941c8425c10b34493e9ad6fefef7fe54f451c84a
[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/ima.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_AND_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_pagesize,
57         Opt_err,
58 };
59
60 static const match_table_t tokens = {
61         {Opt_size,      "size=%s"},
62         {Opt_nr_inodes, "nr_inodes=%s"},
63         {Opt_mode,      "mode=%o"},
64         {Opt_uid,       "uid=%u"},
65         {Opt_gid,       "gid=%u"},
66         {Opt_pagesize,  "pagesize=%s"},
67         {Opt_err,       NULL},
68 };
69
70 static void huge_pagevec_release(struct pagevec *pvec)
71 {
72         int i;
73
74         for (i = 0; i < pagevec_count(pvec); ++i)
75                 put_page(pvec->pages[i]);
76
77         pagevec_reinit(pvec);
78 }
79
80 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
81 {
82         struct inode *inode = file->f_path.dentry->d_inode;
83         loff_t len, vma_len;
84         int ret;
85         struct hstate *h = hstate_file(file);
86
87         /*
88          * vma address alignment (but not the pgoff alignment) has
89          * already been checked by prepare_hugepage_range.  If you add
90          * any error returns here, do so after setting VM_HUGETLB, so
91          * is_vm_hugetlb_page tests below unmap_region go the right
92          * way when do_mmap_pgoff unwinds (may be important on powerpc
93          * and ia64).
94          */
95         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
96         vma->vm_ops = &hugetlb_vm_ops;
97
98         if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
99                 return -EINVAL;
100
101         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
102
103         mutex_lock(&inode->i_mutex);
104         file_accessed(file);
105
106         ret = -ENOMEM;
107         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
108
109         if (hugetlb_reserve_pages(inode,
110                                 vma->vm_pgoff >> huge_page_order(h),
111                                 len >> huge_page_shift(h), vma,
112                                 vma->vm_flags))
113                 goto out;
114
115         ret = 0;
116         hugetlb_prefault_arch_hook(vma->vm_mm);
117         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
118                 inode->i_size = len;
119 out:
120         mutex_unlock(&inode->i_mutex);
121
122         return ret;
123 }
124
125 /*
126  * Called under down_write(mmap_sem).
127  */
128
129 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
130 static unsigned long
131 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
132                 unsigned long len, unsigned long pgoff, unsigned long flags)
133 {
134         struct mm_struct *mm = current->mm;
135         struct vm_area_struct *vma;
136         unsigned long start_addr;
137         struct hstate *h = hstate_file(file);
138
139         if (len & ~huge_page_mask(h))
140                 return -EINVAL;
141         if (len > TASK_SIZE)
142                 return -ENOMEM;
143
144         if (flags & MAP_FIXED) {
145                 if (prepare_hugepage_range(file, addr, len))
146                         return -EINVAL;
147                 return addr;
148         }
149
150         if (addr) {
151                 addr = ALIGN(addr, huge_page_size(h));
152                 vma = find_vma(mm, addr);
153                 if (TASK_SIZE - len >= addr &&
154                     (!vma || addr + len <= vma->vm_start))
155                         return addr;
156         }
157
158         start_addr = mm->free_area_cache;
159
160         if (len <= mm->cached_hole_size)
161                 start_addr = TASK_UNMAPPED_BASE;
162
163 full_search:
164         addr = ALIGN(start_addr, huge_page_size(h));
165
166         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
167                 /* At this point:  (!vma || addr < vma->vm_end). */
168                 if (TASK_SIZE - len < addr) {
169                         /*
170                          * Start a new search - just in case we missed
171                          * some holes.
172                          */
173                         if (start_addr != TASK_UNMAPPED_BASE) {
174                                 start_addr = TASK_UNMAPPED_BASE;
175                                 goto full_search;
176                         }
177                         return -ENOMEM;
178                 }
179
180                 if (!vma || addr + len <= vma->vm_start)
181                         return addr;
182                 addr = ALIGN(vma->vm_end, huge_page_size(h));
183         }
184 }
185 #endif
186
187 static int
188 hugetlbfs_read_actor(struct page *page, unsigned long offset,
189                         char __user *buf, unsigned long count,
190                         unsigned long size)
191 {
192         char *kaddr;
193         unsigned long left, copied = 0;
194         int i, chunksize;
195
196         if (size > count)
197                 size = count;
198
199         /* Find which 4k chunk and offset with in that chunk */
200         i = offset >> PAGE_CACHE_SHIFT;
201         offset = offset & ~PAGE_CACHE_MASK;
202
203         while (size) {
204                 chunksize = PAGE_CACHE_SIZE;
205                 if (offset)
206                         chunksize -= offset;
207                 if (chunksize > size)
208                         chunksize = size;
209                 kaddr = kmap(&page[i]);
210                 left = __copy_to_user(buf, kaddr + offset, chunksize);
211                 kunmap(&page[i]);
212                 if (left) {
213                         copied += (chunksize - left);
214                         break;
215                 }
216                 offset = 0;
217                 size -= chunksize;
218                 buf += chunksize;
219                 copied += chunksize;
220                 i++;
221         }
222         return copied ? copied : -EFAULT;
223 }
224
225 /*
226  * Support for read() - Find the page attached to f_mapping and copy out the
227  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
228  * since it has PAGE_CACHE_SIZE assumptions.
229  */
230 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
231                               size_t len, loff_t *ppos)
232 {
233         struct hstate *h = hstate_file(filp);
234         struct address_space *mapping = filp->f_mapping;
235         struct inode *inode = mapping->host;
236         unsigned long index = *ppos >> huge_page_shift(h);
237         unsigned long offset = *ppos & ~huge_page_mask(h);
238         unsigned long end_index;
239         loff_t isize;
240         ssize_t retval = 0;
241
242         mutex_lock(&inode->i_mutex);
243
244         /* validate length */
245         if (len == 0)
246                 goto out;
247
248         isize = i_size_read(inode);
249         if (!isize)
250                 goto out;
251
252         end_index = (isize - 1) >> huge_page_shift(h);
253         for (;;) {
254                 struct page *page;
255                 unsigned long nr, ret;
256                 int ra;
257
258                 /* nr is the maximum number of bytes to copy from this page */
259                 nr = huge_page_size(h);
260                 if (index >= end_index) {
261                         if (index > end_index)
262                                 goto out;
263                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
264                         if (nr <= offset) {
265                                 goto out;
266                         }
267                 }
268                 nr = nr - offset;
269
270                 /* Find the page */
271                 page = find_get_page(mapping, index);
272                 if (unlikely(page == NULL)) {
273                         /*
274                          * We have a HOLE, zero out the user-buffer for the
275                          * length of the hole or request.
276                          */
277                         ret = len < nr ? len : nr;
278                         if (clear_user(buf, ret))
279                                 ra = -EFAULT;
280                         else
281                                 ra = 0;
282                 } else {
283                         /*
284                          * We have the page, copy it to user space buffer.
285                          */
286                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
287                         ret = ra;
288                 }
289                 if (ra < 0) {
290                         if (retval == 0)
291                                 retval = ra;
292                         if (page)
293                                 page_cache_release(page);
294                         goto out;
295                 }
296
297                 offset += ret;
298                 retval += ret;
299                 len -= ret;
300                 index += offset >> huge_page_shift(h);
301                 offset &= ~huge_page_mask(h);
302
303                 if (page)
304                         page_cache_release(page);
305
306                 /* short read or no more work */
307                 if ((ret != nr) || (len == 0))
308                         break;
309         }
310 out:
311         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
312         mutex_unlock(&inode->i_mutex);
313         return retval;
314 }
315
316 static int hugetlbfs_write_begin(struct file *file,
317                         struct address_space *mapping,
318                         loff_t pos, unsigned len, unsigned flags,
319                         struct page **pagep, void **fsdata)
320 {
321         return -EINVAL;
322 }
323
324 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
325                         loff_t pos, unsigned len, unsigned copied,
326                         struct page *page, void *fsdata)
327 {
328         BUG();
329         return -EINVAL;
330 }
331
332 static void truncate_huge_page(struct page *page)
333 {
334         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
335         ClearPageUptodate(page);
336         remove_from_page_cache(page);
337         put_page(page);
338 }
339
340 static void truncate_hugepages(struct inode *inode, loff_t lstart)
341 {
342         struct hstate *h = hstate_inode(inode);
343         struct address_space *mapping = &inode->i_data;
344         const pgoff_t start = lstart >> huge_page_shift(h);
345         struct pagevec pvec;
346         pgoff_t next;
347         int i, freed = 0;
348
349         pagevec_init(&pvec, 0);
350         next = start;
351         while (1) {
352                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
353                         if (next == start)
354                                 break;
355                         next = start;
356                         continue;
357                 }
358
359                 for (i = 0; i < pagevec_count(&pvec); ++i) {
360                         struct page *page = pvec.pages[i];
361
362                         lock_page(page);
363                         if (page->index > next)
364                                 next = page->index;
365                         ++next;
366                         truncate_huge_page(page);
367                         unlock_page(page);
368                         freed++;
369                 }
370                 huge_pagevec_release(&pvec);
371         }
372         BUG_ON(!lstart && mapping->nrpages);
373         hugetlb_unreserve_pages(inode, start, freed);
374 }
375
376 static void hugetlbfs_delete_inode(struct inode *inode)
377 {
378         truncate_hugepages(inode, 0);
379         clear_inode(inode);
380 }
381
382 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
383 {
384         struct super_block *sb = inode->i_sb;
385
386         if (!hlist_unhashed(&inode->i_hash)) {
387                 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
388                         list_move(&inode->i_list, &inode_unused);
389                 inodes_stat.nr_unused++;
390                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
391                         spin_unlock(&inode_lock);
392                         return;
393                 }
394                 inode->i_state |= I_WILL_FREE;
395                 spin_unlock(&inode_lock);
396                 /*
397                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
398                  * in our backing_dev_info.
399                  */
400                 write_inode_now(inode, 1);
401                 spin_lock(&inode_lock);
402                 inode->i_state &= ~I_WILL_FREE;
403                 inodes_stat.nr_unused--;
404                 hlist_del_init(&inode->i_hash);
405         }
406         list_del_init(&inode->i_list);
407         list_del_init(&inode->i_sb_list);
408         inode->i_state |= I_FREEING;
409         inodes_stat.nr_inodes--;
410         spin_unlock(&inode_lock);
411         truncate_hugepages(inode, 0);
412         clear_inode(inode);
413         destroy_inode(inode);
414 }
415
416 static void hugetlbfs_drop_inode(struct inode *inode)
417 {
418         if (!inode->i_nlink)
419                 generic_delete_inode(inode);
420         else
421                 hugetlbfs_forget_inode(inode);
422 }
423
424 static inline void
425 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
426 {
427         struct vm_area_struct *vma;
428         struct prio_tree_iter iter;
429
430         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
431                 unsigned long v_offset;
432
433                 /*
434                  * Can the expression below overflow on 32-bit arches?
435                  * No, because the prio_tree returns us only those vmas
436                  * which overlap the truncated area starting at pgoff,
437                  * and no vma on a 32-bit arch can span beyond the 4GB.
438                  */
439                 if (vma->vm_pgoff < pgoff)
440                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
441                 else
442                         v_offset = 0;
443
444                 __unmap_hugepage_range(vma,
445                                 vma->vm_start + v_offset, vma->vm_end, NULL);
446         }
447 }
448
449 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
450 {
451         pgoff_t pgoff;
452         struct address_space *mapping = inode->i_mapping;
453         struct hstate *h = hstate_inode(inode);
454
455         BUG_ON(offset & ~huge_page_mask(h));
456         pgoff = offset >> PAGE_SHIFT;
457
458         i_size_write(inode, offset);
459         spin_lock(&mapping->i_mmap_lock);
460         if (!prio_tree_empty(&mapping->i_mmap))
461                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
462         spin_unlock(&mapping->i_mmap_lock);
463         truncate_hugepages(inode, offset);
464         return 0;
465 }
466
467 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
468 {
469         struct inode *inode = dentry->d_inode;
470         struct hstate *h = hstate_inode(inode);
471         int error;
472         unsigned int ia_valid = attr->ia_valid;
473
474         BUG_ON(!inode);
475
476         error = inode_change_ok(inode, attr);
477         if (error)
478                 goto out;
479
480         if (ia_valid & ATTR_SIZE) {
481                 error = -EINVAL;
482                 if (!(attr->ia_size & ~huge_page_mask(h)))
483                         error = hugetlb_vmtruncate(inode, attr->ia_size);
484                 if (error)
485                         goto out;
486                 attr->ia_valid &= ~ATTR_SIZE;
487         }
488         error = inode_setattr(inode, attr);
489 out:
490         return error;
491 }
492
493 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
494                                         gid_t gid, int mode, dev_t dev)
495 {
496         struct inode *inode;
497
498         inode = new_inode(sb);
499         if (inode) {
500                 struct hugetlbfs_inode_info *info;
501                 inode->i_mode = mode;
502                 inode->i_uid = uid;
503                 inode->i_gid = gid;
504                 inode->i_mapping->a_ops = &hugetlbfs_aops;
505                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
506                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
507                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
508                 info = HUGETLBFS_I(inode);
509                 mpol_shared_policy_init(&info->policy, NULL);
510                 switch (mode & S_IFMT) {
511                 default:
512                         init_special_inode(inode, mode, dev);
513                         break;
514                 case S_IFREG:
515                         inode->i_op = &hugetlbfs_inode_operations;
516                         inode->i_fop = &hugetlbfs_file_operations;
517                         break;
518                 case S_IFDIR:
519                         inode->i_op = &hugetlbfs_dir_inode_operations;
520                         inode->i_fop = &simple_dir_operations;
521
522                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
523                         inc_nlink(inode);
524                         break;
525                 case S_IFLNK:
526                         inode->i_op = &page_symlink_inode_operations;
527                         break;
528                 }
529         }
530         return inode;
531 }
532
533 /*
534  * File creation. Allocate an inode, and we're done..
535  */
536 static int hugetlbfs_mknod(struct inode *dir,
537                         struct dentry *dentry, int mode, dev_t dev)
538 {
539         struct inode *inode;
540         int error = -ENOSPC;
541         gid_t gid;
542
543         if (dir->i_mode & S_ISGID) {
544                 gid = dir->i_gid;
545                 if (S_ISDIR(mode))
546                         mode |= S_ISGID;
547         } else {
548                 gid = current_fsgid();
549         }
550         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
551         if (inode) {
552                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
553                 d_instantiate(dentry, inode);
554                 dget(dentry);   /* Extra count - pin the dentry in core */
555                 error = 0;
556         }
557         return error;
558 }
559
560 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
561 {
562         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
563         if (!retval)
564                 inc_nlink(dir);
565         return retval;
566 }
567
568 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
569 {
570         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
571 }
572
573 static int hugetlbfs_symlink(struct inode *dir,
574                         struct dentry *dentry, const char *symname)
575 {
576         struct inode *inode;
577         int error = -ENOSPC;
578         gid_t gid;
579
580         if (dir->i_mode & S_ISGID)
581                 gid = dir->i_gid;
582         else
583                 gid = current_fsgid();
584
585         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
586                                         gid, S_IFLNK|S_IRWXUGO, 0);
587         if (inode) {
588                 int l = strlen(symname)+1;
589                 error = page_symlink(inode, symname, l);
590                 if (!error) {
591                         d_instantiate(dentry, inode);
592                         dget(dentry);
593                 } else
594                         iput(inode);
595         }
596         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
597
598         return error;
599 }
600
601 /*
602  * mark the head page dirty
603  */
604 static int hugetlbfs_set_page_dirty(struct page *page)
605 {
606         struct page *head = compound_head(page);
607
608         SetPageDirty(head);
609         return 0;
610 }
611
612 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
613 {
614         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
615         struct hstate *h = hstate_inode(dentry->d_inode);
616
617         buf->f_type = HUGETLBFS_MAGIC;
618         buf->f_bsize = huge_page_size(h);
619         if (sbinfo) {
620                 spin_lock(&sbinfo->stat_lock);
621                 /* If no limits set, just report 0 for max/free/used
622                  * blocks, like simple_statfs() */
623                 if (sbinfo->max_blocks >= 0) {
624                         buf->f_blocks = sbinfo->max_blocks;
625                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
626                         buf->f_files = sbinfo->max_inodes;
627                         buf->f_ffree = sbinfo->free_inodes;
628                 }
629                 spin_unlock(&sbinfo->stat_lock);
630         }
631         buf->f_namelen = NAME_MAX;
632         return 0;
633 }
634
635 static void hugetlbfs_put_super(struct super_block *sb)
636 {
637         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
638
639         if (sbi) {
640                 sb->s_fs_info = NULL;
641                 kfree(sbi);
642         }
643 }
644
645 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
646 {
647         if (sbinfo->free_inodes >= 0) {
648                 spin_lock(&sbinfo->stat_lock);
649                 if (unlikely(!sbinfo->free_inodes)) {
650                         spin_unlock(&sbinfo->stat_lock);
651                         return 0;
652                 }
653                 sbinfo->free_inodes--;
654                 spin_unlock(&sbinfo->stat_lock);
655         }
656
657         return 1;
658 }
659
660 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
661 {
662         if (sbinfo->free_inodes >= 0) {
663                 spin_lock(&sbinfo->stat_lock);
664                 sbinfo->free_inodes++;
665                 spin_unlock(&sbinfo->stat_lock);
666         }
667 }
668
669
670 static struct kmem_cache *hugetlbfs_inode_cachep;
671
672 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
673 {
674         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
675         struct hugetlbfs_inode_info *p;
676
677         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
678                 return NULL;
679         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
680         if (unlikely(!p)) {
681                 hugetlbfs_inc_free_inodes(sbinfo);
682                 return NULL;
683         }
684         return &p->vfs_inode;
685 }
686
687 static void hugetlbfs_destroy_inode(struct inode *inode)
688 {
689         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
690         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
691         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
692 }
693
694 static const struct address_space_operations hugetlbfs_aops = {
695         .write_begin    = hugetlbfs_write_begin,
696         .write_end      = hugetlbfs_write_end,
697         .set_page_dirty = hugetlbfs_set_page_dirty,
698 };
699
700
701 static void init_once(void *foo)
702 {
703         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
704
705         inode_init_once(&ei->vfs_inode);
706 }
707
708 const struct file_operations hugetlbfs_file_operations = {
709         .read                   = hugetlbfs_read,
710         .mmap                   = hugetlbfs_file_mmap,
711         .fsync                  = simple_sync_file,
712         .get_unmapped_area      = hugetlb_get_unmapped_area,
713 };
714
715 static const struct inode_operations hugetlbfs_dir_inode_operations = {
716         .create         = hugetlbfs_create,
717         .lookup         = simple_lookup,
718         .link           = simple_link,
719         .unlink         = simple_unlink,
720         .symlink        = hugetlbfs_symlink,
721         .mkdir          = hugetlbfs_mkdir,
722         .rmdir          = simple_rmdir,
723         .mknod          = hugetlbfs_mknod,
724         .rename         = simple_rename,
725         .setattr        = hugetlbfs_setattr,
726 };
727
728 static const struct inode_operations hugetlbfs_inode_operations = {
729         .setattr        = hugetlbfs_setattr,
730 };
731
732 static const struct super_operations hugetlbfs_ops = {
733         .alloc_inode    = hugetlbfs_alloc_inode,
734         .destroy_inode  = hugetlbfs_destroy_inode,
735         .statfs         = hugetlbfs_statfs,
736         .delete_inode   = hugetlbfs_delete_inode,
737         .drop_inode     = hugetlbfs_drop_inode,
738         .put_super      = hugetlbfs_put_super,
739         .show_options   = generic_show_options,
740 };
741
742 static int
743 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
744 {
745         char *p, *rest;
746         substring_t args[MAX_OPT_ARGS];
747         int option;
748         unsigned long long size = 0;
749         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
750
751         if (!options)
752                 return 0;
753
754         while ((p = strsep(&options, ",")) != NULL) {
755                 int token;
756                 if (!*p)
757                         continue;
758
759                 token = match_token(p, tokens, args);
760                 switch (token) {
761                 case Opt_uid:
762                         if (match_int(&args[0], &option))
763                                 goto bad_val;
764                         pconfig->uid = option;
765                         break;
766
767                 case Opt_gid:
768                         if (match_int(&args[0], &option))
769                                 goto bad_val;
770                         pconfig->gid = option;
771                         break;
772
773                 case Opt_mode:
774                         if (match_octal(&args[0], &option))
775                                 goto bad_val;
776                         pconfig->mode = option & 01777U;
777                         break;
778
779                 case Opt_size: {
780                         /* memparse() will accept a K/M/G without a digit */
781                         if (!isdigit(*args[0].from))
782                                 goto bad_val;
783                         size = memparse(args[0].from, &rest);
784                         setsize = SIZE_STD;
785                         if (*rest == '%')
786                                 setsize = SIZE_PERCENT;
787                         break;
788                 }
789
790                 case Opt_nr_inodes:
791                         /* memparse() will accept a K/M/G without a digit */
792                         if (!isdigit(*args[0].from))
793                                 goto bad_val;
794                         pconfig->nr_inodes = memparse(args[0].from, &rest);
795                         break;
796
797                 case Opt_pagesize: {
798                         unsigned long ps;
799                         ps = memparse(args[0].from, &rest);
800                         pconfig->hstate = size_to_hstate(ps);
801                         if (!pconfig->hstate) {
802                                 printk(KERN_ERR
803                                 "hugetlbfs: Unsupported page size %lu MB\n",
804                                         ps >> 20);
805                                 return -EINVAL;
806                         }
807                         break;
808                 }
809
810                 default:
811                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
812                                  p);
813                         return -EINVAL;
814                         break;
815                 }
816         }
817
818         /* Do size after hstate is set up */
819         if (setsize > NO_SIZE) {
820                 struct hstate *h = pconfig->hstate;
821                 if (setsize == SIZE_PERCENT) {
822                         size <<= huge_page_shift(h);
823                         size *= h->max_huge_pages;
824                         do_div(size, 100);
825                 }
826                 pconfig->nr_blocks = (size >> huge_page_shift(h));
827         }
828
829         return 0;
830
831 bad_val:
832         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
833                args[0].from, p);
834         return -EINVAL;
835 }
836
837 static int
838 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
839 {
840         struct inode * inode;
841         struct dentry * root;
842         int ret;
843         struct hugetlbfs_config config;
844         struct hugetlbfs_sb_info *sbinfo;
845
846         save_mount_options(sb, data);
847
848         config.nr_blocks = -1; /* No limit on size by default */
849         config.nr_inodes = -1; /* No limit on number of inodes by default */
850         config.uid = current_fsuid();
851         config.gid = current_fsgid();
852         config.mode = 0755;
853         config.hstate = &default_hstate;
854         ret = hugetlbfs_parse_options(data, &config);
855         if (ret)
856                 return ret;
857
858         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
859         if (!sbinfo)
860                 return -ENOMEM;
861         sb->s_fs_info = sbinfo;
862         sbinfo->hstate = config.hstate;
863         spin_lock_init(&sbinfo->stat_lock);
864         sbinfo->max_blocks = config.nr_blocks;
865         sbinfo->free_blocks = config.nr_blocks;
866         sbinfo->max_inodes = config.nr_inodes;
867         sbinfo->free_inodes = config.nr_inodes;
868         sb->s_maxbytes = MAX_LFS_FILESIZE;
869         sb->s_blocksize = huge_page_size(config.hstate);
870         sb->s_blocksize_bits = huge_page_shift(config.hstate);
871         sb->s_magic = HUGETLBFS_MAGIC;
872         sb->s_op = &hugetlbfs_ops;
873         sb->s_time_gran = 1;
874         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
875                                         S_IFDIR | config.mode, 0);
876         if (!inode)
877                 goto out_free;
878
879         root = d_alloc_root(inode);
880         if (!root) {
881                 iput(inode);
882                 goto out_free;
883         }
884         sb->s_root = root;
885         return 0;
886 out_free:
887         kfree(sbinfo);
888         return -ENOMEM;
889 }
890
891 int hugetlb_get_quota(struct address_space *mapping, long delta)
892 {
893         int ret = 0;
894         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
895
896         if (sbinfo->free_blocks > -1) {
897                 spin_lock(&sbinfo->stat_lock);
898                 if (sbinfo->free_blocks - delta >= 0)
899                         sbinfo->free_blocks -= delta;
900                 else
901                         ret = -ENOMEM;
902                 spin_unlock(&sbinfo->stat_lock);
903         }
904
905         return ret;
906 }
907
908 void hugetlb_put_quota(struct address_space *mapping, long delta)
909 {
910         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
911
912         if (sbinfo->free_blocks > -1) {
913                 spin_lock(&sbinfo->stat_lock);
914                 sbinfo->free_blocks += delta;
915                 spin_unlock(&sbinfo->stat_lock);
916         }
917 }
918
919 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
920         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
921 {
922         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
923 }
924
925 static struct file_system_type hugetlbfs_fs_type = {
926         .name           = "hugetlbfs",
927         .get_sb         = hugetlbfs_get_sb,
928         .kill_sb        = kill_litter_super,
929 };
930
931 static struct vfsmount *hugetlbfs_vfsmount;
932
933 static int can_do_hugetlb_shm(void)
934 {
935         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
936 }
937
938 struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag)
939 {
940         int error = -ENOMEM;
941         int unlock_shm = 0;
942         struct file *file;
943         struct inode *inode;
944         struct dentry *dentry, *root;
945         struct qstr quick_string;
946         struct user_struct *user = current_user();
947
948         if (!hugetlbfs_vfsmount)
949                 return ERR_PTR(-ENOENT);
950
951         if (!can_do_hugetlb_shm()) {
952                 if (user_shm_lock(size, user)) {
953                         unlock_shm = 1;
954                         WARN_ONCE(1,
955                           "Using mlock ulimits for SHM_HUGETLB deprecated\n");
956                 } else
957                         return ERR_PTR(-EPERM);
958         }
959
960         root = hugetlbfs_vfsmount->mnt_root;
961         quick_string.name = name;
962         quick_string.len = strlen(quick_string.name);
963         quick_string.hash = 0;
964         dentry = d_alloc(root, &quick_string);
965         if (!dentry)
966                 goto out_shm_unlock;
967
968         error = -ENOSPC;
969         inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
970                                 current_fsgid(), S_IFREG | S_IRWXUGO, 0);
971         if (!inode)
972                 goto out_dentry;
973
974         error = -ENOMEM;
975         if (hugetlb_reserve_pages(inode, 0,
976                         size >> huge_page_shift(hstate_inode(inode)), NULL,
977                         acctflag))
978                 goto out_inode;
979
980         d_instantiate(dentry, inode);
981         inode->i_size = size;
982         inode->i_nlink = 0;
983
984         error = -ENFILE;
985         file = alloc_file(hugetlbfs_vfsmount, dentry,
986                         FMODE_WRITE | FMODE_READ,
987                         &hugetlbfs_file_operations);
988         if (!file)
989                 goto out_dentry; /* inode is already attached */
990         ima_counts_get(file);
991
992         return file;
993
994 out_inode:
995         iput(inode);
996 out_dentry:
997         dput(dentry);
998 out_shm_unlock:
999         if (unlock_shm)
1000                 user_shm_unlock(size, user);
1001         return ERR_PTR(error);
1002 }
1003
1004 static int __init init_hugetlbfs_fs(void)
1005 {
1006         int error;
1007         struct vfsmount *vfsmount;
1008
1009         error = bdi_init(&hugetlbfs_backing_dev_info);
1010         if (error)
1011                 return error;
1012
1013         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1014                                         sizeof(struct hugetlbfs_inode_info),
1015                                         0, 0, init_once);
1016         if (hugetlbfs_inode_cachep == NULL)
1017                 goto out2;
1018
1019         error = register_filesystem(&hugetlbfs_fs_type);
1020         if (error)
1021                 goto out;
1022
1023         vfsmount = kern_mount(&hugetlbfs_fs_type);
1024
1025         if (!IS_ERR(vfsmount)) {
1026                 hugetlbfs_vfsmount = vfsmount;
1027                 return 0;
1028         }
1029
1030         error = PTR_ERR(vfsmount);
1031
1032  out:
1033         if (error)
1034                 kmem_cache_destroy(hugetlbfs_inode_cachep);
1035  out2:
1036         bdi_destroy(&hugetlbfs_backing_dev_info);
1037         return error;
1038 }
1039
1040 static void __exit exit_hugetlbfs_fs(void)
1041 {
1042         kmem_cache_destroy(hugetlbfs_inode_cachep);
1043         unregister_filesystem(&hugetlbfs_fs_type);
1044         bdi_destroy(&hugetlbfs_backing_dev_info);
1045 }
1046
1047 module_init(init_hugetlbfs_fs)
1048 module_exit(exit_hugetlbfs_fs)
1049
1050 MODULE_LICENSE("GPL");