blob: e026c807e6b376fe57deb2dc2050d1d58d7c917a [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/backing-dev.h>
22#include <linux/hugetlb.h>
23#include <linux/pagevec.h>
24#include <linux/quotaops.h>
25#include <linux/slab.h>
26#include <linux/dnotify.h>
27#include <linux/statfs.h>
28#include <linux/security.h>
29
30#include <asm/uaccess.h>
31
32/* some random number */
33#define HUGETLBFS_MAGIC 0x958458f6
34
35static struct super_operations hugetlbfs_ops;
36static struct address_space_operations hugetlbfs_aops;
37struct file_operations hugetlbfs_file_operations;
38static struct inode_operations hugetlbfs_dir_inode_operations;
39static struct inode_operations hugetlbfs_inode_operations;
40
41static struct backing_dev_info hugetlbfs_backing_dev_info = {
42 .ra_pages = 0, /* No readahead */
43 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
44};
45
46int sysctl_hugetlb_shm_group;
47
Adam Litke2e9b3672005-10-29 18:16:47 -070048static void huge_pagevec_release(struct pagevec *pvec)
49{
50 int i;
51
52 for (i = 0; i < pagevec_count(pvec); ++i)
53 put_page(pvec->pages[i]);
54
55 pagevec_reinit(pvec);
56}
57
58/*
59 * huge_pages_needed tries to determine the number of new huge pages that
60 * will be required to fully populate this VMA. This will be equal to
61 * the size of the VMA in huge pages minus the number of huge pages
62 * (covered by this VMA) that are found in the page cache.
63 *
64 * Result is in bytes to be compatible with is_hugepage_mem_enough()
65 */
66unsigned long
67huge_pages_needed(struct address_space *mapping, struct vm_area_struct *vma)
68{
69 int i;
70 struct pagevec pvec;
71 unsigned long start = vma->vm_start;
72 unsigned long end = vma->vm_end;
73 unsigned long hugepages = (end - start) >> HPAGE_SHIFT;
74 pgoff_t next = vma->vm_pgoff;
75 pgoff_t endpg = next + ((end - start) >> PAGE_SHIFT);
76
77 pagevec_init(&pvec, 0);
78 while (next < endpg) {
79 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
80 break;
81 for (i = 0; i < pagevec_count(&pvec); i++) {
82 struct page *page = pvec.pages[i];
83 if (page->index > next)
84 next = page->index;
85 if (page->index >= endpg)
86 break;
87 next++;
88 hugepages--;
89 }
90 huge_pagevec_release(&pvec);
91 }
92 return hugepages << HPAGE_SHIFT;
93}
94
Linus Torvalds1da177e2005-04-16 15:20:36 -070095static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
96{
97 struct inode *inode = file->f_dentry->d_inode;
Adam Litke2e9b3672005-10-29 18:16:47 -070098 struct address_space *mapping = inode->i_mapping;
99 unsigned long bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 loff_t len, vma_len;
101 int ret;
102
103 if ((vma->vm_flags & (VM_MAYSHARE | VM_WRITE)) == VM_WRITE)
104 return -EINVAL;
105
106 if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
107 return -EINVAL;
108
109 if (vma->vm_start & ~HPAGE_MASK)
110 return -EINVAL;
111
112 if (vma->vm_end & ~HPAGE_MASK)
113 return -EINVAL;
114
115 if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
116 return -EINVAL;
117
Adam Litke2e9b3672005-10-29 18:16:47 -0700118 bytes = huge_pages_needed(mapping, vma);
119 if (!is_hugepage_mem_enough(bytes))
120 return -ENOMEM;
121
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
123
124 down(&inode->i_sem);
125 file_accessed(file);
126 vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
127 vma->vm_ops = &hugetlb_vm_ops;
128
129 ret = -ENOMEM;
130 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
131 if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
132 goto out;
133
Adam Litke4c887262005-10-29 18:16:46 -0700134 ret = 0;
135 hugetlb_prefault_arch_hook(vma->vm_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 if (inode->i_size < len)
137 inode->i_size = len;
138out:
139 up(&inode->i_sem);
140
141 return ret;
142}
143
144/*
Hugh Dickins508034a2005-10-29 18:16:30 -0700145 * Called under down_write(mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 */
147
148#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
149unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
150 unsigned long len, unsigned long pgoff, unsigned long flags);
151#else
152static unsigned long
153hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
154 unsigned long len, unsigned long pgoff, unsigned long flags)
155{
156 struct mm_struct *mm = current->mm;
157 struct vm_area_struct *vma;
158 unsigned long start_addr;
159
160 if (len & ~HPAGE_MASK)
161 return -EINVAL;
162 if (len > TASK_SIZE)
163 return -ENOMEM;
164
165 if (addr) {
166 addr = ALIGN(addr, HPAGE_SIZE);
167 vma = find_vma(mm, addr);
168 if (TASK_SIZE - len >= addr &&
169 (!vma || addr + len <= vma->vm_start))
170 return addr;
171 }
172
173 start_addr = mm->free_area_cache;
174
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700175 if (len <= mm->cached_hole_size)
176 start_addr = TASK_UNMAPPED_BASE;
177
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178full_search:
179 addr = ALIGN(start_addr, HPAGE_SIZE);
180
181 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
182 /* At this point: (!vma || addr < vma->vm_end). */
183 if (TASK_SIZE - len < addr) {
184 /*
185 * Start a new search - just in case we missed
186 * some holes.
