c848a191525db4776bec08970538449c442ffb81
[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/quotaops.h>
30 #include <linux/slab.h>
31 #include <linux/dnotify.h>
32 #include <linux/statfs.h>
33 #include <linux/security.h>
34
35 #include <asm/uaccess.h>
36
37 /* some random number */
38 #define HUGETLBFS_MAGIC 0x958458f6
39
40 static const struct super_operations hugetlbfs_ops;
41 static const struct address_space_operations hugetlbfs_aops;
42 const struct file_operations hugetlbfs_file_operations;
43 static const struct inode_operations hugetlbfs_dir_inode_operations;
44 static const struct inode_operations hugetlbfs_inode_operations;
45
46 static struct backing_dev_info hugetlbfs_backing_dev_info = {
47         .ra_pages       = 0,    /* No readahead */
48         .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
49 };
50
51 int sysctl_hugetlb_shm_group;
52
53 enum {
54         Opt_size, Opt_nr_inodes,
55         Opt_mode, Opt_uid, Opt_gid,
56         Opt_err,
57 };
58
59 static 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_err,       NULL},
66 };
67
68 static void huge_pagevec_release(struct pagevec *pvec)
69 {
70         int i;
71
72         for (i = 0; i < pagevec_count(pvec); ++i)
73                 put_page(pvec->pages[i]);
74
75         pagevec_reinit(pvec);
76 }
77
78 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
79 {
80         struct inode *inode = file->f_path.dentry->d_inode;
81         loff_t len, vma_len;
82         int ret;
83
84         /*
85          * vma alignment has already been checked by prepare_hugepage_range.
86          * If you add any error returns here, do so after setting VM_HUGETLB,
87          * so is_vm_hugetlb_page tests below unmap_region go the right way
88          * when do_mmap_pgoff unwinds (may be important on powerpc and ia64).
89          */
90         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
91         vma->vm_ops = &hugetlb_vm_ops;
92
93         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
94
95         mutex_lock(&inode->i_mutex);
96         file_accessed(file);
97
98         ret = -ENOMEM;
99         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
100
101         if (vma->vm_flags & VM_MAYSHARE &&
102             hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
103                                   len >> HPAGE_SHIFT))
104                 goto out;
105
106         ret = 0;
107         hugetlb_prefault_arch_hook(vma->vm_mm);
108         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
109                 inode->i_size = len;
110 out:
111         mutex_unlock(&inode->i_mutex);
112
113         return ret;
114 }
115
116 /*
117  * Called under down_write(mmap_sem).
118  */
119
120 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
121 static unsigned long
122 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
123                 unsigned long len, unsigned long pgoff, unsigned long flags)
124 {
125         struct mm_struct *mm = current->mm;
126         struct vm_area_struct *vma;
127         unsigned long start_addr;
128
129         if (len & ~HPAGE_MASK)
130                 return -EINVAL;
131         if (len > TASK_SIZE)
132                 return -ENOMEM;
133
134         if (flags & MAP_FIXED) {
135                 if (prepare_hugepage_range(addr, len, pgoff))
136                         return -EINVAL;
137                 return addr;
138         }
139
140         if (addr) {
141                 addr = ALIGN(addr, HPAGE_SIZE);
142                 vma = find_vma(mm, addr);
143                 if (TASK_SIZE - len >= addr &&
144                     (!vma || addr + len <= vma->vm_start))
145                         return addr;
146         }
147
148         start_addr = mm->free_area_cache;
149
150         if (len <= mm->cached_hole_size)
151                 start_addr = TASK_UNMAPPED_BASE;
152
153 full_search:
154         addr = ALIGN(start_addr, HPAGE_SIZE);
155
156         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
157                 /* At this point:  (!vma || addr < vma->vm_end). */
158                 if (TASK_SIZE - len < addr) {
159                         /*
160                          * Start a new search - just in case we missed
161                          * some holes.
162                          */
163                         if (start_addr != TASK_UNMAPPED_BASE) {
164                                 start_addr = TASK_UNMAPPED_BASE;
165                                 goto full_search;
166                         }
167                         return -ENOMEM;
168                 }
169
170                 if (!vma || addr + len <= vma->vm_start)
171                         return addr;
172                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
173         }
174 }
175 #endif
176
177 /*
178  * Read a page. Again trivial. If it didn't already exist
179  * in the page cache, it is zero-filled.
180  */
181 static int hugetlbfs_readpage(struct file *file, struct page * page)
182 {
183         unlock_page(page);
184         return -EINVAL;
185 }
186
187 static int hugetlbfs_prepare_write(struct file *file,
188                         struct page *page, unsigned offset, unsigned to)
189 {
190         return -EINVAL;
191 }
192
193 static int hugetlbfs_commit_write(struct file *file,
194                         struct page *page, unsigned offset, unsigned to)
195 {
196         return -EINVAL;
197 }
198
199 static void truncate_huge_page(struct page *page)
200 {
201         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
202         ClearPageUptodate(page);
203         remove_from_page_cache(page);
204         put_page(page);
205 }
206
207 static void truncate_hugepages(struct inode *inode, loff_t lstart)
208 {
209         struct address_space *mapping = &inode->i_data;
210         const pgoff_t start = lstart >> HPAGE_SHIFT;
211         struct pagevec pvec;
212         pgoff_t next;
213         int i, freed = 0;
214
215         pagevec_init(&pvec, 0);
216         next = start;
217         while (1) {
218                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
219                         if (next == start)
220                                 break;
221                         next = start;
222                         continue;
223                 }
224
225                 for (i = 0; i < pagevec_count(&pvec); ++i) {
226                         struct page *page = pvec.pages[i];
227
228                         lock_page(page);
229                         if (page->index > next)
230                                 next = page->index;
231                         ++next;
232                         truncate_huge_page(page);
233                         unlock_page(page);
234                         hugetlb_put_quota(mapping);
235                         freed++;
236                 }
237                 huge_pagevec_release(&pvec);
238         }
239         BUG_ON(!lstart && mapping->nrpages);
240         hugetlb_unreserve_pages(inode, start, freed);
241 }
242
243 static void hugetlbfs_delete_inode(struct inode *inode)
244 {
245         truncate_hugepages(inode, 0);
246         clear_inode(inode);
247 }
248
249 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
250 {
251         struct super_block *sb = inode->i_sb;
252
253         if (!hlist_unhashed(&inode->i_hash)) {
254                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
255                         list_move(&inode->i_list, &inode_unused);
256                 inodes_stat.nr_unused++;
257                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
258                         spin_unlock(&inode_lock);
259                         return;
260                 }
261                 inode->i_state |= I_WILL_FREE;
262                 spin_unlock(&inode_lock);
263                 /*
264                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
265                  * in our backing_dev_info.
266                  */
267                 write_inode_now(inode, 1);
268                 spin_lock(&inode_lock);
269                 inode->i_state &= ~I_WILL_FREE;
270                 inodes_stat.nr_unused--;
271                 hlist_del_init(&inode->i_hash);
272         }
273         list_del_init(&inode->i_list);
274         list_del_init(&inode->i_sb_list);
275         inode->i_state |= I_FREEING;
276         inodes_stat.nr_inodes--;
277         spin_unlock(&inode_lock);
278         truncate_hugepages(inode, 0);
279         clear_inode(inode);
280         destroy_inode(inode);
281 }
282
283 static void hugetlbfs_drop_inode(struct inode *inode)
284 {
285         if (!inode->i_nlink)
286                 generic_delete_inode(inode);
287         else
288                 hugetlbfs_forget_inode(inode);
289 }
290
291 static inline void
292 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
293 {
294         struct vm_area_struct *vma;
295         struct prio_tree_iter iter;
296
297         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
298                 unsigned long v_offset;
299
300                 /*
301                  * Can the expression below overflow on 32-bit arches?
302                  * No, because the prio_tree returns us only those vmas
303                  * which overlap the truncated area starting at pgoff,
304                  * and no vma on a 32-bit arch can span beyond the 4GB.
305                  */
306                 if (vma->vm_pgoff < pgoff)
307                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
308                 else
309                         v_offset = 0;
310
311                 __unmap_hugepage_range(vma,
312                                 vma->vm_start + v_offset, vma->vm_end);
313         }
314 }
315
316 /*
317  * Expanding truncates are not allowed.
318  */
319 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
320 {
321         pgoff_t pgoff;
322         struct address_space *mapping = inode->i_mapping;
323
324         if (offset > inode->i_size)
325                 return -EINVAL;
326
327         BUG_ON(offset & ~HPAGE_MASK);
328         pgoff = offset >> PAGE_SHIFT;
329
330         inode->i_size = offset;
331         spin_lock(&mapping->i_mmap_lock);
332         if (!prio_tree_empty(&mapping->i_mmap))
333                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
334         spin_unlock(&mapping->i_mmap_lock);
335         truncate_hugepages(inode, offset);
336         return 0;
337 }
338
339 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
340 {
341         struct inode *inode = dentry->d_inode;
342         int error;
343         unsigned int ia_valid = attr->ia_valid;
344
345         BUG_ON(!inode);
346
347         error = inode_change_ok(inode, attr);
348         if (error)
349                 goto out;
350
351         if (ia_valid & ATTR_SIZE) {
352                 error = -EINVAL;
353                 if (!(attr->ia_size & ~HPAGE_MASK))
354                         error = hugetlb_vmtruncate(inode, attr->ia_size);
355                 if (error)
356                         goto out;
357                 attr->ia_valid &= ~ATTR_SIZE;
358         }
359         error = inode_setattr(inode, attr);
360 out:
361         return error;
362 }
363
364 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
365                                         gid_t gid, int mode, dev_t dev)
366 {
367         struct inode *inode;
368
369         inode = new_inode(sb);
370         if (inode) {
371                 struct hugetlbfs_inode_info *info;
372                 inode->i_mode = mode;
373                 inode->i_uid = uid;
374                 inode->i_gid = gid;
375                 inode->i_blocks = 0;
376                 inode->i_mapping->a_ops = &hugetlbfs_aops;
377                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
378                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
379                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
380                 info = HUGETLBFS_I(inode);
381                 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
382                 switch (mode & S_IFMT) {
383                 default:
384                         init_special_inode(inode, mode, dev);
385                         break;
386                 case S_IFREG:
387                         inode->i_op = &hugetlbfs_inode_operations;
388                         inode->i_fop = &hugetlbfs_file_operations;
389                         break;
390                 case S_IFDIR:
391                         inode->i_op = &hugetlbfs_dir_inode_operations;
392                         inode->i_fop = &simple_dir_operations;
393
394                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
395                         inc_nlink(inode);
396                         break;
397                 case S_IFLNK:
398                         inode->i_op = &page_symlink_inode_operations;
399                         break;
400                 }
401         }
402         return inode;
403 }
404
405 /*
406  * File creation. Allocate an inode, and we're done..
407  */
408 static int hugetlbfs_mknod(struct inode *dir,
409                         struct dentry *dentry, int mode, dev_t dev)
410 {
411         struct inode *inode;
412         int error = -ENOSPC;
413         gid_t gid;
414
415         if (dir->i_mode & S_ISGID) {
416                 gid = dir->i_gid;
417                 if (S_ISDIR(mode))
418                         mode |= S_ISGID;
419         } else {
420                 gid = current->fsgid;
421         }
422         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
423         if (inode) {
424                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
425                 d_instantiate(dentry, inode);
426                 dget(dentry);   /* Extra count - pin the dentry in core */
427                 error = 0;
428         }
429         return error;
430 }
431
432 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
433 {
434         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
435         if (!retval)
436                 inc_nlink(dir);
437         return retval;
438 }
439
440 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
441 {
442         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
443 }
444
445 static int hugetlbfs_symlink(struct inode *dir,
446                         struct dentry *dentry, const char *symname)
447 {
448         struct inode *inode;
449         int error = -ENOSPC;
450         gid_t gid;
451
452         if (dir->i_mode & S_ISGID)
453                 gid = dir->i_gid;
454         else
455                 gid = current->fsgid;
456
457         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
458                                         gid, S_IFLNK|S_IRWXUGO, 0);
459         if (inode) {
460                 int l = strlen(symname)+1;
461                 error = page_symlink(inode, symname, l);
462                 if (!error) {
463                         d_instantiate(dentry, inode);
464                         dget(dentry);
465                 } else
466                         iput(inode);
467         }
468         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
469
470         return error;
471 }
472
473 /*
474  * mark the head page dirty
475  */
476 static int hugetlbfs_set_page_dirty(struct page *page)
477 {
478         struct page *head = compound_head(page);
479
480         SetPageDirty(head);
481         return 0;
482 }
483
484 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
485 {
486         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
487
488         buf->f_type = HUGETLBFS_MAGIC;
489         buf->f_bsize = HPAGE_SIZE;
490         if (sbinfo) {
491                 spin_lock(&sbinfo->stat_lock);
492                 /* If no limits set, just report 0 for max/free/used
493                  * blocks, like simple_statfs() */
494                 if (sbinfo->max_blocks >= 0) {
495                         buf->f_blocks = sbinfo->max_blocks;
496                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
497                         buf->f_files = sbinfo->max_inodes;
498                         buf->f_ffree = sbinfo->free_inodes;
499                 }
500                 spin_unlock(&sbinfo->stat_lock);
501         }
502         buf->f_namelen = NAME_MAX;
503         return 0;
504 }
505
506 static void hugetlbfs_put_super(struct super_block *sb)
507 {
508         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
509
510         if (sbi) {
511                 sb->s_fs_info = NULL;
512                 kfree(sbi);
513         }
514 }
515
516 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
517 {
518         if (sbinfo->free_inodes >= 0) {
519                 spin_lock(&sbinfo->stat_lock);
520                 if (unlikely(!sbinfo->free_inodes)) {
521                         spin_unlock(&sbinfo->stat_lock);
522                         return 0;
523                 }
524                 sbinfo->free_inodes--;
525                 spin_unlock(&sbinfo->stat_lock);
526         }
527
528         return 1;
529 }
530
531 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
532 {
533         if (sbinfo->free_inodes >= 0) {
534                 spin_lock(&sbinfo->stat_lock);
535                 sbinfo->free_inodes++;
536                 spin_unlock(&sbinfo->stat_lock);
537         }
538 }
539
540
541 static struct kmem_cache *hugetlbfs_inode_cachep;
542
543 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
544 {
545         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
546         struct hugetlbfs_inode_info *p;
547
548         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
549                 return NULL;
550         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
551         if (unlikely(!p)) {
552                 hugetlbfs_inc_free_inodes(sbinfo);
553                 return NULL;
554         }
555         return &p->vfs_inode;
556 }
557
558 static void hugetlbfs_destroy_inode(struct inode *inode)
559 {
560         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
561         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
562         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
563 }
564
565 static const struct address_space_operations hugetlbfs_aops = {
566         .readpage       = hugetlbfs_readpage,
567         .prepare_write  = hugetlbfs_prepare_write,
568         .commit_write   = hugetlbfs_commit_write,
569         .set_page_dirty = hugetlbfs_set_page_dirty,
570 };
571
572
573 static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags)
574 {
575         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
576
577         inode_init_once(&ei->vfs_inode);
578 }
579
580 const struct file_operations hugetlbfs_file_operations = {
581         .mmap                   = hugetlbfs_file_mmap,
582         .fsync                  = simple_sync_file,
583         .get_unmapped_area      = hugetlb_get_unmapped_area,
584 };
585
586 static const struct inode_operations hugetlbfs_dir_inode_operations = {
587         .create         = hugetlbfs_create,
588         .lookup         = simple_lookup,
589         .link           = simple_link,
590         .unlink         = simple_unlink,
591         .symlink        = hugetlbfs_symlink,
592         .mkdir          = hugetlbfs_mkdir,
593         .rmdir          = simple_rmdir,
594         .mknod          = hugetlbfs_mknod,
595         .rename         = simple_rename,
596         .setattr        = hugetlbfs_setattr,
597 };
598
599 static const struct inode_operations hugetlbfs_inode_operations = {
600         .setattr        = hugetlbfs_setattr,
601 };
602
603 static const struct super_operations hugetlbfs_ops = {
604         .alloc_inode    = hugetlbfs_alloc_inode,
605         .destroy_inode  = hugetlbfs_destroy_inode,
606         .statfs         = hugetlbfs_statfs,
607         .delete_inode   = hugetlbfs_delete_inode,
608         .drop_inode     = hugetlbfs_drop_inode,
609         .put_super      = hugetlbfs_put_super,
610 };
611
612 static int
613 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
614 {
615         char *p, *rest;
616         substring_t args[MAX_OPT_ARGS];
617         int option;
618
619         if (!options)
620                 return 0;
621
622         while ((p = strsep(&options, ",")) != NULL) {
623                 int token;
624                 if (!*p)
625                         continue;
626
627                 token = match_token(p, tokens, args);
628                 switch (token) {
629                 case Opt_uid:
630                         if (match_int(&args[0], &option))
631                                 goto bad_val;
632                         pconfig->uid = option;
633                         break;
634
635                 case Opt_gid:
636                         if (match_int(&args[0], &option))
637                                 goto bad_val;
638                         pconfig->gid = option;
639                         break;
640
641                 case Opt_mode:
642                         if (match_octal(&args[0], &option))
643                                 goto bad_val;
644                         pconfig->mode = option & 0777U;
645                         break;
646
647                 case Opt_size: {
648                         unsigned long long size;
649                         /* memparse() will accept a K/M/G without a digit */
650                         if (!isdigit(*args[0].from))
651                                 goto bad_val;
652                         size = memparse(args[0].from, &rest);
653                         if (*rest == '%') {
654                                 size <<= HPAGE_SHIFT;
655                                 size *= max_huge_pages;
656                                 do_div(size, 100);
657                         }
658                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
659                         break;
660                 }
661
662                 case Opt_nr_inodes:
663                         /* memparse() will accept a K/M/G without a digit */
664                         if (!isdigit(*args[0].from))
665                                 goto bad_val;
666                         pconfig->nr_inodes = memparse(args[0].from, &rest);
667                         break;
668
669                 default:
670                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
671                                  p);
672                         return -EINVAL;
673                         break;
674                 }
675         }
676         return 0;
677
678 bad_val:
679         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
680                args[0].from, p);
681         return 1;
682 }
683
684 static int
685 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
686 {
687         struct inode * inode;
688         struct dentry * root;
689         int ret;
690         struct hugetlbfs_config config;
691         struct hugetlbfs_sb_info *sbinfo;
692
693         config.nr_blocks = -1; /* No limit on size by default */
694         config.nr_inodes = -1; /* No limit on number of inodes by default */
695         config.uid = current->fsuid;
696         config.gid = current->fsgid;
697         config.mode = 0755;
698         ret = hugetlbfs_parse_options(data, &config);
699         if (ret)
700                 return ret;
701
702         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
703         if (!sbinfo)
704                 return -ENOMEM;
705         sb->s_fs_info = sbinfo;
706         spin_lock_init(&sbinfo->stat_lock);
707         sbinfo->max_blocks = config.nr_blocks;
708         sbinfo->free_blocks = config.nr_blocks;
709         sbinfo->max_inodes = config.nr_inodes;
710         sbinfo->free_inodes = config.nr_inodes;
711         sb->s_maxbytes = MAX_LFS_FILESIZE;
712         sb->s_blocksize = HPAGE_SIZE;
713         sb->s_blocksize_bits = HPAGE_SHIFT;
714         sb->s_magic = HUGETLBFS_MAGIC;
715         sb->s_op = &hugetlbfs_ops;
716         sb->s_time_gran = 1;
717         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
718                                         S_IFDIR | config.mode, 0);
719         if (!inode)
720                 goto out_free;
721
722         root = d_alloc_root(inode);
723         if (!root) {
724                 iput(inode);
725                 goto out_free;
726         }
727         sb->s_root = root;
728         return 0;
729 out_free:
730         kfree(sbinfo);
731         return -ENOMEM;
732 }
733
734 int hugetlb_get_quota(struct address_space *mapping)
735 {
736         int ret = 0;
737         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
738
739         if (sbinfo->free_blocks > -1) {
740                 spin_lock(&sbinfo->stat_lock);
741                 if (sbinfo->free_blocks > 0)
742                         sbinfo->free_blocks--;
743                 else
744                         ret = -ENOMEM;
745                 spin_unlock(&sbinfo->stat_lock);
746         }
747
748         return ret;
749 }
750
751 void hugetlb_put_quota(struct address_space *mapping)
752 {
753         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
754
755         if (sbinfo->free_blocks > -1) {
756                 spin_lock(&sbinfo->stat_lock);
757                 sbinfo->free_blocks++;
758                 spin_unlock(&sbinfo->stat_lock);
759         }
760 }
761
762 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
763         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
764 {
765         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
766 }
767
768 static struct file_system_type hugetlbfs_fs_type = {
769         .name           = "hugetlbfs",
770         .get_sb         = hugetlbfs_get_sb,
771         .kill_sb        = kill_litter_super,
772 };
773
774 static struct vfsmount *hugetlbfs_vfsmount;
775
776 static int can_do_hugetlb_shm(void)
777 {
778         return likely(capable(CAP_IPC_LOCK) ||
779                         in_group_p(sysctl_hugetlb_shm_group) ||
780                         can_do_mlock());
781 }
782
783 struct file *hugetlb_file_setup(const char *name, size_t size)
784 {
785         int error = -ENOMEM;
786         struct file *file;
787         struct inode *inode;
788         struct dentry *dentry, *root;
789         struct qstr quick_string;
790
791         if (!hugetlbfs_vfsmount)
792                 return ERR_PTR(-ENOENT);
793
794         if (!can_do_hugetlb_shm())
795                 return ERR_PTR(-EPERM);
796
797         if (!user_shm_lock(size, current->user))
798                 return ERR_PTR(-ENOMEM);
799
800         root = hugetlbfs_vfsmount->mnt_root;
801         quick_string.name = name;
802         quick_string.len = strlen(quick_string.name);
803         quick_string.hash = 0;
804         dentry = d_alloc(root, &quick_string);
805         if (!dentry)
806                 goto out_shm_unlock;
807
808         error = -ENFILE;
809         file = get_empty_filp();
810         if (!file)
811                 goto out_dentry;
812
813         error = -ENOSPC;
814         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
815                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
816         if (!inode)
817                 goto out_file;
818
819         error = -ENOMEM;
820         if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
821                 goto out_inode;
822
823         d_instantiate(dentry, inode);
824         inode->i_size = size;
825         inode->i_nlink = 0;
826         file->f_path.mnt = mntget(hugetlbfs_vfsmount);
827         file->f_path.dentry = dentry;
828         file->f_mapping = inode->i_mapping;
829         file->f_op = &hugetlbfs_file_operations;
830         file->f_mode = FMODE_WRITE | FMODE_READ;
831         return file;
832
833 out_inode:
834         iput(inode);
835 out_file:
836         put_filp(file);
837 out_dentry:
838         dput(dentry);
839 out_shm_unlock:
840         user_shm_unlock(size, current->user);
841         return ERR_PTR(error);
842 }
843
844 static int __init init_hugetlbfs_fs(void)
845 {
846         int error;
847         struct vfsmount *vfsmount;
848
849         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
850                                         sizeof(struct hugetlbfs_inode_info),
851                                         0, 0, init_once);
852         if (hugetlbfs_inode_cachep == NULL)
853                 return -ENOMEM;
854
855         error = register_filesystem(&hugetlbfs_fs_type);
856         if (error)
857                 goto out;
858
859         vfsmount = kern_mount(&hugetlbfs_fs_type);
860
861         if (!IS_ERR(vfsmount)) {
862                 hugetlbfs_vfsmount = vfsmount;
863                 return 0;
864         }
865
866         error = PTR_ERR(vfsmount);
867
868  out:
869         if (error)
870                 kmem_cache_destroy(hugetlbfs_inode_cachep);
871         return error;
872 }
873
874 static void __exit exit_hugetlbfs_fs(void)
875 {
876         kmem_cache_destroy(hugetlbfs_inode_cachep);
877         unregister_filesystem(&hugetlbfs_fs_type);
878 }
879
880 module_init(init_hugetlbfs_fs)
881 module_exit(exit_hugetlbfs_fs)
882
883 MODULE_LICENSE("GPL");