blob: 1c44af71fcf5044be40d2e22b19dd66726e3f8be [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 Dickins6922c0c2011-08-03 16:21:25 -07009 * Copyright (C) 2002-2011 Hugh Dickins.
10 * Copyright (C) 2011 Google Inc.
Hugh Dickins0edd73b2005-06-21 17:15:04 -070011 * Copyright (C) 2002-2005 VERITAS Software Corporation.
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 * Copyright (C) 2004 Andi Kleen, SuSE Labs
13 *
14 * Extended attribute support for tmpfs:
15 * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
16 * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
17 *
Matt Mackall853ac432009-01-06 14:40:20 -080018 * tiny-shmem:
19 * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
20 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070021 * This file is released under the GPL.
22 */
23
Matt Mackall853ac432009-01-06 14:40:20 -080024#include <linux/fs.h>
25#include <linux/init.h>
26#include <linux/vfs.h>
27#include <linux/mount.h>
Hugh Dickinscaefba12009-04-13 14:40:12 -070028#include <linux/pagemap.h>
Matt Mackall853ac432009-01-06 14:40:20 -080029#include <linux/file.h>
30#include <linux/mm.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040031#include <linux/export.h>
Matt Mackall853ac432009-01-06 14:40:20 -080032#include <linux/swap.h>
33
34static struct vfsmount *shm_mnt;
35
36#ifdef CONFIG_SHMEM
Linus Torvalds1da177e2005-04-16 15:20:36 -070037/*
38 * This virtual memory filesystem is heavily based on the ramfs. It
39 * extends ramfs by the ability to use swap and honor resource limits
40 * which makes it a completely usable filesystem.
41 */
42
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070043#include <linux/xattr.h>
Christoph Hellwiga5694252007-07-17 04:04:28 -070044#include <linux/exportfs.h>
Christoph Hellwig1c7c4742009-11-03 16:44:44 +010045#include <linux/posix_acl.h>
Andreas Gruenbacher39f02472006-09-29 02:01:35 -070046#include <linux/generic_acl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/mman.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070048#include <linux/string.h>
49#include <linux/slab.h>
50#include <linux/backing-dev.h>
51#include <linux/shmem_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052#include <linux/writeback.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#include <linux/blkdev.h>
Hugh Dickinsbda97ea2011-08-03 16:21:21 -070054#include <linux/pagevec.h>
Hugh Dickins41ffe5d2011-08-03 16:21:21 -070055#include <linux/percpu_counter.h>
Hugh Dickins83e4fa92012-05-29 15:06:40 -070056#include <linux/falloc.h>
Hugh Dickins708e3502011-07-25 17:12:32 -070057#include <linux/splice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058#include <linux/security.h>
59#include <linux/swapops.h>
60#include <linux/mempolicy.h>
61#include <linux/namei.h>
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +000062#include <linux/ctype.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070063#include <linux/migrate.h>
Christoph Lameterc1f60a52006-09-25 23:31:11 -070064#include <linux/highmem.h>
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -080065#include <linux/seq_file.h>
Mimi Zohar92562922008-10-07 14:00:12 -040066#include <linux/magic.h>
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -070067
Linus Torvalds1da177e2005-04-16 15:20:36 -070068#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070069#include <asm/pgtable.h>
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
Linus Torvalds1da177e2005-04-16 15:20:36 -070072#define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
73
Linus Torvalds1da177e2005-04-16 15:20:36 -070074/* Pretend that each entry is of this size in directory's i_size */
75#define BOGO_DIRENT_SIZE 20
76
Hugh Dickins69f07ec2011-08-03 16:21:26 -070077/* Symlink up to this size is kmalloc'ed instead of using a swappable page */
78#define SHORT_SYMLINK_LEN 128
79
Hugh Dickins1aac1402012-05-29 15:06:42 -070080/*
81 * shmem_fallocate and shmem_writepage communicate via inode->i_private
82 * (with i_mutex making sure that it has only one user at a time):
83 * we would prefer not to enlarge the shmem inode just for that.
84 */
85struct shmem_falloc {
86 pgoff_t start; /* start of range currently being fallocated */
87 pgoff_t next; /* the next page offset to be fallocated */
88 pgoff_t nr_falloced; /* how many new pages have been fallocated */
89 pgoff_t nr_unswapped; /* how often writepage refused to swap out */
90};
91
Hugh Dickins285b2c42011-08-03 16:21:20 -070092/* Flag allocation requirements to shmem_getpage */
Linus Torvalds1da177e2005-04-16 15:20:36 -070093enum sgp_type {
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 SGP_READ, /* don't exceed i_size, don't allocate page */
95 SGP_CACHE, /* don't exceed i_size, may allocate page */
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -080096 SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
Hugh Dickins1635f6a2012-05-29 15:06:42 -070097 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
98 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
Linus Torvalds1da177e2005-04-16 15:20:36 -070099};
100
Andrew Mortonb76db732008-02-08 04:21:49 -0800101#ifdef CONFIG_TMPFS
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800102static unsigned long shmem_default_max_blocks(void)
103{
104 return totalram_pages / 2;
105}
106
107static unsigned long shmem_default_max_inodes(void)
108{
109 return min(totalram_pages - totalhigh_pages, totalram_pages / 2);
110}
Andrew Mortonb76db732008-02-08 04:21:49 -0800111#endif
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800112
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700113static bool shmem_should_replace_page(struct page *page, gfp_t gfp);
114static int shmem_replace_page(struct page **pagep, gfp_t gfp,
115 struct shmem_inode_info *info, pgoff_t index);
Hugh Dickins68da9f02011-07-25 17:12:34 -0700116static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
117 struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type);
118
119static inline int shmem_getpage(struct inode *inode, pgoff_t index,
120 struct page **pagep, enum sgp_type sgp, int *fault_type)
121{
122 return shmem_getpage_gfp(inode, index, pagep, sgp,
123 mapping_gfp_mask(inode->i_mapping), fault_type);
124}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
127{
128 return sb->s_fs_info;
129}
130
131/*
132 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
133 * for shared memory and for shared anonymous (/dev/zero) mappings
134 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
135 * consistent with the pre-accounting of private mappings ...
136 */
137static inline int shmem_acct_size(unsigned long flags, loff_t size)
138{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000139 return (flags & VM_NORESERVE) ?
Al Viro191c5422012-02-13 03:58:52 +0000140 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141}
142
143static inline void shmem_unacct_size(unsigned long flags, loff_t size)
144{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000145 if (!(flags & VM_NORESERVE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 vm_unacct_memory(VM_ACCT(size));
147}
148
149/*
150 * ... whereas tmpfs objects are accounted incrementally as
151 * pages are allocated, in order to allow huge sparse files.
152 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
153 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
154 */
155static inline int shmem_acct_block(unsigned long flags)
156{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000157 return (flags & VM_NORESERVE) ?
Al Viro191c5422012-02-13 03:58:52 +0000158 security_vm_enough_memory_mm(current->mm, VM_ACCT(PAGE_CACHE_SIZE)) : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159}
160
161static inline void shmem_unacct_blocks(unsigned long flags, long pages)
162{
Hugh Dickins0b0a0802009-02-24 20:51:52 +0000163 if (flags & VM_NORESERVE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
165}
166
Hugh Dickins759b9772007-03-05 00:30:28 -0800167static const struct super_operations shmem_ops;
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700168static const struct address_space_operations shmem_aops;
Helge Deller15ad7cd2006-12-06 20:40:36 -0800169static const struct file_operations shmem_file_operations;
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800170static const struct inode_operations shmem_inode_operations;
171static const struct inode_operations shmem_dir_inode_operations;
172static const struct inode_operations shmem_special_inode_operations;
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400173static const struct vm_operations_struct shmem_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
Ravikiran G Thirumalai6c231b72005-09-06 15:17:45 -0700175static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 .ra_pages = 0, /* No readahead */
Rik van Riel4f98a2f2008-10-18 20:26:32 -0700177 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178};
179
180static LIST_HEAD(shmem_swaplist);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800181static DEFINE_MUTEX(shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
Pavel Emelyanov5b04c682008-02-04 22:28:47 -0800183static int shmem_reserve_inode(struct super_block *sb)
184{
185 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
186 if (sbinfo->max_inodes) {
187 spin_lock(&sbinfo->stat_lock);
188 if (!sbinfo->free_inodes) {
189 spin_unlock(&sbinfo->stat_lock);
190 return -ENOSPC;
191 }
192 sbinfo->free_inodes--;
193 spin_unlock(&sbinfo->stat_lock);
194 }
195 return 0;
196}
197
198static void shmem_free_inode(struct super_block *sb)
199{
200 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
201 if (sbinfo->max_inodes) {
202 spin_lock(&sbinfo->stat_lock);
203 sbinfo->free_inodes++;
204 spin_unlock(&sbinfo->stat_lock);
205 }
206}
207
Randy Dunlap46711812008-03-19 17:00:41 -0700208/**
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700209 * shmem_recalc_inode - recalculate the block usage of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 * @inode: inode to recalc
211 *
212 * We have to calculate the free blocks since the mm can drop
213 * undirtied hole pages behind our back.
214 *
215 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
216 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
217 *
218 * It has to be called with the spinlock held.
219 */
220static void shmem_recalc_inode(struct inode *inode)
221{
222 struct shmem_inode_info *info = SHMEM_I(inode);
223 long freed;
224
225 freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
226 if (freed > 0) {
Hugh Dickins54af60422011-08-03 16:21:24 -0700227 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
228 if (sbinfo->max_blocks)
229 percpu_counter_add(&sbinfo->used_blocks, -freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 info->alloced -= freed;
Hugh Dickins54af60422011-08-03 16:21:24 -0700231 inode->i_blocks -= freed * BLOCKS_PER_PAGE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 shmem_unacct_blocks(info->flags, freed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 }
234}
235
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700236/*
237 * Replace item expected in radix tree by a new item, while holding tree lock.
238 */
239static int shmem_radix_tree_replace(struct address_space *mapping,
240 pgoff_t index, void *expected, void *replacement)
241{
242 void **pslot;
243 void *item = NULL;
244
245 VM_BUG_ON(!expected);
246 pslot = radix_tree_lookup_slot(&mapping->page_tree, index);
247 if (pslot)
248 item = radix_tree_deref_slot_protected(pslot,
249 &mapping->tree_lock);
250 if (item != expected)
251 return -ENOENT;
252 if (replacement)
253 radix_tree_replace_slot(pslot, replacement);
254 else
255 radix_tree_delete(&mapping->page_tree, index);
256 return 0;
257}
258
259/*
Hugh Dickinsd1899222012-07-11 14:02:47 -0700260 * Sometimes, before we decide whether to proceed or to fail, we must check
261 * that an entry was not already brought back from swap by a racing thread.
262 *
263 * Checking page is not enough: by the time a SwapCache page is locked, it
264 * might be reused, and again be SwapCache, using the same swap as before.
265 */
266static bool shmem_confirm_swap(struct address_space *mapping,
267 pgoff_t index, swp_entry_t swap)
268{
269 void *item;
270
271 rcu_read_lock();
272 item = radix_tree_lookup(&mapping->page_tree, index);
273 rcu_read_unlock();
274 return item == swp_to_radix_entry(swap);
275}
276
277/*
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700278 * Like add_to_page_cache_locked, but error if expected item has gone.
279 */
280static int shmem_add_to_page_cache(struct page *page,
281 struct address_space *mapping,
282 pgoff_t index, gfp_t gfp, void *expected)
283{
Hugh Dickinsb065b432012-07-11 14:02:48 -0700284 int error;
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700285
286 VM_BUG_ON(!PageLocked(page));
287 VM_BUG_ON(!PageSwapBacked(page));
288
Hugh Dickinsb065b432012-07-11 14:02:48 -0700289 page_cache_get(page);
290 page->mapping = mapping;
291 page->index = index;
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700292
Hugh Dickinsb065b432012-07-11 14:02:48 -0700293 spin_lock_irq(&mapping->tree_lock);
294 if (!expected)
295 error = radix_tree_insert(&mapping->page_tree, index, page);
296 else
297 error = shmem_radix_tree_replace(mapping, index, expected,
298 page);
299 if (!error) {
300 mapping->nrpages++;
301 __inc_zone_page_state(page, NR_FILE_PAGES);
302 __inc_zone_page_state(page, NR_SHMEM);
303 spin_unlock_irq(&mapping->tree_lock);
304 } else {
305 page->mapping = NULL;
306 spin_unlock_irq(&mapping->tree_lock);
307 page_cache_release(page);
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700308 }
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700309 return error;
310}
311
312/*
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700313 * Like delete_from_page_cache, but substitutes swap for page.
314 */
315static void shmem_delete_from_page_cache(struct page *page, void *radswap)
316{
317 struct address_space *mapping = page->mapping;
318 int error;
319
320 spin_lock_irq(&mapping->tree_lock);
321 error = shmem_radix_tree_replace(mapping, page->index, page, radswap);
322 page->mapping = NULL;
323 mapping->nrpages--;
324 __dec_zone_page_state(page, NR_FILE_PAGES);
325 __dec_zone_page_state(page, NR_SHMEM);
326 spin_unlock_irq(&mapping->tree_lock);
327 page_cache_release(page);
328 BUG_ON(error);
329}
330
331/*
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700332 * Like find_get_pages, but collecting swap entries as well as pages.
333 */
334static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping,
335 pgoff_t start, unsigned int nr_pages,
336 struct page **pages, pgoff_t *indices)
337{
Johannes Weiner860f2752013-02-22 16:35:17 -0800338 void **slot;
339 unsigned int ret = 0;
340 struct radix_tree_iter iter;
341
342 if (!nr_pages)
343 return 0;
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700344
345 rcu_read_lock();
346restart:
Johannes Weiner860f2752013-02-22 16:35:17 -0800347 radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700348 struct page *page;
349repeat:
Johannes Weiner860f2752013-02-22 16:35:17 -0800350 page = radix_tree_deref_slot(slot);
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700351 if (unlikely(!page))
352 continue;
353 if (radix_tree_exception(page)) {
Hugh Dickins8079b1c2011-08-03 16:21:28 -0700354 if (radix_tree_deref_retry(page))
355 goto restart;
356 /*
357 * Otherwise, we must be storing a swap entry
358 * here as an exceptional entry: so return it
359 * without attempting to raise page count.
360 */
361 goto export;
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700362 }
363 if (!page_cache_get_speculative(page))
364 goto repeat;
365
366 /* Has the page moved? */
Johannes Weiner860f2752013-02-22 16:35:17 -0800367 if (unlikely(page != *slot)) {
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700368 page_cache_release(page);
369 goto repeat;
370 }
371export:
Johannes Weiner860f2752013-02-22 16:35:17 -0800372 indices[ret] = iter.index;
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700373 pages[ret] = page;
Johannes Weiner860f2752013-02-22 16:35:17 -0800374 if (++ret == nr_pages)
375 break;
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700376 }
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700377 rcu_read_unlock();
378 return ret;
379}
380
381/*
382 * Remove swap entry from radix tree, free the swap and its page cache.
383 */
384static int shmem_free_swap(struct address_space *mapping,
385 pgoff_t index, void *radswap)
386{
387 int error;
388
389 spin_lock_irq(&mapping->tree_lock);
390 error = shmem_radix_tree_replace(mapping, index, radswap, NULL);
391 spin_unlock_irq(&mapping->tree_lock);
392 if (!error)
393 free_swap_and_cache(radix_to_swp_entry(radswap));
394 return error;
395}
396
397/*
398 * Pagevec may contain swap entries, so shuffle up pages before releasing.
399 */
Hugh Dickins24513262012-01-20 14:34:21 -0800400static void shmem_deswap_pagevec(struct pagevec *pvec)
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700401{
402 int i, j;
403
404 for (i = 0, j = 0; i < pagevec_count(pvec); i++) {
405 struct page *page = pvec->pages[i];
406 if (!radix_tree_exceptional_entry(page))
407 pvec->pages[j++] = page;
408 }
409 pvec->nr = j;
Hugh Dickins24513262012-01-20 14:34:21 -0800410}
411
412/*
413 * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
414 */
415void shmem_unlock_mapping(struct address_space *mapping)
416{
417 struct pagevec pvec;
418 pgoff_t indices[PAGEVEC_SIZE];
419 pgoff_t index = 0;
420
421 pagevec_init(&pvec, 0);
422 /*
423 * Minor point, but we might as well stop if someone else SHM_LOCKs it.
