blob: 4959535fc14c4a7aa3308bb316c4a13a3ba2baa3 [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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180static struct file_operations shmem_file_operations;
181static struct inode_operations shmem_inode_operations;
182static struct inode_operations shmem_dir_inode_operations;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700183static 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 }
518 if (!topdir)
519 goto done2;
520
521 BUG_ON(limit <= SHMEM_NR_DIRECT);
522 limit -= SHMEM_NR_DIRECT;
523 idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
524 offset = idx % ENTRIES_PER_PAGE;
525 idx -= offset;
526
527 dir = shmem_dir_map(topdir);
528 stage = ENTRIES_PER_PAGEPAGE/2;
529 if (idx < ENTRIES_PER_PAGEPAGE/2) {
530 middir = topdir;
531 diroff = idx/ENTRIES_PER_PAGE;
532 } else {
533 dir += ENTRIES_PER_PAGE/2;
534 dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
535 while (stage <= idx)
536 stage += ENTRIES_PER_PAGEPAGE;
537 middir = *dir;
538 if (*dir) {
539 diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
540 ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
541 if (!diroff && !offset) {
542 *dir = NULL;
543 nr_pages_to_free++;
544 list_add(&middir->lru, &pages_to_free);
545 }
546 shmem_dir_unmap(dir);
547 dir = shmem_dir_map(middir);
548 } else {
549 diroff = 0;
550 offset = 0;
551 idx = stage;
552 }
553 }
554
555 for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
556 if (unlikely(idx == stage)) {
557 shmem_dir_unmap(dir);
558 dir = shmem_dir_map(topdir) +
559 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
560 while (!*dir) {
561 dir++;
562 idx += ENTRIES_PER_PAGEPAGE;
563 if (idx >= limit)
564 goto done1;
565 }
566 stage = idx + ENTRIES_PER_PAGEPAGE;
567 middir = *dir;
568 *dir = NULL;
569 nr_pages_to_free++;
570 list_add(&middir->lru, &pages_to_free);
571 shmem_dir_unmap(dir);
572 cond_resched();
573 dir = shmem_dir_map(middir);
574 diroff = 0;
575 }
576 subdir = dir[diroff];
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700577 if (subdir && page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 size = limit - idx;
579 if (size > ENTRIES_PER_PAGE)
580 size = ENTRIES_PER_PAGE;
581 freed = shmem_map_and_free_swp(subdir,
582 offset, size, &dir);
583 if (!dir)
584 dir = shmem_dir_map(middir);
585 nr_swaps_freed += freed;
586 if (offset)
587 spin_lock(&info->lock);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700588 set_page_private(subdir, page_private(subdir) - freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 if (offset)
590 spin_unlock(&info->lock);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800591 if (!punch_hole)
592 BUG_ON(page_private(subdir) > offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 }
594 if (offset)
595 offset = 0;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800596 else if (subdir && !page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 dir[diroff] = NULL;
598 nr_pages_to_free++;
599 list_add(&subdir->lru, &pages_to_free);
600 }
601 }
602done1:
603 shmem_dir_unmap(dir);
604done2:
605 if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
606 /*
607 * Call truncate_inode_pages again: racing shmem_unuse_inode
608 * may have swizzled a page in from swap since vmtruncate or
609 * generic_delete_inode did it, before we lowered next_index.
610 * Also, though shmem_getpage checks i_size before adding to
611 * cache, no recheck after: so fix the narrow window there too.
612 */
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800613 truncate_inode_pages_range(inode->i_mapping, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 }
615
616 spin_lock(&info->lock);
617 info->flags &= ~SHMEM_TRUNCATE;
618 info->swapped -= nr_swaps_freed;
619 if (nr_pages_to_free)
620 shmem_free_blocks(inode, nr_pages_to_free);
621 shmem_recalc_inode(inode);
622 spin_unlock(&info->lock);
623
624 /*
625 * Empty swap vector directory pages to be freed?
626 */
627 if (!list_empty(&pages_to_free)) {
628 pages_to_free.prev->next = NULL;
629 shmem_free_pages(pages_to_free.next);
630 }
631}
632
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800633static void shmem_truncate(struct inode *inode)
634{
635 shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
636}
637
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
639{
640 struct inode *inode = dentry->d_inode;
641 struct page *page = NULL;
642 int error;
643
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700644 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 if (attr->ia_size < inode->i_size) {
646 /*
647 * If truncating down to a partial page, then
648 * if that page is already allocated, hold it
649 * in memory until the truncation is over, so
650 * truncate_partial_page cannnot miss it were
651 * it assigned to swap.
652 */
653 if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
654 (void) shmem_getpage(inode,
655 attr->ia_size>>PAGE_CACHE_SHIFT,
656 &page, SGP_READ, NULL);
657 }
658 /*
659 * Reset SHMEM_PAGEIN flag so that shmem_truncate can
660 * detect if any pages might have been added to cache
661 * after truncate_inode_pages. But we needn't bother
662 * if it's being fully truncated to zero-length: the
663 * nrpages check is efficient enough in that case.
664 */
665 if (attr->ia_size) {
666 struct shmem_inode_info *info = SHMEM_I(inode);
667 spin_lock(&info->lock);
668 info->flags &= ~SHMEM_PAGEIN;
669 spin_unlock(&info->lock);
670 }
671 }
672 }
673
674 error = inode_change_ok(inode, attr);
675 if (!error)
676 error = inode_setattr(inode, attr);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700677#ifdef CONFIG_TMPFS_POSIX_ACL
678 if (!error && (attr->ia_valid & ATTR_MODE))
679 error = generic_acl_chmod(inode, &shmem_acl_ops);
680#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 if (page)
682 page_cache_release(page);
683 return error;
684}
685
686static void shmem_delete_inode(struct inode *inode)
687{
688 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
689 struct shmem_inode_info *info = SHMEM_I(inode);
690
691 if (inode->i_op->truncate == shmem_truncate) {
Mark Fashehfef26652005-09-09 13:01:31 -0700692 truncate_inode_pages(inode->i_mapping, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 shmem_unacct_size(info->flags, inode->i_size);
694 inode->i_size = 0;
695 shmem_truncate(inode);
696 if (!list_empty(&info->swaplist)) {
697 spin_lock(&shmem_swaplist_lock);
698 list_del_init(&info->swaplist);
699 spin_unlock(&shmem_swaplist_lock);
700 }
701 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700702 BUG_ON(inode->i_blocks);
703 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 spin_lock(&sbinfo->stat_lock);
705 sbinfo->free_inodes++;
706 spin_unlock(&sbinfo->stat_lock);
707 }
708 clear_inode(inode);
709}
710
711static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
712{
713 swp_entry_t *ptr;
714
715 for (ptr = dir; ptr < edir; ptr++) {
716 if (ptr->val == entry.val)
717 return ptr - dir;
718 }
719 return -1;
720}
721
722static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
723{
724 struct inode *inode;
725 unsigned long idx;
726 unsigned long size;
727 unsigned long limit;
728 unsigned long stage;
729 struct page **dir;
730 struct page *subdir;
731 swp_entry_t *ptr;
732 int offset;
733
734 idx = 0;
735 ptr = info->i_direct;
736 spin_lock(&info->lock);
737 limit = info->next_index;
738 size = limit;
739 if (size > SHMEM_NR_DIRECT)
740 size = SHMEM_NR_DIRECT;
741 offset = shmem_find_swp(entry, ptr, ptr+size);
742 if (offset >= 0) {
743 shmem_swp_balance_unmap();
744 goto found;
745 }
746 if (!info->i_indirect)
747 goto lost2;
748
749 dir = shmem_dir_map(info->i_indirect);
750 stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
751
752 for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
753 if (unlikely(idx == stage)) {
754 shmem_dir_unmap(dir-1);
755 dir = shmem_dir_map(info->i_indirect) +
756 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
757 while (!*dir) {
758 dir++;
759 idx += ENTRIES_PER_PAGEPAGE;
760 if (idx >= limit)
761 goto lost1;
762 }
763 stage = idx + ENTRIES_PER_PAGEPAGE;
764 subdir = *dir;
765 shmem_dir_unmap(dir);
766 dir = shmem_dir_map(subdir);
767 }
768 subdir = *dir;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700769 if (subdir && page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 ptr = shmem_swp_map(subdir);
771 size = limit - idx;
772 if (size > ENTRIES_PER_PAGE)
773 size = ENTRIES_PER_PAGE;
774 offset = shmem_find_swp(entry, ptr, ptr+size);
775 if (offset >= 0) {
776 shmem_dir_unmap(dir);
777 goto found;
778 }
779 shmem_swp_unmap(ptr);
780 }
781 }
782lost1:
783 shmem_dir_unmap(dir-1);
784lost2:
785 spin_unlock(&info->lock);
786 return 0;
787found:
788 idx += offset;
789 inode = &info->vfs_inode;
790 if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) {
791 info->flags |= SHMEM_PAGEIN;
792 shmem_swp_set(info, ptr + offset, 0);
793 }
794 shmem_swp_unmap(ptr);
795 spin_unlock(&info->lock);
796 /*
797 * Decrement swap count even when the entry is left behind:
798 * try_to_unuse will skip over mms, then reincrement count.
