[PATCH] slab: remove kmem_cache_t
[linux-3.10.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/writeback.h>
17 #include <linux/pagemap.h>
18 #include <linux/highmem.h>
19 #include <linux/init.h>
20 #include <linux/string.h>
21 #include <linux/capability.h>
22 #include <linux/backing-dev.h>
23 #include <linux/hugetlb.h>
24 #include <linux/pagevec.h>
25 #include <linux/quotaops.h>
26 #include <linux/slab.h>
27 #include <linux/dnotify.h>
28 #include <linux/statfs.h>
29 #include <linux/security.h>
30
31 #include <asm/uaccess.h>
32
33 /* some random number */
34 #define HUGETLBFS_MAGIC 0x958458f6
35
36 static struct super_operations hugetlbfs_ops;
37 static const struct address_space_operations hugetlbfs_aops;
38 const struct file_operations hugetlbfs_file_operations;
39 static struct inode_operations hugetlbfs_dir_inode_operations;
40 static struct inode_operations hugetlbfs_inode_operations;
41
42 static struct backing_dev_info hugetlbfs_backing_dev_info = {
43         .ra_pages       = 0,    /* No readahead */
44         .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
45 };
46
47 int sysctl_hugetlb_shm_group;
48
49 static void huge_pagevec_release(struct pagevec *pvec)
50 {
51         int i;
52
53         for (i = 0; i < pagevec_count(pvec); ++i)
54                 put_page(pvec->pages[i]);
55
56         pagevec_reinit(pvec);
57 }
58
59 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
60 {
61         struct inode *inode = file->f_dentry->d_inode;
62         loff_t len, vma_len;
63         int ret;
64
65         /*
66          * vma alignment has already been checked by prepare_hugepage_range.
67          * If you add any error returns here, do so after setting VM_HUGETLB,
68          * so is_vm_hugetlb_page tests below unmap_region go the right way
69          * when do_mmap_pgoff unwinds (may be important on powerpc and ia64).
70          */
71         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
72         vma->vm_ops = &hugetlb_vm_ops;
73
74         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
75
76         mutex_lock(&inode->i_mutex);
77         file_accessed(file);
78
79         ret = -ENOMEM;
80         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
81
82         if (vma->vm_flags & VM_MAYSHARE &&
83             hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
84                                   len >> HPAGE_SHIFT))
85                 goto out;
86
87         ret = 0;
88         hugetlb_prefault_arch_hook(vma->vm_mm);
89         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
90                 inode->i_size = len;
91 out:
92         mutex_unlock(&inode->i_mutex);
93
94         return ret;
95 }
96
97 /*
98  * Called under down_write(mmap_sem).
99  */
100
101 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
102 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
103                 unsigned long len, unsigned long pgoff, unsigned long flags);
104 #else
105 static unsigned long
106 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
107                 unsigned long len, unsigned long pgoff, unsigned long flags)
108 {
109         struct mm_struct *mm = current->mm;
110         struct vm_area_struct *vma;
111         unsigned long start_addr;
112
113         if (len & ~HPAGE_MASK)
114                 return -EINVAL;
115         if (len > TASK_SIZE)
116                 return -ENOMEM;
117
118         if (addr) {
119                 addr = ALIGN(addr, HPAGE_SIZE);
120                 vma = find_vma(mm, addr);
121                 if (TASK_SIZE - len >= addr &&
122                     (!vma || addr + len <= vma->vm_start))
123                         return addr;
124         }
125
126         start_addr = mm->free_area_cache;
127
128         if (len <= mm->cached_hole_size)
129                 start_addr = TASK_UNMAPPED_BASE;
130
131 full_search:
132         addr = ALIGN(start_addr, HPAGE_SIZE);
133
134         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
135                 /* At this point:  (!vma || addr < vma->vm_end). */
136                 if (TASK_SIZE - len < addr) {
137                         /*
138                          * Start a new search - just in case we missed
139                          * some holes.