424 */
425 while (!mapping_unevictable(mapping)) {
426 /*
427 * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it
428 * has finished, if it hits a row of PAGEVEC_SIZE swap entries.
429 */
430 pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
431 PAGEVEC_SIZE, pvec.pages, indices);
432 if (!pvec.nr)
433 break;
434 index = indices[pvec.nr - 1] + 1;
435 shmem_deswap_pagevec(&pvec);
436 check_move_unevictable_pages(pvec.pages, pvec.nr);
437 pagevec_release(&pvec);
438 cond_resched();
439 }
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700440}
441
442/*
443 * Remove range of pages and swap entries from radix tree, and free them.
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700444 * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700445 */
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700446static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
447 bool unfalloc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448{
Hugh Dickins285b2c42011-08-03 16:21:20 -0700449 struct address_space *mapping = inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 struct shmem_inode_info *info = SHMEM_I(inode);
Hugh Dickins285b2c42011-08-03 16:21:20 -0700451 pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700452 pgoff_t end = (lend + 1) >> PAGE_CACHE_SHIFT;
453 unsigned int partial_start = lstart & (PAGE_CACHE_SIZE - 1);
454 unsigned int partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1);
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700455 struct pagevec pvec;
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700456 pgoff_t indices[PAGEVEC_SIZE];
457 long nr_swaps_freed = 0;
Hugh Dickins285b2c42011-08-03 16:21:20 -0700458 pgoff_t index;
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700459 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700461 if (lend == -1)
462 end = -1; /* unsigned, so actually very big */
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700463
464 pagevec_init(&pvec, 0);
465 index = start;
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700466 while (index < end) {
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700467 pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700468 min(end - index, (pgoff_t)PAGEVEC_SIZE),
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700469 pvec.pages, indices);
470 if (!pvec.nr)
471 break;
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700472 mem_cgroup_uncharge_start();
473 for (i = 0; i < pagevec_count(&pvec); i++) {
474 struct page *page = pvec.pages[i];
475
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700476 index = indices[i];
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700477 if (index >= end)
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700478 break;
479
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700480 if (radix_tree_exceptional_entry(page)) {
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700481 if (unfalloc)
482 continue;
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700483 nr_swaps_freed += !shmem_free_swap(mapping,
484 index, page);
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700485 continue;
486 }
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700487
488 if (!trylock_page(page))
489 continue;
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700490 if (!unfalloc || !PageUptodate(page)) {
491 if (page->mapping == mapping) {
492 VM_BUG_ON(PageWriteback(page));
493 truncate_inode_page(mapping, page);
494 }
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700495 }
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700496 unlock_page(page);
497 }
Hugh Dickins24513262012-01-20 14:34:21 -0800498 shmem_deswap_pagevec(&pvec);
499 pagevec_release(&pvec);
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700500 mem_cgroup_uncharge_end();
501 cond_resched();
502 index++;
503 }
504
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700505 if (partial_start) {
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700506 struct page *page = NULL;
507 shmem_getpage(inode, start - 1, &page, SGP_READ, NULL);
508 if (page) {
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700509 unsigned int top = PAGE_CACHE_SIZE;
510 if (start > end) {
511 top = partial_end;
512 partial_end = 0;
513 }
514 zero_user_segment(page, partial_start, top);
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700515 set_page_dirty(page);
516 unlock_page(page);
517 page_cache_release(page);
518 }
519 }
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700520 if (partial_end) {
521 struct page *page = NULL;
522 shmem_getpage(inode, end, &page, SGP_READ, NULL);
523 if (page) {
524 zero_user_segment(page, 0, partial_end);
525 set_page_dirty(page);
526 unlock_page(page);
527 page_cache_release(page);
528 }
529 }
530 if (start >= end)
531 return;
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700532
533 index = start;
534 for ( ; ; ) {
535 cond_resched();
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700536 pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700537 min(end - index, (pgoff_t)PAGEVEC_SIZE),
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700538 pvec.pages, indices);
539 if (!pvec.nr) {
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700540 if (index == start || unfalloc)
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700541 break;
542 index = start;
543 continue;
544 }
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700545 if ((index == start || unfalloc) && indices[0] >= end) {
Hugh Dickins24513262012-01-20 14:34:21 -0800546 shmem_deswap_pagevec(&pvec);
547 pagevec_release(&pvec);
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700548 break;
549 }
550 mem_cgroup_uncharge_start();
551 for (i = 0; i < pagevec_count(&pvec); i++) {
552 struct page *page = pvec.pages[i];
553
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700554 index = indices[i];
Hugh Dickins83e4fa92012-05-29 15:06:40 -0700555 if (index >= end)
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700556 break;
557
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700558 if (radix_tree_exceptional_entry(page)) {
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700559 if (unfalloc)
560 continue;
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700561 nr_swaps_freed += !shmem_free_swap(mapping,
562 index, page);
563 continue;
564 }
565
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700566 lock_page(page);
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700567 if (!unfalloc || !PageUptodate(page)) {
568 if (page->mapping == mapping) {
569 VM_BUG_ON(PageWriteback(page));
570 truncate_inode_page(mapping, page);
571 }
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700572 }
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700573 unlock_page(page);
574 }
Hugh Dickins24513262012-01-20 14:34:21 -0800575 shmem_deswap_pagevec(&pvec);
576 pagevec_release(&pvec);
Hugh Dickinsbda97ea2011-08-03 16:21:21 -0700577 mem_cgroup_uncharge_end();
578 index++;
579 }
Hugh Dickins94c1e622011-06-27 16:18:03 -0700580
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 spin_lock(&info->lock);
Hugh Dickins7a5d0fb2011-08-03 16:21:22 -0700582 info->swapped -= nr_swaps_freed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 shmem_recalc_inode(inode);
584 spin_unlock(&info->lock);
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700585}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700587void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
588{
589 shmem_undo_range(inode, lstart, lend, false);
Hugh Dickins285b2c42011-08-03 16:21:20 -0700590 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591}
Hugh Dickins94c1e622011-06-27 16:18:03 -0700592EXPORT_SYMBOL_GPL(shmem_truncate_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
Hugh Dickins94c1e622011-06-27 16:18:03 -0700594static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595{
596 struct inode *inode = dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 int error;
598
Christoph Hellwigdb78b872010-06-04 11:30:03 +0200599 error = inode_change_ok(inode, attr);
600 if (error)
601 return error;
602
Hugh Dickins94c1e622011-06-27 16:18:03 -0700603 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
604 loff_t oldsize = inode->i_size;
605 loff_t newsize = attr->ia_size;
npiggin@suse.de3889e6e2010-05-27 01:05:36 +1000606
Hugh Dickins94c1e622011-06-27 16:18:03 -0700607 if (newsize != oldsize) {
608 i_size_write(inode, newsize);
609 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
610 }
611 if (newsize < oldsize) {
612 loff_t holebegin = round_up(newsize, PAGE_SIZE);
613 unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);
614 shmem_truncate_range(inode, newsize, (loff_t)-1);
615 /* unmap again to remove racily COWed private pages */
616 unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);
617 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 }
619
Christoph Hellwigdb78b872010-06-04 11:30:03 +0200620 setattr_copy(inode, attr);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700621#ifdef CONFIG_TMPFS_POSIX_ACL
Christoph Hellwigdb78b872010-06-04 11:30:03 +0200622 if (attr->ia_valid & ATTR_MODE)
Christoph Hellwig1c7c4742009-11-03 16:44:44 +0100623 error = generic_acl_chmod(inode);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -0700624#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 return error;
626}
627
Al Viro1f895f72010-06-05 19:10:41 -0400628static void shmem_evict_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 struct shmem_inode_info *info = SHMEM_I(inode);
631
npiggin@suse.de3889e6e2010-05-27 01:05:36 +1000632 if (inode->i_mapping->a_ops == &shmem_aops) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 shmem_unacct_size(info->flags, inode->i_size);
634 inode->i_size = 0;
npiggin@suse.de3889e6e2010-05-27 01:05:36 +1000635 shmem_truncate_range(inode, 0, (loff_t)-1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 if (!list_empty(&info->swaplist)) {
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800637 mutex_lock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 list_del_init(&info->swaplist);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800639 mutex_unlock(&shmem_swaplist_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 }
Hugh Dickins69f07ec2011-08-03 16:21:26 -0700641 } else
642 kfree(info->symlink);
Eric Parisb09e0fa2011-05-24 17:12:39 -0700643
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400644 simple_xattrs_free(&info->xattrs);
Hugh Dickins0f3c42f2012-11-16 14:15:04 -0800645 WARN_ON(inode->i_blocks);
Pavel Emelyanov5b04c682008-02-04 22:28:47 -0800646 shmem_free_inode(inode->i_sb);
Jan Karadbd57682012-05-03 14:48:02 +0200647 clear_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648}
649
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700650/*
651 * If swap found in inode, free it and move page from swapcache to filecache.
652 */
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700653static int shmem_unuse_inode(struct shmem_inode_info *info,
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700654 swp_entry_t swap, struct page **pagep)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655{
Hugh Dickins285b2c42011-08-03 16:21:20 -0700656 struct address_space *mapping = info->vfs_inode.i_mapping;
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700657 void *radswap;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700658 pgoff_t index;
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700659 gfp_t gfp;
660 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700662 radswap = swp_to_radix_entry(swap);
Hugh Dickinse504f3f2011-08-03 16:21:27 -0700663 index = radix_tree_locate_item(&mapping->page_tree, radswap);
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700664 if (index == -1)
Hugh Dickins285b2c42011-08-03 16:21:20 -0700665 return 0;
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800666
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800667 /*
668 * Move _head_ to start search for next from here.
Al Viro1f895f72010-06-05 19:10:41 -0400669 * But be careful: shmem_evict_inode checks list_empty without taking
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800670 * mutex, and there's an instant in list_move_tail when info->swaplist
Hugh Dickins285b2c42011-08-03 16:21:20 -0700671 * would appear empty, if it were the only one on shmem_swaplist.
Hugh Dickins1b1b32f2008-02-04 22:28:55 -0800672 */
673 if (shmem_swaplist.next != &info->swaplist)
674 list_move_tail(&shmem_swaplist, &info->swaplist);
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800675
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700676 gfp = mapping_gfp_mask(mapping);
677 if (shmem_should_replace_page(*pagep, gfp)) {
678 mutex_unlock(&shmem_swaplist_mutex);
679 error = shmem_replace_page(pagep, gfp, info, index);
680 mutex_lock(&shmem_swaplist_mutex);
681 /*
682 * We needed to drop mutex to make that restrictive page
Hugh Dickins0142ef62012-06-07 14:21:09 -0700683 * allocation, but the inode might have been freed while we
684 * dropped it: although a racing shmem_evict_inode() cannot
685 * complete without emptying the radix_tree, our page lock
686 * on this swapcache page is not enough to prevent that -
687 * free_swap_and_cache() of our swap entry will only
688 * trylock_page(), removing swap from radix_tree whatever.
689 *
690 * We must not proceed to shmem_add_to_page_cache() if the
691 * inode has been freed, but of course we cannot rely on
692 * inode or mapping or info to check that. However, we can
693 * safely check if our swap entry is still in use (and here
694 * it can't have got reused for another page): if it's still
695 * in use, then the inode cannot have been freed yet, and we
696 * can safely proceed (if it's no longer in use, that tells
697 * nothing about the inode, but we don't need to unuse swap).
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700698 */
699 if (!page_swapcount(*pagep))
700 error = -ENOENT;
701 }
702
KAMEZAWA Hiroyukid13d1442009-01-07 18:07:56 -0800703 /*
Hugh Dickins778dd892011-05-11 15:13:37 -0700704 * We rely on shmem_swaplist_mutex, not only to protect the swaplist,
705 * but also to hold up shmem_evict_inode(): so inode cannot be freed
706 * beneath us (pagelock doesn't help until the page is in pagecache).
KAMEZAWA Hiroyukid13d1442009-01-07 18:07:56 -0800707 */
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700708 if (!error)
709 error = shmem_add_to_page_cache(*pagep, mapping, index,
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700710 GFP_NOWAIT, radswap);
Hugh Dickins48f170f2011-07-25 17:12:37 -0700711 if (error != -ENOMEM) {
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700712 /*
713 * Truncation and eviction use free_swap_and_cache(), which
714 * only does trylock page: if we raced, best clean up here.
715 */
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700716 delete_from_swap_cache(*pagep);
717 set_page_dirty(*pagep);
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700718 if (!error) {
719 spin_lock(&info->lock);
720 info->swapped--;
721 spin_unlock(&info->lock);
722 swap_free(swap);
723 }
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800724 error = 1; /* not an error, but entry was found */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 }
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800726 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727}
728
729/*
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700730 * Search through swapped inodes to find and replace swap by page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 */
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700732int shmem_unuse(swp_entry_t swap, struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733{
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700734 struct list_head *this, *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 struct shmem_inode_info *info;
736 int found = 0;
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700737 int error = 0;
738
739 /*
740 * There's a faint possibility that swap page was replaced before
Hugh Dickins0142ef62012-06-07 14:21:09 -0700741 * caller locked it: caller will come back later with the right page.
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700742 */
Hugh Dickins0142ef62012-06-07 14:21:09 -0700743 if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val))
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700744 goto out;
Hugh Dickins778dd892011-05-11 15:13:37 -0700745
746 /*
747 * Charge page using GFP_KERNEL while we can wait, before taking
748 * the shmem_swaplist_mutex which might hold up shmem_writepage().
749 * Charged back to the user (not to caller) when swap account is used.
Hugh Dickins778dd892011-05-11 15:13:37 -0700750 */
751 error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
752 if (error)
753 goto out;
Hugh Dickins46f65ec2011-08-03 16:21:23 -0700754 /* No radix_tree_preload: swap entry keeps a place for page in tree */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800756 mutex_lock(&shmem_swaplist_mutex);
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700757 list_for_each_safe(this, next, &shmem_swaplist) {
758 info = list_entry(this, struct shmem_inode_info, swaplist);
Hugh Dickins285b2c42011-08-03 16:21:20 -0700759 if (info->swapped)
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700760 found = shmem_unuse_inode(info, swap, &page);
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700761 else
762 list_del_init(&info->swaplist);
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800763 cond_resched();
Hugh Dickins2e0e26c2008-02-04 22:28:53 -0800764 if (found)
Hugh Dickins778dd892011-05-11 15:13:37 -0700765 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 }
Hugh Dickinscb5f7b92008-02-04 22:28:52 -0800767 mutex_unlock(&shmem_swaplist_mutex);
Hugh Dickins778dd892011-05-11 15:13:37 -0700768
Hugh Dickins778dd892011-05-11 15:13:37 -0700769 if (found < 0)
770 error = found;
771out:
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800772 unlock_page(page);
773 page_cache_release(page);
Hugh Dickins778dd892011-05-11 15:13:37 -0700774 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775}
776
777/*
778 * Move the page from the page cache to the swap cache.
779 */
780static int shmem_writepage(struct page *page, struct writeback_control *wbc)
781{
782 struct shmem_inode_info *info;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 struct address_space *mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 struct inode *inode;
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700785 swp_entry_t swap;
786 pgoff_t index;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787
788 BUG_ON(!PageLocked(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 mapping = page->mapping;
790 index = page->index;
791 inode = mapping->host;
792 info = SHMEM_I(inode);
793 if (info->flags & VM_LOCKED)
794 goto redirty;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800795 if (!total_swap_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 goto redirty;
797
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800798 /*
799 * shmem_backing_dev_info's capabilities prevent regular writeback or
800 * sync from ever calling shmem_writepage; but a stacking filesystem
Hugh Dickins48f170f2011-07-25 17:12:37 -0700801 * might use ->writepage of its underlying filesystem, in which case
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800802 * tmpfs should write out to swap only in response to memory pressure,
Hugh Dickins48f170f2011-07-25 17:12:37 -0700803 * and not for the writeback threads or sync.
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800804 */
Hugh Dickins48f170f2011-07-25 17:12:37 -0700805 if (!wbc->for_reclaim) {
806 WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
807 goto redirty;
808 }
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700809
810 /*
811 * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC
812 * value into swapfile.c, the only way we can correctly account for a
813 * fallocated page arriving here is now to initialize it and write it.
Hugh Dickins1aac1402012-05-29 15:06:42 -0700814 *
815 * That's okay for a page already fallocated earlier, but if we have
816 * not yet completed the fallocation, then (a) we want to keep track
817 * of this page in case we have to undo it, and (b) it may not be a
818 * good idea to continue anyway, once we're pushing into swap. So
819 * reactivate the page, and let shmem_fallocate() quit when too many.
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700820 */
821 if (!PageUptodate(page)) {
Hugh Dickins1aac1402012-05-29 15:06:42 -0700822 if (inode->i_private) {
823 struct shmem_falloc *shmem_falloc;
824 spin_lock(&inode->i_lock);
825 shmem_falloc = inode->i_private;
826 if (shmem_falloc &&
827 index >= shmem_falloc->start &&
828 index < shmem_falloc->next)
829 shmem_falloc->nr_unswapped++;
830 else
831 shmem_falloc = NULL;
832 spin_unlock(&inode->i_lock);
833 if (shmem_falloc)
834 goto redirty;
835 }
Hugh Dickins1635f6a2012-05-29 15:06:42 -0700836 clear_highpage(page);
837 flush_dcache_page(page);
838 SetPageUptodate(page);
839 }
840
Hugh Dickins48f170f2011-07-25 17:12:37 -0700841 swap = get_swap_page();
842 if (!swap.val)
843 goto redirty;
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800844
Hugh Dickinsb1dea802011-05-11 15:13:36 -0700845 /*
846 * Add inode to shmem_unuse()'s list of swapped-out inodes,
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700847 * if it's not already there. Do it now before the page is
848 * moved to swap cache, when its pagelock no longer protects
Hugh Dickinsb1dea802011-05-11 15:13:36 -0700849 * the inode from eviction. But don't unlock the mutex until
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700850 * we've incremented swapped, because shmem_unuse_inode() will
851 * prune a !swapped inode from the swaplist under this mutex.
Hugh Dickinsb1dea802011-05-11 15:13:36 -0700852 */
Hugh Dickins48f170f2011-07-25 17:12:37 -0700853 mutex_lock(&shmem_swaplist_mutex);
854 if (list_empty(&info->swaplist))
855 list_add_tail(&info->swaplist, &shmem_swaplist);
Hugh Dickinsb1dea802011-05-11 15:13:36 -0700856
Hugh Dickins48f170f2011-07-25 17:12:37 -0700857 if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
Hugh Dickinsaaa46862009-12-14 17:58:47 -0800858 swap_shmem_alloc(swap);
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700859 shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
860
861 spin_lock(&info->lock);
862 info->swapped++;
863 shmem_recalc_inode(inode);
Hugh Dickins826267c2011-05-28 13:14:09 -0700864 spin_unlock(&info->lock);
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700865
866 mutex_unlock(&shmem_swaplist_mutex);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800867 BUG_ON(page_mapped(page));
Hugh Dickins9fab5612009-03-31 15:23:33 -0700868 swap_writepage(page, wbc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 return 0;
870 }
871
Hugh Dickins6922c0c2011-08-03 16:21:25 -0700872 mutex_unlock(&shmem_swaplist_mutex);
KAMEZAWA Hiroyukicb4b86b2009-06-16 15:32:52 -0700873 swapcache_free(swap, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874redirty:
875 set_page_dirty(page);
Hugh Dickinsd9fe5262008-02-04 22:28:51 -0800876 if (wbc->for_reclaim)
877 return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */
878 unlock_page(page);
879 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880}
881
882#ifdef CONFIG_NUMA
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800883#ifdef CONFIG_TMPFS
Lee Schermerhorn71fe8042008-04-28 02:13:26 -0700884static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800885{
Lee Schermerhorn095f1fc2008-04-28 02:13:23 -0700886 char buffer[64];
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800887
Lee Schermerhorn71fe8042008-04-28 02:13:26 -0700888 if (!mpol || mpol->mode == MPOL_DEFAULT)
Lee Schermerhorn095f1fc2008-04-28 02:13:23 -0700889 return; /* show nothing */
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800890
Hugh Dickinsa7a88b22013-01-02 02:04:23 -0800891 mpol_to_str(buffer, sizeof(buffer), mpol);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800892
Lee Schermerhorn095f1fc2008-04-28 02:13:23 -0700893 seq_printf(seq, ",mpol=%s", buffer);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800894}
Lee Schermerhorn71fe8042008-04-28 02:13:26 -0700895
896static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
897{
898 struct mempolicy *mpol = NULL;
899 if (sbinfo->mpol) {
900 spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */
901 mpol = sbinfo->mpol;
902 mpol_get(mpol);
903 spin_unlock(&sbinfo->stat_lock);
904 }
905 return mpol;
906}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800907#endif /* CONFIG_TMPFS */
908
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700909static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
910 struct shmem_inode_info *info, pgoff_t index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 struct vm_area_struct pvma;
Mel Gorman18a2f372012-12-05 14:01:41 -0800913 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -0800915 /* Create a pseudo vma that just contains the policy */
916 pvma.vm_start = 0;
Nathan Zimmer09c231c2012-07-31 16:46:17 -0700917 /* Bias interleave by inode number to distribute better across nodes */
918 pvma.vm_pgoff = index + info->vfs_inode.i_ino;
Hugh Dickinsc4cc6d02008-02-04 22:28:40 -0800919 pvma.vm_ops = NULL;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700920 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700921
Mel Gorman18a2f372012-12-05 14:01:41 -0800922 page = swapin_readahead(swap, gfp, &pvma, 0);
923
924 /* Drop reference taken by mpol_shared_policy_lookup() */
925 mpol_cond_put(pvma.vm_policy);
926
927 return page;
928}
929
930static struct page *shmem_alloc_page(gfp_t gfp,
931 struct shmem_inode_info *info, pgoff_t index)
932{
933 struct vm_area_struct pvma;
934 struct page *page;
935
936 /* Create a pseudo vma that just contains the policy */
937 pvma.vm_start = 0;
938 /* Bias interleave by inode number to distribute better across nodes */
939 pvma.vm_pgoff = index + info->vfs_inode.i_ino;
940 pvma.vm_ops = NULL;
941 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
942
943 page = alloc_page_vma(gfp, &pvma, 0);
944
945 /* Drop reference taken by mpol_shared_policy_lookup() */
946 mpol_cond_put(pvma.vm_policy);
947
948 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800950#else /* !CONFIG_NUMA */
951#ifdef CONFIG_TMPFS
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700952static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800953{
954}
955#endif /* CONFIG_TMPFS */
956
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700957static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
958 struct shmem_inode_info *info, pgoff_t index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959{
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700960 return swapin_readahead(swap, gfp, NULL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961}
962
Hugh Dickins02098fe2008-02-04 22:28:42 -0800963static inline struct page *shmem_alloc_page(gfp_t gfp,
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700964 struct shmem_inode_info *info, pgoff_t index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965{
Hugh Dickinse84e2e12007-11-28 18:55:10 +0000966 return alloc_page(gfp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -0800968#endif /* CONFIG_NUMA */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969
Lee Schermerhorn71fe8042008-04-28 02:13:26 -0700970#if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
971static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
972{
973 return NULL;
974}
975#endif
976
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977/*
Hugh Dickinsbde05d12012-05-29 15:06:38 -0700978 * When a page is moved from swapcache to shmem filecache (either by the
979 * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
980 * shmem_unuse_inode()), it may have been read in earlier from swap, in
981 * ignorance of the mapping it belongs to. If that mapping has special
982 * constraints (like the gma500 GEM driver, which requires RAM below 4GB),
983 * we may need to copy to a suitable page before moving to filecache.
984 *
985 * In a future release, this may well be extended to respect cpuset and
986 * NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
987 * but for now it is a simple matter of zone.
988 */
989static bool shmem_should_replace_page(struct page *page, gfp_t gfp)
990{
991 return page_zonenum(page) > gfp_zone(gfp);
992}
993
994static int shmem_replace_page(struct page **pagep, gfp_t gfp,
995 struct shmem_inode_info *info, pgoff_t index)
996{
997 struct page *oldpage, *newpage;
998 struct address_space *swap_mapping;
999 pgoff_t swap_index;
1000 int error;
1001
1002 oldpage = *pagep;
1003 swap_index = page_private(oldpage);
1004 swap_mapping = page_mapping(oldpage);
1005
1006 /*
1007 * We have arrived here because our zones are constrained, so don't
1008 * limit chance of success by further cpuset and node constraints.
1009 */
1010 gfp &= ~GFP_CONSTRAINT_MASK;
1011 newpage = shmem_alloc_page(gfp, info, index);
1012 if (!newpage)
1013 return -ENOMEM;
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001014
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001015 page_cache_get(newpage);
1016 copy_highpage(newpage, oldpage);
Hugh Dickins0142ef62012-06-07 14:21:09 -07001017 flush_dcache_page(newpage);
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001018
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001019 __set_page_locked(newpage);
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001020 SetPageUptodate(newpage);
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001021 SetPageSwapBacked(newpage);
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001022 set_page_private(newpage, swap_index);
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001023 SetPageSwapCache(newpage);
1024
1025 /*
1026 * Our caller will very soon move newpage out of swapcache, but it's
1027 * a nice clean interface for us to replace oldpage by newpage there.
1028 */
1029 spin_lock_irq(&swap_mapping->tree_lock);
1030 error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage,
1031 newpage);
Hugh Dickins0142ef62012-06-07 14:21:09 -07001032 if (!error) {
1033 __inc_zone_page_state(newpage, NR_FILE_PAGES);
1034 __dec_zone_page_state(oldpage, NR_FILE_PAGES);
1035 }
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001036 spin_unlock_irq(&swap_mapping->tree_lock);
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001037
Hugh Dickins0142ef62012-06-07 14:21:09 -07001038 if (unlikely(error)) {
1039 /*
1040 * Is this possible? I think not, now that our callers check
1041 * both PageSwapCache and page_private after getting page lock;
1042 * but be defensive. Reverse old to newpage for clear and free.
1043 */
1044 oldpage = newpage;
1045 } else {
1046 mem_cgroup_replace_page_cache(oldpage, newpage);
1047 lru_cache_add_anon(newpage);
1048 *pagep = newpage;
1049 }
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001050
1051 ClearPageSwapCache(oldpage);
1052 set_page_private(oldpage, 0);
1053
1054 unlock_page(oldpage);
1055 page_cache_release(oldpage);
1056 page_cache_release(oldpage);
Hugh Dickins0142ef62012-06-07 14:21:09 -07001057 return error;
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001058}
1059
1060/*
Hugh Dickins68da9f02011-07-25 17:12:34 -07001061 * shmem_getpage_gfp - find page in cache, or get from swap, or allocate
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062 *
1063 * If we allocate a new one we do not mark it dirty. That's up to the
1064 * vm. If we swap it in we mark it dirty since we also free the swap
1065 * entry since a page cannot live in both the swap and page cache
1066 */
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001067static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
Hugh Dickins68da9f02011-07-25 17:12:34 -07001068 struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069{
1070 struct address_space *mapping = inode->i_mapping;
Hugh Dickins54af60422011-08-03 16:21:24 -07001071 struct shmem_inode_info *info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 struct shmem_sb_info *sbinfo;
Hugh Dickins27ab7002011-07-25 17:12:36 -07001073 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 swp_entry_t swap;
1075 int error;
Hugh Dickins54af60422011-08-03 16:21:24 -07001076 int once = 0;
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001077 int alloced = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001079 if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 return -EFBIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081repeat:
Hugh Dickins54af60422011-08-03 16:21:24 -07001082 swap.val = 0;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001083 page = find_lock_page(mapping, index);
Hugh Dickins54af60422011-08-03 16:21:24 -07001084 if (radix_tree_exceptional_entry(page)) {
1085 swap = radix_to_swp_entry(page);
1086 page = NULL;
1087 }
1088
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001089 if (sgp != SGP_WRITE && sgp != SGP_FALLOC &&
Hugh Dickins54af60422011-08-03 16:21:24 -07001090 ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
1091 error = -EINVAL;
1092 goto failed;
1093 }
1094
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001095 /* fallocated page? */
1096 if (page && !PageUptodate(page)) {
1097 if (sgp != SGP_READ)
1098 goto clear;
1099 unlock_page(page);
1100 page_cache_release(page);
1101 page = NULL;
1102 }
Hugh Dickins54af60422011-08-03 16:21:24 -07001103 if (page || (sgp == SGP_READ && !swap.val)) {
Hugh Dickins54af60422011-08-03 16:21:24 -07001104 *pagep = page;
1105 return 0;
Hugh Dickins27ab7002011-07-25 17:12:36 -07001106 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107
1108 /*
Hugh Dickins54af60422011-08-03 16:21:24 -07001109 * Fast cache lookup did not find it:
1110 * bring it back from swap or allocate.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111 */
Hugh Dickins54af60422011-08-03 16:21:24 -07001112 info = SHMEM_I(inode);
1113 sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins27ab7002011-07-25 17:12:36 -07001114
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115 if (swap.val) {
1116 /* Look it up and read it in.. */
Hugh Dickins27ab7002011-07-25 17:12:36 -07001117 page = lookup_swap_cache(swap);
1118 if (!page) {
Ying Han456f9982011-05-26 16:25:38 -07001119 /* here we actually do the io */
Hugh Dickins68da9f02011-07-25 17:12:34 -07001120 if (fault_type)
1121 *fault_type |= VM_FAULT_MAJOR;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001122 page = shmem_swapin(swap, gfp, info, index);
Hugh Dickins27ab7002011-07-25 17:12:36 -07001123 if (!page) {
Hugh Dickins54af60422011-08-03 16:21:24 -07001124 error = -ENOMEM;
1125 goto failed;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 }
1128
1129 /* We have to do this with page locked to prevent races */
Hugh Dickins54af60422011-08-03 16:21:24 -07001130 lock_page(page);
Hugh Dickins0142ef62012-06-07 14:21:09 -07001131 if (!PageSwapCache(page) || page_private(page) != swap.val ||
Hugh Dickinsd1899222012-07-11 14:02:47 -07001132 !shmem_confirm_swap(mapping, index, swap)) {
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001133 error = -EEXIST; /* try again */
Hugh Dickinsd1899222012-07-11 14:02:47 -07001134 goto unlock;
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001135 }
Hugh Dickins27ab7002011-07-25 17:12:36 -07001136 if (!PageUptodate(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 error = -EIO;
Hugh Dickins54af60422011-08-03 16:21:24 -07001138 goto failed;
1139 }
1140 wait_on_page_writeback(page);
1141
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001142 if (shmem_should_replace_page(page, gfp)) {
1143 error = shmem_replace_page(&page, gfp, info, index);
1144 if (error)
1145 goto failed;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 }
1147
Hugh Dickinsaa3b1892011-08-03 16:21:24 -07001148 error = mem_cgroup_cache_charge(page, current->mm,
1149 gfp & GFP_RECLAIM_MASK);
Hugh Dickinsd1899222012-07-11 14:02:47 -07001150 if (!error) {
Hugh Dickinsaa3b1892011-08-03 16:21:24 -07001151 error = shmem_add_to_page_cache(page, mapping, index,
1152 gfp, swp_to_radix_entry(swap));
Hugh Dickins215c02b2012-11-16 14:15:03 -08001153 /*
1154 * We already confirmed swap under page lock, and make
1155 * no memory allocation here, so usually no possibility
1156 * of error; but free_swap_and_cache() only trylocks a
1157 * page, so it is just possible that the entry has been
1158 * truncated or holepunched since swap was confirmed.
1159 * shmem_undo_range() will have done some of the
1160 * unaccounting, now delete_from_swap_cache() will do
1161 * the rest (including mem_cgroup_uncharge_swapcache).
1162 * Reset swap.val? No, leave it so "failed" goes back to
1163 * "repeat": reading a hole and writing should succeed.
1164 */
1165 if (error)
1166 delete_from_swap_cache(page);
Hugh Dickinsd1899222012-07-11 14:02:47 -07001167 }
Hugh Dickins54af60422011-08-03 16:21:24 -07001168 if (error)
1169 goto failed;
1170
1171 spin_lock(&info->lock);
1172 info->swapped--;
1173 shmem_recalc_inode(inode);
1174 spin_unlock(&info->lock);
Hugh Dickins27ab7002011-07-25 17:12:36 -07001175
Hugh Dickins27ab7002011-07-25 17:12:36 -07001176 delete_from_swap_cache(page);
Hugh Dickins27ab7002011-07-25 17:12:36 -07001177 set_page_dirty(page);
1178 swap_free(swap);
1179
Hugh Dickins54af60422011-08-03 16:21:24 -07001180 } else {
1181 if (shmem_acct_block(info->flags)) {
1182 error = -ENOSPC;
1183 goto failed;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001185 if (sbinfo->max_blocks) {
Hugh Dickinsfc5da222011-04-14 15:22:07 -07001186 if (percpu_counter_compare(&sbinfo->used_blocks,
Hugh Dickins54af60422011-08-03 16:21:24 -07001187 sbinfo->max_blocks) >= 0) {
1188 error = -ENOSPC;
1189 goto unacct;
1190 }
Tim Chen7e496292010-08-09 17:19:05 -07001191 percpu_counter_inc(&sbinfo->used_blocks);
Hugh Dickins59a16ea2011-05-11 15:13:38 -07001192 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193
Hugh Dickins54af60422011-08-03 16:21:24 -07001194 page = shmem_alloc_page(gfp, info, index);
1195 if (!page) {
1196 error = -ENOMEM;
1197 goto decused;
1198 }
1199
1200 SetPageSwapBacked(page);
1201 __set_page_locked(page);
Hugh Dickinsaa3b1892011-08-03 16:21:24 -07001202 error = mem_cgroup_cache_charge(page, current->mm,
1203 gfp & GFP_RECLAIM_MASK);
Hugh Dickins54af60422011-08-03 16:21:24 -07001204 if (error)
1205 goto decused;
Hugh Dickinsb065b432012-07-11 14:02:48 -07001206 error = radix_tree_preload(gfp & GFP_RECLAIM_MASK);
1207 if (!error) {
1208 error = shmem_add_to_page_cache(page, mapping, index,
1209 gfp, NULL);
1210 radix_tree_preload_end();
1211 }
1212 if (error) {
1213 mem_cgroup_uncharge_cache_page(page);
1214 goto decused;
1215 }
Hugh Dickins54af60422011-08-03 16:21:24 -07001216 lru_cache_add_anon(page);
1217
1218 spin_lock(&info->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 info->alloced++;
Hugh Dickins54af60422011-08-03 16:21:24 -07001220 inode->i_blocks += BLOCKS_PER_PAGE;
1221 shmem_recalc_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 spin_unlock(&info->lock);
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001223 alloced = true;
Hugh Dickins54af60422011-08-03 16:21:24 -07001224
Hugh Dickinsec9516f2012-05-29 15:06:39 -07001225 /*
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001226 * Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
1227 */
1228 if (sgp == SGP_FALLOC)
1229 sgp = SGP_WRITE;
1230clear:
1231 /*
1232 * Let SGP_WRITE caller clear ends if write does not fill page;
1233 * but SGP_FALLOC on a page fallocated earlier must initialize
1234 * it now, lest undo on failure cancel our earlier guarantee.
Hugh Dickinsec9516f2012-05-29 15:06:39 -07001235 */
1236 if (sgp != SGP_WRITE) {
1237 clear_highpage(page);
1238 flush_dcache_page(page);
1239 SetPageUptodate(page);
1240 }
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001241 if (sgp == SGP_DIRTY)
Hugh Dickins27ab7002011-07-25 17:12:36 -07001242 set_page_dirty(page);
Hugh Dickins59a16ea2011-05-11 15:13:38 -07001243 }
Hugh Dickinsbde05d12012-05-29 15:06:38 -07001244
Hugh Dickins54af60422011-08-03 16:21:24 -07001245 /* Perhaps the file has been truncated since we checked */
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001246 if (sgp != SGP_WRITE && sgp != SGP_FALLOC &&
Hugh Dickins54af60422011-08-03 16:21:24 -07001247 ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
1248 error = -EINVAL;
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001249 if (alloced)
1250 goto trunc;
1251 else
1252 goto failed;
Shaohua Liff36b8012010-08-09 17:19:06 -07001253 }
Hugh Dickins54af60422011-08-03 16:21:24 -07001254 *pagep = page;
1255 return 0;
Nick Piggind00806b2007-07-19 01:46:57 -07001256
Nick Piggind0217ac2007-07-19 01:47:03 -07001257 /*
Hugh Dickins54af60422011-08-03 16:21:24 -07001258 * Error recovery.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 */
Hugh Dickins54af60422011-08-03 16:21:24 -07001260trunc:
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001261 info = SHMEM_I(inode);
Hugh Dickins54af60422011-08-03 16:21:24 -07001262 ClearPageDirty(page);
1263 delete_from_page_cache(page);
1264 spin_lock(&info->lock);
1265 info->alloced--;
1266 inode->i_blocks -= BLOCKS_PER_PAGE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 spin_unlock(&info->lock);
Hugh Dickins54af60422011-08-03 16:21:24 -07001268decused:
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001269 sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins54af60422011-08-03 16:21:24 -07001270 if (sbinfo->max_blocks)
1271 percpu_counter_add(&sbinfo->used_blocks, -1);
1272unacct:
1273 shmem_unacct_blocks(info->flags, 1);
1274failed:
Hugh Dickinsd1899222012-07-11 14:02:47 -07001275 if (swap.val && error != -EINVAL &&
1276 !shmem_confirm_swap(mapping, index, swap))
1277 error = -EEXIST;
1278unlock:
Hugh Dickins27ab7002011-07-25 17:12:36 -07001279 if (page) {
Hugh Dickins54af60422011-08-03 16:21:24 -07001280 unlock_page(page);
Hugh Dickins27ab7002011-07-25 17:12:36 -07001281 page_cache_release(page);
Hugh Dickins54af60422011-08-03 16:21:24 -07001282 }
1283 if (error == -ENOSPC && !once++) {
1284 info = SHMEM_I(inode);
1285 spin_lock(&info->lock);
1286 shmem_recalc_inode(inode);
1287 spin_unlock(&info->lock);
Hugh Dickins27ab7002011-07-25 17:12:36 -07001288 goto repeat;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001289 }
Hugh Dickinsd1899222012-07-11 14:02:47 -07001290 if (error == -EEXIST) /* from above or from radix_tree_insert */
Hugh Dickins54af60422011-08-03 16:21:24 -07001291 goto repeat;
1292 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293}
1294
1295static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1296{
Al Viro496ad9a2013-01-23 17:07:38 -05001297 struct inode *inode = file_inode(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298 int error;
Hugh Dickins68da9f02011-07-25 17:12:34 -07001299 int ret = VM_FAULT_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301 error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
1302 if (error)
1303 return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
Hugh Dickins68da9f02011-07-25 17:12:34 -07001304
Ying Han456f9982011-05-26 16:25:38 -07001305 if (ret & VM_FAULT_MAJOR) {
1306 count_vm_event(PGMAJFAULT);
1307 mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
1308 }
Hugh Dickins68da9f02011-07-25 17:12:34 -07001309 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310}
1311
1312#ifdef CONFIG_NUMA
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001313static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314{
Al Viro496ad9a2013-01-23 17:07:38 -05001315 struct inode *inode = file_inode(vma->vm_file);
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001316 return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317}
1318
Adrian Bunkd8dc74f2007-10-16 01:26:26 -07001319static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
1320 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321{
Al Viro496ad9a2013-01-23 17:07:38 -05001322 struct inode *inode = file_inode(vma->vm_file);
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001323 pgoff_t index;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001325 index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
1326 return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327}
1328#endif
1329
1330int shmem_lock(struct file *file, int lock, struct user_struct *user)
1331{
Al Viro496ad9a2013-01-23 17:07:38 -05001332 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 struct shmem_inode_info *info = SHMEM_I(inode);
1334 int retval = -ENOMEM;
1335
1336 spin_lock(&info->lock);
1337 if (lock && !(info->flags & VM_LOCKED)) {
1338 if (!user_shm_lock(inode->i_size, user))
1339 goto out_nomem;
1340 info->flags |= VM_LOCKED;
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -07001341 mapping_set_unevictable(file->f_mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342 }
1343 if (!lock && (info->flags & VM_LOCKED) && user) {
1344 user_shm_unlock(inode->i_size, user);
1345 info->flags &= ~VM_LOCKED;
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -07001346 mapping_clear_unevictable(file->f_mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347 }
1348 retval = 0;
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -07001349
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350out_nomem:
1351 spin_unlock(&info->lock);
1352 return retval;
1353}
1354
Adrian Bunk9b83a6a2007-02-28 20:11:03 -08001355static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356{
1357 file_accessed(file);
1358 vma->vm_ops = &shmem_vm_ops;
1359 return 0;
1360}
1361
Dmitry Monakhov454abaf2010-03-04 17:32:18 +03001362static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir,
Al Viro09208d12011-07-26 03:15:03 -04001363 umode_t mode, dev_t dev, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364{
1365 struct inode *inode;
1366 struct shmem_inode_info *info;
1367 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
1368
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001369 if (shmem_reserve_inode(sb))
1370 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371
1372 inode = new_inode(sb);
1373 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -04001374 inode->i_ino = get_next_ino();
Dmitry Monakhov454abaf2010-03-04 17:32:18 +03001375 inode_init_owner(inode, dir, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376 inode->i_blocks = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
1378 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
David M. Grimes91828a42006-10-17 00:09:45 -07001379 inode->i_generation = get_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380 info = SHMEM_I(inode);
1381 memset(info, 0, (char *)inode - (char *)info);
1382 spin_lock_init(&info->lock);
Hugh Dickins0b0a0802009-02-24 20:51:52 +00001383 info->flags = flags & VM_NORESERVE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 INIT_LIST_HEAD(&info->swaplist);
Aristeu Rozanski38f38652012-08-23 16:53:28 -04001385 simple_xattrs_init(&info->xattrs);
Al Viro72c04902009-06-24 16:58:48 -04001386 cache_no_acl(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387
1388 switch (mode & S_IFMT) {
1389 default:
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001390 inode->i_op = &shmem_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391 init_special_inode(inode, mode, dev);
1392 break;
1393 case S_IFREG:
Hugh Dickins14fcc232008-07-28 15:46:19 -07001394 inode->i_mapping->a_ops = &shmem_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395 inode->i_op = &shmem_inode_operations;
1396 inode->i_fop = &shmem_file_operations;
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001397 mpol_shared_policy_init(&info->policy,
1398 shmem_get_sbmpol(sbinfo));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 break;
1400 case S_IFDIR:
Dave Hansend8c76e62006-09-30 23:29:04 -07001401 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402 /* Some things misbehave if size == 0 on a directory */
1403 inode->i_size = 2 * BOGO_DIRENT_SIZE;
1404 inode->i_op = &shmem_dir_inode_operations;
1405 inode->i_fop = &simple_dir_operations;
1406 break;
1407 case S_IFLNK:
1408 /*
1409 * Must not load anything in the rbtree,
1410 * mpol_free_shared_policy will not be called.
1411 */
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07001412 mpol_shared_policy_init(&info->policy, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413 break;
1414 }
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001415 } else
1416 shmem_free_inode(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 return inode;
1418}
1419
1420#ifdef CONFIG_TMPFS
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08001421static const struct inode_operations shmem_symlink_inode_operations;
Hugh Dickins69f07ec2011-08-03 16:21:26 -07001422static const struct inode_operations shmem_short_symlink_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07001424#ifdef CONFIG_TMPFS_XATTR
1425static int shmem_initxattrs(struct inode *, const struct xattr *, void *);
1426#else
1427#define shmem_initxattrs NULL
1428#endif
1429
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430static int
Nick Piggin800d15a2007-10-16 01:25:03 -07001431shmem_write_begin(struct file *file, struct address_space *mapping,
1432 loff_t pos, unsigned len, unsigned flags,
1433 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434{
Nick Piggin800d15a2007-10-16 01:25:03 -07001435 struct inode *inode = mapping->host;
1436 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
Nick Piggin800d15a2007-10-16 01:25:03 -07001437 return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL);
1438}
1439
1440static int
1441shmem_write_end(struct file *file, struct address_space *mapping,
1442 loff_t pos, unsigned len, unsigned copied,
1443 struct page *page, void *fsdata)
1444{
1445 struct inode *inode = mapping->host;
1446
Hugh Dickinsd3602442008-02-04 22:28:44 -08001447 if (pos + copied > inode->i_size)
1448 i_size_write(inode, pos + copied);
1449
Hugh Dickinsec9516f2012-05-29 15:06:39 -07001450 if (!PageUptodate(page)) {
1451 if (copied < PAGE_CACHE_SIZE) {
1452 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
1453 zero_user_segments(page, 0, from,
1454 from + copied, PAGE_CACHE_SIZE);
1455 }
1456 SetPageUptodate(page);
1457 }
Nick Piggin800d15a2007-10-16 01:25:03 -07001458 set_page_dirty(page);
Wu Fengguang6746aff2009-09-16 11:50:14 +02001459 unlock_page(page);
Nick Piggin800d15a2007-10-16 01:25:03 -07001460 page_cache_release(page);
1461
Nick Piggin800d15a2007-10-16 01:25:03 -07001462 return copied;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463}
1464
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
1466{
Al Viro496ad9a2013-01-23 17:07:38 -05001467 struct inode *inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 struct address_space *mapping = inode->i_mapping;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001469 pgoff_t index;
1470 unsigned long offset;
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001471 enum sgp_type sgp = SGP_READ;
1472
1473 /*
1474 * Might this read be for a stacking filesystem? Then when reading
1475 * holes of a sparse file, we actually need to allocate those pages,
1476 * and even mark them dirty, so it cannot exceed the max_blocks limit.
1477 */
1478 if (segment_eq(get_fs(), KERNEL_DS))
1479 sgp = SGP_DIRTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480
1481 index = *ppos >> PAGE_CACHE_SHIFT;
1482 offset = *ppos & ~PAGE_CACHE_MASK;
1483
1484 for (;;) {
1485 struct page *page = NULL;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001486 pgoff_t end_index;
1487 unsigned long nr, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 loff_t i_size = i_size_read(inode);
1489
1490 end_index = i_size >> PAGE_CACHE_SHIFT;
1491 if (index > end_index)
1492 break;
1493 if (index == end_index) {
1494 nr = i_size & ~PAGE_CACHE_MASK;
1495 if (nr <= offset)
1496 break;
1497 }
1498
Hugh Dickinsa0ee5ec2008-02-04 22:28:51 -08001499 desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 if (desc->error) {
1501 if (desc->error == -EINVAL)
1502 desc->error = 0;
1503 break;
1504 }
Hugh Dickinsd3602442008-02-04 22:28:44 -08001505 if (page)
1506 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507
1508 /*
1509 * We must evaluate after, since reads (unlike writes)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001510 * are called without i_mutex protection against truncate
Linus Torvalds1da177e2005-04-16 15:20:36 -07001511 */
1512 nr = PAGE_CACHE_SIZE;
1513 i_size = i_size_read(inode);
1514 end_index = i_size >> PAGE_CACHE_SHIFT;
1515 if (index == end_index) {
1516 nr = i_size & ~PAGE_CACHE_MASK;
1517 if (nr <= offset) {
1518 if (page)
1519 page_cache_release(page);
1520 break;
1521 }
1522 }
1523 nr -= offset;
1524
1525 if (page) {
1526 /*
1527 * If users can be writing to this page using arbitrary
1528 * virtual addresses, take care about potential aliasing
1529 * before reading the page on the kernel side.