799 */
800 swap_free(entry);
801 return 1;
802}
803
804/*
805 * shmem_unuse() search for an eventually swapped out shmem page.
806 */
807int shmem_unuse(swp_entry_t entry, struct page *page)
808{
809 struct list_head *p, *next;
810 struct shmem_inode_info *info;
811 int found = 0;
812
813 spin_lock(&shmem_swaplist_lock);
814 list_for_each_safe(p, next, &shmem_swaplist) {
815 info = list_entry(p, struct shmem_inode_info, swaplist);
816 if (!info->swapped)
817 list_del_init(&info->swaplist);
818 else if (shmem_unuse_inode(info, entry, page)) {
819 /* move head to start search for next from here */
820 list_move_tail(&shmem_swaplist, &info->swaplist);
821 found = 1;
822 break;
823 }
824 }
825 spin_unlock(&shmem_swaplist_lock);
826 return found;
827}
828
829/*
830 * Move the page from the page cache to the swap cache.
831 */
832static int shmem_writepage(struct page *page, struct writeback_control *wbc)
833{
834 struct shmem_inode_info *info;
835 swp_entry_t *entry, swap;
836 struct address_space *mapping;
837 unsigned long index;
838 struct inode *inode;
839
840 BUG_ON(!PageLocked(page));
841 BUG_ON(page_mapped(page));
842
843 mapping = page->mapping;
844 index = page->index;
845 inode = mapping->host;
846 info = SHMEM_I(inode);
847 if (info->flags & VM_LOCKED)
848 goto redirty;
849 swap = get_swap_page();
850 if (!swap.val)
851 goto redirty;
852
853 spin_lock(&info->lock);
854 shmem_recalc_inode(inode);
855 if (index >= info->next_index) {
856 BUG_ON(!(info->flags & SHMEM_TRUNCATE));
857 goto unlock;
858 }
859 entry = shmem_swp_entry(info, index, NULL);
860 BUG_ON(!entry);
861 BUG_ON(entry->val);
862
863 if (move_to_swap_cache(page, swap) == 0) {
864 shmem_swp_set(info, entry, swap.val);
865 shmem_swp_unmap(entry);
866 spin_unlock(&info->lock);
867 if (list_empty(&info->swaplist)) {
868 spin_lock(&shmem_swaplist_lock);
869 /* move instead of add in case we're racing */
870 list_move_tail(&info->swaplist, &shmem_swaplist);
871 spin_unlock(&shmem_swaplist_lock);
872 }
873 unlock_page(page);
874 return 0;
875 }
876
877 shmem_swp_unmap(entry);
878unlock:
879 spin_unlock(&info->lock);
880 swap_free(swap);
881redirty:
882 set_page_dirty(page);
Zach Brown994fc28c2005-12-15 14:28:17 -0800883 return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884}
885
886#ifdef CONFIG_NUMA
Hugh Dickinsd15c0232006-03-22 00:08:46 -0800887static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +0000888{
889 char *nodelist = strchr(value, ':');
890 int err = 1;
891
892 if (nodelist) {
893 /* NUL-terminate policy string */
894 *nodelist++ = '\0';
895 if (nodelist_parse(nodelist, *policy_nodes))
896 goto out;
897 }
898 if (!strcmp(value, "default")) {
899 *policy = MPOL_DEFAULT;
900 /* Don't allow a nodelist */
901 if (!nodelist)
902 err = 0;
903 } else if (!strcmp(value, "prefer")) {
904 *policy = MPOL_PREFERRED;
905 /* Insist on a nodelist of one node only */
906 if (nodelist) {
907 char *rest = nodelist;
908 while (isdigit(*rest))
909 rest++;
910 if (!*rest)
911 err = 0;
912 }
913 } else if (!strcmp(value, "bind")) {
914 *policy = MPOL_BIND;
915 /* Insist on a nodelist */
916 if (nodelist)
917 err = 0;
918 } else if (!strcmp(value, "interleave")) {
919 *policy = MPOL_INTERLEAVE;
920 /* Default to nodes online if no nodelist */
921 if (!nodelist)
922 *policy_nodes = node_online_map;
923 err = 0;
924 }
925out:
926 /* Restore string for error message */
927 if (nodelist)
928 *--nodelist = ':';
929 return err;
930}
931
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932static struct page *shmem_swapin_async(struct shared_policy *p,
933 swp_entry_t entry, unsigned long idx)
934{
935 struct page *page;
936 struct vm_area_struct pvma;
937
938 /* Create a pseudo vma that just contains the policy */
939 memset(&pvma, 0, sizeof(struct vm_area_struct));
940 pvma.vm_end = PAGE_SIZE;
941 pvma.vm_pgoff = idx;
942 pvma.vm_policy = mpol_shared_policy_lookup(p, idx);
943 page = read_swap_cache_async(entry, &pvma, 0);
944 mpol_free(pvma.vm_policy);
945 return page;
946}
947
948struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry,
949 unsigned long idx)
950{
951 struct shared_policy *p = &info->policy;
952 int i, num;
953 struct page *page;
954 unsigned long offset;
955
956 num = valid_swaphandles(entry, &offset);
957 for (i = 0; i < num; offset++, i++) {
958 page = shmem_swapin_async(p,
959 swp_entry(swp_type(entry), offset), idx);
960 if (!page)
961 break;
962 page_cache_release(page);
963 }
964 lru_add_drain(); /* Push any new pages onto the LRU now */
965 return shmem_swapin_async(p, entry, idx);
966}
967
968static struct page *
Al Viro6daa0e22005-10-21 03:18:50 -0400969shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 unsigned long idx)
971{
972 struct vm_area_struct pvma;
973 struct page *page;
974
975 memset(&pvma, 0, sizeof(struct vm_area_struct));
976 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
977 pvma.vm_pgoff = idx;
978 pvma.vm_end = PAGE_SIZE;
979 page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0);
980 mpol_free(pvma.vm_policy);
981 return page;
982}
983#else
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +0000984static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
985{
986 return 1;
987}
988
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989static inline struct page *
990shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
991{
992 swapin_readahead(entry, 0, NULL);
993 return read_swap_cache_async(entry, NULL, 0);
994}
995
996static inline struct page *
Al Virodd0fc662005-10-07 07:46:04 +0100997shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998{
999 return alloc_page(gfp | __GFP_ZERO);
1000}
1001#endif
1002
1003/*
1004 * shmem_getpage - either get the page from swap or allocate a new one
1005 *
1006 * If we allocate a new one we do not mark it dirty. That's up to the
1007 * vm. If we swap it in we mark it dirty since we also free the swap
1008 * entry since a page cannot live in both the swap and page cache
1009 */
1010static int shmem_getpage(struct inode *inode, unsigned long idx,
1011 struct page **pagep, enum sgp_type sgp, int *type)
1012{
1013 struct address_space *mapping = inode->i_mapping;
1014 struct shmem_inode_info *info = SHMEM_I(inode);
1015 struct shmem_sb_info *sbinfo;
1016 struct page *filepage = *pagep;
1017 struct page *swappage;
1018 swp_entry_t *entry;
1019 swp_entry_t swap;
1020 int error;
1021
1022 if (idx >= SHMEM_MAX_INDEX)
1023 return -EFBIG;
1024 /*
1025 * Normally, filepage is NULL on entry, and either found
1026 * uptodate immediately, or allocated and zeroed, or read
1027 * in under swappage, which is then assigned to filepage.
1028 * But shmem_prepare_write passes in a locked filepage,
1029 * which may be found not uptodate by other callers too,
1030 * and may need to be copied from the swappage read in.
1031 */
1032repeat:
1033 if (!filepage)
1034 filepage = find_lock_page(mapping, idx);
1035 if (filepage && PageUptodate(filepage))
1036 goto done;
1037 error = 0;
1038 if (sgp == SGP_QUICK)
1039 goto failed;
1040
1041 spin_lock(&info->lock);
1042 shmem_recalc_inode(inode);
1043 entry = shmem_swp_alloc(info, idx, sgp);
1044 if (IS_ERR(entry)) {
1045 spin_unlock(&info->lock);
1046 error = PTR_ERR(entry);
1047 goto failed;
1048 }
1049 swap = *entry;
1050
1051 if (swap.val) {
1052 /* Look it up and read it in.. */
1053 swappage = lookup_swap_cache(swap);
1054 if (!swappage) {
1055 shmem_swp_unmap(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 /* here we actually do the io */
1057 if (type && *type == VM_FAULT_MINOR) {
Christoph Lameterf8891e52006-06-30 01:55:45 -07001058 __count_vm_event(PGMAJFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059 *type = VM_FAULT_MAJOR;
1060 }
Christoph Lameterf8891e52006-06-30 01:55:45 -07001061 spin_unlock(&info->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062 swappage = shmem_swapin(info, swap, idx);
1063 if (!swappage) {
1064 spin_lock(&info->lock);
1065 entry = shmem_swp_alloc(info, idx, sgp);
1066 if (IS_ERR(entry))
1067 error = PTR_ERR(entry);
1068 else {
1069 if (entry->val == swap.val)
1070 error = -ENOMEM;
1071 shmem_swp_unmap(entry);
1072 }
1073 spin_unlock(&info->lock);
1074 if (error)
1075 goto failed;
1076 goto repeat;
1077 }
1078 wait_on_page_locked(swappage);
1079 page_cache_release(swappage);
1080 goto repeat;
1081 }
1082
1083 /* We have to do this with page locked to prevent races */
1084 if (TestSetPageLocked(swappage)) {
1085 shmem_swp_unmap(entry);
1086 spin_unlock(&info->lock);
1087 wait_on_page_locked(swappage);
1088 page_cache_release(swappage);
1089 goto repeat;
1090 }
1091 if (PageWriteback(swappage)) {
1092 shmem_swp_unmap(entry);
1093 spin_unlock(&info->lock);
1094 wait_on_page_writeback(swappage);
1095 unlock_page(swappage);
1096 page_cache_release(swappage);
1097 goto repeat;
1098 }
1099 if (!PageUptodate(swappage)) {
1100 shmem_swp_unmap(entry);
1101 spin_unlock(&info->lock);
1102 unlock_page(swappage);
1103 page_cache_release(swappage);
1104 error = -EIO;
1105 goto failed;
1106 }
1107
1108 if (filepage) {
1109 shmem_swp_set(info, entry, 0);
1110 shmem_swp_unmap(entry);
1111 delete_from_swap_cache(swappage);
1112 spin_unlock(&info->lock);
1113 copy_highpage(filepage, swappage);
1114 unlock_page(swappage);
1115 page_cache_release(swappage);
1116 flush_dcache_page(filepage);
1117 SetPageUptodate(filepage);
1118 set_page_dirty(filepage);
1119 swap_free(swap);
1120 } else if (!(error = move_from_swap_cache(
1121 swappage, idx, mapping))) {
1122 info->flags |= SHMEM_PAGEIN;
1123 shmem_swp_set(info, entry, 0);
1124 shmem_swp_unmap(entry);
1125 spin_unlock(&info->lock);
1126 filepage = swappage;
1127 swap_free(swap);
1128 } else {
1129 shmem_swp_unmap(entry);
1130 spin_unlock(&info->lock);
1131 unlock_page(swappage);
1132 page_cache_release(swappage);
1133 if (error == -ENOMEM) {
1134 /* let kswapd refresh zone for GFP_ATOMICs */
Andrew Morton3fcfab12006-10-19 23:28:16 -07001135 congestion_wait(WRITE, HZ/50);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 }
1137 goto repeat;
1138 }
1139 } else if (sgp == SGP_READ && !filepage) {
1140 shmem_swp_unmap(entry);
1141 filepage = find_get_page(mapping, idx);
1142 if (filepage &&
1143 (!PageUptodate(filepage) || TestSetPageLocked(filepage))) {
1144 spin_unlock(&info->lock);
1145 wait_on_page_locked(filepage);
1146 page_cache_release(filepage);
1147 filepage = NULL;
1148 goto repeat;
1149 }
1150 spin_unlock(&info->lock);
1151 } else {
1152 shmem_swp_unmap(entry);
1153 sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001154 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 spin_lock(&sbinfo->stat_lock);
1156 if (sbinfo->free_blocks == 0 ||
1157 shmem_acct_block(info->flags)) {
1158 spin_unlock(&sbinfo->stat_lock);
1159 spin_unlock(&info->lock);
1160 error = -ENOSPC;
1161 goto failed;
1162 }
1163 sbinfo->free_blocks--;
1164 inode->i_blocks += BLOCKS_PER_PAGE;
1165 spin_unlock(&sbinfo->stat_lock);
1166 } else if (shmem_acct_block(info->flags)) {
1167 spin_unlock(&info->lock);
1168 error = -ENOSPC;
1169 goto failed;
1170 }
1171
1172 if (!filepage) {
1173 spin_unlock(&info->lock);
1174 filepage = shmem_alloc_page(mapping_gfp_mask(mapping),
1175 info,
1176 idx);
1177 if (!filepage) {
1178 shmem_unacct_blocks(info->flags, 1);
1179 shmem_free_blocks(inode, 1);
1180 error = -ENOMEM;
1181 goto failed;
1182 }
1183
1184 spin_lock(&info->lock);
1185 entry = shmem_swp_alloc(info, idx, sgp);
1186 if (IS_ERR(entry))
1187 error = PTR_ERR(entry);
1188 else {
1189 swap = *entry;
1190 shmem_swp_unmap(entry);
1191 }
1192 if (error || swap.val || 0 != add_to_page_cache_lru(
1193 filepage, mapping, idx, GFP_ATOMIC)) {
1194 spin_unlock(&info->lock);
1195 page_cache_release(filepage);
1196 shmem_unacct_blocks(info->flags, 1);
1197 shmem_free_blocks(inode, 1);
1198 filepage = NULL;
1199 if (error)
1200 goto failed;
1201 goto repeat;
1202 }
1203 info->flags |= SHMEM_PAGEIN;
1204 }
1205
1206 info->alloced++;
1207 spin_unlock(&info->lock);
1208 flush_dcache_page(filepage);
1209 SetPageUptodate(filepage);
1210 }
1211done:
1212 if (*pagep != filepage) {
1213 unlock_page(filepage);
1214 *pagep = filepage;
1215 }
1216 return 0;
1217
1218failed:
1219 if (*pagep != filepage) {
1220 unlock_page(filepage);
1221 page_cache_release(filepage);
1222 }
1223 return error;
1224}
1225
1226struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int *type)
1227{
1228 struct inode *inode = vma->vm_file->f_dentry->d_inode;
1229 struct page *page = NULL;
1230 unsigned long idx;
1231 int error;
1232
1233 idx = (address - vma->vm_start) >> PAGE_SHIFT;
1234 idx += vma->vm_pgoff;
1235 idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
1236 if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode))
1237 return NOPAGE_SIGBUS;
1238
1239 error = shmem_getpage(inode, idx, &page, SGP_CACHE, type);
1240 if (error)
1241 return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS;
1242
1243 mark_page_accessed(page);
1244 return page;
1245}
1246
1247static int shmem_populate(struct vm_area_struct *vma,
1248 unsigned long addr, unsigned long len,
1249 pgprot_t prot, unsigned long pgoff, int nonblock)
1250{
1251 struct inode *inode = vma->vm_file->f_dentry->d_inode;
1252 struct mm_struct *mm = vma->vm_mm;
1253 enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE;
1254 unsigned long size;
1255
1256 size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
1257 if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size)
1258 return -EINVAL;
1259
1260 while ((long) len > 0) {
1261 struct page *page = NULL;
1262 int err;
1263 /*
1264 * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE
1265 */
1266 err = shmem_getpage(inode, pgoff, &page, sgp, NULL);
1267 if (err)
1268 return err;
Paolo 'Blaisorblade' Giarrussod44ed4f2005-09-03 15:54:55 -07001269 /* Page may still be null, but only if nonblock was set. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 if (page) {
1271 mark_page_accessed(page);
1272 err = install_page(mm, vma, addr, page, prot);
1273 if (err) {
1274 page_cache_release(page);
1275 return err;
1276 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001277 } else if (vma->vm_flags & VM_NONLINEAR) {
Paolo 'Blaisorblade' Giarrussod44ed4f2005-09-03 15:54:55 -07001278 /* No page was found just because we can't read it in
1279 * now (being here implies nonblock != 0), but the page
1280 * may exist, so set the PTE to fault it in later. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 err = install_file_pte(mm, vma, addr, pgoff, prot);
1282 if (err)
1283 return err;
1284 }
1285
1286 len -= PAGE_SIZE;
1287 addr += PAGE_SIZE;
1288 pgoff++;
1289 }
1290 return 0;
1291}
1292
1293#ifdef CONFIG_NUMA
1294int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
1295{
1296 struct inode *i = vma->vm_file->f_dentry->d_inode;
1297 return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
1298}
1299
1300struct mempolicy *
1301shmem_get_policy(struct vm_area_struct *vma, unsigned long addr)
1302{
1303 struct inode *i = vma->vm_file->f_dentry->d_inode;
1304 unsigned long idx;
1305
1306 idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
1307 return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
1308}
1309#endif
1310
1311int shmem_lock(struct file *file, int lock, struct user_struct *user)
1312{
1313 struct inode *inode = file->f_dentry->d_inode;
1314 struct shmem_inode_info *info = SHMEM_I(inode);
1315 int retval = -ENOMEM;
1316
1317 spin_lock(&info->lock);
1318 if (lock && !(info->flags & VM_LOCKED)) {
1319 if (!user_shm_lock(inode->i_size, user))
1320 goto out_nomem;
1321 info->flags |= VM_LOCKED;
1322 }
1323 if (!lock && (info->flags & VM_LOCKED) && user) {
1324 user_shm_unlock(inode->i_size, user);
1325 info->flags &= ~VM_LOCKED;
1326 }
1327 retval = 0;
1328out_nomem:
1329 spin_unlock(&info->lock);
1330 return retval;
1331}
1332
David Howellsb0e15192006-01-06 00:11:42 -08001333int shmem_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334{
1335 file_accessed(file);
1336 vma->vm_ops = &shmem_vm_ops;
1337 return 0;
1338}
1339
1340static struct inode *
1341shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
1342{
1343 struct inode *inode;
1344 struct shmem_inode_info *info;
1345 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
1346
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001347 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 spin_lock(&sbinfo->stat_lock);
1349 if (!sbinfo->free_inodes) {
1350 spin_unlock(&sbinfo->stat_lock);
1351 return NULL;
1352 }
1353 sbinfo->free_inodes--;
1354 spin_unlock(&sbinfo->stat_lock);
1355 }
1356
1357 inode = new_inode(sb);
1358 if (inode) {
1359 inode->i_mode = mode;
1360 inode->i_uid = current->fsuid;
1361 inode->i_gid = current->fsgid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 inode->i_blocks = 0;
1363 inode->i_mapping->a_ops = &shmem_aops;
1364 inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
1365 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
David M. Grimes91828a42006-10-17 00:09:45 -07001366 inode->i_generation = get_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367 info = SHMEM_I(inode);
1368 memset(info, 0, (char *)inode - (char *)info);
1369 spin_lock_init(&info->lock);
1370 INIT_LIST_HEAD(&info->swaplist);
1371
1372 switch (mode & S_IFMT) {
1373 default:
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001374 inode->i_op = &shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375 init_special_inode(inode, mode, dev);
1376 break;
1377 case S_IFREG:
1378 inode->i_op = &shmem_inode_operations;
1379 inode->i_fop = &shmem_file_operations;
Robin Holt7339ff82006-01-14 13:20:48 -08001380 mpol_shared_policy_init(&info->policy, sbinfo->policy,
1381 &sbinfo->policy_nodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 break;
1383 case S_IFDIR:
Dave Hansend8c76e62006-09-30 23:29:04 -07001384 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385 /* Some things misbehave if size == 0 on a directory */
1386 inode->i_size = 2 * BOGO_DIRENT_SIZE;
1387 inode->i_op = &shmem_dir_inode_operations;
1388 inode->i_fop = &simple_dir_operations;
1389 break;
1390 case S_IFLNK:
1391 /*
1392 * Must not load anything in the rbtree,
1393 * mpol_free_shared_policy will not be called.
1394 */
Robin Holt7339ff82006-01-14 13:20:48 -08001395 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT,
1396 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 break;
1398 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001399 } else if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400 spin_lock(&sbinfo->stat_lock);
1401 sbinfo->free_inodes++;
1402 spin_unlock(&sbinfo->stat_lock);
1403 }
1404 return inode;
1405}
1406
1407#ifdef CONFIG_TMPFS
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408static struct inode_operations shmem_symlink_inode_operations;
1409static struct inode_operations shmem_symlink_inline_operations;
1410
1411/*
1412 * Normally tmpfs makes no use of shmem_prepare_write, but it
1413 * lets a tmpfs file be used read-write below the loop driver.
1414 */
1415static int
1416shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
1417{
1418 struct inode *inode = page->mapping->host;
1419 return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL);
1420}
1421
1422static ssize_t
1423shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
1424{
1425 struct inode *inode = file->f_dentry->d_inode;
1426 loff_t pos;
1427 unsigned long written;
1428 ssize_t err;
1429
1430 if ((ssize_t) count < 0)
1431 return -EINVAL;
1432
1433 if (!access_ok(VERIFY_READ, buf, count))
1434 return -EFAULT;
1435
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001436 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437
1438 pos = *ppos;
1439 written = 0;
1440
1441 err = generic_write_checks(file, &pos, &count, 0);
1442 if (err || !count)
1443 goto out;
1444
1445 err = remove_suid(file->f_dentry);
1446 if (err)
1447 goto out;
1448
1449 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
1450
1451 do {
1452 struct page *page = NULL;
1453 unsigned long bytes, index, offset;
1454 char *kaddr;
1455 int left;
1456
1457 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
1458 index = pos >> PAGE_CACHE_SHIFT;
1459 bytes = PAGE_CACHE_SIZE - offset;
1460 if (bytes > count)
1461 bytes = count;
1462
1463 /*
1464 * We don't hold page lock across copy from user -
1465 * what would it guard against? - so no deadlock here.
1466 * But it still may be a good idea to prefault below.
1467 */
1468
1469 err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL);
1470 if (err)
1471 break;
1472
1473 left = bytes;
1474 if (PageHighMem(page)) {
1475 volatile unsigned char dummy;
1476 __get_user(dummy, buf);
1477 __get_user(dummy, buf + bytes - 1);
1478
1479 kaddr = kmap_atomic(page, KM_USER0);
1480 left = __copy_from_user_inatomic(kaddr + offset,
1481 buf, bytes);
1482 kunmap_atomic(kaddr, KM_USER0);
1483 }
1484 if (left) {
1485 kaddr = kmap(page);
1486 left = __copy_from_user(kaddr + offset, buf, bytes);
1487 kunmap(page);
1488 }
1489
1490 written += bytes;
1491 count -= bytes;
1492 pos += bytes;
1493 buf += bytes;
1494 if (pos > inode->i_size)
1495 i_size_write(inode, pos);
1496
1497 flush_dcache_page(page);
1498 set_page_dirty(page);
1499 mark_page_accessed(page);
1500 page_cache_release(page);
1501
1502 if (left) {
1503 pos -= left;
1504 written -= left;
1505 err = -EFAULT;
1506 break;
1507 }
1508
1509 /*
1510 * Our dirty pages are not counted in nr_dirty,
1511 * and we do not attempt to balance dirty pages.
1512 */
1513
1514 cond_resched();
1515 } while (count);
1516
1517 *ppos = pos;
1518 if (written)
1519 err = written;
1520out:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001521 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001522 return err;
1523}
1524
1525static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
1526{
1527 struct inode *inode = filp->f_dentry->d_inode;
1528 struct address_space *mapping = inode->i_mapping;
1529 unsigned long index, offset;
1530
1531 index = *ppos >> PAGE_CACHE_SHIFT;
1532 offset = *ppos & ~PAGE_CACHE_MASK;
1533
1534 for (;;) {
1535 struct page *page = NULL;
1536 unsigned long end_index, nr, ret;
1537 loff_t i_size = i_size_read(inode);
1538
1539 end_index = i_size >> PAGE_CACHE_SHIFT;
1540 if (index > end_index)
1541 break;
1542 if (index == end_index) {
1543 nr = i_size & ~PAGE_CACHE_MASK;
1544 if (nr <= offset)
1545 break;
1546 }
1547
1548 desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL);
1549 if (desc->error) {
1550 if (desc->error == -EINVAL)
1551 desc->error = 0;
1552 break;
1553 }
1554
1555 /*
1556 * We must evaluate after, since reads (unlike writes)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001557 * are called without i_mutex protection against truncate
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558 */
1559 nr = PAGE_CACHE_SIZE;
1560 i_size = i_size_read(inode);
1561 end_index = i_size >> PAGE_CACHE_SHIFT;
1562 if (index == end_index) {
1563 nr = i_size & ~PAGE_CACHE_MASK;
1564 if (nr <= offset) {
1565 if (page)
1566 page_cache_release(page);
1567 break;
1568 }
1569 }
1570 nr -= offset;
1571
1572 if (page) {
1573 /*
1574 * If users can be writing to this page using arbitrary
1575 * virtual addresses, take care about potential aliasing
1576 * before reading the page on the kernel side.
1577 */
1578 if (mapping_writably_mapped(mapping))
1579 flush_dcache_page(page);
1580 /*
1581 * Mark the page accessed if we read the beginning.
1582 */
1583 if (!offset)
1584 mark_page_accessed(page);
Nick Pigginb5810032005-10-29 18:16:12 -07001585 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586 page = ZERO_PAGE(0);
Nick Pigginb5810032005-10-29 18:16:12 -07001587 page_cache_get(page);
1588 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589
1590 /*
1591 * Ok, we have the page, and it's up-to-date, so
1592 * now we can copy it to user space...
1593 *
1594 * The actor routine returns how many bytes were actually used..
1595 * NOTE! This may not be the same as how much of a user buffer
1596 * we filled up (we may be padding etc), so we can only update
1597 * "pos" here (the actor routine has to update the user buffer
1598 * pointers and the remaining count).
1599 */
1600 ret = actor(desc, page, offset, nr);
1601 offset += ret;
1602 index += offset >> PAGE_CACHE_SHIFT;
1603 offset &= ~PAGE_CACHE_MASK;
1604
1605 page_cache_release(page);
1606 if (ret != nr || !desc->count)
1607 break;
1608
1609 cond_resched();
1610 }
1611
1612 *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
1613 file_accessed(filp);
1614}
1615
1616static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
1617{
1618 read_descriptor_t desc;
1619
1620 if ((ssize_t) count < 0)
1621 return -EINVAL;
1622 if (!access_ok(VERIFY_WRITE, buf, count))
1623 return -EFAULT;
1624 if (!count)
1625 return 0;
1626
1627 desc.written = 0;
1628 desc.count = count;
1629 desc.arg.buf = buf;
1630 desc.error = 0;
1631
1632 do_shmem_file_read(filp, ppos, &desc, file_read_actor);
1633 if (desc.written)
1634 return desc.written;
1635 return desc.error;
1636}
1637
1638static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos,
1639 size_t count, read_actor_t actor, void *target)
1640{
1641 read_descriptor_t desc;
1642
1643 if (!count)
1644 return 0;
1645
1646 desc.written = 0;
1647 desc.count = count;
1648 desc.arg.data = target;
1649 desc.error = 0;
1650
1651 do_shmem_file_read(in_file, ppos, &desc, actor);
1652 if (desc.written)
1653 return desc.written;
1654 return desc.error;
1655}
1656
David Howells726c3342006-06-23 02:02:58 -07001657static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658{
David Howells726c3342006-06-23 02:02:58 -07001659 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660
1661 buf->f_type = TMPFS_MAGIC;
1662 buf->f_bsize = PAGE_CACHE_SIZE;
1663 buf->f_namelen = NAME_MAX;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001664 spin_lock(&sbinfo->stat_lock);
1665 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 buf->f_blocks = sbinfo->max_blocks;
1667 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001668 }
1669 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 buf->f_files = sbinfo->max_inodes;
1671 buf->f_ffree = sbinfo->free_inodes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672 }
1673 /* else leave those fields 0 like simple_statfs */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001674 spin_unlock(&sbinfo->stat_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675 return 0;
1676}
1677
1678/*
1679 * File creation. Allocate an inode, and we're done..
1680 */
1681static int
1682shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1683{
1684 struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev);
1685 int error = -ENOSPC;
1686
1687 if (inode) {
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001688 error = security_inode_init_security(inode, dir, NULL, NULL,
1689 NULL);
1690 if (error) {
1691 if (error != -EOPNOTSUPP) {
1692 iput(inode);
1693 return error;
1694 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001695 }
1696 error = shmem_acl_init(inode, dir);
1697 if (error) {
1698 iput(inode);
1699 return error;
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001700 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 if (dir->i_mode & S_ISGID) {
1702 inode->i_gid = dir->i_gid;
1703 if (S_ISDIR(mode))
1704 inode->i_mode |= S_ISGID;
1705 }
1706 dir->i_size += BOGO_DIRENT_SIZE;
1707 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1708 d_instantiate(dentry, inode);
1709 dget(dentry); /* Extra count - pin the dentry in core */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 }
1711 return error;
1712}
1713
1714static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1715{
1716 int error;
1717
1718 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
1719 return error;
Dave Hansend8c76e62006-09-30 23:29:04 -07001720 inc_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721 return 0;
1722}
1723
1724static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
1725 struct nameidata *nd)
1726{
1727 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
1728}
1729
1730/*
1731 * Link a file..
1732 */
1733static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1734{
1735 struct inode *inode = old_dentry->d_inode;
1736 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
1737
1738 /*
1739 * No ordinary (disk based) filesystem counts links as inodes;
1740 * but each new link needs a new dentry, pinning lowmem, and
1741 * tmpfs dentries cannot be pruned until they are unlinked.
1742 */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001743 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001744 spin_lock(&sbinfo->stat_lock);
1745 if (!sbinfo->free_inodes) {
1746 spin_unlock(&sbinfo->stat_lock);
1747 return -ENOSPC;
1748 }
1749 sbinfo->free_inodes--;
1750 spin_unlock(&sbinfo->stat_lock);
1751 }
1752
1753 dir->i_size += BOGO_DIRENT_SIZE;
1754 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -07001755 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756 atomic_inc(&inode->i_count); /* New dentry reference */
1757 dget(dentry); /* Extra pinning count for the created dentry */
1758 d_instantiate(dentry, inode);
1759 return 0;
1760}
1761
1762static int shmem_unlink(struct inode *dir, struct dentry *dentry)
1763{
1764 struct inode *inode = dentry->d_inode;
1765
1766 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) {
1767 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001768 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 spin_lock(&sbinfo->stat_lock);
1770 sbinfo->free_inodes++;
1771 spin_unlock(&sbinfo->stat_lock);
1772 }
1773 }
1774
1775 dir->i_size -= BOGO_DIRENT_SIZE;
1776 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001777 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 dput(dentry); /* Undo the count from "create" - this does all the work */
1779 return 0;
1780}
1781
1782static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
1783{
1784 if (!simple_empty(dentry))
1785 return -ENOTEMPTY;
1786
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001787 drop_nlink(dentry->d_inode);
1788 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 return shmem_unlink(dir, dentry);
1790}
1791
1792/*
1793 * The VFS layer already does all the dentry stuff for rename,
1794 * we just have to decrement the usage count for the target if
1795 * it exists so that the VFS layer correctly free's it when it
1796 * gets overwritten.
1797 */
1798static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
1799{
1800 struct inode *inode = old_dentry->d_inode;
1801 int they_are_dirs = S_ISDIR(inode->i_mode);
1802
1803 if (!simple_empty(new_dentry))
1804 return -ENOTEMPTY;
1805
1806 if (new_dentry->d_inode) {
1807 (void) shmem_unlink(new_dir, new_dentry);
1808 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001809 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001811 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -07001812 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813 }
1814
1815 old_dir->i_size -= BOGO_DIRENT_SIZE;
1816 new_dir->i_size += BOGO_DIRENT_SIZE;
1817 old_dir->i_ctime = old_dir->i_mtime =
1818 new_dir->i_ctime = new_dir->i_mtime =
1819 inode->i_ctime = CURRENT_TIME;
1820 return 0;
1821}
1822
1823static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1824{
1825 int error;
1826 int len;
1827 struct inode *inode;
1828 struct page *page = NULL;
1829 char *kaddr;
1830 struct shmem_inode_info *info;
1831
1832 len = strlen(symname) + 1;
1833 if (len > PAGE_CACHE_SIZE)
1834 return -ENAMETOOLONG;
1835
1836 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
1837 if (!inode)
1838 return -ENOSPC;
1839
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001840 error = security_inode_init_security(inode, dir, NULL, NULL,
1841 NULL);
1842 if (error) {
1843 if (error != -EOPNOTSUPP) {
1844 iput(inode);
1845 return error;
1846 }
1847 error = 0;
1848 }
1849
Linus Torvalds1da177e2005-04-16 15:20:36 -07001850 info = SHMEM_I(inode);
1851 inode->i_size = len-1;
1852 if (len <= (char *)inode - (char *)info) {
1853 /* do it inline */
1854 memcpy(info, symname, len);
1855 inode->i_op = &shmem_symlink_inline_operations;
1856 } else {
1857 error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
1858 if (error) {
1859 iput(inode);
1860 return error;
1861 }
1862 inode->i_op = &shmem_symlink_inode_operations;
1863 kaddr = kmap_atomic(page, KM_USER0);
1864 memcpy(kaddr, symname, len);
1865 kunmap_atomic(kaddr, KM_USER0);
1866 set_page_dirty(page);
1867 page_cache_release(page);
1868 }
1869 if (dir->i_mode & S_ISGID)
1870 inode->i_gid = dir->i_gid;
1871 dir->i_size += BOGO_DIRENT_SIZE;
1872 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1873 d_instantiate(dentry, inode);
1874 dget(dentry);
1875 return 0;
1876}
1877
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001878static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879{
1880 nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001881 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882}
1883
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001884static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885{
1886 struct page *page = NULL;
1887 int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
1888 nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001889 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890}
1891
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001892static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893{
1894 if (!IS_ERR(nd_get_link(nd))) {
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001895 struct page *page = cookie;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 kunmap(page);
1897 mark_page_accessed(page);
1898 page_cache_release(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001899 }
1900}
1901
1902static struct inode_operations shmem_symlink_inline_operations = {
1903 .readlink = generic_readlink,
1904 .follow_link = shmem_follow_link_inline,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001905};
1906
1907static struct inode_operations shmem_symlink_inode_operations = {
1908 .truncate = shmem_truncate,
1909 .readlink = generic_readlink,
1910 .follow_link = shmem_follow_link,
1911 .put_link = shmem_put_link,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001912};
1913
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001914#ifdef CONFIG_TMPFS_POSIX_ACL
1915/**
1916 * Superblocks without xattr inode operations will get security.* xattr
1917 * support from the VFS "for free". As soon as we have any other xattrs
1918 * like ACLs, we also need to implement the security.* handlers at
1919 * filesystem level, though.
1920 */
1921
1922static size_t shmem_xattr_security_list(struct inode *inode, char *list,
1923 size_t list_len, const char *name,
1924 size_t name_len)
1925{
1926 return security_inode_listsecurity(inode, list, list_len);
1927}
1928
1929static int shmem_xattr_security_get(struct inode *inode, const char *name,
1930 void *buffer, size_t size)
1931{
1932 if (strcmp(name, "") == 0)
1933 return -EINVAL;
1934 return security_inode_getsecurity(inode, name, buffer, size,
1935 -EOPNOTSUPP);
1936}
1937
1938static int shmem_xattr_security_set(struct inode *inode, const char *name,
1939 const void *value, size_t size, int flags)
1940{
1941 if (strcmp(name, "") == 0)
1942 return -EINVAL;
1943 return security_inode_setsecurity(inode, name, value, size, flags);
1944}
1945
1946struct xattr_handler shmem_xattr_security_handler = {
1947 .prefix = XATTR_SECURITY_PREFIX,
1948 .list = shmem_xattr_security_list,
1949 .get = shmem_xattr_security_get,
1950 .set = shmem_xattr_security_set,
1951};
1952
1953static struct xattr_handler *shmem_xattr_handlers[] = {
1954 &shmem_xattr_acl_access_handler,
1955 &shmem_xattr_acl_default_handler,
1956 &shmem_xattr_security_handler,
1957 NULL
1958};
1959#endif
1960
David M. Grimes91828a42006-10-17 00:09:45 -07001961static struct dentry *shmem_get_parent(struct dentry *child)
1962{
1963 return ERR_PTR(-ESTALE);
1964}
1965
1966static int shmem_match(struct inode *ino, void *vfh)
1967{
1968 __u32 *fh = vfh;
1969 __u64 inum = fh[2];
1970 inum = (inum << 32) | fh[1];
1971 return ino->i_ino == inum && fh[0] == ino->i_generation;
1972}
1973
1974static struct dentry *shmem_get_dentry(struct super_block *sb, void *vfh)
1975{
1976 struct dentry *de = NULL;
1977 struct inode *inode;
1978 __u32 *fh = vfh;
1979 __u64 inum = fh[2];
1980 inum = (inum << 32) | fh[1];
1981
1982 inode = ilookup5(sb, (unsigned long)(inum+fh[0]), shmem_match, vfh);
1983 if (inode) {
1984 de = d_find_alias(inode);
1985 iput(inode);
1986 }
1987
1988 return de? de: ERR_PTR(-ESTALE);
1989}
1990
1991static struct dentry *shmem_decode_fh(struct super_block *sb, __u32 *fh,
1992 int len, int type,
1993 int (*acceptable)(void *context, struct dentry *de),
1994 void *context)
1995{
1996 if (len < 3)
1997 return ERR_PTR(-ESTALE);
1998
1999 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable,
2000 context);
2001}
2002
2003static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
2004 int connectable)
2005{
2006 struct inode *inode = dentry->d_inode;
2007
2008 if (*len < 3)
2009 return 255;
2010
2011 if (hlist_unhashed(&inode->i_hash)) {
2012 /* Unfortunately insert_inode_hash is not idempotent,
2013 * so as we hash inodes here rather than at creation
2014 * time, we need a lock to ensure we only try
2015 * to do it once
2016 */
2017 static DEFINE_SPINLOCK(lock);
2018 spin_lock(&lock);
2019 if (hlist_unhashed(&inode->i_hash))
2020 __insert_inode_hash(inode,
2021 inode->i_ino + inode->i_generation);
2022 spin_unlock(&lock);
2023 }
2024
2025 fh[0] = inode->i_generation;
2026 fh[1] = inode->i_ino;
2027 fh[2] = ((__u64)inode->i_ino) >> 32;
2028
2029 *len = 3;
2030 return 1;
2031}
2032
2033static struct export_operations shmem_export_ops = {
2034 .get_parent = shmem_get_parent,
2035 .get_dentry = shmem_get_dentry,
2036 .encode_fh = shmem_encode_fh,
2037 .decode_fh = shmem_decode_fh,
2038};
2039
Robin Holt7339ff82006-01-14 13:20:48 -08002040static int shmem_parse_options(char *options, int *mode, uid_t *uid,
2041 gid_t *gid, unsigned long *blocks, unsigned long *inodes,
2042 int *policy, nodemask_t *policy_nodes)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043{
2044 char *this_char, *value, *rest;
2045
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002046 while (options != NULL) {
2047 this_char = options;
2048 for (;;) {
2049 /*
2050 * NUL-terminate this option: unfortunately,
2051 * mount options form a comma-separated list,
2052 * but mpol's nodelist may also contain commas.
2053 */
2054 options = strchr(options, ',');
2055 if (options == NULL)
2056 break;
2057 options++;
2058 if (!isdigit(*options)) {
2059 options[-1] = '\0';
2060 break;
2061 }
2062 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002063 if (!*this_char)
2064 continue;
2065 if ((value = strchr(this_char,'=')) != NULL) {
2066 *value++ = 0;
2067 } else {
2068 printk(KERN_ERR
2069 "tmpfs: No value for mount option '%s'\n",
2070 this_char);
2071 return 1;
2072 }
2073
2074 if (!strcmp(this_char,"size")) {
2075 unsigned long long size;
2076 size = memparse(value,&rest);
2077 if (*rest == '%') {
2078 size <<= PAGE_SHIFT;
2079 size *= totalram_pages;
2080 do_div(size, 100);
2081 rest++;
2082 }
2083 if (*rest)
2084 goto bad_val;
2085 *blocks = size >> PAGE_CACHE_SHIFT;
2086 } else if (!strcmp(this_char,"nr_blocks")) {
2087 *blocks = memparse(value,&rest);
2088 if (*rest)
2089 goto bad_val;
2090 } else if (!strcmp(this_char,"nr_inodes")) {
2091 *inodes = memparse(value,&rest);
2092 if (*rest)
2093 goto bad_val;
2094 } else if (!strcmp(this_char,"mode")) {
2095 if (!mode)
2096 continue;
2097 *mode = simple_strtoul(value,&rest,8);
2098 if (*rest)
2099 goto bad_val;
2100 } else if (!strcmp(this_char,"uid")) {
2101 if (!uid)
2102 continue;
2103 *uid = simple_strtoul(value,&rest,0);
2104 if (*rest)
2105 goto bad_val;
2106 } else if (!strcmp(this_char,"gid")) {
2107 if (!gid)
2108 continue;
2109 *gid = simple_strtoul(value,&rest,0);
2110 if (*rest)
2111 goto bad_val;
Robin Holt7339ff82006-01-14 13:20:48 -08002112 } else if (!strcmp(this_char,"mpol")) {
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002113 if (shmem_parse_mpol(value,policy,policy_nodes))
Robin Holt7339ff82006-01-14 13:20:48 -08002114 goto bad_val;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002115 } else {
2116 printk(KERN_ERR "tmpfs: Bad mount option %s\n",
2117 this_char);
2118 return 1;
2119 }
2120 }
2121 return 0;
2122
2123bad_val:
2124 printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
2125 value, this_char);
2126 return 1;
2127
2128}
2129
2130static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
2131{
2132 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002133 unsigned long max_blocks = sbinfo->max_blocks;
2134 unsigned long max_inodes = sbinfo->max_inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002135 int policy = sbinfo->policy;
2136 nodemask_t policy_nodes = sbinfo->policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002137 unsigned long blocks;
2138 unsigned long inodes;
2139 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002140
Robin Holt7339ff82006-01-14 13:20:48 -08002141 if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks,
2142 &max_inodes, &policy, &policy_nodes))
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002143 return error;
2144
2145 spin_lock(&sbinfo->stat_lock);
2146 blocks = sbinfo->max_blocks - sbinfo->free_blocks;
2147 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
2148 if (max_blocks < blocks)
2149 goto out;
2150 if (max_inodes < inodes)
2151 goto out;
2152 /*
2153 * Those tests also disallow limited->unlimited while any are in
2154 * use, so i_blocks will always be zero when max_blocks is zero;
2155 * but we must separately disallow unlimited->limited, because
2156 * in that case we have no record of how much is already in use.
2157 */
2158 if (max_blocks && !sbinfo->max_blocks)
2159 goto out;
2160 if (max_inodes && !sbinfo->max_inodes)
2161 goto out;
2162
2163 error = 0;
2164 sbinfo->max_blocks = max_blocks;
2165 sbinfo->free_blocks = max_blocks - blocks;
2166 sbinfo->max_inodes = max_inodes;
2167 sbinfo->free_inodes = max_inodes - inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002168 sbinfo->policy = policy;
2169 sbinfo->policy_nodes = policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002170out:
2171 spin_unlock(&sbinfo->stat_lock);
2172 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002173}
2174#endif
2175
2176static void shmem_put_super(struct super_block *sb)
2177{
2178 kfree(sb->s_fs_info);
2179 sb->s_fs_info = NULL;
2180}
2181
Linus Torvalds1da177e2005-04-16 15:20:36 -07002182static int shmem_fill_super(struct super_block *sb,
2183 void *data, int silent)
2184{
2185 struct inode *inode;
2186 struct dentry *root;
2187 int mode = S_IRWXUGO | S_ISVTX;
2188 uid_t uid = current->fsuid;
2189 gid_t gid = current->fsgid;
2190 int err = -ENOMEM;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002191 struct shmem_sb_info *sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002192 unsigned long blocks = 0;
2193 unsigned long inodes = 0;
Robin Holt7339ff82006-01-14 13:20:48 -08002194 int policy = MPOL_DEFAULT;
2195 nodemask_t policy_nodes = node_online_map;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002196
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002197#ifdef CONFIG_TMPFS
Linus Torvalds1da177e2005-04-16 15:20:36 -07002198 /*
2199 * Per default we only allow half of the physical ram per
2200 * tmpfs instance, limiting inodes to one per page of lowmem;
2201 * but the internal instance is left unlimited.
2202 */
2203 if (!(sb->s_flags & MS_NOUSER)) {
2204 blocks = totalram_pages / 2;
2205 inodes = totalram_pages - totalhigh_pages;
2206 if (inodes > blocks)
2207 inodes = blocks;
Robin Holt7339ff82006-01-14 13:20:48 -08002208 if (shmem_parse_options(data, &mode, &uid, &gid, &blocks,
2209 &inodes, &policy, &policy_nodes))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 return -EINVAL;
2211 }
David M. Grimes91828a42006-10-17 00:09:45 -07002212 sb->s_export_op = &shmem_export_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213#else
2214 sb->s_flags |= MS_NOUSER;
2215#endif
2216
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002217 /* Round up to L1_CACHE_BYTES to resist false sharing */
2218 sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
2219 L1_CACHE_BYTES), GFP_KERNEL);
2220 if (!sbinfo)
2221 return -ENOMEM;
2222
2223 spin_lock_init(&sbinfo->stat_lock);
2224 sbinfo->max_blocks = blocks;
2225 sbinfo->free_blocks = blocks;
2226 sbinfo->max_inodes = inodes;
2227 sbinfo->free_inodes = inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002228 sbinfo->policy = policy;
2229 sbinfo->policy_nodes = policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002230
2231 sb->s_fs_info = sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002232 sb->s_maxbytes = SHMEM_MAX_BYTES;
2233 sb->s_blocksize = PAGE_CACHE_SIZE;
2234 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2235 sb->s_magic = TMPFS_MAGIC;
2236 sb->s_op = &shmem_ops;
Robin H. Johnsoncfd95a92006-06-12 21:50:25 +01002237 sb->s_time_gran = 1;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002238#ifdef CONFIG_TMPFS_POSIX_ACL
2239 sb->s_xattr = shmem_xattr_handlers;
2240 sb->s_flags |= MS_POSIXACL;
2241#endif
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002242
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243 inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
2244 if (!inode)
2245 goto failed;
2246 inode->i_uid = uid;
2247 inode->i_gid = gid;
2248 root = d_alloc_root(inode);
2249 if (!root)
2250 goto failed_iput;
2251 sb->s_root = root;
2252 return 0;
2253
2254failed_iput:
2255 iput(inode);
2256failed:
2257 shmem_put_super(sb);
2258 return err;
2259}
2260
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002261static struct kmem_cache *shmem_inode_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262
2263static struct inode *shmem_alloc_inode(struct super_block *sb)
2264{
2265 struct shmem_inode_info *p;
2266 p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, SLAB_KERNEL);
2267 if (!p)
2268 return NULL;
2269 return &p->vfs_inode;
2270}
2271
2272static void shmem_destroy_inode(struct inode *inode)
2273{
2274 if ((inode->i_mode & S_IFMT) == S_IFREG) {
2275 /* only struct inode is valid if it's an inline symlink */
2276 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
2277 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002278 shmem_acl_destroy_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002279 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
2280}
2281
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002282static void init_once(void *foo, struct kmem_cache *cachep,
2283 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284{
2285 struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
2286
2287 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
2288 SLAB_CTOR_CONSTRUCTOR) {
2289 inode_init_once(&p->vfs_inode);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002290#ifdef CONFIG_TMPFS_POSIX_ACL
2291 p->i_acl = NULL;
2292 p->i_default_acl = NULL;
2293#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294 }
2295}
2296
2297static int init_inodecache(void)
2298{
2299 shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
2300 sizeof(struct shmem_inode_info),
2301 0, 0, init_once, NULL);
2302 if (shmem_inode_cachep == NULL)
2303 return -ENOMEM;
2304 return 0;
2305}
2306
2307static void destroy_inodecache(void)
2308{
Alexey Dobriyan1a1d92c2006-09-27 01:49:40 -07002309 kmem_cache_destroy(shmem_inode_cachep);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310}
2311
Christoph Hellwigf5e54d62006-06-28 04:26:44 -07002312static const struct address_space_operations shmem_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002313 .writepage = shmem_writepage,
2314 .set_page_dirty = __set_page_dirty_nobuffers,
2315#ifdef CONFIG_TMPFS
2316 .prepare_write = shmem_prepare_write,
2317 .commit_write = simple_commit_write,
2318#endif
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -07002319 .migratepage = migrate_page,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320};
2321
2322static struct file_operations shmem_file_operations = {
2323 .mmap = shmem_mmap,
2324#ifdef CONFIG_TMPFS
2325 .llseek = generic_file_llseek,
2326 .read = shmem_file_read,
2327 .write = shmem_file_write,
2328 .fsync = simple_sync_file,
2329 .sendfile = shmem_file_sendfile,
2330#endif
2331};
2332
2333static struct inode_operations shmem_inode_operations = {
2334 .truncate = shmem_truncate,
2335 .setattr = shmem_notify_change,
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002336 .truncate_range = shmem_truncate_range,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002337#ifdef CONFIG_TMPFS_POSIX_ACL
2338 .setxattr = generic_setxattr,
2339 .getxattr = generic_getxattr,
2340 .listxattr = generic_listxattr,
2341 .removexattr = generic_removexattr,
2342 .permission = shmem_permission,
2343#endif
2344
Linus Torvalds1da177e2005-04-16 15:20:36 -07002345};
2346
2347static struct inode_operations shmem_dir_inode_operations = {
2348#ifdef CONFIG_TMPFS
2349 .create = shmem_create,
2350 .lookup = simple_lookup,
2351 .link = shmem_link,
2352 .unlink = shmem_unlink,
2353 .symlink = shmem_symlink,
2354 .mkdir = shmem_mkdir,
2355 .rmdir = shmem_rmdir,
2356 .mknod = shmem_mknod,
2357 .rename = shmem_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358#endif
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002359#ifdef CONFIG_TMPFS_POSIX_ACL
2360 .setattr = shmem_notify_change,
2361 .setxattr = generic_setxattr,
2362 .getxattr = generic_getxattr,
2363 .listxattr = generic_listxattr,
2364 .removexattr = generic_removexattr,
2365 .permission = shmem_permission,
2366#endif
2367};
2368
2369static struct inode_operations shmem_special_inode_operations = {
2370#ifdef CONFIG_TMPFS_POSIX_ACL
2371 .setattr = shmem_notify_change,
2372 .setxattr = generic_setxattr,
2373 .getxattr = generic_getxattr,
2374 .listxattr = generic_listxattr,
2375 .removexattr = generic_removexattr,
2376 .permission = shmem_permission,
2377#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378};
2379
2380static struct super_operations shmem_ops = {
2381 .alloc_inode = shmem_alloc_inode,
2382 .destroy_inode = shmem_destroy_inode,
2383#ifdef CONFIG_TMPFS
2384 .statfs = shmem_statfs,
2385 .remount_fs = shmem_remount_fs,
2386#endif
2387 .delete_inode = shmem_delete_inode,
2388 .drop_inode = generic_delete_inode,
2389 .put_super = shmem_put_super,
2390};
2391
2392static struct vm_operations_struct shmem_vm_ops = {
2393 .nopage = shmem_nopage,
2394 .populate = shmem_populate,
2395#ifdef CONFIG_NUMA
2396 .set_policy = shmem_set_policy,
2397 .get_policy = shmem_get_policy,
2398#endif
2399};
2400
2401
David Howells454e2392006-06-23 02:02:57 -07002402static int shmem_get_sb(struct file_system_type *fs_type,
2403 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002404{
David Howells454e2392006-06-23 02:02:57 -07002405 return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002406}
2407
2408static struct file_system_type tmpfs_fs_type = {
2409 .owner = THIS_MODULE,
2410 .name = "tmpfs",
2411 .get_sb = shmem_get_sb,
2412 .kill_sb = kill_litter_super,
2413};
2414static struct vfsmount *shm_mnt;
2415
2416static int __init init_tmpfs(void)
2417{
2418 int error;
2419
2420 error = init_inodecache();
2421 if (error)
2422 goto out3;
2423
2424 error = register_filesystem(&tmpfs_fs_type);
2425 if (error) {
2426 printk(KERN_ERR "Could not register tmpfs\n");
2427 goto out2;
2428 }
Greg Kroah-Hartman95dc1122005-06-20 21:15:16 -07002429
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -04002430 shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431 tmpfs_fs_type.name, NULL);
2432 if (IS_ERR(shm_mnt)) {
2433 error = PTR_ERR(shm_mnt);
2434 printk(KERN_ERR "Could not kern_mount tmpfs\n");
2435 goto out1;
2436 }
2437 return 0;
2438
2439out1:
2440 unregister_filesystem(&tmpfs_fs_type);
2441out2:
2442 destroy_inodecache();
2443out3:
2444 shm_mnt = ERR_PTR(error);
2445 return error;
2446}
2447module_init(init_tmpfs)
2448
2449/*
2450 * shmem_file_setup - get an unlinked file living in tmpfs
2451 *
2452 * @name: name for dentry (to be seen in /proc/<pid>/maps
2453 * @size: size to be set for the file
2454 *
2455 */
2456struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
2457{
2458 int error;
2459 struct file *file;
2460 struct inode *inode;
2461 struct dentry *dentry, *root;
2462 struct qstr this;
2463
2464 if (IS_ERR(shm_mnt))
2465 return (void *)shm_mnt;
2466
2467 if (size < 0 || size > SHMEM_MAX_BYTES)
2468 return ERR_PTR(-EINVAL);
2469
2470 if (shmem_acct_size(flags, size))
2471 return ERR_PTR(-ENOMEM);
2472
2473 error = -ENOMEM;
2474 this.name = name;
2475 this.len = strlen(name);
2476 this.hash = 0; /* will go */
2477 root = shm_mnt->mnt_root;
2478 dentry = d_alloc(root, &this);
2479 if (!dentry)
2480 goto put_memory;
2481
2482 error = -ENFILE;
2483 file = get_empty_filp();
2484 if (!file)
2485 goto put_dentry;
2486
2487 error = -ENOSPC;
2488 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
2489 if (!inode)
2490 goto close_file;
2491
2492 SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
2493 d_instantiate(dentry, inode);
2494 inode->i_size = size;
2495 inode->i_nlink = 0; /* It is unlinked */
2496 file->f_vfsmnt = mntget(shm_mnt);
2497 file->f_dentry = dentry;
2498 file->f_mapping = inode->i_mapping;
2499 file->f_op = &shmem_file_operations;
2500 file->f_mode = FMODE_WRITE | FMODE_READ;
2501 return file;
2502
2503close_file:
2504 put_filp(file);
2505put_dentry:
2506 dput(dentry);
2507put_memory:
2508 shmem_unacct_size(flags, size);
2509 return ERR_PTR(error);
2510}
2511
2512/*
2513 * shmem_zero_setup - setup a shared anonymous mapping
2514 *
2515 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2516 */
2517int shmem_zero_setup(struct vm_area_struct *vma)
2518{
2519 struct file *file;
2520 loff_t size = vma->vm_end - vma->vm_start;
2521
2522 file = shmem_file_setup("dev/zero", size, vma->vm_flags);
2523 if (IS_ERR(file))
2524 return PTR_ERR(file);
2525
2526 if (vma->vm_file)
2527 fput(vma->vm_file);
2528 vma->vm_file = file;
2529 vma->vm_ops = &shmem_vm_ops;
2530 return 0;
2531}