283                          * We have the page, copy it to user space buffer.
284                          */
285                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
286                         ret = ra;
287                 }
288                 if (ra < 0) {
289                         if (retval == 0)
290                                 retval = ra;
291                         if (page)
292                                 page_cache_release(page);
293                         goto out;
294                 }
295
296                 offset += ret;
297                 retval += ret;
298                 len -= ret;
299                 index += offset >> huge_page_shift(h);
300                 offset &= ~huge_page_mask(h);
301
302                 if (page)
303                         page_cache_release(page);
304
305                 /* short read or no more work */
306                 if ((ret != nr) || (len == 0))
307                         break;
308         }
309 out:
310         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
311         mutex_unlock(&inode->i_mutex);
312         return retval;
313 }
314
315 static int hugetlbfs_write_begin(struct file *file,
316                         struct address_space *mapping,
317                         loff_t pos, unsigned len, unsigned flags,
318                         struct page **pagep, void **fsdata)
319 {
320         return -EINVAL;
321 }
322
323 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
324                         loff_t pos, unsigned len, unsigned copied,
325                         struct page *page, void *fsdata)
326 {
327         BUG();
328         return -EINVAL;
329 }
330
331 static void truncate_huge_page(struct page *page)
332 {
333         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
334         ClearPageUptodate(page);
335         delete_from_page_cache(page);
336 }
337
338 static void truncate_hugepages(struct inode *inode, loff_t lstart)
339 {
340         struct hstate *h = hstate_inode(inode);
341         struct address_space *mapping = &inode->i_data;
342         const pgoff_t start = lstart >> huge_page_shift(h);
343         struct pagevec pvec;
344         pgoff_t next;
345         int i, freed = 0;
346
347         pagevec_init(&pvec, 0);
348         next = start;
349         while (1) {
350                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
351                         if (next == start)
352                                 break;
353                         next = start;
354                         continue;
355                 }
356
357                 for (i = 0; i < pagevec_count(&pvec); ++i) {
358                         struct page *page = pvec.pages[i];
359
360                         lock_page(page);
361                         if (page->index > next)
362                                 next = page->index;
363                         ++next;
364                         truncate_huge_page(page);
365                         unlock_page(page);
366                         freed++;
367                 }
368                 huge_pagevec_release(&pvec);
369         }
370         BUG_ON(!lstart && mapping->nrpages);
371         hugetlb_unreserve_pages(inode, start, freed);
372 }
373
374 static void hugetlbfs_evict_inode(struct inode *inode)
375 {
376         truncate_hugepages(inode, 0);
377         end_writeback(inode);
378 }
379
380 static inline void
381 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
382 {
383         struct vm_area_struct *vma;
384         struct prio_tree_iter iter;
385
386         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
387                 unsigned long v_offset;
388
389                 /*
390                  * Can the expression below overflow on 32-bit arches?
391                  * No, because the prio_tree returns us only those vmas
392                  * which overlap the truncated area starting at pgoff,
393                  * and no vma on a 32-bit arch can span beyond the 4GB.
394                  */
395                 if (vma->vm_pgoff < pgoff)
396                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
397                 else
398                         v_offset = 0;
399
400                 __unmap_hugepage_range(vma,
401                                 vma->vm_start + v_offset, vma->vm_end, NULL);
402         }
403 }
404
405 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
406 {
407         pgoff_t pgoff;
408         struct address_space *mapping = inode->i_mapping;
409         struct hstate *h = hstate_inode(inode);
410
411         BUG_ON(offset & ~huge_page_mask(h));
412         pgoff = offset >> PAGE_SHIFT;
413
414         i_size_write(inode, offset);
415         mutex_lock(&mapping->i_mmap_mutex);
416         if (!prio_tree_empty(&mapping->i_mmap))
417                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
418         mutex_unlock(&mapping->i_mmap_mutex);
419         truncate_hugepages(inode, offset);
420         return 0;
421 }
422
423 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
424 {
425         struct inode *inode = dentry->d_inode;
426         struct hstate *h = hstate_inode(inode);
427         int error;
428         unsigned int ia_valid = attr->ia_valid;
429
430         BUG_ON(!inode);
431
432         error = inode_change_ok(inode, attr);
433         if (error)
434                 return error;
435
436         if (ia_valid & ATTR_SIZE) {
437                 error = -EINVAL;
438                 if (attr->ia_size & ~huge_page_mask(h))
439                         return -EINVAL;
440                 error = hugetlb_vmtruncate(inode, attr->ia_size);
441                 if (error)
442                         return error;
443         }
444
445         setattr_copy(inode, attr);
446         mark_inode_dirty(inode);
447         return 0;
448 }
449
450 static struct inode *hugetlbfs_get_root(struct super_block *sb,
451                                         struct hugetlbfs_config *config)
452 {
453         struct inode *inode;
454
455         inode = new_inode(sb);
456         if (inode) {
457                 struct hugetlbfs_inode_info *info;
458                 inode->i_ino = get_next_ino();
459                 inode->i_mode = S_IFDIR | config->mode;
460                 inode->i_uid = config->uid;
461                 inode->i_gid = config->gid;
462                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
463                 info = HUGETLBFS_I(inode);
464                 mpol_shared_policy_init(&info->policy, NULL);
465                 inode->i_op = &hugetlbfs_dir_inode_operations;
466                 inode->i_fop = &simple_dir_operations;
467                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
468                 inc_nlink(inode);
469         }
470         return inode;
471 }
472
473 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
474                                         struct inode *dir,
475                                         umode_t mode, dev_t dev)
476 {
477         struct inode *inode;
478
479         inode = new_inode(sb);
480         if (inode) {
481                 struct hugetlbfs_inode_info *info;
482                 inode->i_ino = get_next_ino();
483                 inode_init_owner(inode, dir, mode);
484                 inode->i_mapping->a_ops = &hugetlbfs_aops;
485                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
486                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
487                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
488                 info = HUGETLBFS_I(inode);
489                 /*
490                  * The policy is initialized here even if we are creating a
491                  * private inode because initialization simply creates an
492                  * an empty rb tree and calls spin_lock_init(), later when we
493                  * call mpol_free_shared_policy() it will just return because
494                  * the rb tree will still be empty.
495                  */
496                 mpol_shared_policy_init(&info->policy, NULL);
497                 switch (mode & S_IFMT) {
498                 default:
499                         init_special_inode(inode, mode, dev);
500                         break;
501                 case S_IFREG:
502                         inode->i_op = &hugetlbfs_inode_operations;
503                         inode->i_fop = &hugetlbfs_file_operations;
504                         break;
505                 case S_IFDIR:
506                         inode->i_op = &hugetlbfs_dir_inode_operations;
507                         inode->i_fop = &simple_dir_operations;
508
509                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
510                         inc_nlink(inode);
511                         break;
512                 case S_IFLNK:
513                         inode->i_op = &page_symlink_inode_operations;
514                         break;
515                 }
516                 lockdep_annotate_inode_mutex_key(inode);
517         }
518         return inode;
519 }
520
521 /*
522  * File creation. Allocate an inode, and we're done..
523  */
524 static int hugetlbfs_mknod(struct inode *dir,
525                         struct dentry *dentry, umode_t mode, dev_t dev)
526 {
527         struct inode *inode;
528         int error = -ENOSPC;
529
530         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
531         if (inode) {
532                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
533                 d_instantiate(dentry, inode);
534                 dget(dentry);   /* Extra count - pin the dentry in core */
535                 error = 0;
536         }
537         return error;
538 }
539
540 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
541 {
542         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
543         if (!retval)
544                 inc_nlink(dir);
545         return retval;
546 }
547
548 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, struct nameidata *nd)
549 {
550         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
551 }
552
553 static int hugetlbfs_symlink(struct inode *dir,
554                         struct dentry *dentry, const char *symname)
555 {
556         struct inode *inode;
557         int error = -ENOSPC;
558
559         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
560         if (inode) {
561                 int l = strlen(symname)+1;
562                 error = page_symlink(inode, symname, l);
563                 if (!error) {
564                         d_instantiate(dentry, inode);
565                         dget(dentry);
566                 } else
567                         iput(inode);
568         }
569         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
570
571         return error;
572 }
573
574 /*
575  * mark the head page dirty
576  */
577 static int hugetlbfs_set_page_dirty(struct page *page)
578 {
579         struct page *head = compound_head(page);
580
581         SetPageDirty(head);
582         return 0;
583 }
584
585 static int hugetlbfs_migrate_page(struct address_space *mapping,
586                                 struct page *newpage, struct page *page,
587                                 enum migrate_mode mode)
588 {
589         int rc;
590
591         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
592         if (rc)
593                 return rc;
594         migrate_page_copy(newpage, page);
595
596         return 0;
597 }
598
599 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
600 {
601         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
602         struct hstate *h = hstate_inode(dentry->d_inode);
603
604         buf->f_type = HUGETLBFS_MAGIC;
605         buf->f_bsize = huge_page_size(h);
606         if (sbinfo) {
607                 spin_lock(&sbinfo->stat_lock);
608                 /* If no limits set, just report 0 for max/free/used
609                  * blocks, like simple_statfs() */
610                 if (sbinfo->max_blocks >= 0) {
611                         buf->f_blocks = sbinfo->max_blocks;
612                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
613                         buf->f_files = sbinfo->max_inodes;
614                         buf->f_ffree = sbinfo->free_inodes;
615                 }
616                 spin_unlock(&sbinfo->stat_lock);
617         }
618         buf->f_namelen = NAME_MAX;
619         return 0;
620 }
621
622 static void hugetlbfs_put_super(struct super_block *sb)
623 {
624         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
625
626         if (sbi) {
627                 sb->s_fs_info = NULL;
628                 kfree(sbi);
629         }
630 }
631
632 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
633 {
634         if (sbinfo->free_inodes >= 0) {
635                 spin_lock(&sbinfo->stat_lock);
636                 if (unlikely(!sbinfo->free_inodes)) {
637                         spin_unlock(&sbinfo->stat_lock);
638                         return 0;
639                 }
640                 sbinfo->free_inodes--;
641                 spin_unlock(&sbinfo->stat_lock);
642         }
643
644         return 1;
645 }
646
647 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
648 {
649         if (sbinfo->free_inodes >= 0) {
650                 spin_lock(&sbinfo->stat_lock);
651                 sbinfo->free_inodes++;
652                 spin_unlock(&sbinfo->stat_lock);
653         }
654 }
655
656
657 static struct kmem_cache *hugetlbfs_inode_cachep;
658
659 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
660 {
661         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
662         struct hugetlbfs_inode_info *p;
663
664         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
665                 return NULL;
666         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
667         if (unlikely(!p)) {
668                 hugetlbfs_inc_free_inodes(sbinfo);
669                 return NULL;
670         }
671         return &p->vfs_inode;
672 }
673
674 static void hugetlbfs_i_callback(struct rcu_head *head)
675 {
676         struct inode *inode = container_of(head, struct inode, i_rcu);
677         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
678 }
679
680 static void hugetlbfs_destroy_inode(struct inode *inode)
681 {
682         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
683         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
684         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
685 }
686
687 static const struct address_space_operations hugetlbfs_aops = {
688         .write_begin    = hugetlbfs_write_begin,
689         .write_end      = hugetlbfs_write_end,
690         .set_page_dirty = hugetlbfs_set_page_dirty,
691         .migratepage    = hugetlbfs_migrate_page,
692 };
693
694
695 static void init_once(void *foo)
696 {
697         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
698
699         inode_init_once(&ei->vfs_inode);
700 }
701
702 const struct file_operations hugetlbfs_file_operations = {
703         .read                   = hugetlbfs_read,
704         .mmap                   = hugetlbfs_file_mmap,
705         .fsync                  = noop_fsync,
706         .get_unmapped_area      = hugetlb_get_unmapped_area,
707         .llseek         = default_llseek,
708 };
709
710 static const struct inode_operations hugetlbfs_dir_inode_operations = {
711         .create         = hugetlbfs_create,
712         .lookup         = simple_lookup,
713         .link           = simple_link,
714         .unlink         = simple_unlink,
715         .symlink        = hugetlbfs_symlink,
716         .mkdir          = hugetlbfs_mkdir,
717         .rmdir          = simple_rmdir,
718         .mknod          = hugetlbfs_mknod,
719         .rename         = simple_rename,
720         .setattr        = hugetlbfs_setattr,
721 };
722
723 static const struct inode_operations hugetlbfs_inode_operations = {
724         .setattr        = hugetlbfs_setattr,
725 };
726
727 static const struct super_operations hugetlbfs_ops = {
728         .alloc_inode    = hugetlbfs_alloc_inode,
729         .destroy_inode  = hugetlbfs_destroy_inode,
730         .evict_inode    = hugetlbfs_evict_inode,
731         .statfs         = hugetlbfs_statfs,
732         .put_super      = hugetlbfs_put_super,
733         .show_options   = generic_show_options,
734 };
735
736 static int
737 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
738 {
739         char *p, *rest;
740         substring_t args[MAX_OPT_ARGS];
741         int option;
742         unsigned long long size = 0;
743         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
744
745         if (!options)
746                 return 0;
747
748         while ((p = strsep(&options, ",")) != NULL) {
749                 int token;
750                 if (!*p)
751                         continue;
752
753                 token = match_token(p, tokens, args);
754                 switch (token) {
755                 case Opt_uid:
756                         if (match_int(&args[0], &option))
757                                 goto bad_val;
758                         pconfig->uid = option;
759                         break;
760
761                 case Opt_gid:
762                         if (match_int(&args[0], &option))
763                                 goto bad_val;
764                         pconfig->gid = option;
765                         break;
766
767                 case Opt_mode:
768                         if (match_octal(&args[0], &option))
769                                 goto bad_val;
770                         pconfig->mode = option & 01777U;
771                         break;
772
773                 case Opt_size: {
774                         /* memparse() will accept a K/M/G without a digit */
775                         if (!isdigit(*args[0].from))
776                                 goto bad_val;
777                         size = memparse(args[0].from, &rest);
778                         setsize = SIZE_STD;
779                         if (*rest == '%')
780                                 setsize = SIZE_PERCENT;
781                         break;
782                 }
783
784                 case Opt_nr_inodes:
785                         /* memparse() will accept a K/M/G without a digit */
786                         if (!isdigit(*args[0].from))
787                                 goto bad_val;
788                         pconfig->nr_inodes = memparse(args[0].from, &rest);
789                         break;
790
791                 case Opt_pagesize: {
792                         unsigned long ps;
793                         ps = memparse(args[0].from, &rest);
794                         pconfig->hstate = size_to_hstate(ps);
795                         if (!pconfig->hstate) {
796                                 printk(KERN_ERR
797                                 "hugetlbfs: Unsupported page size %lu MB\n",
798                                         ps >> 20);
799                                 return -EINVAL;
800                         }
801                         break;
802                 }
803
804                 default:
805                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
806                                  p);
807                         return -EINVAL;
808                         break;
809                 }
810         }
811
812         /* Do size after hstate is set up */
813         if (setsize > NO_SIZE) {
814                 struct hstate *h = pconfig->hstate;
815                 if (setsize == SIZE_PERCENT) {
816                         size <<= huge_page_shift(h);
817                         size *= h->max_huge_pages;
818                         do_div(size, 100);
819                 }
820                 pconfig->nr_blocks = (size >> huge_page_shift(h));
821         }
822
823         return 0;
824
825 bad_val:
826         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
827                args[0].from, p);
828         return -EINVAL;
829 }
830
831 static int
832 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
833 {
834         struct inode * inode;
835         struct dentry * root;
836         int ret;
837         struct hugetlbfs_config config;
838         struct hugetlbfs_sb_info *sbinfo;
839
840         save_mount_options(sb, data);
841
842         config.nr_blocks = -1; /* No limit on size by default */
843         config.nr_inodes = -1; /* No limit on number of inodes by default */
844         config.uid = current_fsuid();
845         config.gid = current_fsgid();
846         config.mode = 0755;
847         config.hstate = &default_hstate;
848         ret = hugetlbfs_parse_options(data, &config);
849         if (ret)
850                 return ret;
851
852         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
853         if (!sbinfo)
854                 return -ENOMEM;
855         sb->s_fs_info = sbinfo;
856         sbinfo->hstate = config.hstate;
857         spin_lock_init(&sbinfo->stat_lock);
858         sbinfo->max_blocks = config.nr_blocks;
859         sbinfo->free_blocks = config.nr_blocks;
860         sbinfo->max_inodes = config.nr_inodes;
861         sbinfo->free_inodes = config.nr_inodes;
862         sb->s_maxbytes = MAX_LFS_FILESIZE;
863         sb->s_blocksize = huge_page_size(config.hstate);
864         sb->s_blocksize_bits = huge_page_shift(config.hstate);
865         sb->s_magic = HUGETLBFS_MAGIC;
866         sb->s_op = &hugetlbfs_ops;
867         sb->s_time_gran = 1;
868         inode = hugetlbfs_get_root(sb, &config);
869         if (!inode)
870                 goto out_free;
871
872         root = d_alloc_root(inode);
873         if (!root) {
874                 iput(inode);
875                 goto out_free;
876         }
877         sb->s_root = root;
878         return 0;
879 out_free:
880         kfree(sbinfo);
881         return -ENOMEM;
882 }
883
884 int hugetlb_get_quota(struct address_space *mapping, long delta)
885 {
886         int ret = 0;
887         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
888
889         if (sbinfo->free_blocks > -1) {
890                 spin_lock(&sbinfo->stat_lock);
891                 if (sbinfo->free_blocks - delta >= 0)
892                         sbinfo->free_blocks -= delta;
893                 else
894                         ret = -ENOMEM;
895                 spin_unlock(&sbinfo->stat_lock);
896         }
897
898         return ret;
899 }
900
901 void hugetlb_put_quota(struct address_space *mapping, long delta)
902 {
903         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
904
905         if (sbinfo->free_blocks > -1) {
906                 spin_lock(&sbinfo->stat_lock);
907                 sbinfo->free_blocks += delta;
908                 spin_unlock(&sbinfo->stat_lock);
909         }
910 }
911
912 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
913         int flags, const char *dev_name, void *data)
914 {
915         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
916 }
917
918 static struct file_system_type hugetlbfs_fs_type = {
919         .name           = "hugetlbfs",
920         .mount          = hugetlbfs_mount,
921         .kill_sb        = kill_litter_super,
922 };
923
924 static struct vfsmount *hugetlbfs_vfsmount;
925
926 static int can_do_hugetlb_shm(void)
927 {
928         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
929 }
930
931 struct file *hugetlb_file_setup(const char *name, size_t size,
932                                 vm_flags_t acctflag,
933                                 struct user_struct **user, int creat_flags)
934 {
935         int error = -ENOMEM;
936         struct file *file;
937         struct inode *inode;
938         struct path path;
939         struct dentry *root;
940         struct qstr quick_string;
941
942         *user = NULL;
943         if (!hugetlbfs_vfsmount)
944                 return ERR_PTR(-ENOENT);
945
946         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
947                 *user = current_user();
948                 if (user_shm_lock(size, *user)) {
949                         printk_once(KERN_WARNING "Using mlock ulimits for SHM_HUGETLB is deprecated\n");
950                 } else {
951                         *user = NULL;
952                         return ERR_PTR(-EPERM);
953                 }
954         }
955
956         root = hugetlbfs_vfsmount->mnt_root;
957         quick_string.name = name;
958         quick_string.len = strlen(quick_string.name);
959         quick_string.hash = 0;
960         path.dentry = d_alloc(root, &quick_string);
961         if (!path.dentry)
962                 goto out_shm_unlock;
963
964         path.mnt = mntget(hugetlbfs_vfsmount);
965         error = -ENOSPC;
966         inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0);
967         if (!inode)
968                 goto out_dentry;
969
970         error = -ENOMEM;
971         if (hugetlb_reserve_pages(inode, 0,
972                         size >> huge_page_shift(hstate_inode(inode)), NULL,
973                         acctflag))
974                 goto out_inode;
975
976         d_instantiate(path.dentry, inode);
977         inode->i_size = size;
978         clear_nlink(inode);
979
980         error = -ENFILE;
981         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
982                         &hugetlbfs_file_operations);
983         if (!file)
984                 goto out_dentry; /* inode is already attached */
985
986         return file;
987
988 out_inode:
989         iput(inode);
990 out_dentry:
991         path_put(&path);
992 out_shm_unlock:
993         if (*user) {
994                 user_shm_unlock(size, *user);
995                 *user = NULL;
996         }
997         return ERR_PTR(error);
998 }
999
1000 static int __init init_hugetlbfs_fs(void)
1001 {
1002         int error;
1003         struct vfsmount *vfsmount;
1004
1005         error = bdi_init(&hugetlbfs_backing_dev_info);
1006         if (error)
1007                 return error;
1008
1009         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1010                                         sizeof(struct hugetlbfs_inode_info),
1011                                         0, 0, init_once);
1012         if (hugetlbfs_inode_cachep == NULL)
1013                 goto out2;
1014
1015         error = register_filesystem(&hugetlbfs_fs_type);
1016         if (error)
1017                 goto out;
1018
1019         vfsmount = kern_mount(&hugetlbfs_fs_type);
1020
1021         if (!IS_ERR(vfsmount)) {
1022                 hugetlbfs_vfsmount = vfsmount;
1023                 return 0;
1024         }
1025
1026         error = PTR_ERR(vfsmount);
1027
1028  out:
1029         if (error)
1030                 kmem_cache_destroy(hugetlbfs_inode_cachep);
1031  out2:
1032         bdi_destroy(&hugetlbfs_backing_dev_info);
1033         return error;
1034 }
1035
1036 static void __exit exit_hugetlbfs_fs(void)
1037 {
1038         kmem_cache_destroy(hugetlbfs_inode_cachep);
1039         kern_unmount(hugetlbfs_vfsmount);
1040         unregister_filesystem(&hugetlbfs_fs_type);
1041         bdi_destroy(&hugetlbfs_backing_dev_info);
1042 }
1043
1044 module_init(init_hugetlbfs_fs)
1045 module_exit(exit_hugetlbfs_fs)
1046
1047 MODULE_LICENSE("GPL");