Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
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. | |
0edd73b3 HD |
9 | * Copyright (C) 2002-2005 Hugh Dickins. |
10 | * Copyright (C) 2002-2005 VERITAS Software Corporation. | |
1da177e4 LT |
11 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
12 | * | |
13 | * Extended attribute support for tmpfs: | |
14 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
15 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
16 | * | |
853ac43a MM |
17 | * tiny-shmem: |
18 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
19 | * | |
1da177e4 LT |
20 | * This file is released under the GPL. |
21 | */ | |
22 | ||
853ac43a MM |
23 | #include <linux/fs.h> |
24 | #include <linux/init.h> | |
25 | #include <linux/vfs.h> | |
26 | #include <linux/mount.h> | |
caefba17 | 27 | #include <linux/pagemap.h> |
853ac43a MM |
28 | #include <linux/file.h> |
29 | #include <linux/mm.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/swap.h> | |
32 | ||
33 | static struct vfsmount *shm_mnt; | |
34 | ||
35 | #ifdef CONFIG_SHMEM | |
1da177e4 LT |
36 | /* |
37 | * This virtual memory filesystem is heavily based on the ramfs. It | |
38 | * extends ramfs by the ability to use swap and honor resource limits | |
39 | * which makes it a completely usable filesystem. | |
40 | */ | |
41 | ||
39f0247d | 42 | #include <linux/xattr.h> |
a5694255 | 43 | #include <linux/exportfs.h> |
1c7c474c | 44 | #include <linux/posix_acl.h> |
39f0247d | 45 | #include <linux/generic_acl.h> |
1da177e4 | 46 | #include <linux/mman.h> |
1da177e4 LT |
47 | #include <linux/string.h> |
48 | #include <linux/slab.h> | |
49 | #include <linux/backing-dev.h> | |
50 | #include <linux/shmem_fs.h> | |
1da177e4 | 51 | #include <linux/writeback.h> |
1da177e4 | 52 | #include <linux/blkdev.h> |
bda97eab | 53 | #include <linux/pagevec.h> |
41ffe5d5 | 54 | #include <linux/percpu_counter.h> |
708e3508 | 55 | #include <linux/splice.h> |
1da177e4 LT |
56 | #include <linux/security.h> |
57 | #include <linux/swapops.h> | |
58 | #include <linux/mempolicy.h> | |
59 | #include <linux/namei.h> | |
b00dc3ad | 60 | #include <linux/ctype.h> |
304dbdb7 | 61 | #include <linux/migrate.h> |
c1f60a5a | 62 | #include <linux/highmem.h> |
680d794b | 63 | #include <linux/seq_file.h> |
92562927 | 64 | #include <linux/magic.h> |
304dbdb7 | 65 | |
1da177e4 | 66 | #include <asm/uaccess.h> |
1da177e4 LT |
67 | #include <asm/pgtable.h> |
68 | ||
caefba17 | 69 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
1da177e4 LT |
70 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
71 | ||
1da177e4 LT |
72 | /* Pretend that each entry is of this size in directory's i_size */ |
73 | #define BOGO_DIRENT_SIZE 20 | |
74 | ||
b09e0fa4 EP |
75 | struct shmem_xattr { |
76 | struct list_head list; /* anchored by shmem_inode_info->xattr_list */ | |
77 | char *name; /* xattr name */ | |
78 | size_t size; | |
79 | char value[0]; | |
80 | }; | |
81 | ||
285b2c4f | 82 | /* Flag allocation requirements to shmem_getpage */ |
1da177e4 | 83 | enum sgp_type { |
1da177e4 LT |
84 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
85 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 86 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
87 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
88 | }; | |
89 | ||
b76db735 | 90 | #ifdef CONFIG_TMPFS |
680d794b | 91 | static unsigned long shmem_default_max_blocks(void) |
92 | { | |
93 | return totalram_pages / 2; | |
94 | } | |
95 | ||
96 | static unsigned long shmem_default_max_inodes(void) | |
97 | { | |
98 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
99 | } | |
b76db735 | 100 | #endif |
680d794b | 101 | |
68da9f05 HD |
102 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
103 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); | |
104 | ||
105 | static inline int shmem_getpage(struct inode *inode, pgoff_t index, | |
106 | struct page **pagep, enum sgp_type sgp, int *fault_type) | |
107 | { | |
108 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
109 | mapping_gfp_mask(inode->i_mapping), fault_type); | |
110 | } | |
1da177e4 | 111 | |
1da177e4 LT |
112 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
113 | { | |
114 | return sb->s_fs_info; | |
115 | } | |
116 | ||
117 | /* | |
118 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
119 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
120 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
121 | * consistent with the pre-accounting of private mappings ... | |
122 | */ | |
123 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
124 | { | |
0b0a0806 HD |
125 | return (flags & VM_NORESERVE) ? |
126 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
127 | } |
128 | ||
129 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
130 | { | |
0b0a0806 | 131 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
132 | vm_unacct_memory(VM_ACCT(size)); |
133 | } | |
134 | ||
135 | /* | |
136 | * ... whereas tmpfs objects are accounted incrementally as | |
137 | * pages are allocated, in order to allow huge sparse files. | |
138 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
139 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
140 | */ | |
141 | static inline int shmem_acct_block(unsigned long flags) | |
142 | { | |
0b0a0806 HD |
143 | return (flags & VM_NORESERVE) ? |
144 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
145 | } |
146 | ||
147 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
148 | { | |
0b0a0806 | 149 | if (flags & VM_NORESERVE) |
1da177e4 LT |
150 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
151 | } | |
152 | ||
759b9775 | 153 | static const struct super_operations shmem_ops; |
f5e54d6e | 154 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 155 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
156 | static const struct inode_operations shmem_inode_operations; |
157 | static const struct inode_operations shmem_dir_inode_operations; | |
158 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 159 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 160 | |
6c231b7b | 161 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 162 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 163 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
164 | }; |
165 | ||
166 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 167 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 LT |
168 | |
169 | static void shmem_free_blocks(struct inode *inode, long pages) | |
170 | { | |
171 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 172 | if (sbinfo->max_blocks) { |
7e496299 | 173 | percpu_counter_add(&sbinfo->used_blocks, -pages); |
1da177e4 | 174 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; |
1da177e4 LT |
175 | } |
176 | } | |
177 | ||
5b04c689 PE |
178 | static int shmem_reserve_inode(struct super_block *sb) |
179 | { | |
180 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
181 | if (sbinfo->max_inodes) { | |
182 | spin_lock(&sbinfo->stat_lock); | |
183 | if (!sbinfo->free_inodes) { | |
184 | spin_unlock(&sbinfo->stat_lock); | |
185 | return -ENOSPC; | |
186 | } | |
187 | sbinfo->free_inodes--; | |
188 | spin_unlock(&sbinfo->stat_lock); | |
189 | } | |
190 | return 0; | |
191 | } | |
192 | ||
193 | static void shmem_free_inode(struct super_block *sb) | |
194 | { | |
195 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
196 | if (sbinfo->max_inodes) { | |
197 | spin_lock(&sbinfo->stat_lock); | |
198 | sbinfo->free_inodes++; | |
199 | spin_unlock(&sbinfo->stat_lock); | |
200 | } | |
201 | } | |
202 | ||
46711810 | 203 | /** |
41ffe5d5 | 204 | * shmem_recalc_inode - recalculate the block usage of an inode |
1da177e4 LT |
205 | * @inode: inode to recalc |
206 | * | |
207 | * We have to calculate the free blocks since the mm can drop | |
208 | * undirtied hole pages behind our back. | |
209 | * | |
210 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
211 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
212 | * | |
213 | * It has to be called with the spinlock held. | |
214 | */ | |
215 | static void shmem_recalc_inode(struct inode *inode) | |
216 | { | |
217 | struct shmem_inode_info *info = SHMEM_I(inode); | |
218 | long freed; | |
219 | ||
220 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
221 | if (freed > 0) { | |
222 | info->alloced -= freed; | |
223 | shmem_unacct_blocks(info->flags, freed); | |
224 | shmem_free_blocks(inode, freed); | |
225 | } | |
226 | } | |
227 | ||
285b2c4f HD |
228 | static void shmem_put_swap(struct shmem_inode_info *info, pgoff_t index, |
229 | swp_entry_t swap) | |
1da177e4 | 230 | { |
285b2c4f HD |
231 | if (index < SHMEM_NR_DIRECT) |
232 | info->i_direct[index] = swap; | |
1da177e4 LT |
233 | } |
234 | ||
285b2c4f | 235 | static swp_entry_t shmem_get_swap(struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 236 | { |
285b2c4f HD |
237 | return (index < SHMEM_NR_DIRECT) ? |
238 | info->i_direct[index] : (swp_entry_t){0}; | |
1da177e4 LT |
239 | } |
240 | ||
7a5d0fbb HD |
241 | /* |
242 | * Replace item expected in radix tree by a new item, while holding tree lock. | |
243 | */ | |
244 | static int shmem_radix_tree_replace(struct address_space *mapping, | |
245 | pgoff_t index, void *expected, void *replacement) | |
246 | { | |
247 | void **pslot; | |
248 | void *item = NULL; | |
249 | ||
250 | VM_BUG_ON(!expected); | |
251 | pslot = radix_tree_lookup_slot(&mapping->page_tree, index); | |
252 | if (pslot) | |
253 | item = radix_tree_deref_slot_protected(pslot, | |
254 | &mapping->tree_lock); | |
255 | if (item != expected) | |
256 | return -ENOENT; | |
257 | if (replacement) | |
258 | radix_tree_replace_slot(pslot, replacement); | |
259 | else | |
260 | radix_tree_delete(&mapping->page_tree, index); | |
261 | return 0; | |
262 | } | |
263 | ||
46f65ec1 HD |
264 | /* |
265 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
266 | */ | |
267 | static int shmem_add_to_page_cache(struct page *page, | |
268 | struct address_space *mapping, | |
269 | pgoff_t index, gfp_t gfp, void *expected) | |
270 | { | |
271 | int error; | |
272 | ||
273 | VM_BUG_ON(!PageLocked(page)); | |
274 | VM_BUG_ON(!PageSwapBacked(page)); | |
275 | ||
276 | error = mem_cgroup_cache_charge(page, current->mm, | |
277 | gfp & GFP_RECLAIM_MASK); | |
278 | if (error) | |
279 | goto out; | |
280 | if (!expected) | |
281 | error = radix_tree_preload(gfp & GFP_RECLAIM_MASK); | |
282 | if (!error) { | |
283 | page_cache_get(page); | |
284 | page->mapping = mapping; | |
285 | page->index = index; | |
286 | ||
287 | spin_lock_irq(&mapping->tree_lock); | |
288 | if (!expected) | |
289 | error = radix_tree_insert(&mapping->page_tree, | |
290 | index, page); | |
291 | else | |
292 | error = shmem_radix_tree_replace(mapping, index, | |
293 | expected, page); | |
294 | if (!error) { | |
295 | mapping->nrpages++; | |
296 | __inc_zone_page_state(page, NR_FILE_PAGES); | |
297 | __inc_zone_page_state(page, NR_SHMEM); | |
298 | spin_unlock_irq(&mapping->tree_lock); | |
299 | } else { | |
300 | page->mapping = NULL; | |
301 | spin_unlock_irq(&mapping->tree_lock); | |
302 | page_cache_release(page); | |
303 | } | |
304 | if (!expected) | |
305 | radix_tree_preload_end(); | |
306 | } | |
307 | if (error) | |
308 | mem_cgroup_uncharge_cache_page(page); | |
309 | out: | |
310 | return error; | |
311 | } | |
312 | ||
7a5d0fbb HD |
313 | /* |
314 | * Like find_get_pages, but collecting swap entries as well as pages. | |
315 | */ | |
316 | static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping, | |
317 | pgoff_t start, unsigned int nr_pages, | |
318 | struct page **pages, pgoff_t *indices) | |
319 | { | |
320 | unsigned int i; | |
321 | unsigned int ret; | |
322 | unsigned int nr_found; | |
323 | ||
324 | rcu_read_lock(); | |
325 | restart: | |
326 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, | |
327 | (void ***)pages, indices, start, nr_pages); | |
328 | ret = 0; | |
329 | for (i = 0; i < nr_found; i++) { | |
330 | struct page *page; | |
331 | repeat: | |
332 | page = radix_tree_deref_slot((void **)pages[i]); | |
333 | if (unlikely(!page)) | |
334 | continue; | |
335 | if (radix_tree_exception(page)) { | |
336 | if (radix_tree_exceptional_entry(page)) | |
337 | goto export; | |
338 | /* radix_tree_deref_retry(page) */ | |
339 | goto restart; | |
340 | } | |
341 | if (!page_cache_get_speculative(page)) | |
