blob: d713239ce2ce72be6097a1ad478ce1b04798773d [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 *
Matt Mackall853ac432009-01-06 14:40:20 -080017 * tiny-shmem:
18 * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
19 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070020 * This file is released under the GPL.
21 */
22
Matt Mackall853ac432009-01-06 14:40:20 -080023#include <linux/fs.h>
24#include <linux/init.h>
25#include <linux/vfs.h>
26#include <linux/mount.h>
Hugh Dickinscaefba12009-04-13 14:40:12 -070027#include <linux/pagemap.h>
Matt Mackall853ac432009-01-06 14:40:20 -080028#include <linux/file.h>
29#include <linux/mm.h>
30#include <linux/module.h>
31#include <linux/swap.h>
Mimi Zohared850a52009-02-10 23:01:19 -050032#include <linux/ima.h>
Matt Mackall853ac432009-01-06 14:40:20 -080033
34static struct vfsmount *shm_mnt;
35
36#ifdef CONFIG_SHMEM
Linus Torvalds1da177e2005-04-16 15:20:36 -070037/*
38 * This virtual memory filesystem is heavily based on the ramfs. It
39 * extends ramfs by the ability to use swap and honor resource limits
40 * which makes it a completely usable filesystem.
41 */
42
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070043#include <linux/xattr.h>
Christoph Hellwiga5694252007-07-17 04:04:28 -070044#include <linux/exportfs.h>
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070045#include <linux/generic_acl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#include <linux/mman.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/backing-dev.h>
50#include <linux/shmem_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051#include <linux/writeback.h>
52#include <linux/vfs.h>
53#include <linux/blkdev.h>
54#include <linux/security.h>
55#include <linux/swapops.h>
56#include <linux/mempolicy.h>
57#include <linux/namei.h>
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +000058#include <linux/ctype.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070059#include <linux/migrate.h>
Christoph Lameterc1f60a52006-09-25 23:31:11 -070060#include <linux/highmem.h>
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -080061#include <linux/seq_file.h>
Mimi Zohar92562922008-10-07 14:00:12 -040062#include <linux/magic.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070063
Linus Torvalds1da177e2005-04-16 15:20:36 -070064#include <asm/uaccess.h>
65#include <asm/div64.h>
66#include <asm/pgtable.h>
67
Hugh Dickinscaefba12009-04-13 14:40:12 -070068/*
69 * The maximum size of a shmem/tmpfs file is limited by the maximum size of
70 * its triple-indirect swap vector - see illustration at shmem_swp_entry().
71 *
72 * With 4kB page size, maximum file size is just over 2TB on a 32-bit kernel,
73 * but one eighth of that on a 64-bit kernel. With 8kB page size, maximum
74 * file size is just over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel,
75 * MAX_LFS_FILESIZE being then more restrictive than swap vector layout.
76 *
77 * We use / and * instead of shifts in the definitions below, so that the swap
78 * vector can be tested with small even values (e.g. 20) for ENTRIES_PER_PAGE.
79 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070080#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
Yuri Tikhonov61609d02009-04-13 14:40:11 -070081#define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
Hugh Dickinscaefba12009-04-13 14:40:12 -070082
83#define SHMSWP_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
84#define SHMSWP_MAX_BYTES (SHMSWP_MAX_INDEX << PAGE_CACHE_SHIFT)
85
86#define SHMEM_MAX_BYTES min_t(unsigned long long, SHMSWP_MAX_BYTES, MAX_LFS_FILESIZE)
87#define SHMEM_MAX_INDEX ((unsigned long)((SHMEM_MAX_BYTES+1) >> PAGE_CACHE_SHIFT))
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090#define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
91
92/* info->flags needs VM_flags to handle pagein/truncate races efficiently */
93#define SHMEM_PAGEIN VM_READ
94#define SHMEM_TRUNCATE VM_WRITE
95
96/* Definition to limit shmem_truncate's steps between cond_rescheds */
97#define LATENCY_LIMIT 64
98
99/* Pretend that each entry is of this size in directory's i_size */
100#define BOGO_DIRENT_SIZE 20
101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
103enum sgp_type {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 SGP_READ, /* don't exceed i_size, don't allocate page */
105 SGP_CACHE, /* don't exceed i_size, may allocate page */
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -0800106 SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 SGP_WRITE, /* may exceed i_size, may allocate page */
108};
109
Andrew Mortonb76db732008-02-08 04:21:49 -0800110#ifdef CONFIG_TMPFS
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800111static unsigned long shmem_default_max_blocks(void)
112{
113 return totalram_pages / 2;
114}
115
116static unsigned long shmem_default_max_inodes(void)
117{
118 return min(totalram_pages - totalhigh_pages, totalram_pages / 2);
119}
Andrew Mortonb76db732008-02-08 04:21:49 -0800120#endif
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800121
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122static int shmem_getpage(struct inode *inode, unsigned long idx,
123 struct page **pagep, enum sgp_type sgp, int *type);
124
Al Viro6daa0e22005-10-21 03:18:50 -0400125static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126{
127 /*
128 * The above definition of ENTRIES_PER_PAGE, and the use of
129 * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
130 * might be reconsidered if it ever diverges from PAGE_SIZE.
Mel Gorman769848c2007-07-17 04:03:05 -0700131 *
Mel Gormane12ba742007-10-16 01:25:52 -0700132 * Mobility flags are masked out as swap vectors cannot move
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 */
Mel Gormane12ba742007-10-16 01:25:52 -0700134 return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO,
Mel Gorman769848c2007-07-17 04:03:05 -0700135 PAGE_CACHE_SHIFT-PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136}
137
138static inline void shmem_dir_free(struct page *page)
139{
140 __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT);
141}
142
143static struct page **shmem_dir_map(struct page *page)
144{
145 return (struct page **)kmap_atomic(page, KM_USER0);
146}
147
148static inline void shmem_dir_unmap(struct page **dir)
149{
150 kunmap_atomic(dir, KM_USER0);
151}
152
153static swp_entry_t *shmem_swp_map(struct page *page)
154{
155 return (swp_entry_t *)kmap_atomic(page, KM_USER1);
156}
157
158static inline void shmem_swp_balance_unmap(void)
159{
160 /*
161 * When passing a pointer to an i_direct entry, to code which
162 * also handles indirect entries and so will shmem_swp_unmap,
163 * we must arrange for the preempt count to remain in balance.
164 * What kmap_atomic of a lowmem page does depends on config
165 * and architecture, so pretend to kmap_atomic some lowmem page.
166 */
167 (void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
168}
169
170static inline void shmem_swp_unmap(swp_entry_t *entry)
171{
172 kunmap_atomic(entry, KM_USER1);
173}
174
175static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
176{
177 return sb->s_fs_info;
178}
179
180/*
181 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
182 * for shared memory and for shared anonymous (/dev/zero) mappings
183 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
184 * consistent with the pre-accounting of private mappings ...
185 */
186static inline int shmem_acct_size(unsigned long flags, loff_t size)
187{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000188 return (flags & VM_NORESERVE) ?
189 0 : security_vm_enough_memory_kern(VM_ACCT(size));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190}
191
192static inline void shmem_unacct_size(unsigned long flags, loff_t size)
193{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000194 if (!(flags & VM_NORESERVE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 vm_unacct_memory(VM_ACCT(size));
196}
197
198/*
199 * ... whereas tmpfs objects are accounted incrementally as
200 * pages are allocated, in order to allow huge sparse files.
201 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
202 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
203 */
204static inline int shmem_acct_block(unsigned long flags)
205{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000206 return (flags & VM_NORESERVE) ?
207 security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208}
209
210static inline void shmem_unacct_blocks(unsigned long flags, long pages)
211{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000212 if (flags & VM_NORESERVE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
214}
215
Hugh Dickins759b9772007-03-05 00:30:28 -0800216static const struct super_operations shmem_ops;
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700217static const struct address_space_operations shmem_aops;
Helge Deller15ad7cd2006-12-06 20:40:36 -0800218static const struct file_operations shmem_file_operations;
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800219static const struct inode_operations shmem_inode_operations;
220static const struct inode_operations shmem_dir_inode_operations;
221static const struct inode_operations shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222static struct vm_operations_struct shmem_vm_ops;
223
Ravikiran G Thirumalai6c231b72005-09-06 15:17:45 -0700224static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 .ra_pages = 0, /* No readahead */
Rik van Riel4f98a2f2008-10-18 20:26:32 -0700226 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 .unplug_io_fn = default_unplug_io_fn,
228};
229
230static LIST_HEAD(shmem_swaplist);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800231static DEFINE_MUTEX(shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
233static void shmem_free_blocks(struct inode *inode, long pages)
234{
235 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700236 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 spin_lock(&sbinfo->stat_lock);
238 sbinfo->free_blocks += pages;
239 inode->i_blocks -= pages*BLOCKS_PER_PAGE;
240 spin_unlock(&sbinfo->stat_lock);
241 }
242}
243
Pavel Emelyanov5b04c682008-02-04 22:28:47 -0800244static int shmem_reserve_inode(struct super_block *sb)
245{
246 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
247 if (sbinfo->max_inodes) {
248 spin_lock(&sbinfo->stat_lock);
249 if (!sbinfo->free_inodes) {
250 spin_unlock(&sbinfo->stat_lock);
251 return -ENOSPC;
252 }
253 sbinfo->free_inodes--;
254 spin_unlock(&sbinfo->stat_lock);
255 }
256 return 0;
257}
258
259static void shmem_free_inode(struct super_block *sb)
260{
261 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
262 if (sbinfo->max_inodes) {
263 spin_lock(&sbinfo->stat_lock);
264 sbinfo->free_inodes++;
265 spin_unlock(&sbinfo->stat_lock);
266 }
267}
268
Randy Dunlap46711812008-03-19 17:00:41 -0700269/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 * shmem_recalc_inode - recalculate the size of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 * @inode: inode to recalc
272 *
273 * We have to calculate the free blocks since the mm can drop
274 * undirtied hole pages behind our back.
275 *
276 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
277 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
278 *
279 * It has to be called with the spinlock held.
280 */
281static void shmem_recalc_inode(struct inode *inode)
282{
283 struct shmem_inode_info *info = SHMEM_I(inode);
284 long freed;
285
286 freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
287 if (freed > 0) {
288 info->alloced -= freed;
289 shmem_unacct_blocks(info->flags, freed);
290 shmem_free_blocks(inode, freed);
291 }
292}
293
Randy Dunlap46711812008-03-19 17:00:41 -0700294/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 * shmem_swp_entry - find the swap vector position in the info structure
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 * @info: info structure for the inode
297 * @index: index of the page to find
298 * @page: optional page to add to the structure. Has to be preset to
299 * all zeros
300 *
301 * If there is no space allocated yet it will return NULL when
302 * page is NULL, else it will use the page for the needed block,
303 * setting it to NULL on return to indicate that it has been used.
304 *
305 * The swap vector is organized the following way:
306 *
307 * There are SHMEM_NR_DIRECT entries directly stored in the
308 * shmem_inode_info structure. So small files do not need an addional
309 * allocation.
310 *
311 * For pages with index > SHMEM_NR_DIRECT there is the pointer
312 * i_indirect which points to a page which holds in the first half
313 * doubly indirect blocks, in the second half triple indirect blocks:
314 *
315 * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the
316 * following layout (for SHMEM_NR_DIRECT == 16):
317 *
318 * i_indirect -> dir --> 16-19
319 * | +-> 20-23
320 * |
321 * +-->dir2 --> 24-27
322 * | +-> 28-31
323 * | +-> 32-35
324 * | +-> 36-39
325 * |
326 * +-->dir3 --> 40-43
327 * +-> 44-47
328 * +-> 48-51
329 * +-> 52-55
330 */
331static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page)
332{
333 unsigned long offset;
334 struct page **dir;
335 struct page *subdir;
336
337 if (index < SHMEM_NR_DIRECT) {
338 shmem_swp_balance_unmap();
339 return info->i_direct+index;
340 }
341 if (!info->i_indirect) {
342 if (page) {
343 info->i_indirect = *page;
344 *page = NULL;
345 }
346 return NULL; /* need another page */
347 }
348
349 index -= SHMEM_NR_DIRECT;
350 offset = index % ENTRIES_PER_PAGE;
351 index /= ENTRIES_PER_PAGE;
352 dir = shmem_dir_map(info->i_indirect);
353
354 if (index >= ENTRIES_PER_PAGE/2) {
355 index -= ENTRIES_PER_PAGE/2;
356 dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE;
357 index %= ENTRIES_PER_PAGE;
358 subdir = *dir;
359 if (!subdir) {
360 if (page) {
361 *dir = *page;
362 *page = NULL;
363 }
364 shmem_dir_unmap(dir);
365 return NULL; /* need another page */
366 }
367 shmem_dir_unmap(dir);
368 dir = shmem_dir_map(subdir);
369 }
370
371 dir += index;
372 subdir = *dir;
373 if (!subdir) {
374 if (!page || !(subdir = *page)) {
375 shmem_dir_unmap(dir);
376 return NULL; /* need a page */
377 }
378 *dir = subdir;
379 *page = NULL;
380 }
381 shmem_dir_unmap(dir);
382 return shmem_swp_map(subdir) + offset;
383}
384
385static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
386{
387 long incdec = value? 1: -1;
388
389 entry->val = value;
390 info->swapped += incdec;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700391 if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
392 struct page *page = kmap_atomic_to_page(entry);
393 set_page_private(page, page_private(page) + incdec);
394 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395}
396
Randy Dunlap46711812008-03-19 17:00:41 -0700397/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 * shmem_swp_alloc - get the position of the swap entry for the page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 * @info: info structure for the inode
400 * @index: index of the page to find
401 * @sgp: check and recheck i_size? skip allocation?
Randy Dunlap46711812008-03-19 17:00:41 -0700402 *
403 * If the entry does not exist, allocate it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 */
405static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp)
406{
407 struct inode *inode = &info->vfs_inode;
408 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
409 struct page *page = NULL;
410 swp_entry_t *entry;
411
412 if (sgp != SGP_WRITE &&
413 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
414 return ERR_PTR(-EINVAL);
415
416 while (!(entry = shmem_swp_entry(info, index, &page))) {
417 if (sgp == SGP_READ)
418 return shmem_swp_map(ZERO_PAGE(0));
419 /*
420 * Test free_blocks against 1 not 0, since we have 1 data
421 * page (and perhaps indirect index pages) yet to allocate:
422 * a waste to allocate index if we cannot allocate data.
423 */
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700424 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 spin_lock(&sbinfo->stat_lock);
426 if (sbinfo->free_blocks <= 1) {
427 spin_unlock(&sbinfo->stat_lock);
428 return ERR_PTR(-ENOSPC);
429 }
430 sbinfo->free_blocks--;
431 inode->i_blocks += BLOCKS_PER_PAGE;
432 spin_unlock(&sbinfo->stat_lock);
433 }
434
435 spin_unlock(&info->lock);
Mel Gorman769848c2007-07-17 04:03:05 -0700436 page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping));
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700437 if (page)
438 set_page_private(page, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 spin_lock(&info->lock);
440
441 if (!page) {
442 shmem_free_blocks(inode, 1);
443 return ERR_PTR(-ENOMEM);
444 }
445 if (sgp != SGP_WRITE &&
446 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
447 entry = ERR_PTR(-EINVAL);
448 break;
449 }
450 if (info->next_index <= index)
451 info->next_index = index + 1;
452 }
453 if (page) {
454 /* another task gave its page, or truncated the file */
455 shmem_free_blocks(inode, 1);
456 shmem_dir_free(page);
457 }
458 if (info->next_index <= index && !IS_ERR(entry))
459 info->next_index = index + 1;
460 return entry;
461}
462
Randy Dunlap46711812008-03-19 17:00:41 -0700463/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 * shmem_free_swp - free some swap entries in a directory
Hugh Dickins1ae70002007-03-29 01:20:36 -0700465 * @dir: pointer to the directory
466 * @edir: pointer after last entry of the directory
467 * @punch_lock: pointer to spinlock when needed for the holepunch case
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 */
Hugh Dickins1ae70002007-03-29 01:20:36 -0700469static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
470 spinlock_t *punch_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471{
Hugh Dickins1ae70002007-03-29 01:20:36 -0700472 spinlock_t *punch_unlock = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 swp_entry_t *ptr;
474 int freed = 0;
475
476 for (ptr = dir; ptr < edir; ptr++) {
477 if (ptr->val) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700478 if (unlikely(punch_lock)) {
479 punch_unlock = punch_lock;
480 punch_lock = NULL;
481 spin_lock(punch_unlock);
482 if (!ptr->val)
483 continue;
484 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 free_swap_and_cache(*ptr);
486 *ptr = (swp_entry_t){0};
487 freed++;
488 }
489 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700490 if (punch_unlock)
491 spin_unlock(punch_unlock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 return freed;
493}
494
Hugh Dickins1ae70002007-03-29 01:20:36 -0700495static int shmem_map_and_free_swp(struct page *subdir, int offset,
496 int limit, struct page ***dir, spinlock_t *punch_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497{
498 swp_entry_t *ptr;
499 int freed = 0;
500
501 ptr = shmem_swp_map(subdir);
502 for (; offset < limit; offset += LATENCY_LIMIT) {
503 int size = limit - offset;
504 if (size > LATENCY_LIMIT)
505 size = LATENCY_LIMIT;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700506 freed += shmem_free_swp(ptr+offset, ptr+offset+size,
507 punch_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 if (need_resched()) {
509 shmem_swp_unmap(ptr);
510 if (*dir) {
511 shmem_dir_unmap(*dir);
512 *dir = NULL;
513 }
514 cond_resched();
515 ptr = shmem_swp_map(subdir);
516 }
517 }
518 shmem_swp_unmap(ptr);
519 return freed;
520}
521
522static void shmem_free_pages(struct list_head *next)
523{
524 struct page *page;
525 int freed = 0;
526
527 do {
528 page = container_of(next, struct page, lru);
529 next = next->next;
530 shmem_dir_free(page);
531 freed++;
532 if (freed >= LATENCY_LIMIT) {
533 cond_resched();
534 freed = 0;
535 }
536 } while (next);
537}
538
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800539static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540{
541 struct shmem_inode_info *info = SHMEM_I(inode);
542 unsigned long idx;
543 unsigned long size;
544 unsigned long limit;
545 unsigned long stage;
546 unsigned long diroff;
547 struct page **dir;
548 struct page *topdir;
549 struct page *middir;
550 struct page *subdir;
551 swp_entry_t *ptr;
552 LIST_HEAD(pages_to_free);
553 long nr_pages_to_free = 0;
554 long nr_swaps_freed = 0;
555 int offset;
556 int freed;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700557 int punch_hole;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700558 spinlock_t *needs_lock;
559 spinlock_t *punch_lock;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700560 unsigned long upper_limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561
562 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800563 idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 if (idx >= info->next_index)
565 return;
566
567 spin_lock(&info->lock);
568 info->flags |= SHMEM_TRUNCATE;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800569 if (likely(end == (loff_t) -1)) {
570 limit = info->next_index;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700571 upper_limit = SHMEM_MAX_INDEX;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800572 info->next_index = idx;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700573 needs_lock = NULL;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700574 punch_hole = 0;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800575 } else {
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700576 if (end + 1 >= inode->i_size) { /* we may free a little more */
577 limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >>
578 PAGE_CACHE_SHIFT;
579 upper_limit = SHMEM_MAX_INDEX;
580 } else {
581 limit = (end + 1) >> PAGE_CACHE_SHIFT;
582 upper_limit = limit;
583 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700584 needs_lock = &info->lock;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800585 punch_hole = 1;
586 }
587
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 topdir = info->i_indirect;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800589 if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 info->i_indirect = NULL;
591 nr_pages_to_free++;
592 list_add(&topdir->lru, &pages_to_free);
593 }
594 spin_unlock(&info->lock);
595
596 if (info->swapped && idx < SHMEM_NR_DIRECT) {
597 ptr = info->i_direct;
598 size = limit;
599 if (size > SHMEM_NR_DIRECT)
600 size = SHMEM_NR_DIRECT;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700601 nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 }
Badari Pulavarty92a3d032006-12-22 01:06:23 -0800603
604 /*
605 * If there are no indirect blocks or we are punching a hole
606 * below indirect blocks, nothing to be done.
607 */
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700608 if (!topdir || limit <= SHMEM_NR_DIRECT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 goto done2;
610
Hugh Dickins1ae70002007-03-29 01:20:36 -0700611 /*
612 * The truncation case has already dropped info->lock, and we're safe
613 * because i_size and next_index have already been lowered, preventing
614 * access beyond. But in the punch_hole case, we still need to take
615 * the lock when updating the swap directory, because there might be
616 * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or
617 * shmem_writepage. However, whenever we find we can remove a whole
618 * directory page (not at the misaligned start or end of the range),
619 * we first NULLify its pointer in the level above, and then have no
620 * need to take the lock when updating its contents: needs_lock and
621 * punch_lock (either pointing to info->lock or NULL) manage this.
622 */
623
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700624 upper_limit -= SHMEM_NR_DIRECT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 limit -= SHMEM_NR_DIRECT;
626 idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
627 offset = idx % ENTRIES_PER_PAGE;
628 idx -= offset;
629
630 dir = shmem_dir_map(topdir);
631 stage = ENTRIES_PER_PAGEPAGE/2;
632 if (idx < ENTRIES_PER_PAGEPAGE/2) {
633 middir = topdir;
634 diroff = idx/ENTRIES_PER_PAGE;
635 } else {
636 dir += ENTRIES_PER_PAGE/2;
637 dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
638 while (stage <= idx)
639 stage += ENTRIES_PER_PAGEPAGE;
640 middir = *dir;
641 if (*dir) {
642 diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
643 ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700644 if (!diroff && !offset && upper_limit >= stage) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700645 if (needs_lock) {
646 spin_lock(needs_lock);
647 *dir = NULL;
648 spin_unlock(needs_lock);
649 needs_lock = NULL;
650 } else
651 *dir = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 nr_pages_to_free++;
653 list_add(&middir->lru, &pages_to_free);
654 }
655 shmem_dir_unmap(dir);
656 dir = shmem_dir_map(middir);
657 } else {
658 diroff = 0;
659 offset = 0;
660 idx = stage;
661 }
662 }
663
664 for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
665 if (unlikely(idx == stage)) {
666 shmem_dir_unmap(dir);
667 dir = shmem_dir_map(topdir) +
668 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
669 while (!*dir) {
670 dir++;
671 idx += ENTRIES_PER_PAGEPAGE;
672 if (idx >= limit)
673 goto done1;
674 }
675 stage = idx + ENTRIES_PER_PAGEPAGE;
676 middir = *dir;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700677 if (punch_hole)
678 needs_lock = &info->lock;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700679 if (upper_limit >= stage) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700680 if (needs_lock) {
681 spin_lock(needs_lock);
682 *dir = NULL;
683 spin_unlock(needs_lock);
684 needs_lock = NULL;
685 } else
686 *dir = NULL;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700687 nr_pages_to_free++;
688 list_add(&middir->lru, &pages_to_free);
689 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 shmem_dir_unmap(dir);
691 cond_resched();
692 dir = shmem_dir_map(middir);
693 diroff = 0;
694 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700695 punch_lock = needs_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 subdir = dir[diroff];
Hugh Dickins1ae70002007-03-29 01:20:36 -0700697 if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) {
698 if (needs_lock) {
699 spin_lock(needs_lock);
700 dir[diroff] = NULL;
701 spin_unlock(needs_lock);
702 punch_lock = NULL;
703 } else
704 dir[diroff] = NULL;
705 nr_pages_to_free++;
706 list_add(&subdir->lru, &pages_to_free);
707 }
708 if (subdir && page_private(subdir) /* has swap entries */) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 size = limit - idx;
710 if (size > ENTRIES_PER_PAGE)
711 size = ENTRIES_PER_PAGE;
712 freed = shmem_map_and_free_swp(subdir,
Hugh Dickins1ae70002007-03-29 01:20:36 -0700713 offset, size, &dir, punch_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 if (!dir)
715 dir = shmem_dir_map(middir);
716 nr_swaps_freed += freed;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700717 if (offset || punch_lock) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 spin_lock(&info->lock);
Hugh Dickins1ae70002007-03-29 01:20:36 -0700719 set_page_private(subdir,
720 page_private(subdir) - freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 spin_unlock(&info->lock);
Hugh Dickins1ae70002007-03-29 01:20:36 -0700722 } else
723 BUG_ON(page_private(subdir) != freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700725 offset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 }
727done1:
728 shmem_dir_unmap(dir);
729done2:
730 if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
731 /*
732 * Call truncate_inode_pages again: racing shmem_unuse_inode
733 * may have swizzled a page in from swap since vmtruncate or
734 * generic_delete_inode did it, before we lowered next_index.
735 * Also, though shmem_getpage checks i_size before adding to
736 * cache, no recheck after: so fix the narrow window there too.
Hugh Dickins16a10012007-03-29 01:20:37 -0700737 *
738 * Recalling truncate_inode_pages_range and unmap_mapping_range
739 * every time for punch_hole (which never got a chance to clear
740 * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive,
741 * yet hardly ever necessary: try to optimize them out later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 */
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800743 truncate_inode_pages_range(inode->i_mapping, start, end);
Hugh Dickins16a10012007-03-29 01:20:37 -0700744 if (punch_hole)
745 unmap_mapping_range(inode->i_mapping, start,
746 end - start, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 }
748
749 spin_lock(&info->lock);
750 info->flags &= ~SHMEM_TRUNCATE;
751 info->swapped -= nr_swaps_freed;
752 if (nr_pages_to_free)
753 shmem_free_blocks(inode, nr_pages_to_free);
754 shmem_recalc_inode(inode);
755 spin_unlock(&info->lock);
756
757 /*
758 * Empty swap vector directory pages to be freed?
759 */
760 if (!list_empty(&pages_to_free)) {
761 pages_to_free.prev->next = NULL;
762 shmem_free_pages(pages_to_free.next);
763 }
764}
765
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800766static void shmem_truncate(struct inode *inode)
767{
768 shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
769}
770
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
772{
773 struct inode *inode = dentry->d_inode;
774 struct page *page = NULL;
775 int error;
776
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700777 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 if (attr->ia_size < inode->i_size) {
779 /*
780 * If truncating down to a partial page, then
781 * if that page is already allocated, hold it
782 * in memory until the truncation is over, so
783 * truncate_partial_page cannnot miss it were
784 * it assigned to swap.
785 */
786 if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
787 (void) shmem_getpage(inode,
788 attr->ia_size>>PAGE_CACHE_SHIFT,
789 &page, SGP_READ, NULL);
Hugh Dickinsd3602442008-02-04 22:28:44 -0800790 if (page)
791 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 }
793 /*
794 * Reset SHMEM_PAGEIN flag so that shmem_truncate can
795 * detect if any pages might have been added to cache
796 * after truncate_inode_pages. But we needn't bother
797 * if it's being fully truncated to zero-length: the
798 * nrpages check is efficient enough in that case.
799 */
800 if (attr->ia_size) {
801 struct shmem_inode_info *info = SHMEM_I(inode);
802 spin_lock(&info->lock);
803 info->flags &= ~SHMEM_PAGEIN;
804 spin_unlock(&info->lock);
805 }
806 }
807 }
808
809 error = inode_change_ok(inode, attr);
810 if (!error)
811 error = inode_setattr(inode, attr);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700812#ifdef CONFIG_TMPFS_POSIX_ACL
813 if (!error && (attr->ia_valid & ATTR_MODE))
814 error = generic_acl_chmod(inode, &shmem_acl_ops);
815#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 if (page)
817 page_cache_release(page);
818 return error;
819}
820
821static void shmem_delete_inode(struct inode *inode)
822{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 struct shmem_inode_info *info = SHMEM_I(inode);
824
825 if (inode->i_op->truncate == shmem_truncate) {
Mark Fashehfef26652005-09-09 13:01:31 -0700826 truncate_inode_pages(inode->i_mapping, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 shmem_unacct_size(info->flags, inode->i_size);
828 inode->i_size = 0;
829 shmem_truncate(inode);
830 if (!list_empty(&info->swaplist)) {
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800831 mutex_lock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 list_del_init(&info->swaplist);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800833 mutex_unlock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 }
835 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700836 BUG_ON(inode->i_blocks);
Pavel Emelyanov5b04c682008-02-04 22:28:47 -0800837 shmem_free_inode(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 clear_inode(inode);
839}
840
841static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
842{
843 swp_entry_t *ptr;
844
845 for (ptr = dir; ptr < edir; ptr++) {
846 if (ptr->val == entry.val)
847 return ptr - dir;
848 }
849 return -1;
850}
851
852static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
853{
854 struct inode *inode;
855 unsigned long idx;
856 unsigned long size;
857 unsigned long limit;
858 unsigned long stage;
859 struct page **dir;
860 struct page *subdir;
861 swp_entry_t *ptr;
862 int offset;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800863 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864
865 idx = 0;
866 ptr = info->i_direct;
867 spin_lock(&info->lock);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800868 if (!info->swapped) {
869 list_del_init(&info->swaplist);
870 goto lost2;
871 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 limit = info->next_index;
873 size = limit;
874 if (size > SHMEM_NR_DIRECT)
875 size = SHMEM_NR_DIRECT;
876 offset = shmem_find_swp(entry, ptr, ptr+size);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800877 if (offset >= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 goto found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 if (!info->i_indirect)
880 goto lost2;
881
882 dir = shmem_dir_map(info->i_indirect);
883 stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
884
885 for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
886 if (unlikely(idx == stage)) {
887 shmem_dir_unmap(dir-1);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800888 if (cond_resched_lock(&info->lock)) {
889 /* check it has not been truncated */
890 if (limit > info->next_index) {
891 limit = info->next_index;
892 if (idx >= limit)
893 goto lost2;
894 }
895 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 dir = shmem_dir_map(info->i_indirect) +
897 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
898 while (!*dir) {
899 dir++;
900 idx += ENTRIES_PER_PAGEPAGE;
901 if (idx >= limit)
902 goto lost1;
903 }
904 stage = idx + ENTRIES_PER_PAGEPAGE;
905 subdir = *dir;
906 shmem_dir_unmap(dir);
907 dir = shmem_dir_map(subdir);
908 }
909 subdir = *dir;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700910 if (subdir && page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 ptr = shmem_swp_map(subdir);
912 size = limit - idx;
913 if (size > ENTRIES_PER_PAGE)
914 size = ENTRIES_PER_PAGE;
915 offset = shmem_find_swp(entry, ptr, ptr+size);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800916 shmem_swp_unmap(ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 if (offset >= 0) {
918 shmem_dir_unmap(dir);
919 goto found;
920 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 }
922 }
923lost1:
924 shmem_dir_unmap(dir-1);
925lost2:
926 spin_unlock(&info->lock);
927 return 0;
928found:
929 idx += offset;
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800930 inode = igrab(&info->vfs_inode);
931 spin_unlock(&info->lock);
932
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800933 /*
934 * Move _head_ to start search for next from here.
935 * But be careful: shmem_delete_inode checks list_empty without taking
936 * mutex, and there's an instant in list_move_tail when info->swaplist
937 * would appear empty, if it were the only one on shmem_swaplist. We
938 * could avoid doing it if inode NULL; or use this minor optimization.
939 */
940 if (shmem_swaplist.next != &info->swaplist)
941 list_move_tail(&shmem_swaplist, &info->swaplist);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800942 mutex_unlock(&shmem_swaplist_mutex);
943
944 error = 1;
945 if (!inode)
946 goto out;
KAMEZAWA Hiroyukid13d1442009-01-07 18:07:56 -0800947 /*
KAMEZAWA Hiroyukib5a84312009-01-07 18:08:35 -0800948 * Charge page using GFP_KERNEL while we can wait.
949 * Charged back to the user(not to caller) when swap account is used.
950 * add_to_page_cache() will be called with GFP_NOWAIT.
KAMEZAWA Hiroyukid13d1442009-01-07 18:07:56 -0800951 */
Hugh Dickins82369552008-02-07 00:14:22 -0800952 error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800953 if (error)
954 goto out;
Hugh Dickins82369552008-02-07 00:14:22 -0800955 error = radix_tree_preload(GFP_KERNEL);
KAMEZAWA Hiroyuki69029cd2008-07-25 01:47:14 -0700956 if (error) {
957 mem_cgroup_uncharge_cache_page(page);
958 goto out;
959 }
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800960 error = 1;
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800961
962 spin_lock(&info->lock);
963 ptr = shmem_swp_entry(info, idx, NULL);
KAMEZAWA Hiroyuki69029cd2008-07-25 01:47:14 -0700964 if (ptr && ptr->val == entry.val) {
Nick Piggine2867812008-07-25 19:45:30 -0700965 error = add_to_page_cache_locked(page, inode->i_mapping,
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800966 idx, GFP_NOWAIT);
KAMEZAWA Hiroyuki69029cd2008-07-25 01:47:14 -0700967 /* does mem_cgroup_uncharge_cache_page on error */
968 } else /* we must compensate for our precharge above */
969 mem_cgroup_uncharge_cache_page(page);
970
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800971 if (error == -EEXIST) {
972 struct page *filepage = find_get_page(inode->i_mapping, idx);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800973 error = 1;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800974 if (filepage) {
975 /*
976 * There might be a more uptodate page coming down
977 * from a stacked writepage: forget our swappage if so.
978 */
979 if (PageUptodate(filepage))
980 error = 0;
981 page_cache_release(filepage);
982 }
983 }
984 if (!error) {
Hugh Dickins73b12622008-02-04 22:28:50 -0800985 delete_from_swap_cache(page);
986 set_page_dirty(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 info->flags |= SHMEM_PAGEIN;
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800988 shmem_swp_set(info, ptr, 0);
989 swap_free(entry);
990 error = 1; /* not an error, but entry was found */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 }
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800992 if (ptr)
993 shmem_swp_unmap(ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 spin_unlock(&info->lock);
Hugh Dickinsb409f9f2008-02-04 22:28:54 -0800995 radix_tree_preload_end();
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800996out:
997 unlock_page(page);
998 page_cache_release(page);
999 iput(inode); /* allows for NULL */
1000 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001}
1002
1003/*
1004 * shmem_unuse() search for an eventually swapped out shmem page.
1005 */
1006int shmem_unuse(swp_entry_t entry, struct page *page)
1007{
1008 struct list_head *p, *next;
1009 struct shmem_inode_info *info;
1010 int found = 0;
1011
Hugh Dickinscb5f7b92008-02-04 22:28:52 -08001012 mutex_lock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 list_for_each_safe(p, next, &shmem_swaplist) {
1014 info = list_entry(p, struct shmem_inode_info, swaplist);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -08001015 found = shmem_unuse_inode(info, entry, page);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -08001016 cond_resched();
Hugh Dickins2e0e26c2008-02-04 22:28:53 -08001017 if (found)
1018 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 }
Hugh Dickinscb5f7b92008-02-04 22:28:52 -08001020 mutex_unlock(&shmem_swaplist_mutex);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -08001021out: return found; /* 0 or 1 or -ENOMEM */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022}
1023
1024/*
1025 * Move the page from the page cache to the swap cache.
1026 */
1027static int shmem_writepage(struct page *page, struct writeback_control *wbc)
1028{
1029 struct shmem_inode_info *info;
1030 swp_entry_t *entry, swap;
1031 struct address_space *mapping;
1032 unsigned long index;
1033 struct inode *inode;
1034
1035 BUG_ON(!PageLocked(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 mapping = page->mapping;
1037 index = page->index;
1038 inode = mapping->host;
1039 info = SHMEM_I(inode);
1040 if (info->flags & VM_LOCKED)
1041 goto redirty;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001042 if (!total_swap_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 goto redirty;
1044
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001045 /*
1046 * shmem_backing_dev_info's capabilities prevent regular writeback or
1047 * sync from ever calling shmem_writepage; but a stacking filesystem
1048 * may use the ->writepage of its underlying filesystem, in which case
1049 * tmpfs should write out to swap only in response to memory pressure,
1050 * and not for pdflush or sync. However, in those cases, we do still
1051 * want to check if there's a redundant swappage to be discarded.
1052 */
1053 if (wbc->for_reclaim)
1054 swap = get_swap_page();
1055 else
1056 swap.val = 0;
1057
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 spin_lock(&info->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059 if (index >= info->next_index) {
1060 BUG_ON(!(info->flags & SHMEM_TRUNCATE));
1061 goto unlock;
1062 }
1063 entry = shmem_swp_entry(info, index, NULL);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001064 if (entry->val) {
1065 /*
1066 * The more uptodate page coming down from a stacked
1067 * writepage should replace our old swappage.
1068 */
1069 free_swap_and_cache(*entry);
1070 shmem_swp_set(info, entry, 0);
1071 }
1072 shmem_recalc_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001074 if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
Hugh Dickins73b12622008-02-04 22:28:50 -08001075 remove_from_page_cache(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076 shmem_swp_set(info, entry, swap.val);
1077 shmem_swp_unmap(entry);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -08001078 if (list_empty(&info->swaplist))
1079 inode = igrab(inode);
1080 else
1081 inode = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 spin_unlock(&info->lock);
Hugh Dickins73b12622008-02-04 22:28:50 -08001083 swap_duplicate(swap);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001084 BUG_ON(page_mapped(page));
Hugh Dickins73b12622008-02-04 22:28:50 -08001085 page_cache_release(page); /* pagecache ref */
Hugh Dickins9fab5612009-03-31 15:23:33 -07001086 swap_writepage(page, wbc);
Hugh Dickins1b1b32f2008-02-04 22:28:55 -08001087 if (inode) {
1088 mutex_lock(&shmem_swaplist_mutex);
1089 /* move instead of add in case we're racing */
1090 list_move_tail(&info->swaplist, &shmem_swaplist);
1091 mutex_unlock(&shmem_swaplist_mutex);
1092 iput(inode);
1093 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 return 0;
1095 }
1096
1097 shmem_swp_unmap(entry);
1098unlock:
1099 spin_unlock(&info->lock);
KAMEZAWA Hiroyukicb4b86b2009-06-16 15:32:52 -07001100 swapcache_free(swap, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101redirty:
1102 set_page_dirty(page);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -08001103 if (wbc->for_reclaim)
1104 return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */
1105 unlock_page(page);
1106 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107}
1108
1109#ifdef CONFIG_NUMA
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001110#ifdef CONFIG_TMPFS
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001111static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001112{
Lee Schermerhorn095f1fc2008-04-28 02:13:23 -07001113 char buffer[64];
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001114
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001115 if (!mpol || mpol->mode == MPOL_DEFAULT)
Lee Schermerhorn095f1fc2008-04-28 02:13:23 -07001116 return; /* show nothing */
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001117
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001118 mpol_to_str(buffer, sizeof(buffer), mpol, 1);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001119
Lee Schermerhorn095f1fc2008-04-28 02:13:23 -07001120 seq_printf(seq, ",mpol=%s", buffer);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001121}
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001122
1123static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1124{
1125 struct mempolicy *mpol = NULL;
1126 if (sbinfo->mpol) {
1127 spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */
1128 mpol = sbinfo->mpol;
1129 mpol_get(mpol);
1130 spin_unlock(&sbinfo->stat_lock);
1131 }
1132 return mpol;
1133}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001134#endif /* CONFIG_TMPFS */
1135
Hugh Dickins02098fe2008-02-04 22:28:42 -08001136static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
1137 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138{
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -07001139 struct mempolicy mpol, *spol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140 struct vm_area_struct pvma;
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001141 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -07001143 spol = mpol_cond_copy(&mpol,
1144 mpol_shared_policy_lookup(&info->policy, idx));
1145
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 /* Create a pseudo vma that just contains the policy */
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001147 pvma.vm_start = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 pvma.vm_pgoff = idx;
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001149 pvma.vm_ops = NULL;
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -07001150 pvma.vm_policy = spol;
Hugh Dickins02098fe2008-02-04 22:28:42 -08001151 page = swapin_readahead(entry, gfp, &pvma, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 return page;
1153}
1154
Hugh Dickins02098fe2008-02-04 22:28:42 -08001155static struct page *shmem_alloc_page(gfp_t gfp,
1156 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157{
1158 struct vm_area_struct pvma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001160 /* Create a pseudo vma that just contains the policy */
1161 pvma.vm_start = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 pvma.vm_pgoff = idx;
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -08001163 pvma.vm_ops = NULL;
1164 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -07001165
1166 /*
1167 * alloc_page_vma() will drop the shared policy reference
1168 */
1169 return alloc_page_vma(gfp, &pvma, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001171#else /* !CONFIG_NUMA */
1172#ifdef CONFIG_TMPFS
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001173static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p)
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001174{
1175}
1176#endif /* CONFIG_TMPFS */
1177
Hugh Dickins02098fe2008-02-04 22:28:42 -08001178static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
1179 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180{
Hugh Dickins02098fe2008-02-04 22:28:42 -08001181 return swapin_readahead(entry, gfp, NULL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182}
1183
Hugh Dickins02098fe2008-02-04 22:28:42 -08001184static inline struct page *shmem_alloc_page(gfp_t gfp,
1185 struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186{
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001187 return alloc_page(gfp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08001189#endif /* CONFIG_NUMA */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001191#if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
1192static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1193{
1194 return NULL;
1195}
1196#endif
1197
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198/*
1199 * shmem_getpage - either get the page from swap or allocate a new one
1200 *
1201 * If we allocate a new one we do not mark it dirty. That's up to the
1202 * vm. If we swap it in we mark it dirty since we also free the swap
1203 * entry since a page cannot live in both the swap and page cache
1204 */
1205static int shmem_getpage(struct inode *inode, unsigned long idx,
1206 struct page **pagep, enum sgp_type sgp, int *type)
1207{
1208 struct address_space *mapping = inode->i_mapping;
1209 struct shmem_inode_info *info = SHMEM_I(inode);
1210 struct shmem_sb_info *sbinfo;
1211 struct page *filepage = *pagep;
1212 struct page *swappage;
1213 swp_entry_t *entry;
1214 swp_entry_t swap;
Hugh Dickins02098fe2008-02-04 22:28:42 -08001215 gfp_t gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216 int error;
1217
1218 if (idx >= SHMEM_MAX_INDEX)
1219 return -EFBIG;
Nick Piggin54cb8822007-07-19 01:46:59 -07001220
1221 if (type)
Nick Piggin83c54072007-07-19 01:47:05 -07001222 *type = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07001223
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 /*
1225 * Normally, filepage is NULL on entry, and either found
1226 * uptodate immediately, or allocated and zeroed, or read
1227 * in under swappage, which is then assigned to filepage.
Hugh Dickins5402b972008-02-04 22:28:44 -08001228 * But shmem_readpage (required for splice) passes in a locked
Hugh Dickinsae9764162007-06-04 10:00:39 +02001229 * filepage, which may be found not uptodate by other callers
1230 * too, and may need to be copied from the swappage read in.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 */
1232repeat:
1233 if (!filepage)
1234 filepage = find_lock_page(mapping, idx);
1235 if (filepage && PageUptodate(filepage))
1236 goto done;
1237 error = 0;
Hugh Dickins02098fe2008-02-04 22:28:42 -08001238 gfp = mapping_gfp_mask(mapping);
Hugh Dickinsb409f9f2008-02-04 22:28:54 -08001239 if (!filepage) {
1240 /*
1241 * Try to preload while we can wait, to not make a habit of
1242 * draining atomic reserves; but don't latch on to this cpu.
1243 */
1244 error = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
1245 if (error)
1246 goto failed;
1247 radix_tree_preload_end();
1248 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249
1250 spin_lock(&info->lock);
1251 shmem_recalc_inode(inode);
1252 entry = shmem_swp_alloc(info, idx, sgp);
1253 if (IS_ERR(entry)) {
1254 spin_unlock(&info->lock);
1255 error = PTR_ERR(entry);
1256 goto failed;
1257 }
1258 swap = *entry;
1259
1260 if (swap.val) {
1261 /* Look it up and read it in.. */
1262 swappage = lookup_swap_cache(swap);
1263 if (!swappage) {
1264 shmem_swp_unmap(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 /* here we actually do the io */
Nick Piggin83c54072007-07-19 01:47:05 -07001266 if (type && !(*type & VM_FAULT_MAJOR)) {
Christoph Lameterf8891e52006-06-30 01:55:45 -07001267 __count_vm_event(PGMAJFAULT);
Nick Piggin83c54072007-07-19 01:47:05 -07001268 *type |= VM_FAULT_MAJOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 }
Christoph Lameterf8891e52006-06-30 01:55:45 -07001270 spin_unlock(&info->lock);
Hugh Dickins02098fe2008-02-04 22:28:42 -08001271 swappage = shmem_swapin(swap, gfp, info, idx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272 if (!swappage) {
1273 spin_lock(&info->lock);
1274 entry = shmem_swp_alloc(info, idx, sgp);
1275 if (IS_ERR(entry))
1276 error = PTR_ERR(entry);
1277 else {
1278 if (entry->val == swap.val)
1279 error = -ENOMEM;
1280 shmem_swp_unmap(entry);
1281 }
1282 spin_unlock(&info->lock);
1283 if (error)
1284 goto failed;
1285 goto repeat;
1286 }
1287 wait_on_page_locked(swappage);
1288 page_cache_release(swappage);
1289 goto repeat;
1290 }
1291
1292 /* We have to do this with page locked to prevent races */
Nick Piggin529ae9a2008-08-02 12:01:03 +02001293 if (!trylock_page(swappage)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 shmem_swp_unmap(entry);
1295 spin_unlock(&info->lock);
1296 wait_on_page_locked(swappage);
1297 page_cache_release(swappage);
1298 goto repeat;
1299 }
1300 if (PageWriteback(swappage)) {
1301 shmem_swp_unmap(entry);
1302 spin_unlock(&info->lock);
1303 wait_on_page_writeback(swappage);
1304 unlock_page(swappage);
1305 page_cache_release(swappage);
1306 goto repeat;
1307 }
1308 if (!PageUptodate(swappage)) {
1309 shmem_swp_unmap(entry);
1310 spin_unlock(&info->lock);
1311 unlock_page(swappage);
1312 page_cache_release(swappage);
1313 error = -EIO;
1314 goto failed;
1315 }
1316
1317 if (filepage) {
1318 shmem_swp_set(info, entry, 0);
1319 shmem_swp_unmap(entry);
1320 delete_from_swap_cache(swappage);
1321 spin_unlock(&info->lock);
1322 copy_highpage(filepage, swappage);
1323 unlock_page(swappage);
1324 page_cache_release(swappage);
1325 flush_dcache_page(filepage);
1326 SetPageUptodate(filepage);
1327 set_page_dirty(filepage);
1328 swap_free(swap);
Nick Piggine2867812008-07-25 19:45:30 -07001329 } else if (!(error = add_to_page_cache_locked(swappage, mapping,
1330 idx, GFP_NOWAIT))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 info->flags |= SHMEM_PAGEIN;
1332 shmem_swp_set(info, entry, 0);
1333 shmem_swp_unmap(entry);
Hugh Dickins73b12622008-02-04 22:28:50 -08001334 delete_from_swap_cache(swappage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 spin_unlock(&info->lock);
1336 filepage = swappage;
Hugh Dickins73b12622008-02-04 22:28:50 -08001337 set_page_dirty(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 swap_free(swap);
1339 } else {
1340 shmem_swp_unmap(entry);
1341 spin_unlock(&info->lock);
Hugh Dickins82369552008-02-07 00:14:22 -08001342 if (error == -ENOMEM) {
Daisuke Nishimuraae3abae2009-04-30 15:08:19 -07001343 /*
1344 * reclaim from proper memory cgroup and
1345 * call memcg's OOM if needed.
1346 */
1347 error = mem_cgroup_shmem_charge_fallback(
1348 swappage,
KAMEZAWA Hiroyukib5a84312009-01-07 18:08:35 -08001349 current->mm,
KAMEZAWA Hiroyukic9b0ed52008-07-25 01:47:15 -07001350 gfp);
KAMEZAWA Hiroyukib5a84312009-01-07 18:08:35 -08001351 if (error) {
1352 unlock_page(swappage);
1353 page_cache_release(swappage);
Hugh Dickins82369552008-02-07 00:14:22 -08001354 goto failed;
KAMEZAWA Hiroyukib5a84312009-01-07 18:08:35 -08001355 }
Hugh Dickins82369552008-02-07 00:14:22 -08001356 }
KAMEZAWA Hiroyukib5a84312009-01-07 18:08:35 -08001357 unlock_page(swappage);
1358 page_cache_release(swappage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 goto repeat;
1360 }
1361 } else if (sgp == SGP_READ && !filepage) {
1362 shmem_swp_unmap(entry);
1363 filepage = find_get_page(mapping, idx);
1364 if (filepage &&
Nick Piggin529ae9a2008-08-02 12:01:03 +02001365 (!PageUptodate(filepage) || !trylock_page(filepage))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 spin_unlock(&info->lock);
1367 wait_on_page_locked(filepage);
1368 page_cache_release(filepage);
1369 filepage = NULL;
1370 goto repeat;
1371 }
1372 spin_unlock(&info->lock);
1373 } else {
1374 shmem_swp_unmap(entry);
1375 sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001376 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 spin_lock(&sbinfo->stat_lock);
1378 if (sbinfo->free_blocks == 0 ||
1379 shmem_acct_block(info->flags)) {
1380 spin_unlock(&sbinfo->stat_lock);
1381 spin_unlock(&info->lock);
1382 error = -ENOSPC;
1383 goto failed;
1384 }
1385 sbinfo->free_blocks--;
1386 inode->i_blocks += BLOCKS_PER_PAGE;
1387 spin_unlock(&sbinfo->stat_lock);
1388 } else if (shmem_acct_block(info->flags)) {
1389 spin_unlock(&info->lock);
1390 error = -ENOSPC;
1391 goto failed;
1392 }
1393
1394 if (!filepage) {
KAMEZAWA Hiroyuki69029cd2008-07-25 01:47:14 -07001395 int ret;
1396
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 spin_unlock(&info->lock);
Hugh Dickins02098fe2008-02-04 22:28:42 -08001398 filepage = shmem_alloc_page(gfp, info, idx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 if (!filepage) {
1400 shmem_unacct_blocks(info->flags, 1);
1401 shmem_free_blocks(inode, 1);
1402 error = -ENOMEM;
1403 goto failed;
1404 }
Rik van Rielb2e18532008-10-18 20:26:30 -07001405 SetPageSwapBacked(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001406
Hugh Dickins82369552008-02-07 00:14:22 -08001407 /* Precharge page while we can wait, compensate after */
1408 error = mem_cgroup_cache_charge(filepage, current->mm,
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08001409 GFP_KERNEL);
Hugh Dickins82369552008-02-07 00:14:22 -08001410 if (error) {
1411 page_cache_release(filepage);
1412 shmem_unacct_blocks(info->flags, 1);
1413 shmem_free_blocks(inode, 1);
1414 filepage = NULL;
1415 goto failed;
1416 }
1417
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 spin_lock(&info->lock);
1419 entry = shmem_swp_alloc(info, idx, sgp);
1420 if (IS_ERR(entry))
1421 error = PTR_ERR(entry);
1422 else {
1423 swap = *entry;
1424 shmem_swp_unmap(entry);
1425 }
KAMEZAWA Hiroyuki69029cd2008-07-25 01:47:14 -07001426 ret = error || swap.val;
1427 if (ret)
1428 mem_cgroup_uncharge_cache_page(filepage);
1429 else
1430 ret = add_to_page_cache_lru(filepage, mapping,
1431 idx, GFP_NOWAIT);
1432 /*
1433 * At add_to_page_cache_lru() failure, uncharge will
1434 * be done automatically.
1435 */
1436 if (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437 spin_unlock(&info->lock);
1438 page_cache_release(filepage);
1439 shmem_unacct_blocks(info->flags, 1);
1440 shmem_free_blocks(inode, 1);
1441 filepage = NULL;
1442 if (error)
1443 goto failed;
1444 goto repeat;
1445 }
1446 info->flags |= SHMEM_PAGEIN;
1447 }
1448
1449 info->alloced++;
1450 spin_unlock(&info->lock);
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001451 clear_highpage(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452 flush_dcache_page(filepage);
1453 SetPageUptodate(filepage);
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001454 if (sgp == SGP_DIRTY)
1455 set_page_dirty(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456 }
1457done:
Hugh Dickinsd3602442008-02-04 22:28:44 -08001458 *pagep = filepage;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 return 0;
1460
1461failed:
1462 if (*pagep != filepage) {
1463 unlock_page(filepage);
1464 page_cache_release(filepage);
1465 }
1466 return error;
1467}
1468
Nick Piggind0217ac2007-07-19 01:47:03 -07001469static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001471 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 int error;
Nick Piggind0217ac2007-07-19 01:47:03 -07001473 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474
Nick Piggind0217ac2007-07-19 01:47:03 -07001475 if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
1476 return VM_FAULT_SIGBUS;
Nick Piggind00806b2007-07-19 01:46:57 -07001477
Hugh Dickins27d54b32008-02-04 22:28:43 -08001478 error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
Nick Piggind0217ac2007-07-19 01:47:03 -07001479 if (error)
1480 return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481
Nick Piggin83c54072007-07-19 01:47:05 -07001482 return ret | VM_FAULT_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483}
1484
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485#ifdef CONFIG_NUMA
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001486static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001488 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
1490}
1491
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001492static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
1493 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001495 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 unsigned long idx;
1497
1498 idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
1499 return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
1500}
1501#endif
1502
1503int shmem_lock(struct file *file, int lock, struct user_struct *user)
1504{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001505 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506 struct shmem_inode_info *info = SHMEM_I(inode);
1507 int retval = -ENOMEM;
1508
1509 spin_lock(&info->lock);
1510 if (lock && !(info->flags & VM_LOCKED)) {
1511 if (!user_shm_lock(inode->i_size, user))
1512 goto out_nomem;
1513 info->flags |= VM_LOCKED;
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -07001514 mapping_set_unevictable(file->f_mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001515 }
1516 if (!lock && (info->flags & VM_LOCKED) && user) {
1517 user_shm_unlock(inode->i_size, user);
1518 info->flags &= ~VM_LOCKED;
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -07001519 mapping_clear_unevictable(file->f_mapping);
1520 scan_mapping_unevictable_pages(file->f_mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521 }
1522 retval = 0;
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -07001523
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524out_nomem:
1525 spin_unlock(&info->lock);
1526 return retval;
1527}
1528
Adrian Bunk9b83a6a2007-02-28 20:11:03 -08001529static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530{
1531 file_accessed(file);
1532 vma->vm_ops = &shmem_vm_ops;
Nick Piggind0217ac2007-07-19 01:47:03 -07001533 vma->vm_flags |= VM_CAN_NONLINEAR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534 return 0;
1535}
1536
Hugh Dickins0b0a0802009-02-24 20:51:52 +00001537static struct inode *shmem_get_inode(struct super_block *sb, int mode,
1538 dev_t dev, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539{
1540 struct inode *inode;
1541 struct shmem_inode_info *info;
1542 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
1543
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001544 if (shmem_reserve_inode(sb))
1545 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546
1547 inode = new_inode(sb);
1548 if (inode) {
1549 inode->i_mode = mode;
David Howells76aac0e2008-11-14 10:39:12 +11001550 inode->i_uid = current_fsuid();
1551 inode->i_gid = current_fsgid();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552 inode->i_blocks = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553 inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
1554 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
David M. Grimes91828a42006-10-17 00:09:45 -07001555 inode->i_generation = get_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 info = SHMEM_I(inode);
1557 memset(info, 0, (char *)inode - (char *)info);
1558 spin_lock_init(&info->lock);
Hugh Dickins0b0a0802009-02-24 20:51:52 +00001559 info->flags = flags & VM_NORESERVE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001560 INIT_LIST_HEAD(&info->swaplist);
Al Viro72c04902009-06-24 16:58:48 -04001561 cache_no_acl(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562
1563 switch (mode & S_IFMT) {
1564 default:
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001565 inode->i_op = &shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 init_special_inode(inode, mode, dev);
1567 break;
1568 case S_IFREG:
Hugh Dickins14fcc232008-07-28 15:46:19 -07001569 inode->i_mapping->a_ops = &shmem_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 inode->i_op = &shmem_inode_operations;
1571 inode->i_fop = &shmem_file_operations;
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001572 mpol_shared_policy_init(&info->policy,
1573 shmem_get_sbmpol(sbinfo));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 break;
1575 case S_IFDIR:
Dave Hansend8c76e62006-09-30 23:29:04 -07001576 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577 /* Some things misbehave if size == 0 on a directory */
1578 inode->i_size = 2 * BOGO_DIRENT_SIZE;
1579 inode->i_op = &shmem_dir_inode_operations;
1580 inode->i_fop = &simple_dir_operations;
1581 break;
1582 case S_IFLNK:
1583 /*
1584 * Must not load anything in the rbtree,
1585 * mpol_free_shared_policy will not be called.
1586 */
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001587 mpol_shared_policy_init(&info->policy, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588 break;
1589 }
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001590 } else
1591 shmem_free_inode(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592 return inode;
1593}
1594
1595#ifdef CONFIG_TMPFS
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001596static const struct inode_operations shmem_symlink_inode_operations;
1597static const struct inode_operations shmem_symlink_inline_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001598
1599/*
Nick Piggin800d15a2007-10-16 01:25:03 -07001600 * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin;
Hugh Dickinsae9764162007-06-04 10:00:39 +02001601 * but providing them allows a tmpfs file to be used for splice, sendfile, and
1602 * below the loop driver, in the generic fashion that many filesystems support.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001603 */
Hugh Dickinsae9764162007-06-04 10:00:39 +02001604static int shmem_readpage(struct file *file, struct page *page)
1605{
1606 struct inode *inode = page->mapping->host;
1607 int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL);
1608 unlock_page(page);
1609 return error;
1610}
1611
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612static int
Nick Piggin800d15a2007-10-16 01:25:03 -07001613shmem_write_begin(struct file *file, struct address_space *mapping,
1614 loff_t pos, unsigned len, unsigned flags,
1615 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616{
Nick Piggin800d15a2007-10-16 01:25:03 -07001617 struct inode *inode = mapping->host;
1618 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1619 *pagep = NULL;
1620 return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL);
1621}
1622
1623static int
1624shmem_write_end(struct file *file, struct address_space *mapping,
1625 loff_t pos, unsigned len, unsigned copied,
1626 struct page *page, void *fsdata)
1627{
1628 struct inode *inode = mapping->host;
1629
Hugh Dickinsd3602442008-02-04 22:28:44 -08001630 if (pos + copied > inode->i_size)
1631 i_size_write(inode, pos + copied);
1632
1633 unlock_page(page);
Nick Piggin800d15a2007-10-16 01:25:03 -07001634 set_page_dirty(page);
1635 page_cache_release(page);
1636
Nick Piggin800d15a2007-10-16 01:25:03 -07001637 return copied;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638}
1639
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
1641{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001642 struct inode *inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001643 struct address_space *mapping = inode->i_mapping;
1644 unsigned long index, offset;
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001645 enum sgp_type sgp = SGP_READ;
1646
1647 /*
1648 * Might this read be for a stacking filesystem? Then when reading
1649 * holes of a sparse file, we actually need to allocate those pages,
1650 * and even mark them dirty, so it cannot exceed the max_blocks limit.
1651 */
1652 if (segment_eq(get_fs(), KERNEL_DS))
1653 sgp = SGP_DIRTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654
1655 index = *ppos >> PAGE_CACHE_SHIFT;
1656 offset = *ppos & ~PAGE_CACHE_MASK;
1657
1658 for (;;) {
1659 struct page *page = NULL;
1660 unsigned long end_index, nr, ret;
1661 loff_t i_size = i_size_read(inode);
1662
1663 end_index = i_size >> PAGE_CACHE_SHIFT;
1664 if (index > end_index)
1665 break;
1666 if (index == end_index) {
1667 nr = i_size & ~PAGE_CACHE_MASK;
1668 if (nr <= offset)
1669 break;
1670 }
1671
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001672 desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673 if (desc->error) {
1674 if (desc->error == -EINVAL)
1675 desc->error = 0;
1676 break;
1677 }
Hugh Dickinsd3602442008-02-04 22:28:44 -08001678 if (page)
1679 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680
1681 /*
1682 * We must evaluate after, since reads (unlike writes)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001683 * are called without i_mutex protection against truncate
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684 */
1685 nr = PAGE_CACHE_SIZE;
1686 i_size = i_size_read(inode);
1687 end_index = i_size >> PAGE_CACHE_SHIFT;
1688 if (index == end_index) {
1689 nr = i_size & ~PAGE_CACHE_MASK;
1690 if (nr <= offset) {
1691 if (page)
1692 page_cache_release(page);
1693 break;
1694 }
1695 }
1696 nr -= offset;
1697
1698 if (page) {
1699 /*
1700 * If users can be writing to this page using arbitrary
1701 * virtual addresses, take care about potential aliasing
1702 * before reading the page on the kernel side.
1703 */
1704 if (mapping_writably_mapped(mapping))
1705 flush_dcache_page(page);
1706 /*
1707 * Mark the page accessed if we read the beginning.
1708 */
1709 if (!offset)
1710 mark_page_accessed(page);
Nick Pigginb5810032005-10-29 18:16:12 -07001711 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712 page = ZERO_PAGE(0);
Nick Pigginb5810032005-10-29 18:16:12 -07001713 page_cache_get(page);
1714 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715
1716 /*
1717 * Ok, we have the page, and it's up-to-date, so
1718 * now we can copy it to user space...
1719 *
1720 * The actor routine returns how many bytes were actually used..
1721 * NOTE! This may not be the same as how much of a user buffer
1722 * we filled up (we may be padding etc), so we can only update
1723 * "pos" here (the actor routine has to update the user buffer
1724 * pointers and the remaining count).
1725 */
1726 ret = actor(desc, page, offset, nr);
1727 offset += ret;
1728 index += offset >> PAGE_CACHE_SHIFT;
1729 offset &= ~PAGE_CACHE_MASK;
1730
1731 page_cache_release(page);
1732 if (ret != nr || !desc->count)
1733 break;
1734
1735 cond_resched();
1736 }
1737
1738 *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
1739 file_accessed(filp);
1740}
1741
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001742static ssize_t shmem_file_aio_read(struct kiocb *iocb,
1743 const struct iovec *iov, unsigned long nr_segs, loff_t pos)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001744{
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001745 struct file *filp = iocb->ki_filp;
1746 ssize_t retval;
1747 unsigned long seg;
1748 size_t count;
1749 loff_t *ppos = &iocb->ki_pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001751 retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
1752 if (retval)
1753 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001755 for (seg = 0; seg < nr_segs; seg++) {
1756 read_descriptor_t desc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001758 desc.written = 0;
1759 desc.arg.buf = iov[seg].iov_base;
1760 desc.count = iov[seg].iov_len;
1761 if (desc.count == 0)
1762 continue;
1763 desc.error = 0;
1764 do_shmem_file_read(filp, ppos, &desc, file_read_actor);
1765 retval += desc.written;
1766 if (desc.error) {
1767 retval = retval ?: desc.error;
1768 break;
1769 }
1770 if (desc.count > 0)
1771 break;
1772 }
1773 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774}
1775
David Howells726c3342006-06-23 02:02:58 -07001776static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777{
David Howells726c3342006-06-23 02:02:58 -07001778 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779
1780 buf->f_type = TMPFS_MAGIC;
1781 buf->f_bsize = PAGE_CACHE_SIZE;
1782 buf->f_namelen = NAME_MAX;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001783 spin_lock(&sbinfo->stat_lock);
1784 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785 buf->f_blocks = sbinfo->max_blocks;
1786 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001787 }
1788 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 buf->f_files = sbinfo->max_inodes;
1790 buf->f_ffree = sbinfo->free_inodes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 }
1792 /* else leave those fields 0 like simple_statfs */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001793 spin_unlock(&sbinfo->stat_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 return 0;
1795}
1796
1797/*
1798 * File creation. Allocate an inode, and we're done..
1799 */
1800static int
1801shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1802{
Hugh Dickins0b0a0802009-02-24 20:51:52 +00001803 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804 int error = -ENOSPC;
1805
Hugh Dickins0b0a0802009-02-24 20:51:52 +00001806 inode = shmem_get_inode(dir->i_sb, mode, dev, VM_NORESERVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807 if (inode) {
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001808 error = security_inode_init_security(inode, dir, NULL, NULL,
1809 NULL);
1810 if (error) {
1811 if (error != -EOPNOTSUPP) {
1812 iput(inode);
1813 return error;
1814 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001815 }
1816 error = shmem_acl_init(inode, dir);
1817 if (error) {
1818 iput(inode);
1819 return error;
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001820 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 if (dir->i_mode & S_ISGID) {
1822 inode->i_gid = dir->i_gid;
1823 if (S_ISDIR(mode))
1824 inode->i_mode |= S_ISGID;
1825 }
1826 dir->i_size += BOGO_DIRENT_SIZE;
1827 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1828 d_instantiate(dentry, inode);
1829 dget(dentry); /* Extra count - pin the dentry in core */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001830 }
1831 return error;
1832}
1833
1834static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1835{
1836 int error;
1837
1838 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
1839 return error;
Dave Hansend8c76e62006-09-30 23:29:04 -07001840 inc_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841 return 0;
1842}
1843
1844static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
1845 struct nameidata *nd)
1846{
1847 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
1848}
1849
1850/*
1851 * Link a file..
1852 */
1853static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1854{
1855 struct inode *inode = old_dentry->d_inode;
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001856 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857
1858 /*
1859 * No ordinary (disk based) filesystem counts links as inodes;
1860 * but each new link needs a new dentry, pinning lowmem, and
1861 * tmpfs dentries cannot be pruned until they are unlinked.
1862 */
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001863 ret = shmem_reserve_inode(inode->i_sb);
1864 if (ret)
1865 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866
1867 dir->i_size += BOGO_DIRENT_SIZE;
1868 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -07001869 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870 atomic_inc(&inode->i_count); /* New dentry reference */
1871 dget(dentry); /* Extra pinning count for the created dentry */
1872 d_instantiate(dentry, inode);
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001873out:
1874 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875}
1876
1877static int shmem_unlink(struct inode *dir, struct dentry *dentry)
1878{
1879 struct inode *inode = dentry->d_inode;
1880
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001881 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
1882 shmem_free_inode(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883
1884 dir->i_size -= BOGO_DIRENT_SIZE;
1885 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001886 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 dput(dentry); /* Undo the count from "create" - this does all the work */
1888 return 0;
1889}
1890
1891static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
1892{
1893 if (!simple_empty(dentry))
1894 return -ENOTEMPTY;
1895
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001896 drop_nlink(dentry->d_inode);
1897 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 return shmem_unlink(dir, dentry);
1899}
1900
1901/*
1902 * The VFS layer already does all the dentry stuff for rename,
1903 * we just have to decrement the usage count for the target if
1904 * it exists so that the VFS layer correctly free's it when it
1905 * gets overwritten.
1906 */
1907static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
1908{
1909 struct inode *inode = old_dentry->d_inode;
1910 int they_are_dirs = S_ISDIR(inode->i_mode);
1911
1912 if (!simple_empty(new_dentry))
1913 return -ENOTEMPTY;
1914
1915 if (new_dentry->d_inode) {
1916 (void) shmem_unlink(new_dir, new_dentry);
1917 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001918 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001920 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -07001921 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922 }
1923
1924 old_dir->i_size -= BOGO_DIRENT_SIZE;
1925 new_dir->i_size += BOGO_DIRENT_SIZE;
1926 old_dir->i_ctime = old_dir->i_mtime =
1927 new_dir->i_ctime = new_dir->i_mtime =
1928 inode->i_ctime = CURRENT_TIME;
1929 return 0;
1930}
1931
1932static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1933{
1934 int error;
1935 int len;
1936 struct inode *inode;
1937 struct page *page = NULL;
1938 char *kaddr;
1939 struct shmem_inode_info *info;
1940
1941 len = strlen(symname) + 1;
1942 if (len > PAGE_CACHE_SIZE)
1943 return -ENAMETOOLONG;
1944
Hugh Dickins0b0a0802009-02-24 20:51:52 +00001945 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946 if (!inode)
1947 return -ENOSPC;
1948
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001949 error = security_inode_init_security(inode, dir, NULL, NULL,
1950 NULL);
1951 if (error) {
1952 if (error != -EOPNOTSUPP) {
1953 iput(inode);
1954 return error;
1955 }
1956 error = 0;
1957 }
1958
Linus Torvalds1da177e2005-04-16 15:20:36 -07001959 info = SHMEM_I(inode);
1960 inode->i_size = len-1;
1961 if (len <= (char *)inode - (char *)info) {
1962 /* do it inline */
1963 memcpy(info, symname, len);
1964 inode->i_op = &shmem_symlink_inline_operations;
1965 } else {
1966 error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
1967 if (error) {
1968 iput(inode);
1969 return error;
1970 }
Hugh Dickinsd3602442008-02-04 22:28:44 -08001971 unlock_page(page);
Hugh Dickins14fcc232008-07-28 15:46:19 -07001972 inode->i_mapping->a_ops = &shmem_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 inode->i_op = &shmem_symlink_inode_operations;
1974 kaddr = kmap_atomic(page, KM_USER0);
1975 memcpy(kaddr, symname, len);
1976 kunmap_atomic(kaddr, KM_USER0);
1977 set_page_dirty(page);
1978 page_cache_release(page);
1979 }
1980 if (dir->i_mode & S_ISGID)
1981 inode->i_gid = dir->i_gid;
1982 dir->i_size += BOGO_DIRENT_SIZE;
1983 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1984 d_instantiate(dentry, inode);
1985 dget(dentry);
1986 return 0;
1987}
1988
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001989static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990{
1991 nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001992 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001993}
1994
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001995static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001996{
1997 struct page *page = NULL;
1998 int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
1999 nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
Hugh Dickinsd3602442008-02-04 22:28:44 -08002000 if (page)
2001 unlock_page(page);
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002002 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003}
2004
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002005static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002006{
2007 if (!IS_ERR(nd_get_link(nd))) {
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002008 struct page *page = cookie;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002009 kunmap(page);
2010 mark_page_accessed(page);
2011 page_cache_release(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002012 }
2013}
2014
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002015static const struct inode_operations shmem_symlink_inline_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002016 .readlink = generic_readlink,
2017 .follow_link = shmem_follow_link_inline,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002018};
2019
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002020static const struct inode_operations shmem_symlink_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021 .truncate = shmem_truncate,
2022 .readlink = generic_readlink,
2023 .follow_link = shmem_follow_link,
2024 .put_link = shmem_put_link,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002025};
2026
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002027#ifdef CONFIG_TMPFS_POSIX_ACL
Randy Dunlap46711812008-03-19 17:00:41 -07002028/*
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002029 * Superblocks without xattr inode operations will get security.* xattr
2030 * support from the VFS "for free". As soon as we have any other xattrs
2031 * like ACLs, we also need to implement the security.* handlers at
2032 * filesystem level, though.
2033 */
2034
2035static size_t shmem_xattr_security_list(struct inode *inode, char *list,
2036 size_t list_len, const char *name,
2037 size_t name_len)
2038{
2039 return security_inode_listsecurity(inode, list, list_len);
2040}
2041
2042static int shmem_xattr_security_get(struct inode *inode, const char *name,
2043 void *buffer, size_t size)
2044{
2045 if (strcmp(name, "") == 0)
2046 return -EINVAL;
David P. Quigley42492592008-02-04 22:29:39 -08002047 return xattr_getsecurity(inode, name, buffer, size);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002048}
2049
2050static int shmem_xattr_security_set(struct inode *inode, const char *name,
2051 const void *value, size_t size, int flags)
2052{
2053 if (strcmp(name, "") == 0)
2054 return -EINVAL;
2055 return security_inode_setsecurity(inode, name, value, size, flags);
2056}
2057
Adrian Bunk1f370a22006-12-06 20:38:21 -08002058static struct xattr_handler shmem_xattr_security_handler = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002059 .prefix = XATTR_SECURITY_PREFIX,
2060 .list = shmem_xattr_security_list,
2061 .get = shmem_xattr_security_get,
2062 .set = shmem_xattr_security_set,
2063};
2064
2065static struct xattr_handler *shmem_xattr_handlers[] = {
2066 &shmem_xattr_acl_access_handler,
2067 &shmem_xattr_acl_default_handler,
2068 &shmem_xattr_security_handler,
2069 NULL
2070};
2071#endif
2072
David M. Grimes91828a42006-10-17 00:09:45 -07002073static struct dentry *shmem_get_parent(struct dentry *child)
2074{
2075 return ERR_PTR(-ESTALE);
2076}
2077
2078static int shmem_match(struct inode *ino, void *vfh)
2079{
2080 __u32 *fh = vfh;
2081 __u64 inum = fh[2];
2082 inum = (inum << 32) | fh[1];
2083 return ino->i_ino == inum && fh[0] == ino->i_generation;
2084}
2085
Christoph Hellwig480b1162007-10-21 16:42:13 -07002086static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
2087 struct fid *fid, int fh_len, int fh_type)
David M. Grimes91828a42006-10-17 00:09:45 -07002088{
David M. Grimes91828a42006-10-17 00:09:45 -07002089 struct inode *inode;
Christoph Hellwig480b1162007-10-21 16:42:13 -07002090 struct dentry *dentry = NULL;
2091 u64 inum = fid->raw[2];
2092 inum = (inum << 32) | fid->raw[1];
David M. Grimes91828a42006-10-17 00:09:45 -07002093
Christoph Hellwig480b1162007-10-21 16:42:13 -07002094 if (fh_len < 3)
2095 return NULL;
2096
2097 inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
2098 shmem_match, fid->raw);
David M. Grimes91828a42006-10-17 00:09:45 -07002099 if (inode) {
Christoph Hellwig480b1162007-10-21 16:42:13 -07002100 dentry = d_find_alias(inode);
David M. Grimes91828a42006-10-17 00:09:45 -07002101 iput(inode);
2102 }
2103
Christoph Hellwig480b1162007-10-21 16:42:13 -07002104 return dentry;
David M. Grimes91828a42006-10-17 00:09:45 -07002105}
2106
2107static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
2108 int connectable)
2109{
2110 struct inode *inode = dentry->d_inode;
2111
2112 if (*len < 3)
2113 return 255;
2114
2115 if (hlist_unhashed(&inode->i_hash)) {
2116 /* Unfortunately insert_inode_hash is not idempotent,
2117 * so as we hash inodes here rather than at creation
2118 * time, we need a lock to ensure we only try
2119 * to do it once
2120 */
2121 static DEFINE_SPINLOCK(lock);
2122 spin_lock(&lock);
2123 if (hlist_unhashed(&inode->i_hash))
2124 __insert_inode_hash(inode,
2125 inode->i_ino + inode->i_generation);
2126 spin_unlock(&lock);
2127 }
2128
2129 fh[0] = inode->i_generation;
2130 fh[1] = inode->i_ino;
2131 fh[2] = ((__u64)inode->i_ino) >> 32;
2132
2133 *len = 3;
2134 return 1;
2135}
2136
Christoph Hellwig39655162007-10-21 16:42:17 -07002137static const struct export_operations shmem_export_ops = {
David M. Grimes91828a42006-10-17 00:09:45 -07002138 .get_parent = shmem_get_parent,
David M. Grimes91828a42006-10-17 00:09:45 -07002139 .encode_fh = shmem_encode_fh,
Christoph Hellwig480b1162007-10-21 16:42:13 -07002140 .fh_to_dentry = shmem_fh_to_dentry,
David M. Grimes91828a42006-10-17 00:09:45 -07002141};
2142
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002143static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
2144 bool remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002145{
2146 char *this_char, *value, *rest;
2147
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002148 while (options != NULL) {
2149 this_char = options;
2150 for (;;) {
2151 /*
2152 * NUL-terminate this option: unfortunately,
2153 * mount options form a comma-separated list,
2154 * but mpol's nodelist may also contain commas.
2155 */
2156 options = strchr(options, ',');
2157 if (options == NULL)
2158 break;
2159 options++;
2160 if (!isdigit(*options)) {
2161 options[-1] = '\0';
2162 break;
2163 }
2164 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165 if (!*this_char)
2166 continue;
2167 if ((value = strchr(this_char,'=')) != NULL) {
2168 *value++ = 0;
2169 } else {
2170 printk(KERN_ERR
2171 "tmpfs: No value for mount option '%s'\n",
2172 this_char);
2173 return 1;
2174 }
2175
2176 if (!strcmp(this_char,"size")) {
2177 unsigned long long size;
2178 size = memparse(value,&rest);
2179 if (*rest == '%') {
2180 size <<= PAGE_SHIFT;
2181 size *= totalram_pages;
2182 do_div(size, 100);
2183 rest++;
2184 }
2185 if (*rest)
2186 goto bad_val;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002187 sbinfo->max_blocks =
2188 DIV_ROUND_UP(size, PAGE_CACHE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002189 } else if (!strcmp(this_char,"nr_blocks")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002190 sbinfo->max_blocks = memparse(value, &rest);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002191 if (*rest)
2192 goto bad_val;
2193 } else if (!strcmp(this_char,"nr_inodes")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002194 sbinfo->max_inodes = memparse(value, &rest);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195 if (*rest)
2196 goto bad_val;
2197 } else if (!strcmp(this_char,"mode")) {
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->mode = simple_strtoul(value, &rest, 8) & 07777;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002201 if (*rest)
2202 goto bad_val;
2203 } else if (!strcmp(this_char,"uid")) {
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->uid = simple_strtoul(value, &rest, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 if (*rest)
2208 goto bad_val;
2209 } else if (!strcmp(this_char,"gid")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002210 if (remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002211 continue;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002212 sbinfo->gid = simple_strtoul(value, &rest, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 if (*rest)
2214 goto bad_val;
Robin Holt7339ff82006-01-14 13:20:48 -08002215 } else if (!strcmp(this_char,"mpol")) {
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07002216 if (mpol_parse_str(value, &sbinfo->mpol, 1))
Robin Holt7339ff82006-01-14 13:20:48 -08002217 goto bad_val;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002218 } else {
2219 printk(KERN_ERR "tmpfs: Bad mount option %s\n",
2220 this_char);
2221 return 1;
2222 }
2223 }
2224 return 0;
2225
2226bad_val:
2227 printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
2228 value, this_char);
2229 return 1;
2230
2231}
2232
2233static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
2234{
2235 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002236 struct shmem_sb_info config = *sbinfo;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002237 unsigned long blocks;
2238 unsigned long inodes;
2239 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002241 if (shmem_parse_options(data, &config, true))
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002242 return error;
2243
2244 spin_lock(&sbinfo->stat_lock);
2245 blocks = sbinfo->max_blocks - sbinfo->free_blocks;
2246 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002247 if (config.max_blocks < blocks)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002248 goto out;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002249 if (config.max_inodes < inodes)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002250 goto out;
2251 /*
2252 * Those tests also disallow limited->unlimited while any are in
2253 * use, so i_blocks will always be zero when max_blocks is zero;
2254 * but we must separately disallow unlimited->limited, because
2255 * in that case we have no record of how much is already in use.
2256 */
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002257 if (config.max_blocks && !sbinfo->max_blocks)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002258 goto out;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002259 if (config.max_inodes && !sbinfo->max_inodes)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002260 goto out;
2261
2262 error = 0;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002263 sbinfo->max_blocks = config.max_blocks;
2264 sbinfo->free_blocks = config.max_blocks - blocks;
2265 sbinfo->max_inodes = config.max_inodes;
2266 sbinfo->free_inodes = config.max_inodes - inodes;
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07002267
2268 mpol_put(sbinfo->mpol);
2269 sbinfo->mpol = config.mpol; /* transfers initial ref */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002270out:
2271 spin_unlock(&sbinfo->stat_lock);
2272 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002274
2275static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs)
2276{
2277 struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb);
2278
2279 if (sbinfo->max_blocks != shmem_default_max_blocks())
2280 seq_printf(seq, ",size=%luk",
2281 sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10));
2282 if (sbinfo->max_inodes != shmem_default_max_inodes())
2283 seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
2284 if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
2285 seq_printf(seq, ",mode=%03o", sbinfo->mode);
2286 if (sbinfo->uid != 0)
2287 seq_printf(seq, ",uid=%u", sbinfo->uid);
2288 if (sbinfo->gid != 0)
2289 seq_printf(seq, ",gid=%u", sbinfo->gid);
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07002290 shmem_show_mpol(seq, sbinfo->mpol);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002291 return 0;
2292}
2293#endif /* CONFIG_TMPFS */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294
2295static void shmem_put_super(struct super_block *sb)
2296{
2297 kfree(sb->s_fs_info);
2298 sb->s_fs_info = NULL;
2299}
2300
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301static int shmem_fill_super(struct super_block *sb,
2302 void *data, int silent)
2303{
2304 struct inode *inode;
2305 struct dentry *root;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002306 struct shmem_sb_info *sbinfo;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002307 int err = -ENOMEM;
2308
2309 /* Round up to L1_CACHE_BYTES to resist false sharing */
2310 sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
2311 L1_CACHE_BYTES), GFP_KERNEL);
2312 if (!sbinfo)
2313 return -ENOMEM;
2314
2315 sbinfo->max_blocks = 0;
2316 sbinfo->max_inodes = 0;
2317 sbinfo->mode = S_IRWXUGO | S_ISVTX;
David Howells76aac0e2008-11-14 10:39:12 +11002318 sbinfo->uid = current_fsuid();
2319 sbinfo->gid = current_fsgid();
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07002320 sbinfo->mpol = NULL;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002321 sb->s_fs_info = sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002323#ifdef CONFIG_TMPFS
Linus Torvalds1da177e2005-04-16 15:20:36 -07002324 /*
2325 * Per default we only allow half of the physical ram per
2326 * tmpfs instance, limiting inodes to one per page of lowmem;
2327 * but the internal instance is left unlimited.
2328 */
2329 if (!(sb->s_flags & MS_NOUSER)) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002330 sbinfo->max_blocks = shmem_default_max_blocks();
2331 sbinfo->max_inodes = shmem_default_max_inodes();
2332 if (shmem_parse_options(data, sbinfo, false)) {
2333 err = -EINVAL;
2334 goto failed;
2335 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336 }
David M. Grimes91828a42006-10-17 00:09:45 -07002337 sb->s_export_op = &shmem_export_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002338#else
2339 sb->s_flags |= MS_NOUSER;
2340#endif
2341
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002342 spin_lock_init(&sbinfo->stat_lock);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002343 sbinfo->free_blocks = sbinfo->max_blocks;
2344 sbinfo->free_inodes = sbinfo->max_inodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002345
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346 sb->s_maxbytes = SHMEM_MAX_BYTES;
2347 sb->s_blocksize = PAGE_CACHE_SIZE;
2348 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2349 sb->s_magic = TMPFS_MAGIC;
2350 sb->s_op = &shmem_ops;
Robin H. Johnsoncfd95a92006-06-12 21:50:25 +01002351 sb->s_time_gran = 1;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002352#ifdef CONFIG_TMPFS_POSIX_ACL
2353 sb->s_xattr = shmem_xattr_handlers;
2354 sb->s_flags |= MS_POSIXACL;
2355#endif
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002356
Hugh Dickins0b0a0802009-02-24 20:51:52 +00002357 inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358 if (!inode)
2359 goto failed;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002360 inode->i_uid = sbinfo->uid;
2361 inode->i_gid = sbinfo->gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002362 root = d_alloc_root(inode);
2363 if (!root)
2364 goto failed_iput;
2365 sb->s_root = root;
2366 return 0;
2367
2368failed_iput:
2369 iput(inode);
2370failed:
2371 shmem_put_super(sb);
2372 return err;
2373}
2374
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002375static struct kmem_cache *shmem_inode_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002376
2377static struct inode *shmem_alloc_inode(struct super_block *sb)
2378{
2379 struct shmem_inode_info *p;
Christoph Lametere94b1762006-12-06 20:33:17 -08002380 p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002381 if (!p)
2382 return NULL;
2383 return &p->vfs_inode;
2384}
2385
2386static void shmem_destroy_inode(struct inode *inode)
2387{
2388 if ((inode->i_mode & S_IFMT) == S_IFREG) {
2389 /* only struct inode is valid if it's an inline symlink */
2390 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
2391 }
2392 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
2393}
2394
Alexey Dobriyan51cc5062008-07-25 19:45:34 -07002395static void init_once(void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002396{
2397 struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
2398
Christoph Lametera35afb82007-05-16 22:10:57 -07002399 inode_init_once(&p->vfs_inode);
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 Dickinsae9764162007-06-04 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,
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07002430 .read = do_sync_read,
Hugh Dickins5402b972008-02-04 22:28:44 -08002431 .write = do_sync_write,
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07002432 .aio_read = shmem_file_aio_read,
Hugh Dickins5402b972008-02-04 22:28:44 -08002433 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002434 .fsync = simple_sync_file,
Hugh Dickinsae9764162007-06-04 10:00:39 +02002435 .splice_read = generic_file_splice_read,
2436 .splice_write = generic_file_splice_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002437#endif
2438};
2439
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002440static const struct inode_operations shmem_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002441 .truncate = shmem_truncate,
2442 .setattr = shmem_notify_change,
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002443 .truncate_range = shmem_truncate_range,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002444#ifdef CONFIG_TMPFS_POSIX_ACL
2445 .setxattr = generic_setxattr,
2446 .getxattr = generic_getxattr,
2447 .listxattr = generic_listxattr,
2448 .removexattr = generic_removexattr,
2449 .permission = shmem_permission,
2450#endif
2451
Linus Torvalds1da177e2005-04-16 15:20:36 -07002452};
2453
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002454static const struct inode_operations shmem_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455#ifdef CONFIG_TMPFS
2456 .create = shmem_create,
2457 .lookup = simple_lookup,
2458 .link = shmem_link,
2459 .unlink = shmem_unlink,
2460 .symlink = shmem_symlink,
2461 .mkdir = shmem_mkdir,
2462 .rmdir = shmem_rmdir,
2463 .mknod = shmem_mknod,
2464 .rename = shmem_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002465#endif
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002466#ifdef CONFIG_TMPFS_POSIX_ACL
2467 .setattr = shmem_notify_change,
2468 .setxattr = generic_setxattr,
2469 .getxattr = generic_getxattr,
2470 .listxattr = generic_listxattr,
2471 .removexattr = generic_removexattr,
2472 .permission = shmem_permission,
2473#endif
2474};
2475
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002476static const struct inode_operations shmem_special_inode_operations = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002477#ifdef CONFIG_TMPFS_POSIX_ACL
2478 .setattr = shmem_notify_change,
2479 .setxattr = generic_setxattr,
2480 .getxattr = generic_getxattr,
2481 .listxattr = generic_listxattr,
2482 .removexattr = generic_removexattr,
2483 .permission = shmem_permission,
2484#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002485};
2486
Hugh Dickins759b9772007-03-05 00:30:28 -08002487static const struct super_operations shmem_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002488 .alloc_inode = shmem_alloc_inode,
2489 .destroy_inode = shmem_destroy_inode,
2490#ifdef CONFIG_TMPFS
2491 .statfs = shmem_statfs,
2492 .remount_fs = shmem_remount_fs,
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002493 .show_options = shmem_show_options,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002494#endif
2495 .delete_inode = shmem_delete_inode,
2496 .drop_inode = generic_delete_inode,
2497 .put_super = shmem_put_super,
2498};
2499
2500static struct vm_operations_struct shmem_vm_ops = {
Nick Piggin54cb8822007-07-19 01:46:59 -07002501 .fault = shmem_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002502#ifdef CONFIG_NUMA
2503 .set_policy = shmem_set_policy,
2504 .get_policy = shmem_get_policy,
2505#endif
2506};
2507
2508
David Howells454e2392006-06-23 02:02:57 -07002509static int shmem_get_sb(struct file_system_type *fs_type,
2510 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002511{
David Howells454e2392006-06-23 02:02:57 -07002512 return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513}
2514
2515static struct file_system_type tmpfs_fs_type = {
2516 .owner = THIS_MODULE,
2517 .name = "tmpfs",
2518 .get_sb = shmem_get_sb,
2519 .kill_sb = kill_litter_super,
2520};
Linus Torvalds1da177e2005-04-16 15:20:36 -07002521
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}
Matt Mackall853ac432009-01-06 14:40:20 -08002559
2560#else /* !CONFIG_SHMEM */
2561
2562/*
2563 * tiny-shmem: simple shmemfs and tmpfs using ramfs code
2564 *
2565 * This is intended for small system where the benefits of the full
2566 * shmem code (swap-backed and resource-limited) are outweighed by
2567 * their complexity. On systems without swap this code should be
2568 * effectively equivalent, but much lighter weight.
2569 */
2570
2571#include <linux/ramfs.h>
2572
2573static struct file_system_type tmpfs_fs_type = {
2574 .name = "tmpfs",
2575 .get_sb = ramfs_get_sb,
2576 .kill_sb = kill_litter_super,
2577};
2578
2579static int __init init_tmpfs(void)
2580{
2581 BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);
2582
2583 shm_mnt = kern_mount(&tmpfs_fs_type);
2584 BUG_ON(IS_ERR(shm_mnt));
2585
2586 return 0;
2587}
2588
2589int shmem_unuse(swp_entry_t entry, struct page *page)
2590{
2591 return 0;
2592}
2593
Hugh Dickins0b0a0802009-02-24 20:51:52 +00002594#define shmem_vm_ops generic_file_vm_ops
2595#define shmem_file_operations ramfs_file_operations
2596#define shmem_get_inode(sb, mode, dev, flags) ramfs_get_inode(sb, mode, dev)
2597#define shmem_acct_size(flags, size) 0
2598#define shmem_unacct_size(flags, size) do {} while (0)
Hugh Dickinscaefba12009-04-13 14:40:12 -07002599#define SHMEM_MAX_BYTES MAX_LFS_FILESIZE
Matt Mackall853ac432009-01-06 14:40:20 -08002600
2601#endif /* CONFIG_SHMEM */
2602
2603/* common code */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002604
Randy Dunlap46711812008-03-19 17:00:41 -07002605/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002606 * shmem_file_setup - get an unlinked file living in tmpfs
Linus Torvalds1da177e2005-04-16 15:20:36 -07002607 * @name: name for dentry (to be seen in /proc/<pid>/maps
2608 * @size: size to be set for the file
Hugh Dickins0b0a0802009-02-24 20:51:52 +00002609 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
Linus Torvalds1da177e2005-04-16 15:20:36 -07002610 */
Sergei Trofimovich168f5ac2009-06-16 15:33:02 -07002611struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002612{
2613 int error;
2614 struct file *file;
2615 struct inode *inode;
2616 struct dentry *dentry, *root;
2617 struct qstr this;
2618
2619 if (IS_ERR(shm_mnt))
2620 return (void *)shm_mnt;
2621
2622 if (size < 0 || size > SHMEM_MAX_BYTES)
2623 return ERR_PTR(-EINVAL);
2624
2625 if (shmem_acct_size(flags, size))
2626 return ERR_PTR(-ENOMEM);
2627
2628 error = -ENOMEM;
2629 this.name = name;
2630 this.len = strlen(name);
2631 this.hash = 0; /* will go */
2632 root = shm_mnt->mnt_root;
2633 dentry = d_alloc(root, &this);
2634 if (!dentry)
2635 goto put_memory;
2636
2637 error = -ENFILE;
2638 file = get_empty_filp();
2639 if (!file)
2640 goto put_dentry;
2641
2642 error = -ENOSPC;
Hugh Dickins0b0a0802009-02-24 20:51:52 +00002643 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002644 if (!inode)
2645 goto close_file;
2646
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647 d_instantiate(dentry, inode);
2648 inode->i_size = size;
2649 inode->i_nlink = 0; /* It is unlinked */
Dave Hansence8d2cd2007-10-16 23:31:13 -07002650 init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
Matt Mackall853ac432009-01-06 14:40:20 -08002651 &shmem_file_operations);
2652
2653#ifndef CONFIG_MMU
2654 error = ramfs_nommu_expand_for_mapping(inode, size);
2655 if (error)
2656 goto close_file;
2657#endif
Mimi Zoharc9d9ac52009-05-19 13:25:58 -04002658 ima_counts_get(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002659 return file;
2660
2661close_file:
2662 put_filp(file);
2663put_dentry:
2664 dput(dentry);
2665put_memory:
2666 shmem_unacct_size(flags, size);
2667 return ERR_PTR(error);
2668}
Keith Packard395e0dd2008-06-20 00:08:06 -07002669EXPORT_SYMBOL_GPL(shmem_file_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002670
Randy Dunlap46711812008-03-19 17:00:41 -07002671/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002672 * shmem_zero_setup - setup a shared anonymous mapping
Linus Torvalds1da177e2005-04-16 15:20:36 -07002673 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2674 */
2675int shmem_zero_setup(struct vm_area_struct *vma)
2676{
2677 struct file *file;
2678 loff_t size = vma->vm_end - vma->vm_start;
2679
2680 file = shmem_file_setup("dev/zero", size, vma->vm_flags);
2681 if (IS_ERR(file))
2682 return PTR_ERR(file);
2683
2684 if (vma->vm_file)
2685 fput(vma->vm_file);
2686 vma->vm_file = file;
2687 vma->vm_ops = &shmem_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002688 return 0;
2689}
Matt Mackall853ac432009-01-06 14:40:20 -08002690
2691module_init(init_tmpfs)