blob: 90b576cbc06e40fb0f43d06f37f5ef24deee9f13 [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>
Christoph Hellwiga5694252007-07-17 04:04:28 -070030#include <linux/exportfs.h>
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070031#include <linux/generic_acl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/mm.h>
33#include <linux/mman.h>
34#include <linux/file.h>
35#include <linux/swap.h>
36#include <linux/pagemap.h>
37#include <linux/string.h>
38#include <linux/slab.h>
39#include <linux/backing-dev.h>
40#include <linux/shmem_fs.h>
41#include <linux/mount.h>
42#include <linux/writeback.h>
43#include <linux/vfs.h>
44#include <linux/blkdev.h>
45#include <linux/security.h>
46#include <linux/swapops.h>
47#include <linux/mempolicy.h>
48#include <linux/namei.h>
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +000049#include <linux/ctype.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070050#include <linux/migrate.h>
Christoph Lameterc1f60a52006-09-25 23:31:11 -070051#include <linux/highmem.h>
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -080052#include <linux/seq_file.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070053
Linus Torvalds1da177e2005-04-16 15:20:36 -070054#include <asm/uaccess.h>
55#include <asm/div64.h>
56#include <asm/pgtable.h>
57
58/* This magic number is used in glibc for posix shared memory */
59#define TMPFS_MAGIC 0x01021994
60
61#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
62#define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
63#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
64
65#define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
66#define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT)
67
68#define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
69
70/* info->flags needs VM_flags to handle pagein/truncate races efficiently */
71#define SHMEM_PAGEIN VM_READ
72#define SHMEM_TRUNCATE VM_WRITE
73
74/* Definition to limit shmem_truncate's steps between cond_rescheds */
75#define LATENCY_LIMIT 64
76
77/* Pretend that each entry is of this size in directory's i_size */
78#define BOGO_DIRENT_SIZE 20
79
Linus Torvalds1da177e2005-04-16 15:20:36 -070080/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
81enum sgp_type {
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 SGP_READ, /* don't exceed i_size, don't allocate page */
83 SGP_CACHE, /* don't exceed i_size, may allocate page */
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -080084 SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 SGP_WRITE, /* may exceed i_size, may allocate page */
86};
87
Andrew Mortonb76db732008-02-08 04:21:49 -080088#ifdef CONFIG_TMPFS
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -080089static unsigned long shmem_default_max_blocks(void)
90{
91 return totalram_pages / 2;
92}
93
94static unsigned long shmem_default_max_inodes(void)
95{
96 return min(totalram_pages - totalhigh_pages, totalram_pages / 2);
97}
Andrew Mortonb76db732008-02-08 04:21:49 -080098#endif
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -080099
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100static int shmem_getpage(struct inode *inode, unsigned long idx,
101 struct page **pagep, enum sgp_type sgp, int *type);
102
Al Viro6daa0e22005-10-21 03:18:50 -0400103static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104{
105 /*
106 * The above definition of ENTRIES_PER_PAGE, and the use of
107 * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
108 * might be reconsidered if it ever diverges from PAGE_SIZE.
Mel Gorman769848c2007-07-17 04:03:05 -0700109 *
Mel Gormane12ba742007-10-16 01:25:52 -0700110 * Mobility flags are masked out as swap vectors cannot move
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 */
Mel Gormane12ba742007-10-16 01:25:52 -0700112 return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO,
Mel Gorman769848c2007-07-17 04:03:05 -0700113 PAGE_CACHE_SHIFT-PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114}
115
116static inline void shmem_dir_free(struct page *page)
117{
118 __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT);
119}
120
121static struct page **shmem_dir_map(struct page *page)
122{
123 return (struct page **)kmap_atomic(page, KM_USER0);
124}
125
126static inline void shmem_dir_unmap(struct page **dir)
127{
128 kunmap_atomic(dir, KM_USER0);
129}
130
131static swp_entry_t *shmem_swp_map(struct page *page)
132{
133 return (swp_entry_t *)kmap_atomic(page, KM_USER1);
134}
135
136static inline void shmem_swp_balance_unmap(void)
137{
138 /*
139 * When passing a pointer to an i_direct entry, to code which
140 * also handles indirect entries and so will shmem_swp_unmap,
141 * we must arrange for the preempt count to remain in balance.
142 * What kmap_atomic of a lowmem page does depends on config
143 * and architecture, so pretend to kmap_atomic some lowmem page.
144 */
145 (void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
146}
147
148static inline void shmem_swp_unmap(swp_entry_t *entry)
149{
150 kunmap_atomic(entry, KM_USER1);
151}
152
153static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
154{
155 return sb->s_fs_info;
156}
157
158/*
159 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
160 * for shared memory and for shared anonymous (/dev/zero) mappings
161 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
162 * consistent with the pre-accounting of private mappings ...
163 */
164static inline int shmem_acct_size(unsigned long flags, loff_t size)
165{
166 return (flags & VM_ACCOUNT)?
167 security_vm_enough_memory(VM_ACCT(size)): 0;
168}
169
170static inline void shmem_unacct_size(unsigned long flags, loff_t size)
171{
172 if (flags & VM_ACCOUNT)
173 vm_unacct_memory(VM_ACCT(size));
174}
175
176/*
177 * ... whereas tmpfs objects are accounted incrementally as
178 * pages are allocated, in order to allow huge sparse files.
179 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
180 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
181 */
182static inline int shmem_acct_block(unsigned long flags)
183{
184 return (flags & VM_ACCOUNT)?
185 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE));
186}
187
188static inline void shmem_unacct_blocks(unsigned long flags, long pages)
189{
190 if (!(flags & VM_ACCOUNT))
191 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
192}
193
Hugh Dickins759b9772007-03-05 00:30:28 -0800194static const struct super_operations shmem_ops;
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700195static const struct address_space_operations shmem_aops;
Helge Deller15ad7cd2006-12-06 20:40:36 -0800196static const struct file_operations shmem_file_operations;
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800197static const struct inode_operations shmem_inode_operations;
198static const struct inode_operations shmem_dir_inode_operations;
199static const struct inode_operations shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200static struct vm_operations_struct shmem_vm_ops;
201
Ravikiran G Thirumalai6c231b72005-09-06 15:17:45 -0700202static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 .ra_pages = 0, /* No readahead */
204 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
205 .unplug_io_fn = default_unplug_io_fn,
206};
207
208static LIST_HEAD(shmem_swaplist);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800209static DEFINE_MUTEX(shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
211static void shmem_free_blocks(struct inode *inode, long pages)
212{
213 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700214 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 spin_lock(&sbinfo->stat_lock);
216 sbinfo->free_blocks += pages;
217 inode->i_blocks -= pages*BLOCKS_PER_PAGE;
218 spin_unlock(&sbinfo->stat_lock);
219 }
220}
221
Pavel Emelyanov5b04c682008-02-04 22:28:47 -0800222static int shmem_reserve_inode(struct super_block *sb)
223{
224 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
225 if (sbinfo->max_inodes) {
226 spin_lock(&sbinfo->stat_lock);
227 if (!sbinfo->free_inodes) {
228 spin_unlock(&sbinfo->stat_lock);
229 return -ENOSPC;
230 }
231 sbinfo->free_inodes--;
232 spin_unlock(&sbinfo->stat_lock);
233 }
234 return 0;
235}
236
237static void shmem_free_inode(struct super_block *sb)
238{
239 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
240 if (sbinfo->max_inodes) {
241 spin_lock(&sbinfo->stat_lock);
242 sbinfo->free_inodes++;
243 spin_unlock(&sbinfo->stat_lock);
244 }
245}
246
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247/*
248 * shmem_recalc_inode - recalculate the size of an inode
249 *
250 * @inode: inode to recalc
251 *
252 * We have to calculate the free blocks since the mm can drop
253 * undirtied hole pages behind our back.
254 *
255 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
256 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
257 *
258 * It has to be called with the spinlock held.
259 */
260static void shmem_recalc_inode(struct inode *inode)
261{
262 struct shmem_inode_info *info = SHMEM_I(inode);
263 long freed;
264
265 freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
266 if (freed > 0) {
267 info->alloced -= freed;
268 shmem_unacct_blocks(info->flags, freed);
269 shmem_free_blocks(inode, freed);
270 }
271}
272
273/*
274 * shmem_swp_entry - find the swap vector position in the info structure
275 *
276 * @info: info structure for the inode
277 * @index: index of the page to find
278 * @page: optional page to add to the structure. Has to be preset to
279 * all zeros
280 *
281 * If there is no space allocated yet it will return NULL when
282 * page is NULL, else it will use the page for the needed block,
283 * setting it to NULL on return to indicate that it has been used.
284 *
285 * The swap vector is organized the following way:
286 *
287 * There are SHMEM_NR_DIRECT entries directly stored in the
288 * shmem_inode_info structure. So small files do not need an addional
289 * allocation.
290 *
291 * For pages with index > SHMEM_NR_DIRECT there is the pointer
292 * i_indirect which points to a page which holds in the first half
293 * doubly indirect blocks, in the second half triple indirect blocks:
294 *
295 * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the
296 * following layout (for SHMEM_NR_DIRECT == 16):
297 *
298 * i_indirect -> dir --> 16-19
299 * | +-> 20-23
300 * |
301 * +-->dir2 --> 24-27
302 * | +-> 28-31
303 * | +-> 32-35
304 * | +-> 36-39
305 * |
306 * +-->dir3 --> 40-43
307 * +-> 44-47
308 * +-> 48-51
309 * +-> 52-55
310 */
311static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page)
312{
313 unsigned long offset;
314 struct page **dir;
315 struct page *subdir;
316
317 if (index < SHMEM_NR_DIRECT) {
318 shmem_swp_balance_unmap();
319 return info->i_direct+index;
320 }
321 if (!info->i_indirect) {
322 if (page) {
323 info->i_indirect = *page;
324 *page = NULL;
325 }
326 return NULL; /* need another page */
327 }
328
329 index -= SHMEM_NR_DIRECT;
330 offset = index % ENTRIES_PER_PAGE;
331 index /= ENTRIES_PER_PAGE;
332 dir = shmem_dir_map(info->i_indirect);
333
334 if (index >= ENTRIES_PER_PAGE/2) {
335 index -= ENTRIES_PER_PAGE/2;
336 dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE;
337 index %= ENTRIES_PER_PAGE;
338 subdir = *dir;
339 if (!subdir) {
340 if (page) {
341 *dir = *page;
342 *page = NULL;
343 }
344 shmem_dir_unmap(dir);
345 return NULL; /* need another page */
346 }
347 shmem_dir_unmap(dir);
348 dir = shmem_dir_map(subdir);
349 }
350
351 dir += index;
352 subdir = *dir;
353 if (!subdir) {
354 if (!page || !(subdir = *page)) {
355 shmem_dir_unmap(dir);
356 return NULL; /* need a page */
357 }
358 *dir = subdir;
359 *page = NULL;
360 }
361 shmem_dir_unmap(dir);
362 return shmem_swp_map(subdir) + offset;
363}
364
365static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
366{
367 long incdec = value? 1: -1;
368
369 entry->val = value;
370 info->swapped += incdec;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700371 if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
372 struct page *page = kmap_atomic_to_page(entry);
373 set_page_private(page, page_private(page) + incdec);
374 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375}
376
377/*
378 * shmem_swp_alloc - get the position of the swap entry for the page.