342 | goto repeat; | |
343 | ||
344 | /* Has the page moved? */ | |
345 | if (unlikely(page != *((void **)pages[i]))) { | |
346 | page_cache_release(page); | |
347 | goto repeat; | |
348 | } | |
349 | export: | |
350 | indices[ret] = indices[i]; | |
351 | pages[ret] = page; | |
352 | ret++; | |
353 | } | |
354 | if (unlikely(!ret && nr_found)) | |
355 | goto restart; | |
356 | rcu_read_unlock(); | |
357 | return ret; | |
358 | } | |
359 | ||
46f65ec1 HD |
360 | /* |
361 | * Lockless lookup of swap entry in radix tree, avoiding refcount on pages. | |
362 | */ | |
363 | static pgoff_t shmem_find_swap(struct address_space *mapping, void *radswap) | |
364 | { | |
365 | void **slots[PAGEVEC_SIZE]; | |
366 | pgoff_t indices[PAGEVEC_SIZE]; | |
367 | unsigned int nr_found; | |
368 | ||
369 | restart: | |
370 | nr_found = 1; | |
371 | indices[0] = -1; | |
372 | while (nr_found) { | |
373 | pgoff_t index = indices[nr_found - 1] + 1; | |
374 | unsigned int i; | |
375 | ||
376 | rcu_read_lock(); | |
377 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, | |
378 | slots, indices, index, PAGEVEC_SIZE); | |
379 | for (i = 0; i < nr_found; i++) { | |
380 | void *item = radix_tree_deref_slot(slots[i]); | |
381 | if (radix_tree_deref_retry(item)) { | |
382 | rcu_read_unlock(); | |
383 | goto restart; | |
384 | } | |
385 | if (item == radswap) { | |
386 | rcu_read_unlock(); | |
387 | return indices[i]; | |
388 | } | |
389 | } | |
390 | rcu_read_unlock(); | |
391 | cond_resched(); | |
392 | } | |
393 | return -1; | |
394 | } | |
395 | ||
7a5d0fbb HD |
396 | /* |
397 | * Remove swap entry from radix tree, free the swap and its page cache. | |
398 | */ | |
399 | static int shmem_free_swap(struct address_space *mapping, | |
400 | pgoff_t index, void *radswap) | |
401 | { | |
402 | int error; | |
403 | ||
404 | spin_lock_irq(&mapping->tree_lock); | |
405 | error = shmem_radix_tree_replace(mapping, index, radswap, NULL); | |
406 | spin_unlock_irq(&mapping->tree_lock); | |
407 | if (!error) | |
408 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
409 | return error; | |
410 | } | |
411 | ||
412 | /* | |
413 | * Pagevec may contain swap entries, so shuffle up pages before releasing. | |
414 | */ | |
415 | static void shmem_pagevec_release(struct pagevec *pvec) | |
416 | { | |
417 | int i, j; | |
418 | ||
419 | for (i = 0, j = 0; i < pagevec_count(pvec); i++) { | |
420 | struct page *page = pvec->pages[i]; | |
421 | if (!radix_tree_exceptional_entry(page)) | |
422 | pvec->pages[j++] = page; | |
423 | } | |
424 | pvec->nr = j; | |
425 | pagevec_release(pvec); | |
426 | } | |
427 | ||
428 | /* | |
429 | * Remove range of pages and swap entries from radix tree, and free them. | |
430 | */ | |
285b2c4f | 431 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
1da177e4 | 432 | { |
285b2c4f | 433 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 434 | struct shmem_inode_info *info = SHMEM_I(inode); |
285b2c4f | 435 | pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
bda97eab | 436 | unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); |
285b2c4f | 437 | pgoff_t end = (lend >> PAGE_CACHE_SHIFT); |
bda97eab | 438 | struct pagevec pvec; |
7a5d0fbb HD |
439 | pgoff_t indices[PAGEVEC_SIZE]; |
440 | long nr_swaps_freed = 0; | |
285b2c4f | 441 | pgoff_t index; |
bda97eab HD |
442 | int i; |
443 | ||
444 | BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); | |
445 | ||
446 | pagevec_init(&pvec, 0); | |
447 | index = start; | |
7a5d0fbb HD |
448 | while (index <= end) { |
449 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, | |
450 | min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, | |
451 | pvec.pages, indices); | |
452 | if (!pvec.nr) | |
453 | break; | |
bda97eab HD |
454 | mem_cgroup_uncharge_start(); |
455 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
456 | struct page *page = pvec.pages[i]; | |
457 | ||
7a5d0fbb | 458 | index = indices[i]; |
bda97eab HD |
459 | if (index > end) |
460 | break; | |
461 | ||
7a5d0fbb HD |
462 | if (radix_tree_exceptional_entry(page)) { |
463 | nr_swaps_freed += !shmem_free_swap(mapping, | |
464 | index, page); | |
bda97eab | 465 | continue; |
7a5d0fbb HD |
466 | } |
467 | ||
468 | if (!trylock_page(page)) | |
bda97eab | 469 | continue; |
7a5d0fbb HD |
470 | if (page->mapping == mapping) { |
471 | VM_BUG_ON(PageWriteback(page)); | |
472 | truncate_inode_page(mapping, page); | |
bda97eab | 473 | } |
bda97eab HD |
474 | unlock_page(page); |
475 | } | |
7a5d0fbb | 476 | shmem_pagevec_release(&pvec); |
bda97eab HD |
477 | mem_cgroup_uncharge_end(); |
478 | cond_resched(); | |
479 | index++; | |
480 | } | |
1da177e4 | 481 | |
bda97eab HD |
482 | if (partial) { |
483 | struct page *page = NULL; | |
484 | shmem_getpage(inode, start - 1, &page, SGP_READ, NULL); | |
485 | if (page) { | |
486 | zero_user_segment(page, partial, PAGE_CACHE_SIZE); | |
487 | set_page_dirty(page); | |
488 | unlock_page(page); | |
489 | page_cache_release(page); | |
490 | } | |
491 | } | |
492 | ||
493 | index = start; | |
494 | for ( ; ; ) { | |
495 | cond_resched(); | |
7a5d0fbb HD |
496 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, |
497 | min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, | |
498 | pvec.pages, indices); | |
499 | if (!pvec.nr) { | |
bda97eab HD |
500 | if (index == start) |
501 | break; | |
502 | index = start; | |
503 | continue; | |
504 | } | |
7a5d0fbb HD |
505 | if (index == start && indices[0] > end) { |
506 | shmem_pagevec_release(&pvec); | |
bda97eab HD |
507 | break; |
508 | } | |
509 | mem_cgroup_uncharge_start(); | |
510 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
511 | struct page *page = pvec.pages[i]; | |
512 | ||
7a5d0fbb | 513 | index = indices[i]; |
bda97eab HD |
514 | if (index > end) |
515 | break; | |
516 | ||
7a5d0fbb HD |
517 | if (radix_tree_exceptional_entry(page)) { |
518 | nr_swaps_freed += !shmem_free_swap(mapping, | |
519 | index, page); | |
520 | continue; | |
521 | } | |
522 | ||
bda97eab | 523 | lock_page(page); |
7a5d0fbb HD |
524 | if (page->mapping == mapping) { |
525 | VM_BUG_ON(PageWriteback(page)); | |
526 | truncate_inode_page(mapping, page); | |
527 | } | |
bda97eab HD |
528 | unlock_page(page); |
529 | } | |
7a5d0fbb | 530 | shmem_pagevec_release(&pvec); |
bda97eab HD |
531 | mem_cgroup_uncharge_end(); |
532 | index++; | |
533 | } | |
94c1e62d | 534 | |
1da177e4 | 535 | spin_lock(&info->lock); |
7a5d0fbb | 536 | info->swapped -= nr_swaps_freed; |
1da177e4 LT |
537 | shmem_recalc_inode(inode); |
538 | spin_unlock(&info->lock); | |
539 | ||
285b2c4f | 540 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1da177e4 | 541 | } |
94c1e62d | 542 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 543 | |
94c1e62d | 544 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 LT |
545 | { |
546 | struct inode *inode = dentry->d_inode; | |
1da177e4 LT |
547 | int error; |
548 | ||
db78b877 CH |
549 | error = inode_change_ok(inode, attr); |
550 | if (error) | |
551 | return error; | |
552 | ||
94c1e62d HD |
553 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
554 | loff_t oldsize = inode->i_size; | |
555 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 556 | |
94c1e62d HD |
557 | if (newsize != oldsize) { |
558 | i_size_write(inode, newsize); | |
559 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
560 | } | |
561 | if (newsize < oldsize) { | |
562 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
563 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
564 | shmem_truncate_range(inode, newsize, (loff_t)-1); | |
565 | /* unmap again to remove racily COWed private pages */ | |
566 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
567 | } | |
1da177e4 LT |
568 | } |
569 | ||
db78b877 | 570 | setattr_copy(inode, attr); |
39f0247d | 571 | #ifdef CONFIG_TMPFS_POSIX_ACL |
db78b877 | 572 | if (attr->ia_valid & ATTR_MODE) |
1c7c474c | 573 | error = generic_acl_chmod(inode); |
39f0247d | 574 | #endif |
1da177e4 LT |
575 | return error; |
576 | } | |
577 | ||
1f895f75 | 578 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 579 | { |
1da177e4 | 580 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 581 | struct shmem_xattr *xattr, *nxattr; |
1da177e4 | 582 | |
3889e6e7 | 583 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
584 | shmem_unacct_size(info->flags, inode->i_size); |
585 | inode->i_size = 0; | |
3889e6e7 | 586 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 587 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 588 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 589 | list_del_init(&info->swaplist); |
cb5f7b9a | 590 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
591 | } |
592 | } | |
b09e0fa4 EP |
593 | |
594 | list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { | |
595 | kfree(xattr->name); | |
596 | kfree(xattr); | |
597 | } | |
0edd73b3 | 598 | BUG_ON(inode->i_blocks); |
5b04c689 | 599 | shmem_free_inode(inode->i_sb); |
1f895f75 | 600 | end_writeback(inode); |
1da177e4 LT |
601 | } |
602 | ||
46f65ec1 HD |
603 | /* |
604 | * If swap found in inode, free it and move page from swapcache to filecache. | |
605 | */ | |
41ffe5d5 HD |
606 | static int shmem_unuse_inode(struct shmem_inode_info *info, |
607 | swp_entry_t swap, struct page *page) | |
1da177e4 | 608 | { |
285b2c4f | 609 | struct address_space *mapping = info->vfs_inode.i_mapping; |
46f65ec1 | 610 | void *radswap; |
41ffe5d5 | 611 | pgoff_t index; |
d9fe526a | 612 | int error; |
1da177e4 | 613 | |
46f65ec1 HD |
614 | radswap = swp_to_radix_entry(swap); |
615 | index = shmem_find_swap(mapping, radswap); | |
616 | if (index == -1) | |
285b2c4f | 617 | return 0; |
2e0e26c7 | 618 | |
1b1b32f2 HD |
619 | /* |
620 | * Move _head_ to start search for next from here. | |
1f895f75 | 621 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 | 622 | * mutex, and there's an instant in list_move_tail when info->swaplist |
285b2c4f | 623 | * would appear empty, if it were the only one on shmem_swaplist. |
1b1b32f2 HD |
624 | */ |
625 | if (shmem_swaplist.next != &info->swaplist) | |
626 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 627 | |
d13d1443 | 628 | /* |
778dd893 HD |
629 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
630 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
631 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 632 | */ |
46f65ec1 HD |
633 | error = shmem_add_to_page_cache(page, mapping, index, |
634 | GFP_NOWAIT, radswap); | |
778dd893 | 635 | /* which does mem_cgroup_uncharge_cache_page on error */ |
69029cd5 | 636 | |
48f170fb | 637 | if (error != -ENOMEM) { |
46f65ec1 HD |
638 | /* |
639 | * Truncation and eviction use free_swap_and_cache(), which | |
640 | * only does trylock page: if we raced, best clean up here. | |
641 | */ | |
73b1262f HD |
642 | delete_from_swap_cache(page); |
643 | set_page_dirty(page); | |
46f65ec1 HD |
644 | if (!error) { |
645 | spin_lock(&info->lock); | |
646 | info->swapped--; | |
647 | spin_unlock(&info->lock); | |
648 | swap_free(swap); | |
649 | } | |
2e0e26c7 | 650 | error = 1; /* not an error, but entry was found */ |
1da177e4 | 651 | } |
2e0e26c7 | 652 | return error; |
1da177e4 LT |
653 | } |
654 | ||
655 | /* | |
46f65ec1 | 656 | * Search through swapped inodes to find and replace swap by page. |
1da177e4 | 657 | */ |
41ffe5d5 | 658 | int shmem_unuse(swp_entry_t swap, struct page *page) |
1da177e4 | 659 | { |
41ffe5d5 | 660 | struct list_head *this, *next; |
1da177e4 LT |
661 | struct shmem_inode_info *info; |
662 | int found = 0; | |
778dd893 HD |
663 | int error; |
664 | ||
665 | /* | |
666 | * Charge page using GFP_KERNEL while we can wait, before taking | |
667 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
668 | * Charged back to the user (not to caller) when swap account is used. | |
46f65ec1 | 669 | * shmem_add_to_page_cache() will be called with GFP_NOWAIT. |
778dd893 HD |
670 | */ |
671 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
672 | if (error) | |
673 | goto out; | |
46f65ec1 | 674 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
1da177e4 | 675 | |
cb5f7b9a | 676 | mutex_lock(&shmem_swaplist_mutex); |
41ffe5d5 HD |
677 | list_for_each_safe(this, next, &shmem_swaplist) { |
678 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
285b2c4f HD |
679 | if (!info->swapped) { |
680 | spin_lock(&info->lock); | |
681 | if (!info->swapped) | |
682 | list_del_init(&info->swaplist); | |
683 | spin_unlock(&info->lock); | |
684 | } | |
685 | if (info->swapped) | |
41ffe5d5 | 686 | found = shmem_unuse_inode(info, swap, page); |
cb5f7b9a | 687 | cond_resched(); |
2e0e26c7 | 688 | if (found) |
778dd893 | 689 | break; |
1da177e4 | 690 | } |
cb5f7b9a | 691 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 | 692 | |
778dd893 HD |
693 | if (!found) |
694 | mem_cgroup_uncharge_cache_page(page); | |
695 | if (found < 0) | |
696 | error = found; | |
697 | out: | |
aaa46865 HD |
698 | unlock_page(page); |
699 | page_cache_release(page); | |
778dd893 | 700 | return error; |
1da177e4 LT |
701 | } |
702 | ||
703 | /* | |
704 | * Move the page from the page cache to the swap cache. | |
705 | */ | |
706 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
707 | { | |
708 | struct shmem_inode_info *info; | |
285b2c4f | 709 | swp_entry_t swap, oswap; |
1da177e4 | 710 | struct address_space *mapping; |
41ffe5d5 | 711 | pgoff_t index; |
1da177e4 LT |
712 | struct inode *inode; |
713 | ||
714 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
715 | mapping = page->mapping; |
716 | index = page->index; | |
717 | inode = mapping->host; | |
718 | info = SHMEM_I(inode); | |
719 | if (info->flags & VM_LOCKED) | |
720 | goto redirty; | |
d9fe526a | 721 | if (!total_swap_pages) |
1da177e4 LT |
722 | goto redirty; |
723 | ||
d9fe526a HD |
724 | /* |
725 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
726 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
48f170fb | 727 | * might use ->writepage of its underlying filesystem, in which case |
d9fe526a | 728 | * tmpfs should write out to swap only in response to memory pressure, |
48f170fb | 729 | * and not for the writeback threads or sync. |
d9fe526a | 730 | */ |
48f170fb HD |
731 | if (!wbc->for_reclaim) { |
732 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
733 | goto redirty; | |
734 | } | |
285b2c4f HD |
735 | |
736 | /* | |
7a5d0fbb HD |
737 | * Disable even the toy swapping implementation, while we convert |
738 | * functions one by one to having swap entries in the radix tree. | |
285b2c4f | 739 | */ |
7a5d0fbb | 740 | if (index < ULONG_MAX) |
285b2c4f HD |
741 | goto redirty; |
742 | ||
48f170fb HD |
743 | swap = get_swap_page(); |
744 | if (!swap.val) | |
745 | goto redirty; | |
d9fe526a | 746 | |
b1dea800 HD |
747 | /* |
748 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
749 | * if it's not already there. Do it now because we cannot take | |
750 | * mutex while holding spinlock, and must do so before the page | |
751 | * is moved to swap cache, when its pagelock no longer protects | |
752 | * the inode from eviction. But don't unlock the mutex until | |
753 | * we've taken the spinlock, because shmem_unuse_inode() will | |
754 | * prune a !swapped inode from the swaplist under both locks. | |
755 | */ | |
48f170fb HD |
756 | mutex_lock(&shmem_swaplist_mutex); |
757 | if (list_empty(&info->swaplist)) | |
758 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 759 | |
1da177e4 | 760 | spin_lock(&info->lock); |
48f170fb | 761 | mutex_unlock(&shmem_swaplist_mutex); |
b1dea800 | 762 | |
285b2c4f HD |
763 | oswap = shmem_get_swap(info, index); |
764 | if (oswap.val) { | |
48f170fb | 765 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ |
285b2c4f HD |
766 | free_swap_and_cache(oswap); |
767 | shmem_put_swap(info, index, (swp_entry_t){0}); | |
768 | info->swapped--; | |
d9fe526a HD |
769 | } |
770 | shmem_recalc_inode(inode); | |
1da177e4 | 771 | |
48f170fb | 772 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
4c73b1bc | 773 | delete_from_page_cache(page); |
285b2c4f HD |
774 | shmem_put_swap(info, index, swap); |
775 | info->swapped++; | |
aaa46865 | 776 | swap_shmem_alloc(swap); |
826267cf | 777 | spin_unlock(&info->lock); |
d9fe526a | 778 | BUG_ON(page_mapped(page)); |
9fab5619 | 779 | swap_writepage(page, wbc); |
1da177e4 LT |
780 | return 0; |
781 | } | |
782 | ||
1da177e4 | 783 | spin_unlock(&info->lock); |
cb4b86ba | 784 | swapcache_free(swap, NULL); |
1da177e4 LT |
785 | redirty: |
786 | set_page_dirty(page); | |
d9fe526a HD |
787 | if (wbc->for_reclaim) |
788 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
789 | unlock_page(page); | |
790 | return 0; | |
1da177e4 LT |
791 | } |
792 | ||
793 | #ifdef CONFIG_NUMA | |
680d794b | 794 | #ifdef CONFIG_TMPFS |
71fe804b | 795 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 796 | { |
095f1fc4 | 797 | char buffer[64]; |
680d794b | 798 | |
71fe804b | 799 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 800 | return; /* show nothing */ |
680d794b | 801 | |
71fe804b | 802 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
803 | |
804 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 805 | } |
71fe804b LS |
806 | |
807 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
808 | { | |
809 | struct mempolicy *mpol = NULL; | |
810 | if (sbinfo->mpol) { | |
811 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
812 | mpol = sbinfo->mpol; | |
813 | mpol_get(mpol); | |
814 | spin_unlock(&sbinfo->stat_lock); | |
815 | } | |
816 | return mpol; | |
817 | } | |
680d794b | 818 | #endif /* CONFIG_TMPFS */ |
819 | ||
41ffe5d5 HD |
820 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
821 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 822 | { |
52cd3b07 | 823 | struct mempolicy mpol, *spol; |
1da177e4 LT |
824 | struct vm_area_struct pvma; |
825 | ||
52cd3b07 | 826 | spol = mpol_cond_copy(&mpol, |
41ffe5d5 | 827 | mpol_shared_policy_lookup(&info->policy, index)); |
52cd3b07 | 828 | |
1da177e4 | 829 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 830 | pvma.vm_start = 0; |
41ffe5d5 | 831 | pvma.vm_pgoff = index; |
c4cc6d07 | 832 | pvma.vm_ops = NULL; |
52cd3b07 | 833 | pvma.vm_policy = spol; |
41ffe5d5 | 834 | return swapin_readahead(swap, gfp, &pvma, 0); |
1da177e4 LT |
835 | } |
836 | ||
02098fea | 837 | static struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 838 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 LT |
839 | { |
840 | struct vm_area_struct pvma; | |
1da177e4 | 841 | |
c4cc6d07 HD |
842 | /* Create a pseudo vma that just contains the policy */ |
843 | pvma.vm_start = 0; | |
41ffe5d5 | 844 | pvma.vm_pgoff = index; |
c4cc6d07 | 845 | pvma.vm_ops = NULL; |
41ffe5d5 | 846 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
52cd3b07 LS |
847 | |
848 | /* | |
849 | * alloc_page_vma() will drop the shared policy reference | |
850 | */ | |
851 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 852 | } |
680d794b | 853 | #else /* !CONFIG_NUMA */ |
854 | #ifdef CONFIG_TMPFS | |
41ffe5d5 | 855 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 856 | { |
857 | } | |
858 | #endif /* CONFIG_TMPFS */ | |
859 | ||
41ffe5d5 HD |
860 | static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
861 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 862 | { |
41ffe5d5 | 863 | return swapin_readahead(swap, gfp, NULL, 0); |
1da177e4 LT |
864 | } |
865 | ||
02098fea | 866 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 867 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 868 | { |
e84e2e13 | 869 | return alloc_page(gfp); |
1da177e4 | 870 | } |
680d794b | 871 | #endif /* CONFIG_NUMA */ |
1da177e4 | 872 | |
71fe804b LS |
873 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
874 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
875 | { | |
876 | return NULL; | |
877 | } | |
878 | #endif | |
879 | ||
1da177e4 | 880 | /* |
68da9f05 | 881 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
882 | * |
883 | * If we allocate a new one we do not mark it dirty. That's up to the | |
884 | * vm. If we swap it in we mark it dirty since we also free the swap | |
885 | * entry since a page cannot live in both the swap and page cache | |
886 | */ | |
41ffe5d5 | 887 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
68da9f05 | 888 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) |
1da177e4 LT |
889 | { |
890 | struct address_space *mapping = inode->i_mapping; | |
891 | struct shmem_inode_info *info = SHMEM_I(inode); | |
892 | struct shmem_sb_info *sbinfo; | |
27ab7006 | 893 | struct page *page; |
ff36b801 | 894 | struct page *prealloc_page = NULL; |
1da177e4 LT |
895 | swp_entry_t swap; |
896 | int error; | |
897 | ||
41ffe5d5 | 898 | if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
1da177e4 | 899 | return -EFBIG; |
1da177e4 | 900 | repeat: |
41ffe5d5 | 901 | page = find_lock_page(mapping, index); |
27ab7006 | 902 | if (page) { |
b409f9fc | 903 | /* |
27ab7006 HD |
904 | * Once we can get the page lock, it must be uptodate: |
905 | * if there were an error in reading back from swap, | |
906 | * the page would not be inserted into the filecache. | |
b409f9fc | 907 | */ |
27ab7006 HD |
908 | BUG_ON(!PageUptodate(page)); |
909 | goto done; | |
910 | } | |
911 | ||
912 | /* | |
913 | * Try to preload while we can wait, to not make a habit of | |
914 | * draining atomic reserves; but don't latch on to this cpu. | |
915 | */ | |
916 | error = radix_tree_preload(gfp & GFP_RECLAIM_MASK); | |
917 | if (error) | |
918 | goto out; | |
919 | radix_tree_preload_end(); | |
920 | ||
921 | if (sgp != SGP_READ && !prealloc_page) { | |
41ffe5d5 | 922 | prealloc_page = shmem_alloc_page(gfp, info, index); |
27ab7006 HD |
923 | if (prealloc_page) { |
924 | SetPageSwapBacked(prealloc_page); | |
925 | if (mem_cgroup_cache_charge(prealloc_page, | |
926 | current->mm, GFP_KERNEL)) { | |
927 | page_cache_release(prealloc_page); | |
928 | prealloc_page = NULL; | |
ff36b801 SL |
929 | } |
930 | } | |
b409f9fc | 931 | } |
1da177e4 LT |
932 | |
933 | spin_lock(&info->lock); | |
934 | shmem_recalc_inode(inode); | |
41ffe5d5 | 935 | swap = shmem_get_swap(info, index); |
1da177e4 LT |
936 | if (swap.val) { |
937 | /* Look it up and read it in.. */ | |
27ab7006 HD |
938 | page = lookup_swap_cache(swap); |
939 | if (!page) { | |
456f998e | 940 | spin_unlock(&info->lock); |
1da177e4 | 941 | /* here we actually do the io */ |
68da9f05 HD |
942 | if (fault_type) |
943 | *fault_type |= VM_FAULT_MAJOR; | |
41ffe5d5 | 944 | page = shmem_swapin(swap, gfp, info, index); |
27ab7006 | 945 | if (!page) { |
41ffe5d5 | 946 | swp_entry_t nswap = shmem_get_swap(info, index); |
285b2c4f HD |
947 | if (nswap.val == swap.val) { |
948 | error = -ENOMEM; | |
27ab7006 | 949 | goto out; |
285b2c4f | 950 | } |
1da177e4 LT |
951 | goto repeat; |
952 | } | |
27ab7006 HD |
953 | wait_on_page_locked(page); |
954 | page_cache_release(page); | |
1da177e4 LT |
955 | goto repeat; |
956 | } | |
957 | ||
958 | /* We have to do this with page locked to prevent races */ | |
27ab7006 | 959 | if (!trylock_page(page)) { |
1da177e4 | 960 | spin_unlock(&info->lock); |
27ab7006 HD |
961 | wait_on_page_locked(page); |
962 | page_cache_release(page); | |
1da177e4 LT |
963 | goto repeat; |
964 | } | |
27ab7006 | 965 | if (PageWriteback(page)) { |
1da177e4 | 966 | spin_unlock(&info->lock); |
27ab7006 HD |
967 | wait_on_page_writeback(page); |
968 | unlock_page(page); | |
969 | page_cache_release(page); | |
1da177e4 LT |
970 | goto repeat; |
971 | } | |
27ab7006 | 972 | if (!PageUptodate(page)) { |
1da177e4 | 973 | spin_unlock(&info->lock); |
27ab7006 HD |
974 | unlock_page(page); |
975 | page_cache_release(page); | |
1da177e4 | 976 | error = -EIO; |
27ab7006 | 977 | goto out; |
1da177e4 LT |
978 | } |
979 | ||
27ab7006 | 980 | error = add_to_page_cache_locked(page, mapping, |
41ffe5d5 | 981 | index, GFP_NOWAIT); |
27ab7006 | 982 | if (error) { |
1da177e4 | 983 | spin_unlock(&info->lock); |
82369553 | 984 | if (error == -ENOMEM) { |
ae3abae6 DN |
985 | /* |
986 | * reclaim from proper memory cgroup and | |
987 | * call memcg's OOM if needed. | |
988 | */ | |
989 | error = mem_cgroup_shmem_charge_fallback( | |
27ab7006 | 990 | page, current->mm, gfp); |
b5a84319 | 991 | if (error) { |
27ab7006 HD |
992 | unlock_page(page); |
993 | page_cache_release(page); | |
994 | goto out; | |
b5a84319 | 995 | } |
82369553 | 996 | } |
27ab7006 HD |
997 | unlock_page(page); |
998 | page_cache_release(page); | |
1da177e4 LT |
999 | goto repeat; |
1000 | } | |
27ab7006 | 1001 | |
27ab7006 | 1002 | delete_from_swap_cache(page); |
41ffe5d5 | 1003 | shmem_put_swap(info, index, (swp_entry_t){0}); |
285b2c4f | 1004 | info->swapped--; |
27ab7006 HD |
1005 | spin_unlock(&info->lock); |
1006 | set_page_dirty(page); | |
1007 | swap_free(swap); | |
1008 | ||
1009 | } else if (sgp == SGP_READ) { | |
41ffe5d5 | 1010 | page = find_get_page(mapping, index); |
27ab7006 | 1011 | if (page && !trylock_page(page)) { |
1da177e4 | 1012 | spin_unlock(&info->lock); |
27ab7006 HD |
1013 | wait_on_page_locked(page); |
1014 | page_cache_release(page); | |
1da177e4 LT |
1015 | goto repeat; |
1016 | } | |
1017 | spin_unlock(&info->lock); | |
e83c32e8 HD |
1018 | |
1019 | } else if (prealloc_page) { | |
1da177e4 | 1020 | sbinfo = SHMEM_SB(inode->i_sb); |
0edd73b3 | 1021 | if (sbinfo->max_blocks) { |
fc5da22a HD |
1022 | if (percpu_counter_compare(&sbinfo->used_blocks, |
1023 | sbinfo->max_blocks) >= 0 || | |
59a16ead HD |
1024 | shmem_acct_block(info->flags)) |
1025 | goto nospace; | |
7e496299 | 1026 | percpu_counter_inc(&sbinfo->used_blocks); |
1da177e4 | 1027 | inode->i_blocks += BLOCKS_PER_PAGE; |
59a16ead HD |
1028 | } else if (shmem_acct_block(info->flags)) |
1029 | goto nospace; | |
1da177e4 | 1030 | |
27ab7006 HD |
1031 | page = prealloc_page; |
1032 | prealloc_page = NULL; | |
1da177e4 | 1033 | |
41ffe5d5 | 1034 | swap = shmem_get_swap(info, index); |
285b2c4f | 1035 | if (swap.val) |
27ab7006 HD |
1036 | mem_cgroup_uncharge_cache_page(page); |
1037 | else | |
285b2c4f | 1038 | error = add_to_page_cache_lru(page, mapping, |
41ffe5d5 | 1039 | index, GFP_NOWAIT); |
27ab7006 HD |
1040 | /* |
1041 | * At add_to_page_cache_lru() failure, | |
1042 | * uncharge will be done automatically. | |
1043 | */ | |
285b2c4f | 1044 | if (swap.val || error) { |
27ab7006 HD |
1045 | shmem_unacct_blocks(info->flags, 1); |
1046 | shmem_free_blocks(inode, 1); | |
1047 | spin_unlock(&info->lock); | |
1048 | page_cache_release(page); | |
27ab7006 | 1049 | goto repeat; |
1da177e4 LT |
1050 | } |
1051 | ||
1052 | info->alloced++; | |
1053 | spin_unlock(&info->lock); | |
27ab7006 HD |
1054 | clear_highpage(page); |
1055 | flush_dcache_page(page); | |
1056 | SetPageUptodate(page); | |
a0ee5ec5 | 1057 | if (sgp == SGP_DIRTY) |
27ab7006 HD |
1058 | set_page_dirty(page); |
1059 | ||
e83c32e8 HD |
1060 | } else { |
1061 | spin_unlock(&info->lock); | |
1062 | error = -ENOMEM; | |
1063 | goto out; | |
1da177e4 LT |
1064 | } |
1065 | done: | |
27ab7006 | 1066 | *pagep = page; |
ff36b801 | 1067 | error = 0; |
e83c32e8 HD |
1068 | out: |
1069 | if (prealloc_page) { | |
1070 | mem_cgroup_uncharge_cache_page(prealloc_page); | |
1071 | page_cache_release(prealloc_page); | |
1072 | } | |
1073 | return error; | |
1da177e4 | 1074 | |
59a16ead HD |
1075 | nospace: |
1076 | /* | |
1077 | * Perhaps the page was brought in from swap between find_lock_page | |
1078 | * and taking info->lock? We allow for that at add_to_page_cache_lru, | |
1079 | * but must also avoid reporting a spurious ENOSPC while working on a | |
9276aad6 | 1080 | * full tmpfs. |
59a16ead | 1081 | */ |
41ffe5d5 | 1082 | page = find_get_page(mapping, index); |
59a16ead | 1083 | spin_unlock(&info->lock); |
27ab7006 HD |
1084 | if (page) { |
1085 | page_cache_release(page); | |
1086 | goto repeat; | |
ff36b801 | 1087 | } |
27ab7006 | 1088 | error = -ENOSPC; |
e83c32e8 | 1089 | goto out; |
1da177e4 LT |
1090 | } |
1091 | ||
d0217ac0 | 1092 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1093 | { |
d3ac7f89 | 1094 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1095 | int error; |
68da9f05 | 1096 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 1097 | |
d0217ac0 NP |
1098 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1099 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1100 | |
27d54b39 | 1101 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1102 | if (error) |
1103 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 1104 | |
456f998e YH |
1105 | if (ret & VM_FAULT_MAJOR) { |
1106 | count_vm_event(PGMAJFAULT); | |
1107 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
1108 | } | |
68da9f05 | 1109 | return ret; |
1da177e4 LT |
1110 | } |
1111 | ||
1da177e4 | 1112 | #ifdef CONFIG_NUMA |
41ffe5d5 | 1113 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
1da177e4 | 1114 | { |
41ffe5d5 HD |
1115 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1116 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); | |
1da177e4 LT |
1117 | } |
1118 | ||
d8dc74f2 AB |
1119 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1120 | unsigned long addr) | |
1da177e4 | 1121 | { |
41ffe5d5 HD |
1122 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1123 | pgoff_t index; | |
1da177e4 | 1124 | |
41ffe5d5 HD |
1125 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
1126 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
1da177e4 LT |
1127 | } |
1128 | #endif | |
1129 | ||
1130 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1131 | { | |
d3ac7f89 | 1132 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1133 | struct shmem_inode_info *info = SHMEM_I(inode); |
1134 | int retval = -ENOMEM; | |
1135 | ||
1136 | spin_lock(&info->lock); | |
1137 | if (lock && !(info->flags & VM_LOCKED)) { | |
1138 | if (!user_shm_lock(inode->i_size, user)) | |
1139 | goto out_nomem; | |
1140 | info->flags |= VM_LOCKED; | |
89e004ea | 1141 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1142 | } |
1143 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1144 | user_shm_unlock(inode->i_size, user); | |
1145 | info->flags &= ~VM_LOCKED; | |
89e004ea LS |
1146 | mapping_clear_unevictable(file->f_mapping); |
1147 | scan_mapping_unevictable_pages(file->f_mapping); | |
1da177e4 LT |
1148 | } |
1149 | retval = 0; | |
89e004ea | 1150 | |
1da177e4 LT |
1151 | out_nomem: |
1152 | spin_unlock(&info->lock); | |
1153 | return retval; | |
1154 | } | |
1155 | ||
9b83a6a8 | 1156 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1157 | { |
1158 | file_accessed(file); | |
1159 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1160 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1161 | return 0; |
1162 | } | |
1163 | ||
454abafe DM |
1164 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
1165 | int mode, dev_t dev, unsigned long flags) | |
1da177e4 LT |
1166 | { |
1167 | struct inode *inode; | |
1168 | struct shmem_inode_info *info; | |
1169 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1170 | ||
5b04c689 PE |
1171 | if (shmem_reserve_inode(sb)) |
1172 | return NULL; | |
1da177e4 LT |
1173 | |
1174 | inode = new_inode(sb); | |
1175 | if (inode) { | |
85fe4025 | 1176 | inode->i_ino = get_next_ino(); |
454abafe | 1177 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1178 | inode->i_blocks = 0; |
1da177e4 LT |
1179 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1180 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1181 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1182 | info = SHMEM_I(inode); |
1183 | memset(info, 0, (char *)inode - (char *)info); | |
1184 | spin_lock_init(&info->lock); | |
0b0a0806 | 1185 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1186 | INIT_LIST_HEAD(&info->swaplist); |
b09e0fa4 | 1187 | INIT_LIST_HEAD(&info->xattr_list); |
72c04902 | 1188 | cache_no_acl(inode); |
1da177e4 LT |
1189 | |
1190 | switch (mode & S_IFMT) { | |
1191 | default: | |
39f0247d | 1192 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1193 | init_special_inode(inode, mode, dev); |
1194 | break; | |
1195 | case S_IFREG: | |
14fcc23f | 1196 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1197 | inode->i_op = &shmem_inode_operations; |
1198 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1199 | mpol_shared_policy_init(&info->policy, |
1200 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1201 | break; |
1202 | case S_IFDIR: | |
d8c76e6f | 1203 | inc_nlink(inode); |
1da177e4 LT |
1204 | /* Some things misbehave if size == 0 on a directory */ |
1205 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1206 | inode->i_op = &shmem_dir_inode_operations; | |
1207 | inode->i_fop = &simple_dir_operations; | |
1208 | break; | |
1209 | case S_IFLNK: | |
1210 | /* | |
1211 | * Must not load anything in the rbtree, | |
1212 | * mpol_free_shared_policy will not be called. | |
1213 | */ | |
71fe804b | 1214 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1215 | break; |
1216 | } | |
5b04c689 PE |
1217 | } else |
1218 | shmem_free_inode(sb); | |
1da177e4 LT |
1219 | return inode; |
1220 | } | |
1221 | ||
1222 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1223 | static const struct inode_operations shmem_symlink_inode_operations; |
1224 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 | 1225 | |
1da177e4 | 1226 | static int |
800d15a5 NP |
1227 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1228 | loff_t pos, unsigned len, unsigned flags, | |
1229 | struct page **pagep, void **fsdata) | |
1da177e4 | 1230 | { |
800d15a5 NP |
1231 | struct inode *inode = mapping->host; |
1232 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
800d15a5 NP |
1233 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
1234 | } | |
1235 | ||
1236 | static int | |
1237 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1238 | loff_t pos, unsigned len, unsigned copied, | |
1239 | struct page *page, void *fsdata) | |
1240 | { | |
1241 | struct inode *inode = mapping->host; | |
1242 | ||
d3602444 HD |
1243 | if (pos + copied > inode->i_size) |
1244 | i_size_write(inode, pos + copied); | |
1245 | ||
800d15a5 | 1246 | set_page_dirty(page); |
6746aff7 | 1247 | unlock_page(page); |
800d15a5 NP |
1248 | page_cache_release(page); |
1249 | ||
800d15a5 | 1250 | return copied; |
1da177e4 LT |
1251 | } |
1252 | ||
1da177e4 LT |
1253 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1254 | { | |
d3ac7f89 | 1255 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 | 1256 | struct address_space *mapping = inode->i_mapping; |
41ffe5d5 HD |
1257 | pgoff_t index; |
1258 | unsigned long offset; | |
a0ee5ec5 HD |
1259 | enum sgp_type sgp = SGP_READ; |
1260 | ||
1261 | /* | |
1262 | * Might this read be for a stacking filesystem? Then when reading | |
1263 | * holes of a sparse file, we actually need to allocate those pages, | |
1264 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1265 | */ | |
1266 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1267 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1268 | |
1269 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1270 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1271 | ||
1272 | for (;;) { | |
1273 | struct page *page = NULL; | |
41ffe5d5 HD |
1274 | pgoff_t end_index; |
1275 | unsigned long nr, ret; | |
1da177e4 LT |
1276 | loff_t i_size = i_size_read(inode); |
1277 | ||
1278 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1279 | if (index > end_index) | |
1280 | break; | |
1281 | if (index == end_index) { | |
1282 | nr = i_size & ~PAGE_CACHE_MASK; | |
1283 | if (nr <= offset) | |
1284 | break; | |
1285 | } | |
1286 | ||
a0ee5ec5 | 1287 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1288 | if (desc->error) { |
1289 | if (desc->error == -EINVAL) | |
1290 | desc->error = 0; | |
1291 | break; | |
1292 | } | |
d3602444 HD |
1293 | if (page) |
1294 | unlock_page(page); | |
1da177e4 LT |
1295 | |
1296 | /* | |
1297 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1298 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1299 | */ |
1300 | nr = PAGE_CACHE_SIZE; | |
1301 | i_size = i_size_read(inode); | |
1302 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1303 | if (index == end_index) { | |
1304 | nr = i_size & ~PAGE_CACHE_MASK; | |
1305 | if (nr <= offset) { | |
1306 | if (page) | |
1307 | page_cache_release(page); | |
1308 | break; | |
1309 | } | |
1310 | } | |
1311 | nr -= offset; | |
1312 | ||
1313 | if (page) { | |
1314 | /* | |
1315 | * If users can be writing to this page using arbitrary | |
1316 | * virtual addresses, take care about potential aliasing | |
1317 | * before reading the page on the kernel side. | |
1318 | */ | |
1319 | if (mapping_writably_mapped(mapping)) | |
1320 | flush_dcache_page(page); | |
1321 | /* | |
1322 | * Mark the page accessed if we read the beginning. | |
1323 | */ | |
1324 | if (!offset) | |
1325 | mark_page_accessed(page); | |
b5810039 | 1326 | } else { |
1da177e4 | 1327 | page = ZERO_PAGE(0); |
b5810039 NP |
1328 | page_cache_get(page); |
1329 | } | |
1da177e4 LT |
1330 | |
1331 | /* | |
1332 | * Ok, we have the page, and it's up-to-date, so | |
1333 | * now we can copy it to user space... | |
1334 | * | |
1335 | * The actor routine returns how many bytes were actually used.. | |
1336 | * NOTE! This may not be the same as how much of a user buffer | |
1337 | * we filled up (we may be padding etc), so we can only update | |
1338 | * "pos" here (the actor routine has to update the user buffer | |
1339 | * pointers and the remaining count). | |
1340 | */ | |
1341 | ret = actor(desc, page, offset, nr); | |
1342 | offset += ret; | |
1343 | index += offset >> PAGE_CACHE_SHIFT; | |
1344 | offset &= ~PAGE_CACHE_MASK; | |
1345 | ||
1346 | page_cache_release(page); | |
1347 | if (ret != nr || !desc->count) | |
1348 | break; | |
1349 | ||
1350 | cond_resched(); | |
1351 | } | |
1352 | ||
1353 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1354 | file_accessed(filp); | |
1355 | } | |
1356 | ||
bcd78e49 HD |
1357 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1358 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1359 | { | |
1360 | struct file *filp = iocb->ki_filp; | |
1361 | ssize_t retval; | |
1362 | unsigned long seg; | |
1363 | size_t count; | |
1364 | loff_t *ppos = &iocb->ki_pos; | |
1365 | ||
1366 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1367 | if (retval) | |
1368 | return retval; | |
1369 | ||
1370 | for (seg = 0; seg < nr_segs; seg++) { | |
1371 | read_descriptor_t desc; | |
1372 | ||
1373 | desc.written = 0; | |
1374 | desc.arg.buf = iov[seg].iov_base; | |
1375 | desc.count = iov[seg].iov_len; | |
1376 | if (desc.count == 0) | |
1377 | continue; | |
1378 | desc.error = 0; | |
1379 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1380 | retval += desc.written; | |
1381 | if (desc.error) { | |
1382 | retval = retval ?: desc.error; | |
1383 | break; | |
1384 | } | |
1385 | if (desc.count > 0) | |
1386 | break; | |
1387 | } | |
1388 | return retval; | |
1da177e4 LT |
1389 | } |
1390 | ||
708e3508 HD |
1391 | static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
1392 | struct pipe_inode_info *pipe, size_t len, | |
1393 | unsigned int flags) | |
1394 | { | |
1395 | struct address_space *mapping = in->f_mapping; | |
71f0e07a | 1396 | struct inode *inode = mapping->host; |
708e3508 HD |
1397 | unsigned int loff, nr_pages, req_pages; |
1398 | struct page *pages[PIPE_DEF_BUFFERS]; | |
1399 | struct partial_page partial[PIPE_DEF_BUFFERS]; | |
1400 | struct page *page; | |
1401 | pgoff_t index, end_index; | |
1402 | loff_t isize, left; | |
1403 | int error, page_nr; | |
1404 | struct splice_pipe_desc spd = { | |
1405 | .pages = pages, | |
1406 | .partial = partial, | |
1407 | .flags = flags, | |
1408 | .ops = &page_cache_pipe_buf_ops, | |
1409 | .spd_release = spd_release_page, | |
1410 | }; | |
1411 | ||
71f0e07a | 1412 | isize = i_size_read(inode); |
708e3508 HD |
1413 | if (unlikely(*ppos >= isize)) |
1414 | return 0; | |
1415 | ||
1416 | left = isize - *ppos; | |
1417 | if (unlikely(left < len)) | |
1418 | len = left; | |
1419 | ||
1420 | if (splice_grow_spd(pipe, &spd)) | |
1421 | return -ENOMEM; | |
1422 | ||
1423 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1424 | loff = *ppos & ~PAGE_CACHE_MASK; | |
1425 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1426 | nr_pages = min(req_pages, pipe->buffers); | |
1427 | ||
708e3508 HD |
1428 | spd.nr_pages = find_get_pages_contig(mapping, index, |
1429 | nr_pages, spd.pages); | |
1430 | index += spd.nr_pages; | |
708e3508 | 1431 | error = 0; |
708e3508 | 1432 | |
71f0e07a | 1433 | while (spd.nr_pages < nr_pages) { |
71f0e07a HD |
1434 | error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
1435 | if (error) | |
1436 | break; | |
1437 | unlock_page(page); | |
708e3508 HD |
1438 | spd.pages[spd.nr_pages++] = page; |
1439 | index++; | |
1440 | } | |
1441 | ||
708e3508 HD |
1442 | index = *ppos >> PAGE_CACHE_SHIFT; |
1443 | nr_pages = spd.nr_pages; | |
1444 | spd.nr_pages = 0; | |
71f0e07a | 1445 | |
708e3508 HD |
1446 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
1447 | unsigned int this_len; | |
1448 | ||
1449 | if (!len) | |
1450 | break; | |
1451 | ||
708e3508 HD |
1452 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
1453 | page = spd.pages[page_nr]; | |
1454 | ||
71f0e07a | 1455 | if (!PageUptodate(page) || page->mapping != mapping) { |
71f0e07a HD |
1456 | error = shmem_getpage(inode, index, &page, |
1457 | SGP_CACHE, NULL); | |
1458 | if (error) | |
708e3508 | 1459 | break; |
71f0e07a HD |
1460 | unlock_page(page); |
1461 | page_cache_release(spd.pages[page_nr]); | |
1462 | spd.pages[page_nr] = page; | |
708e3508 | 1463 | } |
71f0e07a HD |
1464 | |
1465 | isize = i_size_read(inode); | |
708e3508 HD |
1466 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
1467 | if (unlikely(!isize || index > end_index)) | |
1468 | break; | |
1469 | ||
708e3508 HD |
1470 | if (end_index == index) { |
1471 | unsigned int plen; | |
1472 | ||
708e3508 HD |
1473 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
1474 | if (plen <= loff) | |
1475 | break; | |
1476 | ||
708e3508 HD |
1477 | this_len = min(this_len, plen - loff); |
1478 | len = this_len; | |
1479 | } | |
1480 | ||
1481 | spd.partial[page_nr].offset = loff; | |
1482 | spd.partial[page_nr].len = this_len; | |
1483 | len -= this_len; | |
1484 | loff = 0; | |
1485 | spd.nr_pages++; | |
1486 | index++; | |
1487 | } | |
1488 | ||
708e3508 HD |
1489 | while (page_nr < nr_pages) |
1490 | page_cache_release(spd.pages[page_nr++]); | |
708e3508 HD |
1491 | |
1492 | if (spd.nr_pages) | |
1493 | error = splice_to_pipe(pipe, &spd); | |
1494 | ||
1495 | splice_shrink_spd(pipe, &spd); | |
1496 | ||
1497 | if (error > 0) { | |
1498 | *ppos += error; | |
1499 | file_accessed(in); | |
1500 | } | |
1501 | return error; | |
1502 | } | |
1503 | ||
726c3342 | 1504 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1505 | { |
726c3342 | 1506 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1507 | |
1508 | buf->f_type = TMPFS_MAGIC; | |
1509 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1510 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1511 | if (sbinfo->max_blocks) { |
1da177e4 | 1512 | buf->f_blocks = sbinfo->max_blocks; |
41ffe5d5 HD |
1513 | buf->f_bavail = |
1514 | buf->f_bfree = sbinfo->max_blocks - | |
1515 | percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1516 | } |
1517 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1518 | buf->f_files = sbinfo->max_inodes; |
1519 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1520 | } |
1521 | /* else leave those fields 0 like simple_statfs */ | |
1522 | return 0; | |
1523 | } | |
1524 | ||
1525 | /* | |
1526 | * File creation. Allocate an inode, and we're done.. | |
1527 | */ | |
1528 | static int | |
1529 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1530 | { | |
0b0a0806 | 1531 | struct inode *inode; |
1da177e4 LT |
1532 | int error = -ENOSPC; |
1533 | ||
454abafe | 1534 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1535 | if (inode) { |
2a7dba39 EP |
1536 | error = security_inode_init_security(inode, dir, |
1537 | &dentry->d_name, NULL, | |
1538 | NULL, NULL); | |
570bc1c2 SS |
1539 | if (error) { |
1540 | if (error != -EOPNOTSUPP) { | |
1541 | iput(inode); | |
1542 | return error; | |
1543 | } | |
39f0247d | 1544 | } |
1c7c474c CH |
1545 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1546 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1547 | if (error) { |
1548 | iput(inode); | |
1549 | return error; | |
570bc1c2 | 1550 | } |
718deb6b AV |
1551 | #else |
1552 | error = 0; | |
1c7c474c | 1553 | #endif |
1da177e4 LT |
1554 | dir->i_size += BOGO_DIRENT_SIZE; |
1555 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1556 | d_instantiate(dentry, inode); | |
1557 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1558 | } |
1559 | return error; | |
1560 | } | |
1561 | ||
1562 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1563 | { | |
1564 | int error; | |
1565 | ||
1566 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1567 | return error; | |
d8c76e6f | 1568 | inc_nlink(dir); |
1da177e4 LT |
1569 | return 0; |
1570 | } | |
1571 | ||
1572 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1573 | struct nameidata *nd) | |
1574 | { | |
1575 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1576 | } | |
1577 | ||
1578 | /* | |
1579 | * Link a file.. | |
1580 | */ | |
1581 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1582 | { | |
1583 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1584 | int ret; |
1da177e4 LT |
1585 | |
1586 | /* | |
1587 | * No ordinary (disk based) filesystem counts links as inodes; | |
1588 | * but each new link needs a new dentry, pinning lowmem, and | |
1589 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1590 | */ | |
5b04c689 PE |
1591 | ret = shmem_reserve_inode(inode->i_sb); |
1592 | if (ret) | |
1593 | goto out; | |
1da177e4 LT |
1594 | |
1595 | dir->i_size += BOGO_DIRENT_SIZE; | |
1596 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1597 | inc_nlink(inode); |
7de9c6ee | 1598 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1599 | dget(dentry); /* Extra pinning count for the created dentry */ |
1600 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1601 | out: |
1602 | return ret; | |
1da177e4 LT |
1603 | } |
1604 | ||
1605 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1606 | { | |
1607 | struct inode *inode = dentry->d_inode; | |
1608 | ||
5b04c689 PE |
1609 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1610 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1611 | |
1612 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1613 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1614 | drop_nlink(inode); |
1da177e4 LT |
1615 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1616 | return 0; | |
1617 | } | |
1618 | ||
1619 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1620 | { | |
1621 | if (!simple_empty(dentry)) | |
1622 | return -ENOTEMPTY; | |
1623 | ||
9a53c3a7 DH |
1624 | drop_nlink(dentry->d_inode); |
1625 | drop_nlink(dir); | |
1da177e4 LT |
1626 | return shmem_unlink(dir, dentry); |
1627 | } | |
1628 | ||
1629 | /* | |
1630 | * The VFS layer already does all the dentry stuff for rename, | |
1631 | * we just have to decrement the usage count for the target if | |
1632 | * it exists so that the VFS layer correctly free's it when it | |
1633 | * gets overwritten. | |
1634 | */ | |
1635 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1636 | { | |
1637 | struct inode *inode = old_dentry->d_inode; | |
1638 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1639 | ||
1640 | if (!simple_empty(new_dentry)) | |
1641 | return -ENOTEMPTY; | |
1642 | ||
1643 | if (new_dentry->d_inode) { | |
1644 | (void) shmem_unlink(new_dir, new_dentry); | |
1645 | if (they_are_dirs) | |
9a53c3a7 | 1646 | drop_nlink(old_dir); |
1da177e4 | 1647 | } else if (they_are_dirs) { |
9a53c3a7 | 1648 | drop_nlink(old_dir); |
d8c76e6f | 1649 | inc_nlink(new_dir); |
1da177e4 LT |
1650 | } |
1651 | ||
1652 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1653 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1654 | old_dir->i_ctime = old_dir->i_mtime = | |
1655 | new_dir->i_ctime = new_dir->i_mtime = | |
1656 | inode->i_ctime = CURRENT_TIME; | |
1657 | return 0; | |
1658 | } | |
1659 | ||
1660 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1661 | { | |
1662 | int error; | |
1663 | int len; | |
1664 | struct inode *inode; | |
9276aad6 | 1665 | struct page *page; |
1da177e4 LT |
1666 | char *kaddr; |
1667 | struct shmem_inode_info *info; | |
1668 | ||
1669 | len = strlen(symname) + 1; | |
1670 | if (len > PAGE_CACHE_SIZE) | |
1671 | return -ENAMETOOLONG; | |
1672 | ||
454abafe | 1673 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
1674 | if (!inode) |
1675 | return -ENOSPC; | |
1676 | ||
2a7dba39 EP |
1677 | error = security_inode_init_security(inode, dir, &dentry->d_name, NULL, |
1678 | NULL, NULL); | |
570bc1c2 SS |
1679 | if (error) { |
1680 | if (error != -EOPNOTSUPP) { | |
1681 | iput(inode); | |
1682 | return error; | |
1683 | } | |
1684 | error = 0; | |
1685 | } | |
1686 | ||
1da177e4 LT |
1687 | info = SHMEM_I(inode); |
1688 | inode->i_size = len-1; | |
b09e0fa4 | 1689 | if (len <= SHMEM_SYMLINK_INLINE_LEN) { |
1da177e4 | 1690 | /* do it inline */ |
b09e0fa4 | 1691 | memcpy(info->inline_symlink, symname, len); |
1da177e4 LT |
1692 | inode->i_op = &shmem_symlink_inline_operations; |
1693 | } else { | |
1694 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1695 | if (error) { | |
1696 | iput(inode); | |
1697 | return error; | |
1698 | } | |
14fcc23f | 1699 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1700 | inode->i_op = &shmem_symlink_inode_operations; |
1701 | kaddr = kmap_atomic(page, KM_USER0); | |
1702 | memcpy(kaddr, symname, len); | |
1703 | kunmap_atomic(kaddr, KM_USER0); | |
1704 | set_page_dirty(page); | |
6746aff7 | 1705 | unlock_page(page); |
1da177e4 LT |
1706 | page_cache_release(page); |
1707 | } | |
1da177e4 LT |
1708 | dir->i_size += BOGO_DIRENT_SIZE; |
1709 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1710 | d_instantiate(dentry, inode); | |
1711 | dget(dentry); | |
1712 | return 0; | |
1713 | } | |
1714 | ||
cc314eef | 1715 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 1716 | { |
b09e0fa4 | 1717 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink); |
cc314eef | 1718 | return NULL; |
1da177e4 LT |
1719 | } |
1720 | ||
cc314eef | 1721 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1722 | { |
1723 | struct page *page = NULL; | |
41ffe5d5 HD |
1724 | int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
1725 | nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); | |
d3602444 HD |
1726 | if (page) |
1727 | unlock_page(page); | |
cc314eef | 1728 | return page; |
1da177e4 LT |
1729 | } |
1730 | ||
cc314eef | 1731 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1732 | { |
1733 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1734 | struct page *page = cookie; |
1da177e4 LT |
1735 | kunmap(page); |
1736 | mark_page_accessed(page); | |
1737 | page_cache_release(page); | |
1da177e4 LT |
1738 | } |
1739 | } | |
1740 | ||
b09e0fa4 | 1741 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 1742 | /* |
b09e0fa4 EP |
1743 | * Superblocks without xattr inode operations may get some security.* xattr |
1744 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
1745 | * like ACLs, we also need to implement the security.* handlers at |
1746 | * filesystem level, though. | |
1747 | */ | |
1748 | ||
b09e0fa4 EP |
1749 | static int shmem_xattr_get(struct dentry *dentry, const char *name, |
1750 | void *buffer, size_t size) | |
39f0247d | 1751 | { |
b09e0fa4 EP |
1752 | struct shmem_inode_info *info; |
1753 | struct shmem_xattr *xattr; | |
1754 | int ret = -ENODATA; | |
39f0247d | 1755 | |
b09e0fa4 EP |
1756 | info = SHMEM_I(dentry->d_inode); |
1757 | ||
1758 | spin_lock(&info->lock); | |
1759 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1760 | if (strcmp(name, xattr->name)) | |
1761 | continue; | |
1762 | ||
1763 | ret = xattr->size; | |
1764 | if (buffer) { | |
1765 | if (size < xattr->size) | |
1766 | ret = -ERANGE; | |
1767 | else | |
1768 | memcpy(buffer, xattr->value, xattr->size); | |
1769 | } | |
1770 | break; | |
1771 | } | |
1772 | spin_unlock(&info->lock); | |
1773 | return ret; | |
39f0247d AG |
1774 | } |
1775 | ||
b09e0fa4 EP |
1776 | static int shmem_xattr_set(struct dentry *dentry, const char *name, |
1777 | const void *value, size_t size, int flags) | |
39f0247d | 1778 | { |
b09e0fa4 EP |
1779 | struct inode *inode = dentry->d_inode; |
1780 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1781 | struct shmem_xattr *xattr; | |
1782 | struct shmem_xattr *new_xattr = NULL; | |
1783 | size_t len; | |
1784 | int err = 0; | |
1785 | ||
1786 | /* value == NULL means remove */ | |
1787 | if (value) { | |
1788 | /* wrap around? */ | |
1789 | len = sizeof(*new_xattr) + size; | |
1790 | if (len <= sizeof(*new_xattr)) | |
1791 | return -ENOMEM; | |
1792 | ||
1793 | new_xattr = kmalloc(len, GFP_KERNEL); | |
1794 | if (!new_xattr) | |
1795 | return -ENOMEM; | |
1796 | ||
1797 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
1798 | if (!new_xattr->name) { | |
1799 | kfree(new_xattr); | |
1800 | return -ENOMEM; | |
1801 | } | |
1802 | ||
1803 | new_xattr->size = size; | |
1804 | memcpy(new_xattr->value, value, size); | |
1805 | } | |
1806 | ||
1807 | spin_lock(&info->lock); | |
1808 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1809 | if (!strcmp(name, xattr->name)) { | |
1810 | if (flags & XATTR_CREATE) { | |
1811 | xattr = new_xattr; | |
1812 | err = -EEXIST; | |
1813 | } else if (new_xattr) { | |
1814 | list_replace(&xattr->list, &new_xattr->list); | |
1815 | } else { | |
1816 | list_del(&xattr->list); | |
1817 | } | |
1818 | goto out; | |
1819 | } | |
1820 | } | |
1821 | if (flags & XATTR_REPLACE) { | |
1822 | xattr = new_xattr; | |
1823 | err = -ENODATA; | |
1824 | } else { | |
1825 | list_add(&new_xattr->list, &info->xattr_list); | |
1826 | xattr = NULL; | |
1827 | } | |
1828 | out: | |
1829 | spin_unlock(&info->lock); | |
1830 | if (xattr) | |
1831 | kfree(xattr->name); | |
1832 | kfree(xattr); | |
1833 | return err; | |
39f0247d AG |
1834 | } |
1835 | ||
bb435453 | 1836 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 1837 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1c7c474c CH |
1838 | &generic_acl_access_handler, |
1839 | &generic_acl_default_handler, | |
b09e0fa4 | 1840 | #endif |
39f0247d AG |
1841 | NULL |
1842 | }; | |
b09e0fa4 EP |
1843 | |
1844 | static int shmem_xattr_validate(const char *name) | |
1845 | { | |
1846 | struct { const char *prefix; size_t len; } arr[] = { | |
1847 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
1848 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
1849 | }; | |
1850 | int i; | |
1851 | ||
1852 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
1853 | size_t preflen = arr[i].len; | |
1854 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
1855 | if (!name[preflen]) | |
1856 | return -EINVAL; | |
1857 | return 0; | |
1858 | } | |
1859 | } | |
1860 | return -EOPNOTSUPP; | |
1861 | } | |
1862 | ||
1863 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
1864 | void *buffer, size_t size) | |
1865 | { | |
1866 | int err; | |
1867 | ||
1868 | /* | |
1869 | * If this is a request for a synthetic attribute in the system.* | |
1870 | * namespace use the generic infrastructure to resolve a handler | |
1871 | * for it via sb->s_xattr. | |
1872 | */ | |
1873 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1874 | return generic_getxattr(dentry, name, buffer, size); | |
1875 | ||
1876 | err = shmem_xattr_validate(name); | |
1877 | if (err) | |
1878 | return err; | |
1879 | ||
1880 | return shmem_xattr_get(dentry, name, buffer, size); | |
1881 | } | |
1882 | ||
1883 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
1884 | const void *value, size_t size, int flags) | |
1885 | { | |
1886 | int err; | |
1887 | ||
1888 | /* | |
1889 | * If this is a request for a synthetic attribute in the system.* | |
1890 | * namespace use the generic infrastructure to resolve a handler | |
1891 | * for it via sb->s_xattr. | |
1892 | */ | |
1893 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1894 | return generic_setxattr(dentry, name, value, size, flags); | |
1895 | ||
1896 | err = shmem_xattr_validate(name); | |
1897 | if (err) | |
1898 | return err; | |
1899 | ||
1900 | if (size == 0) | |
1901 | value = ""; /* empty EA, do not remove */ | |
1902 | ||
1903 | return shmem_xattr_set(dentry, name, value, size, flags); | |
1904 | ||
1905 | } | |
1906 | ||
1907 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
1908 | { | |
1909 | int err; | |
1910 | ||
1911 | /* | |
1912 | * If this is a request for a synthetic attribute in the system.* | |
1913 | * namespace use the generic infrastructure to resolve a handler | |
1914 | * for it via sb->s_xattr. | |
1915 | */ | |
1916 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1917 | return generic_removexattr(dentry, name); | |
1918 | ||
1919 | err = shmem_xattr_validate(name); | |
1920 | if (err) | |
1921 | return err; | |
1922 | ||
1923 | return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE); | |
1924 | } | |
1925 | ||
1926 | static bool xattr_is_trusted(const char *name) | |
1927 | { | |
1928 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
1929 | } | |
1930 | ||
1931 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
1932 | { | |
1933 | bool trusted = capable(CAP_SYS_ADMIN); | |
1934 | struct shmem_xattr *xattr; | |
1935 | struct shmem_inode_info *info; | |
1936 | size_t used = 0; | |
1937 | ||
1938 | info = SHMEM_I(dentry->d_inode); | |
1939 | ||
1940 | spin_lock(&info->lock); | |
1941 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1942 | size_t len; | |
1943 | ||
1944 | /* skip "trusted." attributes for unprivileged callers */ | |
1945 | if (!trusted && xattr_is_trusted(xattr->name)) | |
1946 | continue; | |
1947 | ||
1948 | len = strlen(xattr->name) + 1; | |
1949 | used += len; | |
1950 | if (buffer) { | |
1951 | if (size < used) { | |
1952 | used = -ERANGE; | |
1953 | break; | |
1954 | } | |
1955 | memcpy(buffer, xattr->name, len); | |
1956 | buffer += len; | |
1957 | } | |
1958 | } | |
1959 | spin_unlock(&info->lock); | |
1960 | ||
1961 | return used; | |
1962 | } | |
1963 | #endif /* CONFIG_TMPFS_XATTR */ | |
1964 | ||
1965 | static const struct inode_operations shmem_symlink_inline_operations = { | |
1966 | .readlink = generic_readlink, | |
1967 | .follow_link = shmem_follow_link_inline, | |
1968 | #ifdef CONFIG_TMPFS_XATTR | |
1969 | .setxattr = shmem_setxattr, | |
1970 | .getxattr = shmem_getxattr, | |
1971 | .listxattr = shmem_listxattr, | |
1972 | .removexattr = shmem_removexattr, | |
1973 | #endif | |
1974 | }; | |
1975 | ||
1976 | static const struct inode_operations shmem_symlink_inode_operations = { | |
1977 | .readlink = generic_readlink, | |
1978 | .follow_link = shmem_follow_link, | |
1979 | .put_link = shmem_put_link, | |
1980 | #ifdef CONFIG_TMPFS_XATTR | |
1981 | .setxattr = shmem_setxattr, | |
1982 | .getxattr = shmem_getxattr, | |
1983 | .listxattr = shmem_listxattr, | |
1984 | .removexattr = shmem_removexattr, | |
39f0247d | 1985 | #endif |
b09e0fa4 | 1986 | }; |
39f0247d | 1987 | |
91828a40 DG |
1988 | static struct dentry *shmem_get_parent(struct dentry *child) |
1989 | { | |
1990 | return ERR_PTR(-ESTALE); | |
1991 | } | |
1992 | ||
1993 | static int shmem_match(struct inode *ino, void *vfh) | |
1994 | { | |
1995 | __u32 *fh = vfh; | |
1996 | __u64 inum = fh[2]; | |
1997 | inum = (inum << 32) | fh[1]; | |
1998 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1999 | } | |
2000 | ||
480b116c CH |
2001 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2002 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2003 | { |
91828a40 | 2004 | struct inode *inode; |
480b116c CH |
2005 | struct dentry *dentry = NULL; |
2006 | u64 inum = fid->raw[2]; | |
2007 | inum = (inum << 32) | fid->raw[1]; | |
2008 | ||
2009 | if (fh_len < 3) | |
2010 | return NULL; | |
91828a40 | 2011 | |
480b116c CH |
2012 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2013 | shmem_match, fid->raw); | |
91828a40 | 2014 | if (inode) { |
480b116c | 2015 | dentry = d_find_alias(inode); |
91828a40 DG |
2016 | iput(inode); |
2017 | } | |
2018 | ||
480b116c | 2019 | return dentry; |
91828a40 DG |
2020 | } |
2021 | ||
2022 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2023 | int connectable) | |
2024 | { | |
2025 | struct inode *inode = dentry->d_inode; | |
2026 | ||
5fe0c237 AK |
2027 | if (*len < 3) { |
2028 | *len = 3; | |
91828a40 | 2029 | return 255; |
5fe0c237 | 2030 | } |
91828a40 | 2031 | |
1d3382cb | 2032 | if (inode_unhashed(inode)) { |
91828a40 DG |
2033 | /* Unfortunately insert_inode_hash is not idempotent, |
2034 | * so as we hash inodes here rather than at creation | |
2035 | * time, we need a lock to ensure we only try | |
2036 | * to do it once | |
2037 | */ | |
2038 | static DEFINE_SPINLOCK(lock); | |
2039 | spin_lock(&lock); | |
1d3382cb | 2040 | if (inode_unhashed(inode)) |
91828a40 DG |
2041 | __insert_inode_hash(inode, |
2042 | inode->i_ino + inode->i_generation); | |
2043 | spin_unlock(&lock); | |
2044 | } | |
2045 | ||
2046 | fh[0] = inode->i_generation; | |
2047 | fh[1] = inode->i_ino; | |
2048 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2049 | ||
2050 | *len = 3; | |
2051 | return 1; | |
2052 | } | |
2053 | ||
39655164 | 2054 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2055 | .get_parent = shmem_get_parent, |
91828a40 | 2056 | .encode_fh = shmem_encode_fh, |
480b116c | 2057 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2058 | }; |
2059 | ||
680d794b | 2060 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2061 | bool remount) | |
1da177e4 LT |
2062 | { |
2063 | char *this_char, *value, *rest; | |
2064 | ||
b00dc3ad HD |
2065 | while (options != NULL) { |
2066 | this_char = options; | |
2067 | for (;;) { | |
2068 | /* | |
2069 | * NUL-terminate this option: unfortunately, | |
2070 | * mount options form a comma-separated list, | |
2071 | * but mpol's nodelist may also contain commas. | |
2072 | */ | |
2073 | options = strchr(options, ','); | |
2074 | if (options == NULL) | |
2075 | break; | |
2076 | options++; | |
2077 | if (!isdigit(*options)) { | |
2078 | options[-1] = '\0'; | |
2079 | break; | |
2080 | } | |
2081 | } | |
1da177e4 LT |
2082 | if (!*this_char) |
2083 | continue; | |
2084 | if ((value = strchr(this_char,'=')) != NULL) { | |
2085 | *value++ = 0; | |
2086 | } else { | |
2087 | printk(KERN_ERR | |
2088 | "tmpfs: No value for mount option '%s'\n", | |
2089 | this_char); | |
2090 | return 1; | |
2091 | } | |
2092 | ||
2093 | if (!strcmp(this_char,"size")) { | |
2094 | unsigned long long size; | |
2095 | size = memparse(value,&rest); | |
2096 | if (*rest == '%') { | |
2097 | size <<= PAGE_SHIFT; | |
2098 | size *= totalram_pages; | |
2099 | do_div(size, 100); | |
2100 | rest++; | |
2101 | } | |
2102 | if (*rest) | |
2103 | goto bad_val; | |
680d794b | 2104 | sbinfo->max_blocks = |
2105 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2106 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2107 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2108 | if (*rest) |
2109 | goto bad_val; | |
2110 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2111 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2112 | if (*rest) |
2113 | goto bad_val; | |
2114 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2115 | if (remount) |
1da177e4 | 2116 | continue; |
680d794b | 2117 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2118 | if (*rest) |
2119 | goto bad_val; | |
2120 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2121 | if (remount) |
1da177e4 | 2122 | continue; |
680d794b | 2123 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2124 | if (*rest) |
2125 | goto bad_val; | |
2126 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2127 | if (remount) |
1da177e4 | 2128 | continue; |
680d794b | 2129 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2130 | if (*rest) |
2131 | goto bad_val; | |
7339ff83 | 2132 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2133 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2134 | goto bad_val; |
1da177e4 LT |
2135 | } else { |
2136 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2137 | this_char); | |
2138 | return 1; | |
2139 | } | |
2140 | } | |
2141 | return 0; | |
2142 | ||
2143 | bad_val: | |
2144 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2145 | value, this_char); | |
2146 | return 1; | |
2147 | ||
2148 | } | |
2149 | ||
2150 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2151 | { | |
2152 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2153 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2154 | unsigned long inodes; |
2155 | int error = -EINVAL; | |
2156 | ||
680d794b | 2157 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2158 | return error; |
1da177e4 | 2159 | |
0edd73b3 | 2160 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2161 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2162 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2163 | goto out; |
680d794b | 2164 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2165 | goto out; |
2166 | /* | |
2167 | * Those tests also disallow limited->unlimited while any are in | |
2168 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2169 | * but we must separately disallow unlimited->limited, because | |
2170 | * in that case we have no record of how much is already in use. | |
2171 | */ | |
680d794b | 2172 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2173 | goto out; |
680d794b | 2174 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2175 | goto out; |
2176 | ||
2177 | error = 0; | |
680d794b | 2178 | sbinfo->max_blocks = config.max_blocks; |
680d794b | 2179 | sbinfo->max_inodes = config.max_inodes; |
2180 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2181 | |
2182 | mpol_put(sbinfo->mpol); | |
2183 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2184 | out: |
2185 | spin_unlock(&sbinfo->stat_lock); | |
2186 | return error; | |
1da177e4 | 2187 | } |
680d794b | 2188 | |
2189 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
2190 | { | |
2191 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
2192 | ||
2193 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2194 | seq_printf(seq, ",size=%luk", | |
2195 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2196 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2197 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2198 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
2199 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
2200 | if (sbinfo->uid != 0) | |
2201 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2202 | if (sbinfo->gid != 0) | |
2203 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 2204 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b | 2205 | return 0; |
2206 | } | |
2207 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2208 | |
2209 | static void shmem_put_super(struct super_block *sb) | |
2210 | { | |
602586a8 HD |
2211 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2212 | ||
2213 | percpu_counter_destroy(&sbinfo->used_blocks); | |
2214 | kfree(sbinfo); | |
1da177e4 LT |
2215 | sb->s_fs_info = NULL; |
2216 | } | |
2217 | ||
2b2af54a | 2218 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2219 | { |
2220 | struct inode *inode; | |
2221 | struct dentry *root; | |
0edd73b3 | 2222 | struct shmem_sb_info *sbinfo; |
680d794b | 2223 | int err = -ENOMEM; |
2224 | ||
2225 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2226 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b | 2227 | L1_CACHE_BYTES), GFP_KERNEL); |
2228 | if (!sbinfo) | |
2229 | return -ENOMEM; | |
2230 | ||
680d794b | 2231 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2232 | sbinfo->uid = current_fsuid(); |
2233 | sbinfo->gid = current_fsgid(); | |
680d794b | 2234 | sb->s_fs_info = sbinfo; |
1da177e4 | 2235 | |
0edd73b3 | 2236 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2237 | /* |
2238 | * Per default we only allow half of the physical ram per | |
2239 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2240 | * but the internal instance is left unlimited. | |
2241 | */ | |
2242 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b | 2243 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2244 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2245 | if (shmem_parse_options(data, sbinfo, false)) { | |
2246 | err = -EINVAL; | |
2247 | goto failed; | |
2248 | } | |
1da177e4 | 2249 | } |
91828a40 | 2250 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2251 | #else |
2252 | sb->s_flags |= MS_NOUSER; | |
2253 | #endif | |
2254 | ||
0edd73b3 | 2255 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2256 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2257 | goto failed; | |
680d794b | 2258 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2259 | |
285b2c4f | 2260 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 LT |
2261 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2262 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2263 | sb->s_magic = TMPFS_MAGIC; | |
2264 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2265 | sb->s_time_gran = 1; |
b09e0fa4 | 2266 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2267 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2268 | #endif |
2269 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2270 | sb->s_flags |= MS_POSIXACL; |
2271 | #endif | |
0edd73b3 | 2272 | |
454abafe | 2273 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2274 | if (!inode) |
2275 | goto failed; | |
680d794b | 2276 | inode->i_uid = sbinfo->uid; |
2277 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2278 | root = d_alloc_root(inode); |
2279 | if (!root) | |
2280 | goto failed_iput; | |
2281 | sb->s_root = root; | |
2282 | return 0; | |
2283 | ||
2284 | failed_iput: | |
2285 | iput(inode); | |
2286 | failed: | |
2287 | shmem_put_super(sb); | |
2288 | return err; | |
2289 | } | |
2290 | ||
fcc234f8 | 2291 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2292 | |
2293 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2294 | { | |
41ffe5d5 HD |
2295 | struct shmem_inode_info *info; |
2296 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
2297 | if (!info) | |
1da177e4 | 2298 | return NULL; |
41ffe5d5 | 2299 | return &info->vfs_inode; |
1da177e4 LT |
2300 | } |
2301 | ||
41ffe5d5 | 2302 | static void shmem_destroy_callback(struct rcu_head *head) |
fa0d7e3d NP |
2303 | { |
2304 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
2305 | INIT_LIST_HEAD(&inode->i_dentry); | |
2306 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2307 | } | |
2308 | ||
1da177e4 LT |
2309 | static void shmem_destroy_inode(struct inode *inode) |
2310 | { | |
2311 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2312 | /* only struct inode is valid if it's an inline symlink */ | |
2313 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2314 | } | |
41ffe5d5 | 2315 | call_rcu(&inode->i_rcu, shmem_destroy_callback); |
1da177e4 LT |
2316 | } |
2317 | ||
41ffe5d5 | 2318 | static void shmem_init_inode(void *foo) |
1da177e4 | 2319 | { |
41ffe5d5 HD |
2320 | struct shmem_inode_info *info = foo; |
2321 | inode_init_once(&info->vfs_inode); | |
1da177e4 LT |
2322 | } |
2323 | ||
41ffe5d5 | 2324 | static int shmem_init_inodecache(void) |
1da177e4 LT |
2325 | { |
2326 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2327 | sizeof(struct shmem_inode_info), | |
41ffe5d5 | 2328 | 0, SLAB_PANIC, shmem_init_inode); |
1da177e4 LT |
2329 | return 0; |
2330 | } | |
2331 | ||
41ffe5d5 | 2332 | static void shmem_destroy_inodecache(void) |
1da177e4 | 2333 | { |
1a1d92c1 | 2334 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2335 | } |
2336 | ||
f5e54d6e | 2337 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2338 | .writepage = shmem_writepage, |
76719325 | 2339 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2340 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
2341 | .write_begin = shmem_write_begin, |
2342 | .write_end = shmem_write_end, | |
1da177e4 | 2343 | #endif |
304dbdb7 | 2344 | .migratepage = migrate_page, |
aa261f54 | 2345 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2346 | }; |
2347 | ||
15ad7cdc | 2348 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2349 | .mmap = shmem_mmap, |
2350 | #ifdef CONFIG_TMPFS | |
2351 | .llseek = generic_file_llseek, | |
bcd78e49 | 2352 | .read = do_sync_read, |
5402b976 | 2353 | .write = do_sync_write, |
bcd78e49 | 2354 | .aio_read = shmem_file_aio_read, |
5402b976 | 2355 | .aio_write = generic_file_aio_write, |
1b061d92 | 2356 | .fsync = noop_fsync, |
708e3508 | 2357 | .splice_read = shmem_file_splice_read, |
ae976416 | 2358 | .splice_write = generic_file_splice_write, |
1da177e4 LT |
2359 | #endif |
2360 | }; | |
2361 | ||
92e1d5be | 2362 | static const struct inode_operations shmem_inode_operations = { |
94c1e62d | 2363 | .setattr = shmem_setattr, |
f6b3ec23 | 2364 | .truncate_range = shmem_truncate_range, |
b09e0fa4 EP |
2365 | #ifdef CONFIG_TMPFS_XATTR |
2366 | .setxattr = shmem_setxattr, | |
2367 | .getxattr = shmem_getxattr, | |
2368 | .listxattr = shmem_listxattr, | |
2369 | .removexattr = shmem_removexattr, | |
2370 | #endif | |
1da177e4 LT |
2371 | }; |
2372 | ||
92e1d5be | 2373 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2374 | #ifdef CONFIG_TMPFS |
2375 | .create = shmem_create, | |
2376 | .lookup = simple_lookup, | |
2377 | .link = shmem_link, | |
2378 | .unlink = shmem_unlink, | |
2379 | .symlink = shmem_symlink, | |
2380 | .mkdir = shmem_mkdir, | |
2381 | .rmdir = shmem_rmdir, | |
2382 | .mknod = shmem_mknod, | |
2383 | .rename = shmem_rename, | |
1da177e4 | 2384 | #endif |
b09e0fa4 EP |
2385 | #ifdef CONFIG_TMPFS_XATTR |
2386 | .setxattr = shmem_setxattr, | |
2387 | .getxattr = shmem_getxattr, | |
2388 | .listxattr = shmem_listxattr, | |
2389 | .removexattr = shmem_removexattr, | |
2390 | #endif | |
39f0247d | 2391 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2392 | .setattr = shmem_setattr, |
39f0247d AG |
2393 | #endif |
2394 | }; | |
2395 | ||
92e1d5be | 2396 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2397 | #ifdef CONFIG_TMPFS_XATTR |
2398 | .setxattr = shmem_setxattr, | |
2399 | .getxattr = shmem_getxattr, | |
2400 | .listxattr = shmem_listxattr, | |
2401 | .removexattr = shmem_removexattr, | |
2402 | #endif | |
39f0247d | 2403 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2404 | .setattr = shmem_setattr, |
39f0247d | 2405 | #endif |
1da177e4 LT |
2406 | }; |
2407 | ||
759b9775 | 2408 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2409 | .alloc_inode = shmem_alloc_inode, |
2410 | .destroy_inode = shmem_destroy_inode, | |
2411 | #ifdef CONFIG_TMPFS | |
2412 | .statfs = shmem_statfs, | |
2413 | .remount_fs = shmem_remount_fs, | |
680d794b | 2414 | .show_options = shmem_show_options, |
1da177e4 | 2415 | #endif |
1f895f75 | 2416 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2417 | .drop_inode = generic_delete_inode, |
2418 | .put_super = shmem_put_super, | |
2419 | }; | |
2420 | ||
f0f37e2f | 2421 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2422 | .fault = shmem_fault, |
1da177e4 LT |
2423 | #ifdef CONFIG_NUMA |
2424 | .set_policy = shmem_set_policy, | |
2425 | .get_policy = shmem_get_policy, | |
2426 | #endif | |
2427 | }; | |
2428 | ||
3c26ff6e AV |
2429 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2430 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2431 | { |
3c26ff6e | 2432 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2433 | } |
2434 | ||
41ffe5d5 | 2435 | static struct file_system_type shmem_fs_type = { |
1da177e4 LT |
2436 | .owner = THIS_MODULE, |
2437 | .name = "tmpfs", | |
3c26ff6e | 2438 | .mount = shmem_mount, |
1da177e4 LT |
2439 | .kill_sb = kill_litter_super, |
2440 | }; | |
1da177e4 | 2441 | |
41ffe5d5 | 2442 | int __init shmem_init(void) |
1da177e4 LT |
2443 | { |
2444 | int error; | |
2445 | ||
e0bf68dd PZ |
2446 | error = bdi_init(&shmem_backing_dev_info); |
2447 | if (error) | |
2448 | goto out4; | |
2449 | ||
41ffe5d5 | 2450 | error = shmem_init_inodecache(); |
1da177e4 LT |
2451 | if (error) |
2452 | goto out3; | |
2453 | ||
41ffe5d5 | 2454 | error = register_filesystem(&shmem_fs_type); |
1da177e4 LT |
2455 | if (error) { |
2456 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2457 | goto out2; | |
2458 | } | |
95dc112a | 2459 | |
41ffe5d5 HD |
2460 | shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER, |
2461 | shmem_fs_type.name, NULL); | |
1da177e4 LT |
2462 | if (IS_ERR(shm_mnt)) { |
2463 | error = PTR_ERR(shm_mnt); | |
2464 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2465 | goto out1; | |
2466 | } | |
2467 | return 0; | |
2468 | ||
2469 | out1: | |
41ffe5d5 | 2470 | unregister_filesystem(&shmem_fs_type); |
1da177e4 | 2471 | out2: |
41ffe5d5 | 2472 | shmem_destroy_inodecache(); |
1da177e4 | 2473 | out3: |
e0bf68dd PZ |
2474 | bdi_destroy(&shmem_backing_dev_info); |
2475 | out4: | |
1da177e4 LT |
2476 | shm_mnt = ERR_PTR(error); |
2477 | return error; | |
2478 | } | |
853ac43a | 2479 | |
87946a72 DN |
2480 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2481 | /** | |
41ffe5d5 | 2482 | * mem_cgroup_get_shmem_target - find page or swap assigned to the shmem file |
87946a72 | 2483 | * @inode: the inode to be searched |
41ffe5d5 | 2484 | * @index: the page offset to be searched |
87946a72 | 2485 | * @pagep: the pointer for the found page to be stored |
41ffe5d5 | 2486 | * @swapp: the pointer for the found swap entry to be stored |
87946a72 DN |
2487 | * |
2488 | * If a page is found, refcount of it is incremented. Callers should handle | |
2489 | * these refcount. | |
2490 | */ | |
41ffe5d5 HD |
2491 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t index, |
2492 | struct page **pagep, swp_entry_t *swapp) | |
87946a72 | 2493 | { |
87946a72 | 2494 | struct shmem_inode_info *info = SHMEM_I(inode); |
41ffe5d5 HD |
2495 | struct page *page = NULL; |
2496 | swp_entry_t swap = {0}; | |
87946a72 | 2497 | |
41ffe5d5 | 2498 | if ((index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
87946a72 DN |
2499 | goto out; |
2500 | ||
2501 | spin_lock(&info->lock); | |
87946a72 | 2502 | #ifdef CONFIG_SWAP |
41ffe5d5 HD |
2503 | swap = shmem_get_swap(info, index); |
2504 | if (swap.val) | |
2505 | page = find_get_page(&swapper_space, swap.val); | |
285b2c4f | 2506 | else |
87946a72 | 2507 | #endif |
41ffe5d5 | 2508 | page = find_get_page(inode->i_mapping, index); |
87946a72 DN |
2509 | spin_unlock(&info->lock); |
2510 | out: | |
2511 | *pagep = page; | |
41ffe5d5 | 2512 | *swapp = swap; |
87946a72 DN |
2513 | } |
2514 | #endif | |
2515 | ||
853ac43a MM |
2516 | #else /* !CONFIG_SHMEM */ |
2517 | ||
2518 | /* | |
2519 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2520 | * | |
2521 | * This is intended for small system where the benefits of the full | |
2522 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2523 | * their complexity. On systems without swap this code should be | |
2524 | * effectively equivalent, but much lighter weight. | |
2525 | */ | |
2526 | ||
2527 | #include <linux/ramfs.h> | |
2528 | ||
41ffe5d5 | 2529 | static struct file_system_type shmem_fs_type = { |
853ac43a | 2530 | .name = "tmpfs", |
3c26ff6e | 2531 | .mount = ramfs_mount, |
853ac43a MM |
2532 | .kill_sb = kill_litter_super, |
2533 | }; | |
2534 | ||
41ffe5d5 | 2535 | int __init shmem_init(void) |
853ac43a | 2536 | { |
41ffe5d5 | 2537 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
853ac43a | 2538 | |
41ffe5d5 | 2539 | shm_mnt = kern_mount(&shmem_fs_type); |
853ac43a MM |
2540 | BUG_ON(IS_ERR(shm_mnt)); |
2541 | ||
2542 | return 0; | |
2543 | } | |
2544 | ||
41ffe5d5 | 2545 | int shmem_unuse(swp_entry_t swap, struct page *page) |
853ac43a MM |
2546 | { |
2547 | return 0; | |
2548 | } | |
2549 | ||
3f96b79a HD |
2550 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2551 | { | |
2552 | return 0; | |
2553 | } | |
2554 | ||
41ffe5d5 | 2555 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
94c1e62d | 2556 | { |
41ffe5d5 | 2557 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
94c1e62d HD |
2558 | } |
2559 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
2560 | ||
87946a72 DN |
2561 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2562 | /** | |
41ffe5d5 | 2563 | * mem_cgroup_get_shmem_target - find page or swap assigned to the shmem file |
87946a72 | 2564 | * @inode: the inode to be searched |
41ffe5d5 | 2565 | * @index: the page offset to be searched |
87946a72 | 2566 | * @pagep: the pointer for the found page to be stored |
41ffe5d5 | 2567 | * @swapp: the pointer for the found swap entry to be stored |
87946a72 DN |
2568 | * |
2569 | * If a page is found, refcount of it is incremented. Callers should handle | |
2570 | * these refcount. | |
2571 | */ | |
41ffe5d5 HD |
2572 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t index, |
2573 | struct page **pagep, swp_entry_t *swapp) | |
87946a72 DN |
2574 | { |
2575 | struct page *page = NULL; | |
2576 | ||
41ffe5d5 | 2577 | if ((index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
87946a72 | 2578 | goto out; |
41ffe5d5 | 2579 | page = find_get_page(inode->i_mapping, index); |
87946a72 DN |
2580 | out: |
2581 | *pagep = page; | |
41ffe5d5 | 2582 | *swapp = (swp_entry_t){0}; |
87946a72 DN |
2583 | } |
2584 | #endif | |
2585 | ||
0b0a0806 HD |
2586 | #define shmem_vm_ops generic_file_vm_ops |
2587 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2588 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2589 | #define shmem_acct_size(flags, size) 0 |
2590 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
2591 | |
2592 | #endif /* CONFIG_SHMEM */ | |
2593 | ||
2594 | /* common code */ | |
1da177e4 | 2595 | |
46711810 | 2596 | /** |
1da177e4 | 2597 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2598 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2599 | * @size: size to be set for the file | |
0b0a0806 | 2600 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2601 | */ |
168f5ac6 | 2602 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2603 | { |
2604 | int error; | |
2605 | struct file *file; | |
2606 | struct inode *inode; | |
2c48b9c4 AV |
2607 | struct path path; |
2608 | struct dentry *root; | |
1da177e4 LT |
2609 | struct qstr this; |
2610 | ||
2611 | if (IS_ERR(shm_mnt)) | |
2612 | return (void *)shm_mnt; | |
2613 | ||
285b2c4f | 2614 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
2615 | return ERR_PTR(-EINVAL); |
2616 | ||
2617 | if (shmem_acct_size(flags, size)) | |
2618 | return ERR_PTR(-ENOMEM); | |
2619 | ||
2620 | error = -ENOMEM; | |
2621 | this.name = name; | |
2622 | this.len = strlen(name); | |
2623 | this.hash = 0; /* will go */ | |
2624 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2625 | path.dentry = d_alloc(root, &this); |
2626 | if (!path.dentry) | |
1da177e4 | 2627 | goto put_memory; |
2c48b9c4 | 2628 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2629 | |
1da177e4 | 2630 | error = -ENOSPC; |
454abafe | 2631 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2632 | if (!inode) |
4b42af81 | 2633 | goto put_dentry; |
1da177e4 | 2634 | |
2c48b9c4 | 2635 | d_instantiate(path.dentry, inode); |
1da177e4 LT |
2636 | inode->i_size = size; |
2637 | inode->i_nlink = 0; /* It is unlinked */ | |
853ac43a MM |
2638 | #ifndef CONFIG_MMU |
2639 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2640 | if (error) | |
4b42af81 | 2641 | goto put_dentry; |
853ac43a | 2642 | #endif |
4b42af81 AV |
2643 | |
2644 | error = -ENFILE; | |
2c48b9c4 | 2645 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2646 | &shmem_file_operations); |
2647 | if (!file) | |
2648 | goto put_dentry; | |
2649 | ||
1da177e4 LT |
2650 | return file; |
2651 | ||
1da177e4 | 2652 | put_dentry: |
2c48b9c4 | 2653 | path_put(&path); |
1da177e4 LT |
2654 | put_memory: |
2655 | shmem_unacct_size(flags, size); | |
2656 | return ERR_PTR(error); | |
2657 | } | |
395e0ddc | 2658 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2659 | |
46711810 | 2660 | /** |
1da177e4 | 2661 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2662 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2663 | */ | |
2664 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2665 | { | |
2666 | struct file *file; | |
2667 | loff_t size = vma->vm_end - vma->vm_start; | |
2668 | ||
2669 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2670 | if (IS_ERR(file)) | |
2671 | return PTR_ERR(file); | |
2672 | ||
2673 | if (vma->vm_file) | |
2674 | fput(vma->vm_file); | |
2675 | vma->vm_file = file; | |
2676 | vma->vm_ops = &shmem_vm_ops; | |
bee4c36a | 2677 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
2678 | return 0; |
2679 | } | |
d9d90e5e HD |
2680 | |
2681 | /** | |
2682 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
2683 | * @mapping: the page's address_space | |
2684 | * @index: the page index | |
2685 | * @gfp: the page allocator flags to use if allocating | |
2686 | * | |
2687 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
2688 | * with any new page allocations done using the specified allocation flags. | |
2689 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
2690 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
2691 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
2692 | * | |
68da9f05 HD |
2693 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
2694 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
2695 | */ |
2696 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
2697 | pgoff_t index, gfp_t gfp) | |
2698 | { | |
68da9f05 HD |
2699 | #ifdef CONFIG_SHMEM |
2700 | struct inode *inode = mapping->host; | |
9276aad6 | 2701 | struct page *page; |
68da9f05 HD |
2702 | int error; |
2703 | ||
2704 | BUG_ON(mapping->a_ops != &shmem_aops); | |
2705 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); | |
2706 | if (error) | |
2707 | page = ERR_PTR(error); | |
2708 | else | |
2709 | unlock_page(page); | |
2710 | return page; | |
2711 | #else | |
2712 | /* | |
2713 | * The tiny !SHMEM case uses ramfs without swap | |
2714 | */ | |
d9d90e5e | 2715 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 2716 | #endif |
d9d90e5e HD |
2717 | } |
2718 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |