blob: 51b3d6ccddab75ba33b7fded5ffaf75700770ccd [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Resizable virtual memory filesystem for Linux.
3 *
4 * Copyright (C) 2000 Linus Torvalds.
5 * 2000 Transmeta Corp.
6 * 2000-2001 Christoph Rohland
7 * 2000-2001 SAP AG
8 * 2002 Red Hat Inc.
Hugh Dickins0edd73b2005-06-21 17:15:04 -07009 * Copyright (C) 2002-2005 Hugh Dickins.
10 * Copyright (C) 2002-2005 VERITAS Software Corporation.
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * Copyright (C) 2004 Andi Kleen, SuSE Labs
12 *
13 * Extended attribute support for tmpfs:
14 * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
15 * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
16 *
17 * This file is released under the GPL.
18 */
19
20/*
21 * This virtual memory filesystem is heavily based on the ramfs. It
22 * extends ramfs by the ability to use swap and honor resource limits
23 * which makes it a completely usable filesystem.
24 */
25
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/module.h>
27#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/fs.h>
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070029#include <linux/xattr.h>
Christoph Hellwiga5694252007-07-17 04:04:28 -070030#include <linux/exportfs.h>
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070031#include <linux/generic_acl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/mm.h>
33#include <linux/mman.h>
34#include <linux/file.h>
35#include <linux/swap.h>
36#include <linux/pagemap.h>
37#include <linux/string.h>
38#include <linux/slab.h>
39#include <linux/backing-dev.h>
40#include <linux/shmem_fs.h>
41#include <linux/mount.h>
42#include <linux/writeback.h>
43#include <linux/vfs.h>
44#include <linux/blkdev.h>
45#include <linux/security.h>
46#include <linux/swapops.h>
47#include <linux/mempolicy.h>
48#include <linux/namei.h>
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +000049#include <linux/ctype.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070050#include <linux/migrate.h>
Christoph Lameterc1f60a52006-09-25 23:31:11 -070051#include <linux/highmem.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070052
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#include <asm/uaccess.h>
54#include <asm/div64.h>
55#include <asm/pgtable.h>
56
57/* This magic number is used in glibc for posix shared memory */
58#define TMPFS_MAGIC 0x01021994
59
60#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
61#define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
62#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
63
64#define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
65#define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT)
66
67#define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
68
69/* info->flags needs VM_flags to handle pagein/truncate races efficiently */
70#define SHMEM_PAGEIN VM_READ
71#define SHMEM_TRUNCATE VM_WRITE
72
73/* Definition to limit shmem_truncate's steps between cond_rescheds */
74#define LATENCY_LIMIT 64
75
76/* Pretend that each entry is of this size in directory's i_size */
77#define BOGO_DIRENT_SIZE 20
78
Linus Torvalds1da177e2005-04-16 15:20:36 -070079/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
80enum sgp_type {
81 SGP_QUICK, /* don't try more than file page cache lookup */
82 SGP_READ, /* don't exceed i_size, don't allocate page */
83 SGP_CACHE, /* don't exceed i_size, may allocate page */
84 SGP_WRITE, /* may exceed i_size, may allocate page */
Nick Piggin54cb8822007-07-19 01:46:59 -070085 SGP_FAULT, /* same as SGP_CACHE, return with page locked */
Linus Torvalds1da177e2005-04-16 15:20:36 -070086};
87
88static int shmem_getpage(struct inode *inode, unsigned long idx,
89 struct page **pagep, enum sgp_type sgp, int *type);
90
Al Viro6daa0e22005-10-21 03:18:50 -040091static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -070092{
93 /*
94 * The above definition of ENTRIES_PER_PAGE, and the use of
95 * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
96 * might be reconsidered if it ever diverges from PAGE_SIZE.
Mel Gorman769848c2007-07-17 04:03:05 -070097 *
Mel Gormane12ba742007-10-16 01:25:52 -070098 * Mobility flags are masked out as swap vectors cannot move
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 */
Mel Gormane12ba742007-10-16 01:25:52 -0700100 return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO,
Mel Gorman769848c2007-07-17 04:03:05 -0700101 PAGE_CACHE_SHIFT-PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102}
103
104static inline void shmem_dir_free(struct page *page)
105{
106 __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT);
107}
108
109static struct page **shmem_dir_map(struct page *page)
110{
111 return (struct page **)kmap_atomic(page, KM_USER0);
112}
113
114static inline void shmem_dir_unmap(struct page **dir)
115{
116 kunmap_atomic(dir, KM_USER0);
117}
118
119static swp_entry_t *shmem_swp_map(struct page *page)
120{
121 return (swp_entry_t *)kmap_atomic(page, KM_USER1);
122}
123
124static inline void shmem_swp_balance_unmap(void)
125{
126 /*
127 * When passing a pointer to an i_direct entry, to code which
128 * also handles indirect entries and so will shmem_swp_unmap,
129 * we must arrange for the preempt count to remain in balance.
130 * What kmap_atomic of a lowmem page does depends on config
131 * and architecture, so pretend to kmap_atomic some lowmem page.
132 */
133 (void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
134}
135
136static inline void shmem_swp_unmap(swp_entry_t *entry)
137{
138 kunmap_atomic(entry, KM_USER1);
139}
140
141static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
142{
143 return sb->s_fs_info;
144}
145
146/*
147 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
148 * for shared memory and for shared anonymous (/dev/zero) mappings
149 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
150 * consistent with the pre-accounting of private mappings ...
151 */
152static inline int shmem_acct_size(unsigned long flags, loff_t size)
153{
154 return (flags & VM_ACCOUNT)?
155 security_vm_enough_memory(VM_ACCT(size)): 0;
156}
157
158static inline void shmem_unacct_size(unsigned long flags, loff_t size)
159{
160 if (flags & VM_ACCOUNT)
161 vm_unacct_memory(VM_ACCT(size));
162}
163
164/*
165 * ... whereas tmpfs objects are accounted incrementally as
166 * pages are allocated, in order to allow huge sparse files.
167 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
168 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
169 */
170static inline int shmem_acct_block(unsigned long flags)
171{
172 return (flags & VM_ACCOUNT)?
173 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE));
174}
175
176static inline void shmem_unacct_blocks(unsigned long flags, long pages)
177{
178 if (!(flags & VM_ACCOUNT))
179 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
180}
181
Hugh Dickins759b9772007-03-05 00:30:28 -0800182static const struct super_operations shmem_ops;
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700183static const struct address_space_operations shmem_aops;
Helge Deller15ad7cd2006-12-06 20:40:36 -0800184static const struct file_operations shmem_file_operations;
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800185static const struct inode_operations shmem_inode_operations;
186static const struct inode_operations shmem_dir_inode_operations;
187static const struct inode_operations shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188static struct vm_operations_struct shmem_vm_ops;
189
Ravikiran G Thirumalai6c231b72005-09-06 15:17:45 -0700190static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 .ra_pages = 0, /* No readahead */
192 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
193 .unplug_io_fn = default_unplug_io_fn,
194};
195
196static LIST_HEAD(shmem_swaplist);
197static DEFINE_SPINLOCK(shmem_swaplist_lock);
198
199static void shmem_free_blocks(struct inode *inode, long pages)
200{
201 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700202 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 spin_lock(&sbinfo->stat_lock);
204 sbinfo->free_blocks += pages;
205 inode->i_blocks -= pages*BLOCKS_PER_PAGE;
206 spin_unlock(&sbinfo->stat_lock);
207 }
208}
209
210/*
211 * shmem_recalc_inode - recalculate the size of an inode
212 *
213 * @inode: inode to recalc
214 *
215 * We have to calculate the free blocks since the mm can drop
216 * undirtied hole pages behind our back.
217 *
218 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
219 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
220 *
221 * It has to be called with the spinlock held.
222 */
223static void shmem_recalc_inode(struct inode *inode)
224{
225 struct shmem_inode_info *info = SHMEM_I(inode);
226 long freed;
227
228 freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
229 if (freed > 0) {
230 info->alloced -= freed;
231 shmem_unacct_blocks(info->flags, freed);
232 shmem_free_blocks(inode, freed);
233 }
234}
235
236/*
237 * shmem_swp_entry - find the swap vector position in the info structure
238 *
239 * @info: info structure for the inode
240 * @index: index of the page to find
241 * @page: optional page to add to the structure. Has to be preset to
242 * all zeros
243 *
244 * If there is no space allocated yet it will return NULL when
245 * page is NULL, else it will use the page for the needed block,
246 * setting it to NULL on return to indicate that it has been used.
247 *
248 * The swap vector is organized the following way:
249 *
250 * There are SHMEM_NR_DIRECT entries directly stored in the
251 * shmem_inode_info structure. So small files do not need an addional
252 * allocation.
253 *
254 * For pages with index > SHMEM_NR_DIRECT there is the pointer
255 * i_indirect which points to a page which holds in the first half
256 * doubly indirect blocks, in the second half triple indirect blocks:
257 *
258 * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the
259 * following layout (for SHMEM_NR_DIRECT == 16):
260 *
261 * i_indirect -> dir --> 16-19
262 * | +-> 20-23
263 * |
264 * +-->dir2 --> 24-27
265 * | +-> 28-31
266 * | +-> 32-35
267 * | +-> 36-39
268 * |
269 * +-->dir3 --> 40-43
270 * +-> 44-47
271 * +-> 48-51
272 * +-> 52-55
273 */
274static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page)
275{
276 unsigned long offset;
277 struct page **dir;
278 struct page *subdir;
279
280 if (index < SHMEM_NR_DIRECT) {
281 shmem_swp_balance_unmap();
282 return info->i_direct+index;
283 }
284 if (!info->i_indirect) {
285 if (page) {
286 info->i_indirect = *page;
287 *page = NULL;
288 }
289 return NULL; /* need another page */
290 }
291
292 index -= SHMEM_NR_DIRECT;
293 offset = index % ENTRIES_PER_PAGE;
294 index /= ENTRIES_PER_PAGE;
295 dir = shmem_dir_map(info->i_indirect);
296
297 if (index >= ENTRIES_PER_PAGE/2) {
298 index -= ENTRIES_PER_PAGE/2;
299 dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE;
300 index %= ENTRIES_PER_PAGE;
301 subdir = *dir;
302 if (!subdir) {
303 if (page) {
304 *dir = *page;
305 *page = NULL;
306 }
307 shmem_dir_unmap(dir);
308 return NULL; /* need another page */
309 }
310 shmem_dir_unmap(dir);
311 dir = shmem_dir_map(subdir);
312 }
313
314 dir += index;
315 subdir = *dir;
316 if (!subdir) {
317 if (!page || !(subdir = *page)) {
318 shmem_dir_unmap(dir);
319 return NULL; /* need a page */
320 }
321 *dir = subdir;
322 *page = NULL;
323 }
324 shmem_dir_unmap(dir);
325 return shmem_swp_map(subdir) + offset;
326}
327
328static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
329{
330 long incdec = value? 1: -1;
331
332 entry->val = value;
333 info->swapped += incdec;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700334 if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
335 struct page *page = kmap_atomic_to_page(entry);
336 set_page_private(page, page_private(page) + incdec);
337 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338}
339
340/*
341 * shmem_swp_alloc - get the position of the swap entry for the page.
342 * If it does not exist allocate the entry.
343 *
344 * @info: info structure for the inode
345 * @index: index of the page to find
346 * @sgp: check and recheck i_size? skip allocation?
347 */
348static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp)
349{
350 struct inode *inode = &info->vfs_inode;
351 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
352 struct page *page = NULL;
353 swp_entry_t *entry;
354
355 if (sgp != SGP_WRITE &&
356 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
357 return ERR_PTR(-EINVAL);
358
359 while (!(entry = shmem_swp_entry(info, index, &page))) {
360 if (sgp == SGP_READ)
361 return shmem_swp_map(ZERO_PAGE(0));
362 /*
363 * Test free_blocks against 1 not 0, since we have 1 data
364 * page (and perhaps indirect index pages) yet to allocate:
365 * a waste to allocate index if we cannot allocate data.
366 */
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700367 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 spin_lock(&sbinfo->stat_lock);
369 if (sbinfo->free_blocks <= 1) {
370 spin_unlock(&sbinfo->stat_lock);
371 return ERR_PTR(-ENOSPC);
372 }
373 sbinfo->free_blocks--;
374 inode->i_blocks += BLOCKS_PER_PAGE;
375 spin_unlock(&sbinfo->stat_lock);
376 }
377
378 spin_unlock(&info->lock);
Mel Gorman769848c2007-07-17 04:03:05 -0700379 page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping));
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700380 if (page)
381 set_page_private(page, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 spin_lock(&info->lock);
383
384 if (!page) {
385 shmem_free_blocks(inode, 1);
386 return ERR_PTR(-ENOMEM);
387 }
388 if (sgp != SGP_WRITE &&
389 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
390 entry = ERR_PTR(-EINVAL);
391 break;
392 }
393 if (info->next_index <= index)
394 info->next_index = index + 1;
395 }
396 if (page) {
397 /* another task gave its page, or truncated the file */
398 shmem_free_blocks(inode, 1);
399 shmem_dir_free(page);
400 }
401 if (info->next_index <= index && !IS_ERR(entry))
402 info->next_index = index + 1;
403 return entry;
404}
405
406/*
407 * shmem_free_swp - free some swap entries in a directory
408 *
Hugh Dickins1ae70002007-03-29 01:20:36 -0700409 * @dir: pointer to the directory
410 * @edir: pointer after last entry of the directory
411 * @punch_lock: pointer to spinlock when needed for the holepunch case
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 */
Hugh Dickins1ae70002007-03-29 01:20:36 -0700413static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
414 spinlock_t *punch_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415{
Hugh Dickins1ae70002007-03-29 01:20:36 -0700416 spinlock_t *punch_unlock = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 swp_entry_t *ptr;
418 int freed = 0;
419
420 for (ptr = dir; ptr < edir; ptr++) {
421 if (ptr->val) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700422 if (unlikely(punch_lock)) {
423 punch_unlock = punch_lock;
424 punch_lock = NULL;
425 spin_lock(punch_unlock);
426 if (!ptr->val)
427 continue;
428 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 free_swap_and_cache(*ptr);
430 *ptr = (swp_entry_t){0};
431 freed++;
432 }
433 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700434 if (punch_unlock)
435 spin_unlock(punch_unlock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 return freed;
437}
438
Hugh Dickins1ae70002007-03-29 01:20:36 -0700439static int shmem_map_and_free_swp(struct page *subdir, int offset,
440 int limit, struct page ***dir, spinlock_t *punch_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441{
442 swp_entry_t *ptr;
443 int freed = 0;
444
445 ptr = shmem_swp_map(subdir);
446 for (; offset < limit; offset += LATENCY_LIMIT) {
447 int size = limit - offset;
448 if (size > LATENCY_LIMIT)
449 size = LATENCY_LIMIT;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700450 freed += shmem_free_swp(ptr+offset, ptr+offset+size,
451 punch_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 if (need_resched()) {
453 shmem_swp_unmap(ptr);
454 if (*dir) {
455 shmem_dir_unmap(*dir);
456 *dir = NULL;
457 }
458 cond_resched();
459 ptr = shmem_swp_map(subdir);
460 }
461 }
462 shmem_swp_unmap(ptr);
463 return freed;
464}
465
466static void shmem_free_pages(struct list_head *next)
467{
468 struct page *page;
469 int freed = 0;
470
471 do {
472 page = container_of(next, struct page, lru);
473 next = next->next;
474 shmem_dir_free(page);
475 freed++;
476 if (freed >= LATENCY_LIMIT) {
477 cond_resched();
478 freed = 0;
479 }
480 } while (next);
481}
482
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800483static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484{
485 struct shmem_inode_info *info = SHMEM_I(inode);
486 unsigned long idx;
487 unsigned long size;
488 unsigned long limit;
489 unsigned long stage;
490 unsigned long diroff;
491 struct page **dir;
492 struct page *topdir;
493 struct page *middir;
494 struct page *subdir;
495 swp_entry_t *ptr;
496 LIST_HEAD(pages_to_free);
497 long nr_pages_to_free = 0;
498 long nr_swaps_freed = 0;
499 int offset;
500 int freed;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700501 int punch_hole;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700502 spinlock_t *needs_lock;
503 spinlock_t *punch_lock;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700504 unsigned long upper_limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505
506 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800507 idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 if (idx >= info->next_index)
509 return;
510
511 spin_lock(&info->lock);
512 info->flags |= SHMEM_TRUNCATE;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800513 if (likely(end == (loff_t) -1)) {
514 limit = info->next_index;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700515 upper_limit = SHMEM_MAX_INDEX;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800516 info->next_index = idx;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700517 needs_lock = NULL;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700518 punch_hole = 0;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800519 } else {
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700520 if (end + 1 >= inode->i_size) { /* we may free a little more */
521 limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >>
522 PAGE_CACHE_SHIFT;
523 upper_limit = SHMEM_MAX_INDEX;
524 } else {
525 limit = (end + 1) >> PAGE_CACHE_SHIFT;
526 upper_limit = limit;
527 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700528 needs_lock = &info->lock;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800529 punch_hole = 1;
530 }
531
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 topdir = info->i_indirect;
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800533 if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 info->i_indirect = NULL;
535 nr_pages_to_free++;
536 list_add(&topdir->lru, &pages_to_free);
537 }
538 spin_unlock(&info->lock);
539
540 if (info->swapped && idx < SHMEM_NR_DIRECT) {
541 ptr = info->i_direct;
542 size = limit;
543 if (size > SHMEM_NR_DIRECT)
544 size = SHMEM_NR_DIRECT;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700545 nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 }
Badari Pulavarty92a3d032006-12-22 01:06:23 -0800547
548 /*
549 * If there are no indirect blocks or we are punching a hole
550 * below indirect blocks, nothing to be done.
551 */
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700552 if (!topdir || limit <= SHMEM_NR_DIRECT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 goto done2;
554
Hugh Dickins1ae70002007-03-29 01:20:36 -0700555 /*
556 * The truncation case has already dropped info->lock, and we're safe
557 * because i_size and next_index have already been lowered, preventing
558 * access beyond. But in the punch_hole case, we still need to take
559 * the lock when updating the swap directory, because there might be
560 * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or
561 * shmem_writepage. However, whenever we find we can remove a whole
562 * directory page (not at the misaligned start or end of the range),
563 * we first NULLify its pointer in the level above, and then have no
564 * need to take the lock when updating its contents: needs_lock and
565 * punch_lock (either pointing to info->lock or NULL) manage this.
566 */
567
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700568 upper_limit -= SHMEM_NR_DIRECT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 limit -= SHMEM_NR_DIRECT;
570 idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
571 offset = idx % ENTRIES_PER_PAGE;
572 idx -= offset;
573
574 dir = shmem_dir_map(topdir);
575 stage = ENTRIES_PER_PAGEPAGE/2;
576 if (idx < ENTRIES_PER_PAGEPAGE/2) {
577 middir = topdir;
578 diroff = idx/ENTRIES_PER_PAGE;
579 } else {
580 dir += ENTRIES_PER_PAGE/2;
581 dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
582 while (stage <= idx)
583 stage += ENTRIES_PER_PAGEPAGE;
584 middir = *dir;
585 if (*dir) {
586 diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
587 ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700588 if (!diroff && !offset && upper_limit >= stage) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700589 if (needs_lock) {
590 spin_lock(needs_lock);
591 *dir = NULL;
592 spin_unlock(needs_lock);
593 needs_lock = NULL;
594 } else
595 *dir = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 nr_pages_to_free++;
597 list_add(&middir->lru, &pages_to_free);
598 }
599 shmem_dir_unmap(dir);
600 dir = shmem_dir_map(middir);
601 } else {
602 diroff = 0;
603 offset = 0;
604 idx = stage;
605 }
606 }
607
608 for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
609 if (unlikely(idx == stage)) {
610 shmem_dir_unmap(dir);
611 dir = shmem_dir_map(topdir) +
612 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
613 while (!*dir) {
614 dir++;
615 idx += ENTRIES_PER_PAGEPAGE;
616 if (idx >= limit)
617 goto done1;
618 }
619 stage = idx + ENTRIES_PER_PAGEPAGE;
620 middir = *dir;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700621 if (punch_hole)
622 needs_lock = &info->lock;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700623 if (upper_limit >= stage) {
Hugh Dickins1ae70002007-03-29 01:20:36 -0700624 if (needs_lock) {
625 spin_lock(needs_lock);
626 *dir = NULL;
627 spin_unlock(needs_lock);
628 needs_lock = NULL;
629 } else
630 *dir = NULL;
Hugh Dickinsa2646d12007-03-29 01:20:35 -0700631 nr_pages_to_free++;
632 list_add(&middir->lru, &pages_to_free);
633 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 shmem_dir_unmap(dir);
635 cond_resched();
636 dir = shmem_dir_map(middir);
637 diroff = 0;
638 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700639 punch_lock = needs_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 subdir = dir[diroff];
Hugh Dickins1ae70002007-03-29 01:20:36 -0700641 if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) {
642 if (needs_lock) {
643 spin_lock(needs_lock);
644 dir[diroff] = NULL;
645 spin_unlock(needs_lock);
646 punch_lock = NULL;
647 } else
648 dir[diroff] = NULL;
649 nr_pages_to_free++;
650 list_add(&subdir->lru, &pages_to_free);
651 }
652 if (subdir && page_private(subdir) /* has swap entries */) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 size = limit - idx;
654 if (size > ENTRIES_PER_PAGE)
655 size = ENTRIES_PER_PAGE;
656 freed = shmem_map_and_free_swp(subdir,
Hugh Dickins1ae70002007-03-29 01:20:36 -0700657 offset, size, &dir, punch_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 if (!dir)
659 dir = shmem_dir_map(middir);
660 nr_swaps_freed += freed;
Hugh Dickins1ae70002007-03-29 01:20:36 -0700661 if (offset || punch_lock) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 spin_lock(&info->lock);
Hugh Dickins1ae70002007-03-29 01:20:36 -0700663 set_page_private(subdir,
664 page_private(subdir) - freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 spin_unlock(&info->lock);
Hugh Dickins1ae70002007-03-29 01:20:36 -0700666 } else
667 BUG_ON(page_private(subdir) != freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 }
Hugh Dickins1ae70002007-03-29 01:20:36 -0700669 offset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 }
671done1:
672 shmem_dir_unmap(dir);
673done2:
674 if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
675 /*
676 * Call truncate_inode_pages again: racing shmem_unuse_inode
677 * may have swizzled a page in from swap since vmtruncate or
678 * generic_delete_inode did it, before we lowered next_index.
679 * Also, though shmem_getpage checks i_size before adding to
680 * cache, no recheck after: so fix the narrow window there too.
Hugh Dickins16a10012007-03-29 01:20:37 -0700681 *
682 * Recalling truncate_inode_pages_range and unmap_mapping_range
683 * every time for punch_hole (which never got a chance to clear
684 * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive,
685 * yet hardly ever necessary: try to optimize them out later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 */
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800687 truncate_inode_pages_range(inode->i_mapping, start, end);
Hugh Dickins16a10012007-03-29 01:20:37 -0700688 if (punch_hole)
689 unmap_mapping_range(inode->i_mapping, start,
690 end - start, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 }
692
693 spin_lock(&info->lock);
694 info->flags &= ~SHMEM_TRUNCATE;
695 info->swapped -= nr_swaps_freed;
696 if (nr_pages_to_free)
697 shmem_free_blocks(inode, nr_pages_to_free);
698 shmem_recalc_inode(inode);
699 spin_unlock(&info->lock);
700
701 /*
702 * Empty swap vector directory pages to be freed?
703 */
704 if (!list_empty(&pages_to_free)) {
705 pages_to_free.prev->next = NULL;
706 shmem_free_pages(pages_to_free.next);
707 }
708}
709
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -0800710static void shmem_truncate(struct inode *inode)
711{
712 shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
713}
714
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
716{
717 struct inode *inode = dentry->d_inode;
718 struct page *page = NULL;
719 int error;
720
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700721 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 if (attr->ia_size < inode->i_size) {
723 /*
724 * If truncating down to a partial page, then
725 * if that page is already allocated, hold it
726 * in memory until the truncation is over, so
727 * truncate_partial_page cannnot miss it were
728 * it assigned to swap.
729 */
730 if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
731 (void) shmem_getpage(inode,
732 attr->ia_size>>PAGE_CACHE_SHIFT,
733 &page, SGP_READ, NULL);
734 }
735 /*
736 * Reset SHMEM_PAGEIN flag so that shmem_truncate can
737 * detect if any pages might have been added to cache
738 * after truncate_inode_pages. But we needn't bother
739 * if it's being fully truncated to zero-length: the
740 * nrpages check is efficient enough in that case.
741 */
742 if (attr->ia_size) {
743 struct shmem_inode_info *info = SHMEM_I(inode);
744 spin_lock(&info->lock);
745 info->flags &= ~SHMEM_PAGEIN;
746 spin_unlock(&info->lock);
747 }
748 }
749 }
750
751 error = inode_change_ok(inode, attr);
752 if (!error)
753 error = inode_setattr(inode, attr);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700754#ifdef CONFIG_TMPFS_POSIX_ACL
755 if (!error && (attr->ia_valid & ATTR_MODE))
756 error = generic_acl_chmod(inode, &shmem_acl_ops);
757#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 if (page)
759 page_cache_release(page);
760 return error;
761}
762
763static void shmem_delete_inode(struct inode *inode)
764{
765 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
766 struct shmem_inode_info *info = SHMEM_I(inode);
767
768 if (inode->i_op->truncate == shmem_truncate) {
Mark Fashehfef26652005-09-09 13:01:31 -0700769 truncate_inode_pages(inode->i_mapping, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 shmem_unacct_size(info->flags, inode->i_size);
771 inode->i_size = 0;
772 shmem_truncate(inode);
773 if (!list_empty(&info->swaplist)) {
774 spin_lock(&shmem_swaplist_lock);
775 list_del_init(&info->swaplist);
776 spin_unlock(&shmem_swaplist_lock);
777 }
778 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -0700779 BUG_ON(inode->i_blocks);
780 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 spin_lock(&sbinfo->stat_lock);
782 sbinfo->free_inodes++;
783 spin_unlock(&sbinfo->stat_lock);
784 }
785 clear_inode(inode);
786}
787
788static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
789{
790 swp_entry_t *ptr;
791
792 for (ptr = dir; ptr < edir; ptr++) {
793 if (ptr->val == entry.val)
794 return ptr - dir;
795 }
796 return -1;
797}
798
799static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
800{
801 struct inode *inode;
802 unsigned long idx;
803 unsigned long size;
804 unsigned long limit;
805 unsigned long stage;
806 struct page **dir;
807 struct page *subdir;
808 swp_entry_t *ptr;
809 int offset;
810
811 idx = 0;
812 ptr = info->i_direct;
813 spin_lock(&info->lock);
814 limit = info->next_index;
815 size = limit;
816 if (size > SHMEM_NR_DIRECT)
817 size = SHMEM_NR_DIRECT;
818 offset = shmem_find_swp(entry, ptr, ptr+size);
819 if (offset >= 0) {
820 shmem_swp_balance_unmap();
821 goto found;
822 }
823 if (!info->i_indirect)
824 goto lost2;
825
826 dir = shmem_dir_map(info->i_indirect);
827 stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
828
829 for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
830 if (unlikely(idx == stage)) {
831 shmem_dir_unmap(dir-1);
832 dir = shmem_dir_map(info->i_indirect) +
833 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
834 while (!*dir) {
835 dir++;
836 idx += ENTRIES_PER_PAGEPAGE;
837 if (idx >= limit)
838 goto lost1;
839 }
840 stage = idx + ENTRIES_PER_PAGEPAGE;
841 subdir = *dir;
842 shmem_dir_unmap(dir);
843 dir = shmem_dir_map(subdir);
844 }
845 subdir = *dir;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700846 if (subdir && page_private(subdir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 ptr = shmem_swp_map(subdir);
848 size = limit - idx;
849 if (size > ENTRIES_PER_PAGE)
850 size = ENTRIES_PER_PAGE;
851 offset = shmem_find_swp(entry, ptr, ptr+size);
852 if (offset >= 0) {
853 shmem_dir_unmap(dir);
854 goto found;
855 }
856 shmem_swp_unmap(ptr);
857 }
858 }
859lost1:
860 shmem_dir_unmap(dir-1);
861lost2:
862 spin_unlock(&info->lock);
863 return 0;
864found:
865 idx += offset;
866 inode = &info->vfs_inode;
867 if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) {
868 info->flags |= SHMEM_PAGEIN;
869 shmem_swp_set(info, ptr + offset, 0);
870 }
871 shmem_swp_unmap(ptr);
872 spin_unlock(&info->lock);
873 /*
874 * Decrement swap count even when the entry is left behind:
875 * try_to_unuse will skip over mms, then reincrement count.
876 */
877 swap_free(entry);
878 return 1;
879}
880
881/*
882 * shmem_unuse() search for an eventually swapped out shmem page.
883 */
884int shmem_unuse(swp_entry_t entry, struct page *page)
885{
886 struct list_head *p, *next;
887 struct shmem_inode_info *info;
888 int found = 0;
889
890 spin_lock(&shmem_swaplist_lock);
891 list_for_each_safe(p, next, &shmem_swaplist) {
892 info = list_entry(p, struct shmem_inode_info, swaplist);
893 if (!info->swapped)
894 list_del_init(&info->swaplist);
895 else if (shmem_unuse_inode(info, entry, page)) {
896 /* move head to start search for next from here */
897 list_move_tail(&shmem_swaplist, &info->swaplist);
898 found = 1;
899 break;
900 }
901 }
902 spin_unlock(&shmem_swaplist_lock);
903 return found;
904}
905
906/*
907 * Move the page from the page cache to the swap cache.
908 */
909static int shmem_writepage(struct page *page, struct writeback_control *wbc)
910{
911 struct shmem_inode_info *info;
912 swp_entry_t *entry, swap;
913 struct address_space *mapping;
914 unsigned long index;
915 struct inode *inode;
916
917 BUG_ON(!PageLocked(page));
Hugh Dickins487e9bf2007-10-29 14:37:20 -0700918 /*
919 * shmem_backing_dev_info's capabilities prevent regular writeback or
920 * sync from ever calling shmem_writepage; but a stacking filesystem
921 * may use the ->writepage of its underlying filesystem, in which case
922 * we want to do nothing when that underlying filesystem is tmpfs
923 * (writing out to swap is useful as a response to memory pressure, but
924 * of no use to stabilize the data) - just redirty the page, unlock it
925 * and claim success in this case. AOP_WRITEPAGE_ACTIVATE, and the
926 * page_mapped check below, must be avoided unless we're in reclaim.
927 */
928 if (!wbc->for_reclaim) {
929 set_page_dirty(page);
930 unlock_page(page);
931 return 0;
932 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 BUG_ON(page_mapped(page));
934
935 mapping = page->mapping;
936 index = page->index;
937 inode = mapping->host;
938 info = SHMEM_I(inode);
939 if (info->flags & VM_LOCKED)
940 goto redirty;
941 swap = get_swap_page();
942 if (!swap.val)
943 goto redirty;
944
945 spin_lock(&info->lock);
946 shmem_recalc_inode(inode);
947 if (index >= info->next_index) {
948 BUG_ON(!(info->flags & SHMEM_TRUNCATE));
949 goto unlock;
950 }
951 entry = shmem_swp_entry(info, index, NULL);
952 BUG_ON(!entry);
953 BUG_ON(entry->val);
954
955 if (move_to_swap_cache(page, swap) == 0) {
956 shmem_swp_set(info, entry, swap.val);
957 shmem_swp_unmap(entry);
958 spin_unlock(&info->lock);
959 if (list_empty(&info->swaplist)) {
960 spin_lock(&shmem_swaplist_lock);
961 /* move instead of add in case we're racing */
962 list_move_tail(&info->swaplist, &shmem_swaplist);
963 spin_unlock(&shmem_swaplist_lock);
964 }
965 unlock_page(page);
966 return 0;
967 }
968
969 shmem_swp_unmap(entry);
970unlock:
971 spin_unlock(&info->lock);
972 swap_free(swap);
973redirty:
974 set_page_dirty(page);
Zach Brown994fc28c2005-12-15 14:28:17 -0800975 return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976}
977
978#ifdef CONFIG_NUMA
Hugh Dickinsd15c0232006-03-22 00:08:46 -0800979static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +0000980{
981 char *nodelist = strchr(value, ':');
982 int err = 1;
983
984 if (nodelist) {
985 /* NUL-terminate policy string */
986 *nodelist++ = '\0';
987 if (nodelist_parse(nodelist, *policy_nodes))
988 goto out;
Lee Schermerhorn37b07e42007-10-16 01:25:39 -0700989 if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY]))
Hugh Dickinsa2109062007-06-08 13:46:46 -0700990 goto out;
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +0000991 }
992 if (!strcmp(value, "default")) {
993 *policy = MPOL_DEFAULT;
994 /* Don't allow a nodelist */
995 if (!nodelist)
996 err = 0;
997 } else if (!strcmp(value, "prefer")) {
998 *policy = MPOL_PREFERRED;
999 /* Insist on a nodelist of one node only */
1000 if (nodelist) {
1001 char *rest = nodelist;
1002 while (isdigit(*rest))
1003 rest++;
1004 if (!*rest)
1005 err = 0;
1006 }
1007 } else if (!strcmp(value, "bind")) {
1008 *policy = MPOL_BIND;
1009 /* Insist on a nodelist */
1010 if (nodelist)
1011 err = 0;
1012 } else if (!strcmp(value, "interleave")) {
1013 *policy = MPOL_INTERLEAVE;
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07001014 /*
1015 * Default to online nodes with memory if no nodelist
1016 */
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001017 if (!nodelist)
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07001018 *policy_nodes = node_states[N_HIGH_MEMORY];
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001019 err = 0;
1020 }
1021out:
1022 /* Restore string for error message */
1023 if (nodelist)
1024 *--nodelist = ':';
1025 return err;
1026}
1027
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028static struct page *shmem_swapin_async(struct shared_policy *p,
1029 swp_entry_t entry, unsigned long idx)
1030{
1031 struct page *page;
1032 struct vm_area_struct pvma;
1033
1034 /* Create a pseudo vma that just contains the policy */
1035 memset(&pvma, 0, sizeof(struct vm_area_struct));
1036 pvma.vm_end = PAGE_SIZE;
1037 pvma.vm_pgoff = idx;
1038 pvma.vm_policy = mpol_shared_policy_lookup(p, idx);
1039 page = read_swap_cache_async(entry, &pvma, 0);
1040 mpol_free(pvma.vm_policy);
1041 return page;
1042}
1043
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001044static struct page *shmem_swapin(struct shmem_inode_info *info,
1045 swp_entry_t entry, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046{
1047 struct shared_policy *p = &info->policy;
1048 int i, num;
1049 struct page *page;
1050 unsigned long offset;
1051
1052 num = valid_swaphandles(entry, &offset);
1053 for (i = 0; i < num; offset++, i++) {
1054 page = shmem_swapin_async(p,
1055 swp_entry(swp_type(entry), offset), idx);
1056 if (!page)
1057 break;
1058 page_cache_release(page);
1059 }
1060 lru_add_drain(); /* Push any new pages onto the LRU now */
1061 return shmem_swapin_async(p, entry, idx);
1062}
1063
1064static struct page *
Al Viro6daa0e22005-10-21 03:18:50 -04001065shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 unsigned long idx)
1067{
1068 struct vm_area_struct pvma;
1069 struct page *page;
1070
1071 memset(&pvma, 0, sizeof(struct vm_area_struct));
1072 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
1073 pvma.vm_pgoff = idx;
1074 pvma.vm_end = PAGE_SIZE;
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001075 page = alloc_page_vma(gfp, &pvma, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076 mpol_free(pvma.vm_policy);
1077 return page;
1078}
1079#else
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07001080static inline int shmem_parse_mpol(char *value, int *policy,
1081 nodemask_t *policy_nodes)
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00001082{
1083 return 1;
1084}
1085
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086static inline struct page *
1087shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
1088{
1089 swapin_readahead(entry, 0, NULL);
1090 return read_swap_cache_async(entry, NULL, 0);
1091}
1092
1093static inline struct page *
Al Virodd0fc662005-10-07 07:46:04 +01001094shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095{
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001096 return alloc_page(gfp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097}
1098#endif
1099
1100/*
1101 * shmem_getpage - either get the page from swap or allocate a new one
1102 *
1103 * If we allocate a new one we do not mark it dirty. That's up to the
1104 * vm. If we swap it in we mark it dirty since we also free the swap
1105 * entry since a page cannot live in both the swap and page cache
1106 */
1107static int shmem_getpage(struct inode *inode, unsigned long idx,
1108 struct page **pagep, enum sgp_type sgp, int *type)
1109{
1110 struct address_space *mapping = inode->i_mapping;
1111 struct shmem_inode_info *info = SHMEM_I(inode);
1112 struct shmem_sb_info *sbinfo;
1113 struct page *filepage = *pagep;
1114 struct page *swappage;
1115 swp_entry_t *entry;
1116 swp_entry_t swap;
1117 int error;
1118
1119 if (idx >= SHMEM_MAX_INDEX)
1120 return -EFBIG;
Nick Piggin54cb8822007-07-19 01:46:59 -07001121
1122 if (type)
Nick Piggin83c54072007-07-19 01:47:05 -07001123 *type = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07001124
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125 /*
1126 * Normally, filepage is NULL on entry, and either found
1127 * uptodate immediately, or allocated and zeroed, or read
1128 * in under swappage, which is then assigned to filepage.
Nick Piggin800d15a2007-10-16 01:25:03 -07001129 * But shmem_readpage and shmem_write_begin pass in a locked
Hugh Dickinsae9764162007-06-04 10:00:39 +02001130 * filepage, which may be found not uptodate by other callers
1131 * too, and may need to be copied from the swappage read in.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 */
1133repeat:
1134 if (!filepage)
1135 filepage = find_lock_page(mapping, idx);
1136 if (filepage && PageUptodate(filepage))
1137 goto done;
1138 error = 0;
1139 if (sgp == SGP_QUICK)
1140 goto failed;
1141
1142 spin_lock(&info->lock);
1143 shmem_recalc_inode(inode);
1144 entry = shmem_swp_alloc(info, idx, sgp);
1145 if (IS_ERR(entry)) {
1146 spin_unlock(&info->lock);
1147 error = PTR_ERR(entry);
1148 goto failed;
1149 }
1150 swap = *entry;
1151
1152 if (swap.val) {
1153 /* Look it up and read it in.. */
1154 swappage = lookup_swap_cache(swap);
1155 if (!swappage) {
1156 shmem_swp_unmap(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157 /* here we actually do the io */
Nick Piggin83c54072007-07-19 01:47:05 -07001158 if (type && !(*type & VM_FAULT_MAJOR)) {
Christoph Lameterf8891e52006-06-30 01:55:45 -07001159 __count_vm_event(PGMAJFAULT);
Nick Piggin83c54072007-07-19 01:47:05 -07001160 *type |= VM_FAULT_MAJOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161 }
Christoph Lameterf8891e52006-06-30 01:55:45 -07001162 spin_unlock(&info->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 swappage = shmem_swapin(info, swap, idx);
1164 if (!swappage) {
1165 spin_lock(&info->lock);
1166 entry = shmem_swp_alloc(info, idx, sgp);
1167 if (IS_ERR(entry))
1168 error = PTR_ERR(entry);
1169 else {
1170 if (entry->val == swap.val)
1171 error = -ENOMEM;
1172 shmem_swp_unmap(entry);
1173 }
1174 spin_unlock(&info->lock);
1175 if (error)
1176 goto failed;
1177 goto repeat;
1178 }
1179 wait_on_page_locked(swappage);
1180 page_cache_release(swappage);
1181 goto repeat;
1182 }
1183
1184 /* We have to do this with page locked to prevent races */
1185 if (TestSetPageLocked(swappage)) {
1186 shmem_swp_unmap(entry);
1187 spin_unlock(&info->lock);
1188 wait_on_page_locked(swappage);
1189 page_cache_release(swappage);
1190 goto repeat;
1191 }
1192 if (PageWriteback(swappage)) {
1193 shmem_swp_unmap(entry);
1194 spin_unlock(&info->lock);
1195 wait_on_page_writeback(swappage);
1196 unlock_page(swappage);
1197 page_cache_release(swappage);
1198 goto repeat;
1199 }
1200 if (!PageUptodate(swappage)) {
1201 shmem_swp_unmap(entry);
1202 spin_unlock(&info->lock);
1203 unlock_page(swappage);
1204 page_cache_release(swappage);
1205 error = -EIO;
1206 goto failed;
1207 }
1208
1209 if (filepage) {
1210 shmem_swp_set(info, entry, 0);
1211 shmem_swp_unmap(entry);
1212 delete_from_swap_cache(swappage);
1213 spin_unlock(&info->lock);
1214 copy_highpage(filepage, swappage);
1215 unlock_page(swappage);
1216 page_cache_release(swappage);
1217 flush_dcache_page(filepage);
1218 SetPageUptodate(filepage);
1219 set_page_dirty(filepage);
1220 swap_free(swap);
1221 } else if (!(error = move_from_swap_cache(
1222 swappage, idx, mapping))) {
1223 info->flags |= SHMEM_PAGEIN;
1224 shmem_swp_set(info, entry, 0);
1225 shmem_swp_unmap(entry);
1226 spin_unlock(&info->lock);
1227 filepage = swappage;
1228 swap_free(swap);
1229 } else {
1230 shmem_swp_unmap(entry);
1231 spin_unlock(&info->lock);
1232 unlock_page(swappage);
1233 page_cache_release(swappage);
1234 if (error == -ENOMEM) {
1235 /* let kswapd refresh zone for GFP_ATOMICs */
Andrew Morton3fcfab12006-10-19 23:28:16 -07001236 congestion_wait(WRITE, HZ/50);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 }
1238 goto repeat;
1239 }
1240 } else if (sgp == SGP_READ && !filepage) {
1241 shmem_swp_unmap(entry);
1242 filepage = find_get_page(mapping, idx);
1243 if (filepage &&
1244 (!PageUptodate(filepage) || TestSetPageLocked(filepage))) {
1245 spin_unlock(&info->lock);
1246 wait_on_page_locked(filepage);
1247 page_cache_release(filepage);
1248 filepage = NULL;
1249 goto repeat;
1250 }
1251 spin_unlock(&info->lock);
1252 } else {
1253 shmem_swp_unmap(entry);
1254 sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001255 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 spin_lock(&sbinfo->stat_lock);
1257 if (sbinfo->free_blocks == 0 ||
1258 shmem_acct_block(info->flags)) {
1259 spin_unlock(&sbinfo->stat_lock);
1260 spin_unlock(&info->lock);
1261 error = -ENOSPC;
1262 goto failed;
1263 }
1264 sbinfo->free_blocks--;
1265 inode->i_blocks += BLOCKS_PER_PAGE;
1266 spin_unlock(&sbinfo->stat_lock);
1267 } else if (shmem_acct_block(info->flags)) {
1268 spin_unlock(&info->lock);
1269 error = -ENOSPC;
1270 goto failed;
1271 }
1272
1273 if (!filepage) {
1274 spin_unlock(&info->lock);
1275 filepage = shmem_alloc_page(mapping_gfp_mask(mapping),
1276 info,
1277 idx);
1278 if (!filepage) {
1279 shmem_unacct_blocks(info->flags, 1);
1280 shmem_free_blocks(inode, 1);
1281 error = -ENOMEM;
1282 goto failed;
1283 }
1284
1285 spin_lock(&info->lock);
1286 entry = shmem_swp_alloc(info, idx, sgp);
1287 if (IS_ERR(entry))
1288 error = PTR_ERR(entry);
1289 else {
1290 swap = *entry;
1291 shmem_swp_unmap(entry);
1292 }
1293 if (error || swap.val || 0 != add_to_page_cache_lru(
1294 filepage, mapping, idx, GFP_ATOMIC)) {
1295 spin_unlock(&info->lock);
1296 page_cache_release(filepage);
1297 shmem_unacct_blocks(info->flags, 1);
1298 shmem_free_blocks(inode, 1);
1299 filepage = NULL;
1300 if (error)
1301 goto failed;
1302 goto repeat;
1303 }
1304 info->flags |= SHMEM_PAGEIN;
1305 }
1306
1307 info->alloced++;
1308 spin_unlock(&info->lock);
Hugh Dickinse84e2e12007-11-28 18:55:10 +00001309 clear_highpage(filepage);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310 flush_dcache_page(filepage);
1311 SetPageUptodate(filepage);
1312 }
1313done:
1314 if (*pagep != filepage) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 *pagep = filepage;
Nick Piggin54cb8822007-07-19 01:46:59 -07001316 if (sgp != SGP_FAULT)
Nick Piggind00806b2007-07-19 01:46:57 -07001317 unlock_page(filepage);
1318
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 }
1320 return 0;
1321
1322failed:
1323 if (*pagep != filepage) {
1324 unlock_page(filepage);
1325 page_cache_release(filepage);
1326 }
1327 return error;
1328}
1329
Nick Piggind0217ac2007-07-19 01:47:03 -07001330static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001332 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 int error;
Nick Piggind0217ac2007-07-19 01:47:03 -07001334 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335
Nick Piggind0217ac2007-07-19 01:47:03 -07001336 if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
1337 return VM_FAULT_SIGBUS;
Nick Piggind00806b2007-07-19 01:46:57 -07001338
Nick Piggind0217ac2007-07-19 01:47:03 -07001339 error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_FAULT, &ret);
1340 if (error)
1341 return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342
Nick Piggind0217ac2007-07-19 01:47:03 -07001343 mark_page_accessed(vmf->page);
Nick Piggin83c54072007-07-19 01:47:05 -07001344 return ret | VM_FAULT_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345}
1346
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347#ifdef CONFIG_NUMA
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001348static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001350 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
1352}
1353
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001354static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
1355 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001357 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358 unsigned long idx;
1359
1360 idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
1361 return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
1362}
1363#endif
1364
1365int shmem_lock(struct file *file, int lock, struct user_struct *user)
1366{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001367 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 struct shmem_inode_info *info = SHMEM_I(inode);
1369 int retval = -ENOMEM;
1370
1371 spin_lock(&info->lock);
1372 if (lock && !(info->flags & VM_LOCKED)) {
1373 if (!user_shm_lock(inode->i_size, user))
1374 goto out_nomem;
1375 info->flags |= VM_LOCKED;
1376 }
1377 if (!lock && (info->flags & VM_LOCKED) && user) {
1378 user_shm_unlock(inode->i_size, user);
1379 info->flags &= ~VM_LOCKED;
1380 }
1381 retval = 0;
1382out_nomem:
1383 spin_unlock(&info->lock);
1384 return retval;
1385}
1386
Adrian Bunk9b83a6a2007-02-28 20:11:03 -08001387static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388{
1389 file_accessed(file);
1390 vma->vm_ops = &shmem_vm_ops;
Nick Piggind0217ac2007-07-19 01:47:03 -07001391 vma->vm_flags |= VM_CAN_NONLINEAR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 return 0;
1393}
1394
1395static struct inode *
1396shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
1397{
1398 struct inode *inode;
1399 struct shmem_inode_info *info;
1400 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
1401
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001402 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001403 spin_lock(&sbinfo->stat_lock);
1404 if (!sbinfo->free_inodes) {
1405 spin_unlock(&sbinfo->stat_lock);
1406 return NULL;
1407 }
1408 sbinfo->free_inodes--;
1409 spin_unlock(&sbinfo->stat_lock);
1410 }
1411
1412 inode = new_inode(sb);
1413 if (inode) {
1414 inode->i_mode = mode;
1415 inode->i_uid = current->fsuid;
1416 inode->i_gid = current->fsgid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 inode->i_blocks = 0;
1418 inode->i_mapping->a_ops = &shmem_aops;
1419 inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
1420 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
David M. Grimes91828a42006-10-17 00:09:45 -07001421 inode->i_generation = get_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422 info = SHMEM_I(inode);
1423 memset(info, 0, (char *)inode - (char *)info);
1424 spin_lock_init(&info->lock);
1425 INIT_LIST_HEAD(&info->swaplist);
1426
1427 switch (mode & S_IFMT) {
1428 default:
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001429 inode->i_op = &shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 init_special_inode(inode, mode, dev);
1431 break;
1432 case S_IFREG:
1433 inode->i_op = &shmem_inode_operations;
1434 inode->i_fop = &shmem_file_operations;
Robin Holt7339ff82006-01-14 13:20:48 -08001435 mpol_shared_policy_init(&info->policy, sbinfo->policy,
1436 &sbinfo->policy_nodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437 break;
1438 case S_IFDIR:
Dave Hansend8c76e62006-09-30 23:29:04 -07001439 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440 /* Some things misbehave if size == 0 on a directory */
1441 inode->i_size = 2 * BOGO_DIRENT_SIZE;
1442 inode->i_op = &shmem_dir_inode_operations;
1443 inode->i_fop = &simple_dir_operations;
1444 break;
1445 case S_IFLNK:
1446 /*
1447 * Must not load anything in the rbtree,
1448 * mpol_free_shared_policy will not be called.
1449 */
Robin Holt7339ff82006-01-14 13:20:48 -08001450 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT,
1451 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452 break;
1453 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001454 } else if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001455 spin_lock(&sbinfo->stat_lock);
1456 sbinfo->free_inodes++;
1457 spin_unlock(&sbinfo->stat_lock);
1458 }
1459 return inode;
1460}
1461
1462#ifdef CONFIG_TMPFS
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001463static const struct inode_operations shmem_symlink_inode_operations;
1464static const struct inode_operations shmem_symlink_inline_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465
1466/*
Nick Piggin800d15a2007-10-16 01:25:03 -07001467 * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin;
Hugh Dickinsae9764162007-06-04 10:00:39 +02001468 * but providing them allows a tmpfs file to be used for splice, sendfile, and
1469 * below the loop driver, in the generic fashion that many filesystems support.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470 */
Hugh Dickinsae9764162007-06-04 10:00:39 +02001471static int shmem_readpage(struct file *file, struct page *page)
1472{
1473 struct inode *inode = page->mapping->host;
1474 int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL);
1475 unlock_page(page);
1476 return error;
1477}
1478
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479static int
Nick Piggin800d15a2007-10-16 01:25:03 -07001480shmem_write_begin(struct file *file, struct address_space *mapping,
1481 loff_t pos, unsigned len, unsigned flags,
1482 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483{
Nick Piggin800d15a2007-10-16 01:25:03 -07001484 struct inode *inode = mapping->host;
1485 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1486 *pagep = NULL;
1487 return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL);
1488}
1489
1490static int
1491shmem_write_end(struct file *file, struct address_space *mapping,
1492 loff_t pos, unsigned len, unsigned copied,
1493 struct page *page, void *fsdata)
1494{
1495 struct inode *inode = mapping->host;
1496
1497 set_page_dirty(page);
1498 page_cache_release(page);
1499
1500 if (pos+copied > inode->i_size)
1501 i_size_write(inode, pos+copied);
1502
1503 return copied;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504}
1505
1506static ssize_t
1507shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
1508{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001509 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 loff_t pos;
1511 unsigned long written;
1512 ssize_t err;
1513
1514 if ((ssize_t) count < 0)
1515 return -EINVAL;
1516
1517 if (!access_ok(VERIFY_READ, buf, count))
1518 return -EFAULT;
1519
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001520 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521
1522 pos = *ppos;
1523 written = 0;
1524
1525 err = generic_write_checks(file, &pos, &count, 0);
1526 if (err || !count)
1527 goto out;
1528
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001529 err = remove_suid(file->f_path.dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 if (err)
1531 goto out;
1532
1533 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
1534
1535 do {
1536 struct page *page = NULL;
1537 unsigned long bytes, index, offset;
1538 char *kaddr;
1539 int left;
1540
1541 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
1542 index = pos >> PAGE_CACHE_SHIFT;
1543 bytes = PAGE_CACHE_SIZE - offset;
1544 if (bytes > count)
1545 bytes = count;
1546
1547 /*
1548 * We don't hold page lock across copy from user -
1549 * what would it guard against? - so no deadlock here.
1550 * But it still may be a good idea to prefault below.
1551 */
1552
1553 err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL);
1554 if (err)
1555 break;
1556
1557 left = bytes;
1558 if (PageHighMem(page)) {
1559 volatile unsigned char dummy;
1560 __get_user(dummy, buf);
1561 __get_user(dummy, buf + bytes - 1);
1562
1563 kaddr = kmap_atomic(page, KM_USER0);
1564 left = __copy_from_user_inatomic(kaddr + offset,
1565 buf, bytes);
1566 kunmap_atomic(kaddr, KM_USER0);
1567 }
1568 if (left) {
1569 kaddr = kmap(page);
1570 left = __copy_from_user(kaddr + offset, buf, bytes);
1571 kunmap(page);
1572 }
1573
1574 written += bytes;
1575 count -= bytes;
1576 pos += bytes;
1577 buf += bytes;
1578 if (pos > inode->i_size)
1579 i_size_write(inode, pos);
1580
1581 flush_dcache_page(page);
1582 set_page_dirty(page);
1583 mark_page_accessed(page);
1584 page_cache_release(page);
1585
1586 if (left) {
1587 pos -= left;
1588 written -= left;
1589 err = -EFAULT;
1590 break;
1591 }
1592
1593 /*
1594 * Our dirty pages are not counted in nr_dirty,
1595 * and we do not attempt to balance dirty pages.
1596 */
1597
1598 cond_resched();
1599 } while (count);
1600
1601 *ppos = pos;
1602 if (written)
1603 err = written;
1604out:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001605 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606 return err;
1607}
1608
1609static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
1610{
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001611 struct inode *inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612 struct address_space *mapping = inode->i_mapping;
1613 unsigned long index, offset;
1614
1615 index = *ppos >> PAGE_CACHE_SHIFT;
1616 offset = *ppos & ~PAGE_CACHE_MASK;
1617
1618 for (;;) {
1619 struct page *page = NULL;
1620 unsigned long end_index, nr, ret;
1621 loff_t i_size = i_size_read(inode);
1622
1623 end_index = i_size >> PAGE_CACHE_SHIFT;
1624 if (index > end_index)
1625 break;
1626 if (index == end_index) {
1627 nr = i_size & ~PAGE_CACHE_MASK;
1628 if (nr <= offset)
1629 break;
1630 }
1631
1632 desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL);
1633 if (desc->error) {
1634 if (desc->error == -EINVAL)
1635 desc->error = 0;
1636 break;
1637 }
1638
1639 /*
1640 * We must evaluate after, since reads (unlike writes)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001641 * are called without i_mutex protection against truncate
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642 */
1643 nr = PAGE_CACHE_SIZE;
1644 i_size = i_size_read(inode);
1645 end_index = i_size >> PAGE_CACHE_SHIFT;
1646 if (index == end_index) {
1647 nr = i_size & ~PAGE_CACHE_MASK;
1648 if (nr <= offset) {
1649 if (page)
1650 page_cache_release(page);
1651 break;
1652 }
1653 }
1654 nr -= offset;
1655
1656 if (page) {
1657 /*
1658 * If users can be writing to this page using arbitrary
1659 * virtual addresses, take care about potential aliasing
1660 * before reading the page on the kernel side.
1661 */
1662 if (mapping_writably_mapped(mapping))
1663 flush_dcache_page(page);
1664 /*
1665 * Mark the page accessed if we read the beginning.
1666 */
1667 if (!offset)
1668 mark_page_accessed(page);
Nick Pigginb5810032005-10-29 18:16:12 -07001669 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 page = ZERO_PAGE(0);
Nick Pigginb5810032005-10-29 18:16:12 -07001671 page_cache_get(page);
1672 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673
1674 /*
1675 * Ok, we have the page, and it's up-to-date, so
1676 * now we can copy it to user space...
1677 *
1678 * The actor routine returns how many bytes were actually used..
1679 * NOTE! This may not be the same as how much of a user buffer
1680 * we filled up (we may be padding etc), so we can only update
1681 * "pos" here (the actor routine has to update the user buffer
1682 * pointers and the remaining count).
1683 */
1684 ret = actor(desc, page, offset, nr);
1685 offset += ret;
1686 index += offset >> PAGE_CACHE_SHIFT;
1687 offset &= ~PAGE_CACHE_MASK;
1688
1689 page_cache_release(page);
1690 if (ret != nr || !desc->count)
1691 break;
1692
1693 cond_resched();
1694 }
1695
1696 *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
1697 file_accessed(filp);
1698}
1699
1700static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
1701{
1702 read_descriptor_t desc;
1703
1704 if ((ssize_t) count < 0)
1705 return -EINVAL;
1706 if (!access_ok(VERIFY_WRITE, buf, count))
1707 return -EFAULT;
1708 if (!count)
1709 return 0;
1710
1711 desc.written = 0;
1712 desc.count = count;
1713 desc.arg.buf = buf;
1714 desc.error = 0;
1715
1716 do_shmem_file_read(filp, ppos, &desc, file_read_actor);
1717 if (desc.written)
1718 return desc.written;
1719 return desc.error;
1720}
1721
David Howells726c3342006-06-23 02:02:58 -07001722static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723{
David Howells726c3342006-06-23 02:02:58 -07001724 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725
1726 buf->f_type = TMPFS_MAGIC;
1727 buf->f_bsize = PAGE_CACHE_SIZE;
1728 buf->f_namelen = NAME_MAX;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001729 spin_lock(&sbinfo->stat_lock);
1730 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731 buf->f_blocks = sbinfo->max_blocks;
1732 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001733 }
1734 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735 buf->f_files = sbinfo->max_inodes;
1736 buf->f_ffree = sbinfo->free_inodes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 }
1738 /* else leave those fields 0 like simple_statfs */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001739 spin_unlock(&sbinfo->stat_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 return 0;
1741}
1742
1743/*
1744 * File creation. Allocate an inode, and we're done..
1745 */
1746static int
1747shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1748{
1749 struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev);
1750 int error = -ENOSPC;
1751
1752 if (inode) {
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001753 error = security_inode_init_security(inode, dir, NULL, NULL,
1754 NULL);
1755 if (error) {
1756 if (error != -EOPNOTSUPP) {
1757 iput(inode);
1758 return error;
1759 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001760 }
1761 error = shmem_acl_init(inode, dir);
1762 if (error) {
1763 iput(inode);
1764 return error;
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001765 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001766 if (dir->i_mode & S_ISGID) {
1767 inode->i_gid = dir->i_gid;
1768 if (S_ISDIR(mode))
1769 inode->i_mode |= S_ISGID;
1770 }
1771 dir->i_size += BOGO_DIRENT_SIZE;
1772 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1773 d_instantiate(dentry, inode);
1774 dget(dentry); /* Extra count - pin the dentry in core */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 }
1776 return error;
1777}
1778
1779static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1780{
1781 int error;
1782
1783 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
1784 return error;
Dave Hansend8c76e62006-09-30 23:29:04 -07001785 inc_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 return 0;
1787}
1788
1789static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
1790 struct nameidata *nd)
1791{
1792 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
1793}
1794
1795/*
1796 * Link a file..
1797 */
1798static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1799{
1800 struct inode *inode = old_dentry->d_inode;
1801 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
1802
1803 /*
1804 * No ordinary (disk based) filesystem counts links as inodes;
1805 * but each new link needs a new dentry, pinning lowmem, and
1806 * tmpfs dentries cannot be pruned until they are unlinked.
1807 */
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001808 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 spin_lock(&sbinfo->stat_lock);
1810 if (!sbinfo->free_inodes) {
1811 spin_unlock(&sbinfo->stat_lock);
1812 return -ENOSPC;
1813 }
1814 sbinfo->free_inodes--;
1815 spin_unlock(&sbinfo->stat_lock);
1816 }
1817
1818 dir->i_size += BOGO_DIRENT_SIZE;
1819 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -07001820 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 atomic_inc(&inode->i_count); /* New dentry reference */
1822 dget(dentry); /* Extra pinning count for the created dentry */
1823 d_instantiate(dentry, inode);
1824 return 0;
1825}
1826
1827static int shmem_unlink(struct inode *dir, struct dentry *dentry)
1828{
1829 struct inode *inode = dentry->d_inode;
1830
1831 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) {
1832 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001833 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 spin_lock(&sbinfo->stat_lock);
1835 sbinfo->free_inodes++;
1836 spin_unlock(&sbinfo->stat_lock);
1837 }
1838 }
1839
1840 dir->i_size -= BOGO_DIRENT_SIZE;
1841 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001842 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843 dput(dentry); /* Undo the count from "create" - this does all the work */
1844 return 0;
1845}
1846
1847static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
1848{
1849 if (!simple_empty(dentry))
1850 return -ENOTEMPTY;
1851
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001852 drop_nlink(dentry->d_inode);
1853 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 return shmem_unlink(dir, dentry);
1855}
1856
1857/*
1858 * The VFS layer already does all the dentry stuff for rename,
1859 * we just have to decrement the usage count for the target if
1860 * it exists so that the VFS layer correctly free's it when it
1861 * gets overwritten.
1862 */
1863static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
1864{
1865 struct inode *inode = old_dentry->d_inode;
1866 int they_are_dirs = S_ISDIR(inode->i_mode);
1867
1868 if (!simple_empty(new_dentry))
1869 return -ENOTEMPTY;
1870
1871 if (new_dentry->d_inode) {
1872 (void) shmem_unlink(new_dir, new_dentry);
1873 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001874 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -07001876 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -07001877 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878 }
1879
1880 old_dir->i_size -= BOGO_DIRENT_SIZE;
1881 new_dir->i_size += BOGO_DIRENT_SIZE;
1882 old_dir->i_ctime = old_dir->i_mtime =
1883 new_dir->i_ctime = new_dir->i_mtime =
1884 inode->i_ctime = CURRENT_TIME;
1885 return 0;
1886}
1887
1888static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1889{
1890 int error;
1891 int len;
1892 struct inode *inode;
1893 struct page *page = NULL;
1894 char *kaddr;
1895 struct shmem_inode_info *info;
1896
1897 len = strlen(symname) + 1;
1898 if (len > PAGE_CACHE_SIZE)
1899 return -ENAMETOOLONG;
1900
1901 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
1902 if (!inode)
1903 return -ENOSPC;
1904
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001905 error = security_inode_init_security(inode, dir, NULL, NULL,
1906 NULL);
1907 if (error) {
1908 if (error != -EOPNOTSUPP) {
1909 iput(inode);
1910 return error;
1911 }
1912 error = 0;
1913 }
1914
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915 info = SHMEM_I(inode);
1916 inode->i_size = len-1;
1917 if (len <= (char *)inode - (char *)info) {
1918 /* do it inline */
1919 memcpy(info, symname, len);
1920 inode->i_op = &shmem_symlink_inline_operations;
1921 } else {
1922 error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
1923 if (error) {
1924 iput(inode);
1925 return error;
1926 }
1927 inode->i_op = &shmem_symlink_inode_operations;
1928 kaddr = kmap_atomic(page, KM_USER0);
1929 memcpy(kaddr, symname, len);
1930 kunmap_atomic(kaddr, KM_USER0);
1931 set_page_dirty(page);
1932 page_cache_release(page);
1933 }
1934 if (dir->i_mode & S_ISGID)
1935 inode->i_gid = dir->i_gid;
1936 dir->i_size += BOGO_DIRENT_SIZE;
1937 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1938 d_instantiate(dentry, inode);
1939 dget(dentry);
1940 return 0;
1941}
1942
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001943static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944{
1945 nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001946 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001947}
1948
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001949static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950{
1951 struct page *page = NULL;
1952 int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
1953 nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001954 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955}
1956
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001957static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958{
1959 if (!IS_ERR(nd_get_link(nd))) {
Linus Torvaldscc314ee2005-08-19 18:02:56 -07001960 struct page *page = cookie;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001961 kunmap(page);
1962 mark_page_accessed(page);
1963 page_cache_release(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964 }
1965}
1966
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001967static const struct inode_operations shmem_symlink_inline_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001968 .readlink = generic_readlink,
1969 .follow_link = shmem_follow_link_inline,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970};
1971
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001972static const struct inode_operations shmem_symlink_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 .truncate = shmem_truncate,
1974 .readlink = generic_readlink,
1975 .follow_link = shmem_follow_link,
1976 .put_link = shmem_put_link,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977};
1978
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001979#ifdef CONFIG_TMPFS_POSIX_ACL
1980/**
1981 * Superblocks without xattr inode operations will get security.* xattr
1982 * support from the VFS "for free". As soon as we have any other xattrs
1983 * like ACLs, we also need to implement the security.* handlers at
1984 * filesystem level, though.
1985 */
1986
1987static size_t shmem_xattr_security_list(struct inode *inode, char *list,
1988 size_t list_len, const char *name,
1989 size_t name_len)
1990{
1991 return security_inode_listsecurity(inode, list, list_len);
1992}
1993
1994static int shmem_xattr_security_get(struct inode *inode, const char *name,
1995 void *buffer, size_t size)
1996{
1997 if (strcmp(name, "") == 0)
1998 return -EINVAL;
1999 return security_inode_getsecurity(inode, name, buffer, size,
2000 -EOPNOTSUPP);
2001}
2002
2003static int shmem_xattr_security_set(struct inode *inode, const char *name,
2004 const void *value, size_t size, int flags)
2005{
2006 if (strcmp(name, "") == 0)
2007 return -EINVAL;
2008 return security_inode_setsecurity(inode, name, value, size, flags);
2009}
2010
Adrian Bunk1f370a22006-12-06 20:38:21 -08002011static struct xattr_handler shmem_xattr_security_handler = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002012 .prefix = XATTR_SECURITY_PREFIX,
2013 .list = shmem_xattr_security_list,
2014 .get = shmem_xattr_security_get,
2015 .set = shmem_xattr_security_set,
2016};
2017
2018static struct xattr_handler *shmem_xattr_handlers[] = {
2019 &shmem_xattr_acl_access_handler,
2020 &shmem_xattr_acl_default_handler,
2021 &shmem_xattr_security_handler,
2022 NULL
2023};
2024#endif
2025
David M. Grimes91828a42006-10-17 00:09:45 -07002026static struct dentry *shmem_get_parent(struct dentry *child)
2027{
2028 return ERR_PTR(-ESTALE);
2029}
2030
2031static int shmem_match(struct inode *ino, void *vfh)
2032{
2033 __u32 *fh = vfh;
2034 __u64 inum = fh[2];
2035 inum = (inum << 32) | fh[1];
2036 return ino->i_ino == inum && fh[0] == ino->i_generation;
2037}
2038
Christoph Hellwig480b1162007-10-21 16:42:13 -07002039static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
2040 struct fid *fid, int fh_len, int fh_type)
David M. Grimes91828a42006-10-17 00:09:45 -07002041{
David M. Grimes91828a42006-10-17 00:09:45 -07002042 struct inode *inode;
Christoph Hellwig480b1162007-10-21 16:42:13 -07002043 struct dentry *dentry = NULL;
2044 u64 inum = fid->raw[2];
2045 inum = (inum << 32) | fid->raw[1];
David M. Grimes91828a42006-10-17 00:09:45 -07002046
Christoph Hellwig480b1162007-10-21 16:42:13 -07002047 if (fh_len < 3)
2048 return NULL;
2049
2050 inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
2051 shmem_match, fid->raw);
David M. Grimes91828a42006-10-17 00:09:45 -07002052 if (inode) {
Christoph Hellwig480b1162007-10-21 16:42:13 -07002053 dentry = d_find_alias(inode);
David M. Grimes91828a42006-10-17 00:09:45 -07002054 iput(inode);
2055 }
2056
Christoph Hellwig480b1162007-10-21 16:42:13 -07002057 return dentry;
David M. Grimes91828a42006-10-17 00:09:45 -07002058}
2059
2060static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
2061 int connectable)
2062{
2063 struct inode *inode = dentry->d_inode;
2064
2065 if (*len < 3)
2066 return 255;
2067
2068 if (hlist_unhashed(&inode->i_hash)) {
2069 /* Unfortunately insert_inode_hash is not idempotent,
2070 * so as we hash inodes here rather than at creation
2071 * time, we need a lock to ensure we only try
2072 * to do it once
2073 */
2074 static DEFINE_SPINLOCK(lock);
2075 spin_lock(&lock);
2076 if (hlist_unhashed(&inode->i_hash))
2077 __insert_inode_hash(inode,
2078 inode->i_ino + inode->i_generation);
2079 spin_unlock(&lock);
2080 }
2081
2082 fh[0] = inode->i_generation;
2083 fh[1] = inode->i_ino;
2084 fh[2] = ((__u64)inode->i_ino) >> 32;
2085
2086 *len = 3;
2087 return 1;
2088}
2089
Christoph Hellwig39655162007-10-21 16:42:17 -07002090static const struct export_operations shmem_export_ops = {
David M. Grimes91828a42006-10-17 00:09:45 -07002091 .get_parent = shmem_get_parent,
David M. Grimes91828a42006-10-17 00:09:45 -07002092 .encode_fh = shmem_encode_fh,
Christoph Hellwig480b1162007-10-21 16:42:13 -07002093 .fh_to_dentry = shmem_fh_to_dentry,
David M. Grimes91828a42006-10-17 00:09:45 -07002094};
2095
Robin Holt7339ff82006-01-14 13:20:48 -08002096static int shmem_parse_options(char *options, int *mode, uid_t *uid,
2097 gid_t *gid, unsigned long *blocks, unsigned long *inodes,
2098 int *policy, nodemask_t *policy_nodes)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099{
2100 char *this_char, *value, *rest;
2101
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002102 while (options != NULL) {
2103 this_char = options;
2104 for (;;) {
2105 /*
2106 * NUL-terminate this option: unfortunately,
2107 * mount options form a comma-separated list,
2108 * but mpol's nodelist may also contain commas.
2109 */
2110 options = strchr(options, ',');
2111 if (options == NULL)
2112 break;
2113 options++;
2114 if (!isdigit(*options)) {
2115 options[-1] = '\0';
2116 break;
2117 }
2118 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002119 if (!*this_char)
2120 continue;
2121 if ((value = strchr(this_char,'=')) != NULL) {
2122 *value++ = 0;
2123 } else {
2124 printk(KERN_ERR
2125 "tmpfs: No value for mount option '%s'\n",
2126 this_char);
2127 return 1;
2128 }
2129
2130 if (!strcmp(this_char,"size")) {
2131 unsigned long long size;
2132 size = memparse(value,&rest);
2133 if (*rest == '%') {
2134 size <<= PAGE_SHIFT;
2135 size *= totalram_pages;
2136 do_div(size, 100);
2137 rest++;
2138 }
2139 if (*rest)
2140 goto bad_val;
2141 *blocks = size >> PAGE_CACHE_SHIFT;
2142 } else if (!strcmp(this_char,"nr_blocks")) {
2143 *blocks = memparse(value,&rest);
2144 if (*rest)
2145 goto bad_val;
2146 } else if (!strcmp(this_char,"nr_inodes")) {
2147 *inodes = memparse(value,&rest);
2148 if (*rest)
2149 goto bad_val;
2150 } else if (!strcmp(this_char,"mode")) {
2151 if (!mode)
2152 continue;
2153 *mode = simple_strtoul(value,&rest,8);
2154 if (*rest)
2155 goto bad_val;
2156 } else if (!strcmp(this_char,"uid")) {
2157 if (!uid)
2158 continue;
2159 *uid = simple_strtoul(value,&rest,0);
2160 if (*rest)
2161 goto bad_val;
2162 } else if (!strcmp(this_char,"gid")) {
2163 if (!gid)
2164 continue;
2165 *gid = simple_strtoul(value,&rest,0);
2166 if (*rest)
2167 goto bad_val;
Robin Holt7339ff82006-01-14 13:20:48 -08002168 } else if (!strcmp(this_char,"mpol")) {
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002169 if (shmem_parse_mpol(value,policy,policy_nodes))
Robin Holt7339ff82006-01-14 13:20:48 -08002170 goto bad_val;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171 } else {
2172 printk(KERN_ERR "tmpfs: Bad mount option %s\n",
2173 this_char);
2174 return 1;
2175 }
2176 }
2177 return 0;
2178
2179bad_val:
2180 printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
2181 value, this_char);
2182 return 1;
2183
2184}
2185
2186static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
2187{
2188 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002189 unsigned long max_blocks = sbinfo->max_blocks;
2190 unsigned long max_inodes = sbinfo->max_inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002191 int policy = sbinfo->policy;
2192 nodemask_t policy_nodes = sbinfo->policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002193 unsigned long blocks;
2194 unsigned long inodes;
2195 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002196
Robin Holt7339ff82006-01-14 13:20:48 -08002197 if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks,
2198 &max_inodes, &policy, &policy_nodes))
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002199 return error;
2200
2201 spin_lock(&sbinfo->stat_lock);
2202 blocks = sbinfo->max_blocks - sbinfo->free_blocks;
2203 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
2204 if (max_blocks < blocks)
2205 goto out;
2206 if (max_inodes < inodes)
2207 goto out;
2208 /*
2209 * Those tests also disallow limited->unlimited while any are in
2210 * use, so i_blocks will always be zero when max_blocks is zero;
2211 * but we must separately disallow unlimited->limited, because
2212 * in that case we have no record of how much is already in use.
2213 */
2214 if (max_blocks && !sbinfo->max_blocks)
2215 goto out;
2216 if (max_inodes && !sbinfo->max_inodes)
2217 goto out;
2218
2219 error = 0;
2220 sbinfo->max_blocks = max_blocks;
2221 sbinfo->free_blocks = max_blocks - blocks;
2222 sbinfo->max_inodes = max_inodes;
2223 sbinfo->free_inodes = max_inodes - inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002224 sbinfo->policy = policy;
2225 sbinfo->policy_nodes = policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002226out:
2227 spin_unlock(&sbinfo->stat_lock);
2228 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002229}
2230#endif
2231
2232static void shmem_put_super(struct super_block *sb)
2233{
2234 kfree(sb->s_fs_info);
2235 sb->s_fs_info = NULL;
2236}
2237
Linus Torvalds1da177e2005-04-16 15:20:36 -07002238static int shmem_fill_super(struct super_block *sb,
2239 void *data, int silent)
2240{
2241 struct inode *inode;
2242 struct dentry *root;
2243 int mode = S_IRWXUGO | S_ISVTX;
2244 uid_t uid = current->fsuid;
2245 gid_t gid = current->fsgid;
2246 int err = -ENOMEM;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002247 struct shmem_sb_info *sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002248 unsigned long blocks = 0;
2249 unsigned long inodes = 0;
Robin Holt7339ff82006-01-14 13:20:48 -08002250 int policy = MPOL_DEFAULT;
Lee Schermerhorn37b07e42007-10-16 01:25:39 -07002251 nodemask_t policy_nodes = node_states[N_HIGH_MEMORY];
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002253#ifdef CONFIG_TMPFS
Linus Torvalds1da177e2005-04-16 15:20:36 -07002254 /*
2255 * Per default we only allow half of the physical ram per
2256 * tmpfs instance, limiting inodes to one per page of lowmem;
2257 * but the internal instance is left unlimited.
2258 */
2259 if (!(sb->s_flags & MS_NOUSER)) {
2260 blocks = totalram_pages / 2;
2261 inodes = totalram_pages - totalhigh_pages;
2262 if (inodes > blocks)
2263 inodes = blocks;
Robin Holt7339ff82006-01-14 13:20:48 -08002264 if (shmem_parse_options(data, &mode, &uid, &gid, &blocks,
2265 &inodes, &policy, &policy_nodes))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002266 return -EINVAL;
2267 }
David M. Grimes91828a42006-10-17 00:09:45 -07002268 sb->s_export_op = &shmem_export_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002269#else
2270 sb->s_flags |= MS_NOUSER;
2271#endif
2272
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002273 /* Round up to L1_CACHE_BYTES to resist false sharing */
2274 sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
2275 L1_CACHE_BYTES), GFP_KERNEL);
2276 if (!sbinfo)
2277 return -ENOMEM;
2278
2279 spin_lock_init(&sbinfo->stat_lock);
2280 sbinfo->max_blocks = blocks;
2281 sbinfo->free_blocks = blocks;
2282 sbinfo->max_inodes = inodes;
2283 sbinfo->free_inodes = inodes;
Robin Holt7339ff82006-01-14 13:20:48 -08002284 sbinfo->policy = policy;
2285 sbinfo->policy_nodes = policy_nodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002286
2287 sb->s_fs_info = sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002288 sb->s_maxbytes = SHMEM_MAX_BYTES;
2289 sb->s_blocksize = PAGE_CACHE_SIZE;
2290 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2291 sb->s_magic = TMPFS_MAGIC;
2292 sb->s_op = &shmem_ops;
Robin H. Johnsoncfd95a92006-06-12 21:50:25 +01002293 sb->s_time_gran = 1;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002294#ifdef CONFIG_TMPFS_POSIX_ACL
2295 sb->s_xattr = shmem_xattr_handlers;
2296 sb->s_flags |= MS_POSIXACL;
2297#endif
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002298
Linus Torvalds1da177e2005-04-16 15:20:36 -07002299 inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
2300 if (!inode)
2301 goto failed;
2302 inode->i_uid = uid;
2303 inode->i_gid = gid;
2304 root = d_alloc_root(inode);
2305 if (!root)
2306 goto failed_iput;
2307 sb->s_root = root;
2308 return 0;
2309
2310failed_iput:
2311 iput(inode);
2312failed:
2313 shmem_put_super(sb);
2314 return err;
2315}
2316
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002317static struct kmem_cache *shmem_inode_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318
2319static struct inode *shmem_alloc_inode(struct super_block *sb)
2320{
2321 struct shmem_inode_info *p;
Christoph Lametere94b1762006-12-06 20:33:17 -08002322 p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002323 if (!p)
2324 return NULL;
2325 return &p->vfs_inode;
2326}
2327
2328static void shmem_destroy_inode(struct inode *inode)
2329{
2330 if ((inode->i_mode & S_IFMT) == S_IFREG) {
2331 /* only struct inode is valid if it's an inline symlink */
2332 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
2333 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002334 shmem_acl_destroy_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002335 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
2336}
2337
Christoph Lameter4ba9b9d2007-10-16 23:25:51 -07002338static void init_once(struct kmem_cache *cachep, void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002339{
2340 struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
2341
Christoph Lametera35afb82007-05-16 22:10:57 -07002342 inode_init_once(&p->vfs_inode);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002343#ifdef CONFIG_TMPFS_POSIX_ACL
Christoph Lametera35afb82007-05-16 22:10:57 -07002344 p->i_acl = NULL;
2345 p->i_default_acl = NULL;
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002346#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002347}
2348
2349static int init_inodecache(void)
2350{
2351 shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
2352 sizeof(struct shmem_inode_info),
Alexey Dobriyan040b5c62007-10-16 23:26:10 -07002353 0, SLAB_PANIC, init_once);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002354 return 0;
2355}
2356
2357static void destroy_inodecache(void)
2358{
Alexey Dobriyan1a1d92c2006-09-27 01:49:40 -07002359 kmem_cache_destroy(shmem_inode_cachep);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002360}
2361
Christoph Hellwigf5e54d62006-06-28 04:26:44 -07002362static const struct address_space_operations shmem_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002363 .writepage = shmem_writepage,
Ken Chen76719322007-02-10 01:43:15 -08002364 .set_page_dirty = __set_page_dirty_no_writeback,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365#ifdef CONFIG_TMPFS
Hugh Dickinsae9764162007-06-04 10:00:39 +02002366 .readpage = shmem_readpage,
Nick Piggin800d15a2007-10-16 01:25:03 -07002367 .write_begin = shmem_write_begin,
2368 .write_end = shmem_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369#endif
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -07002370 .migratepage = migrate_page,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002371};
2372
Helge Deller15ad7cd2006-12-06 20:40:36 -08002373static const struct file_operations shmem_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002374 .mmap = shmem_mmap,
2375#ifdef CONFIG_TMPFS
2376 .llseek = generic_file_llseek,
2377 .read = shmem_file_read,
2378 .write = shmem_file_write,
2379 .fsync = simple_sync_file,
Hugh Dickinsae9764162007-06-04 10:00:39 +02002380 .splice_read = generic_file_splice_read,
2381 .splice_write = generic_file_splice_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002382#endif
2383};
2384
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002385static const struct inode_operations shmem_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002386 .truncate = shmem_truncate,
2387 .setattr = shmem_notify_change,
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002388 .truncate_range = shmem_truncate_range,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002389#ifdef CONFIG_TMPFS_POSIX_ACL
2390 .setxattr = generic_setxattr,
2391 .getxattr = generic_getxattr,
2392 .listxattr = generic_listxattr,
2393 .removexattr = generic_removexattr,
2394 .permission = shmem_permission,
2395#endif
2396
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397};
2398
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002399static const struct inode_operations shmem_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002400#ifdef CONFIG_TMPFS
2401 .create = shmem_create,
2402 .lookup = simple_lookup,
2403 .link = shmem_link,
2404 .unlink = shmem_unlink,
2405 .symlink = shmem_symlink,
2406 .mkdir = shmem_mkdir,
2407 .rmdir = shmem_rmdir,
2408 .mknod = shmem_mknod,
2409 .rename = shmem_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002410#endif
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002411#ifdef CONFIG_TMPFS_POSIX_ACL
2412 .setattr = shmem_notify_change,
2413 .setxattr = generic_setxattr,
2414 .getxattr = generic_getxattr,
2415 .listxattr = generic_listxattr,
2416 .removexattr = generic_removexattr,
2417 .permission = shmem_permission,
2418#endif
2419};
2420
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002421static const struct inode_operations shmem_special_inode_operations = {
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002422#ifdef CONFIG_TMPFS_POSIX_ACL
2423 .setattr = shmem_notify_change,
2424 .setxattr = generic_setxattr,
2425 .getxattr = generic_getxattr,
2426 .listxattr = generic_listxattr,
2427 .removexattr = generic_removexattr,
2428 .permission = shmem_permission,
2429#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002430};
2431
Hugh Dickins759b9772007-03-05 00:30:28 -08002432static const struct super_operations shmem_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002433 .alloc_inode = shmem_alloc_inode,
2434 .destroy_inode = shmem_destroy_inode,
2435#ifdef CONFIG_TMPFS
2436 .statfs = shmem_statfs,
2437 .remount_fs = shmem_remount_fs,
2438#endif
2439 .delete_inode = shmem_delete_inode,
2440 .drop_inode = generic_delete_inode,
2441 .put_super = shmem_put_super,
2442};
2443
2444static struct vm_operations_struct shmem_vm_ops = {
Nick Piggin54cb8822007-07-19 01:46:59 -07002445 .fault = shmem_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002446#ifdef CONFIG_NUMA
2447 .set_policy = shmem_set_policy,
2448 .get_policy = shmem_get_policy,
2449#endif
2450};
2451
2452
David Howells454e2392006-06-23 02:02:57 -07002453static int shmem_get_sb(struct file_system_type *fs_type,
2454 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455{
David Howells454e2392006-06-23 02:02:57 -07002456 return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002457}
2458
2459static struct file_system_type tmpfs_fs_type = {
2460 .owner = THIS_MODULE,
2461 .name = "tmpfs",
2462 .get_sb = shmem_get_sb,
2463 .kill_sb = kill_litter_super,
2464};
2465static struct vfsmount *shm_mnt;
2466
2467static int __init init_tmpfs(void)
2468{
2469 int error;
2470
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -07002471 error = bdi_init(&shmem_backing_dev_info);
2472 if (error)
2473 goto out4;
2474
Linus Torvalds1da177e2005-04-16 15:20:36 -07002475 error = init_inodecache();
2476 if (error)
2477 goto out3;
2478
2479 error = register_filesystem(&tmpfs_fs_type);
2480 if (error) {
2481 printk(KERN_ERR "Could not register tmpfs\n");
2482 goto out2;
2483 }
Greg Kroah-Hartman95dc1122005-06-20 21:15:16 -07002484
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -04002485 shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002486 tmpfs_fs_type.name, NULL);
2487 if (IS_ERR(shm_mnt)) {
2488 error = PTR_ERR(shm_mnt);
2489 printk(KERN_ERR "Could not kern_mount tmpfs\n");
2490 goto out1;
2491 }
2492 return 0;
2493
2494out1:
2495 unregister_filesystem(&tmpfs_fs_type);
2496out2:
2497 destroy_inodecache();
2498out3:
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -07002499 bdi_destroy(&shmem_backing_dev_info);
2500out4:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002501 shm_mnt = ERR_PTR(error);
2502 return error;
2503}
2504module_init(init_tmpfs)
2505
2506/*
2507 * shmem_file_setup - get an unlinked file living in tmpfs
2508 *
2509 * @name: name for dentry (to be seen in /proc/<pid>/maps
2510 * @size: size to be set for the file
2511 *
2512 */
2513struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
2514{
2515 int error;
2516 struct file *file;
2517 struct inode *inode;
2518 struct dentry *dentry, *root;
2519 struct qstr this;
2520
2521 if (IS_ERR(shm_mnt))
2522 return (void *)shm_mnt;
2523
2524 if (size < 0 || size > SHMEM_MAX_BYTES)
2525 return ERR_PTR(-EINVAL);
2526
2527 if (shmem_acct_size(flags, size))
2528 return ERR_PTR(-ENOMEM);
2529
2530 error = -ENOMEM;
2531 this.name = name;
2532 this.len = strlen(name);
2533 this.hash = 0; /* will go */
2534 root = shm_mnt->mnt_root;
2535 dentry = d_alloc(root, &this);
2536 if (!dentry)
2537 goto put_memory;
2538
2539 error = -ENFILE;
2540 file = get_empty_filp();
2541 if (!file)
2542 goto put_dentry;
2543
2544 error = -ENOSPC;
2545 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
2546 if (!inode)
2547 goto close_file;
2548
2549 SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
2550 d_instantiate(dentry, inode);
2551 inode->i_size = size;
2552 inode->i_nlink = 0; /* It is unlinked */
Dave Hansence8d2cd2007-10-16 23:31:13 -07002553 init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
2554 &shmem_file_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002555 return file;
2556
2557close_file:
2558 put_filp(file);
2559put_dentry:
2560 dput(dentry);
2561put_memory:
2562 shmem_unacct_size(flags, size);
2563 return ERR_PTR(error);
2564}
2565
2566/*
2567 * shmem_zero_setup - setup a shared anonymous mapping
2568 *
2569 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2570 */
2571int shmem_zero_setup(struct vm_area_struct *vma)
2572{
2573 struct file *file;
2574 loff_t size = vma->vm_end - vma->vm_start;
2575
2576 file = shmem_file_setup("dev/zero", size, vma->vm_flags);
2577 if (IS_ERR(file))
2578 return PTR_ERR(file);
2579
2580 if (vma->vm_file)
2581 fput(vma->vm_file);
2582 vma->vm_file = file;
2583 vma->vm_ops = &shmem_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002584 return 0;
2585}