140                          */
141                         if (start_addr != TASK_UNMAPPED_BASE) {
142                                 start_addr = TASK_UNMAPPED_BASE;
143                                 goto full_search;
144                         }
145                         return -ENOMEM;
146                 }
147
148                 if (!vma || addr + len <= vma->vm_start)
149                         return addr;
150                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
151         }
152 }
153 #endif
154
155 /*
156  * Read a page. Again trivial. If it didn't already exist
157  * in the page cache, it is zero-filled.
158  */
159 static int hugetlbfs_readpage(struct file *file, struct page * page)
160 {
161         unlock_page(page);
162         return -EINVAL;
163 }
164
165 static int hugetlbfs_prepare_write(struct file *file,
166                         struct page *page, unsigned offset, unsigned to)
167 {
168         return -EINVAL;
169 }
170
171 static int hugetlbfs_commit_write(struct file *file,
172                         struct page *page, unsigned offset, unsigned to)
173 {
174         return -EINVAL;
175 }
176
177 static void truncate_huge_page(struct page *page)
178 {
179         clear_page_dirty(page);
180         ClearPageUptodate(page);
181         remove_from_page_cache(page);
182         put_page(page);
183 }
184
185 static void truncate_hugepages(struct inode *inode, loff_t lstart)
186 {
187         struct address_space *mapping = &inode->i_data;
188         const pgoff_t start = lstart >> HPAGE_SHIFT;
189         struct pagevec pvec;
190         pgoff_t next;
191         int i, freed = 0;
192
193         pagevec_init(&pvec, 0);
194         next = start;
195         while (1) {
196                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
197                         if (next == start)
198                                 break;
199                         next = start;
200                         continue;
201                 }
202
203                 for (i = 0; i < pagevec_count(&pvec); ++i) {
204                         struct page *page = pvec.pages[i];
205
206                         lock_page(page);
207                         if (page->index > next)
208                                 next = page->index;
209                         ++next;
210                         truncate_huge_page(page);
211                         unlock_page(page);
212                         hugetlb_put_quota(mapping);
213                         freed++;
214                 }
215                 huge_pagevec_release(&pvec);
216         }
217         BUG_ON(!lstart && mapping->nrpages);
218         hugetlb_unreserve_pages(inode, start, freed);
219 }
220
221 static void hugetlbfs_delete_inode(struct inode *inode)
222 {
223         truncate_hugepages(inode, 0);
224         clear_inode(inode);
225 }
226
227 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
228 {
229         struct super_block *sb = inode->i_sb;
230
231         if (!hlist_unhashed(&inode->i_hash)) {
232                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
233                         list_move(&inode->i_list, &inode_unused);
234                 inodes_stat.nr_unused++;
235                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
236                         spin_unlock(&inode_lock);
237                         return;
238                 }
239                 inode->i_state |= I_WILL_FREE;
240                 spin_unlock(&inode_lock);
241                 /*
242                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
243                  * in our backing_dev_info.
244                  */
245                 write_inode_now(inode, 1);
246                 spin_lock(&inode_lock);
247                 inode->i_state &= ~I_WILL_FREE;
248                 inodes_stat.nr_unused--;
249                 hlist_del_init(&inode->i_hash);
250         }
251         list_del_init(&inode->i_list);
252         list_del_init(&inode->i_sb_list);
253         inode->i_state |= I_FREEING;
254         inodes_stat.nr_inodes--;
255         spin_unlock(&inode_lock);
256         truncate_hugepages(inode, 0);
257         clear_inode(inode);
258         destroy_inode(inode);
259 }
260
261 static void hugetlbfs_drop_inode(struct inode *inode)
262 {
263         if (!inode->i_nlink)
264                 generic_delete_inode(inode);
265         else
266                 hugetlbfs_forget_inode(inode);
267 }
268
269 static inline void
270 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
271 {
272         struct vm_area_struct *vma;
273         struct prio_tree_iter iter;
274
275         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
276                 unsigned long v_offset;
277
278                 /*
279                  * Can the expression below overflow on 32-bit arches?
280                  * No, because the prio_tree returns us only those vmas
281                  * which overlap the truncated area starting at pgoff,
282                  * and no vma on a 32-bit arch can span beyond the 4GB.
283                  */
284                 if (vma->vm_pgoff < pgoff)
285                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
286                 else
287                         v_offset = 0;
288
289                 __unmap_hugepage_range(vma,
290                                 vma->vm_start + v_offset, vma->vm_end);
291         }
292 }
293
294 /*
295  * Expanding truncates are not allowed.
296  */
297 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
298 {
299         pgoff_t pgoff;
300         struct address_space *mapping = inode->i_mapping;
301
302         if (offset > inode->i_size)
303                 return -EINVAL;
304
305         BUG_ON(offset & ~HPAGE_MASK);
306         pgoff = offset >> PAGE_SHIFT;
307
308         inode->i_size = offset;
309         spin_lock(&mapping->i_mmap_lock);
310         if (!prio_tree_empty(&mapping->i_mmap))
311                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
312         spin_unlock(&mapping->i_mmap_lock);
313         truncate_hugepages(inode, offset);
314         return 0;
315 }
316
317 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
318 {
319         struct inode *inode = dentry->d_inode;
320         int error;
321         unsigned int ia_valid = attr->ia_valid;
322
323         BUG_ON(!inode);
324
325         error = inode_change_ok(inode, attr);
326         if (error)
327                 goto out;
328
329         if (ia_valid & ATTR_SIZE) {
330                 error = -EINVAL;
331                 if (!(attr->ia_size & ~HPAGE_MASK))
332                         error = hugetlb_vmtruncate(inode, attr->ia_size);
333                 if (error)
334                         goto out;
335                 attr->ia_valid &= ~ATTR_SIZE;
336         }
337         error = inode_setattr(inode, attr);
338 out:
339         return error;
340 }
341
342 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
343                                         gid_t gid, int mode, dev_t dev)
344 {
345         struct inode *inode;
346
347         inode = new_inode(sb);
348         if (inode) {
349                 struct hugetlbfs_inode_info *info;
350                 inode->i_mode = mode;
351                 inode->i_uid = uid;
352                 inode->i_gid = gid;
353                 inode->i_blocks = 0;
354                 inode->i_mapping->a_ops = &hugetlbfs_aops;
355                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
356                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
357                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
358                 info = HUGETLBFS_I(inode);
359                 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
360                 switch (mode & S_IFMT) {
361                 default:
362                         init_special_inode(inode, mode, dev);
363                         break;
364                 case S_IFREG:
365                         inode->i_op = &hugetlbfs_inode_operations;
366                         inode->i_fop = &hugetlbfs_file_operations;
367                         break;
368                 case S_IFDIR:
369                         inode->i_op = &hugetlbfs_dir_inode_operations;
370                         inode->i_fop = &simple_dir_operations;
371
372                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
373                         inc_nlink(inode);
374                         break;
375                 case S_IFLNK:
376                         inode->i_op = &page_symlink_inode_operations;
377                         break;
378                 }
379         }
380         return inode;
381 }
382
383 /*
384  * File creation. Allocate an inode, and we're done..
385  */
386 static int hugetlbfs_mknod(struct inode *dir,
387                         struct dentry *dentry, int mode, dev_t dev)
388 {
389         struct inode *inode;
390         int error = -ENOSPC;
391         gid_t gid;
392
393         if (dir->i_mode & S_ISGID) {
394                 gid = dir->i_gid;
395                 if (S_ISDIR(mode))
396                         mode |= S_ISGID;
397         } else {
398                 gid = current->fsgid;
399         }
400         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
401         if (inode) {
402                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
403                 d_instantiate(dentry, inode);
404                 dget(dentry);   /* Extra count - pin the dentry in core */
405                 error = 0;
406         }
407         return error;
408 }
409
410 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
411 {
412         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
413         if (!retval)
414                 inc_nlink(dir);
415         return retval;
416 }
417
418 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
419 {
420         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
421 }
422
423 static int hugetlbfs_symlink(struct inode *dir,
424                         struct dentry *dentry, const char *symname)
425 {
426         struct inode *inode;
427         int error = -ENOSPC;
428         gid_t gid;
429
430         if (dir->i_mode & S_ISGID)
431                 gid = dir->i_gid;
432         else
433                 gid = current->fsgid;
434
435         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
436                                         gid, S_IFLNK|S_IRWXUGO, 0);
437         if (inode) {
438                 int l = strlen(symname)+1;
439                 error = page_symlink(inode, symname, l);
440                 if (!error) {
441                         d_instantiate(dentry, inode);
442                         dget(dentry);
443                 } else
444                         iput(inode);
445         }
446         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
447
448         return error;
449 }
450
451 /*
452  * For direct-IO reads into hugetlb pages
453  */
454 static int hugetlbfs_set_page_dirty(struct page *page)
455 {
456         return 0;
457 }
458
459 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
460 {
461         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
462
463         buf->f_type = HUGETLBFS_MAGIC;
464         buf->f_bsize = HPAGE_SIZE;
465         if (sbinfo) {
466                 spin_lock(&sbinfo->stat_lock);
467                 /* If no limits set, just report 0 for max/free/used
468                  * blocks, like simple_statfs() */
469                 if (sbinfo->max_blocks >= 0) {
470                         buf->f_blocks = sbinfo->max_blocks;
471                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
472                         buf->f_files = sbinfo->max_inodes;
473                         buf->f_ffree = sbinfo->free_inodes;
474                 }
475                 spin_unlock(&sbinfo->stat_lock);
476         }
477         buf->f_namelen = NAME_MAX;
478         return 0;
479 }
480
481 static void hugetlbfs_put_super(struct super_block *sb)
482 {
483         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
484
485         if (sbi) {
486                 sb->s_fs_info = NULL;
487                 kfree(sbi);
488         }
489 }
490
491 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
492 {
493         if (sbinfo->free_inodes >= 0) {
494                 spin_lock(&sbinfo->stat_lock);
495                 if (unlikely(!sbinfo->free_inodes)) {
496                         spin_unlock(&sbinfo->stat_lock);
497                         return 0;
498                 }
499                 sbinfo->free_inodes--;
500                 spin_unlock(&sbinfo->stat_lock);
501         }
502
503         return 1;
504 }
505
506 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
507 {
508         if (sbinfo->free_inodes >= 0) {
509                 spin_lock(&sbinfo->stat_lock);
510                 sbinfo->free_inodes++;
511                 spin_unlock(&sbinfo->stat_lock);
512         }
513 }
514
515
516 static struct kmem_cache *hugetlbfs_inode_cachep;
517
518 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
519 {
520         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
521         struct hugetlbfs_inode_info *p;
522
523         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
524                 return NULL;
525         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
526         if (unlikely(!p)) {
527                 hugetlbfs_inc_free_inodes(sbinfo);
528                 return NULL;
529         }
530         return &p->vfs_inode;
531 }
532
533 static void hugetlbfs_destroy_inode(struct inode *inode)
534 {
535         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
536         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
537         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
538 }
539
540 static const struct address_space_operations hugetlbfs_aops = {
541         .readpage       = hugetlbfs_readpage,
542         .prepare_write  = hugetlbfs_prepare_write,
543         .commit_write   = hugetlbfs_commit_write,
544         .set_page_dirty = hugetlbfs_set_page_dirty,
545 };
546
547
548 static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags)
549 {
550         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
551
552         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
553             SLAB_CTOR_CONSTRUCTOR)
554                 inode_init_once(&ei->vfs_inode);
555 }
556
557 const struct file_operations hugetlbfs_file_operations = {
558         .mmap                   = hugetlbfs_file_mmap,
559         .fsync                  = simple_sync_file,
560         .get_unmapped_area      = hugetlb_get_unmapped_area,
561 };
562
563 static struct inode_operations hugetlbfs_dir_inode_operations = {
564         .create         = hugetlbfs_create,
565         .lookup         = simple_lookup,
566         .link           = simple_link,
567         .unlink         = simple_unlink,
568         .symlink        = hugetlbfs_symlink,
569         .mkdir          = hugetlbfs_mkdir,
570         .rmdir          = simple_rmdir,
571         .mknod          = hugetlbfs_mknod,
572         .rename         = simple_rename,
573         .setattr        = hugetlbfs_setattr,
574 };
575
576 static struct inode_operations hugetlbfs_inode_operations = {
577         .setattr        = hugetlbfs_setattr,
578 };
579
580 static struct super_operations hugetlbfs_ops = {
581         .alloc_inode    = hugetlbfs_alloc_inode,
582         .destroy_inode  = hugetlbfs_destroy_inode,
583         .statfs         = hugetlbfs_statfs,
584         .delete_inode   = hugetlbfs_delete_inode,
585         .drop_inode     = hugetlbfs_drop_inode,
586         .put_super      = hugetlbfs_put_super,
587 };
588
589 static int
590 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
591 {
592         char *opt, *value, *rest;
593
594         if (!options)
595                 return 0;
596         while ((opt = strsep(&options, ",")) != NULL) {
597                 if (!*opt)
598                         continue;
599
600                 value = strchr(opt, '=');
601                 if (!value || !*value)
602                         return -EINVAL;
603                 else
604                         *value++ = '\0';
605
606                 if (!strcmp(opt, "uid"))
607                         pconfig->uid = simple_strtoul(value, &value, 0);
608                 else if (!strcmp(opt, "gid"))
609                         pconfig->gid = simple_strtoul(value, &value, 0);
610                 else if (!strcmp(opt, "mode"))
611                         pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
612                 else if (!strcmp(opt, "size")) {
613                         unsigned long long size = memparse(value, &rest);
614                         if (*rest == '%') {
615                                 size <<= HPAGE_SHIFT;
616                                 size *= max_huge_pages;
617                                 do_div(size, 100);
618                                 rest++;
619                         }
620                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
621                         value = rest;
622                 } else if (!strcmp(opt,"nr_inodes")) {
623                         pconfig->nr_inodes = memparse(value, &rest);
624                         value = rest;
625                 } else
626                         return -EINVAL;
627
628                 if (*value)
629                         return -EINVAL;
630         }
631         return 0;
632 }
633
634 static int
635 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
636 {
637         struct inode * inode;
638         struct dentry * root;
639         int ret;
640         struct hugetlbfs_config config;
641         struct hugetlbfs_sb_info *sbinfo;
642
643         config.nr_blocks = -1; /* No limit on size by default */
644         config.nr_inodes = -1; /* No limit on number of inodes by default */
645         config.uid = current->fsuid;
646         config.gid = current->fsgid;
647         config.mode = 0755;
648         ret = hugetlbfs_parse_options(data, &config);
649
650         if (ret)
651                 return ret;
652
653         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
654         if (!sbinfo)
655                 return -ENOMEM;
656         sb->s_fs_info = sbinfo;
657         spin_lock_init(&sbinfo->stat_lock);
658         sbinfo->max_blocks = config.nr_blocks;
659         sbinfo->free_blocks = config.nr_blocks;
660         sbinfo->max_inodes = config.nr_inodes;
661         sbinfo->free_inodes = config.nr_inodes;
662         sb->s_maxbytes = MAX_LFS_FILESIZE;
663         sb->s_blocksize = HPAGE_SIZE;
664         sb->s_blocksize_bits = HPAGE_SHIFT;
665         sb->s_magic = HUGETLBFS_MAGIC;
666         sb->s_op = &hugetlbfs_ops;
667         sb->s_time_gran = 1;
668         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
669                                         S_IFDIR | config.mode, 0);
670         if (!inode)
671                 goto out_free;
672
673         root = d_alloc_root(inode);
674         if (!root) {
675                 iput(inode);
676                 goto out_free;
677         }
678         sb->s_root = root;
679         return 0;
680 out_free:
681         kfree(sbinfo);
682         return -ENOMEM;
683 }
684
685 int hugetlb_get_quota(struct address_space *mapping)
686 {
687         int ret = 0;
688         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
689
690         if (sbinfo->free_blocks > -1) {
691                 spin_lock(&sbinfo->stat_lock);
692                 if (sbinfo->free_blocks > 0)
693                         sbinfo->free_blocks--;
694                 else
695                         ret = -ENOMEM;
696                 spin_unlock(&sbinfo->stat_lock);
697         }
698
699         return ret;
700 }
701
702 void hugetlb_put_quota(struct address_space *mapping)
703 {
704         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
705
706         if (sbinfo->free_blocks > -1) {
707                 spin_lock(&sbinfo->stat_lock);
708                 sbinfo->free_blocks++;
709                 spin_unlock(&sbinfo->stat_lock);
710         }
711 }
712
713 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
714         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
715 {
716         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
717 }
718
719 static struct file_system_type hugetlbfs_fs_type = {
720         .name           = "hugetlbfs",
721         .get_sb         = hugetlbfs_get_sb,
722         .kill_sb        = kill_litter_super,
723 };
724
725 static struct vfsmount *hugetlbfs_vfsmount;
726
727 static int can_do_hugetlb_shm(void)
728 {
729         return likely(capable(CAP_IPC_LOCK) ||
730                         in_group_p(sysctl_hugetlb_shm_group) ||
731                         can_do_mlock());
732 }
733
734 struct file *hugetlb_zero_setup(size_t size)
735 {
736         int error = -ENOMEM;
737         struct file *file;
738         struct inode *inode;
739         struct dentry *dentry, *root;
740         struct qstr quick_string;
741         char buf[16];
742         static atomic_t counter;
743
744         if (!can_do_hugetlb_shm())
745                 return ERR_PTR(-EPERM);
746
747         if (!user_shm_lock(size, current->user))
748                 return ERR_PTR(-ENOMEM);
749
750         root = hugetlbfs_vfsmount->mnt_root;
751         snprintf(buf, 16, "%u", atomic_inc_return(&counter));
752         quick_string.name = buf;
753         quick_string.len = strlen(quick_string.name);
754         quick_string.hash = 0;
755         dentry = d_alloc(root, &quick_string);
756         if (!dentry)
757                 goto out_shm_unlock;
758
759         error = -ENFILE;
760         file = get_empty_filp();
761         if (!file)
762                 goto out_dentry;
763
764         error = -ENOSPC;
765         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
766                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
767         if (!inode)
768                 goto out_file;
769
770         error = -ENOMEM;
771         if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
772                 goto out_inode;
773
774         d_instantiate(dentry, inode);
775         inode->i_size = size;
776         inode->i_nlink = 0;
777         file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
778         file->f_dentry = dentry;
779         file->f_mapping = inode->i_mapping;
780         file->f_op = &hugetlbfs_file_operations;
781         file->f_mode = FMODE_WRITE | FMODE_READ;
782         return file;
783
784 out_inode:
785         iput(inode);
786 out_file:
787         put_filp(file);
788 out_dentry:
789         dput(dentry);
790 out_shm_unlock:
791         user_shm_unlock(size, current->user);
792         return ERR_PTR(error);
793 }
794
795 static int __init init_hugetlbfs_fs(void)
796 {
797         int error;
798         struct vfsmount *vfsmount;
799
800         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
801                                         sizeof(struct hugetlbfs_inode_info),
802                                         0, 0, init_once, NULL);
803         if (hugetlbfs_inode_cachep == NULL)
804                 return -ENOMEM;
805
806         error = register_filesystem(&hugetlbfs_fs_type);
807         if (error)
808                 goto out;
809
810         vfsmount = kern_mount(&hugetlbfs_fs_type);
811
812         if (!IS_ERR(vfsmount)) {
813                 hugetlbfs_vfsmount = vfsmount;
814                 return 0;
815         }
816
817         error = PTR_ERR(vfsmount);
818
819  out:
820         if (error)
821                 kmem_cache_destroy(hugetlbfs_inode_cachep);
822         return error;
823 }
824
825 static void __exit exit_hugetlbfs_fs(void)
826 {
827         kmem_cache_destroy(hugetlbfs_inode_cachep);
828         unregister_filesystem(&hugetlbfs_fs_type);
829 }
830
831 module_init(init_hugetlbfs_fs)
832 module_exit(exit_hugetlbfs_fs)
833
834 MODULE_LICENSE("GPL");