1530 */
1531 if (mapping_writably_mapped(mapping))
1532 flush_dcache_page(page);
1533 /*
1534 * Mark the page accessed if we read the beginning.
1535 */
1536 if (!offset)
1537 mark_page_accessed(page);
Nick Pigginb5810032005-10-29 18:16:12 -07001538 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539 page = ZERO_PAGE(0);
Nick Pigginb5810032005-10-29 18:16:12 -07001540 page_cache_get(page);
1541 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542
1543 /*
1544 * Ok, we have the page, and it's up-to-date, so
1545 * now we can copy it to user space...
1546 *
1547 * The actor routine returns how many bytes were actually used..
1548 * NOTE! This may not be the same as how much of a user buffer
1549 * we filled up (we may be padding etc), so we can only update
1550 * "pos" here (the actor routine has to update the user buffer
1551 * pointers and the remaining count).
1552 */
1553 ret = actor(desc, page, offset, nr);
1554 offset += ret;
1555 index += offset >> PAGE_CACHE_SHIFT;
1556 offset &= ~PAGE_CACHE_MASK;
1557
1558 page_cache_release(page);
1559 if (ret != nr || !desc->count)
1560 break;
1561
1562 cond_resched();
1563 }
1564
1565 *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
1566 file_accessed(filp);
1567}
1568
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001569static ssize_t shmem_file_aio_read(struct kiocb *iocb,
1570 const struct iovec *iov, unsigned long nr_segs, loff_t pos)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571{
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001572 struct file *filp = iocb->ki_filp;
1573 ssize_t retval;
1574 unsigned long seg;
1575 size_t count;
1576 loff_t *ppos = &iocb->ki_pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001578 retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
1579 if (retval)
1580 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001581
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001582 for (seg = 0; seg < nr_segs; seg++) {
1583 read_descriptor_t desc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001584
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07001585 desc.written = 0;
1586 desc.arg.buf = iov[seg].iov_base;
1587 desc.count = iov[seg].iov_len;
1588 if (desc.count == 0)
1589 continue;
1590 desc.error = 0;
1591 do_shmem_file_read(filp, ppos, &desc, file_read_actor);
1592 retval += desc.written;
1593 if (desc.error) {
1594 retval = retval ?: desc.error;
1595 break;
1596 }
1597 if (desc.count > 0)
1598 break;
1599 }
1600 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601}
1602
Hugh Dickins708e3502011-07-25 17:12:32 -07001603static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
1604 struct pipe_inode_info *pipe, size_t len,
1605 unsigned int flags)
1606{
1607 struct address_space *mapping = in->f_mapping;
Hugh Dickins71f0e072011-07-25 17:12:33 -07001608 struct inode *inode = mapping->host;
Hugh Dickins708e3502011-07-25 17:12:32 -07001609 unsigned int loff, nr_pages, req_pages;
1610 struct page *pages[PIPE_DEF_BUFFERS];
1611 struct partial_page partial[PIPE_DEF_BUFFERS];
1612 struct page *page;
1613 pgoff_t index, end_index;
1614 loff_t isize, left;
1615 int error, page_nr;
1616 struct splice_pipe_desc spd = {
1617 .pages = pages,
1618 .partial = partial,
Eric Dumazet047fe362012-06-12 15:24:40 +02001619 .nr_pages_max = PIPE_DEF_BUFFERS,
Hugh Dickins708e3502011-07-25 17:12:32 -07001620 .flags = flags,
1621 .ops = &page_cache_pipe_buf_ops,
1622 .spd_release = spd_release_page,
1623 };
1624
Hugh Dickins71f0e072011-07-25 17:12:33 -07001625 isize = i_size_read(inode);
Hugh Dickins708e3502011-07-25 17:12:32 -07001626 if (unlikely(*ppos >= isize))
1627 return 0;
1628
1629 left = isize - *ppos;
1630 if (unlikely(left < len))
1631 len = left;
1632
1633 if (splice_grow_spd(pipe, &spd))
1634 return -ENOMEM;
1635
1636 index = *ppos >> PAGE_CACHE_SHIFT;
1637 loff = *ppos & ~PAGE_CACHE_MASK;
1638 req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1639 nr_pages = min(req_pages, pipe->buffers);
1640
Hugh Dickins708e3502011-07-25 17:12:32 -07001641 spd.nr_pages = find_get_pages_contig(mapping, index,
1642 nr_pages, spd.pages);
1643 index += spd.nr_pages;
Hugh Dickins708e3502011-07-25 17:12:32 -07001644 error = 0;
Hugh Dickins71f0e072011-07-25 17:12:33 -07001645
Hugh Dickins708e3502011-07-25 17:12:32 -07001646 while (spd.nr_pages < nr_pages) {
Hugh Dickins71f0e072011-07-25 17:12:33 -07001647 error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL);
1648 if (error)
1649 break;
1650 unlock_page(page);
Hugh Dickins708e3502011-07-25 17:12:32 -07001651 spd.pages[spd.nr_pages++] = page;
1652 index++;
1653 }
1654
Hugh Dickins708e3502011-07-25 17:12:32 -07001655 index = *ppos >> PAGE_CACHE_SHIFT;
1656 nr_pages = spd.nr_pages;
1657 spd.nr_pages = 0;
Hugh Dickins71f0e072011-07-25 17:12:33 -07001658
Hugh Dickins708e3502011-07-25 17:12:32 -07001659 for (page_nr = 0; page_nr < nr_pages; page_nr++) {
1660 unsigned int this_len;
1661
1662 if (!len)
1663 break;
1664
Hugh Dickins708e3502011-07-25 17:12:32 -07001665 this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
1666 page = spd.pages[page_nr];
1667
Hugh Dickins71f0e072011-07-25 17:12:33 -07001668 if (!PageUptodate(page) || page->mapping != mapping) {
Hugh Dickins71f0e072011-07-25 17:12:33 -07001669 error = shmem_getpage(inode, index, &page,
1670 SGP_CACHE, NULL);
1671 if (error)
Hugh Dickins708e3502011-07-25 17:12:32 -07001672 break;
Hugh Dickins71f0e072011-07-25 17:12:33 -07001673 unlock_page(page);
1674 page_cache_release(spd.pages[page_nr]);
1675 spd.pages[page_nr] = page;
Hugh Dickins708e3502011-07-25 17:12:32 -07001676 }
Hugh Dickins71f0e072011-07-25 17:12:33 -07001677
1678 isize = i_size_read(inode);
Hugh Dickins708e3502011-07-25 17:12:32 -07001679 end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
1680 if (unlikely(!isize || index > end_index))
1681 break;
1682
Hugh Dickins708e3502011-07-25 17:12:32 -07001683 if (end_index == index) {
1684 unsigned int plen;
1685
Hugh Dickins708e3502011-07-25 17:12:32 -07001686 plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
1687 if (plen <= loff)
1688 break;
1689
Hugh Dickins708e3502011-07-25 17:12:32 -07001690 this_len = min(this_len, plen - loff);
1691 len = this_len;
1692 }
1693
1694 spd.partial[page_nr].offset = loff;
1695 spd.partial[page_nr].len = this_len;
1696 len -= this_len;
1697 loff = 0;
1698 spd.nr_pages++;
1699 index++;
1700 }
1701
Hugh Dickins708e3502011-07-25 17:12:32 -07001702 while (page_nr < nr_pages)
1703 page_cache_release(spd.pages[page_nr++]);
Hugh Dickins708e3502011-07-25 17:12:32 -07001704
1705 if (spd.nr_pages)
1706 error = splice_to_pipe(pipe, &spd);
1707
Eric Dumazet047fe362012-06-12 15:24:40 +02001708 splice_shrink_spd(&spd);
Hugh Dickins708e3502011-07-25 17:12:32 -07001709
1710 if (error > 0) {
1711 *ppos += error;
1712 file_accessed(in);
1713 }
1714 return error;
1715}
1716
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001717/*
1718 * llseek SEEK_DATA or SEEK_HOLE through the radix_tree.
1719 */
1720static pgoff_t shmem_seek_hole_data(struct address_space *mapping,
Andrew Morton965c8e52012-12-17 15:59:39 -08001721 pgoff_t index, pgoff_t end, int whence)
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001722{
1723 struct page *page;
1724 struct pagevec pvec;
1725 pgoff_t indices[PAGEVEC_SIZE];
1726 bool done = false;
1727 int i;
1728
1729 pagevec_init(&pvec, 0);
1730 pvec.nr = 1; /* start small: we may be there already */
1731 while (!done) {
1732 pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
1733 pvec.nr, pvec.pages, indices);
1734 if (!pvec.nr) {
Andrew Morton965c8e52012-12-17 15:59:39 -08001735 if (whence == SEEK_DATA)
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001736 index = end;
1737 break;
1738 }
1739 for (i = 0; i < pvec.nr; i++, index++) {
1740 if (index < indices[i]) {
Andrew Morton965c8e52012-12-17 15:59:39 -08001741 if (whence == SEEK_HOLE) {
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001742 done = true;
1743 break;
1744 }
1745 index = indices[i];
1746 }
1747 page = pvec.pages[i];
1748 if (page && !radix_tree_exceptional_entry(page)) {
1749 if (!PageUptodate(page))
1750 page = NULL;
1751 }
1752 if (index >= end ||
Andrew Morton965c8e52012-12-17 15:59:39 -08001753 (page && whence == SEEK_DATA) ||
1754 (!page && whence == SEEK_HOLE)) {
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001755 done = true;
1756 break;
1757 }
1758 }
1759 shmem_deswap_pagevec(&pvec);
1760 pagevec_release(&pvec);
1761 pvec.nr = PAGEVEC_SIZE;
1762 cond_resched();
1763 }
1764 return index;
1765}
1766
Andrew Morton965c8e52012-12-17 15:59:39 -08001767static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence)
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001768{
1769 struct address_space *mapping = file->f_mapping;
1770 struct inode *inode = mapping->host;
1771 pgoff_t start, end;
1772 loff_t new_offset;
1773
Andrew Morton965c8e52012-12-17 15:59:39 -08001774 if (whence != SEEK_DATA && whence != SEEK_HOLE)
1775 return generic_file_llseek_size(file, offset, whence,
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001776 MAX_LFS_FILESIZE, i_size_read(inode));
1777 mutex_lock(&inode->i_mutex);
1778 /* We're holding i_mutex so we can access i_size directly */
1779
1780 if (offset < 0)
1781 offset = -EINVAL;
1782 else if (offset >= inode->i_size)
1783 offset = -ENXIO;
1784 else {
1785 start = offset >> PAGE_CACHE_SHIFT;
1786 end = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
Andrew Morton965c8e52012-12-17 15:59:39 -08001787 new_offset = shmem_seek_hole_data(mapping, start, end, whence);
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001788 new_offset <<= PAGE_CACHE_SHIFT;
1789 if (new_offset > offset) {
1790 if (new_offset < inode->i_size)
1791 offset = new_offset;
Andrew Morton965c8e52012-12-17 15:59:39 -08001792 else if (whence == SEEK_DATA)
Hugh Dickins220f2ac2012-12-12 13:52:21 -08001793 offset = -ENXIO;
1794 else
1795 offset = inode->i_size;
1796 }
1797 }
1798
1799 if (offset >= 0 && offset != file->f_pos) {
1800 file->f_pos = offset;
1801 file->f_version = 0;
1802 }
1803 mutex_unlock(&inode->i_mutex);
1804 return offset;
1805}
1806
Hugh Dickins83e4fa92012-05-29 15:06:40 -07001807static long shmem_fallocate(struct file *file, int mode, loff_t offset,
1808 loff_t len)
1809{
Al Viro496ad9a2013-01-23 17:07:38 -05001810 struct inode *inode = file_inode(file);
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001811 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
Hugh Dickins1aac1402012-05-29 15:06:42 -07001812 struct shmem_falloc shmem_falloc;
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001813 pgoff_t start, index, end;
1814 int error;
Hugh Dickins83e4fa92012-05-29 15:06:40 -07001815
1816 mutex_lock(&inode->i_mutex);
1817
1818 if (mode & FALLOC_FL_PUNCH_HOLE) {
1819 struct address_space *mapping = file->f_mapping;
1820 loff_t unmap_start = round_up(offset, PAGE_SIZE);
1821 loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1;
1822
1823 if ((u64)unmap_end > (u64)unmap_start)
1824 unmap_mapping_range(mapping, unmap_start,
1825 1 + unmap_end - unmap_start, 0);
1826 shmem_truncate_range(inode, offset, offset + len - 1);
1827 /* No need to unmap again: hole-punching leaves COWed pages */
1828 error = 0;
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001829 goto out;
Hugh Dickins83e4fa92012-05-29 15:06:40 -07001830 }
1831
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001832 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
1833 error = inode_newsize_ok(inode, offset + len);
1834 if (error)
1835 goto out;
1836
1837 start = offset >> PAGE_CACHE_SHIFT;
1838 end = (offset + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1839 /* Try to avoid a swapstorm if len is impossible to satisfy */
1840 if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) {
1841 error = -ENOSPC;
1842 goto out;
1843 }
1844
Hugh Dickins1aac1402012-05-29 15:06:42 -07001845 shmem_falloc.start = start;
1846 shmem_falloc.next = start;
1847 shmem_falloc.nr_falloced = 0;
1848 shmem_falloc.nr_unswapped = 0;
1849 spin_lock(&inode->i_lock);
1850 inode->i_private = &shmem_falloc;
1851 spin_unlock(&inode->i_lock);
1852
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001853 for (index = start; index < end; index++) {
1854 struct page *page;
1855
1856 /*
1857 * Good, the fallocate(2) manpage permits EINTR: we may have
1858 * been interrupted because we are using up too much memory.
1859 */
1860 if (signal_pending(current))
1861 error = -EINTR;
Hugh Dickins1aac1402012-05-29 15:06:42 -07001862 else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced)
1863 error = -ENOMEM;
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001864 else
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001865 error = shmem_getpage(inode, index, &page, SGP_FALLOC,
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001866 NULL);
1867 if (error) {
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001868 /* Remove the !PageUptodate pages we added */
1869 shmem_undo_range(inode,
1870 (loff_t)start << PAGE_CACHE_SHIFT,
1871 (loff_t)index << PAGE_CACHE_SHIFT, true);
Hugh Dickins1aac1402012-05-29 15:06:42 -07001872 goto undone;
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001873 }
1874
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001875 /*
Hugh Dickins1aac1402012-05-29 15:06:42 -07001876 * Inform shmem_writepage() how far we have reached.
1877 * No need for lock or barrier: we have the page lock.
1878 */
1879 shmem_falloc.next++;
1880 if (!PageUptodate(page))
1881 shmem_falloc.nr_falloced++;
1882
1883 /*
Hugh Dickins1635f6a2012-05-29 15:06:42 -07001884 * If !PageUptodate, leave it that way so that freeable pages
1885 * can be recognized if we need to rollback on error later.
1886 * But set_page_dirty so that memory pressure will swap rather
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001887 * than free the pages we are allocating (and SGP_CACHE pages
1888 * might still be clean: we now need to mark those dirty too).
1889 */
1890 set_page_dirty(page);
1891 unlock_page(page);
1892 page_cache_release(page);
1893 cond_resched();
1894 }
1895
1896 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
1897 i_size_write(inode, offset + len);
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001898 inode->i_ctime = CURRENT_TIME;
Hugh Dickins1aac1402012-05-29 15:06:42 -07001899undone:
1900 spin_lock(&inode->i_lock);
1901 inode->i_private = NULL;
1902 spin_unlock(&inode->i_lock);
Hugh Dickinse2d12e22012-05-29 15:06:41 -07001903out:
Hugh Dickins83e4fa92012-05-29 15:06:40 -07001904 mutex_unlock(&inode->i_mutex);
1905 return error;
1906}
1907
David Howells726c3342006-06-23 02:02:58 -07001908static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001909{
David Howells726c3342006-06-23 02:02:58 -07001910 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911
1912 buf->f_type = TMPFS_MAGIC;
1913 buf->f_bsize = PAGE_CACHE_SIZE;
1914 buf->f_namelen = NAME_MAX;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001915 if (sbinfo->max_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001916 buf->f_blocks = sbinfo->max_blocks;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07001917 buf->f_bavail =
1918 buf->f_bfree = sbinfo->max_blocks -
1919 percpu_counter_sum(&sbinfo->used_blocks);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07001920 }
1921 if (sbinfo->max_inodes) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922 buf->f_files = sbinfo->max_inodes;
1923 buf->f_ffree = sbinfo->free_inodes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 }
1925 /* else leave those fields 0 like simple_statfs */
1926 return 0;
1927}
1928
1929/*
1930 * File creation. Allocate an inode, and we're done..
1931 */
1932static int
Al Viro1a67aaf2011-07-26 01:52:52 -04001933shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934{
Hugh Dickins0b0a0802009-02-24 20:51:52 +00001935 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001936 int error = -ENOSPC;
1937
Dmitry Monakhov454abaf2010-03-04 17:32:18 +03001938 inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 if (inode) {
Eric Paris2a7dba32011-02-01 11:05:39 -05001940 error = security_inode_init_security(inode, dir,
Mimi Zohar9d8f13b2011-06-06 15:29:25 -04001941 &dentry->d_name,
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07001942 shmem_initxattrs, NULL);
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001943 if (error) {
1944 if (error != -EOPNOTSUPP) {
1945 iput(inode);
1946 return error;
1947 }
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001948 }
Christoph Hellwig1c7c4742009-11-03 16:44:44 +01001949#ifdef CONFIG_TMPFS_POSIX_ACL
1950 error = generic_acl_init(inode, dir);
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07001951 if (error) {
1952 iput(inode);
1953 return error;
Stephen Smalley570bc1c2005-09-09 13:01:43 -07001954 }
Al Viro718deb62009-12-16 19:35:36 -05001955#else
1956 error = 0;
Christoph Hellwig1c7c4742009-11-03 16:44:44 +01001957#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 dir->i_size += BOGO_DIRENT_SIZE;
1959 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1960 d_instantiate(dentry, inode);
1961 dget(dentry); /* Extra count - pin the dentry in core */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962 }
1963 return error;
1964}
1965
Al Viro18bb1db2011-07-26 01:41:39 -04001966static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967{
1968 int error;
1969
1970 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
1971 return error;
Dave Hansend8c76e62006-09-30 23:29:04 -07001972 inc_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 return 0;
1974}
1975
Al Viro4acdaf22011-07-26 01:42:34 -04001976static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode,
Al Viroebfc3b42012-06-10 18:05:36 -04001977 bool excl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978{
1979 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
1980}
1981
1982/*
1983 * Link a file..
1984 */
1985static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1986{
1987 struct inode *inode = old_dentry->d_inode;
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001988 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001989
1990 /*
1991 * No ordinary (disk based) filesystem counts links as inodes;
1992 * but each new link needs a new dentry, pinning lowmem, and
1993 * tmpfs dentries cannot be pruned until they are unlinked.
1994 */
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08001995 ret = shmem_reserve_inode(inode->i_sb);
1996 if (ret)
1997 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001998
1999 dir->i_size += BOGO_DIRENT_SIZE;
2000 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -07002001 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -04002002 ihold(inode); /* New dentry reference */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 dget(dentry); /* Extra pinning count for the created dentry */
2004 d_instantiate(dentry, inode);
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08002005out:
2006 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007}
2008
2009static int shmem_unlink(struct inode *dir, struct dentry *dentry)
2010{
2011 struct inode *inode = dentry->d_inode;
2012
Pavel Emelyanov5b04c682008-02-04 22:28:47 -08002013 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
2014 shmem_free_inode(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002015
2016 dir->i_size -= BOGO_DIRENT_SIZE;
2017 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -07002018 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002019 dput(dentry); /* Undo the count from "create" - this does all the work */
2020 return 0;
2021}
2022
2023static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
2024{
2025 if (!simple_empty(dentry))
2026 return -ENOTEMPTY;
2027
Dave Hansen9a53c3a2006-09-30 23:29:03 -07002028 drop_nlink(dentry->d_inode);
2029 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002030 return shmem_unlink(dir, dentry);
2031}
2032
2033/*
2034 * The VFS layer already does all the dentry stuff for rename,
2035 * we just have to decrement the usage count for the target if
2036 * it exists so that the VFS layer correctly free's it when it
2037 * gets overwritten.
2038 */
2039static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
2040{
2041 struct inode *inode = old_dentry->d_inode;
2042 int they_are_dirs = S_ISDIR(inode->i_mode);
2043
2044 if (!simple_empty(new_dentry))
2045 return -ENOTEMPTY;
2046
2047 if (new_dentry->d_inode) {
2048 (void) shmem_unlink(new_dir, new_dentry);
2049 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -07002050 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002051 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -07002052 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -07002053 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002054 }
2055
2056 old_dir->i_size -= BOGO_DIRENT_SIZE;
2057 new_dir->i_size += BOGO_DIRENT_SIZE;
2058 old_dir->i_ctime = old_dir->i_mtime =
2059 new_dir->i_ctime = new_dir->i_mtime =
2060 inode->i_ctime = CURRENT_TIME;
2061 return 0;
2062}
2063
2064static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
2065{
2066 int error;
2067 int len;
2068 struct inode *inode;
Hugh Dickins9276aad2011-07-25 17:12:34 -07002069 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070 char *kaddr;
2071 struct shmem_inode_info *info;
2072
2073 len = strlen(symname) + 1;
2074 if (len > PAGE_CACHE_SIZE)
2075 return -ENAMETOOLONG;
2076
Dmitry Monakhov454abaf2010-03-04 17:32:18 +03002077 inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002078 if (!inode)
2079 return -ENOSPC;
2080
Mimi Zohar9d8f13b2011-06-06 15:29:25 -04002081 error = security_inode_init_security(inode, dir, &dentry->d_name,
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07002082 shmem_initxattrs, NULL);
Stephen Smalley570bc1c2005-09-09 13:01:43 -07002083 if (error) {
2084 if (error != -EOPNOTSUPP) {
2085 iput(inode);
2086 return error;
2087 }
2088 error = 0;
2089 }
2090
Linus Torvalds1da177e2005-04-16 15:20:36 -07002091 info = SHMEM_I(inode);
2092 inode->i_size = len-1;
Hugh Dickins69f07ec2011-08-03 16:21:26 -07002093 if (len <= SHORT_SYMLINK_LEN) {
2094 info->symlink = kmemdup(symname, len, GFP_KERNEL);
2095 if (!info->symlink) {
2096 iput(inode);
2097 return -ENOMEM;
2098 }
2099 inode->i_op = &shmem_short_symlink_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100 } else {
2101 error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
2102 if (error) {
2103 iput(inode);
2104 return error;
2105 }
Hugh Dickins14fcc232008-07-28 15:46:19 -07002106 inode->i_mapping->a_ops = &shmem_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002107 inode->i_op = &shmem_symlink_inode_operations;
Cong Wang9b04c5f2011-11-25 23:14:39 +08002108 kaddr = kmap_atomic(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109 memcpy(kaddr, symname, len);
Cong Wang9b04c5f2011-11-25 23:14:39 +08002110 kunmap_atomic(kaddr);
Hugh Dickinsec9516f2012-05-29 15:06:39 -07002111 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112 set_page_dirty(page);
Wu Fengguang6746aff2009-09-16 11:50:14 +02002113 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002114 page_cache_release(page);
2115 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002116 dir->i_size += BOGO_DIRENT_SIZE;
2117 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
2118 d_instantiate(dentry, inode);
2119 dget(dentry);
2120 return 0;
2121}
2122
Hugh Dickins69f07ec2011-08-03 16:21:26 -07002123static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124{
Hugh Dickins69f07ec2011-08-03 16:21:26 -07002125 nd_set_link(nd, SHMEM_I(dentry->d_inode)->symlink);
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002126 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002127}
2128
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002129static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130{
2131 struct page *page = NULL;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002132 int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
2133 nd_set_link(nd, error ? ERR_PTR(error) : kmap(page));
Hugh Dickinsd3602442008-02-04 22:28:44 -08002134 if (page)
2135 unlock_page(page);
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002136 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002137}
2138
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002139static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002140{
2141 if (!IS_ERR(nd_get_link(nd))) {
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002142 struct page *page = cookie;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002143 kunmap(page);
2144 mark_page_accessed(page);
2145 page_cache_release(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002146 }
2147}
2148
Eric Parisb09e0fa2011-05-24 17:12:39 -07002149#ifdef CONFIG_TMPFS_XATTR
2150/*
2151 * Superblocks without xattr inode operations may get some security.* xattr
2152 * support from the LSM "for free". As soon as we have any other xattrs
2153 * like ACLs, we also need to implement the security.* handlers at
2154 * filesystem level, though.
2155 */
2156
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07002157/*
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07002158 * Callback for security_inode_init_security() for acquiring xattrs.
2159 */
2160static int shmem_initxattrs(struct inode *inode,
2161 const struct xattr *xattr_array,
2162 void *fs_info)
2163{
2164 struct shmem_inode_info *info = SHMEM_I(inode);
2165 const struct xattr *xattr;
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002166 struct simple_xattr *new_xattr;
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07002167 size_t len;
2168
2169 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002170 new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len);
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07002171 if (!new_xattr)
2172 return -ENOMEM;
2173
2174 len = strlen(xattr->name) + 1;
2175 new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
2176 GFP_KERNEL);
2177 if (!new_xattr->name) {
2178 kfree(new_xattr);
2179 return -ENOMEM;
2180 }
2181
2182 memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
2183 XATTR_SECURITY_PREFIX_LEN);
2184 memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
2185 xattr->name, len);
2186
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002187 simple_xattr_list_add(&info->xattrs, new_xattr);
Jarkko Sakkinen6d9d88d2012-03-21 16:34:05 -07002188 }
2189
2190 return 0;
2191}
2192
Eric Parisb09e0fa2011-05-24 17:12:39 -07002193static const struct xattr_handler *shmem_xattr_handlers[] = {
2194#ifdef CONFIG_TMPFS_POSIX_ACL
2195 &generic_acl_access_handler,
2196 &generic_acl_default_handler,
2197#endif
2198 NULL
2199};
2200
2201static int shmem_xattr_validate(const char *name)
2202{
2203 struct { const char *prefix; size_t len; } arr[] = {
2204 { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN },
2205 { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN }
2206 };
2207 int i;
2208
2209 for (i = 0; i < ARRAY_SIZE(arr); i++) {
2210 size_t preflen = arr[i].len;
2211 if (strncmp(name, arr[i].prefix, preflen) == 0) {
2212 if (!name[preflen])
2213 return -EINVAL;
2214 return 0;
2215 }
2216 }
2217 return -EOPNOTSUPP;
2218}
2219
2220static ssize_t shmem_getxattr(struct dentry *dentry, const char *name,
2221 void *buffer, size_t size)
2222{
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002223 struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
Eric Parisb09e0fa2011-05-24 17:12:39 -07002224 int err;
2225
2226 /*
2227 * If this is a request for a synthetic attribute in the system.*
2228 * namespace use the generic infrastructure to resolve a handler
2229 * for it via sb->s_xattr.
2230 */
2231 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
2232 return generic_getxattr(dentry, name, buffer, size);
2233
2234 err = shmem_xattr_validate(name);
2235 if (err)
2236 return err;
2237
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002238 return simple_xattr_get(&info->xattrs, name, buffer, size);
Eric Parisb09e0fa2011-05-24 17:12:39 -07002239}
2240
2241static int shmem_setxattr(struct dentry *dentry, const char *name,
2242 const void *value, size_t size, int flags)
2243{
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002244 struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
Eric Parisb09e0fa2011-05-24 17:12:39 -07002245 int err;
2246
2247 /*
2248 * If this is a request for a synthetic attribute in the system.*
2249 * namespace use the generic infrastructure to resolve a handler
2250 * for it via sb->s_xattr.
2251 */
2252 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
2253 return generic_setxattr(dentry, name, value, size, flags);
2254
2255 err = shmem_xattr_validate(name);
2256 if (err)
2257 return err;
2258
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002259 return simple_xattr_set(&info->xattrs, name, value, size, flags);
Eric Parisb09e0fa2011-05-24 17:12:39 -07002260}
2261
2262static int shmem_removexattr(struct dentry *dentry, const char *name)
2263{
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002264 struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
Eric Parisb09e0fa2011-05-24 17:12:39 -07002265 int err;
2266
2267 /*
2268 * If this is a request for a synthetic attribute in the system.*
2269 * namespace use the generic infrastructure to resolve a handler
2270 * for it via sb->s_xattr.
2271 */
2272 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
2273 return generic_removexattr(dentry, name);
2274
2275 err = shmem_xattr_validate(name);
2276 if (err)
2277 return err;
2278
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002279 return simple_xattr_remove(&info->xattrs, name);
Eric Parisb09e0fa2011-05-24 17:12:39 -07002280}
2281
2282static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
2283{
Aristeu Rozanski38f38652012-08-23 16:53:28 -04002284 struct shmem_inode_info *info = SHMEM_I(dentry->d_inode);
2285 return simple_xattr_list(&info->xattrs, buffer, size);
Eric Parisb09e0fa2011-05-24 17:12:39 -07002286}
2287#endif /* CONFIG_TMPFS_XATTR */
2288
Hugh Dickins69f07ec2011-08-03 16:21:26 -07002289static const struct inode_operations shmem_short_symlink_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002290 .readlink = generic_readlink,
Hugh Dickins69f07ec2011-08-03 16:21:26 -07002291 .follow_link = shmem_follow_short_symlink,
Eric Parisb09e0fa2011-05-24 17:12:39 -07002292#ifdef CONFIG_TMPFS_XATTR
2293 .setxattr = shmem_setxattr,
2294 .getxattr = shmem_getxattr,
2295 .listxattr = shmem_listxattr,
2296 .removexattr = shmem_removexattr,
2297#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002298};
2299
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002300static const struct inode_operations shmem_symlink_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301 .readlink = generic_readlink,
2302 .follow_link = shmem_follow_link,
2303 .put_link = shmem_put_link,
Eric Parisb09e0fa2011-05-24 17:12:39 -07002304#ifdef CONFIG_TMPFS_XATTR
2305 .setxattr = shmem_setxattr,
2306 .getxattr = shmem_getxattr,
2307 .listxattr = shmem_listxattr,
2308 .removexattr = shmem_removexattr,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002309#endif
Eric Parisb09e0fa2011-05-24 17:12:39 -07002310};
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002311
David M. Grimes91828a42006-10-17 00:09:45 -07002312static struct dentry *shmem_get_parent(struct dentry *child)
2313{
2314 return ERR_PTR(-ESTALE);
2315}
2316
2317static int shmem_match(struct inode *ino, void *vfh)
2318{
2319 __u32 *fh = vfh;
2320 __u64 inum = fh[2];
2321 inum = (inum << 32) | fh[1];
2322 return ino->i_ino == inum && fh[0] == ino->i_generation;
2323}
2324
Christoph Hellwig480b1162007-10-21 16:42:13 -07002325static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
2326 struct fid *fid, int fh_len, int fh_type)
David M. Grimes91828a42006-10-17 00:09:45 -07002327{
David M. Grimes91828a42006-10-17 00:09:45 -07002328 struct inode *inode;
Christoph Hellwig480b1162007-10-21 16:42:13 -07002329 struct dentry *dentry = NULL;
Hugh Dickins35c2a7f2012-10-07 20:32:51 -07002330 u64 inum;
David M. Grimes91828a42006-10-17 00:09:45 -07002331
Christoph Hellwig480b1162007-10-21 16:42:13 -07002332 if (fh_len < 3)
2333 return NULL;
2334
Hugh Dickins35c2a7f2012-10-07 20:32:51 -07002335 inum = fid->raw[2];
2336 inum = (inum << 32) | fid->raw[1];
2337
Christoph Hellwig480b1162007-10-21 16:42:13 -07002338 inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
2339 shmem_match, fid->raw);
David M. Grimes91828a42006-10-17 00:09:45 -07002340 if (inode) {
Christoph Hellwig480b1162007-10-21 16:42:13 -07002341 dentry = d_find_alias(inode);
David M. Grimes91828a42006-10-17 00:09:45 -07002342 iput(inode);
2343 }
2344
Christoph Hellwig480b1162007-10-21 16:42:13 -07002345 return dentry;
David M. Grimes91828a42006-10-17 00:09:45 -07002346}
2347
Al Virob0b03822012-04-02 14:34:06 -04002348static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len,
2349 struct inode *parent)
David M. Grimes91828a42006-10-17 00:09:45 -07002350{
Aneesh Kumar K.V5fe0c232011-01-29 18:43:25 +05302351 if (*len < 3) {
2352 *len = 3;
Namjae Jeon94e07a752013-02-17 15:48:11 +09002353 return FILEID_INVALID;
Aneesh Kumar K.V5fe0c232011-01-29 18:43:25 +05302354 }
David M. Grimes91828a42006-10-17 00:09:45 -07002355
Al Viro1d3382cb2010-10-23 15:19:20 -04002356 if (inode_unhashed(inode)) {
David M. Grimes91828a42006-10-17 00:09:45 -07002357 /* Unfortunately insert_inode_hash is not idempotent,
2358 * so as we hash inodes here rather than at creation
2359 * time, we need a lock to ensure we only try
2360 * to do it once
2361 */
2362 static DEFINE_SPINLOCK(lock);
2363 spin_lock(&lock);
Al Viro1d3382cb2010-10-23 15:19:20 -04002364 if (inode_unhashed(inode))
David M. Grimes91828a42006-10-17 00:09:45 -07002365 __insert_inode_hash(inode,
2366 inode->i_ino + inode->i_generation);
2367 spin_unlock(&lock);
2368 }
2369
2370 fh[0] = inode->i_generation;
2371 fh[1] = inode->i_ino;
2372 fh[2] = ((__u64)inode->i_ino) >> 32;
2373
2374 *len = 3;
2375 return 1;
2376}
2377
Christoph Hellwig39655162007-10-21 16:42:17 -07002378static const struct export_operations shmem_export_ops = {
David M. Grimes91828a42006-10-17 00:09:45 -07002379 .get_parent = shmem_get_parent,
David M. Grimes91828a42006-10-17 00:09:45 -07002380 .encode_fh = shmem_encode_fh,
Christoph Hellwig480b1162007-10-21 16:42:13 -07002381 .fh_to_dentry = shmem_fh_to_dentry,
David M. Grimes91828a42006-10-17 00:09:45 -07002382};
2383
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002384static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
2385 bool remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002386{
2387 char *this_char, *value, *rest;
Greg Thelen49cd0a52013-02-22 16:36:02 -08002388 struct mempolicy *mpol = NULL;
Eric W. Biederman8751e032012-02-07 16:46:12 -08002389 uid_t uid;
2390 gid_t gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002391
Hugh Dickinsb00dc3a2006-02-21 23:49:47 +00002392 while (options != NULL) {
2393 this_char = options;
2394 for (;;) {
2395 /*
2396 * NUL-terminate this option: unfortunately,
2397 * mount options form a comma-separated list,
2398 * but mpol's nodelist may also contain commas.
2399 */
2400 options = strchr(options, ',');
2401 if (options == NULL)
2402 break;
2403 options++;
2404 if (!isdigit(*options)) {
2405 options[-1] = '\0';
2406 break;
2407 }
2408 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002409 if (!*this_char)
2410 continue;
2411 if ((value = strchr(this_char,'=')) != NULL) {
2412 *value++ = 0;
2413 } else {
2414 printk(KERN_ERR
2415 "tmpfs: No value for mount option '%s'\n",
2416 this_char);
Greg Thelen49cd0a52013-02-22 16:36:02 -08002417 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002418 }
2419
2420 if (!strcmp(this_char,"size")) {
2421 unsigned long long size;
2422 size = memparse(value,&rest);
2423 if (*rest == '%') {
2424 size <<= PAGE_SHIFT;
2425 size *= totalram_pages;
2426 do_div(size, 100);
2427 rest++;
2428 }
2429 if (*rest)
2430 goto bad_val;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002431 sbinfo->max_blocks =
2432 DIV_ROUND_UP(size, PAGE_CACHE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002433 } else if (!strcmp(this_char,"nr_blocks")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002434 sbinfo->max_blocks = memparse(value, &rest);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002435 if (*rest)
2436 goto bad_val;
2437 } else if (!strcmp(this_char,"nr_inodes")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002438 sbinfo->max_inodes = memparse(value, &rest);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002439 if (*rest)
2440 goto bad_val;
2441 } else if (!strcmp(this_char,"mode")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002442 if (remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002443 continue;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002444 sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002445 if (*rest)
2446 goto bad_val;
2447 } else if (!strcmp(this_char,"uid")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002448 if (remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002449 continue;
Eric W. Biederman8751e032012-02-07 16:46:12 -08002450 uid = simple_strtoul(value, &rest, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451 if (*rest)
2452 goto bad_val;
Eric W. Biederman8751e032012-02-07 16:46:12 -08002453 sbinfo->uid = make_kuid(current_user_ns(), uid);
2454 if (!uid_valid(sbinfo->uid))
2455 goto bad_val;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002456 } else if (!strcmp(this_char,"gid")) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002457 if (remount)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002458 continue;
Eric W. Biederman8751e032012-02-07 16:46:12 -08002459 gid = simple_strtoul(value, &rest, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002460 if (*rest)
2461 goto bad_val;
Eric W. Biederman8751e032012-02-07 16:46:12 -08002462 sbinfo->gid = make_kgid(current_user_ns(), gid);
2463 if (!gid_valid(sbinfo->gid))
2464 goto bad_val;
Robin Holt7339ff82006-01-14 13:20:48 -08002465 } else if (!strcmp(this_char,"mpol")) {
Greg Thelen49cd0a52013-02-22 16:36:02 -08002466 mpol_put(mpol);
2467 mpol = NULL;
2468 if (mpol_parse_str(value, &mpol))
Robin Holt7339ff82006-01-14 13:20:48 -08002469 goto bad_val;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002470 } else {
2471 printk(KERN_ERR "tmpfs: Bad mount option %s\n",
2472 this_char);
Greg Thelen49cd0a52013-02-22 16:36:02 -08002473 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002474 }
2475 }
Greg Thelen49cd0a52013-02-22 16:36:02 -08002476 sbinfo->mpol = mpol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002477 return 0;
2478
2479bad_val:
2480 printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
2481 value, this_char);
Greg Thelen49cd0a52013-02-22 16:36:02 -08002482error:
2483 mpol_put(mpol);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002484 return 1;
2485
2486}
2487
2488static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
2489{
2490 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002491 struct shmem_sb_info config = *sbinfo;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002492 unsigned long inodes;
2493 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002494
Greg Thelen5f001102013-02-22 16:36:01 -08002495 config.mpol = NULL;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002496 if (shmem_parse_options(data, &config, true))
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002497 return error;
2498
2499 spin_lock(&sbinfo->stat_lock);
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002500 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
Tim Chen7e496292010-08-09 17:19:05 -07002501 if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002502 goto out;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002503 if (config.max_inodes < inodes)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002504 goto out;
2505 /*
Hugh Dickins54af60422011-08-03 16:21:24 -07002506 * Those tests disallow limited->unlimited while any are in use;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002507 * but we must separately disallow unlimited->limited, because
2508 * in that case we have no record of how much is already in use.
2509 */
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002510 if (config.max_blocks && !sbinfo->max_blocks)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002511 goto out;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002512 if (config.max_inodes && !sbinfo->max_inodes)
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002513 goto out;
2514
2515 error = 0;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002516 sbinfo->max_blocks = config.max_blocks;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002517 sbinfo->max_inodes = config.max_inodes;
2518 sbinfo->free_inodes = config.max_inodes - inodes;
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07002519
Greg Thelen5f001102013-02-22 16:36:01 -08002520 /*
2521 * Preserve previous mempolicy unless mpol remount option was specified.
2522 */
2523 if (config.mpol) {
2524 mpol_put(sbinfo->mpol);
2525 sbinfo->mpol = config.mpol; /* transfers initial ref */
2526 }
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002527out:
2528 spin_unlock(&sbinfo->stat_lock);
2529 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002530}
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002531
Al Viro34c80b12011-12-08 21:32:45 -05002532static int shmem_show_options(struct seq_file *seq, struct dentry *root)
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002533{
Al Viro34c80b12011-12-08 21:32:45 -05002534 struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002535
2536 if (sbinfo->max_blocks != shmem_default_max_blocks())
2537 seq_printf(seq, ",size=%luk",
2538 sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10));
2539 if (sbinfo->max_inodes != shmem_default_max_inodes())
2540 seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
2541 if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
Al Viro09208d12011-07-26 03:15:03 -04002542 seq_printf(seq, ",mode=%03ho", sbinfo->mode);
Eric W. Biederman8751e032012-02-07 16:46:12 -08002543 if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
2544 seq_printf(seq, ",uid=%u",
2545 from_kuid_munged(&init_user_ns, sbinfo->uid));
2546 if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
2547 seq_printf(seq, ",gid=%u",
2548 from_kgid_munged(&init_user_ns, sbinfo->gid));
Lee Schermerhorn71fe8042008-04-28 02:13:26 -07002549 shmem_show_mpol(seq, sbinfo->mpol);
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002550 return 0;
2551}
2552#endif /* CONFIG_TMPFS */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002553
2554static void shmem_put_super(struct super_block *sb)
2555{
Hugh Dickins602586a2010-08-17 15:23:56 -07002556 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
2557
2558 percpu_counter_destroy(&sbinfo->used_blocks);
Greg Thelen49cd0a52013-02-22 16:36:02 -08002559 mpol_put(sbinfo->mpol);
Hugh Dickins602586a2010-08-17 15:23:56 -07002560 kfree(sbinfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002561 sb->s_fs_info = NULL;
2562}
2563
Kay Sievers2b2af542009-04-30 15:23:42 +02002564int shmem_fill_super(struct super_block *sb, void *data, int silent)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002565{
2566 struct inode *inode;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002567 struct shmem_sb_info *sbinfo;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002568 int err = -ENOMEM;
2569
2570 /* Round up to L1_CACHE_BYTES to resist false sharing */
Pekka Enberg425fbf02009-09-21 17:03:50 -07002571 sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info),
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002572 L1_CACHE_BYTES), GFP_KERNEL);
2573 if (!sbinfo)
2574 return -ENOMEM;
2575
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002576 sbinfo->mode = S_IRWXUGO | S_ISVTX;
David Howells76aac0e2008-11-14 10:39:12 +11002577 sbinfo->uid = current_fsuid();
2578 sbinfo->gid = current_fsgid();
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002579 sb->s_fs_info = sbinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002580
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002581#ifdef CONFIG_TMPFS
Linus Torvalds1da177e2005-04-16 15:20:36 -07002582 /*
2583 * Per default we only allow half of the physical ram per
2584 * tmpfs instance, limiting inodes to one per page of lowmem;
2585 * but the internal instance is left unlimited.
2586 */
2587 if (!(sb->s_flags & MS_NOUSER)) {
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002588 sbinfo->max_blocks = shmem_default_max_blocks();
2589 sbinfo->max_inodes = shmem_default_max_inodes();
2590 if (shmem_parse_options(data, sbinfo, false)) {
2591 err = -EINVAL;
2592 goto failed;
2593 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002594 }
David M. Grimes91828a42006-10-17 00:09:45 -07002595 sb->s_export_op = &shmem_export_ops;
Hugh Dickins2f6e38f2012-05-29 15:06:38 -07002596 sb->s_flags |= MS_NOSEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002597#else
2598 sb->s_flags |= MS_NOUSER;
2599#endif
2600
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002601 spin_lock_init(&sbinfo->stat_lock);
Hugh Dickins602586a2010-08-17 15:23:56 -07002602 if (percpu_counter_init(&sbinfo->used_blocks, 0))
2603 goto failed;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002604 sbinfo->free_inodes = sbinfo->max_inodes;
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002605
Hugh Dickins285b2c42011-08-03 16:21:20 -07002606 sb->s_maxbytes = MAX_LFS_FILESIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002607 sb->s_blocksize = PAGE_CACHE_SIZE;
2608 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2609 sb->s_magic = TMPFS_MAGIC;
2610 sb->s_op = &shmem_ops;
Robin H. Johnsoncfd95a92006-06-12 21:50:25 +01002611 sb->s_time_gran = 1;
Eric Parisb09e0fa2011-05-24 17:12:39 -07002612#ifdef CONFIG_TMPFS_XATTR
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002613 sb->s_xattr = shmem_xattr_handlers;
Eric Parisb09e0fa2011-05-24 17:12:39 -07002614#endif
2615#ifdef CONFIG_TMPFS_POSIX_ACL
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002616 sb->s_flags |= MS_POSIXACL;
2617#endif
Hugh Dickins0edd73b2005-06-21 17:15:04 -07002618
Dmitry Monakhov454abaf2010-03-04 17:32:18 +03002619 inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002620 if (!inode)
2621 goto failed;
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002622 inode->i_uid = sbinfo->uid;
2623 inode->i_gid = sbinfo->gid;
Al Viro318ceed2012-02-12 22:08:01 -05002624 sb->s_root = d_make_root(inode);
2625 if (!sb->s_root)
Al Viro48fde702012-01-08 22:15:13 -05002626 goto failed;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002627 return 0;
2628
Linus Torvalds1da177e2005-04-16 15:20:36 -07002629failed:
2630 shmem_put_super(sb);
2631 return err;
2632}
2633
Pekka Enbergfcc234f2006-03-22 00:08:13 -08002634static struct kmem_cache *shmem_inode_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002635
2636static struct inode *shmem_alloc_inode(struct super_block *sb)
2637{
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002638 struct shmem_inode_info *info;
2639 info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
2640 if (!info)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002641 return NULL;
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002642 return &info->vfs_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002643}
2644
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002645static void shmem_destroy_callback(struct rcu_head *head)
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +11002646{
2647 struct inode *inode = container_of(head, struct inode, i_rcu);
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +11002648 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
2649}
2650
Linus Torvalds1da177e2005-04-16 15:20:36 -07002651static void shmem_destroy_inode(struct inode *inode)
2652{
Al Viro09208d12011-07-26 03:15:03 -04002653 if (S_ISREG(inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002654 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002655 call_rcu(&inode->i_rcu, shmem_destroy_callback);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002656}
2657
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002658static void shmem_init_inode(void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002659{
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002660 struct shmem_inode_info *info = foo;
2661 inode_init_once(&info->vfs_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002662}
2663
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002664static int shmem_init_inodecache(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002665{
2666 shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
2667 sizeof(struct shmem_inode_info),
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002668 0, SLAB_PANIC, shmem_init_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002669 return 0;
2670}
2671
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002672static void shmem_destroy_inodecache(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002673{
Alexey Dobriyan1a1d92c2006-09-27 01:49:40 -07002674 kmem_cache_destroy(shmem_inode_cachep);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002675}
2676
Christoph Hellwigf5e54d62006-06-28 04:26:44 -07002677static const struct address_space_operations shmem_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002678 .writepage = shmem_writepage,
Ken Chen76719322007-02-10 01:43:15 -08002679 .set_page_dirty = __set_page_dirty_no_writeback,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680#ifdef CONFIG_TMPFS
Nick Piggin800d15a2007-10-16 01:25:03 -07002681 .write_begin = shmem_write_begin,
2682 .write_end = shmem_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002683#endif
Lee Schermerhorn304dbdb2006-04-22 02:35:48 -07002684 .migratepage = migrate_page,
Andi Kleenaa261f52009-09-16 11:50:16 +02002685 .error_remove_page = generic_error_remove_page,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002686};
2687
Helge Deller15ad7cd2006-12-06 20:40:36 -08002688static const struct file_operations shmem_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002689 .mmap = shmem_mmap,
2690#ifdef CONFIG_TMPFS
Hugh Dickins220f2ac2012-12-12 13:52:21 -08002691 .llseek = shmem_file_llseek,
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07002692 .read = do_sync_read,
Hugh Dickins5402b972008-02-04 22:28:44 -08002693 .write = do_sync_write,
Hugh Dickinsbcd78e42008-07-23 21:27:35 -07002694 .aio_read = shmem_file_aio_read,
Hugh Dickins5402b972008-02-04 22:28:44 -08002695 .aio_write = generic_file_aio_write,
Christoph Hellwig1b061d92010-05-26 17:53:41 +02002696 .fsync = noop_fsync,
Hugh Dickins708e3502011-07-25 17:12:32 -07002697 .splice_read = shmem_file_splice_read,
Hugh Dickinsae9764162007-06-04 10:00:39 +02002698 .splice_write = generic_file_splice_write,
Hugh Dickins83e4fa92012-05-29 15:06:40 -07002699 .fallocate = shmem_fallocate,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002700#endif
2701};
2702
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002703static const struct inode_operations shmem_inode_operations = {
Hugh Dickins94c1e622011-06-27 16:18:03 -07002704 .setattr = shmem_setattr,
Eric Parisb09e0fa2011-05-24 17:12:39 -07002705#ifdef CONFIG_TMPFS_XATTR
2706 .setxattr = shmem_setxattr,
2707 .getxattr = shmem_getxattr,
2708 .listxattr = shmem_listxattr,
2709 .removexattr = shmem_removexattr,
2710#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002711};
2712
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002713static const struct inode_operations shmem_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002714#ifdef CONFIG_TMPFS
2715 .create = shmem_create,
2716 .lookup = simple_lookup,
2717 .link = shmem_link,
2718 .unlink = shmem_unlink,
2719 .symlink = shmem_symlink,
2720 .mkdir = shmem_mkdir,
2721 .rmdir = shmem_rmdir,
2722 .mknod = shmem_mknod,
2723 .rename = shmem_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002724#endif
Eric Parisb09e0fa2011-05-24 17:12:39 -07002725#ifdef CONFIG_TMPFS_XATTR
2726 .setxattr = shmem_setxattr,
2727 .getxattr = shmem_getxattr,
2728 .listxattr = shmem_listxattr,
2729 .removexattr = shmem_removexattr,
2730#endif
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002731#ifdef CONFIG_TMPFS_POSIX_ACL
Hugh Dickins94c1e622011-06-27 16:18:03 -07002732 .setattr = shmem_setattr,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002733#endif
2734};
2735
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002736static const struct inode_operations shmem_special_inode_operations = {
Eric Parisb09e0fa2011-05-24 17:12:39 -07002737#ifdef CONFIG_TMPFS_XATTR
2738 .setxattr = shmem_setxattr,
2739 .getxattr = shmem_getxattr,
2740 .listxattr = shmem_listxattr,
2741 .removexattr = shmem_removexattr,
2742#endif
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002743#ifdef CONFIG_TMPFS_POSIX_ACL
Hugh Dickins94c1e622011-06-27 16:18:03 -07002744 .setattr = shmem_setattr,
Andreas Gruenbacher39f02472006-09-29 02:01:35 -07002745#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002746};
2747
Hugh Dickins759b9772007-03-05 00:30:28 -08002748static const struct super_operations shmem_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002749 .alloc_inode = shmem_alloc_inode,
2750 .destroy_inode = shmem_destroy_inode,
2751#ifdef CONFIG_TMPFS
2752 .statfs = shmem_statfs,
2753 .remount_fs = shmem_remount_fs,
akpm@linux-foundation.org680d7942008-02-08 04:21:48 -08002754 .show_options = shmem_show_options,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002755#endif
Al Viro1f895f72010-06-05 19:10:41 -04002756 .evict_inode = shmem_evict_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002757 .drop_inode = generic_delete_inode,
2758 .put_super = shmem_put_super,
2759};
2760
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +04002761static const struct vm_operations_struct shmem_vm_ops = {
Nick Piggin54cb8822007-07-19 01:46:59 -07002762 .fault = shmem_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002763#ifdef CONFIG_NUMA
2764 .set_policy = shmem_set_policy,
2765 .get_policy = shmem_get_policy,
2766#endif
Konstantin Khlebnikov0b173bc2012-10-08 16:28:46 -07002767 .remap_pages = generic_file_remap_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002768};
2769
Al Viro3c26ff62010-07-25 11:46:36 +04002770static struct dentry *shmem_mount(struct file_system_type *fs_type,
2771 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002772{
Al Viro3c26ff62010-07-25 11:46:36 +04002773 return mount_nodev(fs_type, flags, data, shmem_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002774}
2775
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002776static struct file_system_type shmem_fs_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002777 .owner = THIS_MODULE,
2778 .name = "tmpfs",
Al Viro3c26ff62010-07-25 11:46:36 +04002779 .mount = shmem_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002780 .kill_sb = kill_litter_super,
Eric W. Biederman2b8576c2013-01-25 16:32:10 -08002781 .fs_flags = FS_USERNS_MOUNT,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002782};
Linus Torvalds1da177e2005-04-16 15:20:36 -07002783
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002784int __init shmem_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002785{
2786 int error;
2787
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -07002788 error = bdi_init(&shmem_backing_dev_info);
2789 if (error)
2790 goto out4;
2791
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002792 error = shmem_init_inodecache();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002793 if (error)
2794 goto out3;
2795
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002796 error = register_filesystem(&shmem_fs_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002797 if (error) {
2798 printk(KERN_ERR "Could not register tmpfs\n");
2799 goto out2;
2800 }
Greg Kroah-Hartman95dc1122005-06-20 21:15:16 -07002801
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002802 shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER,
2803 shmem_fs_type.name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002804 if (IS_ERR(shm_mnt)) {
2805 error = PTR_ERR(shm_mnt);
2806 printk(KERN_ERR "Could not kern_mount tmpfs\n");
2807 goto out1;
2808 }
2809 return 0;
2810
2811out1:
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002812 unregister_filesystem(&shmem_fs_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002813out2:
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002814 shmem_destroy_inodecache();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002815out3:
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -07002816 bdi_destroy(&shmem_backing_dev_info);
2817out4:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002818 shm_mnt = ERR_PTR(error);
2819 return error;
2820}
Matt Mackall853ac432009-01-06 14:40:20 -08002821
2822#else /* !CONFIG_SHMEM */
2823
2824/*
2825 * tiny-shmem: simple shmemfs and tmpfs using ramfs code
2826 *
2827 * This is intended for small system where the benefits of the full
2828 * shmem code (swap-backed and resource-limited) are outweighed by
2829 * their complexity. On systems without swap this code should be
2830 * effectively equivalent, but much lighter weight.
2831 */
2832
2833#include <linux/ramfs.h>
2834
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002835static struct file_system_type shmem_fs_type = {
Matt Mackall853ac432009-01-06 14:40:20 -08002836 .name = "tmpfs",
Al Viro3c26ff62010-07-25 11:46:36 +04002837 .mount = ramfs_mount,
Matt Mackall853ac432009-01-06 14:40:20 -08002838 .kill_sb = kill_litter_super,
Eric W. Biederman2b8576c2013-01-25 16:32:10 -08002839 .fs_flags = FS_USERNS_MOUNT,
Matt Mackall853ac432009-01-06 14:40:20 -08002840};
2841
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002842int __init shmem_init(void)
Matt Mackall853ac432009-01-06 14:40:20 -08002843{
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002844 BUG_ON(register_filesystem(&shmem_fs_type) != 0);
Matt Mackall853ac432009-01-06 14:40:20 -08002845
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002846 shm_mnt = kern_mount(&shmem_fs_type);
Matt Mackall853ac432009-01-06 14:40:20 -08002847 BUG_ON(IS_ERR(shm_mnt));
2848
2849 return 0;
2850}
2851
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002852int shmem_unuse(swp_entry_t swap, struct page *page)
Matt Mackall853ac432009-01-06 14:40:20 -08002853{
2854 return 0;
2855}
2856
Hugh Dickins3f96b792009-09-21 17:03:37 -07002857int shmem_lock(struct file *file, int lock, struct user_struct *user)
2858{
2859 return 0;
2860}
2861
Hugh Dickins24513262012-01-20 14:34:21 -08002862void shmem_unlock_mapping(struct address_space *mapping)
2863{
2864}
2865
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002866void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
Hugh Dickins94c1e622011-06-27 16:18:03 -07002867{
Hugh Dickins41ffe5d2011-08-03 16:21:21 -07002868 truncate_inode_pages_range(inode->i_mapping, lstart, lend);
Hugh Dickins94c1e622011-06-27 16:18:03 -07002869}
2870EXPORT_SYMBOL_GPL(shmem_truncate_range);
2871
Hugh Dickins0b0a0802009-02-24 20:51:52 +00002872#define shmem_vm_ops generic_file_vm_ops
2873#define shmem_file_operations ramfs_file_operations
Dmitry Monakhov454abaf2010-03-04 17:32:18 +03002874#define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
Hugh Dickins0b0a0802009-02-24 20:51:52 +00002875#define shmem_acct_size(flags, size) 0
2876#define shmem_unacct_size(flags, size) do {} while (0)
Matt Mackall853ac432009-01-06 14:40:20 -08002877
2878#endif /* CONFIG_SHMEM */
2879
2880/* common code */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002881
Al Viro34515382013-02-14 22:38:02 -05002882static char *shmem_dname(struct dentry *dentry, char *buffer, int buflen)
2883{
2884 return dynamic_dname(dentry, buffer, buflen, "/%s (deleted)",
2885 dentry->d_name.name);
2886}
2887
2888static struct dentry_operations anon_ops = {
2889 .d_dname = shmem_dname
2890};
2891
Randy Dunlap46711812008-03-19 17:00:41 -07002892/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002893 * shmem_file_setup - get an unlinked file living in tmpfs
Linus Torvalds1da177e2005-04-16 15:20:36 -07002894 * @name: name for dentry (to be seen in /proc/<pid>/maps
2895 * @size: size to be set for the file
Hugh Dickins0b0a0802009-02-24 20:51:52 +00002896 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
Linus Torvalds1da177e2005-04-16 15:20:36 -07002897 */
Sergei Trofimovich168f5ac2009-06-16 15:33:02 -07002898struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002899{
Al Viro6b4d0b22013-02-14 21:37:26 -05002900 struct file *res;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002901 struct inode *inode;
Al Viro2c48b9c2009-08-09 00:52:35 +04002902 struct path path;
Al Viro34515382013-02-14 22:38:02 -05002903 struct super_block *sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002904 struct qstr this;
2905
2906 if (IS_ERR(shm_mnt))
Al Viro6b4d0b22013-02-14 21:37:26 -05002907 return ERR_CAST(shm_mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002908
Hugh Dickins285b2c42011-08-03 16:21:20 -07002909 if (size < 0 || size > MAX_LFS_FILESIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002910 return ERR_PTR(-EINVAL);
2911
2912 if (shmem_acct_size(flags, size))
2913 return ERR_PTR(-ENOMEM);
2914
Al Viro6b4d0b22013-02-14 21:37:26 -05002915 res = ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002916 this.name = name;
2917 this.len = strlen(name);
2918 this.hash = 0; /* will go */
Al Viro34515382013-02-14 22:38:02 -05002919 sb = shm_mnt->mnt_sb;
2920 path.dentry = d_alloc_pseudo(sb, &this);
Al Viro2c48b9c2009-08-09 00:52:35 +04002921 if (!path.dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002922 goto put_memory;
Al Viro34515382013-02-14 22:38:02 -05002923 d_set_d_op(path.dentry, &anon_ops);
Al Viro2c48b9c2009-08-09 00:52:35 +04002924 path.mnt = mntget(shm_mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002925
Al Viro6b4d0b22013-02-14 21:37:26 -05002926 res = ERR_PTR(-ENOSPC);
Al Viro34515382013-02-14 22:38:02 -05002927 inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002928 if (!inode)
Al Viro4b42af82009-08-05 18:25:56 +04002929 goto put_dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002930
Al Viro2c48b9c2009-08-09 00:52:35 +04002931 d_instantiate(path.dentry, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002932 inode->i_size = size;
Miklos Szeredi6d6b77f2011-10-28 14:13:28 +02002933 clear_nlink(inode); /* It is unlinked */
Matt Mackall853ac432009-01-06 14:40:20 -08002934#ifndef CONFIG_MMU
Al Viro26567cd2013-03-01 20:22:53 -05002935 res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
2936 if (IS_ERR(res))
Al Viro4b42af82009-08-05 18:25:56 +04002937 goto put_dentry;
Matt Mackall853ac432009-01-06 14:40:20 -08002938#endif
Al Viro4b42af82009-08-05 18:25:56 +04002939
Al Viro6b4d0b22013-02-14 21:37:26 -05002940 res = alloc_file(&path, FMODE_WRITE | FMODE_READ,
Al Viro4b42af82009-08-05 18:25:56 +04002941 &shmem_file_operations);
Al Viro6b4d0b22013-02-14 21:37:26 -05002942 if (IS_ERR(res))
Al Viro4b42af82009-08-05 18:25:56 +04002943 goto put_dentry;
2944
Al Viro6b4d0b22013-02-14 21:37:26 -05002945 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002946
Linus Torvalds1da177e2005-04-16 15:20:36 -07002947put_dentry:
Al Viro2c48b9c2009-08-09 00:52:35 +04002948 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002949put_memory:
2950 shmem_unacct_size(flags, size);
Al Viro6b4d0b22013-02-14 21:37:26 -05002951 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002952}
Keith Packard395e0dd2008-06-20 00:08:06 -07002953EXPORT_SYMBOL_GPL(shmem_file_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002954
Randy Dunlap46711812008-03-19 17:00:41 -07002955/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002956 * shmem_zero_setup - setup a shared anonymous mapping
Linus Torvalds1da177e2005-04-16 15:20:36 -07002957 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2958 */
2959int shmem_zero_setup(struct vm_area_struct *vma)
2960{
2961 struct file *file;
2962 loff_t size = vma->vm_end - vma->vm_start;
2963
2964 file = shmem_file_setup("dev/zero", size, vma->vm_flags);
2965 if (IS_ERR(file))
2966 return PTR_ERR(file);
2967
2968 if (vma->vm_file)
2969 fput(vma->vm_file);
2970 vma->vm_file = file;
2971 vma->vm_ops = &shmem_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002972 return 0;
2973}
Hugh Dickinsd9d90e52011-06-27 16:18:04 -07002974
2975/**
2976 * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
2977 * @mapping: the page's address_space
2978 * @index: the page index
2979 * @gfp: the page allocator flags to use if allocating
2980 *
2981 * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
2982 * with any new page allocations done using the specified allocation flags.
2983 * But read_cache_page_gfp() uses the ->readpage() method: which does not
2984 * suit tmpfs, since it may have pages in swapcache, and needs to find those
2985 * for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
2986 *
Hugh Dickins68da9f02011-07-25 17:12:34 -07002987 * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
2988 * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
Hugh Dickinsd9d90e52011-06-27 16:18:04 -07002989 */
2990struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
2991 pgoff_t index, gfp_t gfp)
2992{
Hugh Dickins68da9f02011-07-25 17:12:34 -07002993#ifdef CONFIG_SHMEM
2994 struct inode *inode = mapping->host;
Hugh Dickins9276aad2011-07-25 17:12:34 -07002995 struct page *page;
Hugh Dickins68da9f02011-07-25 17:12:34 -07002996 int error;
2997
2998 BUG_ON(mapping->a_ops != &shmem_aops);
2999 error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL);
3000 if (error)
3001 page = ERR_PTR(error);
3002 else
3003 unlock_page(page);
3004 return page;
3005#else
3006 /*
3007 * The tiny !SHMEM case uses ramfs without swap
3008 */
Hugh Dickinsd9d90e52011-06-27 16:18:04 -07003009 return read_cache_page_gfp(mapping, index, gfp);
Hugh Dickins68da9f02011-07-25 17:12:34 -07003010#endif
Hugh Dickinsd9d90e52011-06-27 16:18:04 -07003011}
3012EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp);