blob: 882053031aa0590b502551783c8902b50461abf1 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Resizable virtual memory filesystem for Linux.
3 *
4 * Copyright (C) 2000 Linus Torvalds.
5 * 2000 Transmeta Corp.
6 * 2000-2001 Christoph Rohland
7 * 2000-2001 SAP AG
8 * 2002 Red Hat Inc.
Hugh Dickins0edd73b2005-06-21 17:15:04 -07009 * Copyright (C) 2002-2005 Hugh Dickins.
10 * Copyright (C) 2002-2005 VERITAS Software Corporation.
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * Copyright (C) 2004 Andi Kleen, SuSE Labs
12 *
13 * Extended attribute support for tmpfs:
14 * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
15 * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
16 *
17 * This file is released under the GPL.
18 */
19
20/*
21 * This virtual memory filesystem is heavily based on the ramfs. It
22 * extends ramfs by the ability to use swap and honor resource limits
23 * which makes it a completely usable filesystem.
24 */
25
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/module.h>
27#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/fs.h>
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070029#include <linux/xattr.h>
30#include <linux/generic_acl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/mm.h>
32#include <linux/mman.h>
33#include <linux/file.h>
34#include <linux/swap.h>
35#include <linux/pagemap.h>
36#include <linux/string.h>
37#include <linux/slab.h>
38#include <linux/backing-dev.h>
39#include <linux/shmem_fs.h>
40#include <linux/mount.h>
41#include <linux/writeback.h>
42#include <linux/vfs.h>
43#include <linux/blkdev.h>
44#include <linux/security.h>
45#include <linux/swapops.h>
46#include <linux/mempolicy.h>
47#include <linux/namei.h>
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +000048#include <linux/ctype.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070049#include <linux/migrate.h>
Christoph Lameterc1f60a52006-09-25 23:31:11 -070050#include <linux/highmem.h>
Andrew Morton3fcfab12006-10-19 23:28:16 -070051#include <linux/backing-dev.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070052
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#include <asm/uaccess.h>
54#include <asm/div64.h>
55#include <asm/pgtable.h>
56
57/* This magic number is used in glibc for posix shared memory */
58#define TMPFS_MAGIC 0x01021994
59
60#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
61#define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
62#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
63
64#define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
65#define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT)
66
67#define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
68
69/* info->flags needs VM_flags to handle pagein/truncate races efficiently */
70#define SHMEM_PAGEIN VM_READ
71#define SHMEM_TRUNCATE VM_WRITE
72
73/* Definition to limit shmem_truncate's steps between cond_rescheds */
74#define LATENCY_LIMIT 64
75
76/* Pretend that each entry is of this size in directory's i_size */
77#define BOGO_DIRENT_SIZE 20
78
Linus Torvalds1da177e2005-04-16 15:20:36 -070079/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
80enum sgp_type {
81 SGP_QUICK, /* don't try more than file page cache lookup */
82 SGP_READ, /* don't exceed i_size, don't allocate page */
83 SGP_CACHE, /* don't exceed i_size, may allocate page */
84 SGP_WRITE, /* may exceed i_size, may allocate page */
85};
86
87static int shmem_getpage(struct inode *inode, unsigned long idx,
88 struct page **pagep, enum sgp_type sgp, int *type);
89
Al Viro6daa0e22005-10-21 03:18:50 -040090static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -070091{
92 /*
93 * The above definition of ENTRIES_PER_PAGE, and the use of
94 * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
95 * might be reconsidered if it ever diverges from PAGE_SIZE.
96 */
97 return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT);
98}
99
100static inline void shmem_dir_free(struct page *page)
101{
102 __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT);
103}
104
105static struct page **shmem_dir_map(struct page *page)
106{
107 return (struct page **)kmap_atomic(page, KM_USER0);
108}
109
110static inline void shmem_dir_unmap(struct page **dir)
111{
112 kunmap_atomic(dir, KM_USER0);
113}
114
115static swp_entry_t *shmem_swp_map(struct page *page)
116{
117 return (swp_entry_t *)kmap_atomic(page, KM_USER1);
118}
119
120static inline void shmem_swp_balance_unmap(void)
121{
122 /*
123 * When passing a pointer to an i_direct entry, to code which
124 * also handles indirect entries and so will shmem_swp_unmap,
125 * we must arrange for the preempt count to remain in balance.
126 * What kmap_atomic of a lowmem page does depends on config
127 * and architecture, so pretend to kmap_atomic some lowmem page.
128 */
129 (void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
130}
131
132static inline void shmem_swp_unmap(swp_entry_t *entry)
133{
134 kunmap_atomic(entry, KM_USER1);
135}
136
137static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
138{
139 return sb->s_fs_info;
140}
141
142/*
143 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
144 * for shared memory and for shared anonymous (/dev/zero) mappings
145 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
146 * consistent with the pre-accounting of private mappings ...
147 */
148static inline int shmem_acct_size(unsigned long flags, loff_t size)
149{
150 return (flags & VM_ACCOUNT)?
151 security_vm_enough_memory(VM_ACCT(size)): 0;
152}
153
154static inline void shmem_unacct_size(unsigned long flags, loff_t size)
155{
156 if (flags & VM_ACCOUNT)
157 vm_unacct_memory(VM_ACCT(size));
158}
159
160/*
161 * ... whereas tmpfs objects are accounted incrementally as
162 * pages are allocated, in order to allow huge sparse files.
163 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
164 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
165 */
166static inline int shmem_acct_block(unsigned long flags)
167{
168 return (flags & VM_ACCOUNT)?
169 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE));
170}
171
172static inline void shmem_unacct_blocks(unsigned long flags, long pages)
173{
174 if (!(flags & VM_ACCOUNT))
175 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
176}
177
178static struct super_operations shmem_ops;
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700179static const struct address_space_operations shmem_aops;
Helge Deller15ad7cd2006-12-06 20:40:36 -0800180static const struct file_operations shmem_file_operations;
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800181static const struct inode_operations shmem_inode_operations;
182static const struct inode_operations shmem_dir_inode_operations;
183static const struct inode_operations shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184static struct vm_operations_struct shmem_vm_ops;
185
Ravikiran G Thirumalai6c231b72005-09-06 15:17:45 -0700186static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 .ra_pages = 0, /* No readahead */
188 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
189 .unplug_io_fn = default_unplug_io_fn,
190};
191
192static LIST_HEAD(shmem_swaplist);
193static DEFINE_SPINLOCK(shmem_swaplist_lock);
194
195static void shmem_free_blocks(struct inode *inode, long pages)
196{
197 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700198 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 spin_lock(&sbinfo->stat_lock);
200 sbinfo->free_blocks += pages;
201 inode->i_blocks -= pages*BLOCKS_PER_PAGE;
202 spin_unlock(&sbinfo->stat_lock);
203 }
204}
205
206/*
207 * shmem_recalc_inode - recalculate the size of an inode
208 *
209 * @inode: inode to recalc
210 *
211 * We have to calculate the free blocks since the mm can drop
212 * undirtied hole pages behind our back.
213 *
214 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
215 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
216 *
217 * It has to be called with the spinlock held.
218 */
219static void shmem_recalc_inode(struct inode *inode)
220{
221 struct shmem_inode_info *info = SHMEM_I(inode);
222 long freed;
223
224 freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
225 if (freed > 0) {
226 info->alloced -= freed;
227 shmem_unacct_blocks(info->flags, freed);
228 shmem_free_blocks(inode, freed);
229 }
230}
231
232/*
233 * shmem_swp_entry - find the swap vector position in the info structure
234 *
235 * @info: info structure for the inode
236 * @index: index of the page to find
237 * @page: optional page to add to the structure. Has to be preset to
238 * all zeros
239 *
240 * If there is no space allocated yet it will return NULL when
241 * page is NULL, else it will use the page for the needed block,
242 * setting it to NULL on return to indicate that it has been used.
243 *
244 * The swap vector is organized the following way:
245 *
246 * There are SHMEM_NR_DIRECT entries directly stored in the
247 * shmem_inode_info structure. So small files do not need an addional
248 * allocation.
249 *
250 * For pages with index > SHMEM_NR_DIRECT there is the pointer
251 * i_indirect which points to a page which holds in the first half
252 * doubly indirect blocks, in the second half triple indirect blocks:
253 *
254 * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the
255 * following layout (for SHMEM_NR_DIRECT == 16):
256 *
257 * i_indirect -> dir --> 16-19
258 * | +-> 20-23
259 * |
260 * +-->dir2 --> 24-27
261 * | +-> 28-31
262 * | +-> 32-35
263 * | +-> 36-39
264 * |
265 * +-->dir3 --> 40-43
266 * +-> 44-47
267 * +-> 48-51
268 * +-> 52-55
269 */
270static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page)
271{
272 unsigned long offset;
273 struct page **dir;
274 struct page *subdir;
275
276 if (index < SHMEM_NR_DIRECT) {
277 shmem_swp_balance_unmap();
278 return info->i_direct+index;
279 }
280 if (!info->i_indirect) {
281 if (page) {
282 info->i_indirect = *page;
283 *page = NULL;
284 }
285 return NULL; /* need another page */
286 }
287
288 index -= SHMEM_NR_DIRECT;
289 offset = index % ENTRIES_PER_PAGE;
290 index /= ENTRIES_PER_PAGE;
291 dir = shmem_dir_map(info->i_indirect);
292
293 if (index >= ENTRIES_PER_PAGE/2) {
294 index -= ENTRIES_PER_PAGE/2;
295 dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE;
296 index %= ENTRIES_PER_PAGE;
297 subdir = *dir;
298 if (!subdir) {
299 if (page) {
300 *dir = *page;
301 *page = NULL;
302 }
303 shmem_dir_unmap(dir);
304 return NULL; /* need another page */
305 }
306 shmem_dir_unmap(dir);
307 dir = shmem_dir_map(subdir);
308 }
309
310 dir += index;
311 subdir = *dir;
312 if (!subdir) {
313 if (!page || !(subdir = *page)) {
314 shmem_dir_unmap(dir);
315 return NULL; /* need a page */
316 }
317 *dir = subdir;
318 *page = NULL;
319 }
320 shmem_dir_unmap(dir);
321 return shmem_swp_map(subdir) + offset;
322}
323
324static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
325{
326 long incdec = value? 1: -1;
327
328 entry->val = value;
329 info->swapped += incdec;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700330 if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
331 struct page *page = kmap_atomic_to_page(entry);
332 set_page_private(page, page_private(page) + incdec);
333 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334}
335
336/*
337 * shmem_swp_alloc - get the position of the swap entry for the page.
338 * If it does not exist allocate the entry.
339 *
340 * @info: info structure for the inode
341 * @index: index of the page to find
342 * @sgp: check and recheck i_size? skip allocation?
343 */
344static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp)
345{
346 struct inode *inode = &info->vfs_inode;
347 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
348 struct page *page = NULL;
349 swp_entry_t *entry;
350
351 if (sgp != SGP_WRITE &&
352 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
353 return ERR_PTR(-EINVAL);
354
355 while (!(entry = shmem_swp_entry(info, index, &page))) {
356 if (sgp == SGP_READ)
357 return shmem_swp_map(ZERO_PAGE(0));
358 /*
359 * Test free_blocks against 1 not 0, since we have 1 data
360 * page (and perhaps indirect index pages) yet to allocate:
361 * a waste to allocate index if we cannot allocate data.
362 */
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700363 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 spin_lock(&sbinfo->stat_lock);
365 if (sbinfo->free_blocks <= 1) {
366 spin_unlock(&sbinfo->stat_lock);
367 return ERR_PTR(-ENOSPC);
368 }
369 sbinfo->free_blocks--;
370 inode->i_blocks += BLOCKS_PER_PAGE;
371 spin_unlock(&sbinfo->stat_lock);
372 }
373
374 spin_unlock(&info->lock);
375 page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700376 if (page)
377 set_page_private(page, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 spin_lock(&info->lock);
379
380 if (!page) {
381 shmem_free_blocks(inode, 1);
382 return ERR_PTR(-ENOMEM);
383 }
384 if (sgp != SGP_WRITE &&
385 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
386 entry = ERR_PTR(-EINVAL);
387 break;
388 }
389 if (info->next_index <= index)
390 info->next_index = index + 1;
391 }
392 if (page) {
393 /* another task gave its page, or truncated the file */
394 shmem_free_blocks(inode, 1);
395 shmem_dir_free(page);
396 }
397 if (info->next_index <= index && !IS_ERR(entry))
398 info->next_index = index + 1;
399 return entry;
400}
401
402/*
403 * shmem_free_swp - free some swap entries in a directory
404 *
405 * @dir: pointer to the directory
406 * @edir: pointer after last entry of the directory
407 */
408static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir)
409{
410 swp_entry_t *ptr;
411 int freed = 0;
412
413 for (ptr = dir; ptr < edir; ptr++) {
414 if (ptr->val) {
415 free_swap_and_cache(*ptr);
416 *ptr = (swp_entry_t){0};
417 freed++;
418 }
419 }
420 return freed;
421}
422
423static int shmem_map_and_free_swp(struct page *subdir,
424 int offset, int limit, struct page ***dir)
425{
426 swp_entry_t *ptr;
427 int freed = 0;
428
429 ptr = shmem_swp_map(subdir);
430 for (; offset < limit; offset += LATENCY_LIMIT) {
431 int size = limit - offset;
432 if (size > LATENCY_LIMIT)
433 size = LATENCY_LIMIT;
434 freed += shmem_free_swp(ptr+offset, ptr+offset+size);
435 if (need_resched()) {
436 shmem_swp_unmap(ptr);
437 if (*dir) {
438 shmem_dir_unmap(*dir);
439 *dir = NULL;
440 }
441 cond_resched();
442 ptr = shmem_swp_map(subdir);
443 }
444 }
445 shmem_swp_unmap(ptr);
446 return freed;
447}
448
449static void shmem_free_pages(struct list_head *next)
450{
451 struct page *page;
452 int freed = 0;
453
454 do {
455 page = container_of(next, struct page, lru);
456 next = next->next;
457 shmem_dir_free(page);
458 freed++;
459 if (freed >= LATENCY_LIMIT) {
460 cond_resched();
461 freed = 0;
462 }
463 } while (next);
464}
465
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800466static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467{
468 struct shmem_inode_info *info = SHMEM_I(inode);
469 unsigned long idx;
470 unsigned long size;
471 unsigned long limit;
472 unsigned long stage;
473 unsigned long diroff;
474 struct page **dir;
475 struct page *topdir;
476 struct page *middir;
477 struct page *subdir;
478 swp_entry_t *ptr;
479 LIST_HEAD(pages_to_free);
480 long nr_pages_to_free = 0;
481 long nr_swaps_freed = 0;
482 int offset;
483 int freed;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800484 int punch_hole = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485
486 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800487 idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 if (idx >= info->next_index)
489 return;
490
491 spin_lock(&info->lock);
492 info->flags |= SHMEM_TRUNCATE;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800493 if (likely(end == (loff_t) -1)) {
494 limit = info->next_index;
495 info->next_index = idx;
496 } else {
497 limit = (end + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
498 if (limit > info->next_index)
499 limit = info->next_index;
500 punch_hole = 1;
501 }
502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 topdir = info->i_indirect;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800504 if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 info->i_indirect = NULL;
506 nr_pages_to_free++;
507 list_add(&topdir->lru, &pages_to_free);
508 }
509 spin_unlock(&info->lock);
510
511 if (info->swapped && idx < SHMEM_NR_DIRECT) {
512 ptr = info->i_direct;
513 size = limit;
514 if (size > SHMEM_NR_DIRECT)
515 size = SHMEM_NR_DIRECT;
516 nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size);
517 }
Badari Pulavarty92a3d032006-12-22 01:06:23 -0800518
519 /*
520 * If there are no indirect blocks or we are punching a hole
521 * below indirect blocks, nothing to be done.
522 */
523 if (!topdir || (punch_hole && (limit <= SHMEM_NR_DIRECT)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 goto done2;
525
526 BUG_ON(limit <= SHMEM_NR_DIRECT);
527 limit -= SHMEM_NR_DIRECT;
528 idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
529 offset = idx % ENTRIES_PER_PAGE;
530 idx -= offset;
531
532 dir = shmem_dir_map(topdir);
533 stage = ENTRIES_PER_PAGEPAGE/2;
534 if (idx < ENTRIES_PER_PAGEPAGE/2) {
535 middir = topdir;
536 diroff = idx/ENTRIES_PER_PAGE;
537 } else {
538 dir += ENTRIES_PER_PAGE/2;
539 dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
540 while (stage <= idx)
541 stage += ENTRIES_PER_PAGEPAGE;
542 middir = *dir;
543 if (*dir) {
544 diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
545 ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
546 if (!diroff && !offset) {
547 *dir = NULL;
548 nr_pages_to_free++;
549 list_add(&middir->lru, &pages_to_free);
550 }
551 shmem_dir_unmap(dir);
552 dir = shmem_dir_map(middir);
553 } else {
554 diroff = 0;
555 offset = 0;
556 idx = stage;
557 }
558 }
559
560 for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
561 if (unlikely(idx == stage)) {
562 shmem_dir_unmap(dir);
563 dir = shmem_dir_map(topdir) +
564 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
565 while (!*dir) {
566 dir++;
567 idx += ENTRIES_PER_PAGEPAGE;
568 if (idx >= limit)
569 goto done1;
570 }
571 stage = idx + ENTRIES_PER_PAGEPAGE;
572 middir = *dir;
573 *dir = NULL;
574 nr_pages_to_free++;
575 list_add(&middir->lru, &pages_to_free);
576 shmem_dir_unmap(dir);
577 cond_resched();
578 dir = shmem_dir_map(middir);
579 diroff = 0;
580 }
581 subdir = dir[diroff];
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700582 if (subdir && page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 size = limit - idx;
584 if (size > ENTRIES_PER_PAGE)
585 size = ENTRIES_PER_PAGE;
586 freed = shmem_map_and_free_swp(subdir,
587 offset, size, &dir);
588 if (!dir)
589 dir = shmem_dir_map(middir);
590 nr_swaps_freed += freed;
591 if (offset)
592 spin_lock(&info->lock);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700593 set_page_private(subdir, page_private(subdir) - freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 if (offset)
595 spin_unlock(&info->lock);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800596 if (!punch_hole)
597 BUG_ON(page_private(subdir) > offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 }
599 if (offset)
600 offset = 0;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800601 else if (subdir && !page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 dir[diroff] = NULL;
603 nr_pages_to_free++;
604 list_add(&subdir->lru, &pages_to_free);
605 }
606 }
607done1:
608 shmem_dir_unmap(dir);
609done2:
610 if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
611 /*
612 * Call truncate_inode_pages again: racing shmem_unuse_inode
613 * may have swizzled a page in from swap since vmtruncate or
614 * generic_delete_inode did it, before we lowered next_index.
615 * Also, though shmem_getpage checks i_size before adding to
616 * cache, no recheck after: so fix the narrow window there too.
617 */
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800618 truncate_inode_pages_range(inode->i_mapping, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 }
620
621 spin_lock(&info->lock);
622 info->flags &= ~SHMEM_TRUNCATE;
623 info->swapped -= nr_swaps_freed;
624 if (nr_pages_to_free)
625 shmem_free_blocks(inode, nr_pages_to_free);
626 shmem_recalc_inode(inode);
627 spin_unlock(&info->lock);
628
629 /*
630 * Empty swap vector directory pages to be freed?
631 */
632 if (!list_empty(&pages_to_free)) {
633 pages_to_free.prev->next = NULL;
634 shmem_free_pages(pages_to_free.next);
635 }
636}
637
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800638static void shmem_truncate(struct inode *inode)
639{
640 shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
641}
642
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
644{
645 struct inode *inode = dentry->d_inode;
646 struct page *page = NULL;
647 int error;
648
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700649 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 if (attr->ia_size < inode->i_size) {
651 /*
652 * If truncating down to a partial page, then
653 * if that page is already allocated, hold it
654 * in memory until the truncation is over, so
655 * truncate_partial_page cannnot miss it were
656 * it assigned to swap.
657 */
658 if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
659 (void) shmem_getpage(inode,
660 attr->ia_size>>PAGE_CACHE_SHIFT,
661 &page, SGP_READ, NULL);
662 }
663 /*
664 * Reset SHMEM_PAGEIN flag so that shmem_truncate can
665 * detect if any pages might have been added to cache
666 * after truncate_inode_pages. But we needn't bother
667 * if it's being fully truncated to zero-length: the
668 * nrpages check is efficient enough in that case.
669 */
670 if (attr->ia_size) {
671 struct shmem_inode_info *info = SHMEM_I(inode);
672 spin_lock(&info->lock);
673 info->flags &= ~SHMEM_PAGEIN;
674 spin_unlock(&info->lock);
675 }
676 }
677 }
678
679 error = inode_change_ok(inode, attr);
680 if (!error)
681 error = inode_setattr(inode, attr);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700682#ifdef CONFIG_TMPFS_POSIX_ACL
683 if (!error && (attr->ia_valid & ATTR_MODE))
684 error = generic_acl_chmod(inode, &shmem_acl_ops);
685#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 if (page)
687 page_cache_release(page);
688 return error;
689}
690
691static void shmem_delete_inode(struct inode *inode)
692{
693 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
694 struct shmem_inode_info *info = SHMEM_I(inode);
695
696 if (inode->i_op->truncate == shmem_truncate) {
Mark Fashehfef26652005-09-09 13:01:31 -0700697 truncate_inode_pages(inode->i_mapping, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 shmem_unacct_size(info->flags, inode->i_size);
699 inode->i_size = 0;
700 shmem_truncate(inode);
701 if (!list_empty(&info->swaplist)) {
702 spin_lock(&shmem_swaplist_lock);
703 list_del_init(&info->swaplist);
704 spin_unlock(&shmem_swaplist_lock);
705 }
706 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700707 BUG_ON(inode->i_blocks);
708 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 spin_lock(&sbinfo->stat_lock);
710 sbinfo->free_inodes++;
711 spin_unlock(&sbinfo->stat_lock);
712 }
713 clear_inode(inode);
714}
715
716static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
717{
718 swp_entry_t *ptr;
719
720 for (ptr = dir; ptr < edir; ptr++) {
721 if (ptr->val == entry.val)
722 return ptr - dir;
723 }
724 return -1;
725}
726
727static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
728{
729 struct inode *inode;
730 unsigned long idx;
731 unsigned long size;
732 unsigned long limit;
733 unsigned long stage;
734 struct page **dir;
735 struct page *subdir;
736 swp_entry_t *ptr;
737 int offset;
738
739 idx = 0;
740 ptr = info->i_direct;
741 spin_lock(&info->lock);
742 limit = info->next_index;
743 size = limit;
744 if (size > SHMEM_NR_DIRECT)
745 size = SHMEM_NR_DIRECT;
746 offset = shmem_find_swp(entry, ptr, ptr+size);
747 if (offset >= 0) {
748 shmem_swp_balance_unmap();
749 goto found;
750 }
751 if (!info->i_indirect)
752 goto lost2;
753
754 dir = shmem_dir_map(info->i_indirect);
755 stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
756
757 for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
758 if (unlikely(idx == stage)) {
759 shmem_dir_unmap(dir-1);
760 dir = shmem_dir_map(info->i_indirect) +
761 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
762 while (!*dir) {
763 dir++;
764 idx += ENTRIES_PER_PAGEPAGE;
765 if (idx >= limit)
766 goto lost1;
767 }
768 stage = idx + ENTRIES_PER_PAGEPAGE;
769 subdir = *dir;
770 shmem_dir_unmap(dir);
771 dir = shmem_dir_map(subdir);
772 }
773 subdir = *dir;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700774 if (subdir && page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 ptr = shmem_swp_map(subdir);
776 size = limit - idx;
777 if (size > ENTRIES_PER_PAGE)
778 size = ENTRIES_PER_PAGE;
779 offset = shmem_find_swp(entry, ptr, ptr+size);
780 if (offset >= 0) {
781 shmem_dir_unmap(dir);
782 goto found;
783 }
784 shmem_swp_unmap(ptr);
785 }
786 }
787lost1:
788 shmem_dir_unmap(dir-1);
789lost2:
790 spin_unlock(&info->lock);
791 return 0;
792found:
793 idx += offset;
794 inode = &info->vfs_inode;
795 if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) {
796 info->flags |= SHMEM_PAGEIN;
797 shmem_swp_set(info, ptr + offset, 0);
798 }
799 shmem_swp_unmap(ptr);
800 spin_unlock(&info->lock);
801 /*
802 * Decrement swap count even when the entry is left behind:
803 * try_to_unuse will skip over mms, then reincrement count.
804 */
805 swap_free(entry);
806 return 1;
807}
808
809/*
810 * shmem_unuse() search for an eventually swapped out shmem page.
811 */
812int shmem_unuse(swp_entry_t entry, struct page *page)
813{
814 struct list_head *p, *next;
815 struct shmem_inode_info *info;
816 int found = 0;
817
818 spin_lock(&shmem_swaplist_lock);
819 list_for_each_safe(p, next, &shmem_swaplist) {
820 info = list_entry(p, struct shmem_inode_info, swaplist);
821 if (!info->swapped)
822 list_del_init(&info->swaplist);
823 else if (shmem_unuse_inode(info, entry, page)) {
824 /* move head to start search for next from here */
825 list_move_tail(&shmem_swaplist, &info->swaplist);
826 found = 1;
827 break;
828 }
829 }
830 spin_unlock(&shmem_swaplist_lock);
831 return found;
832}
833
834/*
835 * Move the page from the page cache to the swap cache.
836 */
837static int shmem_writepage(struct page *page, struct writeback_control *wbc)
838{
839 struct shmem_inode_info *info;
840 swp_entry_t *entry, swap;
841 struct address_space *mapping;
842 unsigned long index;
843 struct inode *inode;
844
845 BUG_ON(!PageLocked(page));
846 BUG_ON(page_mapped(page));
847
848 mapping = page->mapping;
849 index = page->index;
850 inode = mapping->host;
851 info = SHMEM_I(inode);
852 if (info->flags & VM_LOCKED)
853 goto redirty;
854 swap = get_swap_page();
855 if (!swap.val)
856 goto redirty;
857
858 spin_lock(&info->lock);
859 shmem_recalc_inode(inode);
860 if (index >= info->next_index) {
861 BUG_ON(!(info->flags & SHMEM_TRUNCATE));
862 goto unlock;
863 }
864 entry = shmem_swp_entry(info, index, NULL);
865 BUG_ON(!entry);
866 BUG_ON(entry->val);
867
868 if (move_to_swap_cache(page, swap) == 0) {
869 shmem_swp_set(info, entry, swap.val);
870 shmem_swp_unmap(entry);
871 spin_unlock(&info->lock);
872 if (list_empty(&info->swaplist)) {
873 spin_lock(&shmem_swaplist_lock);
874 /* move instead of add in case we're racing */
875 list_move_tail(&info->swaplist, &shmem_swaplist);
876 spin_unlock(&shmem_swaplist_lock);
877 }
878 unlock_page(page);
879 return 0;
880 }
881
882 shmem_swp_unmap(entry);
883unlock:
884 spin_unlock(&info->lock);
885 swap_free(swap);
886redirty:
887 set_page_dirty(page);
Zach Brown994fc28c2005-12-15 14:28:17 -0800888 return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889}
890
891#ifdef CONFIG_NUMA
Hugh Dickinsd15c0232006-03-22 00:08:46 -0800892static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +0000893{
894 char *nodelist = strchr(value, ':');
895 int err = 1;
896
897 if (nodelist) {
898 /* NUL-terminate policy string */
899 *nodelist++ = '\0';
900 if (nodelist_parse(nodelist, *policy_nodes))
901 goto out;
902 }
903 if (!strcmp(value, "default")) {
904 *policy = MPOL_DEFAULT;
905 /* Don't allow a nodelist */
906 if (!nodelist)
907 err = 0;
908 } else if (!strcmp(value, "prefer")) {
909 *policy = MPOL_PREFERRED;
910 /* Insist on a nodelist of one node only */
911 if (nodelist) {
912 char *rest = nodelist;
913 while (isdigit(*rest))
914 rest++;
915 if (!*rest)
916 err = 0;
917 }
918 } else if (!strcmp(value, "bind")) {
919 *policy = MPOL_BIND;
920 /* Insist on a nodelist */
921 if (nodelist)
922 err = 0;
923 } else if (!strcmp(value, "interleave")) {
924 *policy = MPOL_INTERLEAVE;
925 /* Default to nodes online if no nodelist */
926 if (!nodelist)
927 *policy_nodes = node_online_map;
928 err = 0;
929 }
930out:
931 /* Restore string for error message */
932 if (nodelist)
933 *--nodelist = ':';
934 return err;
935}
936
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937static struct page *shmem_swapin_async(struct shared_policy *p,
938 swp_entry_t entry, unsigned long idx)
939{
940 struct page *page;
941 struct vm_area_struct pvma;
942
943 /* Create a pseudo vma that just contains the policy */
944 memset(&pvma, 0, sizeof(struct vm_area_struct));
945 pvma.vm_end = PAGE_SIZE;
946 pvma.vm_pgoff = idx;
947 pvma.vm_policy = mpol_shared_policy_lookup(p, idx);
948 page = read_swap_cache_async(entry, &pvma, 0);
949 mpol_free(pvma.vm_policy);
950 return page;
951}
952
953struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry,
954 unsigned long idx)
955{
956 struct shared_policy *p = &info->policy;
957 int i, num;
958 struct page *page;
959 unsigned long offset;
960
961 num = valid_swaphandles(entry, &offset);
962 for (i = 0; i < num; offset++, i++) {
963 page = shmem_swapin_async(p,
964 swp_entry(swp_type(entry), offset), idx);
965 if (!page)
966 break;
967 page_cache_release(page);
968 }
969 lru_add_drain(); /* Push any new pages onto the LRU now */
970 return shmem_swapin_async(p, entry, idx);
971}
972
973static struct page *
Al Viro6daa0e22005-10-21 03:18:50 -0400974shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 unsigned long idx)
976{
977 struct vm_area_struct pvma;
978 struct page *page;
979
980 memset(&pvma, 0, sizeof(struct vm_area_struct));
981 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
982 pvma.vm_pgoff = idx;
983 pvma.vm_end = PAGE_SIZE;
984 page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0);
985 mpol_free(pvma.vm_policy);
986 return page;
987}
988#else
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +0000989static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
990{
991 return 1;
992}
993
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994static inline struct page *
995shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
996{
997 swapin_readahead(entry, 0, NULL);
998 return read_swap_cache_async(entry, NULL, 0);
999}
1000
1001static inline struct page *
Al Virodd0fc662005-10-07 07:46:04 +01001002shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003{
1004 return alloc_page(gfp | __GFP_ZERO);
1005}
1006#endif
1007
1008/*
1009 * shmem_getpage - either get the page from swap or allocate a new one
1010 *
1011 * If we allocate a new one we do not mark it dirty. That's up to the
1012 * vm. If we swap it in we mark it dirty since we also free the swap
1013 * entry since a page cannot live in both the swap and page cache
1014 */
1015static int shmem_getpage(struct inode *inode, unsigned long idx,
1016 struct page **pagep, enum sgp_type sgp, int *type)
1017{
1018 struct address_space *mapping = inode->i_mapping;
1019 struct shmem_inode_info *info = SHMEM_I(inode);
1020 struct shmem_sb_info *sbinfo;
1021 struct page *filepage = *pagep;
1022 struct page *swappage;
1023 swp_entry_t *entry;
1024 swp_entry_t swap;
1025 int error;
1026
1027 if (idx >= SHMEM_MAX_INDEX)
1028 return -EFBIG;
1029 /*
1030 * Normally, filepage is NULL on entry, and either found
1031 * uptodate immediately, or allocated and zeroed, or read
1032 * in under swappage, which is then assigned to filepage.
1033 * But shmem_prepare_write passes in a locked filepage,
1034 * which may be found not uptodate by other callers too,
1035 * and may need to be copied from the swappage read in.
1036 */
1037repeat:
1038 if (!filepage)
1039 filepage = find_lock_page(mapping, idx);
1040 if (filepage && PageUptodate(filepage))
1041 goto done;
1042 error = 0;
1043 if (sgp == SGP_QUICK)
1044 goto failed;
1045
1046 spin_lock(&info->lock);
1047 shmem_recalc_inode(inode);
1048 entry = shmem_swp_alloc(info, idx, sgp);
1049 if (IS_ERR(entry)) {
1050 spin_unlock(&info->lock);
1051 error = PTR_ERR(entry);
1052 goto failed;
1053 }
1054 swap = *entry;
1055
1056 if (swap.val) {
1057 /* Look it up and read it in.. */
1058 swappage = lookup_swap_cache(swap);
1059 if (!swappage) {
1060 shmem_swp_unmap(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 /* here we actually do the io */
1062 if (type && *type == VM_FAULT_MINOR) {
Christoph Lameterf8891e52006-06-30 01:55:45 -07001063 __count_vm_event(PGMAJFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 *type = VM_FAULT_MAJOR;
1065 }
Christoph Lameterf8891e52006-06-30 01:55:45 -07001066 spin_unlock(&info->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 swappage = shmem_swapin(info, swap, idx);
1068 if (!swappage) {
1069 spin_lock(&info->lock);
1070 entry = shmem_swp_alloc(info, idx, sgp);
1071 if (IS_ERR(entry))
1072 error = PTR_ERR(entry);
1073 else {
1074 if (entry->val == swap.val)
1075 error = -ENOMEM;
1076 shmem_swp_unmap(entry);
1077 }
1078 spin_unlock(&info->lock);
1079 if (error)
1080 goto failed;
1081 goto repeat;
1082 }
1083 wait_on_page_locked(swappage);
1084 page_cache_release(swappage);
1085 goto repeat;
1086 }
1087
1088 /* We have to do this with page locked to prevent races */
1089 if (TestSetPageLocked(swappage)) {
1090 shmem_swp_unmap(entry);
1091 spin_unlock(&info->lock);
1092 wait_on_page_locked(swappage);
1093 page_cache_release(swappage);
1094 goto repeat;
1095 }
1096 if (PageWriteback(swappage)) {
1097 shmem_swp_unmap(entry);
1098 spin_unlock(&info->lock);
1099 wait_on_page_writeback(swappage);
1100 unlock_page(swappage);
1101 page_cache_release(swappage);
1102 goto repeat;
1103 }
1104 if (!PageUptodate(swappage)) {
1105 shmem_swp_unmap(entry);
1106 spin_unlock(&info->lock);
1107 unlock_page(swappage);
1108 page_cache_release(swappage);
1109 error = -EIO;
1110 goto failed;
1111 }
1112
1113 if (filepage) {
1114 shmem_swp_set(info, entry, 0);
1115 shmem_swp_unmap(entry);
1116 delete_from_swap_cache(swappage);
1117 spin_unlock(&info->lock);
1118 copy_highpage(filepage, swappage);
1119 unlock_page(swappage);
1120 page_cache_release(swappage);
1121 flush_dcache_page(filepage);
1122 SetPageUptodate(filepage);
1123 set_page_dirty(filepage);
1124 swap_free(swap);
1125 } else if (!(error = move_from_swap_cache(
1126 swappage, idx, mapping))) {
1127 info->flags |= SHMEM_PAGEIN;
1128 shmem_swp_set(info, entry, 0);
1129 shmem_swp_unmap(entry);
1130 spin_unlock(&info->lock);
1131 filepage = swappage;
1132 swap_free(swap);
1133 } else {
1134 shmem_swp_unmap(entry);
1135 spin_unlock(&info->lock);
1136 unlock_page(swappage);
1137 page_cache_release(swappage);
1138 if (error == -ENOMEM) {
1139 /* let kswapd refresh zone for GFP_ATOMICs */
Andrew Morton3fcfab12006-10-19 23:28:16 -07001140 congestion_wait(WRITE, HZ/50);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 }
1142 goto repeat;
1143 }
1144 } else if (sgp == SGP_READ && !filepage) {
1145 shmem_swp_unmap(entry);
1146 filepage = find_get_page(mapping, idx);
1147 if (filepage &&
1148 (!PageUptodate(filepage) || TestSetPageLocked(filepage))) {
1149 spin_unlock(&info->lock);
1150 wait_on_page_locked(filepage);
1151 page_cache_release(filepage);
1152 filepage = NULL;
1153 goto repeat;
1154 }
1155 spin_unlock(&info->lock);
1156 } else {
1157 shmem_swp_unmap(entry);
1158 sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001159 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160 spin_lock(&sbinfo->stat_lock);
1161 if (sbinfo->free_blocks == 0 ||
1162 shmem_acct_block(info->flags)) {
1163 spin_unlock(&sbinfo->stat_lock);
1164 spin_unlock(&info->lock);
1165 error = -ENOSPC;
1166 goto failed;
1167 }
1168 sbinfo->free_blocks--;
1169 inode->i_blocks += BLOCKS_PER_PAGE;
1170 spin_unlock(&sbinfo->stat_lock);
1171 } else if (shmem_acct_block(info->flags)) {
1172 spin_unlock(&info->lock);
1173 error = -ENOSPC;
1174 goto failed;
1175 }
1176
1177 if (!filepage) {
1178 spin_unlock(&info->lock);
1179 filepage = shmem_alloc_page(mapping_gfp_mask(mapping),
1180 info,
1181 idx);
1182 if (!filepage) {
1183 shmem_unacct_blocks(info->flags, 1);
1184 shmem_free_blocks(inode, 1);
1185 error = -ENOMEM;
1186 goto failed;
1187 }
1188
1189 spin_lock(&info->lock);
1190 entry = shmem_swp_alloc(info, idx, sgp);
1191 if (IS_ERR(entry))
1192 error = PTR_ERR(entry);
1193 else {
1194 swap = *entry;
1195 shmem_swp_unmap(entry);
1196 }
1197 if (error || swap.val || 0 != add_to_page_cache_lru(
1198 filepage, mapping, idx, GFP_ATOMIC)) {
1199 spin_unlock(&info->lock);
1200 page_cache_release(filepage);
1201 shmem_unacct_blocks(info->flags, 1);
1202 shmem_free_blocks(inode, 1);
1203 filepage = NULL;
1204 if (error)
1205 goto failed;
1206 goto repeat;
1207 }
1208 info->flags |= SHMEM_PAGEIN;
1209 }
1210
1211 info->alloced++;
1212 spin_unlock(&info->lock);
1213 flush_dcache_page(filepage);
1214 SetPageUptodate(filepage);
1215 }
1216done:
1217 if (*pagep != filepage) {
1218 unlock_page(filepage);
1219 *pagep = filepage;
1220 }
1221 return 0;
1222
1223failed:
1224 if (*pagep != filepage) {
1225 unlock_page(filepage);
1226 page_cache_release(filepage);
1227 }
1228 return error;
1229}
1230
1231struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int *type)
1232{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001233 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234 struct page *page = NULL;
1235 unsigned long idx;
1236 int error;
1237
1238 idx = (address - vma->vm_start) >> PAGE_SHIFT;
1239 idx += vma->vm_pgoff;
1240 idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
1241 if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode))
1242 return NOPAGE_SIGBUS;
1243
1244 error = shmem_getpage(inode, idx, &page, SGP_CACHE, type);
1245 if (error)
1246 return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS;
1247
1248 mark_page_accessed(page);
1249 return page;
1250}
1251
1252static int shmem_populate(struct vm_area_struct *vma,
1253 unsigned long addr, unsigned long len,
1254 pgprot_t prot, unsigned long pgoff, int nonblock)
1255{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001256 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 struct mm_struct *mm = vma->vm_mm;
1258 enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE;
1259 unsigned long size;
1260
1261 size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
1262 if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size)
1263 return -EINVAL;
1264
1265 while ((long) len > 0) {
1266 struct page *page = NULL;
1267 int err;
1268 /*
1269 * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE
1270 */
1271 err = shmem_getpage(inode, pgoff, &page, sgp, NULL);
1272 if (err)
1273 return err;
Paolo 'Blaisorblade' Giarrussod44ed4f2005-09-03 15:54:55 -07001274 /* Page may still be null, but only if nonblock was set. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 if (page) {
1276 mark_page_accessed(page);
1277 err = install_page(mm, vma, addr, page, prot);
1278 if (err) {
1279 page_cache_release(page);
1280 return err;
1281 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001282 } else if (vma->vm_flags & VM_NONLINEAR) {
Paolo 'Blaisorblade' Giarrussod44ed4f2005-09-03 15:54:55 -07001283 /* No page was found just because we can't read it in
1284 * now (being here implies nonblock != 0), but the page
1285 * may exist, so set the PTE to fault it in later. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286 err = install_file_pte(mm, vma, addr, pgoff, prot);
1287 if (err)
1288 return err;
1289 }
1290
1291 len -= PAGE_SIZE;
1292 addr += PAGE_SIZE;
1293 pgoff++;
1294 }
1295 return 0;
1296}
1297
1298#ifdef CONFIG_NUMA
1299int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
1300{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001301 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
1303}
1304
1305struct mempolicy *
1306shmem_get_policy(struct vm_area_struct *vma, unsigned long addr)
1307{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001308 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309 unsigned long idx;
1310
1311 idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
1312 return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
1313}
1314#endif
1315
1316int shmem_lock(struct file *file, int lock, struct user_struct *user)
1317{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001318 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 struct shmem_inode_info *info = SHMEM_I(inode);
1320 int retval = -ENOMEM;
1321
1322 spin_lock(&info->lock);
1323 if (lock && !(info->flags & VM_LOCKED)) {
1324 if (!user_shm_lock(inode->i_size, user))
1325 goto out_nomem;
1326 info->flags |= VM_LOCKED;
1327 }
1328 if (!lock && (info->flags & VM_LOCKED) && user) {
1329 user_shm_unlock(inode->i_size, user);
1330 info->flags &= ~VM_LOCKED;
1331 }
1332 retval = 0;
1333out_nomem:
1334 spin_unlock(&info->lock);
1335 return retval;
1336}
1337
David Howellsb0e15192006-01-06 00:11:42 -08001338int shmem_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339{
1340 file_accessed(file);
1341 vma->vm_ops = &shmem_vm_ops;
1342 return 0;
1343}
1344
1345static struct inode *
1346shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
1347{
1348 struct inode *inode;
1349 struct shmem_inode_info *info;
1350 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
1351
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001352 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 spin_lock(&sbinfo->stat_lock);
1354 if (!sbinfo->free_inodes) {
1355 spin_unlock(&sbinfo->stat_lock);
1356 return NULL;
1357 }
1358 sbinfo->free_inodes--;
1359 spin_unlock(&sbinfo->stat_lock);
1360 }
1361
1362 inode = new_inode(sb);
1363 if (inode) {
1364 inode->i_mode = mode;
1365 inode->i_uid = current->fsuid;
1366 inode->i_gid = current->fsgid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367 inode->i_blocks = 0;
1368 inode->i_mapping->a_ops = &shmem_aops;
1369 inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
1370 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
David M. Grimes91828a42006-10-17 00:09:45 -07001371 inode->i_generation = get_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 info = SHMEM_I(inode);
1373 memset(info, 0, (char *)inode - (char *)info);
1374 spin_lock_init(&info->lock);
1375 INIT_LIST_HEAD(&info->swaplist);
1376
1377 switch (mode & S_IFMT) {
1378 default:
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001379 inode->i_op = &shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380 init_special_inode(inode, mode, dev);
1381 break;
1382 case S_IFREG:
1383 inode->i_op = &shmem_inode_operations;
1384 inode->i_fop = &shmem_file_operations;
Robin Holt7339ff82006-01-14 13:20:48 -08001385 mpol_shared_policy_init(&info->policy, sbinfo->policy,
1386 &sbinfo->policy_nodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 break;
1388 case S_IFDIR:
Dave Hansend8c76e62006-09-30 23:29:04 -07001389 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390 /* Some things misbehave if size == 0 on a directory */
1391 inode->i_size = 2 * BOGO_DIRENT_SIZE;
1392 inode->i_op = &shmem_dir_inode_operations;
1393 inode->i_fop = &simple_dir_operations;
1394 break;
1395 case S_IFLNK:
1396 /*
1397 * Must not load anything in the rbtree,
1398 * mpol_free_shared_policy will not be called.
1399 */
Robin Holt7339ff82006-01-14 13:20:48 -08001400 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT,
1401 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402 break;
1403 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001404 } else if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 spin_lock(&sbinfo->stat_lock);
1406 sbinfo->free_inodes++;
1407 spin_unlock(&sbinfo->stat_lock);
1408 }
1409 return inode;
1410}
1411
1412#ifdef CONFIG_TMPFS
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001413static const struct inode_operations shmem_symlink_inode_operations;
1414static const struct inode_operations shmem_symlink_inline_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
1416/*
1417 * Normally tmpfs makes no use of shmem_prepare_write, but it
1418 * lets a tmpfs file be used read-write below the loop driver.
1419 */
1420static int
1421shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
1422{
1423 struct inode *inode = page->mapping->host;
1424 return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL);
1425}
1426
1427static ssize_t
1428shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
1429{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001430 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 loff_t pos;
1432 unsigned long written;
1433 ssize_t err;
1434
1435 if ((ssize_t) count < 0)
1436 return -EINVAL;
1437
1438 if (!access_ok(VERIFY_READ, buf, count))
1439 return -EFAULT;
1440
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001441 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442
1443 pos = *ppos;
1444 written = 0;
1445
1446 err = generic_write_checks(file, &pos, &count, 0);
1447 if (err || !count)
1448 goto out;
1449
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001450 err = remove_suid(file->f_path.dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451 if (err)
1452 goto out;
1453
1454 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
1455
1456 do {
1457 struct page *page = NULL;
1458 unsigned long bytes, index, offset;
1459 char *kaddr;
1460 int left;
1461
1462 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
1463 index = pos >> PAGE_CACHE_SHIFT;
1464 bytes = PAGE_CACHE_SIZE - offset;
1465 if (bytes > count)
1466 bytes = count;
1467
1468 /*
1469 * We don't hold page lock across copy from user -
1470 * what would it guard against? - so no deadlock here.
1471 * But it still may be a good idea to prefault below.
1472 */
1473
1474 err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL);
1475 if (err)
1476 break;
1477
1478 left = bytes;
1479 if (PageHighMem(page)) {
1480 volatile unsigned char dummy;
1481 __get_user(dummy, buf);
1482 __get_user(dummy, buf + bytes - 1);
1483
1484 kaddr = kmap_atomic(page, KM_USER0);
1485 left = __copy_from_user_inatomic(kaddr + offset,
1486 buf, bytes);
1487 kunmap_atomic(kaddr, KM_USER0);
1488 }
1489 if (left) {
1490 kaddr = kmap(page);
1491 left = __copy_from_user(kaddr + offset, buf, bytes);
1492 kunmap(page);
1493 }
1494
1495 written += bytes;
1496 count -= bytes;
1497 pos += bytes;
1498 buf += bytes;
1499 if (pos > inode->i_size)
1500 i_size_write(inode, pos);
1501
1502 flush_dcache_page(page);
1503 set_page_dirty(page);
1504 mark_page_accessed(page);
1505 page_cache_release(page);
1506
1507 if (left) {
1508 pos -= left;
1509 written -= left;
1510 err = -EFAULT;
1511 break;
1512 }
1513
1514 /*
1515 * Our dirty pages are not counted in nr_dirty,
1516 * and we do not attempt to balance dirty pages.
1517 */
1518
1519 cond_resched();
1520 } while (count);
1521
1522 *ppos = pos;
1523 if (written)
1524 err = written;
1525out:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001526 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 return err;
1528}
1529
1530static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
1531{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001532 struct inode *inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 struct address_space *mapping = inode->i_mapping;
1534 unsigned long index, offset;
1535
1536 index = *ppos >> PAGE_CACHE_SHIFT;
1537 offset = *ppos & ~PAGE_CACHE_MASK;
1538
1539 for (;;) {
1540 struct page *page = NULL;
1541 unsigned long end_index, nr, ret;
1542 loff_t i_size = i_size_read(inode);
1543
1544 end_index = i_size >> PAGE_CACHE_SHIFT;
1545 if (index > end_index)
1546 break;
1547 if (index == end_index) {
1548 nr = i_size & ~PAGE_CACHE_MASK;
1549 if (nr <= offset)
1550 break;
1551 }
1552
1553 desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL);
1554 if (desc->error) {
1555 if (desc->error == -EINVAL)
1556 desc->error = 0;
1557 break;
1558 }
1559
1560 /*
1561 * We must evaluate after, since reads (unlike writes)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001562 * are called without i_mutex protection against truncate
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563 */
1564 nr = PAGE_CACHE_SIZE;
1565 i_size = i_size_read(inode);
1566 end_index = i_size >> PAGE_CACHE_SHIFT;
1567 if (index == end_index) {
1568 nr = i_size & ~PAGE_CACHE_MASK;
1569 if (nr <= offset) {
1570 if (page)
1571 page_cache_release(page);
1572 break;
1573 }
1574 }
1575 nr -= offset;
1576
1577 if (page) {
1578 /*
1579 * If users can be writing to this page using arbitrary
1580 * virtual addresses, take care about potential aliasing
1581 * before reading the page on the kernel side.
1582 */
1583 if (mapping_writably_mapped(mapping))
1584 flush_dcache_page(page);
1585 /*
1586 * Mark the page accessed if we read the beginning.
1587 */
1588 if (!offset)
1589 mark_page_accessed(page);
Nick Pigginb5810032005-10-29 18:16:12 -07001590 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001591 page = ZERO_PAGE(0);
Nick Pigginb5810032005-10-29 18:16:12 -07001592 page_cache_get(page);
1593 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594
1595 /*
1596 * Ok, we have the page, and it's up-to-date, so
1597 * now we can copy it to user space...
1598 *
1599 * The actor routine returns how many bytes were actually used..
1600 * NOTE! This may not be the same as how much of a user buffer
1601 * we filled up (we may be padding etc), so we can only update
1602 * "pos" here (the actor routine has to update the user buffer
1603 * pointers and the remaining count).
1604 */
1605 ret = actor(desc, page, offset, nr);
1606 offset += ret;
1607 index += offset >> PAGE_CACHE_SHIFT;
1608 offset &= ~PAGE_CACHE_MASK;
1609
1610 page_cache_release(page);
1611 if (ret != nr || !desc->count)
1612 break;
1613
1614 cond_resched();
1615 }
1616
1617 *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
1618 file_accessed(filp);
1619}
1620
1621static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
1622{
1623 read_descriptor_t desc;
1624
1625 if ((ssize_t) count < 0)
1626 return -EINVAL;
1627 if (!access_ok(VERIFY_WRITE, buf, count))
1628 return -EFAULT;
1629 if (!count)
1630 return 0;
1631
1632 desc.written = 0;
1633 desc.count = count;
1634 desc.arg.buf = buf;
1635 desc.error = 0;
1636
1637 do_shmem_file_read(filp, ppos, &desc, file_read_actor);
1638 if (desc.written)
1639 return desc.written;
1640 return desc.error;
1641}
1642
1643static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos,
1644 size_t count, read_actor_t actor, void *target)
1645{
1646 read_descriptor_t desc;
1647
1648 if (!count)
1649 return 0;
1650
1651 desc.written = 0;
1652 desc.count = count;
1653 desc.arg.data = target;
1654 desc.error = 0;
1655
1656 do_shmem_file_read(in_file, ppos, &desc, actor);
1657 if (desc.written)
1658 return desc.written;
1659 return desc.error;
1660}
1661
David Howells726c3342006-06-23 02:02:58 -07001662static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663{
David Howells726c3342006-06-23 02:02:58 -07001664 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665
1666 buf->f_type = TMPFS_MAGIC;
1667 buf->f_bsize = PAGE_CACHE_SIZE;
1668 buf->f_namelen = NAME_MAX;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001669 spin_lock(&sbinfo->stat_lock);
1670 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001671 buf->f_blocks = sbinfo->max_blocks;
1672 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001673 }
1674 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675 buf->f_files = sbinfo->max_inodes;
1676 buf->f_ffree = sbinfo->free_inodes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677 }
1678 /* else leave those fields 0 like simple_statfs */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001679 spin_unlock(&sbinfo->stat_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680 return 0;
1681}
1682
1683/*
1684 * File creation. Allocate an inode, and we're done..
1685 */
1686static int
1687shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1688{
1689 struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev);
1690 int error = -ENOSPC;
1691
1692 if (inode) {
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001693 error = security_inode_init_security(inode, dir, NULL, NULL,
1694 NULL);
1695 if (error) {
1696 if (error != -EOPNOTSUPP) {
1697 iput(inode);
1698 return error;
1699 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001700 }
1701 error = shmem_acl_init(inode, dir);
1702 if (error) {
1703 iput(inode);
1704 return error;
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001705 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706 if (dir->i_mode & S_ISGID) {
1707 inode->i_gid = dir->i_gid;
1708 if (S_ISDIR(mode))
1709 inode->i_mode |= S_ISGID;
1710 }
1711 dir->i_size += BOGO_DIRENT_SIZE;
1712 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1713 d_instantiate(dentry, inode);
1714 dget(dentry); /* Extra count - pin the dentry in core */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715 }
1716 return error;
1717}
1718
1719static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1720{
1721 int error;
1722
1723 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
1724 return error;
Dave Hansend8c76e62006-09-30 23:29:04 -07001725 inc_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 return 0;
1727}
1728
1729static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
1730 struct nameidata *nd)
1731{
1732 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
1733}
1734
1735/*
1736 * Link a file..
1737 */
1738static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1739{
1740 struct inode *inode = old_dentry->d_inode;
1741 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
1742
1743 /*
1744 * No ordinary (disk based) filesystem counts links as inodes;
1745 * but each new link needs a new dentry, pinning lowmem, and
1746 * tmpfs dentries cannot be pruned until they are unlinked.
1747 */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001748 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 spin_lock(&sbinfo->stat_lock);
1750 if (!sbinfo->free_inodes) {
1751 spin_unlock(&sbinfo->stat_lock);
1752 return -ENOSPC;
1753 }
1754 sbinfo->free_inodes--;
1755 spin_unlock(&sbinfo->stat_lock);
1756 }
1757
1758 dir->i_size += BOGO_DIRENT_SIZE;
1759 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -07001760 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 atomic_inc(&inode->i_count); /* New dentry reference */
1762 dget(dentry); /* Extra pinning count for the created dentry */
1763 d_instantiate(dentry, inode);
1764 return 0;
1765}
1766
1767static int shmem_unlink(struct inode *dir, struct dentry *dentry)
1768{
1769 struct inode *inode = dentry->d_inode;
1770
1771 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) {
1772 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001773 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774 spin_lock(&sbinfo->stat_lock);
1775 sbinfo->free_inodes++;
1776 spin_unlock(&sbinfo->stat_lock);
1777 }
1778 }
1779
1780 dir->i_size -= BOGO_DIRENT_SIZE;
1781 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001782 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 dput(dentry); /* Undo the count from "create" - this does all the work */
1784 return 0;
1785}
1786
1787static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
1788{
1789 if (!simple_empty(dentry))
1790 return -ENOTEMPTY;
1791
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001792 drop_nlink(dentry->d_inode);
1793 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 return shmem_unlink(dir, dentry);
1795}
1796
1797/*
1798 * The VFS layer already does all the dentry stuff for rename,
1799 * we just have to decrement the usage count for the target if
1800 * it exists so that the VFS layer correctly free's it when it
1801 * gets overwritten.
1802 */
1803static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
1804{
1805 struct inode *inode = old_dentry->d_inode;
1806 int they_are_dirs = S_ISDIR(inode->i_mode);
1807
1808 if (!simple_empty(new_dentry))
1809 return -ENOTEMPTY;
1810
1811 if (new_dentry->d_inode) {
1812 (void) shmem_unlink(new_dir, new_dentry);
1813 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001814 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001816 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -07001817 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001818 }
1819
1820 old_dir->i_size -= BOGO_DIRENT_SIZE;
1821 new_dir->i_size += BOGO_DIRENT_SIZE;
1822 old_dir->i_ctime = old_dir->i_mtime =
1823 new_dir->i_ctime = new_dir->i_mtime =
1824 inode->i_ctime = CURRENT_TIME;
1825 return 0;
1826}
1827
1828static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1829{
1830 int error;
1831 int len;
1832 struct inode *inode;
1833 struct page *page = NULL;
1834 char *kaddr;
1835 struct shmem_inode_info *info;
1836
1837 len = strlen(symname) + 1;
1838 if (len > PAGE_CACHE_SIZE)
1839 return -ENAMETOOLONG;
1840
1841 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
1842 if (!inode)
1843 return -ENOSPC;
1844
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001845 error = security_inode_init_security(inode, dir, NULL, NULL,
1846 NULL);
1847 if (error) {
1848 if (error != -EOPNOTSUPP) {
1849 iput(inode);
1850 return error;
1851 }
1852 error = 0;
1853 }
1854
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855 info = SHMEM_I(inode);
1856 inode->i_size = len-1;
1857 if (len <= (char *)inode - (char *)info) {
1858 /* do it inline */
1859 memcpy(info, symname, len);
1860 inode->i_op = &shmem_symlink_inline_operations;
1861 } else {
1862 error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
1863 if (error) {
1864 iput(inode);
1865 return error;
1866 }
1867 inode->i_op = &shmem_symlink_inode_operations;
1868 kaddr = kmap_atomic(page, KM_USER0);
1869 memcpy(kaddr, symname, len);
1870 kunmap_atomic(kaddr, KM_USER0);
1871 set_page_dirty(page);
1872 page_cache_release(page);
1873 }
1874 if (dir->i_mode & S_ISGID)
1875 inode->i_gid = dir->i_gid;
1876 dir->i_size += BOGO_DIRENT_SIZE;
1877 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1878 d_instantiate(dentry, inode);
1879 dget(dentry);
1880 return 0;
1881}
1882
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001883static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884{
1885 nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001886 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887}
1888
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001889static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890{
1891 struct page *page = NULL;
1892 int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
1893 nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001894 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895}
1896
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001897static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898{
1899 if (!IS_ERR(nd_get_link(nd))) {
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001900 struct page *page = cookie;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901 kunmap(page);
1902 mark_page_accessed(page);
1903 page_cache_release(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904 }
1905}
1906
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001907static const struct inode_operations shmem_symlink_inline_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 .readlink = generic_readlink,
1909 .follow_link = shmem_follow_link_inline,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910};
1911
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001912static const struct inode_operations shmem_symlink_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913 .truncate = shmem_truncate,
1914 .readlink = generic_readlink,
1915 .follow_link = shmem_follow_link,
1916 .put_link = shmem_put_link,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917};
1918
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001919#ifdef CONFIG_TMPFS_POSIX_ACL
1920/**
1921 * Superblocks without xattr inode operations will get security.* xattr
1922 * support from the VFS "for free". As soon as we have any other xattrs
1923 * like ACLs, we also need to implement the security.* handlers at
1924 * filesystem level, though.
1925 */
1926
1927static size_t shmem_xattr_security_list(struct inode *inode, char *list,
1928 size_t list_len, const char *name,
1929 size_t name_len)
1930{
1931 return security_inode_listsecurity(inode, list, list_len);
1932}
1933
1934static int shmem_xattr_security_get(struct inode *inode, const char *name,
1935 void *buffer, size_t size)
1936{
1937 if (strcmp(name, "") == 0)
1938 return -EINVAL;
1939 return security_inode_getsecurity(inode, name, buffer, size,
1940 -EOPNOTSUPP);
1941}
1942
1943static int shmem_xattr_security_set(struct inode *inode, const char *name,
1944 const void *value, size_t size, int flags)
1945{
1946 if (strcmp(name, "") == 0)
1947 return -EINVAL;
1948 return security_inode_setsecurity(inode, name, value, size, flags);
1949}
1950
Adrian Bunk1f370a22006-12-06 20:38:21 -08001951static struct xattr_handler shmem_xattr_security_handler = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001952 .prefix = XATTR_SECURITY_PREFIX,
1953 .list = shmem_xattr_security_list,
1954 .get = shmem_xattr_security_get,
1955 .set = shmem_xattr_security_set,
1956};
1957
1958static struct xattr_handler *shmem_xattr_handlers[] = {
1959 &shmem_xattr_acl_access_handler,
1960 &shmem_xattr_acl_default_handler,
1961 &shmem_xattr_security_handler,
1962 NULL
1963};
1964#endif
1965
David M. Grimes91828a42006-10-17 00:09:45 -07001966static struct dentry *shmem_get_parent(struct dentry *child)
1967{
1968 return ERR_PTR(-ESTALE);
1969}
1970
1971static int shmem_match(struct inode *ino, void *vfh)
1972{
1973 __u32 *fh = vfh;
1974 __u64 inum = fh[2];
1975 inum = (inum << 32) | fh[1];
1976 return ino->i_ino == inum && fh[0] == ino->i_generation;
1977}
1978
1979static struct dentry *shmem_get_dentry(struct super_block *sb, void *vfh)
1980{
1981 struct dentry *de = NULL;
1982 struct inode *inode;
1983 __u32 *fh = vfh;
1984 __u64 inum = fh[2];
1985 inum = (inum << 32) | fh[1];
1986
1987 inode = ilookup5(sb, (unsigned long)(inum+fh[0]), shmem_match, vfh);
1988 if (inode) {
1989 de = d_find_alias(inode);
1990 iput(inode);
1991 }
1992
1993 return de? de: ERR_PTR(-ESTALE);
1994}
1995
1996static struct dentry *shmem_decode_fh(struct super_block *sb, __u32 *fh,
1997 int len, int type,
1998 int (*acceptable)(void *context, struct dentry *de),
1999 void *context)
2000{
2001 if (len < 3)
2002 return ERR_PTR(-ESTALE);
2003
2004 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable,
2005 context);
2006}
2007
2008static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
2009 int connectable)
2010{
2011 struct inode *inode = dentry->d_inode;
2012
2013 if (*len < 3)
2014 return 255;
2015
2016 if (hlist_unhashed(&inode->i_hash)) {
2017 /* Unfortunately insert_inode_hash is not idempotent,
2018 * so as we hash inodes here rather than at creation
2019 * time, we need a lock to ensure we only try
2020 * to do it once
2021 */
2022 static DEFINE_SPINLOCK(lock);
2023 spin_lock(&lock);
2024 if (hlist_unhashed(&inode->i_hash))
2025 __insert_inode_hash(inode,
2026 inode->i_ino + inode->i_generation);
2027 spin_unlock(&lock);
2028 }
2029
2030 fh[0] = inode->i_generation;
2031 fh[1] = inode->i_ino;
2032 fh[2] = ((__u64)inode->i_ino) >> 32;
2033
2034 *len = 3;
2035 return 1;
2036}
2037
2038static struct export_operations shmem_export_ops = {
2039 .get_parent = shmem_get_parent,
2040 .get_dentry = shmem_get_dentry,
2041 .encode_fh = shmem_encode_fh,
2042 .decode_fh = shmem_decode_fh,
2043};
2044
Robin Holt7339ff82006-01-14 13:20:48 -08002045static int shmem_parse_options(char *options, int *mode, uid_t *uid,
2046 gid_t *gid, unsigned long *blocks, unsigned long *inodes,
2047 int *policy, nodemask_t *policy_nodes)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002048{
2049 char *this_char, *value, *rest;
2050
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002051 while (options != NULL) {
2052 this_char = options;
2053 for (;;) {
2054 /*
2055 * NUL-terminate this option: unfortunately,
2056 * mount options form a comma-separated list,
2057 * but mpol's nodelist may also contain commas.
2058 */
2059 options = strchr(options, ',');
2060 if (options == NULL)
2061 break;
2062 options++;
2063 if (!isdigit(*options)) {
2064 options[-1] = '\0';
2065 break;
2066 }
2067 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002068 if (!*this_char)
2069 continue;
2070 if ((value = strchr(this_char,'=')) != NULL) {
2071 *value++ = 0;
2072 } else {
2073 printk(KERN_ERR
2074 "tmpfs: No value for mount option '%s'\n",
2075 this_char);
2076 return 1;
2077 }
2078
2079 if (!strcmp(this_char,"size")) {
2080 unsigned long long size;
2081 size = memparse(value,&rest);
2082 if (*rest == '%') {
2083 size <<= PAGE_SHIFT;
2084 size *= totalram_pages;
2085 do_div(size, 100);
2086 rest++;
2087 }
2088 if (*rest)
2089 goto bad_val;
2090 *blocks = size >> PAGE_CACHE_SHIFT;
2091 } else if (!strcmp(this_char,"nr_blocks")) {
2092 *blocks = memparse(value,&rest);
2093 if (*rest)
2094 goto bad_val;
2095 } else if (!strcmp(this_char,"nr_inodes")) {
2096 *inodes = memparse(value,&rest);
2097 if (*rest)
2098 goto bad_val;
2099 } else if (!strcmp(this_char,"mode")) {
2100 if (!mode)
2101 continue;
2102 *mode = simple_strtoul(value,&rest,8);
2103 if (*rest)
2104 goto bad_val;
2105 } else if (!strcmp(this_char,"uid")) {
2106 if (!uid)
2107 continue;
2108 *uid = simple_strtoul(value,&rest,0);
2109 if (*rest)
2110 goto bad_val;
2111 } else if (!strcmp(this_char,"gid")) {
2112 if (!gid)
2113 continue;
2114 *gid = simple_strtoul(value,&rest,0);
2115 if (*rest)
2116 goto bad_val;
Robin Holt7339ff82006-01-14 13:20:48 -08002117 } else if (!strcmp(this_char,"mpol")) {
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002118 if (shmem_parse_mpol(value,policy,policy_nodes))
Robin Holt7339ff82006-01-14 13:20:48 -08002119 goto bad_val;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002120 } else {
2121 printk(KERN_ERR "tmpfs: Bad mount option %s\n",
2122 this_char);
2123 return 1;
2124 }
2125 }
2126 return 0;
2127
2128bad_val:
2129 printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
2130 value, this_char);
2131 return 1;
2132
2133}
2134
2135static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
2136{
2137 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002138 unsigned long max_blocks = sbinfo->max_blocks;
2139 unsigned long max_inodes = sbinfo->max_inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002140 int policy = sbinfo->policy;
2141 nodemask_t policy_nodes = sbinfo->policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002142 unsigned long blocks;
2143 unsigned long inodes;
2144 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002145
Robin Holt7339ff82006-01-14 13:20:48 -08002146 if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks,
2147 &max_inodes, &policy, &policy_nodes))
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002148 return error;
2149
2150 spin_lock(&sbinfo->stat_lock);
2151 blocks = sbinfo->max_blocks - sbinfo->free_blocks;
2152 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
2153 if (max_blocks < blocks)
2154 goto out;
2155 if (max_inodes < inodes)
2156 goto out;
2157 /*
2158 * Those tests also disallow limited->unlimited while any are in
2159 * use, so i_blocks will always be zero when max_blocks is zero;
2160 * but we must separately disallow unlimited->limited, because
2161 * in that case we have no record of how much is already in use.
2162 */
2163 if (max_blocks && !sbinfo->max_blocks)
2164 goto out;
2165 if (max_inodes && !sbinfo->max_inodes)
2166 goto out;
2167
2168 error = 0;
2169 sbinfo->max_blocks = max_blocks;
2170 sbinfo->free_blocks = max_blocks - blocks;
2171 sbinfo->max_inodes = max_inodes;
2172 sbinfo->free_inodes = max_inodes - inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002173 sbinfo->policy = policy;
2174 sbinfo->policy_nodes = policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002175out:
2176 spin_unlock(&sbinfo->stat_lock);
2177 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002178}
2179#endif
2180
2181static void shmem_put_super(struct super_block *sb)
2182{
2183 kfree(sb->s_fs_info);
2184 sb->s_fs_info = NULL;
2185}
2186
Linus Torvalds1da177e2005-04-16 15:20:36 -07002187static int shmem_fill_super(struct super_block *sb,
2188 void *data, int silent)
2189{
2190 struct inode *inode;
2191 struct dentry *root;
2192 int mode = S_IRWXUGO | S_ISVTX;
2193 uid_t uid = current->fsuid;
2194 gid_t gid = current->fsgid;
2195 int err = -ENOMEM;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002196 struct shmem_sb_info *sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002197 unsigned long blocks = 0;
2198 unsigned long inodes = 0;
Robin Holt7339ff82006-01-14 13:20:48 -08002199 int policy = MPOL_DEFAULT;
2200 nodemask_t policy_nodes = node_online_map;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002201
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002202#ifdef CONFIG_TMPFS
Linus Torvalds1da177e2005-04-16 15:20:36 -07002203 /*
2204 * Per default we only allow half of the physical ram per
2205 * tmpfs instance, limiting inodes to one per page of lowmem;
2206 * but the internal instance is left unlimited.
2207 */
2208 if (!(sb->s_flags & MS_NOUSER)) {
2209 blocks = totalram_pages / 2;
2210 inodes = totalram_pages - totalhigh_pages;
2211 if (inodes > blocks)
2212 inodes = blocks;
Robin Holt7339ff82006-01-14 13:20:48 -08002213 if (shmem_parse_options(data, &mode, &uid, &gid, &blocks,
2214 &inodes, &policy, &policy_nodes))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002215 return -EINVAL;
2216 }
David M. Grimes91828a42006-10-17 00:09:45 -07002217 sb->s_export_op = &shmem_export_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002218#else
2219 sb->s_flags |= MS_NOUSER;
2220#endif
2221
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002222 /* Round up to L1_CACHE_BYTES to resist false sharing */
2223 sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
2224 L1_CACHE_BYTES), GFP_KERNEL);
2225 if (!sbinfo)
2226 return -ENOMEM;
2227
2228 spin_lock_init(&sbinfo->stat_lock);
2229 sbinfo->max_blocks = blocks;
2230 sbinfo->free_blocks = blocks;
2231 sbinfo->max_inodes = inodes;
2232 sbinfo->free_inodes = inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002233 sbinfo->policy = policy;
2234 sbinfo->policy_nodes = policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002235
2236 sb->s_fs_info = sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002237 sb->s_maxbytes = SHMEM_MAX_BYTES;
2238 sb->s_blocksize = PAGE_CACHE_SIZE;
2239 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2240 sb->s_magic = TMPFS_MAGIC;
2241 sb->s_op = &shmem_ops;
Robin H. Johnsoncfd95a92006-06-12 21:50:25 +01002242 sb->s_time_gran = 1;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002243#ifdef CONFIG_TMPFS_POSIX_ACL
2244 sb->s_xattr = shmem_xattr_handlers;
2245 sb->s_flags |= MS_POSIXACL;
2246#endif
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002247
Linus Torvalds1da177e2005-04-16 15:20:36 -07002248 inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
2249 if (!inode)
2250 goto failed;
2251 inode->i_uid = uid;
2252 inode->i_gid = gid;
2253 root = d_alloc_root(inode);
2254 if (!root)
2255 goto failed_iput;
2256 sb->s_root = root;
2257 return 0;
2258
2259failed_iput:
2260 iput(inode);
2261failed:
2262 shmem_put_super(sb);
2263 return err;
2264}
2265
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002266static struct kmem_cache *shmem_inode_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267
2268static struct inode *shmem_alloc_inode(struct super_block *sb)
2269{
2270 struct shmem_inode_info *p;
Christoph Lametere94b1762006-12-06 20:33:17 -08002271 p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272 if (!p)
2273 return NULL;
2274 return &p->vfs_inode;
2275}
2276
2277static void shmem_destroy_inode(struct inode *inode)
2278{
2279 if ((inode->i_mode & S_IFMT) == S_IFREG) {
2280 /* only struct inode is valid if it's an inline symlink */
2281 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
2282 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002283 shmem_acl_destroy_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
2285}
2286
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002287static void init_once(void *foo, struct kmem_cache *cachep,
2288 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289{
2290 struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
2291
2292 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
2293 SLAB_CTOR_CONSTRUCTOR) {
2294 inode_init_once(&p->vfs_inode);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002295#ifdef CONFIG_TMPFS_POSIX_ACL
2296 p->i_acl = NULL;
2297 p->i_default_acl = NULL;
2298#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002299 }
2300}
2301
2302static int init_inodecache(void)
2303{
2304 shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
2305 sizeof(struct shmem_inode_info),
2306 0, 0, init_once, NULL);
2307 if (shmem_inode_cachep == NULL)
2308 return -ENOMEM;
2309 return 0;
2310}
2311
2312static void destroy_inodecache(void)
2313{
Alexey Dobriyan1a1d92c2006-09-27 01:49:40 -07002314 kmem_cache_destroy(shmem_inode_cachep);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002315}
2316
Christoph Hellwigf5e54d62006-06-28 04:26:44 -07002317static const struct address_space_operations shmem_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318 .writepage = shmem_writepage,
Ken Chen76719322007-02-10 01:43:15 -08002319 .set_page_dirty = __set_page_dirty_no_writeback,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320#ifdef CONFIG_TMPFS
2321 .prepare_write = shmem_prepare_write,
2322 .commit_write = simple_commit_write,
2323#endif
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -07002324 .migratepage = migrate_page,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002325};
2326
Helge Deller15ad7cd2006-12-06 20:40:36 -08002327static const struct file_operations shmem_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328 .mmap = shmem_mmap,
2329#ifdef CONFIG_TMPFS
2330 .llseek = generic_file_llseek,
2331 .read = shmem_file_read,
2332 .write = shmem_file_write,
2333 .fsync = simple_sync_file,
2334 .sendfile = shmem_file_sendfile,
2335#endif
2336};
2337
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002338static const struct inode_operations shmem_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002339 .truncate = shmem_truncate,
2340 .setattr = shmem_notify_change,
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002341 .truncate_range = shmem_truncate_range,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002342#ifdef CONFIG_TMPFS_POSIX_ACL
2343 .setxattr = generic_setxattr,
2344 .getxattr = generic_getxattr,
2345 .listxattr = generic_listxattr,
2346 .removexattr = generic_removexattr,
2347 .permission = shmem_permission,
2348#endif
2349
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350};
2351
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002352static const struct inode_operations shmem_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353#ifdef CONFIG_TMPFS
2354 .create = shmem_create,
2355 .lookup = simple_lookup,
2356 .link = shmem_link,
2357 .unlink = shmem_unlink,
2358 .symlink = shmem_symlink,
2359 .mkdir = shmem_mkdir,
2360 .rmdir = shmem_rmdir,
2361 .mknod = shmem_mknod,
2362 .rename = shmem_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002363#endif
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002364#ifdef CONFIG_TMPFS_POSIX_ACL
2365 .setattr = shmem_notify_change,
2366 .setxattr = generic_setxattr,
2367 .getxattr = generic_getxattr,
2368 .listxattr = generic_listxattr,
2369 .removexattr = generic_removexattr,
2370 .permission = shmem_permission,
2371#endif
2372};
2373
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002374static const struct inode_operations shmem_special_inode_operations = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002375#ifdef CONFIG_TMPFS_POSIX_ACL
2376 .setattr = shmem_notify_change,
2377 .setxattr = generic_setxattr,
2378 .getxattr = generic_getxattr,
2379 .listxattr = generic_listxattr,
2380 .removexattr = generic_removexattr,
2381 .permission = shmem_permission,
2382#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002383};
2384
2385static struct super_operations shmem_ops = {
2386 .alloc_inode = shmem_alloc_inode,
2387 .destroy_inode = shmem_destroy_inode,
2388#ifdef CONFIG_TMPFS
2389 .statfs = shmem_statfs,
2390 .remount_fs = shmem_remount_fs,
2391#endif
2392 .delete_inode = shmem_delete_inode,
2393 .drop_inode = generic_delete_inode,
2394 .put_super = shmem_put_super,
2395};
2396
2397static struct vm_operations_struct shmem_vm_ops = {
2398 .nopage = shmem_nopage,
2399 .populate = shmem_populate,
2400#ifdef CONFIG_NUMA
2401 .set_policy = shmem_set_policy,
2402 .get_policy = shmem_get_policy,
2403#endif
2404};
2405
2406
David Howells454e2392006-06-23 02:02:57 -07002407static int shmem_get_sb(struct file_system_type *fs_type,
2408 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002409{
David Howells454e2392006-06-23 02:02:57 -07002410 return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411}
2412
2413static struct file_system_type tmpfs_fs_type = {
2414 .owner = THIS_MODULE,
2415 .name = "tmpfs",
2416 .get_sb = shmem_get_sb,
2417 .kill_sb = kill_litter_super,
2418};
2419static struct vfsmount *shm_mnt;
2420
2421static int __init init_tmpfs(void)
2422{
2423 int error;
2424
2425 error = init_inodecache();
2426 if (error)
2427 goto out3;
2428
2429 error = register_filesystem(&tmpfs_fs_type);
2430 if (error) {
2431 printk(KERN_ERR "Could not register tmpfs\n");
2432 goto out2;
2433 }
Greg Kroah-Hartman95dc1122005-06-20 21:15:16 -07002434
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -04002435 shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002436 tmpfs_fs_type.name, NULL);
2437 if (IS_ERR(shm_mnt)) {
2438 error = PTR_ERR(shm_mnt);
2439 printk(KERN_ERR "Could not kern_mount tmpfs\n");
2440 goto out1;
2441 }
2442 return 0;
2443
2444out1:
2445 unregister_filesystem(&tmpfs_fs_type);
2446out2:
2447 destroy_inodecache();
2448out3:
2449 shm_mnt = ERR_PTR(error);
2450 return error;
2451}
2452module_init(init_tmpfs)
2453
2454/*
2455 * shmem_file_setup - get an unlinked file living in tmpfs
2456 *
2457 * @name: name for dentry (to be seen in /proc/<pid>/maps
2458 * @size: size to be set for the file
2459 *
2460 */
2461struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
2462{
2463 int error;
2464 struct file *file;
2465 struct inode *inode;
2466 struct dentry *dentry, *root;
2467 struct qstr this;
2468
2469 if (IS_ERR(shm_mnt))
2470 return (void *)shm_mnt;
2471
2472 if (size < 0 || size > SHMEM_MAX_BYTES)
2473 return ERR_PTR(-EINVAL);
2474
2475 if (shmem_acct_size(flags, size))
2476 return ERR_PTR(-ENOMEM);
2477
2478 error = -ENOMEM;
2479 this.name = name;
2480 this.len = strlen(name);
2481 this.hash = 0; /* will go */
2482 root = shm_mnt->mnt_root;
2483 dentry = d_alloc(root, &this);
2484 if (!dentry)
2485 goto put_memory;
2486
2487 error = -ENFILE;
2488 file = get_empty_filp();
2489 if (!file)
2490 goto put_dentry;
2491
2492 error = -ENOSPC;
2493 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
2494 if (!inode)
2495 goto close_file;
2496
2497 SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
2498 d_instantiate(dentry, inode);
2499 inode->i_size = size;
2500 inode->i_nlink = 0; /* It is unlinked */
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08002501 file->f_path.mnt = mntget(shm_mnt);
2502 file->f_path.dentry = dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002503 file->f_mapping = inode->i_mapping;
2504 file->f_op = &shmem_file_operations;
2505 file->f_mode = FMODE_WRITE | FMODE_READ;
2506 return file;
2507
2508close_file:
2509 put_filp(file);
2510put_dentry:
2511 dput(dentry);
2512put_memory:
2513 shmem_unacct_size(flags, size);
2514 return ERR_PTR(error);
2515}
2516
2517/*
2518 * shmem_zero_setup - setup a shared anonymous mapping
2519 *
2520 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2521 */
2522int shmem_zero_setup(struct vm_area_struct *vma)
2523{
2524 struct file *file;
2525 loff_t size = vma->vm_end - vma->vm_start;
2526
2527 file = shmem_file_setup("dev/zero", size, vma->vm_flags);
2528 if (IS_ERR(file))
2529 return PTR_ERR(file);
2530
2531 if (vma->vm_file)
2532 fput(vma->vm_file);
2533 vma->vm_file = file;
2534 vma->vm_ops = &shmem_vm_ops;
2535 return 0;
2536}