187 */
188 if (start_addr != TASK_UNMAPPED_BASE) {
189 start_addr = TASK_UNMAPPED_BASE;
190 goto full_search;
191 }
192 return -ENOMEM;
193 }
194
195 if (!vma || addr + len <= vma->vm_start)
196 return addr;
197 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
198 }
199}
200#endif
201
202/*
203 * Read a page. Again trivial. If it didn't already exist
204 * in the page cache, it is zero-filled.
205 */
206static int hugetlbfs_readpage(struct file *file, struct page * page)
207{
208 unlock_page(page);
209 return -EINVAL;
210}
211
212static int hugetlbfs_prepare_write(struct file *file,
213 struct page *page, unsigned offset, unsigned to)
214{
215 return -EINVAL;
216}
217
218static int hugetlbfs_commit_write(struct file *file,
219 struct page *page, unsigned offset, unsigned to)
220{
221 return -EINVAL;
222}
223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224static void truncate_huge_page(struct page *page)
225{
226 clear_page_dirty(page);
227 ClearPageUptodate(page);
228 remove_from_page_cache(page);
229 put_page(page);
230}
231
232static void truncate_hugepages(struct address_space *mapping, loff_t lstart)
233{
234 const pgoff_t start = lstart >> HPAGE_SHIFT;
235 struct pagevec pvec;
236 pgoff_t next;
237 int i;
238
239 pagevec_init(&pvec, 0);
240 next = start;
241 while (1) {
242 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
243 if (next == start)
244 break;
245 next = start;
246 continue;
247 }
248
249 for (i = 0; i < pagevec_count(&pvec); ++i) {
250 struct page *page = pvec.pages[i];
251
252 lock_page(page);
253 if (page->index > next)
254 next = page->index;
255 ++next;
256 truncate_huge_page(page);
257 unlock_page(page);
258 hugetlb_put_quota(mapping);
259 }
260 huge_pagevec_release(&pvec);
261 }
262 BUG_ON(!lstart && mapping->nrpages);
263}
264
265static void hugetlbfs_delete_inode(struct inode *inode)
266{
Christoph Hellwig149f4212005-10-29 18:16:43 -0700267 if (inode->i_data.nrpages)
268 truncate_hugepages(&inode->i_data, 0);
269 clear_inode(inode);
270}
271
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272static void hugetlbfs_forget_inode(struct inode *inode)
273{
Christoph Hellwig0b1533f2005-10-29 18:16:45 -0700274 struct super_block *sb = inode->i_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
Christoph Hellwig0b1533f2005-10-29 18:16:45 -0700276 if (!hlist_unhashed(&inode->i_hash)) {
277 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
278 list_move(&inode->i_list, &inode_unused);
279 inodes_stat.nr_unused++;
280 if (!sb || (sb->s_flags & MS_ACTIVE)) {
281 spin_unlock(&inode_lock);
282 return;
283 }
284 inode->i_state |= I_WILL_FREE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 spin_unlock(&inode_lock);
Christoph Hellwig0b1533f2005-10-29 18:16:45 -0700286 /*
287 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
288 * in our backing_dev_info.
289 */
290 write_inode_now(inode, 1);
291 spin_lock(&inode_lock);
292 inode->i_state &= ~I_WILL_FREE;
293 inodes_stat.nr_unused--;
294 hlist_del_init(&inode->i_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 list_del_init(&inode->i_list);
297 list_del_init(&inode->i_sb_list);
298 inode->i_state |= I_FREEING;
299 inodes_stat.nr_inodes--;
300 spin_unlock(&inode_lock);
301 if (inode->i_data.nrpages)
302 truncate_hugepages(&inode->i_data, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 clear_inode(inode);
304 destroy_inode(inode);
305}
306
307static void hugetlbfs_drop_inode(struct inode *inode)
308{
309 if (!inode->i_nlink)
Christoph Hellwig6b09b9d2005-10-29 18:16:44 -0700310 generic_delete_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 else
312 hugetlbfs_forget_inode(inode);
313}
314
315/*
316 * h_pgoff is in HPAGE_SIZE units.
317 * vma->vm_pgoff is in PAGE_SIZE units.
318 */
319static inline void
320hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
321{
322 struct vm_area_struct *vma;
323 struct prio_tree_iter iter;
324
325 vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
326 unsigned long h_vm_pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 unsigned long v_offset;
328
329 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
330 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
331 /*
332 * Is this VMA fully outside the truncation point?
333 */
334 if (h_vm_pgoff >= h_pgoff)
335 v_offset = 0;
336
Hugh Dickins508034a2005-10-29 18:16:30 -0700337 unmap_hugepage_range(vma,
338 vma->vm_start + v_offset, vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 }
340}
341
342/*
343 * Expanding truncates are not allowed.
344 */
345static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
346{
347 unsigned long pgoff;
348 struct address_space *mapping = inode->i_mapping;
349
350 if (offset > inode->i_size)
351 return -EINVAL;
352
353 BUG_ON(offset & ~HPAGE_MASK);
354 pgoff = offset >> HPAGE_SHIFT;
355
356 inode->i_size = offset;
357 spin_lock(&mapping->i_mmap_lock);
358 if (!prio_tree_empty(&mapping->i_mmap))
359 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
360 spin_unlock(&mapping->i_mmap_lock);
361 truncate_hugepages(mapping, offset);
362 return 0;
363}
364
365static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
366{
367 struct inode *inode = dentry->d_inode;
368 int error;
369 unsigned int ia_valid = attr->ia_valid;
370
371 BUG_ON(!inode);
372
373 error = inode_change_ok(inode, attr);
374 if (error)
375 goto out;
376
377 if (ia_valid & ATTR_SIZE) {
378 error = -EINVAL;
379 if (!(attr->ia_size & ~HPAGE_MASK))
380 error = hugetlb_vmtruncate(inode, attr->ia_size);
381 if (error)
382 goto out;
383 attr->ia_valid &= ~ATTR_SIZE;
384 }
385 error = inode_setattr(inode, attr);
386out:
387 return error;
388}
389
390static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
391 gid_t gid, int mode, dev_t dev)
392{
393 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
395 inode = new_inode(sb);
396 if (inode) {
397 struct hugetlbfs_inode_info *info;
398 inode->i_mode = mode;
399 inode->i_uid = uid;
400 inode->i_gid = gid;
401 inode->i_blksize = HPAGE_SIZE;
402 inode->i_blocks = 0;
403 inode->i_mapping->a_ops = &hugetlbfs_aops;
404 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
405 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
406 info = HUGETLBFS_I(inode);
407 mpol_shared_policy_init(&info->policy);
408 switch (mode & S_IFMT) {
409 default:
410 init_special_inode(inode, mode, dev);
411 break;
412 case S_IFREG:
413 inode->i_op = &hugetlbfs_inode_operations;
414 inode->i_fop = &hugetlbfs_file_operations;
415 break;
416 case S_IFDIR:
417 inode->i_op = &hugetlbfs_dir_inode_operations;
418 inode->i_fop = &simple_dir_operations;
419
420 /* directory inodes start off with i_nlink == 2 (for "." entry) */
421 inode->i_nlink++;
422 break;
423 case S_IFLNK:
424 inode->i_op = &page_symlink_inode_operations;
425 break;
426 }
427 }
428 return inode;
429}
430
431/*
432 * File creation. Allocate an inode, and we're done..
433 */
434static int hugetlbfs_mknod(struct inode *dir,
435 struct dentry *dentry, int mode, dev_t dev)
436{
437 struct inode *inode;
438 int error = -ENOSPC;
439 gid_t gid;
440
441 if (dir->i_mode & S_ISGID) {
442 gid = dir->i_gid;
443 if (S_ISDIR(mode))
444 mode |= S_ISGID;
445 } else {
446 gid = current->fsgid;
447 }
448 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
449 if (inode) {
450 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
451 d_instantiate(dentry, inode);
452 dget(dentry); /* Extra count - pin the dentry in core */
453 error = 0;
454 }
455 return error;
456}
457
458static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
459{
460 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
461 if (!retval)
462 dir->i_nlink++;
463 return retval;
464}
465
466static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
467{
468 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
469}
470
471static int hugetlbfs_symlink(struct inode *dir,
472 struct dentry *dentry, const char *symname)
473{
474 struct inode *inode;
475 int error = -ENOSPC;
476 gid_t gid;
477
478 if (dir->i_mode & S_ISGID)
479 gid = dir->i_gid;
480 else
481 gid = current->fsgid;
482
483 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
484 gid, S_IFLNK|S_IRWXUGO, 0);
485 if (inode) {
486 int l = strlen(symname)+1;
487 error = page_symlink(inode, symname, l);
488 if (!error) {
489 d_instantiate(dentry, inode);
490 dget(dentry);
491 } else
492 iput(inode);
493 }
494 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
495
496 return error;
497}
498
499/*
500 * For direct-IO reads into hugetlb pages
501 */
502static int hugetlbfs_set_page_dirty(struct page *page)
503{
504 return 0;
505}
506
507static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
508{
509 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
510
511 buf->f_type = HUGETLBFS_MAGIC;
512 buf->f_bsize = HPAGE_SIZE;
513 if (sbinfo) {
514 spin_lock(&sbinfo->stat_lock);
515 buf->f_blocks = sbinfo->max_blocks;
516 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
517 buf->f_files = sbinfo->max_inodes;
518 buf->f_ffree = sbinfo->free_inodes;
519 spin_unlock(&sbinfo->stat_lock);
520 }
521 buf->f_namelen = NAME_MAX;
522 return 0;
523}
524
525static void hugetlbfs_put_super(struct super_block *sb)
526{
527 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
528
529 if (sbi) {
530 sb->s_fs_info = NULL;
531 kfree(sbi);
532 }
533}
534
Christoph Hellwig96527982005-10-29 18:16:42 -0700535static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
536{
537 if (sbinfo->free_inodes >= 0) {
538 spin_lock(&sbinfo->stat_lock);
539 if (unlikely(!sbinfo->free_inodes)) {
540 spin_unlock(&sbinfo->stat_lock);
541 return 0;
542 }
543 sbinfo->free_inodes--;
544 spin_unlock(&sbinfo->stat_lock);
545 }
546
547 return 1;
548}
549
550static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
551{
552 if (sbinfo->free_inodes >= 0) {
553 spin_lock(&sbinfo->stat_lock);
554 sbinfo->free_inodes++;
555 spin_unlock(&sbinfo->stat_lock);
556 }
557}
558
559
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560static kmem_cache_t *hugetlbfs_inode_cachep;
561
562static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
563{
Christoph Hellwig96527982005-10-29 18:16:42 -0700564 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 struct hugetlbfs_inode_info *p;
566
Christoph Hellwig96527982005-10-29 18:16:42 -0700567 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 return NULL;
Christoph Hellwig96527982005-10-29 18:16:42 -0700569 p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
570 if (unlikely(!p)) {
571 hugetlbfs_inc_free_inodes(sbinfo);
572 return NULL;
573 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 return &p->vfs_inode;
575}
576
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577static void hugetlbfs_destroy_inode(struct inode *inode)
578{
Christoph Hellwig96527982005-10-29 18:16:42 -0700579 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
581 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
582}
583
584static struct address_space_operations hugetlbfs_aops = {
585 .readpage = hugetlbfs_readpage,
586 .prepare_write = hugetlbfs_prepare_write,
587 .commit_write = hugetlbfs_commit_write,
588 .set_page_dirty = hugetlbfs_set_page_dirty,
589};
590
Christoph Hellwig96527982005-10-29 18:16:42 -0700591
592static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
593{
594 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
595
596 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
597 SLAB_CTOR_CONSTRUCTOR)
598 inode_init_once(&ei->vfs_inode);
599}
600
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601struct file_operations hugetlbfs_file_operations = {
602 .mmap = hugetlbfs_file_mmap,
603 .fsync = simple_sync_file,
604 .get_unmapped_area = hugetlb_get_unmapped_area,
605};
606
607static struct inode_operations hugetlbfs_dir_inode_operations = {
608 .create = hugetlbfs_create,
609 .lookup = simple_lookup,
610 .link = simple_link,
611 .unlink = simple_unlink,
612 .symlink = hugetlbfs_symlink,
613 .mkdir = hugetlbfs_mkdir,
614 .rmdir = simple_rmdir,
615 .mknod = hugetlbfs_mknod,
616 .rename = simple_rename,
617 .setattr = hugetlbfs_setattr,
618};
619
620static struct inode_operations hugetlbfs_inode_operations = {
621 .setattr = hugetlbfs_setattr,
622};
623
624static struct super_operations hugetlbfs_ops = {
625 .alloc_inode = hugetlbfs_alloc_inode,
626 .destroy_inode = hugetlbfs_destroy_inode,
627 .statfs = hugetlbfs_statfs,
Christoph Hellwig149f4212005-10-29 18:16:43 -0700628 .delete_inode = hugetlbfs_delete_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 .drop_inode = hugetlbfs_drop_inode,
630 .put_super = hugetlbfs_put_super,
631};
632
633static int
634hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
635{
636 char *opt, *value, *rest;
637
638 if (!options)
639 return 0;
640 while ((opt = strsep(&options, ",")) != NULL) {
641 if (!*opt)
642 continue;
643
644 value = strchr(opt, '=');
645 if (!value || !*value)
646 return -EINVAL;
647 else
648 *value++ = '\0';
649
650 if (!strcmp(opt, "uid"))
651 pconfig->uid = simple_strtoul(value, &value, 0);
652 else if (!strcmp(opt, "gid"))
653 pconfig->gid = simple_strtoul(value, &value, 0);
654 else if (!strcmp(opt, "mode"))
655 pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
656 else if (!strcmp(opt, "size")) {
657 unsigned long long size = memparse(value, &rest);
658 if (*rest == '%') {
659 size <<= HPAGE_SHIFT;
660 size *= max_huge_pages;
661 do_div(size, 100);
662 rest++;
663 }
664 size &= HPAGE_MASK;
665 pconfig->nr_blocks = (size >> HPAGE_SHIFT);
666 value = rest;
667 } else if (!strcmp(opt,"nr_inodes")) {
668 pconfig->nr_inodes = memparse(value, &rest);
669 value = rest;
670 } else
671 return -EINVAL;
672
673 if (*value)
674 return -EINVAL;
675 }
676 return 0;
677}
678
679static int
680hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
681{
682 struct inode * inode;
683 struct dentry * root;
684 int ret;
685 struct hugetlbfs_config config;
686 struct hugetlbfs_sb_info *sbinfo;
687
688 config.nr_blocks = -1; /* No limit on size by default */
689 config.nr_inodes = -1; /* No limit on number of inodes by default */
690 config.uid = current->fsuid;
691 config.gid = current->fsgid;
692 config.mode = 0755;
693 ret = hugetlbfs_parse_options(data, &config);
694
695 if (ret)
696 return ret;
697
698 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
699 if (!sbinfo)
700 return -ENOMEM;
701 sb->s_fs_info = sbinfo;
702 spin_lock_init(&sbinfo->stat_lock);
703 sbinfo->max_blocks = config.nr_blocks;
704 sbinfo->free_blocks = config.nr_blocks;
705 sbinfo->max_inodes = config.nr_inodes;
706 sbinfo->free_inodes = config.nr_inodes;
707 sb->s_maxbytes = MAX_LFS_FILESIZE;
708 sb->s_blocksize = HPAGE_SIZE;
709 sb->s_blocksize_bits = HPAGE_SHIFT;
710 sb->s_magic = HUGETLBFS_MAGIC;
711 sb->s_op = &hugetlbfs_ops;
712 sb->s_time_gran = 1;
713 inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
714 S_IFDIR | config.mode, 0);
715 if (!inode)
716 goto out_free;
717
718 root = d_alloc_root(inode);
719 if (!root) {
720 iput(inode);
721 goto out_free;
722 }
723 sb->s_root = root;
724 return 0;
725out_free:
726 kfree(sbinfo);
727 return -ENOMEM;
728}
729
730int hugetlb_get_quota(struct address_space *mapping)
731{
732 int ret = 0;
733 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
734
735 if (sbinfo->free_blocks > -1) {
736 spin_lock(&sbinfo->stat_lock);
737 if (sbinfo->free_blocks > 0)
738 sbinfo->free_blocks--;
739 else
740 ret = -ENOMEM;
741 spin_unlock(&sbinfo->stat_lock);
742 }
743
744 return ret;
745}
746
747void hugetlb_put_quota(struct address_space *mapping)
748{
749 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
750
751 if (sbinfo->free_blocks > -1) {
752 spin_lock(&sbinfo->stat_lock);
753 sbinfo->free_blocks++;
754 spin_unlock(&sbinfo->stat_lock);
755 }
756}
757
758static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
759 int flags, const char *dev_name, void *data)
760{
761 return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
762}
763
764static struct file_system_type hugetlbfs_fs_type = {
765 .name = "hugetlbfs",
766 .get_sb = hugetlbfs_get_sb,
767 .kill_sb = kill_litter_super,
768};
769
770static struct vfsmount *hugetlbfs_vfsmount;
771
772/*
773 * Return the next identifier for a shm file
774 */
775static unsigned long hugetlbfs_counter(void)
776{
777 static DEFINE_SPINLOCK(lock);
778 static unsigned long counter;
779 unsigned long ret;
780
781 spin_lock(&lock);
782 ret = ++counter;
783 spin_unlock(&lock);
784 return ret;
785}
786
787static int can_do_hugetlb_shm(void)
788{
789 return likely(capable(CAP_IPC_LOCK) ||
790 in_group_p(sysctl_hugetlb_shm_group) ||
791 can_do_mlock());
792}
793
794struct file *hugetlb_zero_setup(size_t size)
795{
796 int error = -ENOMEM;
797 struct file *file;
798 struct inode *inode;
799 struct dentry *dentry, *root;
800 struct qstr quick_string;
801 char buf[16];
802
803 if (!can_do_hugetlb_shm())
804 return ERR_PTR(-EPERM);
805
806 if (!is_hugepage_mem_enough(size))
807 return ERR_PTR(-ENOMEM);
808
809 if (!user_shm_lock(size, current->user))
810 return ERR_PTR(-ENOMEM);
811
812 root = hugetlbfs_vfsmount->mnt_root;
813 snprintf(buf, 16, "%lu", hugetlbfs_counter());
814 quick_string.name = buf;
815 quick_string.len = strlen(quick_string.name);
816 quick_string.hash = 0;
817 dentry = d_alloc(root, &quick_string);
818 if (!dentry)
819 goto out_shm_unlock;
820
821 error = -ENFILE;
822 file = get_empty_filp();
823 if (!file)
824 goto out_dentry;
825
826 error = -ENOSPC;
827 inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
828 current->fsgid, S_IFREG | S_IRWXUGO, 0);
829 if (!inode)
830 goto out_file;
831
832 d_instantiate(dentry, inode);
833 inode->i_size = size;
834 inode->i_nlink = 0;
835 file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
836 file->f_dentry = dentry;
837 file->f_mapping = inode->i_mapping;
838 file->f_op = &hugetlbfs_file_operations;
839 file->f_mode = FMODE_WRITE | FMODE_READ;
840 return file;
841
842out_file:
843 put_filp(file);
844out_dentry:
845 dput(dentry);
846out_shm_unlock:
847 user_shm_unlock(size, current->user);
848 return ERR_PTR(error);
849}
850
851static int __init init_hugetlbfs_fs(void)
852{
853 int error;
854 struct vfsmount *vfsmount;
855
856 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
857 sizeof(struct hugetlbfs_inode_info),
858 0, 0, init_once, NULL);
859 if (hugetlbfs_inode_cachep == NULL)
860 return -ENOMEM;
861
862 error = register_filesystem(&hugetlbfs_fs_type);
863 if (error)
864 goto out;
865
866 vfsmount = kern_mount(&hugetlbfs_fs_type);
867
868 if (!IS_ERR(vfsmount)) {
869 hugetlbfs_vfsmount = vfsmount;
870 return 0;
871 }
872
873 error = PTR_ERR(vfsmount);
874
875 out:
876 if (error)
877 kmem_cache_destroy(hugetlbfs_inode_cachep);
878 return error;
879}
880
881static void __exit exit_hugetlbfs_fs(void)
882{
883 kmem_cache_destroy(hugetlbfs_inode_cachep);
884 unregister_filesystem(&hugetlbfs_fs_type);
885}
886
887module_init(init_hugetlbfs_fs)
888module_exit(exit_hugetlbfs_fs)
889
890MODULE_LICENSE("GPL");