379 * If it does not exist allocate the entry.
380 *
381 * @info: info structure for the inode
382 * @index: index of the page to find
383 * @sgp: check and recheck i_size? skip allocation?
384 */
385static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp)
386{
387 struct inode *inode = &info->vfs_inode;
388 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
389 struct page *page = NULL;
390 swp_entry_t *entry;
391
392 if (sgp != SGP_WRITE &&
393 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
394 return ERR_PTR(-EINVAL);
395
396 while (!(entry = shmem_swp_entry(info, index, &page))) {
397 if (sgp == SGP_READ)
398 return shmem_swp_map(ZERO_PAGE(0));
399 /*
400 * Test free_blocks against 1 not 0, since we have 1 data
401 * page (and perhaps indirect index pages) yet to allocate:
402 * a waste to allocate index if we cannot allocate data.
403 */
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700404 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 spin_lock(&sbinfo->stat_lock);
406 if (sbinfo->free_blocks <= 1) {
407 spin_unlock(&sbinfo->stat_lock);
408 return ERR_PTR(-ENOSPC);
409 }
410 sbinfo->free_blocks--;
411 inode->i_blocks += BLOCKS_PER_PAGE;
412 spin_unlock(&sbinfo->stat_lock);
413 }
414
415 spin_unlock(&info->lock);
Mel Gorman769848c2007-07-17 04:03:05 -0700416 page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping));
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700417 if (page)
418 set_page_private(page, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 spin_lock(&info->lock);
420
421 if (!page) {
422 shmem_free_blocks(inode, 1);
423 return ERR_PTR(-ENOMEM);
424 }
425 if (sgp != SGP_WRITE &&
426 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
427 entry = ERR_PTR(-EINVAL);
428 break;
429 }
430 if (info->next_index <= index)
431 info->next_index = index + 1;
432 }
433 if (page) {
434 /* another task gave its page, or truncated the file */
435 shmem_free_blocks(inode, 1);
436 shmem_dir_free(page);
437 }
438 if (info->next_index <= index && !IS_ERR(entry))
439 info->next_index = index + 1;
440 return entry;
441}
442
443/*
444 * shmem_free_swp - free some swap entries in a directory
445 *
Hugh Dickins1ae70002007-03-29 01:20:36 -0700446 * @dir: pointer to the directory
447 * @edir: pointer after last entry of the directory
448 * @punch_lock: pointer to spinlock when needed for the holepunch case
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 */
Hugh Dickins1ae70002007-03-29 01:20:36 -0700450static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
451 spinlock_t *punch_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452{
Hugh Dickins1ae70002007-03-29 01:20:36 -0700453 spinlock_t *punch_unlock = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 swp_entry_t *ptr;
455 int freed = 0;
456
457 for (ptr = dir; ptr < edir; ptr++) {
458 if (ptr->val) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700459 if (unlikely(punch_lock)) {
460 punch_unlock = punch_lock;
461 punch_lock = NULL;
462 spin_lock(punch_unlock);
463 if (!ptr->val)
464 continue;
465 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 free_swap_and_cache(*ptr);
467 *ptr = (swp_entry_t){0};
468 freed++;
469 }
470 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700471 if (punch_unlock)
472 spin_unlock(punch_unlock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 return freed;
474}
475
Hugh Dickins1ae70002007-03-29 01:20:36 -0700476static int shmem_map_and_free_swp(struct page *subdir, int offset,
477 int limit, struct page ***dir, spinlock_t *punch_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478{
479 swp_entry_t *ptr;
480 int freed = 0;
481
482 ptr = shmem_swp_map(subdir);
483 for (; offset < limit; offset += LATENCY_LIMIT) {
484 int size = limit - offset;
485 if (size > LATENCY_LIMIT)
486 size = LATENCY_LIMIT;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700487 freed += shmem_free_swp(ptr+offset, ptr+offset+size,
488 punch_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 if (need_resched()) {
490 shmem_swp_unmap(ptr);
491 if (*dir) {
492 shmem_dir_unmap(*dir);
493 *dir = NULL;
494 }
495 cond_resched();
496 ptr = shmem_swp_map(subdir);
497 }
498 }
499 shmem_swp_unmap(ptr);
500 return freed;
501}
502
503static void shmem_free_pages(struct list_head *next)
504{
505 struct page *page;
506 int freed = 0;
507
508 do {
509 page = container_of(next, struct page, lru);
510 next = next->next;
511 shmem_dir_free(page);
512 freed++;
513 if (freed >= LATENCY_LIMIT) {
514 cond_resched();
515 freed = 0;
516 }
517 } while (next);
518}
519
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800520static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521{
522 struct shmem_inode_info *info = SHMEM_I(inode);
523 unsigned long idx;
524 unsigned long size;
525 unsigned long limit;
526 unsigned long stage;
527 unsigned long diroff;
528 struct page **dir;
529 struct page *topdir;
530 struct page *middir;
531 struct page *subdir;
532 swp_entry_t *ptr;
533 LIST_HEAD(pages_to_free);
534 long nr_pages_to_free = 0;
535 long nr_swaps_freed = 0;
536 int offset;
537 int freed;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700538 int punch_hole;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700539 spinlock_t *needs_lock;
540 spinlock_t *punch_lock;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700541 unsigned long upper_limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
543 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800544 idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 if (idx >= info->next_index)
546 return;
547
548 spin_lock(&info->lock);
549 info->flags |= SHMEM_TRUNCATE;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800550 if (likely(end == (loff_t) -1)) {
551 limit = info->next_index;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700552 upper_limit = SHMEM_MAX_INDEX;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800553 info->next_index = idx;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700554 needs_lock = NULL;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700555 punch_hole = 0;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800556 } else {
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700557 if (end + 1 >= inode->i_size) { /* we may free a little more */
558 limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >>
559 PAGE_CACHE_SHIFT;
560 upper_limit = SHMEM_MAX_INDEX;
561 } else {
562 limit = (end + 1) >> PAGE_CACHE_SHIFT;
563 upper_limit = limit;
564 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700565 needs_lock = &info->lock;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800566 punch_hole = 1;
567 }
568
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 topdir = info->i_indirect;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800570 if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 info->i_indirect = NULL;
572 nr_pages_to_free++;
573 list_add(&topdir->lru, &pages_to_free);
574 }
575 spin_unlock(&info->lock);
576
577 if (info->swapped && idx < SHMEM_NR_DIRECT) {
578 ptr = info->i_direct;
579 size = limit;
580 if (size > SHMEM_NR_DIRECT)
581 size = SHMEM_NR_DIRECT;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700582 nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 }
Badari Pulavarty92a3d032006-12-22 01:06:23 -0800584
585 /*
586 * If there are no indirect blocks or we are punching a hole
587 * below indirect blocks, nothing to be done.
588 */
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700589 if (!topdir || limit <= SHMEM_NR_DIRECT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 goto done2;
591
Hugh Dickins1ae70002007-03-29 01:20:36 -0700592 /*
593 * The truncation case has already dropped info->lock, and we're safe
594 * because i_size and next_index have already been lowered, preventing
595 * access beyond. But in the punch_hole case, we still need to take
596 * the lock when updating the swap directory, because there might be
597 * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or
598 * shmem_writepage. However, whenever we find we can remove a whole
599 * directory page (not at the misaligned start or end of the range),
600 * we first NULLify its pointer in the level above, and then have no
601 * need to take the lock when updating its contents: needs_lock and
602 * punch_lock (either pointing to info->lock or NULL) manage this.
603 */
604
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700605 upper_limit -= SHMEM_NR_DIRECT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 limit -= SHMEM_NR_DIRECT;
607 idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
608 offset = idx % ENTRIES_PER_PAGE;
609 idx -= offset;
610
611 dir = shmem_dir_map(topdir);
612 stage = ENTRIES_PER_PAGEPAGE/2;
613 if (idx < ENTRIES_PER_PAGEPAGE/2) {
614 middir = topdir;
615 diroff = idx/ENTRIES_PER_PAGE;
616 } else {
617 dir += ENTRIES_PER_PAGE/2;
618 dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
619 while (stage <= idx)
620 stage += ENTRIES_PER_PAGEPAGE;
621 middir = *dir;
622 if (*dir) {
623 diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
624 ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700625 if (!diroff && !offset && upper_limit >= stage) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700626 if (needs_lock) {
627 spin_lock(needs_lock);
628 *dir = NULL;
629 spin_unlock(needs_lock);
630 needs_lock = NULL;
631 } else
632 *dir = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 nr_pages_to_free++;
634 list_add(&middir->lru, &pages_to_free);
635 }
636 shmem_dir_unmap(dir);
637 dir = shmem_dir_map(middir);
638 } else {
639 diroff = 0;
640 offset = 0;
641 idx = stage;
642 }
643 }
644
645 for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
646 if (unlikely(idx == stage)) {
647 shmem_dir_unmap(dir);
648 dir = shmem_dir_map(topdir) +
649 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
650 while (!*dir) {
651 dir++;
652 idx += ENTRIES_PER_PAGEPAGE;
653 if (idx >= limit)
654 goto done1;
655 }
656 stage = idx + ENTRIES_PER_PAGEPAGE;
657 middir = *dir;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700658 if (punch_hole)
659 needs_lock = &info->lock;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700660 if (upper_limit >= stage) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700661 if (needs_lock) {
662 spin_lock(needs_lock);
663 *dir = NULL;
664 spin_unlock(needs_lock);
665 needs_lock = NULL;
666 } else
667 *dir = NULL;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700668 nr_pages_to_free++;
669 list_add(&middir->lru, &pages_to_free);
670 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 shmem_dir_unmap(dir);
672 cond_resched();
673 dir = shmem_dir_map(middir);
674 diroff = 0;
675 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700676 punch_lock = needs_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 subdir = dir[diroff];
Hugh Dickins1ae70002007-03-29 01:20:36 -0700678 if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) {
679 if (needs_lock) {
680 spin_lock(needs_lock);
681 dir[diroff] = NULL;
682 spin_unlock(needs_lock);
683 punch_lock = NULL;
684 } else
685 dir[diroff] = NULL;
686 nr_pages_to_free++;
687 list_add(&subdir->lru, &pages_to_free);
688 }
689 if (subdir && page_private(subdir) /* has swap entries */) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 size = limit - idx;
691 if (size > ENTRIES_PER_PAGE)
692 size = ENTRIES_PER_PAGE;
693 freed = shmem_map_and_free_swp(subdir,
Hugh Dickins1ae70002007-03-29 01:20:36 -0700694 offset, size, &dir, punch_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 if (!dir)
696 dir = shmem_dir_map(middir);
697 nr_swaps_freed += freed;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700698 if (offset || punch_lock) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 spin_lock(&info->lock);
Hugh Dickins1ae70002007-03-29 01:20:36 -0700700 set_page_private(subdir,
701 page_private(subdir) - freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 spin_unlock(&info->lock);
Hugh Dickins1ae70002007-03-29 01:20:36 -0700703 } else
704 BUG_ON(page_private(subdir) != freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700706 offset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 }
708done1:
709 shmem_dir_unmap(dir);
710done2:
711 if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
712 /*
713 * Call truncate_inode_pages again: racing shmem_unuse_inode
714 * may have swizzled a page in from swap since vmtruncate or
715 * generic_delete_inode did it, before we lowered next_index.
716 * Also, though shmem_getpage checks i_size before adding to
717 * cache, no recheck after: so fix the narrow window there too.
Hugh Dickins16a10012007-03-29 01:20:37 -0700718 *
719 * Recalling truncate_inode_pages_range and unmap_mapping_range
720 * every time for punch_hole (which never got a chance to clear
721 * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive,
722 * yet hardly ever necessary: try to optimize them out later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 */
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800724 truncate_inode_pages_range(inode->i_mapping, start, end);
Hugh Dickins16a10012007-03-29 01:20:37 -0700725 if (punch_hole)
726 unmap_mapping_range(inode->i_mapping, start,
727 end - start, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 }
729
730 spin_lock(&info->lock);
731 info->flags &= ~SHMEM_TRUNCATE;
732 info->swapped -= nr_swaps_freed;
733 if (nr_pages_to_free)
734 shmem_free_blocks(inode, nr_pages_to_free);
735 shmem_recalc_inode(inode);
736 spin_unlock(&info->lock);
737
738 /*
739 * Empty swap vector directory pages to be freed?
740 */
741 if (!list_empty(&pages_to_free)) {
742 pages_to_free.prev->next = NULL;
743 shmem_free_pages(pages_to_free.next);
744 }
745}
746
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800747static void shmem_truncate(struct inode *inode)
748{
749 shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
750}
751
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
753{
754 struct inode *inode = dentry->d_inode;
755 struct page *page = NULL;
756 int error;
757
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700758 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 if (attr->ia_size < inode->i_size) {
760 /*
761 * If truncating down to a partial page, then
762 * if that page is already allocated, hold it
763 * in memory until the truncation is over, so
764 * truncate_partial_page cannnot miss it were
765 * it assigned to swap.
766 */
767 if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
768 (void) shmem_getpage(inode,
769 attr->ia_size>>PAGE_CACHE_SHIFT,
770 &page, SGP_READ, NULL);
Hugh Dickinsd3602442008-02-04 22:28:44 -0800771 if (page)
772 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 }
774 /*
775 * Reset SHMEM_PAGEIN flag so that shmem_truncate can
776 * detect if any pages might have been added to cache
777 * after truncate_inode_pages. But we needn't bother
778 * if it's being fully truncated to zero-length: the
779 * nrpages check is efficient enough in that case.
780 */
781 if (attr->ia_size) {
782 struct shmem_inode_info *info = SHMEM_I(inode);
783 spin_lock(&info->lock);
784 info->flags &= ~SHMEM_PAGEIN;
785 spin_unlock(&info->lock);
786 }
787 }
788 }
789
790 error = inode_change_ok(inode, attr);
791 if (!error)
792 error = inode_setattr(inode, attr);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700793#ifdef CONFIG_TMPFS_POSIX_ACL
794 if (!error && (attr->ia_valid & ATTR_MODE))
795 error = generic_acl_chmod(inode, &shmem_acl_ops);
796#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 if (page)
798 page_cache_release(page);
799 return error;
800}
801
802static void shmem_delete_inode(struct inode *inode)
803{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 struct shmem_inode_info *info = SHMEM_I(inode);
805
806 if (inode->i_op->truncate == shmem_truncate) {
Mark Fashehfef26652005-09-09 13:01:31 -0700807 truncate_inode_pages(inode->i_mapping, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 shmem_unacct_size(info->flags, inode->i_size);
809 inode->i_size = 0;
810 shmem_truncate(inode);
811 if (!list_empty(&info->swaplist)) {
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800812 mutex_lock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 list_del_init(&info->swaplist);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800814 mutex_unlock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 }
816 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700817 BUG_ON(inode->i_blocks);
Pavel Emelyanov5b04c682008-02-04 22:28:47 -0800818 shmem_free_inode(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 clear_inode(inode);
820}
821
822static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
823{
824 swp_entry_t *ptr;
825
826 for (ptr = dir; ptr < edir; ptr++) {
827 if (ptr->val == entry.val)
828 return ptr - dir;
829 }
830 return -1;
831}
832
833static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
834{
835 struct inode *inode;
836 unsigned long idx;
837 unsigned long size;
838 unsigned long limit;
839 unsigned long stage;
840 struct page **dir;
841 struct page *subdir;
842 swp_entry_t *ptr;
843 int offset;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800844 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
846 idx = 0;
847 ptr = info->i_direct;
848 spin_lock(&info->lock);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800849 if (!info->swapped) {
850 list_del_init(&info->swaplist);
851 goto lost2;
852 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 limit = info->next_index;
854 size = limit;
855 if (size > SHMEM_NR_DIRECT)
856 size = SHMEM_NR_DIRECT;
857 offset = shmem_find_swp(entry, ptr, ptr+size);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800858 if (offset >= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 goto found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 if (!info->i_indirect)
861 goto lost2;
862
863 dir = shmem_dir_map(info->i_indirect);
864 stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
865
866 for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
867 if (unlikely(idx == stage)) {
868 shmem_dir_unmap(dir-1);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800869 if (cond_resched_lock(&info->lock)) {
870 /* check it has not been truncated */
871 if (limit > info->next_index) {
872 limit = info->next_index;
873 if (idx >= limit)
874 goto lost2;
875 }
876 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 dir = shmem_dir_map(info->i_indirect) +
878 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
879 while (!*dir) {
880 dir++;
881 idx += ENTRIES_PER_PAGEPAGE;
882 if (idx >= limit)
883 goto lost1;
884 }
885 stage = idx + ENTRIES_PER_PAGEPAGE;
886 subdir = *dir;
887 shmem_dir_unmap(dir);
888 dir = shmem_dir_map(subdir);
889 }
890 subdir = *dir;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700891 if (subdir && page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 ptr = shmem_swp_map(subdir);
893 size = limit - idx;
894 if (size > ENTRIES_PER_PAGE)
895 size = ENTRIES_PER_PAGE;
896 offset = shmem_find_swp(entry, ptr, ptr+size);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800897 shmem_swp_unmap(ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 if (offset >= 0) {
899 shmem_dir_unmap(dir);
900 goto found;
901 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 }
903 }
904lost1:
905 shmem_dir_unmap(dir-1);
906lost2:
907 spin_unlock(&info->lock);
908 return 0;
909found:
910 idx += offset;
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800911 inode = igrab(&info->vfs_inode);
912 spin_unlock(&info->lock);
913
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800914 /*
915 * Move _head_ to start search for next from here.
916 * But be careful: shmem_delete_inode checks list_empty without taking
917 * mutex, and there's an instant in list_move_tail when info->swaplist
918 * would appear empty, if it were the only one on shmem_swaplist. We
919 * could avoid doing it if inode NULL; or use this minor optimization.
920 */
921 if (shmem_swaplist.next != &info->swaplist)
922 list_move_tail(&shmem_swaplist, &info->swaplist);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800923 mutex_unlock(&shmem_swaplist_mutex);
924
925 error = 1;
926 if (!inode)
927 goto out;
Hugh Dickins82369552008-02-07 00:14:22 -0800928 /* Precharge page while we can wait, compensate afterwards */
929 error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800930 if (error)
931 goto out;
Hugh Dickins82369552008-02-07 00:14:22 -0800932 error = radix_tree_preload(GFP_KERNEL);
933 if (error)
934 goto uncharge;
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800935 error = 1;
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800936
937 spin_lock(&info->lock);
938 ptr = shmem_swp_entry(info, idx, NULL);
939 if (ptr && ptr->val == entry.val)
940 error = add_to_page_cache(page, inode->i_mapping,
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800941 idx, GFP_NOWAIT);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800942 if (error == -EEXIST) {
943 struct page *filepage = find_get_page(inode->i_mapping, idx);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800944 error = 1;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800945 if (filepage) {
946 /*
947 * There might be a more uptodate page coming down
948 * from a stacked writepage: forget our swappage if so.
949 */
950 if (PageUptodate(filepage))
951 error = 0;
952 page_cache_release(filepage);
953 }
954 }
955 if (!error) {
Hugh Dickins73b12622008-02-04 22:28:50 -0800956 delete_from_swap_cache(page);
957 set_page_dirty(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 info->flags |= SHMEM_PAGEIN;
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800959 shmem_swp_set(info, ptr, 0);
960 swap_free(entry);
961 error = 1; /* not an error, but entry was found */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 }
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800963 if (ptr)
964 shmem_swp_unmap(ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 spin_unlock(&info->lock);
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800966 radix_tree_preload_end();
Hugh Dickins82369552008-02-07 00:14:22 -0800967uncharge:
968 mem_cgroup_uncharge_page(page);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800969out:
970 unlock_page(page);
971 page_cache_release(page);
972 iput(inode); /* allows for NULL */
973 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974}
975
976/*
977 * shmem_unuse() search for an eventually swapped out shmem page.
978 */
979int shmem_unuse(swp_entry_t entry, struct page *page)
980{
981 struct list_head *p, *next;
982 struct shmem_inode_info *info;
983 int found = 0;
984
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800985 mutex_lock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 list_for_each_safe(p, next, &shmem_swaplist) {
987 info = list_entry(p, struct shmem_inode_info, swaplist);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800988 found = shmem_unuse_inode(info, entry, page);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800989 cond_resched();
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800990 if (found)
991 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 }
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800993 mutex_unlock(&shmem_swaplist_mutex);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800994out: return found; /* 0 or 1 or -ENOMEM */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995}
996
997/*
998 * Move the page from the page cache to the swap cache.
999 */
1000static int shmem_writepage(struct page *page, struct writeback_control *wbc)
1001{
1002 struct shmem_inode_info *info;
1003 swp_entry_t *entry, swap;
1004 struct address_space *mapping;
1005 unsigned long index;
1006 struct inode *inode;
1007
1008 BUG_ON(!PageLocked(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 mapping = page->mapping;
1010 index = page->index;
1011 inode = mapping->host;
1012 info = SHMEM_I(inode);
1013 if (info->flags & VM_LOCKED)
1014 goto redirty;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001015 if (!total_swap_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 goto redirty;
1017
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001018 /*
1019 * shmem_backing_dev_info's capabilities prevent regular writeback or
1020 * sync from ever calling shmem_writepage; but a stacking filesystem
1021 * may use the ->writepage of its underlying filesystem, in which case
1022 * tmpfs should write out to swap only in response to memory pressure,
1023 * and not for pdflush or sync. However, in those cases, we do still
1024 * want to check if there's a redundant swappage to be discarded.
1025 */
1026 if (wbc->for_reclaim)
1027 swap = get_swap_page();
1028 else
1029 swap.val = 0;
1030
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 spin_lock(&info->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032 if (index >= info->next_index) {
1033 BUG_ON(!(info->flags & SHMEM_TRUNCATE));
1034 goto unlock;
1035 }
1036 entry = shmem_swp_entry(info, index, NULL);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001037 if (entry->val) {
1038 /*
1039 * The more uptodate page coming down from a stacked
1040 * writepage should replace our old swappage.
1041 */
1042 free_swap_and_cache(*entry);
1043 shmem_swp_set(info, entry, 0);
1044 }
1045 shmem_recalc_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001047 if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
Hugh Dickins73b12622008-02-04 22:28:50 -08001048 remove_from_page_cache(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 shmem_swp_set(info, entry, swap.val);
1050 shmem_swp_unmap(entry);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -08001051 if (list_empty(&info->swaplist))
1052 inode = igrab(inode);
1053 else
1054 inode = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 spin_unlock(&info->lock);
Hugh Dickins73b12622008-02-04 22:28:50 -08001056 swap_duplicate(swap);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001057 BUG_ON(page_mapped(page));
Hugh Dickins73b12622008-02-04 22:28:50 -08001058 page_cache_release(page); /* pagecache ref */
1059 set_page_dirty(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 unlock_page(page);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -08001061 if (inode) {
1062 mutex_lock(&shmem_swaplist_mutex);
1063 /* move instead of add in case we're racing */
1064 list_move_tail(&info->swaplist, &shmem_swaplist);
1065 mutex_unlock(&shmem_swaplist_mutex);
1066 iput(inode);
1067 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 return 0;
1069 }
1070
1071 shmem_swp_unmap(entry);
1072unlock:
1073 spin_unlock(&info->lock);
1074 swap_free(swap);
1075redirty:
1076 set_page_dirty(page);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001077 if (wbc->for_reclaim)
1078 return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */
1079 unlock_page(page);
1080 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081}
1082
1083#ifdef CONFIG_NUMA
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001084#ifdef CONFIG_TMPFS
1085static int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001086{
1087 char *nodelist = strchr(value, ':');
1088 int err = 1;
1089
1090 if (nodelist) {
1091 /* NUL-terminate policy string */
1092 *nodelist++ = '\0';
1093 if (nodelist_parse(nodelist, *policy_nodes))
1094 goto out;
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07001095 if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY]))
Hugh Dickinsa2109062007-06-08 13:46:46 -07001096 goto out;
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001097 }
1098 if (!strcmp(value, "default")) {
1099 *policy = MPOL_DEFAULT;
1100 /* Don't allow a nodelist */
1101 if (!nodelist)
1102 err = 0;
1103 } else if (!strcmp(value, "prefer")) {
1104 *policy = MPOL_PREFERRED;
1105 /* Insist on a nodelist of one node only */
1106 if (nodelist) {
1107 char *rest = nodelist;
1108 while (isdigit(*rest))
1109 rest++;
1110 if (!*rest)
1111 err = 0;
1112 }
1113 } else if (!strcmp(value, "bind")) {
1114 *policy = MPOL_BIND;
1115 /* Insist on a nodelist */
1116 if (nodelist)
1117 err = 0;
1118 } else if (!strcmp(value, "interleave")) {
1119 *policy = MPOL_INTERLEAVE;
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07001120 /*
1121 * Default to online nodes with memory if no nodelist
1122 */
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001123 if (!nodelist)
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07001124 *policy_nodes = node_states[N_HIGH_MEMORY];
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001125 err = 0;
1126 }
1127out:
1128 /* Restore string for error message */
1129 if (nodelist)
1130 *--nodelist = ':';
1131 return err;
1132}
1133
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001134static void shmem_show_mpol(struct seq_file *seq, int policy,
1135 const nodemask_t policy_nodes)
1136{
1137 char *policy_string;
1138
1139 switch (policy) {
1140 case MPOL_PREFERRED:
1141 policy_string = "prefer";
1142 break;
1143 case MPOL_BIND:
1144 policy_string = "bind";
1145 break;
1146 case MPOL_INTERLEAVE:
1147 policy_string = "interleave";
1148 break;
1149 default:
1150 /* MPOL_DEFAULT */
1151 return;
1152 }
1153
1154 seq_printf(seq, ",mpol=%s", policy_string);
1155
1156 if (policy != MPOL_INTERLEAVE ||
1157 !nodes_equal(policy_nodes, node_states[N_HIGH_MEMORY])) {
1158 char buffer[64];
1159 int len;
1160
1161 len = nodelist_scnprintf(buffer, sizeof(buffer), policy_nodes);
1162 if (len < sizeof(buffer))
1163 seq_printf(seq, ":%s", buffer);
1164 else
1165 seq_printf(seq, ":?");
1166 }
1167}
1168#endif /* CONFIG_TMPFS */
1169
Hugh Dickins02098fe2008-02-04 22:28:42 -08001170static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
1171 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 struct vm_area_struct pvma;
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001174 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175
1176 /* Create a pseudo vma that just contains the policy */
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001177 pvma.vm_start = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 pvma.vm_pgoff = idx;
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001179 pvma.vm_ops = NULL;
1180 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
Hugh Dickins02098fe2008-02-04 22:28:42 -08001181 page = swapin_readahead(entry, gfp, &pvma, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 mpol_free(pvma.vm_policy);
1183 return page;
1184}
1185
Hugh Dickins02098fe2008-02-04 22:28:42 -08001186static struct page *shmem_alloc_page(gfp_t gfp,
1187 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188{
1189 struct vm_area_struct pvma;
1190 struct page *page;
1191
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001192 /* Create a pseudo vma that just contains the policy */
1193 pvma.vm_start = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 pvma.vm_pgoff = idx;
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001195 pvma.vm_ops = NULL;
1196 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001197 page = alloc_page_vma(gfp, &pvma, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 mpol_free(pvma.vm_policy);
1199 return page;
1200}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001201#else /* !CONFIG_NUMA */
1202#ifdef CONFIG_TMPFS
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07001203static inline int shmem_parse_mpol(char *value, int *policy,
1204 nodemask_t *policy_nodes)
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001205{
1206 return 1;
1207}
1208
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001209static inline void shmem_show_mpol(struct seq_file *seq, int policy,
1210 const nodemask_t policy_nodes)
1211{
1212}
1213#endif /* CONFIG_TMPFS */
1214
Hugh Dickins02098fe2008-02-04 22:28:42 -08001215static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
1216 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217{
Hugh Dickins02098fe2008-02-04 22:28:42 -08001218 return swapin_readahead(entry, gfp, NULL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219}
1220
Hugh Dickins02098fe2008-02-04 22:28:42 -08001221static inline struct page *shmem_alloc_page(gfp_t gfp,
1222 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223{
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001224 return alloc_page(gfp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001226#endif /* CONFIG_NUMA */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227
1228/*
1229 * shmem_getpage - either get the page from swap or allocate a new one
1230 *
1231 * If we allocate a new one we do not mark it dirty. That's up to the
1232 * vm. If we swap it in we mark it dirty since we also free the swap
1233 * entry since a page cannot live in both the swap and page cache
1234 */
1235static int shmem_getpage(struct inode *inode, unsigned long idx,
1236 struct page **pagep, enum sgp_type sgp, int *type)
1237{
1238 struct address_space *mapping = inode->i_mapping;
1239 struct shmem_inode_info *info = SHMEM_I(inode);
1240 struct shmem_sb_info *sbinfo;
1241 struct page *filepage = *pagep;
1242 struct page *swappage;
1243 swp_entry_t *entry;
1244 swp_entry_t swap;
Hugh Dickins02098fe2008-02-04 22:28:42 -08001245 gfp_t gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 int error;
1247
1248 if (idx >= SHMEM_MAX_INDEX)
1249 return -EFBIG;
Nick Piggin54cb8822007-07-19 01:46:59 -07001250
1251 if (type)
Nick Piggin83c54072007-07-19 01:47:05 -07001252 *type = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07001253
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 /*
1255 * Normally, filepage is NULL on entry, and either found
1256 * uptodate immediately, or allocated and zeroed, or read
1257 * in under swappage, which is then assigned to filepage.
Hugh Dickins5402b972008-02-04 22:28:44 -08001258 * But shmem_readpage (required for splice) passes in a locked
Hugh Dickinsae976412007-06-04 10:00:39 +02001259 * filepage, which may be found not uptodate by other callers
1260 * too, and may need to be copied from the swappage read in.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 */
1262repeat:
1263 if (!filepage)
1264 filepage = find_lock_page(mapping, idx);
1265 if (filepage && PageUptodate(filepage))
1266 goto done;
1267 error = 0;
Hugh Dickins02098fe2008-02-04 22:28:42 -08001268 gfp = mapping_gfp_mask(mapping);
Hugh Dickinsb409f9f2008-02-04 22:28:54 -08001269 if (!filepage) {
1270 /*
1271 * Try to preload while we can wait, to not make a habit of
1272 * draining atomic reserves; but don't latch on to this cpu.
1273 */
1274 error = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
1275 if (error)
1276 goto failed;
1277 radix_tree_preload_end();
1278 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279
1280 spin_lock(&info->lock);
1281 shmem_recalc_inode(inode);
1282 entry = shmem_swp_alloc(info, idx, sgp);
1283 if (IS_ERR(entry)) {
1284 spin_unlock(&info->lock);
1285 error = PTR_ERR(entry);
1286 goto failed;
1287 }
1288 swap = *entry;
1289
1290 if (swap.val) {
1291 /* Look it up and read it in.. */
1292 swappage = lookup_swap_cache(swap);
1293 if (!swappage) {
1294 shmem_swp_unmap(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001295 /* here we actually do the io */
Nick Piggin83c54072007-07-19 01:47:05 -07001296 if (type && !(*type & VM_FAULT_MAJOR)) {
Christoph Lameterf8891e52006-06-30 01:55:45 -07001297 __count_vm_event(PGMAJFAULT);
Nick Piggin83c54072007-07-19 01:47:05 -07001298 *type |= VM_FAULT_MAJOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299 }
Christoph Lameterf8891e52006-06-30 01:55:45 -07001300 spin_unlock(&info->lock);
Hugh Dickins02098fe2008-02-04 22:28:42 -08001301 swappage = shmem_swapin(swap, gfp, info, idx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 if (!swappage) {
1303 spin_lock(&info->lock);
1304 entry = shmem_swp_alloc(info, idx, sgp);
1305 if (IS_ERR(entry))
1306 error = PTR_ERR(entry);
1307 else {
1308 if (entry->val == swap.val)
1309 error = -ENOMEM;
1310 shmem_swp_unmap(entry);
1311 }
1312 spin_unlock(&info->lock);
1313 if (error)
1314 goto failed;
1315 goto repeat;
1316 }
1317 wait_on_page_locked(swappage);
1318 page_cache_release(swappage);
1319 goto repeat;
1320 }
1321
1322 /* We have to do this with page locked to prevent races */
1323 if (TestSetPageLocked(swappage)) {
1324 shmem_swp_unmap(entry);
1325 spin_unlock(&info->lock);
1326 wait_on_page_locked(swappage);
1327 page_cache_release(swappage);
1328 goto repeat;
1329 }
1330 if (PageWriteback(swappage)) {
1331 shmem_swp_unmap(entry);
1332 spin_unlock(&info->lock);
1333 wait_on_page_writeback(swappage);
1334 unlock_page(swappage);
1335 page_cache_release(swappage);
1336 goto repeat;
1337 }
1338 if (!PageUptodate(swappage)) {
1339 shmem_swp_unmap(entry);
1340 spin_unlock(&info->lock);
1341 unlock_page(swappage);
1342 page_cache_release(swappage);
1343 error = -EIO;
1344 goto failed;
1345 }
1346
1347 if (filepage) {
1348 shmem_swp_set(info, entry, 0);
1349 shmem_swp_unmap(entry);
1350 delete_from_swap_cache(swappage);
1351 spin_unlock(&info->lock);
1352 copy_highpage(filepage, swappage);
1353 unlock_page(swappage);
1354 page_cache_release(swappage);
1355 flush_dcache_page(filepage);
1356 SetPageUptodate(filepage);
1357 set_page_dirty(filepage);
1358 swap_free(swap);
Hugh Dickins73b12622008-02-04 22:28:50 -08001359 } else if (!(error = add_to_page_cache(
Hugh Dickinsb409f9f2008-02-04 22:28:54 -08001360 swappage, mapping, idx, GFP_NOWAIT))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 info->flags |= SHMEM_PAGEIN;
1362 shmem_swp_set(info, entry, 0);
1363 shmem_swp_unmap(entry);
Hugh Dickins73b12622008-02-04 22:28:50 -08001364 delete_from_swap_cache(swappage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 spin_unlock(&info->lock);
1366 filepage = swappage;
Hugh Dickins73b12622008-02-04 22:28:50 -08001367 set_page_dirty(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 swap_free(swap);
1369 } else {
1370 shmem_swp_unmap(entry);
1371 spin_unlock(&info->lock);
1372 unlock_page(swappage);
1373 page_cache_release(swappage);
Hugh Dickins82369552008-02-07 00:14:22 -08001374 if (error == -ENOMEM) {
1375 /* allow reclaim from this memory cgroup */
1376 error = mem_cgroup_cache_charge(NULL,
1377 current->mm, gfp & ~__GFP_HIGHMEM);
1378 if (error)
1379 goto failed;
1380 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 goto repeat;
1382 }
1383 } else if (sgp == SGP_READ && !filepage) {
1384 shmem_swp_unmap(entry);
1385 filepage = find_get_page(mapping, idx);
1386 if (filepage &&
1387 (!PageUptodate(filepage) || TestSetPageLocked(filepage))) {
1388 spin_unlock(&info->lock);
1389 wait_on_page_locked(filepage);
1390 page_cache_release(filepage);
1391 filepage = NULL;
1392 goto repeat;
1393 }
1394 spin_unlock(&info->lock);
1395 } else {
1396 shmem_swp_unmap(entry);
1397 sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001398 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 spin_lock(&sbinfo->stat_lock);
1400 if (sbinfo->free_blocks == 0 ||
1401 shmem_acct_block(info->flags)) {
1402 spin_unlock(&sbinfo->stat_lock);
1403 spin_unlock(&info->lock);
1404 error = -ENOSPC;
1405 goto failed;
1406 }
1407 sbinfo->free_blocks--;
1408 inode->i_blocks += BLOCKS_PER_PAGE;
1409 spin_unlock(&sbinfo->stat_lock);
1410 } else if (shmem_acct_block(info->flags)) {
1411 spin_unlock(&info->lock);
1412 error = -ENOSPC;
1413 goto failed;
1414 }
1415
1416 if (!filepage) {
1417 spin_unlock(&info->lock);
Hugh Dickins02098fe2008-02-04 22:28:42 -08001418 filepage = shmem_alloc_page(gfp, info, idx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 if (!filepage) {
1420 shmem_unacct_blocks(info->flags, 1);
1421 shmem_free_blocks(inode, 1);
1422 error = -ENOMEM;
1423 goto failed;
1424 }
1425
Hugh Dickins82369552008-02-07 00:14:22 -08001426 /* Precharge page while we can wait, compensate after */
1427 error = mem_cgroup_cache_charge(filepage, current->mm,
1428 gfp & ~__GFP_HIGHMEM);
1429 if (error) {
1430 page_cache_release(filepage);
1431 shmem_unacct_blocks(info->flags, 1);
1432 shmem_free_blocks(inode, 1);
1433 filepage = NULL;
1434 goto failed;
1435 }
1436
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437 spin_lock(&info->lock);
1438 entry = shmem_swp_alloc(info, idx, sgp);
1439 if (IS_ERR(entry))
1440 error = PTR_ERR(entry);
1441 else {
1442 swap = *entry;
1443 shmem_swp_unmap(entry);
1444 }
1445 if (error || swap.val || 0 != add_to_page_cache_lru(
Hugh Dickinsb409f9f2008-02-04 22:28:54 -08001446 filepage, mapping, idx, GFP_NOWAIT)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 spin_unlock(&info->lock);
Hugh Dickins82369552008-02-07 00:14:22 -08001448 mem_cgroup_uncharge_page(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 page_cache_release(filepage);
1450 shmem_unacct_blocks(info->flags, 1);
1451 shmem_free_blocks(inode, 1);
1452 filepage = NULL;
1453 if (error)
1454 goto failed;
1455 goto repeat;
1456 }
Hugh Dickins82369552008-02-07 00:14:22 -08001457 mem_cgroup_uncharge_page(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458 info->flags |= SHMEM_PAGEIN;
1459 }
1460
1461 info->alloced++;
1462 spin_unlock(&info->lock);
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001463 clear_highpage(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 flush_dcache_page(filepage);
1465 SetPageUptodate(filepage);
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001466 if (sgp == SGP_DIRTY)
1467 set_page_dirty(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 }
1469done:
Hugh Dickinsd3602442008-02-04 22:28:44 -08001470 *pagep = filepage;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 return 0;
1472
1473failed:
1474 if (*pagep != filepage) {
1475 unlock_page(filepage);
1476 page_cache_release(filepage);
1477 }
1478 return error;
1479}
1480
Nick Piggind0217ac2007-07-19 01:47:03 -07001481static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001483 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 int error;
Nick Piggind0217ac2007-07-19 01:47:03 -07001485 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486
Nick Piggind0217ac2007-07-19 01:47:03 -07001487 if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
1488 return VM_FAULT_SIGBUS;
Nick Piggind00806b2007-07-19 01:46:57 -07001489
Hugh Dickins27d54b32008-02-04 22:28:43 -08001490 error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
Nick Piggind0217ac2007-07-19 01:47:03 -07001491 if (error)
1492 return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493
Nick Piggind0217ac2007-07-19 01:47:03 -07001494 mark_page_accessed(vmf->page);
Nick Piggin83c54072007-07-19 01:47:05 -07001495 return ret | VM_FAULT_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496}
1497
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498#ifdef CONFIG_NUMA
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001499static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001501 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502 return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
1503}
1504
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001505static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
1506 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001508 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509 unsigned long idx;
1510
1511 idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
1512 return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
1513}
1514#endif
1515
1516int shmem_lock(struct file *file, int lock, struct user_struct *user)
1517{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001518 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 struct shmem_inode_info *info = SHMEM_I(inode);
1520 int retval = -ENOMEM;
1521
1522 spin_lock(&info->lock);
1523 if (lock && !(info->flags & VM_LOCKED)) {
1524 if (!user_shm_lock(inode->i_size, user))
1525 goto out_nomem;
1526 info->flags |= VM_LOCKED;
1527 }
1528 if (!lock && (info->flags & VM_LOCKED) && user) {
1529 user_shm_unlock(inode->i_size, user);
1530 info->flags &= ~VM_LOCKED;
1531 }
1532 retval = 0;
1533out_nomem:
1534 spin_unlock(&info->lock);
1535 return retval;
1536}
1537
Adrian Bunk9b83a6a2007-02-28 20:11:03 -08001538static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539{
1540 file_accessed(file);
1541 vma->vm_ops = &shmem_vm_ops;
Nick Piggind0217ac2007-07-19 01:47:03 -07001542 vma->vm_flags |= VM_CAN_NONLINEAR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 return 0;
1544}
1545
1546static struct inode *
1547shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
1548{
1549 struct inode *inode;
1550 struct shmem_inode_info *info;
1551 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
1552
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001553 if (shmem_reserve_inode(sb))
1554 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555
1556 inode = new_inode(sb);
1557 if (inode) {
1558 inode->i_mode = mode;
1559 inode->i_uid = current->fsuid;
1560 inode->i_gid = current->fsgid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561 inode->i_blocks = 0;
1562 inode->i_mapping->a_ops = &shmem_aops;
1563 inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
1564 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
David M. Grimes91828a42006-10-17 00:09:45 -07001565 inode->i_generation = get_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 info = SHMEM_I(inode);
1567 memset(info, 0, (char *)inode - (char *)info);
1568 spin_lock_init(&info->lock);
1569 INIT_LIST_HEAD(&info->swaplist);
1570
1571 switch (mode & S_IFMT) {
1572 default:
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001573 inode->i_op = &shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 init_special_inode(inode, mode, dev);
1575 break;
1576 case S_IFREG:
1577 inode->i_op = &shmem_inode_operations;
1578 inode->i_fop = &shmem_file_operations;
Robin Holt7339ff82006-01-14 13:20:48 -08001579 mpol_shared_policy_init(&info->policy, sbinfo->policy,
1580 &sbinfo->policy_nodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001581 break;
1582 case S_IFDIR:
Dave Hansend8c76e62006-09-30 23:29:04 -07001583 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001584 /* Some things misbehave if size == 0 on a directory */
1585 inode->i_size = 2 * BOGO_DIRENT_SIZE;
1586 inode->i_op = &shmem_dir_inode_operations;
1587 inode->i_fop = &simple_dir_operations;
1588 break;
1589 case S_IFLNK:
1590 /*
1591 * Must not load anything in the rbtree,
1592 * mpol_free_shared_policy will not be called.
1593 */
Robin Holt7339ff82006-01-14 13:20:48 -08001594 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT,
1595 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596 break;
1597 }
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001598 } else
1599 shmem_free_inode(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600 return inode;
1601}
1602
1603#ifdef CONFIG_TMPFS
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001604static const struct inode_operations shmem_symlink_inode_operations;
1605static const struct inode_operations shmem_symlink_inline_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606
1607/*
Nick Piggin800d15a2007-10-16 01:25:03 -07001608 * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin;
Hugh Dickinsae976412007-06-04 10:00:39 +02001609 * but providing them allows a tmpfs file to be used for splice, sendfile, and
1610 * below the loop driver, in the generic fashion that many filesystems support.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611 */
Hugh Dickinsae976412007-06-04 10:00:39 +02001612static int shmem_readpage(struct file *file, struct page *page)
1613{
1614 struct inode *inode = page->mapping->host;
1615 int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL);
1616 unlock_page(page);
1617 return error;
1618}
1619
Linus Torvalds1da177e2005-04-16 15:20:36 -07001620static int
Nick Piggin800d15a2007-10-16 01:25:03 -07001621shmem_write_begin(struct file *file, struct address_space *mapping,
1622 loff_t pos, unsigned len, unsigned flags,
1623 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624{
Nick Piggin800d15a2007-10-16 01:25:03 -07001625 struct inode *inode = mapping->host;
1626 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1627 *pagep = NULL;
1628 return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL);
1629}
1630
1631static int
1632shmem_write_end(struct file *file, struct address_space *mapping,
1633 loff_t pos, unsigned len, unsigned copied,
1634 struct page *page, void *fsdata)
1635{
1636 struct inode *inode = mapping->host;
1637
Hugh Dickinsd3602442008-02-04 22:28:44 -08001638 if (pos + copied > inode->i_size)
1639 i_size_write(inode, pos + copied);
1640
1641 unlock_page(page);
Nick Piggin800d15a2007-10-16 01:25:03 -07001642 set_page_dirty(page);
1643 page_cache_release(page);
1644
Nick Piggin800d15a2007-10-16 01:25:03 -07001645 return copied;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646}
1647
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
1649{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001650 struct inode *inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001651 struct address_space *mapping = inode->i_mapping;
1652 unsigned long index, offset;
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001653 enum sgp_type sgp = SGP_READ;
1654
1655 /*
1656 * Might this read be for a stacking filesystem? Then when reading
1657 * holes of a sparse file, we actually need to allocate those pages,
1658 * and even mark them dirty, so it cannot exceed the max_blocks limit.
1659 */
1660 if (segment_eq(get_fs(), KERNEL_DS))
1661 sgp = SGP_DIRTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662
1663 index = *ppos >> PAGE_CACHE_SHIFT;
1664 offset = *ppos & ~PAGE_CACHE_MASK;
1665
1666 for (;;) {
1667 struct page *page = NULL;
1668 unsigned long end_index, nr, ret;
1669 loff_t i_size = i_size_read(inode);
1670
1671 end_index = i_size >> PAGE_CACHE_SHIFT;
1672 if (index > end_index)
1673 break;
1674 if (index == end_index) {
1675 nr = i_size & ~PAGE_CACHE_MASK;
1676 if (nr <= offset)
1677 break;
1678 }
1679
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001680 desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681 if (desc->error) {
1682 if (desc->error == -EINVAL)
1683 desc->error = 0;
1684 break;
1685 }
Hugh Dickinsd3602442008-02-04 22:28:44 -08001686 if (page)
1687 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688
1689 /*
1690 * We must evaluate after, since reads (unlike writes)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001691 * are called without i_mutex protection against truncate
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692 */
1693 nr = PAGE_CACHE_SIZE;
1694 i_size = i_size_read(inode);
1695 end_index = i_size >> PAGE_CACHE_SHIFT;
1696 if (index == end_index) {
1697 nr = i_size & ~PAGE_CACHE_MASK;
1698 if (nr <= offset) {
1699 if (page)
1700 page_cache_release(page);
1701 break;
1702 }
1703 }
1704 nr -= offset;
1705
1706 if (page) {
1707 /*
1708 * If users can be writing to this page using arbitrary
1709 * virtual addresses, take care about potential aliasing
1710 * before reading the page on the kernel side.
1711 */
1712 if (mapping_writably_mapped(mapping))
1713 flush_dcache_page(page);
1714 /*
1715 * Mark the page accessed if we read the beginning.
1716 */
1717 if (!offset)
1718 mark_page_accessed(page);
Nick Pigginb5810032005-10-29 18:16:12 -07001719 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001720 page = ZERO_PAGE(0);
Nick Pigginb5810032005-10-29 18:16:12 -07001721 page_cache_get(page);
1722 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723
1724 /*
1725 * Ok, we have the page, and it's up-to-date, so
1726 * now we can copy it to user space...
1727 *
1728 * The actor routine returns how many bytes were actually used..
1729 * NOTE! This may not be the same as how much of a user buffer
1730 * we filled up (we may be padding etc), so we can only update
1731 * "pos" here (the actor routine has to update the user buffer
1732 * pointers and the remaining count).
1733 */
1734 ret = actor(desc, page, offset, nr);
1735 offset += ret;
1736 index += offset >> PAGE_CACHE_SHIFT;
1737 offset &= ~PAGE_CACHE_MASK;
1738
1739 page_cache_release(page);
1740 if (ret != nr || !desc->count)
1741 break;
1742
1743 cond_resched();
1744 }
1745
1746 *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
1747 file_accessed(filp);
1748}
1749
1750static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
1751{
1752 read_descriptor_t desc;
1753
1754 if ((ssize_t) count < 0)
1755 return -EINVAL;
1756 if (!access_ok(VERIFY_WRITE, buf, count))
1757 return -EFAULT;
1758 if (!count)
1759 return 0;
1760
1761 desc.written = 0;
1762 desc.count = count;
1763 desc.arg.buf = buf;
1764 desc.error = 0;
1765
1766 do_shmem_file_read(filp, ppos, &desc, file_read_actor);
1767 if (desc.written)
1768 return desc.written;
1769 return desc.error;
1770}
1771
David Howells726c3342006-06-23 02:02:58 -07001772static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773{
David Howells726c3342006-06-23 02:02:58 -07001774 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775
1776 buf->f_type = TMPFS_MAGIC;
1777 buf->f_bsize = PAGE_CACHE_SIZE;
1778 buf->f_namelen = NAME_MAX;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001779 spin_lock(&sbinfo->stat_lock);
1780 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 buf->f_blocks = sbinfo->max_blocks;
1782 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001783 }
1784 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785 buf->f_files = sbinfo->max_inodes;
1786 buf->f_ffree = sbinfo->free_inodes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787 }
1788 /* else leave those fields 0 like simple_statfs */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001789 spin_unlock(&sbinfo->stat_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 return 0;
1791}
1792
1793/*
1794 * File creation. Allocate an inode, and we're done..
1795 */
1796static int
1797shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1798{
1799 struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev);
1800 int error = -ENOSPC;
1801
1802 if (inode) {
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001803 error = security_inode_init_security(inode, dir, NULL, NULL,
1804 NULL);
1805 if (error) {
1806 if (error != -EOPNOTSUPP) {
1807 iput(inode);
1808 return error;
1809 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001810 }
1811 error = shmem_acl_init(inode, dir);
1812 if (error) {
1813 iput(inode);
1814 return error;
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001815 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001816 if (dir->i_mode & S_ISGID) {
1817 inode->i_gid = dir->i_gid;
1818 if (S_ISDIR(mode))
1819 inode->i_mode |= S_ISGID;
1820 }
1821 dir->i_size += BOGO_DIRENT_SIZE;
1822 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1823 d_instantiate(dentry, inode);
1824 dget(dentry); /* Extra count - pin the dentry in core */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001825 }
1826 return error;
1827}
1828
1829static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1830{
1831 int error;
1832
1833 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
1834 return error;
Dave Hansend8c76e62006-09-30 23:29:04 -07001835 inc_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836 return 0;
1837}
1838
1839static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
1840 struct nameidata *nd)
1841{
1842 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
1843}
1844
1845/*
1846 * Link a file..
1847 */
1848static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1849{
1850 struct inode *inode = old_dentry->d_inode;
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001851 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001852
1853 /*
1854 * No ordinary (disk based) filesystem counts links as inodes;
1855 * but each new link needs a new dentry, pinning lowmem, and
1856 * tmpfs dentries cannot be pruned until they are unlinked.
1857 */
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001858 ret = shmem_reserve_inode(inode->i_sb);
1859 if (ret)
1860 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861
1862 dir->i_size += BOGO_DIRENT_SIZE;
1863 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -07001864 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 atomic_inc(&inode->i_count); /* New dentry reference */
1866 dget(dentry); /* Extra pinning count for the created dentry */
1867 d_instantiate(dentry, inode);
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001868out:
1869 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870}
1871
1872static int shmem_unlink(struct inode *dir, struct dentry *dentry)
1873{
1874 struct inode *inode = dentry->d_inode;
1875
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001876 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
1877 shmem_free_inode(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878
1879 dir->i_size -= BOGO_DIRENT_SIZE;
1880 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001881 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882 dput(dentry); /* Undo the count from "create" - this does all the work */
1883 return 0;
1884}
1885
1886static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
1887{
1888 if (!simple_empty(dentry))
1889 return -ENOTEMPTY;
1890
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001891 drop_nlink(dentry->d_inode);
1892 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 return shmem_unlink(dir, dentry);
1894}
1895
1896/*
1897 * The VFS layer already does all the dentry stuff for rename,
1898 * we just have to decrement the usage count for the target if
1899 * it exists so that the VFS layer correctly free's it when it
1900 * gets overwritten.
1901 */
1902static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
1903{
1904 struct inode *inode = old_dentry->d_inode;
1905 int they_are_dirs = S_ISDIR(inode->i_mode);
1906
1907 if (!simple_empty(new_dentry))
1908 return -ENOTEMPTY;
1909
1910 if (new_dentry->d_inode) {
1911 (void) shmem_unlink(new_dir, new_dentry);
1912 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001913 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001915 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -07001916 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917 }
1918
1919 old_dir->i_size -= BOGO_DIRENT_SIZE;
1920 new_dir->i_size += BOGO_DIRENT_SIZE;
1921 old_dir->i_ctime = old_dir->i_mtime =
1922 new_dir->i_ctime = new_dir->i_mtime =
1923 inode->i_ctime = CURRENT_TIME;
1924 return 0;
1925}
1926
1927static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1928{
1929 int error;
1930 int len;
1931 struct inode *inode;
1932 struct page *page = NULL;
1933 char *kaddr;
1934 struct shmem_inode_info *info;
1935
1936 len = strlen(symname) + 1;
1937 if (len > PAGE_CACHE_SIZE)
1938 return -ENAMETOOLONG;
1939
1940 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
1941 if (!inode)
1942 return -ENOSPC;
1943
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001944 error = security_inode_init_security(inode, dir, NULL, NULL,
1945 NULL);
1946 if (error) {
1947 if (error != -EOPNOTSUPP) {
1948 iput(inode);
1949 return error;
1950 }
1951 error = 0;
1952 }
1953
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954 info = SHMEM_I(inode);
1955 inode->i_size = len-1;
1956 if (len <= (char *)inode - (char *)info) {
1957 /* do it inline */
1958 memcpy(info, symname, len);
1959 inode->i_op = &shmem_symlink_inline_operations;
1960 } else {
1961 error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
1962 if (error) {
1963 iput(inode);
1964 return error;
1965 }
Hugh Dickinsd3602442008-02-04 22:28:44 -08001966 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 inode->i_op = &shmem_symlink_inode_operations;
1968 kaddr = kmap_atomic(page, KM_USER0);
1969 memcpy(kaddr, symname, len);
1970 kunmap_atomic(kaddr, KM_USER0);
1971 set_page_dirty(page);
1972 page_cache_release(page);
1973 }
1974 if (dir->i_mode & S_ISGID)
1975 inode->i_gid = dir->i_gid;
1976 dir->i_size += BOGO_DIRENT_SIZE;
1977 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1978 d_instantiate(dentry, inode);
1979 dget(dentry);
1980 return 0;
1981}
1982
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001983static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984{
1985 nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001986 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987}
1988
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001989static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990{
1991 struct page *page = NULL;
1992 int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
1993 nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
Hugh Dickinsd3602442008-02-04 22:28:44 -08001994 if (page)
1995 unlock_page(page);
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001996 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001997}
1998
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001999static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000{
2001 if (!IS_ERR(nd_get_link(nd))) {
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002002 struct page *page = cookie;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 kunmap(page);
2004 mark_page_accessed(page);
2005 page_cache_release(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002006 }
2007}
2008
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002009static const struct inode_operations shmem_symlink_inline_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002010 .readlink = generic_readlink,
2011 .follow_link = shmem_follow_link_inline,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002012};
2013
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002014static const struct inode_operations shmem_symlink_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002015 .truncate = shmem_truncate,
2016 .readlink = generic_readlink,
2017 .follow_link = shmem_follow_link,
2018 .put_link = shmem_put_link,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002019};
2020
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002021#ifdef CONFIG_TMPFS_POSIX_ACL
2022/**
2023 * Superblocks without xattr inode operations will get security.* xattr
2024 * support from the VFS "for free". As soon as we have any other xattrs
2025 * like ACLs, we also need to implement the security.* handlers at
2026 * filesystem level, though.
2027 */
2028
2029static size_t shmem_xattr_security_list(struct inode *inode, char *list,
2030 size_t list_len, const char *name,
2031 size_t name_len)
2032{
2033 return security_inode_listsecurity(inode, list, list_len);
2034}
2035
2036static int shmem_xattr_security_get(struct inode *inode, const char *name,
2037 void *buffer, size_t size)
2038{
2039 if (strcmp(name, "") == 0)
2040 return -EINVAL;
David P. Quigley42492592008-02-04 22:29:39 -08002041 return xattr_getsecurity(inode, name, buffer, size);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002042}
2043
2044static int shmem_xattr_security_set(struct inode *inode, const char *name,
2045 const void *value, size_t size, int flags)
2046{
2047 if (strcmp(name, "") == 0)
2048 return -EINVAL;
2049 return security_inode_setsecurity(inode, name, value, size, flags);
2050}
2051
Adrian Bunk1f370a22006-12-06 20:38:21 -08002052static struct xattr_handler shmem_xattr_security_handler = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002053 .prefix = XATTR_SECURITY_PREFIX,
2054 .list = shmem_xattr_security_list,
2055 .get = shmem_xattr_security_get,
2056 .set = shmem_xattr_security_set,
2057};
2058
2059static struct xattr_handler *shmem_xattr_handlers[] = {
2060 &shmem_xattr_acl_access_handler,
2061 &shmem_xattr_acl_default_handler,
2062 &shmem_xattr_security_handler,
2063 NULL
2064};
2065#endif
2066
David M. Grimes91828a42006-10-17 00:09:45 -07002067static struct dentry *shmem_get_parent(struct dentry *child)
2068{
2069 return ERR_PTR(-ESTALE);
2070}
2071
2072static int shmem_match(struct inode *ino, void *vfh)
2073{
2074 __u32 *fh = vfh;
2075 __u64 inum = fh[2];
2076 inum = (inum << 32) | fh[1];
2077 return ino->i_ino == inum && fh[0] == ino->i_generation;
2078}
2079
Christoph Hellwig480b1162007-10-21 16:42:13 -07002080static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
2081 struct fid *fid, int fh_len, int fh_type)
David M. Grimes91828a42006-10-17 00:09:45 -07002082{
David M. Grimes91828a42006-10-17 00:09:45 -07002083 struct inode *inode;
Christoph Hellwig480b1162007-10-21 16:42:13 -07002084 struct dentry *dentry = NULL;
2085 u64 inum = fid->raw[2];
2086 inum = (inum << 32) | fid->raw[1];
David M. Grimes91828a42006-10-17 00:09:45 -07002087
Christoph Hellwig480b1162007-10-21 16:42:13 -07002088 if (fh_len < 3)
2089 return NULL;
2090
2091 inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
2092 shmem_match, fid->raw);
David M. Grimes91828a42006-10-17 00:09:45 -07002093 if (inode) {
Christoph Hellwig480b1162007-10-21 16:42:13 -07002094 dentry = d_find_alias(inode);
David M. Grimes91828a42006-10-17 00:09:45 -07002095 iput(inode);
2096 }
2097
Christoph Hellwig480b1162007-10-21 16:42:13 -07002098 return dentry;
David M. Grimes91828a42006-10-17 00:09:45 -07002099}
2100
2101static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
2102 int connectable)
2103{
2104 struct inode *inode = dentry->d_inode;
2105
2106 if (*len < 3)
2107 return 255;
2108
2109 if (hlist_unhashed(&inode->i_hash)) {
2110 /* Unfortunately insert_inode_hash is not idempotent,
2111 * so as we hash inodes here rather than at creation
2112 * time, we need a lock to ensure we only try
2113 * to do it once
2114 */
2115 static DEFINE_SPINLOCK(lock);
2116 spin_lock(&lock);
2117 if (hlist_unhashed(&inode->i_hash))
2118 __insert_inode_hash(inode,
2119 inode->i_ino + inode->i_generation);
2120 spin_unlock(&lock);
2121 }
2122
2123 fh[0] = inode->i_generation;
2124 fh[1] = inode->i_ino;
2125 fh[2] = ((__u64)inode->i_ino) >> 32;
2126
2127 *len = 3;
2128 return 1;
2129}
2130
Christoph Hellwig39655162007-10-21 16:42:17 -07002131static const struct export_operations shmem_export_ops = {
David M. Grimes91828a42006-10-17 00:09:45 -07002132 .get_parent = shmem_get_parent,
David M. Grimes91828a42006-10-17 00:09:45 -07002133 .encode_fh = shmem_encode_fh,
Christoph Hellwig480b1162007-10-21 16:42:13 -07002134 .fh_to_dentry = shmem_fh_to_dentry,
David M. Grimes91828a42006-10-17 00:09:45 -07002135};
2136
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002137static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
2138 bool remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139{
2140 char *this_char, *value, *rest;
2141
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002142 while (options != NULL) {
2143 this_char = options;
2144 for (;;) {
2145 /*
2146 * NUL-terminate this option: unfortunately,
2147 * mount options form a comma-separated list,
2148 * but mpol's nodelist may also contain commas.
2149 */
2150 options = strchr(options, ',');
2151 if (options == NULL)
2152 break;
2153 options++;
2154 if (!isdigit(*options)) {
2155 options[-1] = '\0';
2156 break;
2157 }
2158 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002159 if (!*this_char)
2160 continue;
2161 if ((value = strchr(this_char,'=')) != NULL) {
2162 *value++ = 0;
2163 } else {
2164 printk(KERN_ERR
2165 "tmpfs: No value for mount option '%s'\n",
2166 this_char);
2167 return 1;
2168 }
2169
2170 if (!strcmp(this_char,"size")) {
2171 unsigned long long size;
2172 size = memparse(value,&rest);
2173 if (*rest == '%') {
2174 size <<= PAGE_SHIFT;
2175 size *= totalram_pages;
2176 do_div(size, 100);
2177 rest++;
2178 }
2179 if (*rest)
2180 goto bad_val;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002181 sbinfo->max_blocks =
2182 DIV_ROUND_UP(size, PAGE_CACHE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002183 } else if (!strcmp(this_char,"nr_blocks")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002184 sbinfo->max_blocks = memparse(value, &rest);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002185 if (*rest)
2186 goto bad_val;
2187 } else if (!strcmp(this_char,"nr_inodes")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002188 sbinfo->max_inodes = memparse(value, &rest);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002189 if (*rest)
2190 goto bad_val;
2191 } else if (!strcmp(this_char,"mode")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002192 if (remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002193 continue;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002194 sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195 if (*rest)
2196 goto bad_val;
2197 } else if (!strcmp(this_char,"uid")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002198 if (remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002199 continue;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002200 sbinfo->uid = simple_strtoul(value, &rest, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002201 if (*rest)
2202 goto bad_val;
2203 } else if (!strcmp(this_char,"gid")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002204 if (remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002205 continue;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002206 sbinfo->gid = simple_strtoul(value, &rest, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 if (*rest)
2208 goto bad_val;
Robin Holt7339ff82006-01-14 13:20:48 -08002209 } else if (!strcmp(this_char,"mpol")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002210 if (shmem_parse_mpol(value, &sbinfo->policy,
2211 &sbinfo->policy_nodes))
Robin Holt7339ff82006-01-14 13:20:48 -08002212 goto bad_val;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 } else {
2214 printk(KERN_ERR "tmpfs: Bad mount option %s\n",
2215 this_char);
2216 return 1;
2217 }
2218 }
2219 return 0;
2220
2221bad_val:
2222 printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
2223 value, this_char);
2224 return 1;
2225
2226}
2227
2228static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
2229{
2230 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002231 struct shmem_sb_info config = *sbinfo;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002232 unsigned long blocks;
2233 unsigned long inodes;
2234 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002235
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002236 if (shmem_parse_options(data, &config, true))
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002237 return error;
2238
2239 spin_lock(&sbinfo->stat_lock);
2240 blocks = sbinfo->max_blocks - sbinfo->free_blocks;
2241 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002242 if (config.max_blocks < blocks)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002243 goto out;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002244 if (config.max_inodes < inodes)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002245 goto out;
2246 /*
2247 * Those tests also disallow limited->unlimited while any are in
2248 * use, so i_blocks will always be zero when max_blocks is zero;
2249 * but we must separately disallow unlimited->limited, because
2250 * in that case we have no record of how much is already in use.
2251 */
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002252 if (config.max_blocks && !sbinfo->max_blocks)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002253 goto out;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002254 if (config.max_inodes && !sbinfo->max_inodes)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002255 goto out;
2256
2257 error = 0;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002258 sbinfo->max_blocks = config.max_blocks;
2259 sbinfo->free_blocks = config.max_blocks - blocks;
2260 sbinfo->max_inodes = config.max_inodes;
2261 sbinfo->free_inodes = config.max_inodes - inodes;
2262 sbinfo->policy = config.policy;
2263 sbinfo->policy_nodes = config.policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002264out:
2265 spin_unlock(&sbinfo->stat_lock);
2266 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002268
2269static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs)
2270{
2271 struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb);
2272
2273 if (sbinfo->max_blocks != shmem_default_max_blocks())
2274 seq_printf(seq, ",size=%luk",
2275 sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10));
2276 if (sbinfo->max_inodes != shmem_default_max_inodes())
2277 seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
2278 if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
2279 seq_printf(seq, ",mode=%03o", sbinfo->mode);
2280 if (sbinfo->uid != 0)
2281 seq_printf(seq, ",uid=%u", sbinfo->uid);
2282 if (sbinfo->gid != 0)
2283 seq_printf(seq, ",gid=%u", sbinfo->gid);
2284 shmem_show_mpol(seq, sbinfo->policy, sbinfo->policy_nodes);
2285 return 0;
2286}
2287#endif /* CONFIG_TMPFS */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002288
2289static void shmem_put_super(struct super_block *sb)
2290{
2291 kfree(sb->s_fs_info);
2292 sb->s_fs_info = NULL;
2293}
2294
Linus Torvalds1da177e2005-04-16 15:20:36 -07002295static int shmem_fill_super(struct super_block *sb,
2296 void *data, int silent)
2297{
2298 struct inode *inode;
2299 struct dentry *root;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002300 struct shmem_sb_info *sbinfo;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002301 int err = -ENOMEM;
2302
2303 /* Round up to L1_CACHE_BYTES to resist false sharing */
2304 sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
2305 L1_CACHE_BYTES), GFP_KERNEL);
2306 if (!sbinfo)
2307 return -ENOMEM;
2308
2309 sbinfo->max_blocks = 0;
2310 sbinfo->max_inodes = 0;
2311 sbinfo->mode = S_IRWXUGO | S_ISVTX;
2312 sbinfo->uid = current->fsuid;
2313 sbinfo->gid = current->fsgid;
2314 sbinfo->policy = MPOL_DEFAULT;
2315 sbinfo->policy_nodes = node_states[N_HIGH_MEMORY];
2316 sb->s_fs_info = sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002317
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002318#ifdef CONFIG_TMPFS
Linus Torvalds1da177e2005-04-16 15:20:36 -07002319 /*
2320 * Per default we only allow half of the physical ram per
2321 * tmpfs instance, limiting inodes to one per page of lowmem;
2322 * but the internal instance is left unlimited.
2323 */
2324 if (!(sb->s_flags & MS_NOUSER)) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002325 sbinfo->max_blocks = shmem_default_max_blocks();
2326 sbinfo->max_inodes = shmem_default_max_inodes();
2327 if (shmem_parse_options(data, sbinfo, false)) {
2328 err = -EINVAL;
2329 goto failed;
2330 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002331 }
David M. Grimes91828a42006-10-17 00:09:45 -07002332 sb->s_export_op = &shmem_export_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333#else
2334 sb->s_flags |= MS_NOUSER;
2335#endif
2336
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002337 spin_lock_init(&sbinfo->stat_lock);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002338 sbinfo->free_blocks = sbinfo->max_blocks;
2339 sbinfo->free_inodes = sbinfo->max_inodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002340
Linus Torvalds1da177e2005-04-16 15:20:36 -07002341 sb->s_maxbytes = SHMEM_MAX_BYTES;
2342 sb->s_blocksize = PAGE_CACHE_SIZE;
2343 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2344 sb->s_magic = TMPFS_MAGIC;
2345 sb->s_op = &shmem_ops;
Robin H. Johnsoncfd95a92006-06-12 21:50:25 +01002346 sb->s_time_gran = 1;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002347#ifdef CONFIG_TMPFS_POSIX_ACL
2348 sb->s_xattr = shmem_xattr_handlers;
2349 sb->s_flags |= MS_POSIXACL;
2350#endif
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002351
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002352 inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353 if (!inode)
2354 goto failed;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002355 inode->i_uid = sbinfo->uid;
2356 inode->i_gid = sbinfo->gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002357 root = d_alloc_root(inode);
2358 if (!root)
2359 goto failed_iput;
2360 sb->s_root = root;
2361 return 0;
2362
2363failed_iput:
2364 iput(inode);
2365failed:
2366 shmem_put_super(sb);
2367 return err;
2368}
2369
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002370static struct kmem_cache *shmem_inode_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002371
2372static struct inode *shmem_alloc_inode(struct super_block *sb)
2373{
2374 struct shmem_inode_info *p;
Christoph Lametere94b1762006-12-06 20:33:17 -08002375 p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002376 if (!p)
2377 return NULL;
2378 return &p->vfs_inode;
2379}
2380
2381static void shmem_destroy_inode(struct inode *inode)
2382{
2383 if ((inode->i_mode & S_IFMT) == S_IFREG) {
2384 /* only struct inode is valid if it's an inline symlink */
2385 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
2386 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002387 shmem_acl_destroy_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
2389}
2390
Christoph Lameter4ba9b9d2007-10-16 23:25:51 -07002391static void init_once(struct kmem_cache *cachep, void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392{
2393 struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
2394
Christoph Lametera35afb82007-05-16 22:10:57 -07002395 inode_init_once(&p->vfs_inode);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002396#ifdef CONFIG_TMPFS_POSIX_ACL
Christoph Lametera35afb82007-05-16 22:10:57 -07002397 p->i_acl = NULL;
2398 p->i_default_acl = NULL;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002399#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002400}
2401
2402static int init_inodecache(void)
2403{
2404 shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
2405 sizeof(struct shmem_inode_info),
Alexey Dobriyan040b5c62007-10-16 23:26:10 -07002406 0, SLAB_PANIC, init_once);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 return 0;
2408}
2409
2410static void destroy_inodecache(void)
2411{
Alexey Dobriyan1a1d92c2006-09-27 01:49:40 -07002412 kmem_cache_destroy(shmem_inode_cachep);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002413}
2414
Christoph Hellwigf5e54d62006-06-28 04:26:44 -07002415static const struct address_space_operations shmem_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002416 .writepage = shmem_writepage,
Ken Chen76719322007-02-10 01:43:15 -08002417 .set_page_dirty = __set_page_dirty_no_writeback,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002418#ifdef CONFIG_TMPFS
Hugh Dickinsae976412007-06-04 10:00:39 +02002419 .readpage = shmem_readpage,
Nick Piggin800d15a2007-10-16 01:25:03 -07002420 .write_begin = shmem_write_begin,
2421 .write_end = shmem_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002422#endif
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -07002423 .migratepage = migrate_page,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424};
2425
Helge Deller15ad7cd2006-12-06 20:40:36 -08002426static const struct file_operations shmem_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002427 .mmap = shmem_mmap,
2428#ifdef CONFIG_TMPFS
2429 .llseek = generic_file_llseek,
2430 .read = shmem_file_read,
Hugh Dickins5402b972008-02-04 22:28:44 -08002431 .write = do_sync_write,
2432 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002433 .fsync = simple_sync_file,
Hugh Dickinsae976412007-06-04 10:00:39 +02002434 .splice_read = generic_file_splice_read,
2435 .splice_write = generic_file_splice_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002436#endif
2437};
2438
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002439static const struct inode_operations shmem_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002440 .truncate = shmem_truncate,
2441 .setattr = shmem_notify_change,
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002442 .truncate_range = shmem_truncate_range,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002443#ifdef CONFIG_TMPFS_POSIX_ACL
2444 .setxattr = generic_setxattr,
2445 .getxattr = generic_getxattr,
2446 .listxattr = generic_listxattr,
2447 .removexattr = generic_removexattr,
2448 .permission = shmem_permission,
2449#endif
2450
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451};
2452
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002453static const struct inode_operations shmem_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002454#ifdef CONFIG_TMPFS
2455 .create = shmem_create,
2456 .lookup = simple_lookup,
2457 .link = shmem_link,
2458 .unlink = shmem_unlink,
2459 .symlink = shmem_symlink,
2460 .mkdir = shmem_mkdir,
2461 .rmdir = shmem_rmdir,
2462 .mknod = shmem_mknod,
2463 .rename = shmem_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002464#endif
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002465#ifdef CONFIG_TMPFS_POSIX_ACL
2466 .setattr = shmem_notify_change,
2467 .setxattr = generic_setxattr,
2468 .getxattr = generic_getxattr,
2469 .listxattr = generic_listxattr,
2470 .removexattr = generic_removexattr,
2471 .permission = shmem_permission,
2472#endif
2473};
2474
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002475static const struct inode_operations shmem_special_inode_operations = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002476#ifdef CONFIG_TMPFS_POSIX_ACL
2477 .setattr = shmem_notify_change,
2478 .setxattr = generic_setxattr,
2479 .getxattr = generic_getxattr,
2480 .listxattr = generic_listxattr,
2481 .removexattr = generic_removexattr,
2482 .permission = shmem_permission,
2483#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002484};
2485
Hugh Dickins759b9772007-03-05 00:30:28 -08002486static const struct super_operations shmem_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002487 .alloc_inode = shmem_alloc_inode,
2488 .destroy_inode = shmem_destroy_inode,
2489#ifdef CONFIG_TMPFS
2490 .statfs = shmem_statfs,
2491 .remount_fs = shmem_remount_fs,
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002492 .show_options = shmem_show_options,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002493#endif
2494 .delete_inode = shmem_delete_inode,
2495 .drop_inode = generic_delete_inode,
2496 .put_super = shmem_put_super,
2497};
2498
2499static struct vm_operations_struct shmem_vm_ops = {
Nick Piggin54cb8822007-07-19 01:46:59 -07002500 .fault = shmem_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002501#ifdef CONFIG_NUMA
2502 .set_policy = shmem_set_policy,
2503 .get_policy = shmem_get_policy,
2504#endif
2505};
2506
2507
David Howells454e2392006-06-23 02:02:57 -07002508static int shmem_get_sb(struct file_system_type *fs_type,
2509 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002510{
David Howells454e2392006-06-23 02:02:57 -07002511 return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002512}
2513
2514static struct file_system_type tmpfs_fs_type = {
2515 .owner = THIS_MODULE,
2516 .name = "tmpfs",
2517 .get_sb = shmem_get_sb,
2518 .kill_sb = kill_litter_super,
2519};
2520static struct vfsmount *shm_mnt;
2521
2522static int __init init_tmpfs(void)
2523{
2524 int error;
2525
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -07002526 error = bdi_init(&shmem_backing_dev_info);
2527 if (error)
2528 goto out4;
2529
Linus Torvalds1da177e2005-04-16 15:20:36 -07002530 error = init_inodecache();
2531 if (error)
2532 goto out3;
2533
2534 error = register_filesystem(&tmpfs_fs_type);
2535 if (error) {
2536 printk(KERN_ERR "Could not register tmpfs\n");
2537 goto out2;
2538 }
Greg Kroah-Hartman95dc1122005-06-20 21:15:16 -07002539
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -04002540 shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002541 tmpfs_fs_type.name, NULL);
2542 if (IS_ERR(shm_mnt)) {
2543 error = PTR_ERR(shm_mnt);
2544 printk(KERN_ERR "Could not kern_mount tmpfs\n");
2545 goto out1;
2546 }
2547 return 0;
2548
2549out1:
2550 unregister_filesystem(&tmpfs_fs_type);
2551out2:
2552 destroy_inodecache();
2553out3:
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -07002554 bdi_destroy(&shmem_backing_dev_info);
2555out4:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002556 shm_mnt = ERR_PTR(error);
2557 return error;
2558}
2559module_init(init_tmpfs)
2560
2561/*
2562 * shmem_file_setup - get an unlinked file living in tmpfs
2563 *
2564 * @name: name for dentry (to be seen in /proc/<pid>/maps
2565 * @size: size to be set for the file
2566 *
2567 */
2568struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
2569{
2570 int error;
2571 struct file *file;
2572 struct inode *inode;
2573 struct dentry *dentry, *root;
2574 struct qstr this;
2575
2576 if (IS_ERR(shm_mnt))
2577 return (void *)shm_mnt;
2578
2579 if (size < 0 || size > SHMEM_MAX_BYTES)
2580 return ERR_PTR(-EINVAL);
2581
2582 if (shmem_acct_size(flags, size))
2583 return ERR_PTR(-ENOMEM);
2584
2585 error = -ENOMEM;
2586 this.name = name;
2587 this.len = strlen(name);
2588 this.hash = 0; /* will go */
2589 root = shm_mnt->mnt_root;
2590 dentry = d_alloc(root, &this);
2591 if (!dentry)
2592 goto put_memory;
2593
2594 error = -ENFILE;
2595 file = get_empty_filp();
2596 if (!file)
2597 goto put_dentry;
2598
2599 error = -ENOSPC;
2600 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
2601 if (!inode)
2602 goto close_file;
2603
2604 SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
2605 d_instantiate(dentry, inode);
2606 inode->i_size = size;
2607 inode->i_nlink = 0; /* It is unlinked */
Dave Hansence8d2cd2007-10-16 23:31:13 -07002608 init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
2609 &shmem_file_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002610 return file;
2611
2612close_file:
2613 put_filp(file);
2614put_dentry:
2615 dput(dentry);
2616put_memory:
2617 shmem_unacct_size(flags, size);
2618 return ERR_PTR(error);
2619}
2620
2621/*
2622 * shmem_zero_setup - setup a shared anonymous mapping
2623 *
2624 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2625 */
2626int shmem_zero_setup(struct vm_area_struct *vma)
2627{
2628 struct file *file;
2629 loff_t size = vma->vm_end - vma->vm_start;
2630
2631 file = shmem_file_setup("dev/zero", size, vma->vm_flags);
2632 if (IS_ERR(file))
2633 return PTR_ERR(file);
2634
2635 if (vma->vm_file)
2636 fput(vma->vm_file);
2637 vma->vm_file = file;
2638 vma->vm_ops = &shmem_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002639 return 0;
2640}